->follow_link() without dropping from RCU mode
Subsystems (39)
Al Viro
maintainerPATCH 1/1 ->follow_link() without dropping from RCU mode
Right now we stay in RCU mode for fast symlink traversal.
However, anything trickier drops out of RCU mode - back in 4.2 the symlink-related pile had grown too large to add this on top of everything else. Below is an attempt to do that now.
Those who prefer to use git for review can find that series in git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git work.symlinks The branch is 4.4-rc1-based, only lightly tested so far (ltp and xfstests pass without regressions, though).
What's in there:
1) switch befs long symlinks to page_symlink_operations
2) logfs: don't duplicate page_symlink_inode_operations
3) udf: don't duplicate page_symlink_inode_operations
4) ufs: get rid of ->setattr() for symlinks
Simplifying things a bit by switching them to page_symlink_operations
where possible.
5) namei: page_getlink() and page_follow_link_light() are the same thing Get rid of some code duplication
6) [vfs] don't put symlink bodies in pagecache into highmem Bugfix for a long-standing mess. For pagecache-based symlinks we end
up with kmap() of the body for the duration of traversal. Which could take a long time if we walk into e.g. slow automount along the way. It's DoSable, actually. Not hard to fix - there's no reason to use GFP_HIGHUSER_MOVABLE for those guys; GFP_USER serves just as well.
7) [vfs] replace ->follow_link() with new method that could stay in RCU mode
Meat of the series - we switch to a new method (->get_link()) that
differs from ->follow_link() in getting dentry and inode separately; it can be called in RCU mode (with NULL dentry) and it should bail out with ERR_PTR(-ECHILD) if it needs non-RCU. All instances converted, most of them by making them bail out immediately in RCU mode. Some are trivialy RCU-safe, though; those do not bail out at all.
8) teach page_get_link() to work in RCU mode
9) teach shmem_get_link() to work in RCU mode
10) teach proc_self_get_link()/proc_thread_self_get_link() to work in RCU mode Teaching more instances to stay in RCU mode if they can. (8) is
similar to what Neil had done back in March, except for the lack of kmap mess to deal with.
One thing I'd left out is NFS; something similar to Neil's patch from
the March patchset would probably do, though.
Al Viro
maintainerPATCH 1/10 switch befs long symlinks to page_symlink_operations
From: Al Viro <[email protected]>
just give them the right ->readpage()...
Signed-off-by Al Viro <[email protected]>
--- fs/befs/linuxvfs.c | 41 ++++++++++++++++++++++------------------- 1 file changed, 22 insertions(+), 19 deletions(-)
fs/befs/linuxvfs.c +22 -19
@@ -42,7 +42,7 @@ static struct inode *befs_iget(struct super_block *, unsigned long);static struct inode *befs_alloc_inode (struct super_block *sb);static void befs_destroy_inode (struct inode *inode);static void befs_destroy_inodecache (void ); -static const char *befs_follow_link (struct dentry *,void **); +static int befs_symlink_readpage (struct file *,struct page *);static int befs_utf2nls (struct super_block *sb,const char *in,int in_len,char **out,int *out_len); static int befs_nls2utf(struct super_block *sb, const char *in, int in_len,
@@ -79,10 +79,8 @@ static const struct address_space_operations befs_aops = { .bmap = befs_bmap, }; -static const struct inode_operations befs_symlink_inode_operations = { - .readlink = generic_readlink, - .follow_link = befs_follow_link, - .put_link = kfree_put_link, +static const struct address_space_operations befs_symlink_aops = { + .readpage = befs_symlink_readpage, };/*
@@ -398,7 +396,8 @@ static struct inode *befs_iget(struct super_block *sb, unsigned long ino) inode->i_fop = &befs_dir_operations; }else if (S_ISLNK (inode->i_mode)) {if (befs_ino->i_flags &BEFS_LONG_SYMLINK ) { - inode->i_op = &befs_symlink_inode_operations; + inode->i_op = &page_symlink_inode_operations; + inode->i_mapping->a_ops = &befs_symlink_aops; }else { inode->i_link = befs_ino->i_data.symlink; inode->i_op = &simple_symlink_inode_operations;
@@ -463,31 +462,35 @@ befs_destroy_inodecache(void)* The data stream become link name. Unless the LONG_SYMLINK * flag is set. */ -static const char * -befs_follow_link (struct dentry *dentry,void **cookie) +static int befs_symlink_readpage (struct file *unused,struct page *page) { -struct super_block *sb = dentry->d_sb; -struct befs_inode_info *befs_ino =BEFS_I (d_inode (dentry)); +struct inode *inode = page->mapping->host; +struct super_block *sb = inode->i_sb; +struct befs_inode_info *befs_ino =BEFS_I (inode);befs_data_stream *data = &befs_ino->i_data.ds;befs_off_t len = data->size; -char *link; +char *link =kmap (page); -if (len ==0 ) { +if (len ==0 || len >PAGE_SIZE ) {befs_error (sb,"Long symlink with illegal length" ); -return ERR_PTR (-EIO ); + goto fail; }befs_debug (sb,"Follow long symlink" ); - link =kmalloc (len,GFP_NOFS ); -if (!link) -return ERR_PTR (-ENOMEM );if (befs_read_lsymlink (sb, data, link, len) != len) { -kfree (link);befs_error (sb,"Failed to read entire long symlink" ); -return ERR_PTR (-EIO ); + goto fail; } link[len -1 ] ='\0' ; -return *cookie = link; +SetPageUptodate (page); +kunmap (page); +unlock_page (page); +return 0 ; +fail: +SetPageError (page); +kunmap (page); +unlock_page (page); +return -EIO ; }/*
Signature · 1 line
2.1.4
Al Viro
maintainerPATCH 2/10 logfs: don't duplicate page_symlink_inode_operations
In reply to Al ViroFrom: Al Viro <[email protected]>
Signed-off-by Al Viro <[email protected]>
--- fs/logfs/dir.c | 8 +------- fs/logfs/inode.c | 2 +- fs/logfs/logfs.h | 1 - 3 files changed, 2 insertions(+), 9 deletions(-)
fs/logfs/dir.c +1 -7
@@ -528,7 +528,7 @@ static int logfs_symlink(struct inode *dir, struct dentry *dentry,if (IS_ERR (inode))return PTR_ERR (inode); - inode->i_op = &logfs_symlink_iops; + inode->i_op = &page_symlink_inode_operations; inode->i_mapping->a_ops = &logfs_reg_aops;return __logfs_create (dir, dentry, inode, target, destlen);
@@ -776,12 +776,6 @@ fail:return -EIO ; } -const struct inode_operations logfs_symlink_iops = { - .readlink = generic_readlink, - .follow_link = page_follow_link_light, - .put_link = page_put_link, -}; -const struct inode_operations logfs_dir_iops = { .create = logfs_create, .link = logfs_link,
fs/logfs/inode.c +1 -1
@@ -64,7 +64,7 @@ static void logfs_inode_setops(struct inode *inode) inode->i_mapping->a_ops = &logfs_reg_aops;break ;case S_IFLNK : - inode->i_op = &logfs_symlink_iops; + inode->i_op = &page_symlink_inode_operations; inode->i_mapping->a_ops = &logfs_reg_aops;break ;case S_IFSOCK :/* fall through */
fs/logfs/logfs.h +0 -1
@@ -495,7 +495,6 @@ static inline int logfs_get_sb_mtd(struct logfs_super *s, int mtdnr)#endif /* dir.c */ -extern const struct inode_operations logfs_symlink_iops;extern const struct inode_operations logfs_dir_iops;extern const struct file_operations logfs_dir_fops;int logfs_replay_journal (struct super_block *sb);
Signature · 1 line
2.1.4
Al Viro
maintainerPATCH 3/10 udf: don't duplicate page_symlink_inode_operations
In reply to Al ViroFrom: Al Viro <[email protected]>
Signed-off-by Al Viro <[email protected]>
--- fs/udf/inode.c | 2 +- fs/udf/namei.c | 7 +------ fs/udf/udfdecl.h | 1 - 3 files changed, 2 insertions(+), 8 deletions(-)
fs/udf/inode.c +1 -1
@@ -1540,7 +1540,7 @@ reread:break ;case ICBTAG_FILE_TYPE_SYMLINK : inode->i_data.a_ops = &udf_symlink_aops; - inode->i_op = &udf_symlink_inode_operations; + inode->i_op = &page_symlink_inode_operations; inode->i_mode =S_IFLNK |S_IRWXUGO ;break ;case ICBTAG_FILE_TYPE_MAIN :
fs/udf/namei.c +1 -6
@@ -921,7 +921,7 @@ static int udf_symlink(struct inode *dir, struct dentry *dentry, } inode->i_data.a_ops = &udf_symlink_aops; - inode->i_op = &udf_symlink_inode_operations; + inode->i_op = &page_symlink_inode_operations;if (iinfo->i_alloc_type !=ICBTAG_FLAG_AD_IN_ICB ) {struct kernel_lb_addr eloc;
@@ -1344,8 +1344,3 @@ const struct inode_operations udf_dir_inode_operations = { .rename = udf_rename, .tmpfile = udf_tmpfile, }; -const struct inode_operations udf_symlink_inode_operations = { - .readlink = generic_readlink, - .follow_link = page_follow_link_light, - .put_link = page_put_link, -};
fs/udf/udfdecl.h +0 -1
@@ -85,7 +85,6 @@ extern const struct inode_operations udf_dir_inode_operations;extern const struct file_operations udf_dir_operations;extern const struct inode_operations udf_file_inode_operations;extern const struct file_operations udf_file_operations; -extern const struct inode_operations udf_symlink_inode_operations;extern const struct address_space_operations udf_aops;extern const struct address_space_operations udf_adinicb_aops;extern const struct address_space_operations udf_symlink_aops;
Signature · 1 line
2.1.4
Al Viro
maintainerPATCH 4/10 ufs: get rid of ->setattr() for symlinks
In reply to Al ViroFrom: Al Viro <[email protected]>
It was to needed for a couple of months in 2010, until UFS quota support got dropped. Since then it's equivalent to simple_setattr() (i.e. the default) for everything except the regular files. And dropping it there allows to convert all UFS symlinks to {page,simple}_symlink_inode_operations, getting rid of fs/ufs/symlink.c completely.
Signed-off-by Al Viro <[email protected]>
--- fs/ufs/Makefile | 2 +- fs/ufs/inode.c | 4 ++-- fs/ufs/namei.c | 4 ++-- fs/ufs/symlink.c | 42 ------------------------------------------ fs/ufs/ufs.h | 4 ---- 5 files changed, 5 insertions(+), 51 deletions(-) delete mode 100644 fs/ufs/symlink.c
fs/ufs/Makefile +1 -1
@@ -5,5 +5,5 @@ obj-$(CONFIG_UFS_FS) += ufs.o ufs-objs := balloc.o cylinder.o dir.o file.o ialloc.o inode.o \ - namei.o super.o symlink.o util.o + namei.o super.o util.o ccflags-$(CONFIG_UFS_DEBUG) += -DDEBUG
fs/ufs/inode.c +2 -2
@@ -528,11 +528,11 @@ static void ufs_set_inode_ops(struct inode *inode) inode->i_mapping->a_ops = &ufs_aops; }else if (S_ISLNK (inode->i_mode)) {if (!inode->i_blocks) { - inode->i_op = &ufs_fast_symlink_inode_operations; inode->i_link = (char *)UFS_I (inode)->i_u1.i_symlink; + inode->i_op = &simple_symlink_inode_operations; }else { - inode->i_op = &ufs_symlink_inode_operations; inode->i_mapping->a_ops = &ufs_aops; + inode->i_op = &page_symlink_inode_operations; } }else init_special_inode(inode, inode->i_mode,
fs/ufs/namei.c +2 -2
@@ -123,14 +123,14 @@ static int ufs_symlink (struct inode * dir, struct dentry * dentry,if (l >UFS_SB (sb)->s_uspi->s_maxsymlinklen) {/* slow symlink */ - inode->i_op = &ufs_symlink_inode_operations; + inode->i_op = &page_symlink_inode_operations; inode->i_mapping->a_ops = &ufs_aops; err =page_symlink (inode, symname, l);if (err) goto out_fail; }else {/* fast symlink */ - inode->i_op = &ufs_fast_symlink_inode_operations; + inode->i_op = &simple_symlink_inode_operations; inode->i_link = (char *)UFS_I (inode)->i_u1.i_symlink;memcpy (inode->i_link, symname, l); inode->i_size = l-1 ;
fs/ufs/symlink.c deleted +0 -42
42 lines not on this page · raw message
fs/ufs/ufs.h +0 -4
@@ -136,10 +136,6 @@ extern __printf(3, 4)void ufs_panic (struct super_block *,const char *,const char *, ...);void ufs_mark_sb_dirty (struct super_block *sb); -/* symlink.c */ -extern const struct inode_operations ufs_fast_symlink_inode_operations; -extern const struct inode_operations ufs_symlink_inode_operations; -static inline struct ufs_sb_info *UFS_SB (struct super_block *sb) {return sb->s_fs_info;
Signature · 1 line
2.1.4
Al Viro
maintainerPATCH 5/10 namei: page_getlink() and page_follow_link_light() are the same thing
In reply to Al ViroFrom: Al Viro <[email protected]>
Signed-off-by Al Viro <[email protected]>
--- fs/namei.c | 32 +++++++++++++------------------- 1 file changed, 13 insertions(+), 19 deletions(-)
fs/namei.c +13 -19
@@ -4519,7 +4519,7 @@ int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen)EXPORT_SYMBOL (generic_readlink);/* get the link contents into pagecache */ -static char *page_getlink (struct dentry * dentry,struct page **ppage) +static const char *page_getlink (struct dentry * dentry,void **cookie) {char *kaddr;struct page *page;
@@ -4527,31 +4527,15 @@ static char *page_getlink(struct dentry * dentry, struct page **ppage) page =read_mapping_page (mapping,0 ,NULL );if (IS_ERR (page))return (char *)page; - *ppage = page; + *cookie = page; kaddr =kmap (page);nd_terminate_link (kaddr, dentry->d_inode->i_size,PAGE_SIZE -1 );return kaddr; } -int page_readlink (struct dentry *dentry,char __user *buffer,int buflen) -{ -struct page *page =NULL ; -int res =readlink_copy (buffer, buflen,page_getlink (dentry, &page)); -if (page) { -kunmap (page); -page_cache_release (page); - } -return res; -} -EXPORT_SYMBOL (page_readlink); -const char *page_follow_link_light (struct dentry *dentry,void **cookie) { -struct page *page =NULL ; -char *res =page_getlink (dentry, &page); -if (!IS_ERR (res)) - *cookie = page; -return res; +return page_getlink (dentry, cookie); }EXPORT_SYMBOL (page_follow_link_light);
@@ -4563,6 +4547,16 @@ void page_put_link(struct inode *unused, void *cookie) }EXPORT_SYMBOL (page_put_link); +int page_readlink (struct dentry *dentry,char __user *buffer,int buflen) +{ +void *cookie =NULL ; +int res =readlink_copy (buffer, buflen,page_getlink (dentry, &cookie)); +if (cookie) +page_put_link (NULL , cookie); +return res; +} +EXPORT_SYMBOL (page_readlink); +/* * The nofs argument instructs pagecache_write_begin to pass AOP_FLAG_NOFS */
Signature · 1 line
2.1.4
Al Viro
maintainerPATCH 6/10 don't put symlink bodies in pagecache into highmem
In reply to Al ViroFrom: Al Viro <[email protected]>
kmap() in page_follow_link_light() needed to go - allowing to hold an arbitrary number of kmaps for long is a great way to deadlocking the system.
new helper (inode_nohigh(inode)) needs to be used for pagecache symlinks inodes; done for all in-tree cases. page_follow_link_light() instrumented to yell about anything missed.
Signed-off-by Al Viro <[email protected]>
--- Documentation/filesystems/porting | 5 +++++ fs/affs/inode.c | 1 + fs/affs/namei.c | 1 + fs/affs/symlink.c | 4 +--- fs/afs/inode.c | 1 + fs/befs/linuxvfs.c | 5 ++--- fs/btrfs/inode.c | 2 ++ fs/coda/cnode.c | 1 + fs/coda/symlink.c | 4 +--- fs/cramfs/inode.c | 1 + fs/efs/inode.c | 1 + fs/efs/symlink.c | 4 +--- fs/exofs/inode.c | 1 + fs/exofs/namei.c | 1 + fs/ext2/inode.c | 1 + fs/ext2/namei.c | 1 + fs/ext4/inode.c | 1 + fs/ext4/namei.c | 1 + fs/ext4/symlink.c | 10 +++------- fs/f2fs/inode.c | 1 + fs/f2fs/namei.c | 5 ++--- fs/freevxfs/vxfs_inode.c | 1 + fs/hfsplus/inode.c | 2 ++ fs/hpfs/inode.c | 1 + fs/hpfs/namei.c | 5 ++--- fs/hugetlbfs/inode.c | 1 + fs/isofs/inode.c | 1 + fs/isofs/rock.c | 4 +--- fs/jfs/inode.c | 1 + fs/jfs/namei.c | 1 + fs/logfs/dir.c | 1 + fs/logfs/inode.c | 1 + fs/minix/inode.c | 1 + fs/namei.c | 9 +++------ fs/ncpfs/inode.c | 1 + fs/nfs/inode.c | 5 +++-- fs/nfs/symlink.c | 2 +- fs/nilfs2/inode.c | 1 + fs/nilfs2/namei.c | 1 + fs/ocfs2/inode.c | 1 + fs/ocfs2/namei.c | 1 + fs/qnx4/inode.c | 1 + fs/qnx6/inode.c | 1 + fs/ramfs/inode.c | 1 + fs/reiserfs/inode.c | 1 + fs/reiserfs/namei.c | 1 + fs/romfs/super.c | 1 + fs/squashfs/inode.c | 2 ++ fs/sysv/inode.c | 1 + fs/udf/inode.c | 1 + fs/udf/namei.c | 1 + fs/udf/symlink.c | 4 +--- fs/ufs/inode.c | 1 + fs/ufs/namei.c | 1 + include/linux/fs.h | 4 ++++ mm/shmem.c | 9 +++------ 56 files changed, 77 insertions(+), 46 deletions(-)
Documentation/filesystems/porting +5 -0
@@ -504,3 +504,8 @@ in your dentry operations instead. [mandatory] __fd_install() & fd_install() can now sleep. Callers should not hold a spinlock or other resources that do not allow a schedule. +-- +[mandatory] + any symlink that might use page_follow_link_light/page_put_link() must + have inode_nohigh(inode) called before anything might start playing with + its pagecache.
fs/affs/inode.c +1 -0
@@ -140,6 +140,7 @@ struct inode *affs_iget(struct super_block *sb, unsigned long ino)break ;case ST_SOFTLINK : inode->i_mode |=S_IFLNK ; +inode_nohigh (inode); inode->i_op = &affs_symlink_inode_operations; inode->i_data.a_ops = &affs_symlink_aops;break ;
fs/affs/namei.c +1 -0
@@ -344,6 +344,7 @@ affs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)return -ENOSPC ; inode->i_op = &affs_symlink_inode_operations; +inode_nohigh (inode); inode->i_data.a_ops = &affs_symlink_aops; inode->i_mode =S_IFLNK |0777 ;mode_to_prot (inode);
fs/affs/symlink.c +1 -3
@@ -14,7 +14,7 @@ static int affs_symlink_readpage(struct file *file, struct page *page) {struct buffer_head *bh;struct inode *inode = page->mapping->host; -char *link =kmap (page); +char *link =page_address (page);struct slink_front *lf;int i, j;char c;
@@ -57,12 +57,10 @@ static int affs_symlink_readpage(struct file *file, struct page *page) link[i] ='\0' ;affs_brelse (bh);SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ; fail:SetPageError (page); -kunmap (page);unlock_page (page);return -EIO ; }
fs/afs/inode.c +1 -0
@@ -56,6 +56,7 @@ static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)case AFS_FTYPE_SYMLINK : inode->i_mode =S_IFLNK | vnode->status.mode; inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode);break ;default :printk ("kAFS: AFS vnode with undefined type\n" );
fs/befs/linuxvfs.c +2 -3
@@ -397,6 +397,7 @@ static struct inode *befs_iget(struct super_block *sb, unsigned long ino) }else if (S_ISLNK (inode->i_mode)) {if (befs_ino->i_flags &BEFS_LONG_SYMLINK ) { inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &befs_symlink_aops; }else { inode->i_link = befs_ino->i_data.symlink;
@@ -469,7 +470,7 @@ static int befs_symlink_readpage(struct file *unused, struct page *page)struct befs_inode_info *befs_ino =BEFS_I (inode);befs_data_stream *data = &befs_ino->i_data.ds;befs_off_t len = data->size; -char *link =kmap (page); +char *link =page_address (page);if (len ==0 || len >PAGE_SIZE ) {befs_error (sb,"Long symlink with illegal length" );
@@ -483,12 +484,10 @@ static int befs_symlink_readpage(struct file *unused, struct page *page) } link[len -1 ] ='\0' ;SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ; fail:SetPageError (page); -kunmap (page);unlock_page (page);return -EIO ; }
fs/btrfs/inode.c +2 -0
@@ -3774,6 +3774,7 @@ cache_acl:break ;case S_IFLNK : inode->i_op = &btrfs_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &btrfs_symlink_aops;break ;default :
@@ -9727,6 +9728,7 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,btrfs_free_path (path); inode->i_op = &btrfs_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &btrfs_symlink_aops;inode_set_bytes (inode, name_len);btrfs_i_size_write (inode, name_len);
fs/coda/cnode.c +1 -0
@@ -35,6 +35,7 @@ static void coda_fill_inode(struct inode *inode, struct coda_vattr *attr) inode->i_fop = &coda_dir_operations; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &coda_symlink_inode_operations; +inode_nohigh (inode); inode->i_data.a_ops = &coda_symlink_aops; inode->i_mapping = &inode->i_data; }else
fs/coda/symlink.c +1 -3
@@ -26,7 +26,7 @@ static int coda_symlink_filler(struct file *file, struct page *page)int error;struct coda_inode_info *cii;unsigned int len =PAGE_SIZE ; -char *p =kmap (page); +char *p =page_address (page); cii =ITOC (inode);
@@ -34,13 +34,11 @@ static int coda_symlink_filler(struct file *file, struct page *page)if (error) goto fail;SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ; fail:SetPageError (page); -kunmap (page);unlock_page (page);return error; }
fs/cramfs/inode.c +1 -0
@@ -100,6 +100,7 @@ static struct inode *get_cramfs_inode(struct super_block *sb,break ;case S_IFLNK : inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode); inode->i_data.a_ops = &cramfs_aops;break ;default :
fs/efs/inode.c +1 -0
@@ -151,6 +151,7 @@ struct inode *efs_iget(struct super_block *super, unsigned long ino)break ;case S_IFLNK : inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode); inode->i_data.a_ops = &efs_symlink_aops;break ;case S_IFCHR :
fs/efs/symlink.c +1 -3
@@ -13,7 +13,7 @@static int efs_symlink_readpage (struct file *file,struct page *page) { -char *link =kmap (page); +char *link =page_address (page);struct buffer_head * bh;struct inode * inode = page->mapping->host;efs_block_t size = inode->i_size;
@@ -39,12 +39,10 @@ static int efs_symlink_readpage(struct file *file, struct page *page) } link[size] ='\0' ;SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ; fail:SetPageError (page); -kunmap (page);unlock_page (page);return err; }
fs/exofs/inode.c +1 -0
@@ -1227,6 +1227,7 @@ struct inode *exofs_iget(struct super_block *sb, unsigned long ino) inode->i_link = (char *)oi->i_data; }else { inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &exofs_aops; } }else {
fs/exofs/namei.c +1 -0
@@ -111,6 +111,7 @@ static int exofs_symlink(struct inode *dir, struct dentry *dentry,if (l >sizeof (oi->i_data)) {/* slow symlink */ inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &exofs_aops;memset (oi->i_data,0 ,sizeof (oi->i_data));
fs/ext2/inode.c +1 -0
@@ -1420,6 +1420,7 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino) sizeof(ei->i_data) - 1); }else { inode->i_op = &ext2_symlink_inode_operations; +inode_nohigh (inode);if (test_opt (inode->i_sb,NOBH )) inode->i_mapping->a_ops = &ext2_nobh_aops;else
fs/ext2/namei.c +1 -0
@@ -183,6 +183,7 @@ static int ext2_symlink (struct inode * dir, struct dentry * dentry,if (l >sizeof (EXT2_I (inode)->i_data)) {/* slow symlink */ inode->i_op = &ext2_symlink_inode_operations; +inode_nohigh (inode);if (test_opt (inode->i_sb,NOBH )) inode->i_mapping->a_ops = &ext2_nobh_aops;else
fs/ext4/inode.c +1 -0
@@ -4283,6 +4283,7 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino) inode->i_op = &ext4_symlink_inode_operations;ext4_set_aops (inode); } +inode_nohigh (inode); }else if (S_ISCHR (inode->i_mode) ||S_ISBLK (inode->i_mode) ||S_ISFIFO (inode->i_mode) ||S_ISSOCK (inode->i_mode)) { inode->i_op = &ext4_special_inode_operations;
fs/ext4/namei.c +1 -0
@@ -3132,6 +3132,7 @@ static int ext4_symlink(struct inode *dir,if ((disk_link.len >EXT4_N_BLOCKS *4 )) {if (!encryption_required) inode->i_op = &ext4_symlink_inode_operations; +inode_nohigh (inode);ext4_set_aops (inode);/* * We cannot call page_symlink() with transaction started
fs/ext4/symlink.c +3 -7
@@ -45,7 +45,7 @@ static const char *ext4_encrypted_follow_link(struct dentry *dentry, void **cook cpage =read_mapping_page (inode->i_mapping,0 ,NULL );if (IS_ERR (cpage))return ERR_CAST (cpage); - caddr =kmap (cpage); + caddr =page_address (cpage); caddr[size] =0 ; }
@@ -75,16 +75,12 @@ static const char *ext4_encrypted_follow_link(struct dentry *dentry, void **cook/* Null-terminate the name */ if (res <= plen) paddr[res] ='\0' ; -if (cpage) { -kunmap (cpage); +if (cpage)page_cache_release (cpage); - }return *cookie = paddr; errout: -if (cpage) { -kunmap (cpage); +if (cpage)page_cache_release (cpage); - }kfree (paddr);return ERR_PTR (res); }
fs/f2fs/inode.c +1 -0
@@ -202,6 +202,7 @@ make_now: inode->i_op = &f2fs_encrypted_symlink_inode_operations; else inode->i_op = &f2fs_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &f2fs_dblock_aops; }else if (S_ISCHR (inode->i_mode) ||S_ISBLK (inode->i_mode) ||S_ISFIFO (inode->i_mode) ||S_ISSOCK (inode->i_mode)) {
fs/f2fs/namei.c +2 -3
@@ -351,6 +351,7 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry, inode->i_op = &f2fs_encrypted_symlink_inode_operations; else inode->i_op = &f2fs_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &f2fs_dblock_aops;f2fs_lock_op (sbi);
@@ -942,7 +943,7 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook cpage =read_mapping_page (inode->i_mapping,0 ,NULL );if (IS_ERR (cpage))return ERR_CAST (cpage); - caddr =kmap (cpage); + caddr =page_address (cpage); caddr[size] =0 ;/* Symlink is encrypted */
@@ -982,13 +983,11 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook/* Null-terminate the name */ paddr[res] ='\0' ; -kunmap (cpage);page_cache_release (cpage);return *cookie = paddr; errout:kfree (cstr.name);f2fs_fname_crypto_free_buffer (&pstr); -kunmap (cpage);page_cache_release (cpage);return ERR_PTR (res); }
fs/freevxfs/vxfs_inode.c +1 -0
@@ -326,6 +326,7 @@ vxfs_iget(struct super_block *sbp, ino_t ino) }else if (S_ISLNK (ip->i_mode)) {if (!VXFS_ISIMMED (vip)) { ip->i_op = &page_symlink_inode_operations; +inode_nohigh (ip); ip->i_mapping->a_ops = &vxfs_aops; }else { ip->i_op = &simple_symlink_inode_operations;
fs/hfsplus/inode.c +2 -0
@@ -403,6 +403,7 @@ struct inode *hfsplus_new_inode(struct super_block *sb, umode_t mode) }else if (S_ISLNK (inode->i_mode)) { sbi->file_count++; inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &hfsplus_aops; hip->clump_blocks =1 ; }else
@@ -526,6 +527,7 @@ int hfsplus_cat_read_inode(struct inode *inode, struct hfs_find_data *fd) inode->i_mapping->a_ops = &hfsplus_aops; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &hfsplus_aops; }else { init_special_inode(inode, inode->i_mode,
fs/hpfs/inode.c +1 -0
@@ -77,6 +77,7 @@ void hpfs_read_inode(struct inode *i)kfree (ea); i->i_mode =S_IFLNK |0777 ; i->i_op = &page_symlink_inode_operations; +inode_nohigh (i); i->i_data.a_ops = &hpfs_symlink_aops;set_nlink (i,1 ); i->i_size = ea_size;
fs/hpfs/namei.c +2 -3
@@ -332,6 +332,7 @@ static int hpfs_symlink(struct inode *dir, struct dentry *dentry, const char *sy result->i_blocks =1 ;set_nlink (result,1 ); result->i_size =strlen (symlink); +inode_nohigh (result); result->i_op = &page_symlink_inode_operations; result->i_data.a_ops = &hpfs_symlink_aops;
@@ -500,7 +501,7 @@ out:static int hpfs_symlink_readpage (struct file *file,struct page *page) { -char *link =kmap (page); +char *link =page_address (page);struct inode *i = page->mapping->host;struct fnode *fnode;struct buffer_head *bh;
@@ -516,14 +517,12 @@ static int hpfs_symlink_readpage(struct file *file, struct page *page) goto fail;hpfs_unlock (i->i_sb);SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ; fail:hpfs_unlock (i->i_sb);SetPageError (page); -kunmap (page);unlock_page (page);return err; }
fs/hugetlbfs/inode.c +1 -0
@@ -761,6 +761,7 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb,break ;case S_IFLNK : inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode);break ; }lockdep_annotate_inode_mutex_key (inode);
fs/isofs/inode.c +1 -0
@@ -1417,6 +1417,7 @@ static int isofs_read_inode(struct inode *inode, int relocated) inode->i_fop = &isofs_dir_operations; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode); inode->i_data.a_ops = &isofs_symlink_aops; }else /* XXX - parse_rock_ridge_inode() had already set i_rdev. */
fs/isofs/rock.c +1 -3
@@ -687,7 +687,7 @@ static int rock_ridge_symlink_readpage(struct file *file, struct page *page)struct inode *inode = page->mapping->host;struct iso_inode_info *ei =ISOFS_I (inode);struct isofs_sb_info *sbi =ISOFS_SB (inode->i_sb); -char *link =kmap (page); +char *link =page_address (page);unsigned long bufsize =ISOFS_BUFFER_SIZE (inode);struct buffer_head *bh;char *rpnt = link;
@@ -774,7 +774,6 @@ repeat:brelse (bh); *rpnt ='\0' ;SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ;
@@ -791,7 +790,6 @@ fail:brelse (bh); error:SetPageError (page); -kunmap (page);unlock_page (page);return -EIO ; }
fs/jfs/inode.c +1 -0
@@ -60,6 +60,7 @@ struct inode *jfs_iget(struct super_block *sb, unsigned long ino) }else if (S_ISLNK (inode->i_mode)) {if (inode->i_size >=IDATASIZE ) { inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &jfs_aops; }else { inode->i_op = &jfs_fast_symlink_inode_operations;
fs/jfs/namei.c +1 -0
@@ -983,6 +983,7 @@ static int jfs_symlink(struct inode *dip, struct dentry *dentry,jfs_info ("jfs_symlink: allocate extent ip:0x%p" , ip); ip->i_op = &jfs_symlink_inode_operations; +inode_nohigh (ip); ip->i_mapping->a_ops = &jfs_aops;/*
fs/logfs/dir.c +1 -0
@@ -529,6 +529,7 @@ static int logfs_symlink(struct inode *dir, struct dentry *dentry,return PTR_ERR (inode); inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &logfs_reg_aops;return __logfs_create (dir, dentry, inode, target, destlen);
fs/logfs/inode.c +1 -0
@@ -65,6 +65,7 @@ static void logfs_inode_setops(struct inode *inode)break ;case S_IFLNK : inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &logfs_reg_aops;break ;case S_IFSOCK :/* fall through */
fs/minix/inode.c +1 -0
@@ -452,6 +452,7 @@ void minix_set_inode(struct inode *inode, dev_t rdev) inode->i_mapping->a_ops = &minix_aops; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &minix_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &minix_aops; }else init_special_inode (inode, inode->i_mode, rdev);
fs/namei.c +3 -6
@@ -4528,7 +4528,8 @@ static const char *page_getlink(struct dentry * dentry, void **cookie)if (IS_ERR (page))return (char *)page; *cookie = page; - kaddr =kmap (page); +BUG_ON (mapping_gfp_mask (mapping) & __GFP_HIGHMEM); + kaddr =page_address (page);nd_terminate_link (kaddr, dentry->d_inode->i_size,PAGE_SIZE -1 );return kaddr; }
@@ -4542,7 +4543,6 @@ EXPORT_SYMBOL(page_follow_link_light);void page_put_link (struct inode *unused,void *cookie) {struct page *page = cookie; -kunmap (page);page_cache_release (page); }EXPORT_SYMBOL (page_put_link);
@@ -4566,7 +4566,6 @@ int __page_symlink(struct inode *inode, const char *symname, int len, int nofs)struct page *page;void *fsdata;int err; -char *kaddr;unsigned int flags =AOP_FLAG_UNINTERRUPTIBLE ;if (nofs) flags |=AOP_FLAG_NOFS ;
@@ -4577,9 +4576,7 @@ retry:if (err) goto fail; - kaddr =kmap_atomic (page); -memcpy (kaddr, symname, len-1 ); -kunmap_atomic (kaddr); +memcpy (page_address (page), symname, len-1 ); err =pagecache_write_end (NULL , mapping,0 , len-1 , len-1 , page, fsdata);
fs/ncpfs/inode.c +1 -0
@@ -283,6 +283,7 @@ ncp_iget(struct super_block *sb, struct ncp_entry_info *info)#if defined(CONFIG_NCPFS_EXTRAS ) || defined(CONFIG_NCPFS_NFS_NS ) } else if (S_ISLNK(inode->i_mode)) { inode->i_op = &ncp_symlink_inode_operations; +inode_nohigh (inode); inode->i_data.a_ops = &ncp_symlink_aops;#endif }else {
fs/nfs/inode.c +3 -2
@@ -408,9 +408,10 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr, st inode->i_fop =NULL ; inode->i_flags |=S_AUTOMOUNT ; } - }else if (S_ISLNK (inode->i_mode)) + }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &nfs_symlink_inode_operations; -else +inode_nohigh (inode); + }else init_special_inode (inode, inode->i_mode, fattr->rdev);memset (&inode->i_atime,0 ,sizeof (inode->i_atime));
fs/nfs/symlink.c +1 -1
@@ -56,7 +56,7 @@ static const char *nfs_follow_link(struct dentry *dentry, void **cookie)if (IS_ERR (page))return ERR_CAST (page); *cookie = page; -return kmap (page); +return page_address (page); }/*
fs/nilfs2/inode.c +1 -0
@@ -510,6 +510,7 @@ static int __nilfs_read_inode(struct super_block *sb, inode->i_mapping->a_ops = &nilfs_aops; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &nilfs_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &nilfs_aops; }else { inode->i_op = &nilfs_special_inode_operations;
fs/nilfs2/namei.c +1 -0
@@ -161,6 +161,7 @@ static int nilfs_symlink(struct inode *dir, struct dentry *dentry,/* slow symlink */ inode->i_op = &nilfs_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &nilfs_aops; err =page_symlink (inode, symname, l);if (err)
fs/ocfs2/inode.c +1 -0
@@ -361,6 +361,7 @@ void ocfs2_populate_inode(struct inode *inode, struct ocfs2_dinode *fe,break ;case S_IFLNK : inode->i_op = &ocfs2_symlink_inode_operations; +inode_nohigh (inode);i_size_write (inode,le64_to_cpu (fe->i_size));break ;default :
fs/ocfs2/namei.c +1 -0
@@ -1958,6 +1958,7 @@ static int ocfs2_symlink(struct inode *dir, inode->i_rdev =0 ; newsize = l -1 ; inode->i_op = &ocfs2_symlink_inode_operations; +inode_nohigh (inode);if (l >ocfs2_fast_symlink_chars (sb)) {u32 offset =0 ;
fs/qnx4/inode.c +1 -0
@@ -316,6 +316,7 @@ struct inode *qnx4_iget(struct super_block *sb, unsigned long ino) inode->i_fop = &qnx4_dir_operations; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &qnx4_aops;qnx4_i (inode)->mmu_private = inode->i_size; }else {
fs/qnx6/inode.c +1 -0
@@ -582,6 +582,7 @@ struct inode *qnx6_iget(struct super_block *sb, unsigned ino) inode->i_mapping->a_ops = &qnx6_aops; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &qnx6_aops; }else init_special_inode (inode, inode->i_mode,0 );
fs/ramfs/inode.c +1 -0
@@ -79,6 +79,7 @@ struct inode *ramfs_get_inode(struct super_block *sb,break ;case S_IFLNK : inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode);break ; } }
fs/reiserfs/inode.c +1 -0
@@ -1361,6 +1361,7 @@ static void init_inode(struct inode *inode, struct treepath *path) inode->i_fop = &reiserfs_dir_operations; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &reiserfs_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &reiserfs_address_space_operations; }else { inode->i_blocks =0 ;
fs/reiserfs/namei.c +1 -0
@@ -1170,6 +1170,7 @@ static int reiserfs_symlink(struct inode *parent_dir,reiserfs_update_inode_transaction (parent_dir); inode->i_op = &reiserfs_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &reiserfs_address_space_operations; retval = reiserfs_add_entry(&th, parent_dir, dentry->d_name.name,
fs/romfs/super.c +1 -0
@@ -360,6 +360,7 @@ static struct inode *romfs_iget(struct super_block *sb, unsigned long pos)break ;case ROMFH_SYM : i->i_op = &page_symlink_inode_operations; +inode_nohigh (i); i->i_data.a_ops = &romfs_aops; mode |=S_IRWXUGO ;break ;
fs/squashfs/inode.c +2 -0
@@ -41,6 +41,7 @@#include <linux/fs.h> #include <linux/vfs.h> #include <linux/xattr.h> +#include <linux/pagemap.h> #include "squashfs_fs.h" #include "squashfs_fs_sb.h"
@@ -291,6 +292,7 @@ int squashfs_read_inode(struct inode *inode, long long ino)set_nlink (inode,le32_to_cpu (sqsh_ino->nlink)); inode->i_size =le32_to_cpu (sqsh_ino->symlink_size); inode->i_op = &squashfs_symlink_inode_ops; +inode_nohigh (inode); inode->i_data.a_ops = &squashfs_symlink_aops; inode->i_mode |=S_IFLNK ;squashfs_i (inode)->start = block;
fs/sysv/inode.c +1 -0
@@ -164,6 +164,7 @@ void sysv_set_inode(struct inode *inode, dev_t rdev) }else if (S_ISLNK (inode->i_mode)) {if (inode->i_blocks) { inode->i_op = &sysv_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &sysv_aops; }else { inode->i_op = &simple_symlink_inode_operations;
fs/udf/inode.c +1 -0
@@ -1541,6 +1541,7 @@ reread:case ICBTAG_FILE_TYPE_SYMLINK : inode->i_data.a_ops = &udf_symlink_aops; inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode); inode->i_mode =S_IFLNK |S_IRWXUGO ;break ;case ICBTAG_FILE_TYPE_MAIN :
fs/udf/namei.c +1 -0
@@ -922,6 +922,7 @@ static int udf_symlink(struct inode *dir, struct dentry *dentry, inode->i_data.a_ops = &udf_symlink_aops; inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode);if (iinfo->i_alloc_type !=ICBTAG_FLAG_AD_IN_ICB ) {struct kernel_lb_addr eloc;
fs/udf/symlink.c +1 -3
@@ -107,7 +107,7 @@ static int udf_symlink_filler(struct file *file, struct page *page)struct buffer_head *bh =NULL ;unsigned char *symlink;int err; -unsigned char *p =kmap (page); +unsigned char *p =page_address (page);struct udf_inode_info *iinfo;uint32_t pos;
@@ -141,7 +141,6 @@ static int udf_symlink_filler(struct file *file, struct page *page)up_read (&iinfo->i_data_sem);SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ;
@@ -149,7 +148,6 @@ out_unlock_inode:up_read (&iinfo->i_data_sem);SetPageError (page); out_unmap: -kunmap (page);unlock_page (page);return err; }
fs/ufs/inode.c +1 -0
@@ -533,6 +533,7 @@ static void ufs_set_inode_ops(struct inode *inode) }else { inode->i_mapping->a_ops = &ufs_aops; inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode); } }else init_special_inode(inode, inode->i_mode,
fs/ufs/namei.c +1 -0
@@ -124,6 +124,7 @@ static int ufs_symlink (struct inode * dir, struct dentry * dentry,if (l >UFS_SB (sb)->s_uspi->s_maxsymlinklen) {/* slow symlink */ inode->i_op = &page_symlink_inode_operations; +inode_nohigh (inode); inode->i_mapping->a_ops = &ufs_aops; err =page_symlink (inode, symname, l);if (err)
include/linux/fs.h +4 -0
@@ -3026,4 +3026,8 @@ static inline bool dir_relax(struct inode *inode)extern bool path_noexec (const struct path *path); +/* macro to avoid the mess with include dependencies */ +#define inode_nohigh (inode) \ + mapping_set_gfp_mask((inode)->i_mapping, GFP_USER) +#endif /* _LINUX_FS_H */
mm/shmem.c +3 -6
@@ -2444,7 +2444,6 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *sint len;struct inode *inode;struct page *page; -char *kaddr;struct shmem_inode_info *info; len =strlen (symname) +1 ;
@@ -2483,9 +2482,8 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s } inode->i_mapping->a_ops = &shmem_aops; inode->i_op = &shmem_symlink_inode_operations; - kaddr =kmap_atomic (page); -memcpy (kaddr, symname, len); -kunmap_atomic (kaddr); +inode_nohigh (inode); +memcpy (page_address (page), symname, len);SetPageUptodate (page);set_page_dirty (page);unlock_page (page);
@@ -2506,13 +2504,12 @@ static const char *shmem_follow_link(struct dentry *dentry, void **cookie)return ERR_PTR (error);unlock_page (page); *cookie = page; -return kmap (page); +return page_address (page); }static void shmem_put_link (struct inode *unused,void *cookie) {struct page *page = cookie; -kunmap (page);mark_page_accessed (page);page_cache_release (page); }
Signature · 1 line
2.1.4
Re: [PATCH 06/10] [vfs] don't put symlink bodies in pagecache into highmem
Quoted 7 lines · Al Viro
From: Al Viro <[email protected]>
kmap()inpage_follow_link_light()needed to go - allowing to hold an arbitrary number of kmaps for long is a great way to deadlocking the system.new helper (
inode_nohigh(inode)) needs to be used for pagecache
inode_nohighmem() seems like a better name as it's self-documenting at the call site.
Cheers,
Dave.
Signature · 2 lines
Dave Chinner [email protected]
Al Viro
maintainerPATCH 7/10 replace ->follow_link() with new method that could stay in RCU mode
In reply to Al ViroFrom: Al Viro <[email protected]>
new method: ->get_link(); replacement of ->follow_link(). The differences are:
* inode and dentry are passed separately
* might be called both in RCU and non-RCU mode;
the former is indicated by passing it a NULL dentry.
* when called that way it isn't allowed to block
and should return ERR_PTR(-ECHILD) if it needs to be called
in non-RCU mode.
It's a flagday change - the old method is gone, all in-tree instances converted. Conversion isn't hard; said that, so far very few instances do not immediately bail out when called in RCU mode. That'll change in the next commits.
Signed-off-by Al Viro <[email protected]>
--- Documentation/filesystems/Locking | 4 +-- Documentation/filesystems/porting | 6 ++++ drivers/staging/lustre/lustre/llite/symlink.c | 8 +++-- fs/9p/vfs_inode.c | 17 +++++++--- fs/9p/vfs_inode_dotl.c | 14 ++++++--- fs/affs/symlink.c | 4 +-- fs/autofs4/symlink.c | 13 +++++--- fs/btrfs/inode.c | 2 +- fs/ceph/inode.c | 2 +- fs/cifs/cifsfs.c | 2 +- fs/cifs/cifsfs.h | 4 +-- fs/cifs/link.c | 6 ++-- fs/coda/cnode.c | 2 +- fs/configfs/symlink.c | 11 +++++-- fs/dcache.c | 2 +- fs/ecryptfs/inode.c | 12 +++++-- fs/ext2/symlink.c | 4 +-- fs/ext4/symlink.c | 13 +++++--- fs/f2fs/namei.c | 16 ++++++---- fs/fuse/dir.c | 9 ++++-- fs/gfs2/inode.c | 15 ++++++--- fs/hostfs/hostfs_kern.c | 10 ++++-- fs/jffs2/symlink.c | 2 +- fs/jfs/symlink.c | 4 +-- fs/kernfs/symlink.c | 11 +++++-- fs/libfs.c | 9 +++--- fs/minix/inode.c | 2 +- fs/namei.c | 45 +++++++++++++++++---------- fs/ncpfs/inode.c | 2 +- fs/nfs/symlink.c | 9 ++++-- fs/nilfs2/namei.c | 2 +- fs/ocfs2/symlink.c | 2 +- fs/overlayfs/inode.c | 12 ++++--- fs/proc/base.c | 22 +++++++------ fs/proc/inode.c | 7 +++-- fs/proc/namespaces.c | 9 ++++-- fs/proc/self.c | 7 +++-- fs/proc/thread_self.c | 7 +++-- fs/reiserfs/namei.c | 2 +- fs/squashfs/symlink.c | 2 +- fs/sysv/inode.c | 2 +- fs/ubifs/file.c | 2 +- fs/xfs/xfs_iops.c | 8 +++-- include/linux/fs.h | 6 ++-- mm/shmem.c | 12 ++++--- 45 files changed, 232 insertions(+), 130 deletions(-)
Documentation/filesystems/Locking +2 -2
@@ -50,7 +50,7 @@ prototypes: int (*rename2) (struct inode *, struct dentry *, struct inode *, struct dentry *, unsigned int); int (*readlink) (struct dentry *, char __user *,int); - const char *(*follow_link) (struct dentry *, void **); + const char *(*get_link) (struct dentry *, struct inode *, void **); void (*put_link) (struct inode *, void *); void (*truncate) (struct inode *); int (*permission) (struct inode *, int, unsigned int);
@@ -83,7 +83,7 @@ rmdir: yes (both) (see below) rename: yes (all) (see below) rename2: yes (all) (see below) readlink: no -follow_link: no +get_link: no put_link: no setattr: yes permission: no (may not block if called in rcu-walk mode)
Documentation/filesystems/porting +6 -0
@@ -509,3 +509,9 @@ in your dentry operations instead. any symlink that might use page_follow_link_light/page_put_link() must have inode_nohigh(inode) called before anything might start playing with its pagecache. +-- +[mandatory] + ->follow_link() is replaced with ->get_link(); same API, except that + * ->get_link() gets inode as a separate argument + * ->get_link() may be called in RCU mode - in that case NULL + dentry is passed
drivers/staging/lustre/lustre/llite/symlink.c +5 -3
@@ -118,12 +118,14 @@ failed:return rc; } -static const char *ll_follow_link (struct dentry *dentry,void **cookie) +static const char *ll_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct inode *inode =d_inode (dentry);struct ptlrpc_request *request =NULL ;int rc;char *symname =NULL ; +if (!dentry) +return ERR_PTR (-ECHILD );CDEBUG (D_VFSTRACE ,"VFS Op\n" );ll_inode_size_lock (inode);
@@ -149,7 +151,7 @@ static void ll_put_link(struct inode *unused, void *cookie)struct inode_operations ll_fast_symlink_inode_operations = { .readlink = generic_readlink, .setattr = ll_setattr, - .follow_link = ll_follow_link, + .get_link = ll_get_link, .put_link = ll_put_link, .getattr = ll_getattr, .permission = ll_inode_permission,
fs/9p/vfs_inode.c +12 -5
@@ -1223,18 +1223,25 @@ ino_t v9fs_qid2ino(struct p9_qid *qid) }/** -* v9fs_vfs_follow_link - follow a symlink path +* v9fs_vfs_get_link - follow a symlink path * @dentry: dentry for symlink +* @inode: inode for symlink * @cookie: place to pass the data to put_link() */ -static const char *v9fs_vfs_follow_link (struct dentry *dentry,void **cookie) +static const char *v9fs_vfs_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct v9fs_session_info *v9ses =v9fs_dentry2v9ses (dentry); -struct p9_fid *fid =v9fs_fid_lookup (dentry); +struct v9fs_session_info *v9ses; +struct p9_fid *fid;struct p9_wstat *st;char *res; +if (!dentry) +return ERR_PTR (-ECHILD ); + + v9ses =v9fs_dentry2v9ses (dentry); + fid =v9fs_fid_lookup (dentry);p9_debug (P9_DEBUG_VFS ,"%pd\n" , dentry);if (IS_ERR (fid))
@@ -1452,7 +1459,7 @@ static const struct inode_operations v9fs_file_inode_operations = {static const struct inode_operations v9fs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = v9fs_vfs_follow_link, + .get_link = v9fs_vfs_get_link, .put_link = kfree_put_link, .getattr = v9fs_vfs_getattr, .setattr = v9fs_vfs_setattr,
fs/9p/vfs_inode_dotl.c +10 -4
@@ -899,20 +899,26 @@ error: }/** -* v9fs_vfs_follow_link_dotl - follow a symlink path +* v9fs_vfs_get_link_dotl - follow a symlink path * @dentry: dentry for symlink +* @inode: inode for symlink * @cookie: place to pass the data to put_link() */ static const char * -v9fs_vfs_follow_link_dotl (struct dentry *dentry,void **cookie) +v9fs_vfs_get_link_dotl (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct p9_fid *fid =v9fs_fid_lookup (dentry); +struct p9_fid *fid;char *target;int retval; +if (!dentry) +return ERR_PTR (-ECHILD ); +p9_debug (P9_DEBUG_VFS ,"%pd\n" , dentry); + fid =v9fs_fid_lookup (dentry);if (IS_ERR (fid))return ERR_CAST (fid); retval =p9_client_readlink (fid, &target);
@@ -984,7 +990,7 @@ const struct inode_operations v9fs_file_inode_operations_dotl = {const struct inode_operations v9fs_symlink_inode_operations_dotl = { .readlink = generic_readlink, - .follow_link = v9fs_vfs_follow_link_dotl, + .get_link = v9fs_vfs_get_link_dotl, .put_link = kfree_put_link, .getattr = v9fs_vfs_getattr_dotl, .setattr = v9fs_vfs_setattr_dotl,
fs/affs/symlink.c +2 -2
@@ -20,7 +20,7 @@ static int affs_symlink_readpage(struct file *file, struct page *page)char c;char lc; -pr_debug ("follow_link(ino=%lu)\n" , inode->i_ino); +pr_debug ("get_link(ino=%lu)\n" , inode->i_ino); bh =affs_bread (inode->i_sb, inode->i_ino);if (!bh)
@@ -71,7 +71,7 @@ const struct address_space_operations affs_symlink_aops = {const struct inode_operations affs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .setattr = affs_notify_change, };
fs/autofs4/symlink.c +9 -4
@@ -12,10 +12,15 @@#include "autofs_i.h" -static const char *autofs4_follow_link (struct dentry *dentry,void **cookie) +static const char *autofs4_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct autofs_sb_info *sbi =autofs4_sbi (dentry->d_sb); -struct autofs_info *ino =autofs4_dentry_ino (dentry); +struct autofs_sb_info *sbi; +struct autofs_info *ino; +if (!dentry) +return ERR_PTR (-ECHILD ); + sbi =autofs4_sbi (dentry->d_sb); + ino =autofs4_dentry_ino (dentry);if (ino && !autofs4_oz_mode (sbi)) ino->last_used = jiffies;return d_inode (dentry)->i_private;
@@ -23,5 +28,5 @@ static const char *autofs4_follow_link(struct dentry *dentry, void **cookie)const struct inode_operations autofs4_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = autofs4_follow_link + .get_link = autofs4_get_link };
fs/btrfs/inode.c +1 -1
@@ -10118,7 +10118,7 @@ static const struct inode_operations btrfs_special_inode_operations = { };static const struct inode_operations btrfs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .getattr = btrfs_getattr, .setattr = btrfs_setattr,
fs/ceph/inode.c +1 -1
@@ -1756,7 +1756,7 @@ retry:*/ static const struct inode_operations ceph_symlink_iops = { .readlink = generic_readlink, - .follow_link = simple_follow_link, + .get_link = simple_get_link, .setattr = ceph_setattr, .getattr = ceph_getattr, .setxattr = ceph_setxattr,
fs/cifs/cifsfs.c +1 -1
@@ -900,7 +900,7 @@ const struct inode_operations cifs_file_inode_ops = {const struct inode_operations cifs_symlink_inode_ops = { .readlink = generic_readlink, - .follow_link = cifs_follow_link, + .get_link = cifs_get_link, .put_link = kfree_put_link, .permission = cifs_permission,/* BB add the following two eventually */
fs/cifs/cifsfs.h +1 -3
@@ -120,9 +120,7 @@ extern struct vfsmount *cifs_dfs_d_automount(struct path *path);#endif /* Functions related to symlinks */ -extern const char *cifs_follow_link (struct dentry *direntry,void **cookie); -extern int cifs_readlink (struct dentry *direntry,char __user *buffer, -int buflen); +extern const char *cifs_get_link (struct dentry *,struct inode *,void **);extern int cifs_symlink (struct inode *inode,struct dentry *direntry,const char *symname);extern int cifs_removexattr (struct dentry *,const char *);
fs/cifs/link.c +4 -2
@@ -627,9 +627,8 @@ cifs_hl_exit: }const char * -cifs_follow_link (struct dentry *direntry,void **cookie) +cifs_get_link (struct dentry *direntry,struct inode *inode,void **cookie) { -struct inode *inode =d_inode (direntry);int rc = -ENOMEM ;unsigned int xid;char *full_path =NULL ;
@@ -639,6 +638,9 @@ cifs_follow_link(struct dentry *direntry, void **cookie)struct cifs_tcon *tcon;struct TCP_Server_Info *server; +if (!direntry) +return ERR_PTR (-ECHILD ); + xid =get_xid (); tlink =cifs_sb_tlink (cifs_sb);
fs/coda/cnode.c +1 -1
@@ -17,7 +17,7 @@ static inline int coda_fideq(struct CodaFid *fid1, struct CodaFid *fid2)static const struct inode_operations coda_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .setattr = coda_setattr, };
fs/configfs/symlink.c +8 -3
@@ -279,11 +279,16 @@ static int configfs_getlink(struct dentry *dentry, char * path) } -static const char *configfs_follow_link (struct dentry *dentry,void **cookie) +static const char *configfs_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -unsigned long page =get_zeroed_page (GFP_KERNEL ); +unsigned long page;int error; +if (!dentry) +return ERR_PTR (-ECHILD ); + + page =get_zeroed_page (GFP_KERNEL );if (!page)return ERR_PTR (-ENOMEM );
@@ -297,7 +302,7 @@ static const char *configfs_follow_link(struct dentry *dentry, void **cookie) }const struct inode_operations configfs_symlink_inode_operations = { - .follow_link = configfs_follow_link, + .get_link = configfs_get_link, .readlink = generic_readlink, .put_link = free_page_put_link, .setattr = configfs_setattr,
fs/dcache.c +1 -1
@@ -1734,7 +1734,7 @@ static unsigned d_flags_for_inode(struct inode *inode) }if (unlikely (!(inode->i_opflags &IOP_NOFOLLOW ))) { -if (unlikely (inode->i_op->follow_link)) { +if (unlikely (inode->i_op->get_link)) { add_flags =DCACHE_SYMLINK_TYPE ; goto type_determined; }
fs/ecryptfs/inode.c +9 -3
@@ -674,10 +674,16 @@ out:return rc ?ERR_PTR (rc) : buf; } -static const char *ecryptfs_follow_link (struct dentry *dentry,void **cookie) +static const char *ecryptfs_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) {size_t len; -char *buf =ecryptfs_readlink_lower (dentry, &len); +char *buf; + +if (!dentry) +return ERR_PTR (-ECHILD ); + + buf =ecryptfs_readlink_lower (dentry, &len);if (IS_ERR (buf))return buf; fsstack_copy_attr_atime(d_inode(dentry),
@@ -1095,7 +1101,7 @@ out:const struct inode_operations ecryptfs_symlink_iops = { .readlink = generic_readlink, - .follow_link = ecryptfs_follow_link, + .get_link = ecryptfs_get_link, .put_link = kfree_put_link, .permission = ecryptfs_permission, .setattr = ecryptfs_setattr,
fs/ext2/symlink.c +2 -2
@@ -22,7 +22,7 @@const struct inode_operations ext2_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .setattr = ext2_setattr, #ifdef CONFIG_EXT2_FS_XATTR
@@ -35,7 +35,7 @@ const struct inode_operations ext2_symlink_inode_operations = {const struct inode_operations ext2_fast_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = simple_follow_link, + .get_link = simple_get_link, .setattr = ext2_setattr, #ifdef CONFIG_EXT2_FS_XATTR .setxattr = generic_setxattr,
fs/ext4/symlink.c +8 -5
@@ -23,17 +23,20 @@#include "xattr.h" #ifdef CONFIG_EXT4_FS_ENCRYPTION -static const char *ext4_encrypted_follow_link (struct dentry *dentry,void **cookie) +static const char *ext4_encrypted_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) {struct page *cpage =NULL ;char *caddr, *paddr =NULL ;struct ext4_str cstr, pstr; -struct inode *inode =d_inode (dentry);struct ext4_encrypted_symlink_data *sd;loff_t size =min_t (loff_t,i_size_read (inode),PAGE_SIZE -1 );int res;u32 plen, max_size = inode->i_sb->s_blocksize; +if (!dentry) +return ERR_PTR (-ECHILD ); + res =ext4_get_encryption_info (inode);if (res)return ERR_PTR (res);
@@ -87,7 +90,7 @@ errout:const struct inode_operations ext4_encrypted_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = ext4_encrypted_follow_link, + .get_link = ext4_encrypted_get_link, .put_link = kfree_put_link, .setattr = ext4_setattr, .setxattr = generic_setxattr,
@@ -99,7 +102,7 @@ const struct inode_operations ext4_encrypted_symlink_inode_operations = {const struct inode_operations ext4_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .setattr = ext4_setattr, .setxattr = generic_setxattr,
@@ -110,7 +113,7 @@ const struct inode_operations ext4_symlink_inode_operations = {const struct inode_operations ext4_fast_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = simple_follow_link, + .get_link = simple_get_link, .setattr = ext4_setattr, .setxattr = generic_setxattr, .getxattr = generic_getxattr,
fs/f2fs/namei.c +10 -6
@@ -315,9 +315,10 @@ fail:return err; } -static const char *f2fs_follow_link (struct dentry *dentry,void **cookie) +static const char *f2fs_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -const char *link =page_follow_link_light (dentry, cookie); +const char *link =page_get_link (dentry, inode, cookie);if (!IS_ERR (link) && !*link) {/* this is broken symlink case */ page_put_link (NULL , *cookie);
@@ -924,18 +925,21 @@ static int f2fs_rename2(struct inode *old_dir, struct dentry *old_dentry, }#ifdef CONFIG_F2FS_FS_ENCRYPTION -static const char *f2fs_encrypted_follow_link (struct dentry *dentry,void **cookie) +static const char *f2fs_encrypted_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) {struct page *cpage =NULL ;char *caddr, *paddr =NULL ;struct f2fs_str cstr;struct f2fs_str pstr =FSTR_INIT (NULL ,0 ); -struct inode *inode =d_inode (dentry);struct f2fs_encrypted_symlink_data *sd;loff_t size =min_t (loff_t,i_size_read (inode),PAGE_SIZE -1 );u32 max_size = inode->i_sb->s_blocksize;int res; +if (!dentry) +return ERR_PTR (-ECHILD ); + res =f2fs_get_encryption_info (inode);if (res)return ERR_PTR (res);
@@ -994,7 +998,7 @@ errout:const struct inode_operations f2fs_encrypted_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = f2fs_encrypted_follow_link, + .get_link = f2fs_encrypted_get_link, .put_link = kfree_put_link, .getattr = f2fs_getattr, .setattr = f2fs_setattr,
@@ -1030,7 +1034,7 @@ const struct inode_operations f2fs_dir_inode_operations = {const struct inode_operations f2fs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = f2fs_follow_link, + .get_link = f2fs_get_link, .put_link = page_put_link, .getattr = f2fs_getattr, .setattr = f2fs_setattr,
fs/fuse/dir.c +6 -3
@@ -1365,14 +1365,17 @@ static int fuse_readdir(struct file *file, struct dir_context *ctx)return err; } -static const char *fuse_follow_link (struct dentry *dentry,void **cookie) +static const char *fuse_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct inode *inode =d_inode (dentry);struct fuse_conn *fc =get_fuse_conn (inode);FUSE_ARGS (args);char *link;ssize_t ret; +if (!dentry) +return ERR_PTR (-ECHILD ); + link = (char *)__get_free_page (GFP_KERNEL );if (!link)return ERR_PTR (-ENOMEM );
@@ -1909,7 +1912,7 @@ static const struct inode_operations fuse_common_inode_operations = {static const struct inode_operations fuse_symlink_inode_operations = { .setattr = fuse_setattr, - .follow_link = fuse_follow_link, + .get_link = fuse_get_link, .put_link = free_page_put_link, .readlink = generic_readlink, .getattr = fuse_getattr,
fs/gfs2/inode.c +10 -5
@@ -1712,24 +1712,29 @@ static int gfs2_rename2(struct inode *odir, struct dentry *odentry, }/** -* gfs2_follow_link - Follow a symbolic link +* gfs2_get_link - Follow a symbolic link * @dentry: The dentry of the link -* @nd: Data that we pass to vfs_follow_link() +* @inode: The inode of the link +* @cookie: place to store the information for ->put_link() * * This can handle symlinks of any size. * * Returns: 0 on success or error code */ -static const char *gfs2_follow_link (struct dentry *dentry,void **cookie) +static const char *gfs2_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct gfs2_inode *ip =GFS2_I (d_inode (dentry)); +struct gfs2_inode *ip =GFS2_I (inode);struct gfs2_holder i_gh;struct buffer_head *dibh;unsigned int size;char *buf;int error; +if (!dentry) +return ERR_PTR (-ECHILD ); +gfs2_holder_init (ip->i_gl,LM_ST_SHARED ,0 , &i_gh); error =gfs2_glock_nq (&i_gh);if (error) {
@@ -2132,7 +2137,7 @@ const struct inode_operations gfs2_dir_iops = {const struct inode_operations gfs2_symlink_iops = { .readlink = generic_readlink, - .follow_link = gfs2_follow_link, + .get_link = gfs2_get_link, .put_link = kfree_put_link, .permission = gfs2_permission, .setattr = gfs2_setattr,
fs/hostfs/hostfs_kern.c +7 -3
@@ -892,9 +892,13 @@ static const struct inode_operations hostfs_dir_iops = { .setattr = hostfs_setattr, }; -static const char *hostfs_follow_link (struct dentry *dentry,void **cookie) +static const char *hostfs_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -char *link =__getname (); +char *link; +if (!dentry) +return ERR_PTR (-ECHILD ); + link =__getname ();if (link) {char *path =dentry_name (dentry);int err = -ENOMEM ;
@@ -922,7 +926,7 @@ static void hostfs_put_link(struct inode *unused, void *cookie)static const struct inode_operations hostfs_link_iops = { .readlink = generic_readlink, - .follow_link = hostfs_follow_link, + .get_link = hostfs_get_link, .put_link = hostfs_put_link, };
fs/jffs2/symlink.c +1 -1
@@ -14,7 +14,7 @@const struct inode_operations jffs2_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = simple_follow_link, + .get_link = simple_get_link, .setattr = jffs2_setattr, .setxattr = jffs2_setxattr, .getxattr = jffs2_getxattr,
fs/jfs/symlink.c +2 -2
@@ -23,7 +23,7 @@const struct inode_operations jfs_fast_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = simple_follow_link, + .get_link = simple_get_link, .setattr = jfs_setattr, .setxattr = jfs_setxattr, .getxattr = jfs_getxattr,
@@ -33,7 +33,7 @@ const struct inode_operations jfs_fast_symlink_inode_operations = {const struct inode_operations jfs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .setattr = jfs_setattr, .setxattr = jfs_setxattr,
fs/kernfs/symlink.c +8 -3
@@ -112,10 +112,15 @@ static int kernfs_getlink(struct dentry *dentry, char *path)return error; } -static const char *kernfs_iop_follow_link (struct dentry *dentry,void **cookie) +static const char *kernfs_iop_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) {int error = -ENOMEM ; -unsigned long page =get_zeroed_page (GFP_KERNEL ); +unsigned long page; + +if (!dentry) +return ERR_PTR (-ECHILD ); + page =get_zeroed_page (GFP_KERNEL );if (!page)return ERR_PTR (-ENOMEM ); error =kernfs_getlink (dentry, (char *)page);
@@ -132,7 +137,7 @@ const struct inode_operations kernfs_symlink_iops = { .getxattr = kernfs_iop_getxattr, .listxattr = kernfs_iop_listxattr, .readlink = generic_readlink, - .follow_link = kernfs_iop_follow_link, + .get_link = kernfs_iop_get_link, .put_link = free_page_put_link, .setattr = kernfs_iop_setattr, .getattr = kernfs_iop_getattr,
fs/libfs.c +5 -4
@@ -1092,14 +1092,15 @@ simple_nosetlease(struct file *filp, long arg, struct file_lock **flp, }EXPORT_SYMBOL (simple_nosetlease); -const char *simple_follow_link (struct dentry *dentry,void **cookie) +const char *simple_get_link (struct dentry *dentry,struct inode *inode, +void **cookie) { -return d_inode (dentry)->i_link; +return inode->i_link; } -EXPORT_SYMBOL (simple_follow_link); +EXPORT_SYMBOL (simple_get_link);const struct inode_operations simple_symlink_inode_operations = { - .follow_link = simple_follow_link, + .get_link = simple_get_link, .readlink = generic_readlink };EXPORT_SYMBOL (simple_symlink_inode_operations);
fs/minix/inode.c +1 -1
@@ -435,7 +435,7 @@ static const struct address_space_operations minix_aops = {static const struct inode_operations minix_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .getattr = minix_getattr, };
fs/namei.c +28 -17
100 lines not on this page · raw message
fs/ncpfs/inode.c +1 -1
@@ -244,7 +244,7 @@ static void ncp_set_attr(struct inode *inode, struct ncp_entry_info *nwinfo)#if defined(CONFIG_NCPFS_EXTRAS ) || defined(CONFIG_NCPFS_NFS_NS )static const struct inode_operations ncp_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .setattr = ncp_notify_change, };
fs/nfs/symlink.c +6 -3
@@ -42,12 +42,15 @@ error:return -EIO ; } -static const char *nfs_follow_link (struct dentry *dentry,void **cookie) +static const char *nfs_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct inode *inode =d_inode (dentry);struct page *page;void *err; +if (!dentry) +return ERR_PTR (-ECHILD ); + err =ERR_PTR (nfs_revalidate_mapping (inode, inode->i_mapping));if (err)return err;
@@ -64,7 +67,7 @@ static const char *nfs_follow_link(struct dentry *dentry, void **cookie)*/ const struct inode_operations nfs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = nfs_follow_link, + .get_link = nfs_get_link, .put_link = page_put_link, .getattr = nfs_getattr, .setattr = nfs_setattr,
fs/nilfs2/namei.c +1 -1
@@ -569,7 +569,7 @@ const struct inode_operations nilfs_special_inode_operations = {const struct inode_operations nilfs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .permission = nilfs_permission, };
fs/ocfs2/symlink.c +1 -1
@@ -88,7 +88,7 @@ const struct address_space_operations ocfs2_fast_symlink_aops = {const struct inode_operations ocfs2_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .getattr = ocfs2_getattr, .setattr = ocfs2_setattr,
fs/overlayfs/inode.c +8 -4
@@ -140,17 +140,21 @@ struct ovl_link_data {void *cookie; }; -static const char *ovl_follow_link (struct dentry *dentry,void **cookie) +static const char *ovl_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) {struct dentry *realdentry;struct inode *realinode;struct ovl_link_data *data =NULL ;const char *ret; +if (!dentry) +return ERR_PTR (-ECHILD ); + realdentry =ovl_dentry_real (dentry); realinode = realdentry->d_inode; -if (WARN_ON (!realinode->i_op->follow_link)) +if (WARN_ON (!realinode->i_op->get_link))return ERR_PTR (-EPERM );if (realinode->i_op->put_link) {
@@ -160,7 +164,7 @@ static const char *ovl_follow_link(struct dentry *dentry, void **cookie) data->realdentry = realdentry; } - ret = realinode->i_op->follow_link (realdentry, cookie); + ret = realinode->i_op->get_link (realdentry, realinode, cookie);if (IS_ERR_OR_NULL (ret)) {kfree (data);return ret;
@@ -381,7 +385,7 @@ static const struct inode_operations ovl_file_inode_operations = {static const struct inode_operations ovl_symlink_inode_operations = { .setattr = ovl_setattr, - .follow_link = ovl_follow_link, + .get_link = ovl_get_link, .put_link = ovl_put_link, .readlink = ovl_readlink, .getattr = ovl_getattr,
fs/proc/base.c +13 -9
@@ -1564,12 +1564,15 @@ static int proc_exe_link(struct dentry *dentry, struct path *exe_path)return -ENOENT ; } -static const char *proc_pid_follow_link (struct dentry *dentry,void **cookie) +static const char *proc_pid_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct inode *inode =d_inode (dentry);struct path path;int error = -EACCES ; +if (!dentry) +return ERR_PTR (-ECHILD ); +/* Are we allowed to snoop on the tasks file descriptors? */ if (!proc_fd_access_allowed (inode)) goto out;
@@ -1630,7 +1633,7 @@ out:const struct inode_operations proc_pid_link_inode_operations = { .readlink = proc_pid_readlink, - .follow_link = proc_pid_follow_link, + .get_link = proc_pid_get_link, .setattr = proc_setattr, };
@@ -1895,7 +1898,7 @@ static const struct dentry_operations tid_map_files_dentry_operations = { .d_delete = pid_delete_dentry, }; -static int proc_map_files_get_link (struct dentry *dentry,struct path *path) +static int map_files_get_link (struct dentry *dentry,struct path *path) {unsigned long vm_start, vm_end;struct vm_area_struct *vma;
@@ -1945,20 +1948,21 @@ struct map_files_info {* path to the file in question. */ static const char * -proc_map_files_follow_link (struct dentry *dentry,void **cookie) +proc_map_files_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) {if (!capable (CAP_SYS_ADMIN ))return ERR_PTR (-EPERM ); -return proc_pid_follow_link (dentry,NULL ); +return proc_pid_get_link (dentry, inode,NULL ); }/* -* Identical to proc_pid_link_inode_operations except for follow_link() +* Identical to proc_pid_link_inode_operations except for get_link() */ static const struct inode_operations proc_map_files_link_inode_operations = { .readlink = proc_pid_readlink, - .follow_link = proc_map_files_follow_link, + .get_link = proc_map_files_get_link, .setattr = proc_setattr, };
@@ -1975,7 +1979,7 @@ proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,return -ENOENT ; ei =PROC_I (inode); - ei->op.proc_get_link = proc_map_files_get_link; + ei->op.proc_get_link = map_files_get_link; inode->i_op = &proc_map_files_link_inode_operations; inode->i_size =64 ;
fs/proc/inode.c +4 -3
@@ -393,9 +393,10 @@ static const struct file_operations proc_reg_file_ops_no_compat = { };#endif -static const char *proc_follow_link (struct dentry *dentry,void **cookie) +static const char *proc_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct proc_dir_entry *pde =PDE (d_inode (dentry)); +struct proc_dir_entry *pde =PDE (inode);if (unlikely (!use_pde (pde)))return ERR_PTR (-EINVAL ); *cookie = pde;
@@ -409,7 +410,7 @@ static void proc_put_link(struct inode *unused, void *p)const struct inode_operations proc_link_inode_operations = { .readlink = generic_readlink, - .follow_link = proc_follow_link, + .get_link = proc_get_link, .put_link = proc_put_link, };
fs/proc/namespaces.c +6 -3
@@ -30,14 +30,17 @@ static const struct proc_ns_operations *ns_entries[] = { &mntns_operations, }; -static const char *proc_ns_follow_link (struct dentry *dentry,void **cookie) +static const char *proc_ns_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct inode *inode =d_inode (dentry);const struct proc_ns_operations *ns_ops =PROC_I (inode)->ns_ops;struct task_struct *task;struct path ns_path;void *error =ERR_PTR (-EACCES ); +if (!dentry) +return ERR_PTR (-ECHILD ); + task =get_proc_task (inode);if (!task)return error;
@@ -74,7 +77,7 @@ static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflstatic const struct inode_operations proc_ns_link_inode_operations = { .readlink = proc_ns_readlink, - .follow_link = proc_ns_follow_link, + .get_link = proc_ns_get_link, .setattr = proc_setattr, };
fs/proc/self.c +5 -2
@@ -18,12 +18,15 @@ static int proc_self_readlink(struct dentry *dentry, char __user *buffer,return readlink_copy (buffer, buflen, tmp); } -static const char *proc_self_follow_link (struct dentry *dentry,void **cookie) +static const char *proc_self_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) {struct pid_namespace *ns = dentry->d_sb->s_fs_info;pid_t tgid =task_tgid_nr_ns (current, ns);char *name; +if (!dentry) +return ERR_PTR (-ECHILD );if (!tgid)return ERR_PTR (-ENOENT );/* 11 for max length of signed int in decimal + NULL term */
@@ -36,7 +39,7 @@ static const char *proc_self_follow_link(struct dentry *dentry, void **cookie)static const struct inode_operations proc_self_inode_operations = { .readlink = proc_self_readlink, - .follow_link = proc_self_follow_link, + .get_link = proc_self_get_link, .put_link = kfree_put_link, };
fs/proc/thread_self.c +5 -2
@@ -19,13 +19,16 @@ static int proc_thread_self_readlink(struct dentry *dentry, char __user *buffer,return readlink_copy (buffer, buflen, tmp); } -static const char *proc_thread_self_follow_link (struct dentry *dentry,void **cookie) +static const char *proc_thread_self_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) {struct pid_namespace *ns = dentry->d_sb->s_fs_info;pid_t tgid =task_tgid_nr_ns (current, ns);pid_t pid =task_pid_nr_ns (current, ns);char *name; +if (!dentry) +return ERR_PTR (-ECHILD );if (!pid)return ERR_PTR (-ENOENT ); name =kmalloc (PROC_NUMBUF +6 +PROC_NUMBUF ,GFP_KERNEL );
@@ -37,7 +40,7 @@ static const char *proc_thread_self_follow_link(struct dentry *dentry, void **costatic const struct inode_operations proc_thread_self_inode_operations = { .readlink = proc_thread_self_readlink, - .follow_link = proc_thread_self_follow_link, + .get_link = proc_thread_self_get_link, .put_link = kfree_put_link, };
fs/reiserfs/namei.c +1 -1
@@ -1665,7 +1665,7 @@ const struct inode_operations reiserfs_dir_inode_operations = {*/ const struct inode_operations reiserfs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .setattr = reiserfs_setattr, .setxattr = reiserfs_setxattr,
fs/squashfs/symlink.c +1 -1
@@ -119,7 +119,7 @@ const struct address_space_operations squashfs_symlink_aops = {const struct inode_operations squashfs_symlink_inode_ops = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .getxattr = generic_getxattr, .listxattr = squashfs_listxattr
fs/sysv/inode.c +1 -1
@@ -146,7 +146,7 @@ static inline void write3byte(struct sysv_sb_info *sbi,static const struct inode_operations sysv_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .getattr = sysv_getattr, };
fs/ubifs/file.c +1 -1
@@ -1608,7 +1608,7 @@ const struct inode_operations ubifs_file_inode_operations = {const struct inode_operations ubifs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = simple_follow_link, + .get_link = simple_get_link, .setattr = ubifs_setattr, .getattr = ubifs_getattr, .setxattr = ubifs_setxattr,
fs/xfs/xfs_iops.c +6 -2
@@ -414,13 +414,17 @@ xfs_vn_rename(* uio is kmalloced for this reason... */ STATIC const char * -xfs_vn_follow_link ( +xfs_vn_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) {char *link;int error = -ENOMEM ; +if (!dentry) +return ERR_PTR (-ECHILD ); + link =kmalloc (MAXPATHLEN +1 ,GFP_KERNEL );if (!link) goto out_err;
@@ -1172,7 +1176,7 @@ static const struct inode_operations xfs_dir_ci_inode_operations = {static const struct inode_operations xfs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = xfs_vn_follow_link, + .get_link = xfs_vn_get_link, .put_link = kfree_put_link, .getattr = xfs_vn_getattr, .setattr = xfs_vn_setattr,
include/linux/fs.h +3 -3
@@ -1633,7 +1633,7 @@ struct file_operations {struct inode_operations {struct dentry * (*lookup) (struct inode *,struct dentry *,unsigned int ); -const char * (*follow_link) (struct dentry *,void **); +const char * (*get_link) (struct dentry *,struct inode *,void **);int (*permission) (struct inode *,int );struct posix_acl * (*get_acl)(struct inode *,int );
@@ -2736,7 +2736,7 @@ extern const struct file_operations generic_ro_fops;extern int readlink_copy (char __user *,int ,const char *);extern int page_readlink (struct dentry *,char __user *,int ); -extern const char *page_follow_link_light (struct dentry *,void **); +extern const char *page_get_link (struct dentry *,struct inode *,void **);extern void page_put_link (struct inode *,void *);extern int __page_symlink (struct inode *inode,const char *symname,int len,int nofs);
@@ -2754,7 +2754,7 @@ void __inode_sub_bytes(struct inode *inode, loff_t bytes);void inode_sub_bytes (struct inode *inode,loff_t bytes);loff_t inode_get_bytes (struct inode *inode);void inode_set_bytes (struct inode *inode,loff_t bytes); -const char *simple_follow_link (struct dentry *,void **); +const char *simple_get_link (struct dentry *,struct inode *,void **);extern const struct inode_operations simple_symlink_inode_operations;extern int iterate_dir (struct file *,struct dir_context *);
mm/shmem.c +8 -4
@@ -2496,10 +2496,14 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *sreturn 0 ; } -static const char *shmem_follow_link (struct dentry *dentry,void **cookie) +static const char *shmem_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) {struct page *page =NULL ; -int error =shmem_getpage (d_inode (dentry),0 , &page,SGP_READ ,NULL ); +int error; +if (!dentry) +return ERR_PTR (-ECHILD ); + error =shmem_getpage (inode,0 , &page,SGP_READ ,NULL );if (error)return ERR_PTR (error);unlock_page (page);
@@ -2656,7 +2660,7 @@ static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size)static const struct inode_operations shmem_short_symlink_operations = { .readlink = generic_readlink, - .follow_link = simple_follow_link, + .get_link = simple_get_link, #ifdef CONFIG_TMPFS_XATTR .setxattr = shmem_setxattr, .getxattr = shmem_getxattr,
@@ -2667,7 +2671,7 @@ static const struct inode_operations shmem_short_symlink_operations = {static const struct inode_operations shmem_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = shmem_follow_link, + .get_link = shmem_get_link, .put_link = shmem_put_link, #ifdef CONFIG_TMPFS_XATTR .setxattr = shmem_setxattr,
Signature · 1 line
2.1.4
Al Viro
maintainerPATCH 8/10 teach page_get_link() to work in RCU mode
In reply to Al ViroFrom: Al Viro <[email protected]>
more or less along the lines of Neil's patchset, sans the insanity around kmap().
Signed-off-by Al Viro <[email protected]>
--- fs/namei.c | 19 +++++++++++++------ fs/proc/self.c | 2 +- fs/proc/thread_self.c | 2 +- 3 files changed, 15 insertions(+), 8 deletions(-)
fs/namei.c +13 -6
@@ -4534,12 +4534,19 @@ const char *page_get_link(struct dentry *dentry, struct inode *inode,struct page *page;struct address_space *mapping = inode->i_mapping; -if (!dentry) -return ERR_PTR (-ECHILD ); - - page =read_mapping_page (mapping,0 ,NULL ); -if (IS_ERR (page)) -return (char *)page; +if (!dentry) { + page =find_get_page (mapping,0 ); +if (!page) +return ERR_PTR (-ECHILD ); +if (!PageUptodate (page)) { +put_page (page); +return ERR_PTR (-ECHILD ); + } + }else { + page =read_mapping_page (mapping,0 ,NULL ); +if (IS_ERR (page)) +return (char *)page; + } *cookie = page;BUG_ON (mapping_gfp_mask (mapping) & __GFP_HIGHMEM); kaddr =page_address (page);
fs/proc/self.c +1 -1
@@ -21,7 +21,7 @@ static int proc_self_readlink(struct dentry *dentry, char __user *buffer,static const char *proc_self_get_link (struct dentry *dentry,struct inode *inode,void **cookie) { -struct pid_namespace *ns = dentry->d_sb->s_fs_info; +struct pid_namespace *ns = inode->i_sb->s_fs_info;pid_t tgid =task_tgid_nr_ns (current, ns);char *name;
fs/proc/thread_self.c +1 -1
@@ -22,7 +22,7 @@ static int proc_thread_self_readlink(struct dentry *dentry, char __user *buffer,static const char *proc_thread_self_get_link (struct dentry *dentry,struct inode *inode,void **cookie) { -struct pid_namespace *ns = dentry->d_sb->s_fs_info; +struct pid_namespace *ns = inode->i_sb->s_fs_info;pid_t tgid =task_tgid_nr_ns (current, ns);pid_t pid =task_pid_nr_ns (current, ns);char *name;
Signature · 1 line
2.1.4
Al Viro
maintainerPATCH 9/10 teach shmem_get_link() to work in RCU mode
In reply to Al ViroFrom: Al Viro <[email protected]>
Signed-off-by Al Viro <[email protected]>
--- mm/shmem.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-)
mm/shmem.c +14 -6
@@ -2501,12 +2501,20 @@ static const char *shmem_get_link(struct dentry *dentry, {struct page *page =NULL ;int error; -if (!dentry) -return ERR_PTR (-ECHILD ); - error =shmem_getpage (inode,0 , &page,SGP_READ ,NULL ); -if (error) -return ERR_PTR (error); -unlock_page (page); +if (!dentry) { + page =find_get_page (inode->i_mapping,0 ); +if (!page) +return ERR_PTR (-ECHILD ); +if (!PageUptodate (page)) { +put_page (page); +return ERR_PTR (-ECHILD ); + } + }else { + error =shmem_getpage (inode,0 , &page,SGP_READ ,NULL ); +if (error) +return ERR_PTR (error); +unlock_page (page); + } *cookie = page;return page_address (page); }
Signature · 1 line
2.1.4
Al Viro
maintainerPATCH 10/10 teach proc_self_get_link()/proc_thread_self_get_link() to work in RCU mode
In reply to Al ViroFrom: Al Viro <[email protected]>
Signed-off-by Al Viro <[email protected]>
--- fs/proc/self.c | 8 +++----- fs/proc/thread_self.c | 9 ++++----- 2 files changed, 7 insertions(+), 10 deletions(-)
fs/proc/self.c +3 -5
@@ -25,14 +25,12 @@ static const char *proc_self_get_link(struct dentry *dentry,pid_t tgid =task_tgid_nr_ns (current, ns);char *name; -if (!dentry) -return ERR_PTR (-ECHILD );if (!tgid)return ERR_PTR (-ENOENT );/* 11 for max length of signed int in decimal + NULL term */ - name =kmalloc (12 ,GFP_KERNEL ); -if (!name) -return ERR_PTR (-ENOMEM ); + name =kmalloc (12 , dentry ?GFP_KERNEL :GFP_ATOMIC ); +if (unlikely (!name)) +return dentry ?ERR_PTR (-ENOMEM ) :ERR_PTR (-ECHILD );sprintf (name,"%d" , tgid);return *cookie = name; }
fs/proc/thread_self.c +4 -5
@@ -27,13 +27,12 @@ static const char *proc_thread_self_get_link(struct dentry *dentry,pid_t pid =task_pid_nr_ns (current, ns);char *name; -if (!dentry) -return ERR_PTR (-ECHILD );if (!pid)return ERR_PTR (-ENOENT ); - name =kmalloc (PROC_NUMBUF +6 +PROC_NUMBUF ,GFP_KERNEL ); -if (!name) -return ERR_PTR (-ENOMEM ); + name =kmalloc (PROC_NUMBUF +6 +PROC_NUMBUF , + dentry ?GFP_KERNEL :GFP_ATOMIC ); +if (unlikely (!name)) +return dentry ?ERR_PTR (-ENOMEM ) :ERR_PTR (-ECHILD );sprintf (name,"%d/task/%d" , tgid, pid);return *cookie = name; }
Signature · 1 line
2.1.4
Al Viro
maintainerPATCH v2 1/1 ->follow_link() without dropping from RCU mode
In reply to Al ViroQuoted 7 lines · Al Viro
Right now we stay in RCU mode for fast symlink traversal.
However, anything trickier drops out of RCU mode - back in 4.2 the symlink-related pile had grown too large to add this on top of everything else. Below is an attempt to do that now.Those who prefer to use git for review can find that series in git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git work.symlinks
Compared to the previous iteration:
* rebased to 4.4-rc4.
* NFS (in case of pagecache hit, of course) also stays in RCU mode.
* renamed inode_nohigh() as suggested by dchinner, moved tofs/inode.c - less header PITA that way.
What's there:
01/11: switch befs long symlinks to page_symlink_operations 02/11: logfs: don't duplicate page_symlink_inode_operations 03/11: udf: don't duplicate page_symlink_inode_operations
04/11: ufs: get rid of ->setattr() for symlinks
Simplifying things a bit by switching them to page_symlink_operations
where possible.
05/11: namei: page_getlink() and page_follow_link_light() are the same thing
Get rid of some code duplication
06/11: don't put symlink bodies in pagecache into highmem
Bugfix for a long-standing mess. For pagecache-based symlinks we end
up with kmap() of the body for the duration of traversal. Which could take a long time if we walk into e.g. slow automount along the way. It's DoSable, actually. Not hard to fix - there's no reason to use GFP_HIGHUSER_MOVABLE for those guys; GFP_USER serves just as well.
07/11: replace ->follow_link() with new method that could stay
Meat of the series - we switch to a new method (->get_link()) that
differs from ->follow_link() in getting dentry and inode separately; it can be called in RCU mode (with NULL dentry) and it should bail out with ERR_PTR(-ECHILD) if it needs non-RCU. All instances converted, most of them by making them bail out immediately in RCU mode. Some are trivialy RCU-safe, though; those do not bail out at all.
08/11: teach page_get_link() to work in RCU mode
09/11: teach shmem_get_link() to work in RCU mode
10/11: teach proc_self_get_link()/proc_thread_self_get_link() 11/11: teach nfs_get_link() to work in RCU mode
Teaching more instances to stay in RCU mode if they can. (8) and
(11) are similar to what Neil had done back in March, except for the lack of kmap mess to deal with - that's one of the benefits of having (6) done...
Missing, probably worth adding: XFS, overlayfs. Maybe gfs2 - if it's
at all possible (not sure if it is). Maybe autofs4 as well.
Procfs magical symlinks definitely are *not* worth trying to handle
in RCU mode - ->d_revalidate() on them is such that it'll kick us out of RCU mode before we even see that it's a symlink, let alone try to follow it.
Any help with review and testing would be welcome. FWIW, it seems to survive the beating here.
Al Viro
maintainerPATCH v2 1/11 switch befs long symlinks to page_symlink_operations
From: Al Viro <[email protected]>
just give them the right ->readpage()...
Signed-off-by Al Viro <[email protected]>
--- fs/befs/linuxvfs.c | 41 ++++++++++++++++++++++------------------- 1 file changed, 22 insertions(+), 19 deletions(-)
fs/befs/linuxvfs.c +22 -19
@@ -42,7 +42,7 @@ static struct inode *befs_iget(struct super_block *, unsigned long);static struct inode *befs_alloc_inode (struct super_block *sb);static void befs_destroy_inode (struct inode *inode);static void befs_destroy_inodecache (void ); -static const char *befs_follow_link (struct dentry *,void **); +static int befs_symlink_readpage (struct file *,struct page *);static int befs_utf2nls (struct super_block *sb,const char *in,int in_len,char **out,int *out_len); static int befs_nls2utf(struct super_block *sb, const char *in, int in_len,
@@ -79,10 +79,8 @@ static const struct address_space_operations befs_aops = { .bmap = befs_bmap, }; -static const struct inode_operations befs_symlink_inode_operations = { - .readlink = generic_readlink, - .follow_link = befs_follow_link, - .put_link = kfree_put_link, +static const struct address_space_operations befs_symlink_aops = { + .readpage = befs_symlink_readpage, };/*
@@ -398,7 +396,8 @@ static struct inode *befs_iget(struct super_block *sb, unsigned long ino) inode->i_fop = &befs_dir_operations; }else if (S_ISLNK (inode->i_mode)) {if (befs_ino->i_flags &BEFS_LONG_SYMLINK ) { - inode->i_op = &befs_symlink_inode_operations; + inode->i_op = &page_symlink_inode_operations; + inode->i_mapping->a_ops = &befs_symlink_aops; }else { inode->i_link = befs_ino->i_data.symlink; inode->i_op = &simple_symlink_inode_operations;
@@ -463,31 +462,35 @@ befs_destroy_inodecache(void)* The data stream become link name. Unless the LONG_SYMLINK * flag is set. */ -static const char * -befs_follow_link (struct dentry *dentry,void **cookie) +static int befs_symlink_readpage (struct file *unused,struct page *page) { -struct super_block *sb = dentry->d_sb; -struct befs_inode_info *befs_ino =BEFS_I (d_inode (dentry)); +struct inode *inode = page->mapping->host; +struct super_block *sb = inode->i_sb; +struct befs_inode_info *befs_ino =BEFS_I (inode);befs_data_stream *data = &befs_ino->i_data.ds;befs_off_t len = data->size; -char *link; +char *link =kmap (page); -if (len ==0 ) { +if (len ==0 || len >PAGE_SIZE ) {befs_error (sb,"Long symlink with illegal length" ); -return ERR_PTR (-EIO ); + goto fail; }befs_debug (sb,"Follow long symlink" ); - link =kmalloc (len,GFP_NOFS ); -if (!link) -return ERR_PTR (-ENOMEM );if (befs_read_lsymlink (sb, data, link, len) != len) { -kfree (link);befs_error (sb,"Failed to read entire long symlink" ); -return ERR_PTR (-EIO ); + goto fail; } link[len -1 ] ='\0' ; -return *cookie = link; +SetPageUptodate (page); +kunmap (page); +unlock_page (page); +return 0 ; +fail: +SetPageError (page); +kunmap (page); +unlock_page (page); +return -EIO ; }/*
Signature · 1 line
2.1.4
Al Viro
maintainerPATCH v2 2/11 logfs: don't duplicate page_symlink_inode_operations
In reply to Al ViroFrom: Al Viro <[email protected]>
Signed-off-by Al Viro <[email protected]>
--- fs/logfs/dir.c | 8 +------- fs/logfs/inode.c | 2 +- fs/logfs/logfs.h | 1 - 3 files changed, 2 insertions(+), 9 deletions(-)
fs/logfs/dir.c +1 -7
@@ -528,7 +528,7 @@ static int logfs_symlink(struct inode *dir, struct dentry *dentry,if (IS_ERR (inode))return PTR_ERR (inode); - inode->i_op = &logfs_symlink_iops; + inode->i_op = &page_symlink_inode_operations; inode->i_mapping->a_ops = &logfs_reg_aops;return __logfs_create (dir, dentry, inode, target, destlen);
@@ -776,12 +776,6 @@ fail:return -EIO ; } -const struct inode_operations logfs_symlink_iops = { - .readlink = generic_readlink, - .follow_link = page_follow_link_light, - .put_link = page_put_link, -}; -const struct inode_operations logfs_dir_iops = { .create = logfs_create, .link = logfs_link,
fs/logfs/inode.c +1 -1
@@ -64,7 +64,7 @@ static void logfs_inode_setops(struct inode *inode) inode->i_mapping->a_ops = &logfs_reg_aops;break ;case S_IFLNK : - inode->i_op = &logfs_symlink_iops; + inode->i_op = &page_symlink_inode_operations; inode->i_mapping->a_ops = &logfs_reg_aops;break ;case S_IFSOCK :/* fall through */
fs/logfs/logfs.h +0 -1
@@ -495,7 +495,6 @@ static inline int logfs_get_sb_mtd(struct logfs_super *s, int mtdnr)#endif /* dir.c */ -extern const struct inode_operations logfs_symlink_iops;extern const struct inode_operations logfs_dir_iops;extern const struct file_operations logfs_dir_fops;int logfs_replay_journal (struct super_block *sb);
Signature · 1 line
2.1.4
Al Viro
maintainerPATCH v2 3/11 udf: don't duplicate page_symlink_inode_operations
In reply to Al ViroFrom: Al Viro <[email protected]>
Signed-off-by Al Viro <[email protected]>
--- fs/udf/inode.c | 2 +- fs/udf/namei.c | 7 +------ fs/udf/udfdecl.h | 1 - 3 files changed, 2 insertions(+), 8 deletions(-)
fs/udf/inode.c +1 -1
@@ -1540,7 +1540,7 @@ reread:break ;case ICBTAG_FILE_TYPE_SYMLINK : inode->i_data.a_ops = &udf_symlink_aops; - inode->i_op = &udf_symlink_inode_operations; + inode->i_op = &page_symlink_inode_operations; inode->i_mode =S_IFLNK |S_IRWXUGO ;break ;case ICBTAG_FILE_TYPE_MAIN :
fs/udf/namei.c +1 -6
@@ -921,7 +921,7 @@ static int udf_symlink(struct inode *dir, struct dentry *dentry, } inode->i_data.a_ops = &udf_symlink_aops; - inode->i_op = &udf_symlink_inode_operations; + inode->i_op = &page_symlink_inode_operations;if (iinfo->i_alloc_type !=ICBTAG_FLAG_AD_IN_ICB ) {struct kernel_lb_addr eloc;
@@ -1344,8 +1344,3 @@ const struct inode_operations udf_dir_inode_operations = { .rename = udf_rename, .tmpfile = udf_tmpfile, }; -const struct inode_operations udf_symlink_inode_operations = { - .readlink = generic_readlink, - .follow_link = page_follow_link_light, - .put_link = page_put_link, -};
fs/udf/udfdecl.h +0 -1
@@ -85,7 +85,6 @@ extern const struct inode_operations udf_dir_inode_operations;extern const struct file_operations udf_dir_operations;extern const struct inode_operations udf_file_inode_operations;extern const struct file_operations udf_file_operations; -extern const struct inode_operations udf_symlink_inode_operations;extern const struct address_space_operations udf_aops;extern const struct address_space_operations udf_adinicb_aops;extern const struct address_space_operations udf_symlink_aops;
Signature · 1 line
2.1.4
Al Viro
maintainerPATCH v2 4/11 ufs: get rid of ->setattr() for symlinks
In reply to Al ViroFrom: Al Viro <[email protected]>
It was to needed for a couple of months in 2010, until UFS quota support got dropped. Since then it's equivalent to simple_setattr() (i.e. the default) for everything except the regular files. And dropping it there allows to convert all UFS symlinks to {page,simple}_symlink_inode_operations, getting rid of fs/ufs/symlink.c completely.
Signed-off-by Al Viro <[email protected]>
--- fs/ufs/Makefile | 2 +- fs/ufs/inode.c | 4 ++-- fs/ufs/namei.c | 4 ++-- fs/ufs/symlink.c | 42 ------------------------------------------ fs/ufs/ufs.h | 4 ---- 5 files changed, 5 insertions(+), 51 deletions(-) delete mode 100644 fs/ufs/symlink.c
fs/ufs/Makefile +1 -1
@@ -5,5 +5,5 @@ obj-$(CONFIG_UFS_FS) += ufs.o ufs-objs := balloc.o cylinder.o dir.o file.o ialloc.o inode.o \ - namei.o super.o symlink.o util.o + namei.o super.o util.o ccflags-$(CONFIG_UFS_DEBUG) += -DDEBUG
fs/ufs/inode.c +2 -2
@@ -528,11 +528,11 @@ static void ufs_set_inode_ops(struct inode *inode) inode->i_mapping->a_ops = &ufs_aops; }else if (S_ISLNK (inode->i_mode)) {if (!inode->i_blocks) { - inode->i_op = &ufs_fast_symlink_inode_operations; inode->i_link = (char *)UFS_I (inode)->i_u1.i_symlink; + inode->i_op = &simple_symlink_inode_operations; }else { - inode->i_op = &ufs_symlink_inode_operations; inode->i_mapping->a_ops = &ufs_aops; + inode->i_op = &page_symlink_inode_operations; } }else init_special_inode(inode, inode->i_mode,
fs/ufs/namei.c +2 -2
@@ -123,14 +123,14 @@ static int ufs_symlink (struct inode * dir, struct dentry * dentry,if (l >UFS_SB (sb)->s_uspi->s_maxsymlinklen) {/* slow symlink */ - inode->i_op = &ufs_symlink_inode_operations; + inode->i_op = &page_symlink_inode_operations; inode->i_mapping->a_ops = &ufs_aops; err =page_symlink (inode, symname, l);if (err) goto out_fail; }else {/* fast symlink */ - inode->i_op = &ufs_fast_symlink_inode_operations; + inode->i_op = &simple_symlink_inode_operations; inode->i_link = (char *)UFS_I (inode)->i_u1.i_symlink;memcpy (inode->i_link, symname, l); inode->i_size = l-1 ;
fs/ufs/symlink.c deleted +0 -42
42 lines not on this page · raw message
fs/ufs/ufs.h +0 -4
@@ -136,10 +136,6 @@ extern __printf(3, 4)void ufs_panic (struct super_block *,const char *,const char *, ...);void ufs_mark_sb_dirty (struct super_block *sb); -/* symlink.c */ -extern const struct inode_operations ufs_fast_symlink_inode_operations; -extern const struct inode_operations ufs_symlink_inode_operations; -static inline struct ufs_sb_info *UFS_SB (struct super_block *sb) {return sb->s_fs_info;
Signature · 1 line
2.1.4
Al Viro
maintainerPATCH v2 5/11 namei: page_getlink() and page_follow_link_light() are the same thing
In reply to Al ViroFrom: Al Viro <[email protected]>
Signed-off-by Al Viro <[email protected]>
--- fs/namei.c | 32 +++++++++++++------------------- 1 file changed, 13 insertions(+), 19 deletions(-)
fs/namei.c +13 -19
@@ -4518,7 +4518,7 @@ int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen)EXPORT_SYMBOL (generic_readlink);/* get the link contents into pagecache */ -static char *page_getlink (struct dentry * dentry,struct page **ppage) +static const char *page_getlink (struct dentry * dentry,void **cookie) {char *kaddr;struct page *page;
@@ -4526,31 +4526,15 @@ static char *page_getlink(struct dentry * dentry, struct page **ppage) page =read_mapping_page (mapping,0 ,NULL );if (IS_ERR (page))return (char *)page; - *ppage = page; + *cookie = page; kaddr =kmap (page);nd_terminate_link (kaddr, dentry->d_inode->i_size,PAGE_SIZE -1 );return kaddr; } -int page_readlink (struct dentry *dentry,char __user *buffer,int buflen) -{ -struct page *page =NULL ; -int res =readlink_copy (buffer, buflen,page_getlink (dentry, &page)); -if (page) { -kunmap (page); -page_cache_release (page); - } -return res; -} -EXPORT_SYMBOL (page_readlink); -const char *page_follow_link_light (struct dentry *dentry,void **cookie) { -struct page *page =NULL ; -char *res =page_getlink (dentry, &page); -if (!IS_ERR (res)) - *cookie = page; -return res; +return page_getlink (dentry, cookie); }EXPORT_SYMBOL (page_follow_link_light);
@@ -4562,6 +4546,16 @@ void page_put_link(struct inode *unused, void *cookie) }EXPORT_SYMBOL (page_put_link); +int page_readlink (struct dentry *dentry,char __user *buffer,int buflen) +{ +void *cookie =NULL ; +int res =readlink_copy (buffer, buflen,page_getlink (dentry, &cookie)); +if (cookie) +page_put_link (NULL , cookie); +return res; +} +EXPORT_SYMBOL (page_readlink); +/* * The nofs argument instructs pagecache_write_begin to pass AOP_FLAG_NOFS */
Signature · 1 line
2.1.4
Al Viro
maintainerPATCH v2 6/11 don't put symlink bodies in pagecache into highmem
In reply to Al ViroFrom: Al Viro <[email protected]>
kmap() in page_follow_link_light() needed to go - allowing to hold an arbitrary number of kmaps for long is a great way to deadlocking the system.
new helper (inode_nohighmem(inode)) needs to be used for pagecache symlinks inodes; done for all in-tree cases. page_follow_link_light() instrumented to yell about anything missed.
Signed-off-by Al Viro <[email protected]>
--- Documentation/filesystems/porting | 5 +++++ fs/affs/inode.c | 1 + fs/affs/namei.c | 1 + fs/affs/symlink.c | 4 +--- fs/afs/inode.c | 1 + fs/befs/linuxvfs.c | 5 ++--- fs/btrfs/inode.c | 2 ++ fs/coda/cnode.c | 2 ++ fs/coda/symlink.c | 4 +--- fs/cramfs/inode.c | 1 + fs/efs/inode.c | 1 + fs/efs/symlink.c | 4 +--- fs/exofs/inode.c | 1 + fs/exofs/namei.c | 1 + fs/ext2/inode.c | 1 + fs/ext2/namei.c | 1 + fs/ext4/inode.c | 1 + fs/ext4/namei.c | 1 + fs/ext4/symlink.c | 10 +++------- fs/f2fs/inode.c | 1 + fs/f2fs/namei.c | 5 ++--- fs/freevxfs/vxfs_inode.c | 1 + fs/hfsplus/inode.c | 2 ++ fs/hpfs/inode.c | 1 + fs/hpfs/namei.c | 5 ++--- fs/hugetlbfs/inode.c | 1 + fs/inode.c | 6 ++++++ fs/isofs/inode.c | 1 + fs/isofs/rock.c | 4 +--- fs/jfs/inode.c | 1 + fs/jfs/namei.c | 1 + fs/logfs/dir.c | 1 + fs/logfs/inode.c | 1 + fs/minix/inode.c | 1 + fs/namei.c | 9 +++------ fs/ncpfs/inode.c | 1 + fs/nfs/inode.c | 5 +++-- fs/nfs/symlink.c | 2 +- fs/nilfs2/inode.c | 1 + fs/nilfs2/namei.c | 1 + fs/ocfs2/inode.c | 1 + fs/ocfs2/namei.c | 1 + fs/qnx4/inode.c | 1 + fs/qnx6/inode.c | 1 + fs/ramfs/inode.c | 1 + fs/reiserfs/inode.c | 1 + fs/reiserfs/namei.c | 1 + fs/romfs/super.c | 1 + fs/squashfs/inode.c | 2 ++ fs/sysv/inode.c | 1 + fs/udf/inode.c | 1 + fs/udf/namei.c | 1 + fs/udf/symlink.c | 4 +--- fs/ufs/inode.c | 1 + fs/ufs/namei.c | 1 + include/linux/fs.h | 1 + mm/shmem.c | 9 +++------ 57 files changed, 81 insertions(+), 46 deletions(-)
Documentation/filesystems/porting +5 -0
@@ -504,3 +504,8 @@ in your dentry operations instead. [mandatory] __fd_install() & fd_install() can now sleep. Callers should not hold a spinlock or other resources that do not allow a schedule. +-- +[mandatory] + any symlink that might use page_follow_link_light/page_put_link() must + have inode_nohighmem(inode) called before anything might start playing with + its pagecache.
fs/affs/inode.c +1 -0
@@ -140,6 +140,7 @@ struct inode *affs_iget(struct super_block *sb, unsigned long ino)break ;case ST_SOFTLINK : inode->i_mode |=S_IFLNK ; +inode_nohighmem (inode); inode->i_op = &affs_symlink_inode_operations; inode->i_data.a_ops = &affs_symlink_aops;break ;
fs/affs/namei.c +1 -0
@@ -344,6 +344,7 @@ affs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)return -ENOSPC ; inode->i_op = &affs_symlink_inode_operations; +inode_nohighmem (inode); inode->i_data.a_ops = &affs_symlink_aops; inode->i_mode =S_IFLNK |0777 ;mode_to_prot (inode);
fs/affs/symlink.c +1 -3
@@ -14,7 +14,7 @@ static int affs_symlink_readpage(struct file *file, struct page *page) {struct buffer_head *bh;struct inode *inode = page->mapping->host; -char *link =kmap (page); +char *link =page_address (page);struct slink_front *lf;int i, j;char c;
@@ -57,12 +57,10 @@ static int affs_symlink_readpage(struct file *file, struct page *page) link[i] ='\0' ;affs_brelse (bh);SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ; fail:SetPageError (page); -kunmap (page);unlock_page (page);return -EIO ; }
fs/afs/inode.c +1 -0
@@ -56,6 +56,7 @@ static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)case AFS_FTYPE_SYMLINK : inode->i_mode =S_IFLNK | vnode->status.mode; inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode);break ;default :printk ("kAFS: AFS vnode with undefined type\n" );
fs/befs/linuxvfs.c +2 -3
@@ -397,6 +397,7 @@ static struct inode *befs_iget(struct super_block *sb, unsigned long ino) }else if (S_ISLNK (inode->i_mode)) {if (befs_ino->i_flags &BEFS_LONG_SYMLINK ) { inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &befs_symlink_aops; }else { inode->i_link = befs_ino->i_data.symlink;
@@ -469,7 +470,7 @@ static int befs_symlink_readpage(struct file *unused, struct page *page)struct befs_inode_info *befs_ino =BEFS_I (inode);befs_data_stream *data = &befs_ino->i_data.ds;befs_off_t len = data->size; -char *link =kmap (page); +char *link =page_address (page);if (len ==0 || len >PAGE_SIZE ) {befs_error (sb,"Long symlink with illegal length" );
@@ -483,12 +484,10 @@ static int befs_symlink_readpage(struct file *unused, struct page *page) } link[len -1 ] ='\0' ;SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ; fail:SetPageError (page); -kunmap (page);unlock_page (page);return -EIO ; }
fs/btrfs/inode.c +2 -0
@@ -3774,6 +3774,7 @@ cache_acl:break ;case S_IFLNK : inode->i_op = &btrfs_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &btrfs_symlink_aops;break ;default :
@@ -9705,6 +9706,7 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,btrfs_free_path (path); inode->i_op = &btrfs_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &btrfs_symlink_aops;inode_set_bytes (inode, name_len);btrfs_i_size_write (inode, name_len);
fs/coda/cnode.c +2 -0
@@ -8,6 +8,7 @@#include <linux/coda.h> #include <linux/coda_psdev.h> +#include <linux/pagemap.h> #include "coda_linux.h" static inline int coda_fideq (struct CodaFid *fid1,struct CodaFid *fid2)
@@ -35,6 +36,7 @@ static void coda_fill_inode(struct inode *inode, struct coda_vattr *attr) inode->i_fop = &coda_dir_operations; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &coda_symlink_inode_operations; +inode_nohighmem (inode); inode->i_data.a_ops = &coda_symlink_aops; inode->i_mapping = &inode->i_data; }else
fs/coda/symlink.c +1 -3
@@ -26,7 +26,7 @@ static int coda_symlink_filler(struct file *file, struct page *page)int error;struct coda_inode_info *cii;unsigned int len =PAGE_SIZE ; -char *p =kmap (page); +char *p =page_address (page); cii =ITOC (inode);
@@ -34,13 +34,11 @@ static int coda_symlink_filler(struct file *file, struct page *page)if (error) goto fail;SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ; fail:SetPageError (page); -kunmap (page);unlock_page (page);return error; }
fs/cramfs/inode.c +1 -0
@@ -100,6 +100,7 @@ static struct inode *get_cramfs_inode(struct super_block *sb,break ;case S_IFLNK : inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_data.a_ops = &cramfs_aops;break ;default :
fs/efs/inode.c +1 -0
@@ -151,6 +151,7 @@ struct inode *efs_iget(struct super_block *super, unsigned long ino)break ;case S_IFLNK : inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_data.a_ops = &efs_symlink_aops;break ;case S_IFCHR :
fs/efs/symlink.c +1 -3
@@ -13,7 +13,7 @@static int efs_symlink_readpage (struct file *file,struct page *page) { -char *link =kmap (page); +char *link =page_address (page);struct buffer_head * bh;struct inode * inode = page->mapping->host;efs_block_t size = inode->i_size;
@@ -39,12 +39,10 @@ static int efs_symlink_readpage(struct file *file, struct page *page) } link[size] ='\0' ;SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ; fail:SetPageError (page); -kunmap (page);unlock_page (page);return err; }
fs/exofs/inode.c +1 -0
@@ -1227,6 +1227,7 @@ struct inode *exofs_iget(struct super_block *sb, unsigned long ino) inode->i_link = (char *)oi->i_data; }else { inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &exofs_aops; } }else {
fs/exofs/namei.c +1 -0
@@ -111,6 +111,7 @@ static int exofs_symlink(struct inode *dir, struct dentry *dentry,if (l >sizeof (oi->i_data)) {/* slow symlink */ inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &exofs_aops;memset (oi->i_data,0 ,sizeof (oi->i_data));
fs/ext2/inode.c +1 -0
@@ -1420,6 +1420,7 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino) sizeof(ei->i_data) - 1); }else { inode->i_op = &ext2_symlink_inode_operations; +inode_nohighmem (inode);if (test_opt (inode->i_sb,NOBH )) inode->i_mapping->a_ops = &ext2_nobh_aops;else
fs/ext2/namei.c +1 -0
@@ -183,6 +183,7 @@ static int ext2_symlink (struct inode * dir, struct dentry * dentry,if (l >sizeof (EXT2_I (inode)->i_data)) {/* slow symlink */ inode->i_op = &ext2_symlink_inode_operations; +inode_nohighmem (inode);if (test_opt (inode->i_sb,NOBH )) inode->i_mapping->a_ops = &ext2_nobh_aops;else
fs/ext4/inode.c +1 -0
@@ -4283,6 +4283,7 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino) inode->i_op = &ext4_symlink_inode_operations;ext4_set_aops (inode); } +inode_nohighmem (inode); }else if (S_ISCHR (inode->i_mode) ||S_ISBLK (inode->i_mode) ||S_ISFIFO (inode->i_mode) ||S_ISSOCK (inode->i_mode)) { inode->i_op = &ext4_special_inode_operations;
fs/ext4/namei.c +1 -0
@@ -3132,6 +3132,7 @@ static int ext4_symlink(struct inode *dir,if ((disk_link.len >EXT4_N_BLOCKS *4 )) {if (!encryption_required) inode->i_op = &ext4_symlink_inode_operations; +inode_nohighmem (inode);ext4_set_aops (inode);/* * We cannot call page_symlink() with transaction started
fs/ext4/symlink.c +3 -7
@@ -45,7 +45,7 @@ static const char *ext4_encrypted_follow_link(struct dentry *dentry, void **cook cpage =read_mapping_page (inode->i_mapping,0 ,NULL );if (IS_ERR (cpage))return ERR_CAST (cpage); - caddr =kmap (cpage); + caddr =page_address (cpage); caddr[size] =0 ; }
@@ -75,16 +75,12 @@ static const char *ext4_encrypted_follow_link(struct dentry *dentry, void **cook/* Null-terminate the name */ if (res <= plen) paddr[res] ='\0' ; -if (cpage) { -kunmap (cpage); +if (cpage)page_cache_release (cpage); - }return *cookie = paddr; errout: -if (cpage) { -kunmap (cpage); +if (cpage)page_cache_release (cpage); - }kfree (paddr);return ERR_PTR (res); }
fs/f2fs/inode.c +1 -0
@@ -202,6 +202,7 @@ make_now: inode->i_op = &f2fs_encrypted_symlink_inode_operations; else inode->i_op = &f2fs_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &f2fs_dblock_aops; }else if (S_ISCHR (inode->i_mode) ||S_ISBLK (inode->i_mode) ||S_ISFIFO (inode->i_mode) ||S_ISSOCK (inode->i_mode)) {
fs/f2fs/namei.c +2 -3
@@ -351,6 +351,7 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry, inode->i_op = &f2fs_encrypted_symlink_inode_operations; else inode->i_op = &f2fs_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &f2fs_dblock_aops;f2fs_lock_op (sbi);
@@ -942,7 +943,7 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook cpage =read_mapping_page (inode->i_mapping,0 ,NULL );if (IS_ERR (cpage))return ERR_CAST (cpage); - caddr =kmap (cpage); + caddr =page_address (cpage); caddr[size] =0 ;/* Symlink is encrypted */
@@ -982,13 +983,11 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook/* Null-terminate the name */ paddr[res] ='\0' ; -kunmap (cpage);page_cache_release (cpage);return *cookie = paddr; errout:kfree (cstr.name);f2fs_fname_crypto_free_buffer (&pstr); -kunmap (cpage);page_cache_release (cpage);return ERR_PTR (res); }
fs/freevxfs/vxfs_inode.c +1 -0
@@ -326,6 +326,7 @@ vxfs_iget(struct super_block *sbp, ino_t ino) }else if (S_ISLNK (ip->i_mode)) {if (!VXFS_ISIMMED (vip)) { ip->i_op = &page_symlink_inode_operations; +inode_nohighmem (ip); ip->i_mapping->a_ops = &vxfs_aops; }else { ip->i_op = &simple_symlink_inode_operations;
fs/hfsplus/inode.c +2 -0
@@ -403,6 +403,7 @@ struct inode *hfsplus_new_inode(struct super_block *sb, umode_t mode) }else if (S_ISLNK (inode->i_mode)) { sbi->file_count++; inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &hfsplus_aops; hip->clump_blocks =1 ; }else
@@ -526,6 +527,7 @@ int hfsplus_cat_read_inode(struct inode *inode, struct hfs_find_data *fd) inode->i_mapping->a_ops = &hfsplus_aops; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &hfsplus_aops; }else { init_special_inode(inode, inode->i_mode,
fs/hpfs/inode.c +1 -0
@@ -77,6 +77,7 @@ void hpfs_read_inode(struct inode *i)kfree (ea); i->i_mode =S_IFLNK |0777 ; i->i_op = &page_symlink_inode_operations; +inode_nohighmem (i); i->i_data.a_ops = &hpfs_symlink_aops;set_nlink (i,1 ); i->i_size = ea_size;
fs/hpfs/namei.c +2 -3
@@ -332,6 +332,7 @@ static int hpfs_symlink(struct inode *dir, struct dentry *dentry, const char *sy result->i_blocks =1 ;set_nlink (result,1 ); result->i_size =strlen (symlink); +inode_nohighmem (result); result->i_op = &page_symlink_inode_operations; result->i_data.a_ops = &hpfs_symlink_aops;
@@ -500,7 +501,7 @@ out:static int hpfs_symlink_readpage (struct file *file,struct page *page) { -char *link =kmap (page); +char *link =page_address (page);struct inode *i = page->mapping->host;struct fnode *fnode;struct buffer_head *bh;
@@ -516,14 +517,12 @@ static int hpfs_symlink_readpage(struct file *file, struct page *page) goto fail;hpfs_unlock (i->i_sb);SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ; fail:hpfs_unlock (i->i_sb);SetPageError (page); -kunmap (page);unlock_page (page);return err; }
fs/hugetlbfs/inode.c +1 -0
@@ -760,6 +760,7 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb,break ;case S_IFLNK : inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode);break ; }lockdep_annotate_inode_mutex_key (inode);
fs/inode.c +6 -0
@@ -2028,3 +2028,9 @@ void inode_set_flags(struct inode *inode, unsigned int flags, new_flags) != old_flags)); }EXPORT_SYMBOL (inode_set_flags); + +void inode_nohighmem (struct inode *inode) +{ +mapping_set_gfp_mask (inode->i_mapping,GFP_USER ); +} +EXPORT_SYMBOL (inode_nohighmem);
fs/isofs/inode.c +1 -0
@@ -1417,6 +1417,7 @@ static int isofs_read_inode(struct inode *inode, int relocated) inode->i_fop = &isofs_dir_operations; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_data.a_ops = &isofs_symlink_aops; }else /* XXX - parse_rock_ridge_inode() had already set i_rdev. */
fs/isofs/rock.c +1 -3
@@ -687,7 +687,7 @@ static int rock_ridge_symlink_readpage(struct file *file, struct page *page)struct inode *inode = page->mapping->host;struct iso_inode_info *ei =ISOFS_I (inode);struct isofs_sb_info *sbi =ISOFS_SB (inode->i_sb); -char *link =kmap (page); +char *link =page_address (page);unsigned long bufsize =ISOFS_BUFFER_SIZE (inode);struct buffer_head *bh;char *rpnt = link;
@@ -774,7 +774,6 @@ repeat:brelse (bh); *rpnt ='\0' ;SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ;
@@ -791,7 +790,6 @@ fail:brelse (bh); error:SetPageError (page); -kunmap (page);unlock_page (page);return -EIO ; }
fs/jfs/inode.c +1 -0
@@ -60,6 +60,7 @@ struct inode *jfs_iget(struct super_block *sb, unsigned long ino) }else if (S_ISLNK (inode->i_mode)) {if (inode->i_size >=IDATASIZE ) { inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &jfs_aops; }else { inode->i_op = &jfs_fast_symlink_inode_operations;
fs/jfs/namei.c +1 -0
@@ -983,6 +983,7 @@ static int jfs_symlink(struct inode *dip, struct dentry *dentry,jfs_info ("jfs_symlink: allocate extent ip:0x%p" , ip); ip->i_op = &jfs_symlink_inode_operations; +inode_nohighmem (ip); ip->i_mapping->a_ops = &jfs_aops;/*
fs/logfs/dir.c +1 -0
@@ -529,6 +529,7 @@ static int logfs_symlink(struct inode *dir, struct dentry *dentry,return PTR_ERR (inode); inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &logfs_reg_aops;return __logfs_create (dir, dentry, inode, target, destlen);
fs/logfs/inode.c +1 -0
@@ -65,6 +65,7 @@ static void logfs_inode_setops(struct inode *inode)break ;case S_IFLNK : inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &logfs_reg_aops;break ;case S_IFSOCK :/* fall through */
fs/minix/inode.c +1 -0
@@ -452,6 +452,7 @@ void minix_set_inode(struct inode *inode, dev_t rdev) inode->i_mapping->a_ops = &minix_aops; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &minix_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &minix_aops; }else init_special_inode (inode, inode->i_mode, rdev);
fs/namei.c +3 -6
@@ -4527,7 +4527,8 @@ static const char *page_getlink(struct dentry * dentry, void **cookie)if (IS_ERR (page))return (char *)page; *cookie = page; - kaddr =kmap (page); +BUG_ON (mapping_gfp_mask (mapping) & __GFP_HIGHMEM); + kaddr =page_address (page);nd_terminate_link (kaddr, dentry->d_inode->i_size,PAGE_SIZE -1 );return kaddr; }
@@ -4541,7 +4542,6 @@ EXPORT_SYMBOL(page_follow_link_light);void page_put_link (struct inode *unused,void *cookie) {struct page *page = cookie; -kunmap (page);page_cache_release (page); }EXPORT_SYMBOL (page_put_link);
@@ -4565,7 +4565,6 @@ int __page_symlink(struct inode *inode, const char *symname, int len, int nofs)struct page *page;void *fsdata;int err; -char *kaddr;unsigned int flags =AOP_FLAG_UNINTERRUPTIBLE ;if (nofs) flags |=AOP_FLAG_NOFS ;
@@ -4576,9 +4575,7 @@ retry:if (err) goto fail; - kaddr =kmap_atomic (page); -memcpy (kaddr, symname, len-1 ); -kunmap_atomic (kaddr); +memcpy (page_address (page), symname, len-1 ); err =pagecache_write_end (NULL , mapping,0 , len-1 , len-1 , page, fsdata);
fs/ncpfs/inode.c +1 -0
@@ -283,6 +283,7 @@ ncp_iget(struct super_block *sb, struct ncp_entry_info *info)#if defined(CONFIG_NCPFS_EXTRAS ) || defined(CONFIG_NCPFS_NFS_NS ) } else if (S_ISLNK(inode->i_mode)) { inode->i_op = &ncp_symlink_inode_operations; +inode_nohighmem (inode); inode->i_data.a_ops = &ncp_symlink_aops;#endif }else {
fs/nfs/inode.c +3 -2
@@ -408,9 +408,10 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr, st inode->i_fop =NULL ; inode->i_flags |=S_AUTOMOUNT ; } - }else if (S_ISLNK (inode->i_mode)) + }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &nfs_symlink_inode_operations; -else +inode_nohighmem (inode); + }else init_special_inode (inode, inode->i_mode, fattr->rdev);memset (&inode->i_atime,0 ,sizeof (inode->i_atime));
fs/nfs/symlink.c +1 -1
@@ -56,7 +56,7 @@ static const char *nfs_follow_link(struct dentry *dentry, void **cookie)if (IS_ERR (page))return ERR_CAST (page); *cookie = page; -return kmap (page); +return page_address (page); }/*
fs/nilfs2/inode.c +1 -0
@@ -510,6 +510,7 @@ static int __nilfs_read_inode(struct super_block *sb, inode->i_mapping->a_ops = &nilfs_aops; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &nilfs_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &nilfs_aops; }else { inode->i_op = &nilfs_special_inode_operations;
fs/nilfs2/namei.c +1 -0
@@ -161,6 +161,7 @@ static int nilfs_symlink(struct inode *dir, struct dentry *dentry,/* slow symlink */ inode->i_op = &nilfs_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &nilfs_aops; err =page_symlink (inode, symname, l);if (err)
fs/ocfs2/inode.c +1 -0
@@ -361,6 +361,7 @@ void ocfs2_populate_inode(struct inode *inode, struct ocfs2_dinode *fe,break ;case S_IFLNK : inode->i_op = &ocfs2_symlink_inode_operations; +inode_nohighmem (inode);i_size_write (inode,le64_to_cpu (fe->i_size));break ;default :
fs/ocfs2/namei.c +1 -0
@@ -1960,6 +1960,7 @@ static int ocfs2_symlink(struct inode *dir, inode->i_rdev =0 ; newsize = l -1 ; inode->i_op = &ocfs2_symlink_inode_operations; +inode_nohighmem (inode);if (l >ocfs2_fast_symlink_chars (sb)) {u32 offset =0 ;
fs/qnx4/inode.c +1 -0
@@ -316,6 +316,7 @@ struct inode *qnx4_iget(struct super_block *sb, unsigned long ino) inode->i_fop = &qnx4_dir_operations; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &qnx4_aops;qnx4_i (inode)->mmu_private = inode->i_size; }else {
fs/qnx6/inode.c +1 -0
@@ -582,6 +582,7 @@ struct inode *qnx6_iget(struct super_block *sb, unsigned ino) inode->i_mapping->a_ops = &qnx6_aops; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &qnx6_aops; }else init_special_inode (inode, inode->i_mode,0 );
fs/ramfs/inode.c +1 -0
@@ -79,6 +79,7 @@ struct inode *ramfs_get_inode(struct super_block *sb,break ;case S_IFLNK : inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode);break ; } }
fs/reiserfs/inode.c +1 -0
@@ -1361,6 +1361,7 @@ static void init_inode(struct inode *inode, struct treepath *path) inode->i_fop = &reiserfs_dir_operations; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &reiserfs_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &reiserfs_address_space_operations; }else { inode->i_blocks =0 ;
fs/reiserfs/namei.c +1 -0
@@ -1170,6 +1170,7 @@ static int reiserfs_symlink(struct inode *parent_dir,reiserfs_update_inode_transaction (parent_dir); inode->i_op = &reiserfs_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &reiserfs_address_space_operations; retval = reiserfs_add_entry(&th, parent_dir, dentry->d_name.name,
fs/romfs/super.c +1 -0
@@ -360,6 +360,7 @@ static struct inode *romfs_iget(struct super_block *sb, unsigned long pos)break ;case ROMFH_SYM : i->i_op = &page_symlink_inode_operations; +inode_nohighmem (i); i->i_data.a_ops = &romfs_aops; mode |=S_IRWXUGO ;break ;
fs/squashfs/inode.c +2 -0
@@ -41,6 +41,7 @@#include <linux/fs.h> #include <linux/vfs.h> #include <linux/xattr.h> +#include <linux/pagemap.h> #include "squashfs_fs.h" #include "squashfs_fs_sb.h"
@@ -291,6 +292,7 @@ int squashfs_read_inode(struct inode *inode, long long ino)set_nlink (inode,le32_to_cpu (sqsh_ino->nlink)); inode->i_size =le32_to_cpu (sqsh_ino->symlink_size); inode->i_op = &squashfs_symlink_inode_ops; +inode_nohighmem (inode); inode->i_data.a_ops = &squashfs_symlink_aops; inode->i_mode |=S_IFLNK ;squashfs_i (inode)->start = block;
fs/sysv/inode.c +1 -0
@@ -163,6 +163,7 @@ void sysv_set_inode(struct inode *inode, dev_t rdev) inode->i_mapping->a_ops = &sysv_aops; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &sysv_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &sysv_aops; }else init_special_inode (inode, inode->i_mode, rdev);
fs/udf/inode.c +1 -0
@@ -1541,6 +1541,7 @@ reread:case ICBTAG_FILE_TYPE_SYMLINK : inode->i_data.a_ops = &udf_symlink_aops; inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mode =S_IFLNK |S_IRWXUGO ;break ;case ICBTAG_FILE_TYPE_MAIN :
fs/udf/namei.c +1 -0
@@ -922,6 +922,7 @@ static int udf_symlink(struct inode *dir, struct dentry *dentry, inode->i_data.a_ops = &udf_symlink_aops; inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode);if (iinfo->i_alloc_type !=ICBTAG_FLAG_AD_IN_ICB ) {struct kernel_lb_addr eloc;
fs/udf/symlink.c +1 -3
@@ -107,7 +107,7 @@ static int udf_symlink_filler(struct file *file, struct page *page)struct buffer_head *bh =NULL ;unsigned char *symlink;int err; -unsigned char *p =kmap (page); +unsigned char *p =page_address (page);struct udf_inode_info *iinfo;uint32_t pos;
@@ -141,7 +141,6 @@ static int udf_symlink_filler(struct file *file, struct page *page)up_read (&iinfo->i_data_sem);SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ;
@@ -149,7 +148,6 @@ out_unlock_inode:up_read (&iinfo->i_data_sem);SetPageError (page); out_unmap: -kunmap (page);unlock_page (page);return err; }
fs/ufs/inode.c +1 -0
@@ -533,6 +533,7 @@ static void ufs_set_inode_ops(struct inode *inode) }else { inode->i_mapping->a_ops = &ufs_aops; inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); } }else init_special_inode(inode, inode->i_mode,
fs/ufs/namei.c +1 -0
@@ -124,6 +124,7 @@ static int ufs_symlink (struct inode * dir, struct dentry * dentry,if (l >UFS_SB (sb)->s_uspi->s_maxsymlinklen) {/* slow symlink */ inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &ufs_aops; err =page_symlink (inode, symname, l);if (err)
include/linux/fs.h +1 -0
@@ -3025,5 +3025,6 @@ static inline bool dir_relax(struct inode *inode) }extern bool path_noexec (const struct path *path); +extern void inode_nohighmem (struct inode *inode);#endif /* _LINUX_FS_H */
mm/shmem.c +3 -6
@@ -2444,7 +2444,6 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *sint len;struct inode *inode;struct page *page; -char *kaddr;struct shmem_inode_info *info; len =strlen (symname) +1 ;
@@ -2483,9 +2482,8 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s } inode->i_mapping->a_ops = &shmem_aops; inode->i_op = &shmem_symlink_inode_operations; - kaddr =kmap_atomic (page); -memcpy (kaddr, symname, len); -kunmap_atomic (kaddr); +inode_nohighmem (inode); +memcpy (page_address (page), symname, len);SetPageUptodate (page);set_page_dirty (page);unlock_page (page);
@@ -2506,13 +2504,12 @@ static const char *shmem_follow_link(struct dentry *dentry, void **cookie)return ERR_PTR (error);unlock_page (page); *cookie = page; -return kmap (page); +return page_address (page); }static void shmem_put_link (struct inode *unused,void *cookie) {struct page *page = cookie; -kunmap (page);mark_page_accessed (page);page_cache_release (page); }
Signature · 1 line
2.1.4
Re: [PATCH v2 06/11] don't put symlink bodies in pagecache into highmem
Quoted 9 lines · Al Viro
From: Al Viro <[email protected]>
kmap()inpage_follow_link_light()needed to go - allowing to hold an arbitrary number of kmaps for long is a great way to deadlocking the system.new helper (
inode_nohighmem(inode)) needs to be used for pagecache symlinks inodes; done for all in-tree cases.page_follow_link_light()instrumented to yell about anything missed.
Hi, starting with with this change, I get this oops when installing packages into a rootfs in NFS:
[ 144.455632] Unable to handle kernel NULL pointer dereference at
virtual address 00000000
[ 144.463726] pgd = ee760000
[ 144.466441] [00000000] *pgd=7b83f831
[ 144.470036] Internal error: Oops: 17 [#1] SMP ARM
[ 144.474732] Modules linked in:
[ 144.477798] CPU: 2 PID: 1 Comm: systemd Not tainted
4.4.0-rc4-00006-g21fc61c73c39-dirty #3521
[ 144.486307] Hardware name: Rockchip (Device Tree)
[ 144.491004] task: ee078000 ti: ee062000 task.ti: ee062000
[ 144.496399] PC is at strlen+0x0/0x2c
[ 144.499972] LR is at readlink_copy+0x24/0x94
[ 144.504236] pc : [<c049019c>] lr : [<c031ae40>] psr: 00000013
[ 144.504236] sp : ee063f38 ip : 00000000 fp : ec8a66b0
[ 144.515694] r10: 001acf88 r9 : 00000063 r8 : ee063f74
[ 144.520909] r7 : 001acef8 r6 : 001acf88 r5 : 00000000 r4 : 00000063
[ 144.527424] r3 : c0ee8e94 r2 : 00000000 r1 : 00000063 r0 : 00000000
[ 144.533939] Flags: nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
[ 144.541060] Control: 10c5387d Table: 2e76006a DAC: 00000051
[ 144.546794] Process systemd (pid: 1, stack limit = 0xee062220)
[ 144.552614] Stack: (0xee063f38 to 0xee064000)
[ 144.556962] 3f20:
001acf88 ec8a66b0
[ 144.565126] 3f40: 00000063 001acef8 ee063f74 c031aedc 001acf88
eff69f20 ffffffea 00004000
[ 144.573290] 3f60: ffffff9c c0315e94 00000000 00000000 00000025
00000000 ee5f89d0 ec8367f8
[ 144.581453] 3f80: 56978623 001acf88 00000064 00000063 0000014c
c0210d44 ee062000 00000000
[ 144.589616] 3fa0: 001acef8 c0210b80 001acf88 00000064 ffffff9c
001acef8 001acf88 00000063
[ 144.597780] 3fc0: 001acf88 00000064 00000063 0000014c be8930b8
001bcc94 0018695b 001acef8
[ 144.605943] 3fe0: 0000014c be893094 b6f3bf7b b6ec98e6 20000030
ffffff9c ffffffff ffeffffe
[ 144.614109] [<c049019c>] (strlen) from [<c031ae40>] (readlink_copy+0x24/0x94)
[ 144.621234] [<c031ae40>] (readlink_copy) from [<c031aedc>]
(generic_readlink+0x2c/0x78)
[ 144.629224] [<c031aedc>] (generic_readlink) from [<c0315e94>]
(SyS_readlinkat+0x98/0xe0)
[ 144.637301] [<c0315e94>] (SyS_readlinkat) from [<c0210b80>]
(ret_fast_syscall+0x0/0x3c)
[ 144.645290] Code: e7d23003 e3130020 1afffffb e12fff1e (e5d02000)
[ 144.651388] ---[ end trace 299126b4c29ad1e5 ]---
[ 144.658936] Kernel panic - not syncing: Attempted to kill init!
exitcode=0x0000000b
[ 144.658936]
[ 144.668056] CPU1: stopping
[ 144.670759] CPU: 1 PID: 0 Comm: swapper/1 Tainted: G D
4.4.0-rc4-00006-g21fc61c73c39-dirty #3521
[ 144.680651] Hardware name: Rockchip (Device Tree)
[ 144.685355] [<c02191a0>] (unwind_backtrace) from [<c0214898>]
(show_stack+0x10/0x14)
[ 144.693085] [<c0214898>] (show_stack) from [<c0489ac4>]
(dump_stack+0x84/0x94)
[ 144.700295] [<c0489ac4>] (dump_stack) from [<c0217950>]
(handle_IPI+0x188/0x1a8)
[ 144.707678] [<c0217950>] (handle_IPI) from [<c020a740>]
(gic_handle_irq+0x90/0x94)
[ 144.715233] [<c020a740>] (gic_handle_irq) from [<c02153d4>]
(__irq_svc+0x54/0x70)
[ 144.722698] Exception stack(0xee0a7f80 to 0xee0a7fc8)
[ 144.727739] 7f80: 00000001 00000000 00000000 c0223ae0 ee0a6000
c0ef04a4 00000000 00000000
[ 144.735900] 7fa0: ee0a7fd8 c0ef0504 c09f7624 c0ef050c 2e0ca000
ee0a7fd0 c0211668 c021166c
[ 144.744060] 7fc0: 60070013 ffffffff
[ 144.747543] [<c02153d4>] (__irq_svc) from [<c021166c>]
(arch_cpu_idle+0x38/0x3c)
[ 144.754926] [<c021166c>] (arch_cpu_idle) from [<c028158c>]
(cpu_startup_entry+0x1ec/0x248)
[ 144.763175] [<c028158c>] (cpu_startup_entry) from [<0020ab4c>] (0x20ab4c)
[ 144.769948] CPU0: stopping
[ 144.772650] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G D
4.4.0-rc4-00006-g21fc61c73c39-dirty #3521
[ 144.782543] Hardware name: Rockchip (Device Tree)
[ 144.787241] [<c02191a0>] (unwind_backtrace) from [<c0214898>]
(show_stack+0x10/0x14)
[ 144.794970] [<c0214898>] (show_stack) from [<c0489ac4>]
(dump_stack+0x84/0x94)
[ 144.802179] [<c0489ac4>] (dump_stack) from [<c0217950>]
(handle_IPI+0x188/0x1a8)
[ 144.809560] [<c0217950>] (handle_IPI) from [<c020a740>]
(gic_handle_irq+0x90/0x94)
[ 144.817114] [<c020a740>] (gic_handle_irq) from [<c02153d4>]
(__irq_svc+0x54/0x70)
[ 144.824579] Exception stack(0xc0eeff48 to 0xc0eeff90)
[ 144.829620] ff40: 00000001 00000000 00000000
c0223ae0 c0eee000 c0ef04a4
[ 144.837782] ff60: 00000000 00000000 c0eeffa0 c0ef0504 c09f7624
c0ef050c 60000013 c0eeff98
[ 144.845942] ff80: c0211668 c021166c 60000013 ffffffff
[ 144.850983] [<c02153d4>] (__irq_svc) from [<c021166c>]
(arch_cpu_idle+0x38/0x3c)
[ 144.858365] [<c021166c>] (arch_cpu_idle) from [<c028158c>]
(cpu_startup_entry+0x1ec/0x248)
[ 144.866614] [<c028158c>] (cpu_startup_entry) from [<c0de6c88>]
(start_kernel+0x3a8/0x3b4)
[ 144.874775] CPU3: stopping
[ 144.877477] CPU: 3 PID: 8117 Comm: apt-get Tainted: G D
4.4.0-rc4-00006-g21fc61c73c39-dirty #3521
[ 144.887455] Hardware name: Rockchip (Device Tree)
[ 144.892154] [<c02191a0>] (unwind_backtrace) from [<c0214898>]
(show_stack+0x10/0x14)
[ 144.899885] [<c0214898>] (show_stack) from [<c0489ac4>]
(dump_stack+0x84/0x94)
[ 144.907094] [<c0489ac4>] (dump_stack) from [<c0217950>]
(handle_IPI+0x188/0x1a8)
[ 144.914475] [<c0217950>] (handle_IPI) from [<c020a740>]
(gic_handle_irq+0x90/0x94)
[ 144.922028] [<c020a740>] (gic_handle_irq) from [<c02153d4>]
(__irq_svc+0x54/0x70)
[ 144.929494] Exception stack(0xed57da88 to 0xed57dad0)
[ 144.934535] da80: c1020dc4 a0000013 c1020dc4
000079a8 00000000 ee273dd0
[ 144.942696] daa0: f0bbd000 ee5d2300 00000000 00000000 0000000c
00000000 00000000 ed57dad8
[ 144.950856] dac0: c059f2ec c09ef788 60000013 ffffffff
[ 144.955899] [<c02153d4>] (__irq_svc) from [<c09ef788>]
(_raw_spin_unlock_irqrestore+0x1c/0x20)
[ 144.964496] [<c09ef788>] (_raw_spin_unlock_irqrestore) from
[<c059f2ec>] (uart_chars_in_buffer+0x2c/0x34)
[ 144.974046] [<c059f2ec>] (uart_chars_in_buffer) from [<c0588520>]
(n_tty_poll+0x180/0x19c)
[ 144.982294] [<c0588520>] (n_tty_poll) from [<c0585418>] (tty_poll+0x6c/0x80)
[ 144.989329] [<c0585418>] (tty_poll) from [<c0322f08>] (do_select+0x2dc/0x618)
[ 144.996451] [<c0322f08>] (do_select) from [<c0323378>]
(core_sys_select+0x134/0x3f4)
[ 145.004179] [<c0323378>] (core_sys_select) from [<c0323940>]
(SyS_pselect6+0x1d8/0x31c)
[ 145.012168] [<c0323940>] (SyS_pselect6) from [<c0210b80>]
(ret_fast_syscall+0x0/0x3c)
[ 145.019985] ---[ end Kernel panic - not syncing: Attempted to killinit! exitcode=0x0000000b
Without it, the symlink is read correctly and there's no oops.
Regards,
Tomeu
Quoted 1,015 lines
Signed-off-by Al Viro <[email protected]>--- Documentation/filesystems/porting | 5 +++++ fs/affs/inode.c | 1 + fs/affs/namei.c | 1 + fs/affs/symlink.c | 4 +--- fs/afs/inode.c | 1 + fs/befs/linuxvfs.c | 5 ++--- fs/btrfs/inode.c | 2 ++ fs/coda/cnode.c | 2 ++ fs/coda/symlink.c | 4 +--- fs/cramfs/inode.c | 1 + fs/efs/inode.c | 1 + fs/efs/symlink.c | 4 +--- fs/exofs/inode.c | 1 + fs/exofs/namei.c | 1 + fs/ext2/inode.c | 1 + fs/ext2/namei.c | 1 + fs/ext4/inode.c | 1 + fs/ext4/namei.c | 1 + fs/ext4/symlink.c | 10 +++------- fs/f2fs/inode.c | 1 + fs/f2fs/namei.c | 5 ++--- fs/freevxfs/vxfs_inode.c | 1 + fs/hfsplus/inode.c | 2 ++ fs/hpfs/inode.c | 1 + fs/hpfs/namei.c | 5 ++--- fs/hugetlbfs/inode.c | 1 + fs/inode.c | 6 ++++++ fs/isofs/inode.c | 1 + fs/isofs/rock.c | 4 +--- fs/jfs/inode.c | 1 + fs/jfs/namei.c | 1 + fs/logfs/dir.c | 1 + fs/logfs/inode.c | 1 + fs/minix/inode.c | 1 + fs/namei.c | 9 +++------ fs/ncpfs/inode.c | 1 + fs/nfs/inode.c | 5 +++-- fs/nfs/symlink.c | 2 +- fs/nilfs2/inode.c | 1 + fs/nilfs2/namei.c | 1 + fs/ocfs2/inode.c | 1 + fs/ocfs2/namei.c | 1 + fs/qnx4/inode.c | 1 + fs/qnx6/inode.c | 1 + fs/ramfs/inode.c | 1 + fs/reiserfs/inode.c | 1 + fs/reiserfs/namei.c | 1 + fs/romfs/super.c | 1 + fs/squashfs/inode.c | 2 ++ fs/sysv/inode.c | 1 + fs/udf/inode.c | 1 + fs/udf/namei.c | 1 + fs/udf/symlink.c | 4 +--- fs/ufs/inode.c | 1 + fs/ufs/namei.c | 1 + include/linux/fs.h | 1 + mm/shmem.c | 9 +++------ 57 files changed, 81 insertions(+), 46 deletions(-)Documentation/filesystems/porting +5
-0@@ -504,3 +504,8 @@ in your dentry operations instead. [mandatory] __fd_install() & fd_install() can now sleep. Callers should not hold a spinlock or other resources that do not allow a schedule. +-- +[mandatory] + any symlink that might use page_follow_link_light/page_put_link() must + have inode_nohighmem(inode) called before anything might start playing with + its pagecache.fs/affs/inode.c +1
-0@@ -140,6 +140,7 @@ struct inode *affs_iget(struct super_block *sb, unsigned long ino)break ;case ST_SOFTLINK : inode->i_mode |=S_IFLNK ; +inode_nohighmem (inode); inode->i_op = &affs_symlink_inode_operations; inode->i_data.a_ops = &affs_symlink_aops;break ;fs/affs/namei.c +1
-0@@ -344,6 +344,7 @@ affs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)return -ENOSPC ; inode->i_op = &affs_symlink_inode_operations; +inode_nohighmem (inode); inode->i_data.a_ops = &affs_symlink_aops; inode->i_mode =S_IFLNK |0777 ;mode_to_prot (inode);fs/affs/symlink.c +1
-3@@ -14,7 +14,7 @@ static int affs_symlink_readpage(struct file *file, struct page *page) {struct buffer_head *bh;struct inode *inode = page->mapping->host; -char *link =kmap (page); +char *link =page_address (page);struct slink_front *lf;int i, j;char c;@@ -57,12 +57,10 @@ static int affs_symlink_readpage(struct file *file, struct page *page) link[i] ='\0' ;affs_brelse (bh);SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ; fail:SetPageError (page); -kunmap (page);unlock_page (page);return -EIO ; }fs/afs/inode.c +1
-0@@ -56,6 +56,7 @@ static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)case AFS_FTYPE_SYMLINK : inode->i_mode =S_IFLNK | vnode->status.mode; inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode);break ;default :printk ("kAFS: AFS vnode with undefined type\n" );fs/befs/linuxvfs.c +2
-3@@ -397,6 +397,7 @@ static struct inode *befs_iget(struct super_block *sb, unsigned long ino) }else if (S_ISLNK (inode->i_mode)) {if (befs_ino->i_flags &BEFS_LONG_SYMLINK ) { inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &befs_symlink_aops; }else { inode->i_link = befs_ino->i_data.symlink;@@ -469,7 +470,7 @@ static int befs_symlink_readpage(struct file *unused, struct page *page)struct befs_inode_info *befs_ino =BEFS_I (inode);befs_data_stream *data = &befs_ino->i_data.ds;befs_off_t len = data->size; -char *link =kmap (page); +char *link =page_address (page);if (len ==0 || len >PAGE_SIZE ) {befs_error (sb,"Long symlink with illegal length" );@@ -483,12 +484,10 @@ static int befs_symlink_readpage(struct file *unused, struct page *page) } link[len -1 ] ='\0' ;SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ; fail:SetPageError (page); -kunmap (page);unlock_page (page);return -EIO ; }fs/btrfs/inode.c +2
-0@@ -3774,6 +3774,7 @@ cache_acl:break ;case S_IFLNK : inode->i_op = &btrfs_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &btrfs_symlink_aops;break ;default :@@ -9705,6 +9706,7 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,btrfs_free_path (path); inode->i_op = &btrfs_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &btrfs_symlink_aops;inode_set_bytes (inode, name_len);btrfs_i_size_write (inode, name_len);fs/coda/cnode.c +2
-0@@ -8,6 +8,7 @@#include <linux/coda.h> #include <linux/coda_psdev.h> +#include <linux/pagemap.h> #include "coda_linux.h" static inline int coda_fideq (struct CodaFid *fid1,struct CodaFid *fid2)@@ -35,6 +36,7 @@ static void coda_fill_inode(struct inode *inode, struct coda_vattr *attr) inode->i_fop = &coda_dir_operations; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &coda_symlink_inode_operations; +inode_nohighmem (inode); inode->i_data.a_ops = &coda_symlink_aops; inode->i_mapping = &inode->i_data; }else fs/coda/symlink.c +1
-3@@ -26,7 +26,7 @@ static int coda_symlink_filler(struct file *file, struct page *page)int error;struct coda_inode_info *cii;unsigned int len =PAGE_SIZE ; -char *p =kmap (page); +char *p =page_address (page); cii =ITOC (inode);@@ -34,13 +34,11 @@ static int coda_symlink_filler(struct file *file, struct page *page)if (error) goto fail;SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ; fail:SetPageError (page); -kunmap (page);unlock_page (page);return error; }fs/cramfs/inode.c +1
-0@@ -100,6 +100,7 @@ static struct inode *get_cramfs_inode(struct super_block *sb,break ;case S_IFLNK : inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_data.a_ops = &cramfs_aops;break ;default :fs/efs/inode.c +1
-0@@ -151,6 +151,7 @@ struct inode *efs_iget(struct super_block *super, unsigned long ino)break ;case S_IFLNK : inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_data.a_ops = &efs_symlink_aops;break ;case S_IFCHR :fs/efs/symlink.c +1
-3@@ -13,7 +13,7 @@static int efs_symlink_readpage (struct file *file,struct page *page) { -char *link =kmap (page); +char *link =page_address (page);struct buffer_head * bh;struct inode * inode = page->mapping->host;efs_block_t size = inode->i_size;@@ -39,12 +39,10 @@ static int efs_symlink_readpage(struct file *file, struct page *page) } link[size] ='\0' ;SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ; fail:SetPageError (page); -kunmap (page);unlock_page (page);return err; }fs/exofs/inode.c +1
-0@@ -1227,6 +1227,7 @@ struct inode *exofs_iget(struct super_block *sb, unsigned long ino) inode->i_link = (char *)oi->i_data; }else { inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &exofs_aops; } }else {fs/exofs/namei.c +1
-0@@ -111,6 +111,7 @@ static int exofs_symlink(struct inode *dir, struct dentry *dentry,if (l >sizeof (oi->i_data)) {/* slow symlink */ inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &exofs_aops;memset (oi->i_data,0 ,sizeof (oi->i_data));fs/ext2/inode.c +1
-0@@ -1420,6 +1420,7 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino) sizeof(ei->i_data) - 1); }else { inode->i_op = &ext2_symlink_inode_operations; +inode_nohighmem (inode);if (test_opt (inode->i_sb,NOBH )) inode->i_mapping->a_ops = &ext2_nobh_aops;else fs/ext2/namei.c +1
-0@@ -183,6 +183,7 @@ static int ext2_symlink (struct inode * dir, struct dentry * dentry,if (l >sizeof (EXT2_I (inode)->i_data)) {/* slow symlink */ inode->i_op = &ext2_symlink_inode_operations; +inode_nohighmem (inode);if (test_opt (inode->i_sb,NOBH )) inode->i_mapping->a_ops = &ext2_nobh_aops;else fs/ext4/inode.c +1
-0@@ -4283,6 +4283,7 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino) inode->i_op = &ext4_symlink_inode_operations;ext4_set_aops (inode); } +inode_nohighmem (inode); }else if (S_ISCHR (inode->i_mode) ||S_ISBLK (inode->i_mode) ||S_ISFIFO (inode->i_mode) ||S_ISSOCK (inode->i_mode)) { inode->i_op = &ext4_special_inode_operations;fs/ext4/namei.c +1
-0@@ -3132,6 +3132,7 @@ static int ext4_symlink(struct inode *dir,if ((disk_link.len >EXT4_N_BLOCKS *4 )) {if (!encryption_required) inode->i_op = &ext4_symlink_inode_operations; +inode_nohighmem (inode);ext4_set_aops (inode);/* * We cannot call page_symlink() with transaction started fs/ext4/symlink.c +3
-7@@ -45,7 +45,7 @@ static const char *ext4_encrypted_follow_link(struct dentry *dentry, void **cook cpage =read_mapping_page (inode->i_mapping,0 ,NULL );if (IS_ERR (cpage))return ERR_CAST (cpage); - caddr =kmap (cpage); + caddr =page_address (cpage); caddr[size] =0 ; }@@ -75,16 +75,12 @@ static const char *ext4_encrypted_follow_link(struct dentry *dentry, void **cook/* Null-terminate the name */ if (res <= plen) paddr[res] ='\0' ; -if (cpage) { -kunmap (cpage); +if (cpage)page_cache_release (cpage); - }return *cookie = paddr; errout: -if (cpage) { -kunmap (cpage); +if (cpage)page_cache_release (cpage); - }kfree (paddr);return ERR_PTR (res); }fs/f2fs/inode.c +1
-0@@ -202,6 +202,7 @@ make_now: inode->i_op = &f2fs_encrypted_symlink_inode_operations; else inode->i_op = &f2fs_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &f2fs_dblock_aops; }else if (S_ISCHR (inode->i_mode) ||S_ISBLK (inode->i_mode) ||S_ISFIFO (inode->i_mode) ||S_ISSOCK (inode->i_mode)) {fs/f2fs/namei.c +2
-3@@ -351,6 +351,7 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry, inode->i_op = &f2fs_encrypted_symlink_inode_operations; else inode->i_op = &f2fs_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &f2fs_dblock_aops;f2fs_lock_op (sbi);@@ -942,7 +943,7 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook cpage =read_mapping_page (inode->i_mapping,0 ,NULL );if (IS_ERR (cpage))return ERR_CAST (cpage); - caddr =kmap (cpage); + caddr =page_address (cpage); caddr[size] =0 ;/* Symlink is encrypted */ @@ -982,13 +983,11 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook/* Null-terminate the name */ paddr[res] ='\0' ; -kunmap (cpage);page_cache_release (cpage);return *cookie = paddr; errout:kfree (cstr.name);f2fs_fname_crypto_free_buffer (&pstr); -kunmap (cpage);page_cache_release (cpage);return ERR_PTR (res); }fs/freevxfs/vxfs_inode.c +1
-0@@ -326,6 +326,7 @@ vxfs_iget(struct super_block *sbp, ino_t ino) }else if (S_ISLNK (ip->i_mode)) {if (!VXFS_ISIMMED (vip)) { ip->i_op = &page_symlink_inode_operations; +inode_nohighmem (ip); ip->i_mapping->a_ops = &vxfs_aops; }else { ip->i_op = &simple_symlink_inode_operations;fs/hfsplus/inode.c +2
-0@@ -403,6 +403,7 @@ struct inode *hfsplus_new_inode(struct super_block *sb, umode_t mode) }else if (S_ISLNK (inode->i_mode)) { sbi->file_count++; inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &hfsplus_aops; hip->clump_blocks =1 ; }else @@ -526,6 +527,7 @@ int hfsplus_cat_read_inode(struct inode *inode, struct hfs_find_data *fd) inode->i_mapping->a_ops = &hfsplus_aops; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &hfsplus_aops; }else { init_special_inode(inode, inode->i_mode,fs/hpfs/inode.c +1
-0@@ -77,6 +77,7 @@ void hpfs_read_inode(struct inode *i)kfree (ea); i->i_mode =S_IFLNK |0777 ; i->i_op = &page_symlink_inode_operations; +inode_nohighmem (i); i->i_data.a_ops = &hpfs_symlink_aops;set_nlink (i,1 ); i->i_size = ea_size;fs/hpfs/namei.c +2
-3@@ -332,6 +332,7 @@ static int hpfs_symlink(struct inode *dir, struct dentry *dentry, const char *sy result->i_blocks =1 ;set_nlink (result,1 ); result->i_size =strlen (symlink); +inode_nohighmem (result); result->i_op = &page_symlink_inode_operations; result->i_data.a_ops = &hpfs_symlink_aops;@@ -500,7 +501,7 @@ out:static int hpfs_symlink_readpage (struct file *file,struct page *page) { -char *link =kmap (page); +char *link =page_address (page);struct inode *i = page->mapping->host;struct fnode *fnode;struct buffer_head *bh;@@ -516,14 +517,12 @@ static int hpfs_symlink_readpage(struct file *file, struct page *page) goto fail;hpfs_unlock (i->i_sb);SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ; fail:hpfs_unlock (i->i_sb);SetPageError (page); -kunmap (page);unlock_page (page);return err; }fs/hugetlbfs/inode.c +1
-0@@ -760,6 +760,7 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb,break ;case S_IFLNK : inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode);break ; }lockdep_annotate_inode_mutex_key (inode);fs/inode.c +6
-0@@ -2028,3 +2028,9 @@ void inode_set_flags(struct inode *inode, unsigned int flags, new_flags) != old_flags)); }EXPORT_SYMBOL (inode_set_flags); + +void inode_nohighmem (struct inode *inode) +{ +mapping_set_gfp_mask (inode->i_mapping,GFP_USER ); +} +EXPORT_SYMBOL (inode_nohighmem);fs/isofs/inode.c +1
-0@@ -1417,6 +1417,7 @@ static int isofs_read_inode(struct inode *inode, int relocated) inode->i_fop = &isofs_dir_operations; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_data.a_ops = &isofs_symlink_aops; }else /* XXX - parse_rock_ridge_inode() had already set i_rdev. */ fs/isofs/rock.c +1
-3@@ -687,7 +687,7 @@ static int rock_ridge_symlink_readpage(struct file *file, struct page *page)struct inode *inode = page->mapping->host;struct iso_inode_info *ei =ISOFS_I (inode);struct isofs_sb_info *sbi =ISOFS_SB (inode->i_sb); -char *link =kmap (page); +char *link =page_address (page);unsigned long bufsize =ISOFS_BUFFER_SIZE (inode);struct buffer_head *bh;char *rpnt = link;@@ -774,7 +774,6 @@ repeat:brelse (bh); *rpnt ='\0' ;SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ;@@ -791,7 +790,6 @@ fail:brelse (bh); error:SetPageError (page); -kunmap (page);unlock_page (page);return -EIO ; }fs/jfs/inode.c +1
-0@@ -60,6 +60,7 @@ struct inode *jfs_iget(struct super_block *sb, unsigned long ino) }else if (S_ISLNK (inode->i_mode)) {if (inode->i_size >=IDATASIZE ) { inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &jfs_aops; }else { inode->i_op = &jfs_fast_symlink_inode_operations;fs/jfs/namei.c +1
-0@@ -983,6 +983,7 @@ static int jfs_symlink(struct inode *dip, struct dentry *dentry,jfs_info ("jfs_symlink: allocate extent ip:0x%p" , ip); ip->i_op = &jfs_symlink_inode_operations; +inode_nohighmem (ip); ip->i_mapping->a_ops = &jfs_aops;/* fs/logfs/dir.c +1
-0@@ -529,6 +529,7 @@ static int logfs_symlink(struct inode *dir, struct dentry *dentry,return PTR_ERR (inode); inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &logfs_reg_aops;return __logfs_create (dir, dentry, inode, target, destlen);fs/logfs/inode.c +1
-0@@ -65,6 +65,7 @@ static void logfs_inode_setops(struct inode *inode)break ;case S_IFLNK : inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &logfs_reg_aops;break ;case S_IFSOCK :/* fall through */ fs/minix/inode.c +1
-0@@ -452,6 +452,7 @@ void minix_set_inode(struct inode *inode, dev_t rdev) inode->i_mapping->a_ops = &minix_aops; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &minix_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &minix_aops; }else init_special_inode (inode, inode->i_mode, rdev);fs/namei.c +3
-6@@ -4527,7 +4527,8 @@ static const char *page_getlink(struct dentry * dentry, void **cookie)if (IS_ERR (page))return (char *)page; *cookie = page; - kaddr =kmap (page); +BUG_ON (mapping_gfp_mask (mapping) & __GFP_HIGHMEM); + kaddr =page_address (page);nd_terminate_link (kaddr, dentry->d_inode->i_size,PAGE_SIZE -1 );return kaddr; }@@ -4541,7 +4542,6 @@ EXPORT_SYMBOL(page_follow_link_light);void page_put_link (struct inode *unused,void *cookie) {struct page *page = cookie; -kunmap (page);page_cache_release (page); }EXPORT_SYMBOL (page_put_link);@@ -4565,7 +4565,6 @@ int __page_symlink(struct inode *inode, const char *symname, int len, int nofs)struct page *page;void *fsdata;int err; -char *kaddr;unsigned int flags =AOP_FLAG_UNINTERRUPTIBLE ;if (nofs) flags |=AOP_FLAG_NOFS ;@@ -4576,9 +4575,7 @@ retry:if (err) goto fail; - kaddr =kmap_atomic (page); -memcpy (kaddr, symname, len-1 ); -kunmap_atomic (kaddr); +memcpy (page_address (page), symname, len-1 ); err =pagecache_write_end (NULL , mapping,0 , len-1 , len-1 , page, fsdata);fs/ncpfs/inode.c +1
-0@@ -283,6 +283,7 @@ ncp_iget(struct super_block *sb, struct ncp_entry_info *info)#if defined(CONFIG_NCPFS_EXTRAS ) || defined(CONFIG_NCPFS_NFS_NS ) } else if (S_ISLNK(inode->i_mode)) { inode->i_op = &ncp_symlink_inode_operations; +inode_nohighmem (inode); inode->i_data.a_ops = &ncp_symlink_aops;#endif }else {fs/nfs/inode.c +3
-2@@ -408,9 +408,10 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr, st inode->i_fop =NULL ; inode->i_flags |=S_AUTOMOUNT ; } - }else if (S_ISLNK (inode->i_mode)) + }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &nfs_symlink_inode_operations; -else +inode_nohighmem (inode); + }else init_special_inode (inode, inode->i_mode, fattr->rdev);memset (&inode->i_atime,0 ,sizeof (inode->i_atime));fs/nfs/symlink.c +1
-1@@ -56,7 +56,7 @@ static const char *nfs_follow_link(struct dentry *dentry, void **cookie)if (IS_ERR (page))return ERR_CAST (page); *cookie = page; -return kmap (page); +return page_address (page); }/* fs/nilfs2/inode.c +1
-0@@ -510,6 +510,7 @@ static int __nilfs_read_inode(struct super_block *sb, inode->i_mapping->a_ops = &nilfs_aops; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &nilfs_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &nilfs_aops; }else { inode->i_op = &nilfs_special_inode_operations;fs/nilfs2/namei.c +1
-0@@ -161,6 +161,7 @@ static int nilfs_symlink(struct inode *dir, struct dentry *dentry,/* slow symlink */ inode->i_op = &nilfs_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &nilfs_aops; err =page_symlink (inode, symname, l);if (err)fs/ocfs2/inode.c +1
-0@@ -361,6 +361,7 @@ void ocfs2_populate_inode(struct inode *inode, struct ocfs2_dinode *fe,break ;case S_IFLNK : inode->i_op = &ocfs2_symlink_inode_operations; +inode_nohighmem (inode);i_size_write (inode,le64_to_cpu (fe->i_size));break ;default :fs/ocfs2/namei.c +1
-0@@ -1960,6 +1960,7 @@ static int ocfs2_symlink(struct inode *dir, inode->i_rdev =0 ; newsize = l -1 ; inode->i_op = &ocfs2_symlink_inode_operations; +inode_nohighmem (inode);if (l >ocfs2_fast_symlink_chars (sb)) {u32 offset =0 ;fs/qnx4/inode.c +1
-0@@ -316,6 +316,7 @@ struct inode *qnx4_iget(struct super_block *sb, unsigned long ino) inode->i_fop = &qnx4_dir_operations; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &qnx4_aops;qnx4_i (inode)->mmu_private = inode->i_size; }else {fs/qnx6/inode.c +1
-0@@ -582,6 +582,7 @@ struct inode *qnx6_iget(struct super_block *sb, unsigned ino) inode->i_mapping->a_ops = &qnx6_aops; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &qnx6_aops; }else init_special_inode (inode, inode->i_mode,0 );fs/ramfs/inode.c +1
-0@@ -79,6 +79,7 @@ struct inode *ramfs_get_inode(struct super_block *sb,break ;case S_IFLNK : inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode);break ; } }fs/reiserfs/inode.c +1
-0@@ -1361,6 +1361,7 @@ static void init_inode(struct inode *inode, struct treepath *path) inode->i_fop = &reiserfs_dir_operations; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &reiserfs_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &reiserfs_address_space_operations; }else { inode->i_blocks =0 ;fs/reiserfs/namei.c +1
-0@@ -1170,6 +1170,7 @@ static int reiserfs_symlink(struct inode *parent_dir,reiserfs_update_inode_transaction (parent_dir); inode->i_op = &reiserfs_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &reiserfs_address_space_operations; retval = reiserfs_add_entry(&th, parent_dir, dentry->d_name.name,fs/romfs/super.c +1
-0@@ -360,6 +360,7 @@ static struct inode *romfs_iget(struct super_block *sb, unsigned long pos)break ;case ROMFH_SYM : i->i_op = &page_symlink_inode_operations; +inode_nohighmem (i); i->i_data.a_ops = &romfs_aops; mode |=S_IRWXUGO ;break ;fs/squashfs/inode.c +2
-0@@ -41,6 +41,7 @@#include <linux/fs.h> #include <linux/vfs.h> #include <linux/xattr.h> +#include <linux/pagemap.h> #include "squashfs_fs.h" #include "squashfs_fs_sb.h" @@ -291,6 +292,7 @@ int squashfs_read_inode(struct inode *inode, long long ino)set_nlink (inode,le32_to_cpu (sqsh_ino->nlink)); inode->i_size =le32_to_cpu (sqsh_ino->symlink_size); inode->i_op = &squashfs_symlink_inode_ops; +inode_nohighmem (inode); inode->i_data.a_ops = &squashfs_symlink_aops; inode->i_mode |=S_IFLNK ;squashfs_i (inode)->start = block;fs/sysv/inode.c +1
-0@@ -163,6 +163,7 @@ void sysv_set_inode(struct inode *inode, dev_t rdev) inode->i_mapping->a_ops = &sysv_aops; }else if (S_ISLNK (inode->i_mode)) { inode->i_op = &sysv_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &sysv_aops; }else init_special_inode (inode, inode->i_mode, rdev);fs/udf/inode.c +1
-0@@ -1541,6 +1541,7 @@ reread:case ICBTAG_FILE_TYPE_SYMLINK : inode->i_data.a_ops = &udf_symlink_aops; inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mode =S_IFLNK |S_IRWXUGO ;break ;case ICBTAG_FILE_TYPE_MAIN :fs/udf/namei.c +1
-0@@ -922,6 +922,7 @@ static int udf_symlink(struct inode *dir, struct dentry *dentry, inode->i_data.a_ops = &udf_symlink_aops; inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode);if (iinfo->i_alloc_type !=ICBTAG_FLAG_AD_IN_ICB ) {struct kernel_lb_addr eloc;fs/udf/symlink.c +1
-3@@ -107,7 +107,7 @@ static int udf_symlink_filler(struct file *file, struct page *page)struct buffer_head *bh =NULL ;unsigned char *symlink;int err; -unsigned char *p =kmap (page); +unsigned char *p =page_address (page);struct udf_inode_info *iinfo;uint32_t pos;@@ -141,7 +141,6 @@ static int udf_symlink_filler(struct file *file, struct page *page)up_read (&iinfo->i_data_sem);SetPageUptodate (page); -kunmap (page);unlock_page (page);return 0 ;@@ -149,7 +148,6 @@ out_unlock_inode:up_read (&iinfo->i_data_sem);SetPageError (page); out_unmap: -kunmap (page);unlock_page (page);return err; }fs/ufs/inode.c +1
-0@@ -533,6 +533,7 @@ static void ufs_set_inode_ops(struct inode *inode) }else { inode->i_mapping->a_ops = &ufs_aops; inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); } }else init_special_inode(inode, inode->i_mode,fs/ufs/namei.c +1
-0@@ -124,6 +124,7 @@ static int ufs_symlink (struct inode * dir, struct dentry * dentry,if (l >UFS_SB (sb)->s_uspi->s_maxsymlinklen) {/* slow symlink */ inode->i_op = &page_symlink_inode_operations; +inode_nohighmem (inode); inode->i_mapping->a_ops = &ufs_aops; err =page_symlink (inode, symname, l);if (err)include/linux/fs.h +1
-0@@ -3025,5 +3025,6 @@ static inline bool dir_relax(struct inode *inode) }extern bool path_noexec (const struct path *path); +extern void inode_nohighmem (struct inode *inode);#endif /* _LINUX_FS_H */ mm/shmem.c +3
-7@@ -2444,7 +2444,6 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *sint len;struct inode *inode;struct page *page; -char *kaddr;struct shmem_inode_info *info; len =strlen (symname) +1 ;@@ -2483,9 +2482,8 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s } inode->i_mapping->a_ops = &shmem_aops; inode->i_op = &shmem_symlink_inode_operations; - kaddr =kmap_atomic (page); -memcpy (kaddr, symname, len); -kunmap_atomic (kaddr); +inode_nohighmem (inode); +memcpy (page_address (page), symname, len);SetPageUptodate (page);set_page_dirty (page);unlock_page (page);@@ -2506,13 +2504,12 @@ static const char *shmem_follow_link(struct dentry *dentry, void **cookie)return ERR_PTR (error);unlock_page (page); *cookie = page; -return kmap (page); +return page_address (page); }static void shmem_put_link (struct inode *unused,void *cookie) {struct page *page = cookie; -kunmap (page);mark_page_accessed (page);page_cache_release (page); } --2.1.4
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Al Viro
maintainerRe: [PATCH v2 06/11] don't put symlink bodies in pagecache into highmem
Quoted 7 lines · Tomeu Vizoso
Quoted 6 lines · Al Viro
From: Al Viro <[email protected]>
kmap()inpage_follow_link_light()needed to go - allowing to hold an arbitrary number of kmaps for long is a great way to deadlocking the system.
Quoted 6 lines
Quoted 3 lines
new helper (
inode_nohighmem(inode)) needs to be used for pagecache symlinks inodes; done for all in-tree cases.page_follow_link_light()instrumented to yell about anything missed.Hi, starting with with this change, I get this oops when installing packages into a rootfs in NFS:
Lovely... So you somehow getting a highmem page out
page = read_cache_page(&inode->i_data, 0,
(filler_t *)nfs_symlink_filler, inode);
if (IS_ERR(page))
return ERR_CAST(page);
and that - after
inode_nohighmem(inode);(otherwise you wouldn't get nfs_symlink_inode_operations on that inode).
Could you add
printk(KERN_ERR "i_data = %p, i_mapping = %p, flags: %lx\n", &inode->i_data, inode->i_mapping, (unsigned long)inode->i_data.flags);
right before the return from nfs_get_link() and see what it prints?
Re: [PATCH v2 06/11] don't put symlink bodies in pagecache into highmem
Quoted 22 lines · Al Viro
Quoted 7 lines · Tomeu Vizoso
Quoted 6 lines · Al Viro
From: Al Viro <[email protected]>
kmap()inpage_follow_link_light()needed to go - allowing to hold an arbitrary number of kmaps for long is a great way to deadlocking the system.Quoted 6 lines
Quoted 3 lines
new helper (
inode_nohighmem(inode)) needs to be used for pagecache symlinks inodes; done for all in-tree cases.page_follow_link_light()instrumented to yell about anything missed.Hi, starting with with this change, I get this oops when installing packages into a rootfs in NFS:
Lovely... So you somehow getting a highmem page out
page = read_cache_page(&inode->i_data, 0, (filler_t *)nfs_symlink_filler, inode); if (IS_ERR(page)) return ERR_CAST(page); and that - after inode_nohighmem(inode);
Quoted 8 lines
(otherwise you wouldn't get
nfs_symlink_inode_operationson that inode).Could you add
printk(KERN_ERR "i_data = %p, i_mapping = %p, flags: %lx\n", &inode->i_data, inode->i_mapping, (unsigned long)inode->i_data.flags);right before the return from
nfs_get_link()and see what it prints?
Here it is:
[ 170.136956] i_data = ed9c1b04, i_mapping = ed9c1b04, flags: 24200c0
[ 170.144567] i_data = ed9de784, i_mapping = ed9de784, flags: 24200c0
[ 170.151457] i_data = ed9dec84, i_mapping = ed9dec84, flags: 24200c0
[ 170.158358] i_data = ed9c3b84, i_mapping = ed9c3b84, flags: 24200c0
[ 170.165253] i_data = ed9d4204, i_mapping = ed9d4204, flags: 24200c0
[ 170.172131] i_data = ed9df184, i_mapping = ed9df184, flags: 24200c0
[ 170.188804] i_data = eddbce84, i_mapping = eddbce84, flags: 24200c0
[ 170.196158] i_data = ec904984, i_mapping = ec904984, flags: 24200c0
[ 170.205133] i_data = ec906784, i_mapping = ec906784, flags: 24200c0
[ 170.211406] Unable to handle kernel NULL pointer dereference at
virtual address 00000000
[ 170.219490] pgd = ee7f0000
[ 170.222197] [00000000] *pgd=7b85b835
[ 170.225784] Internal error: Oops: 17 [#1] SMP ARM
[ 170.230477] Modules linked in:
[ 170.233537] CPU: 2 PID: 1 Comm: systemd Not tainted
4.4.0-next-20160114-00005-g6f86169c2250-dirty #3525
[ 170.242910] Hardware name: Rockchip (Device Tree)
[ 170.247604] task: ee078000 ti: ee062000 task.ti: ee062000
[ 170.252996] PC is at strlen+0x0/0x2c
[ 170.256565] LR is at readlink_copy+0x24/0x94
[ 170.260826] pc : [<c049b138>] lr : [<c0321160>] psr: 00000013
[ 170.260826] sp : ee063f38 ip : 00000000 fp : ec9066b0
[ 170.272281] r10: 001a49f8 r9 : 00000063 r8 : ee063f74
[ 170.277494] r7 : 001a4968 r6 : 001a49f8 r5 : 00000000 r4 : 00000063
[ 170.284008] r3 : 0000012c r2 : 00000000 r1 : 00000063 r0 : 00000000
[ 170.290522] Flags: nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
[ 170.297642] Control: 10c5387d Table: 2e7f006a DAC: 00000051
[ 170.303375] Process systemd (pid: 1, stack limit = 0xee062220)
[ 170.309196] Stack: (0xee063f38 to 0xee064000)
[ 170.313542] 3f20:
001a49f8 00000063
[ 170.321705] 3f40: ffffff9c 001a4968 ee063f74 c0321208 c0321250
eff6b920 ffffffea ffffffea
[ 170.329868] 3f60: 00004000 c031c234 00000000 00000000 00000025
00000000 ee102b50 ec874990
[ 170.338030] 3f80: 5697c41b 001a49f8 00000064 00000063 0000014c
c0210e84 ee062000 00000000
[ 170.346193] 3fa0: 001a4968 c0210cc0 001a49f8 00000064 ffffff9c
001a4968 001a49f8 00000063
[ 170.354355] 3fc0: 001a49f8 00000064 00000063 0000014c bec450b8
001c1094 001d0933 001a4968
[ 170.362518] 3fe0: 0000014c bec45094 b6f2af7b b6eb88e6 20000030
ffffff9c ffffffff ffeffffe
[ 170.370683] [<c049b138>] (strlen) from [<c0321160>] (readlink_copy+0x24/0x94)
[ 170.377806] [<c0321160>] (readlink_copy) from [<c0321208>]
(generic_readlink+0x38/0x80)
[ 170.385796] [<c0321208>] (generic_readlink) from [<c031c234>]
(SyS_readlinkat+0x98/0xe0)
[ 170.393874] [<c031c234>] (SyS_readlinkat) from [<c0210cc0>]
(ret_fast_syscall+0x0/0x3c)
[ 170.401863] Code: e7d23003 e3130020 1afffffb e12fff1e (e5d02000)
[ 170.407965] ---[ end trace 87f95166dedbabb0 ]---Full log at https://lava.collabora.co.uk/scheduler/job/127626/log_file
Regards,
Tomeu
Al Viro
maintainerRe: [PATCH v2 06/11] don't put symlink bodies in pagecache into highmem
Quoted 9 lines · Tomeu Vizoso
Quoted 6 lines
Could you add
printk(KERN_ERR "i_data = %p, i_mapping = %p, flags: %lx\n", &inode->i_data, inode->i_mapping, (unsigned long)inode->i_data.flags);right before the return from
nfs_get_link()and see what it prints?Here it is:
Quoted 9 lines
[ 170.136956] i_data = ed9c1b04, i_mapping = ed9c1b04, flags: 24200c0 [ 170.144567] i_data = ed9de784, i_mapping = ed9de784, flags: 24200c0 [ 170.151457] i_data = ed9dec84, i_mapping = ed9dec84, flags: 24200c0 [ 170.158358] i_data = ed9c3b84, i_mapping = ed9c3b84, flags: 24200c0 [ 170.165253] i_data = ed9d4204, i_mapping = ed9d4204, flags: 24200c0 [ 170.172131] i_data = ed9df184, i_mapping = ed9df184, flags: 24200c0 [ 170.188804] i_data = eddbce84, i_mapping = eddbce84, flags: 24200c0 [ 170.196158] i_data = ec904984, i_mapping = ec904984, flags: 24200c0 [ 170.205133] i_data = ec906784, i_mapping = ec906784, flags: 24200c0
Aha. So ->i_data vs. ->i_mapping is irrelevant (as it ought to be here) and inode_nohighmem() should've acted on the address_space we are hitting here. What do we have in flags... ___GFP_IO | ___GFP_FS | ___GFP_HARDWALL | ___GFP_DIRECT_RECLAIM | ___GFP_KSWAPD_RECLAIM. IOW, normal GFP_USER, no __GFP_HIGHMEM in sight.
So either we have a highmem page somehow ending up in i_data before we set the flags, or __page_cache_alloc() done by read_cache_page() returns us a highmem page on GFP_USER | __GFP_COLD (or I'm misreading the things completely)...
Could you slap
printk(KERN_ERR "inode: %p, pages: %ld\n", inode, inode->i_data.nrpages); before that read_cache_page() in nfs_get_link() and printk(KERN_ERR "page_address: %p\n", page_address(page));
right before the return?
Re: [PATCH v2 06/11] don't put symlink bodies in pagecache into highmem
Quoted 31 lines · Al Viro
Quoted 9 lines · Tomeu Vizoso
Quoted 6 lines
Could you add
printk(KERN_ERR "i_data = %p, i_mapping = %p, flags: %lx\n", &inode->i_data, inode->i_mapping, (unsigned long)inode->i_data.flags);right before the return from
nfs_get_link()and see what it prints?Here it is:
Quoted 9 lines
[ 170.136956] i_data = ed9c1b04, i_mapping = ed9c1b04, flags: 24200c0 [ 170.144567] i_data = ed9de784, i_mapping = ed9de784, flags: 24200c0 [ 170.151457] i_data = ed9dec84, i_mapping = ed9dec84, flags: 24200c0 [ 170.158358] i_data = ed9c3b84, i_mapping = ed9c3b84, flags: 24200c0 [ 170.165253] i_data = ed9d4204, i_mapping = ed9d4204, flags: 24200c0 [ 170.172131] i_data = ed9df184, i_mapping = ed9df184, flags: 24200c0 [ 170.188804] i_data = eddbce84, i_mapping = eddbce84, flags: 24200c0 [ 170.196158] i_data = ec904984, i_mapping = ec904984, flags: 24200c0 [ 170.205133] i_data = ec906784, i_mapping = ec906784, flags: 24200c0Aha. So ->i_data vs. ->i_mapping is irrelevant (as it ought to be here) and
inode_nohighmem()should've acted on theaddress_spacewe are hitting here. What do we have in flags...___GFP_IO|___GFP_FS|___GFP_HARDWALL|___GFP_DIRECT_RECLAIM|___GFP_KSWAPD_RECLAIM. IOW, normalGFP_USER, no__GFP_HIGHMEMin sight.So either we have a highmem page somehow ending up in
i_databefore we set the flags, or__page_cache_alloc()done byread_cache_page()returns us a highmem page onGFP_USER|__GFP_COLD(or I'm misreading the things completely)...
Quoted 6 lines
Could you slap
printk(KERN_ERR "inode: %p, pages: %ld\n", inode, inode->i_data.nrpages); before that read_cache_page() in nfs_get_link() and printk(KERN_ERR "page_address: %p\n", page_address(page));right before the return?
Here it is:
[ 170.715356] inode: ec8c30b0, pages: 1 [ 170.719014] page_address: (null)
https://lava.collabora.co.uk/scheduler/job/127698/log_file
Regards,
Tomeu
Al Viro
maintainerRe: [PATCH v2 06/11] don't put symlink bodies in pagecache into highmem
Quoted 6 lines · Tomeu Vizoso
Here it is:
[ 170.715356] inode: ec8c30b0, pages: 1 [ 170.719014] page_address: (null)
Lovely... And that looks like the first time that inode hitsnfs_get_link(). Ho-hum...
Could you add WARN_ON(inode->i_mapping.nrpages) in inode_nohighmem()
and see if that triggers? It really shouldn't (we hit it after iget5_locked() in nfs_fhget() has returned us a new inode, and there shouldn't be a chance for any pages to get in there between struct inode allocation and that point), but then neither should highmem pages be added to address_space without __GFP_HIGHMEM in ->flags...
Re: [PATCH v2 06/11] don't put symlink bodies in pagecache into highmem
Quoted 6 lines · Al Viro
Quoted 5 lines · Tomeu Vizoso
Here it is:
[ 170.715356] inode: ec8c30b0, pages: 1 [ 170.719014] page_address: (null)
Quoted 7 lines
Lovely... And that looks like the first time that inode hits
nfs_get_link(). Ho-hum...Could you add WARN_ON(inode->i_mapping.nrpages) in inode_nohighmem()and see if that triggers? It really shouldn't (we hit it after
iget5_locked()
Indeed :(
https://lava.collabora.co.uk/scheduler/job/127782/log_file
fs/inode.c +1 -0
@@ -2031,6 +2031,7 @@ EXPORT_SYMBOL(inode_set_flags);void inode_nohighmem (struct inode *inode) { +WARN_ON (inode->i_mapping->nrpages);mapping_set_gfp_mask (inode->i_mapping,GFP_USER ); }EXPORT_SYMBOL (inode_nohighmem);
I have ran out of time for today, but tomorrow can do more tests if needed.
Regards,
Tomeu
Quoted 4 lines
in
nfs_fhget()has returned us a new inode, and there shouldn't be a chance for any pages to get in there between struct inode allocation and that point), but then neither should highmem pages be added toaddress_spacewithout__GFP_HIGHMEMin ->flags...
Al Viro
maintainerRe: [PATCH v2 06/11] don't put symlink bodies in pagecache into highmem
Quoted 12 lines · Tomeu Vizoso
Quoted 11 lines · Al Viro
Quoted 6 lines · Tomeu Vizoso
Here it is:
[ 170.715356] inode: ec8c30b0, pages: 1 [ 170.719014] page_address: (null)Lovely... And that looks like the first time that inode hits
nfs_get_link(). Ho-hum...
Quoted 6 lines
Quoted 2 lines
Could you add WARN_ON(inode->i_mapping.nrpages) in inode_nohighmem()and see if that triggers? It really shouldn't (we hit it after
iget5_locked()Indeed :(
OK... Unless I'm misreading that, we have
* inode->i_data.flags set to GFP_USER, with no pages present in
there.
* at some later point nfs_get_link() is called on that inode
(for the first time) and sees a page with logical offset 0 already present in there, that page being a highmem one.
That would certainly suffice for the things to blow up...
Let's try this: in the beginning of __add_to_page_cache_locked() add
VM_BUG_ON_PAGE(PageHighMem(page) & !(mapping->flags & __GFP_HIGHMEM), page);
and see if that triggers.
<pokes around>
Arrrgh. Try this:
fs/nfs/dir.c +2 -3
@@ -1894,15 +1894,14 @@ int nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) attr.ia_mode =S_IFLNK |S_IRWXUGO ; attr.ia_valid =ATTR_MODE ; - page =alloc_page (GFP_HIGHUSER ); + page =alloc_page (GFP_USER );if (!page)return -ENOMEM ; - kaddr =kmap_atomic (page); + kaddr =page_address (page);memcpy (kaddr, symname, pathlen);if (pathlen <PAGE_SIZE )memset (kaddr + pathlen,0 ,PAGE_SIZE - pathlen); -kunmap_atomic (kaddr);trace_nfs_symlink_enter (dir, dentry); error =NFS_PROTO (dir)->symlink (dir, dentry, page, pathlen, &attr);
Re: [PATCH v2 06/11] don't put symlink bodies in pagecache into highmem
Quoted 2 lines · Al Viro
Arrrgh. Try this:
Yeah, that would do it.
Al, did you check any other filesystems do this?
Also, I'm wondering if we should perhaps revert the "don't use highmem". Do we actually have examples of running out of kmaps? Do we care?
Linus
Al Viro
maintainerRe: [PATCH v2 06/11] don't put symlink bodies in pagecache into highmem
Quoted 7 lines · Linus Torvalds
Quoted 2 lines · Al Viro
Arrrgh. Try this:
Yeah, that would do it.
Al, did you check any other filesystems do this?
There's one more turd like that - shmem should've done inode_nohighmem() a bit earlier in shmem_symlink(). The rest is OK.
Quoted 3 lines
Also, I'm wondering if we should perhaps revert the "don't use highmem". Do we actually have examples of running out of kmaps? Do we care?
For one thing, we'll lose RCU ->get_link() for those. For another... yes, it was a nasty bug (I missed the possibility that filesystem might seed the page cache on ->symlink() directly and use a highmem page - mea culpa), but we can easily catch it at runtime. We really shouldn't put highmem pages into address_space without __GFP_HIGHMEM, and catching those in __add_to_page_cache_locked() isn't costly.
Anyway, mm/shmem.c bit follows. With that + NFS one we ought to be OK wrt that class of bogosities. I'll write the bits for Documentation/filesystems/porting (basically, "if you preseed the pagecache at ->symlink() time, don't put highmem pages there; page_symlink() will take care of that, provided that inode_nohighmem() is called first") and push the combined patch to #for-linus.
mm/shmem.c +1 -1
@@ -2469,6 +2469,7 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s inode->i_op = &shmem_short_symlink_operations; inode->i_link = info->symlink; }else { +inode_nohighmem (inode); error =shmem_getpage (inode,0 , &page,SGP_WRITE ,NULL );if (error) {iput (inode);
@@ -2476,7 +2477,6 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s } inode->i_mapping->a_ops = &shmem_aops; inode->i_op = &shmem_symlink_inode_operations; -inode_nohighmem (inode);memcpy (page_address (page), symname, len);SetPageUptodate (page);set_page_dirty (page);
Al Viro
maintainerRe: [PATCH v2 06/11] don't put symlink bodies in pagecache into highmem
Quoted 6 lines · Al Viro
Anyway,
mm/shmem.cbit follows. With that + NFS one we ought to be OK wrt that class of bogosities. I'll write the bits forDocumentation/filesystems/porting(basically, "if you preseed the pagecache at ->symlink() time, don't put highmem pages there;page_symlink()will take care of that, provided thatinode_nohighmem()is called first") and push the combined patch to #for-linus.
Done and pushed. Please, pull fromgit://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git
Shortlog:
Al Viro (1):
Make sure that highmem pages are not added to symlink page cache
Diffstat:
Documentation/filesystems/porting | 6 +++++- fs/nfs/dir.c | 5 ++--- mm/shmem.c | 2 +- 3 files changed, 8 insertions(+), 5 deletions(-)
Re: [PATCH v2 06/11] don't put symlink bodies in pagecache into highmem
In reply to Al ViroQuoted 2 lines · Al Viro
For one thing, we'll lose RCU ->get_link() for those.
Why couldn't we just do that in the RCU walker? kmap should be fine..
That said, as long as you think it's ok now, I guess I don't care. Having some sanity testing in __add_to_page_cache_locked might be a good safety net.
Linus
Al Viro
maintainerRe: [PATCH v2 06/11] don't put symlink bodies in pagecache into highmem
Quoted 5 lines · Linus Torvalds
Quoted 2 lines · Al Viro
For one thing, we'll lose RCU ->get_link() for those.
Why couldn't we just do that in the RCU walker? kmap should be fine..
In map_new_virtual():
__set_current_state(TASK_UNINTERRUPTIBLE);
add_wait_queue(pkmap_map_wait, &wait);
unlock_kmap();
schedule();
remove_wait_queue(pkmap_map_wait, &wait);
lock_kmap();IOW, not in RCU mode ;-/
Quoted 3 lines
That said, as long as you think it's ok now, I guess I don't care. Having some sanity testing in
__add_to_page_cache_lockedmight be a good safety net.
That's better as a separate commit, IMO. The thing I'm not sure about is whether we want a BUG() in there - VM_WARN_ON(), perhaps? OTOH, we do have VM_BUG_ON_PAGE() in the same place already...
Al Viro
maintainerPATCH v2 7/11 replace ->follow_link() with new method that could stay in RCU mode
In reply to Al ViroFrom: Al Viro <[email protected]>
new method: ->get_link(); replacement of ->follow_link(). The differences are:
* inode and dentry are passed separately
* might be called both in RCU and non-RCU mode;
the former is indicated by passing it a NULL dentry.
* when called that way it isn't allowed to block
and should return ERR_PTR(-ECHILD) if it needs to be called
in non-RCU mode.
It's a flagday change - the old method is gone, all in-tree instances converted. Conversion isn't hard; said that, so far very few instances do not immediately bail out when called in RCU mode. That'll change in the next commits.
Signed-off-by Al Viro <[email protected]>
--- Documentation/filesystems/Locking | 4 +-- Documentation/filesystems/porting | 6 ++++ drivers/staging/lustre/lustre/llite/symlink.c | 8 +++-- fs/9p/vfs_inode.c | 17 +++++++--- fs/9p/vfs_inode_dotl.c | 14 ++++++--- fs/affs/symlink.c | 4 +-- fs/autofs4/symlink.c | 13 +++++--- fs/btrfs/inode.c | 2 +- fs/ceph/inode.c | 2 +- fs/cifs/cifsfs.c | 2 +- fs/cifs/cifsfs.h | 4 +-- fs/cifs/link.c | 6 ++-- fs/coda/cnode.c | 2 +- fs/configfs/symlink.c | 11 +++++-- fs/dcache.c | 2 +- fs/ecryptfs/inode.c | 12 +++++-- fs/ext2/symlink.c | 4 +-- fs/ext4/symlink.c | 13 +++++--- fs/f2fs/namei.c | 16 ++++++---- fs/fuse/dir.c | 9 ++++-- fs/gfs2/inode.c | 15 ++++++--- fs/hostfs/hostfs_kern.c | 10 ++++-- fs/jffs2/symlink.c | 2 +- fs/jfs/symlink.c | 4 +-- fs/kernfs/symlink.c | 11 +++++-- fs/libfs.c | 9 +++--- fs/minix/inode.c | 2 +- fs/namei.c | 45 +++++++++++++++++---------- fs/ncpfs/inode.c | 2 +- fs/nfs/symlink.c | 9 ++++-- fs/nilfs2/namei.c | 2 +- fs/ocfs2/symlink.c | 2 +- fs/overlayfs/inode.c | 12 ++++--- fs/proc/base.c | 22 +++++++------ fs/proc/inode.c | 7 +++-- fs/proc/namespaces.c | 9 ++++-- fs/proc/self.c | 9 ++++-- fs/proc/thread_self.c | 9 ++++-- fs/reiserfs/namei.c | 2 +- fs/squashfs/symlink.c | 2 +- fs/sysv/inode.c | 2 +- fs/ubifs/file.c | 2 +- fs/xfs/xfs_iops.c | 8 +++-- include/linux/fs.h | 6 ++-- mm/shmem.c | 12 ++++--- 45 files changed, 234 insertions(+), 132 deletions(-)
Documentation/filesystems/Locking +2 -2
@@ -50,7 +50,7 @@ prototypes: int (*rename2) (struct inode *, struct dentry *, struct inode *, struct dentry *, unsigned int); int (*readlink) (struct dentry *, char __user *,int); - const char *(*follow_link) (struct dentry *, void **); + const char *(*get_link) (struct dentry *, struct inode *, void **); void (*put_link) (struct inode *, void *); void (*truncate) (struct inode *); int (*permission) (struct inode *, int, unsigned int);
@@ -83,7 +83,7 @@ rmdir: yes (both) (see below) rename: yes (all) (see below) rename2: yes (all) (see below) readlink: no -follow_link: no +get_link: no put_link: no setattr: yes permission: no (may not block if called in rcu-walk mode)
Documentation/filesystems/porting +6 -0
@@ -509,3 +509,9 @@ in your dentry operations instead. any symlink that might use page_follow_link_light/page_put_link() must have inode_nohighmem(inode) called before anything might start playing with its pagecache. +-- +[mandatory] + ->follow_link() is replaced with ->get_link(); same API, except that + * ->get_link() gets inode as a separate argument + * ->get_link() may be called in RCU mode - in that case NULL + dentry is passed
drivers/staging/lustre/lustre/llite/symlink.c +5 -3
@@ -118,12 +118,14 @@ failed:return rc; } -static const char *ll_follow_link (struct dentry *dentry,void **cookie) +static const char *ll_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct inode *inode =d_inode (dentry);struct ptlrpc_request *request =NULL ;int rc;char *symname =NULL ; +if (!dentry) +return ERR_PTR (-ECHILD );CDEBUG (D_VFSTRACE ,"VFS Op\n" );ll_inode_size_lock (inode);
@@ -149,7 +151,7 @@ static void ll_put_link(struct inode *unused, void *cookie)struct inode_operations ll_fast_symlink_inode_operations = { .readlink = generic_readlink, .setattr = ll_setattr, - .follow_link = ll_follow_link, + .get_link = ll_get_link, .put_link = ll_put_link, .getattr = ll_getattr, .permission = ll_inode_permission,
fs/9p/vfs_inode.c +12 -5
@@ -1223,18 +1223,25 @@ ino_t v9fs_qid2ino(struct p9_qid *qid) }/** -* v9fs_vfs_follow_link - follow a symlink path +* v9fs_vfs_get_link - follow a symlink path * @dentry: dentry for symlink +* @inode: inode for symlink * @cookie: place to pass the data to put_link() */ -static const char *v9fs_vfs_follow_link (struct dentry *dentry,void **cookie) +static const char *v9fs_vfs_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct v9fs_session_info *v9ses =v9fs_dentry2v9ses (dentry); -struct p9_fid *fid =v9fs_fid_lookup (dentry); +struct v9fs_session_info *v9ses; +struct p9_fid *fid;struct p9_wstat *st;char *res; +if (!dentry) +return ERR_PTR (-ECHILD ); + + v9ses =v9fs_dentry2v9ses (dentry); + fid =v9fs_fid_lookup (dentry);p9_debug (P9_DEBUG_VFS ,"%pd\n" , dentry);if (IS_ERR (fid))
@@ -1452,7 +1459,7 @@ static const struct inode_operations v9fs_file_inode_operations = {static const struct inode_operations v9fs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = v9fs_vfs_follow_link, + .get_link = v9fs_vfs_get_link, .put_link = kfree_put_link, .getattr = v9fs_vfs_getattr, .setattr = v9fs_vfs_setattr,
fs/9p/vfs_inode_dotl.c +10 -4
@@ -899,20 +899,26 @@ error: }/** -* v9fs_vfs_follow_link_dotl - follow a symlink path +* v9fs_vfs_get_link_dotl - follow a symlink path * @dentry: dentry for symlink +* @inode: inode for symlink * @cookie: place to pass the data to put_link() */ static const char * -v9fs_vfs_follow_link_dotl (struct dentry *dentry,void **cookie) +v9fs_vfs_get_link_dotl (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct p9_fid *fid =v9fs_fid_lookup (dentry); +struct p9_fid *fid;char *target;int retval; +if (!dentry) +return ERR_PTR (-ECHILD ); +p9_debug (P9_DEBUG_VFS ,"%pd\n" , dentry); + fid =v9fs_fid_lookup (dentry);if (IS_ERR (fid))return ERR_CAST (fid); retval =p9_client_readlink (fid, &target);
@@ -984,7 +990,7 @@ const struct inode_operations v9fs_file_inode_operations_dotl = {const struct inode_operations v9fs_symlink_inode_operations_dotl = { .readlink = generic_readlink, - .follow_link = v9fs_vfs_follow_link_dotl, + .get_link = v9fs_vfs_get_link_dotl, .put_link = kfree_put_link, .getattr = v9fs_vfs_getattr_dotl, .setattr = v9fs_vfs_setattr_dotl,
fs/affs/symlink.c +2 -2
@@ -20,7 +20,7 @@ static int affs_symlink_readpage(struct file *file, struct page *page)char c;char lc; -pr_debug ("follow_link(ino=%lu)\n" , inode->i_ino); +pr_debug ("get_link(ino=%lu)\n" , inode->i_ino); bh =affs_bread (inode->i_sb, inode->i_ino);if (!bh)
@@ -71,7 +71,7 @@ const struct address_space_operations affs_symlink_aops = {const struct inode_operations affs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .setattr = affs_notify_change, };
fs/autofs4/symlink.c +9 -4
@@ -12,10 +12,15 @@#include "autofs_i.h" -static const char *autofs4_follow_link (struct dentry *dentry,void **cookie) +static const char *autofs4_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct autofs_sb_info *sbi =autofs4_sbi (dentry->d_sb); -struct autofs_info *ino =autofs4_dentry_ino (dentry); +struct autofs_sb_info *sbi; +struct autofs_info *ino; +if (!dentry) +return ERR_PTR (-ECHILD ); + sbi =autofs4_sbi (dentry->d_sb); + ino =autofs4_dentry_ino (dentry);if (ino && !autofs4_oz_mode (sbi)) ino->last_used = jiffies;return d_inode (dentry)->i_private;
@@ -23,5 +28,5 @@ static const char *autofs4_follow_link(struct dentry *dentry, void **cookie)const struct inode_operations autofs4_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = autofs4_follow_link + .get_link = autofs4_get_link };
fs/btrfs/inode.c +1 -1
@@ -10096,7 +10096,7 @@ static const struct inode_operations btrfs_special_inode_operations = { };static const struct inode_operations btrfs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .getattr = btrfs_getattr, .setattr = btrfs_setattr,
fs/ceph/inode.c +1 -1
@@ -1756,7 +1756,7 @@ retry:*/ static const struct inode_operations ceph_symlink_iops = { .readlink = generic_readlink, - .follow_link = simple_follow_link, + .get_link = simple_get_link, .setattr = ceph_setattr, .getattr = ceph_getattr, .setxattr = ceph_setxattr,
fs/cifs/cifsfs.c +1 -1
@@ -900,7 +900,7 @@ const struct inode_operations cifs_file_inode_ops = {const struct inode_operations cifs_symlink_inode_ops = { .readlink = generic_readlink, - .follow_link = cifs_follow_link, + .get_link = cifs_get_link, .put_link = kfree_put_link, .permission = cifs_permission,/* BB add the following two eventually */
fs/cifs/cifsfs.h +1 -3
@@ -120,9 +120,7 @@ extern struct vfsmount *cifs_dfs_d_automount(struct path *path);#endif /* Functions related to symlinks */ -extern const char *cifs_follow_link (struct dentry *direntry,void **cookie); -extern int cifs_readlink (struct dentry *direntry,char __user *buffer, -int buflen); +extern const char *cifs_get_link (struct dentry *,struct inode *,void **);extern int cifs_symlink (struct inode *inode,struct dentry *direntry,const char *symname);extern int cifs_removexattr (struct dentry *,const char *);
fs/cifs/link.c +4 -2
@@ -627,9 +627,8 @@ cifs_hl_exit: }const char * -cifs_follow_link (struct dentry *direntry,void **cookie) +cifs_get_link (struct dentry *direntry,struct inode *inode,void **cookie) { -struct inode *inode =d_inode (direntry);int rc = -ENOMEM ;unsigned int xid;char *full_path =NULL ;
@@ -639,6 +638,9 @@ cifs_follow_link(struct dentry *direntry, void **cookie)struct cifs_tcon *tcon;struct TCP_Server_Info *server; +if (!direntry) +return ERR_PTR (-ECHILD ); + xid =get_xid (); tlink =cifs_sb_tlink (cifs_sb);
fs/coda/cnode.c +1 -1
@@ -18,7 +18,7 @@ static inline int coda_fideq(struct CodaFid *fid1, struct CodaFid *fid2)static const struct inode_operations coda_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .setattr = coda_setattr, };
fs/configfs/symlink.c +8 -3
@@ -279,11 +279,16 @@ static int configfs_getlink(struct dentry *dentry, char * path) } -static const char *configfs_follow_link (struct dentry *dentry,void **cookie) +static const char *configfs_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -unsigned long page =get_zeroed_page (GFP_KERNEL ); +unsigned long page;int error; +if (!dentry) +return ERR_PTR (-ECHILD ); + + page =get_zeroed_page (GFP_KERNEL );if (!page)return ERR_PTR (-ENOMEM );
@@ -297,7 +302,7 @@ static const char *configfs_follow_link(struct dentry *dentry, void **cookie) }const struct inode_operations configfs_symlink_inode_operations = { - .follow_link = configfs_follow_link, + .get_link = configfs_get_link, .readlink = generic_readlink, .put_link = free_page_put_link, .setattr = configfs_setattr,
fs/dcache.c +1 -1
@@ -1734,7 +1734,7 @@ static unsigned d_flags_for_inode(struct inode *inode) }if (unlikely (!(inode->i_opflags &IOP_NOFOLLOW ))) { -if (unlikely (inode->i_op->follow_link)) { +if (unlikely (inode->i_op->get_link)) { add_flags =DCACHE_SYMLINK_TYPE ; goto type_determined; }
fs/ecryptfs/inode.c +9 -3
@@ -674,10 +674,16 @@ out:return rc ?ERR_PTR (rc) : buf; } -static const char *ecryptfs_follow_link (struct dentry *dentry,void **cookie) +static const char *ecryptfs_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) {size_t len; -char *buf =ecryptfs_readlink_lower (dentry, &len); +char *buf; + +if (!dentry) +return ERR_PTR (-ECHILD ); + + buf =ecryptfs_readlink_lower (dentry, &len);if (IS_ERR (buf))return buf; fsstack_copy_attr_atime(d_inode(dentry),
@@ -1095,7 +1101,7 @@ out:const struct inode_operations ecryptfs_symlink_iops = { .readlink = generic_readlink, - .follow_link = ecryptfs_follow_link, + .get_link = ecryptfs_get_link, .put_link = kfree_put_link, .permission = ecryptfs_permission, .setattr = ecryptfs_setattr,
fs/ext2/symlink.c +2 -2
@@ -22,7 +22,7 @@const struct inode_operations ext2_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .setattr = ext2_setattr, #ifdef CONFIG_EXT2_FS_XATTR
@@ -35,7 +35,7 @@ const struct inode_operations ext2_symlink_inode_operations = {const struct inode_operations ext2_fast_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = simple_follow_link, + .get_link = simple_get_link, .setattr = ext2_setattr, #ifdef CONFIG_EXT2_FS_XATTR .setxattr = generic_setxattr,
fs/ext4/symlink.c +8 -5
@@ -23,17 +23,20 @@#include "xattr.h" #ifdef CONFIG_EXT4_FS_ENCRYPTION -static const char *ext4_encrypted_follow_link (struct dentry *dentry,void **cookie) +static const char *ext4_encrypted_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) {struct page *cpage =NULL ;char *caddr, *paddr =NULL ;struct ext4_str cstr, pstr; -struct inode *inode =d_inode (dentry);struct ext4_encrypted_symlink_data *sd;loff_t size =min_t (loff_t,i_size_read (inode),PAGE_SIZE -1 );int res;u32 plen, max_size = inode->i_sb->s_blocksize; +if (!dentry) +return ERR_PTR (-ECHILD ); + res =ext4_get_encryption_info (inode);if (res)return ERR_PTR (res);
@@ -87,7 +90,7 @@ errout:const struct inode_operations ext4_encrypted_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = ext4_encrypted_follow_link, + .get_link = ext4_encrypted_get_link, .put_link = kfree_put_link, .setattr = ext4_setattr, .setxattr = generic_setxattr,
@@ -99,7 +102,7 @@ const struct inode_operations ext4_encrypted_symlink_inode_operations = {const struct inode_operations ext4_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .setattr = ext4_setattr, .setxattr = generic_setxattr,
@@ -110,7 +113,7 @@ const struct inode_operations ext4_symlink_inode_operations = {const struct inode_operations ext4_fast_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = simple_follow_link, + .get_link = simple_get_link, .setattr = ext4_setattr, .setxattr = generic_setxattr, .getxattr = generic_getxattr,
fs/f2fs/namei.c +10 -6
@@ -315,9 +315,10 @@ fail:return err; } -static const char *f2fs_follow_link (struct dentry *dentry,void **cookie) +static const char *f2fs_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -const char *link =page_follow_link_light (dentry, cookie); +const char *link =page_get_link (dentry, inode, cookie);if (!IS_ERR (link) && !*link) {/* this is broken symlink case */ page_put_link (NULL , *cookie);
@@ -924,18 +925,21 @@ static int f2fs_rename2(struct inode *old_dir, struct dentry *old_dentry, }#ifdef CONFIG_F2FS_FS_ENCRYPTION -static const char *f2fs_encrypted_follow_link (struct dentry *dentry,void **cookie) +static const char *f2fs_encrypted_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) {struct page *cpage =NULL ;char *caddr, *paddr =NULL ;struct f2fs_str cstr;struct f2fs_str pstr =FSTR_INIT (NULL ,0 ); -struct inode *inode =d_inode (dentry);struct f2fs_encrypted_symlink_data *sd;loff_t size =min_t (loff_t,i_size_read (inode),PAGE_SIZE -1 );u32 max_size = inode->i_sb->s_blocksize;int res; +if (!dentry) +return ERR_PTR (-ECHILD ); + res =f2fs_get_encryption_info (inode);if (res)return ERR_PTR (res);
@@ -994,7 +998,7 @@ errout:const struct inode_operations f2fs_encrypted_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = f2fs_encrypted_follow_link, + .get_link = f2fs_encrypted_get_link, .put_link = kfree_put_link, .getattr = f2fs_getattr, .setattr = f2fs_setattr,
@@ -1030,7 +1034,7 @@ const struct inode_operations f2fs_dir_inode_operations = {const struct inode_operations f2fs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = f2fs_follow_link, + .get_link = f2fs_get_link, .put_link = page_put_link, .getattr = f2fs_getattr, .setattr = f2fs_setattr,
fs/fuse/dir.c +6 -3
@@ -1365,14 +1365,17 @@ static int fuse_readdir(struct file *file, struct dir_context *ctx)return err; } -static const char *fuse_follow_link (struct dentry *dentry,void **cookie) +static const char *fuse_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct inode *inode =d_inode (dentry);struct fuse_conn *fc =get_fuse_conn (inode);FUSE_ARGS (args);char *link;ssize_t ret; +if (!dentry) +return ERR_PTR (-ECHILD ); + link = (char *)__get_free_page (GFP_KERNEL );if (!link)return ERR_PTR (-ENOMEM );
@@ -1909,7 +1912,7 @@ static const struct inode_operations fuse_common_inode_operations = {static const struct inode_operations fuse_symlink_inode_operations = { .setattr = fuse_setattr, - .follow_link = fuse_follow_link, + .get_link = fuse_get_link, .put_link = free_page_put_link, .readlink = generic_readlink, .getattr = fuse_getattr,
fs/gfs2/inode.c +10 -5
@@ -1712,24 +1712,29 @@ static int gfs2_rename2(struct inode *odir, struct dentry *odentry, }/** -* gfs2_follow_link - Follow a symbolic link +* gfs2_get_link - Follow a symbolic link * @dentry: The dentry of the link -* @nd: Data that we pass to vfs_follow_link() +* @inode: The inode of the link +* @cookie: place to store the information for ->put_link() * * This can handle symlinks of any size. * * Returns: 0 on success or error code */ -static const char *gfs2_follow_link (struct dentry *dentry,void **cookie) +static const char *gfs2_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct gfs2_inode *ip =GFS2_I (d_inode (dentry)); +struct gfs2_inode *ip =GFS2_I (inode);struct gfs2_holder i_gh;struct buffer_head *dibh;unsigned int size;char *buf;int error; +if (!dentry) +return ERR_PTR (-ECHILD ); +gfs2_holder_init (ip->i_gl,LM_ST_SHARED ,0 , &i_gh); error =gfs2_glock_nq (&i_gh);if (error) {
@@ -2132,7 +2137,7 @@ const struct inode_operations gfs2_dir_iops = {const struct inode_operations gfs2_symlink_iops = { .readlink = generic_readlink, - .follow_link = gfs2_follow_link, + .get_link = gfs2_get_link, .put_link = kfree_put_link, .permission = gfs2_permission, .setattr = gfs2_setattr,
fs/hostfs/hostfs_kern.c +7 -3
@@ -892,9 +892,13 @@ static const struct inode_operations hostfs_dir_iops = { .setattr = hostfs_setattr, }; -static const char *hostfs_follow_link (struct dentry *dentry,void **cookie) +static const char *hostfs_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -char *link =__getname (); +char *link; +if (!dentry) +return ERR_PTR (-ECHILD ); + link =__getname ();if (link) {char *path =dentry_name (dentry);int err = -ENOMEM ;
@@ -922,7 +926,7 @@ static void hostfs_put_link(struct inode *unused, void *cookie)static const struct inode_operations hostfs_link_iops = { .readlink = generic_readlink, - .follow_link = hostfs_follow_link, + .get_link = hostfs_get_link, .put_link = hostfs_put_link, };
fs/jffs2/symlink.c +1 -1
@@ -14,7 +14,7 @@const struct inode_operations jffs2_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = simple_follow_link, + .get_link = simple_get_link, .setattr = jffs2_setattr, .setxattr = jffs2_setxattr, .getxattr = jffs2_getxattr,
fs/jfs/symlink.c +2 -2
@@ -23,7 +23,7 @@const struct inode_operations jfs_fast_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = simple_follow_link, + .get_link = simple_get_link, .setattr = jfs_setattr, .setxattr = jfs_setxattr, .getxattr = jfs_getxattr,
@@ -33,7 +33,7 @@ const struct inode_operations jfs_fast_symlink_inode_operations = {const struct inode_operations jfs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .setattr = jfs_setattr, .setxattr = jfs_setxattr,
fs/kernfs/symlink.c +8 -3
@@ -112,10 +112,15 @@ static int kernfs_getlink(struct dentry *dentry, char *path)return error; } -static const char *kernfs_iop_follow_link (struct dentry *dentry,void **cookie) +static const char *kernfs_iop_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) {int error = -ENOMEM ; -unsigned long page =get_zeroed_page (GFP_KERNEL ); +unsigned long page; + +if (!dentry) +return ERR_PTR (-ECHILD ); + page =get_zeroed_page (GFP_KERNEL );if (!page)return ERR_PTR (-ENOMEM ); error =kernfs_getlink (dentry, (char *)page);
@@ -132,7 +137,7 @@ const struct inode_operations kernfs_symlink_iops = { .getxattr = kernfs_iop_getxattr, .listxattr = kernfs_iop_listxattr, .readlink = generic_readlink, - .follow_link = kernfs_iop_follow_link, + .get_link = kernfs_iop_get_link, .put_link = free_page_put_link, .setattr = kernfs_iop_setattr, .getattr = kernfs_iop_getattr,
fs/libfs.c +5 -4
@@ -1092,14 +1092,15 @@ simple_nosetlease(struct file *filp, long arg, struct file_lock **flp, }EXPORT_SYMBOL (simple_nosetlease); -const char *simple_follow_link (struct dentry *dentry,void **cookie) +const char *simple_get_link (struct dentry *dentry,struct inode *inode, +void **cookie) { -return d_inode (dentry)->i_link; +return inode->i_link; } -EXPORT_SYMBOL (simple_follow_link); +EXPORT_SYMBOL (simple_get_link);const struct inode_operations simple_symlink_inode_operations = { - .follow_link = simple_follow_link, + .get_link = simple_get_link, .readlink = generic_readlink };EXPORT_SYMBOL (simple_symlink_inode_operations);
fs/minix/inode.c +1 -1
@@ -435,7 +435,7 @@ static const struct address_space_operations minix_aops = {static const struct inode_operations minix_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .getattr = minix_getattr, };
fs/namei.c +28 -17
100 lines not on this page · raw message
fs/ncpfs/inode.c +1 -1
@@ -244,7 +244,7 @@ static void ncp_set_attr(struct inode *inode, struct ncp_entry_info *nwinfo)#if defined(CONFIG_NCPFS_EXTRAS ) || defined(CONFIG_NCPFS_NFS_NS )static const struct inode_operations ncp_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .setattr = ncp_notify_change, };
fs/nfs/symlink.c +6 -3
@@ -42,12 +42,15 @@ error:return -EIO ; } -static const char *nfs_follow_link (struct dentry *dentry,void **cookie) +static const char *nfs_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct inode *inode =d_inode (dentry);struct page *page;void *err; +if (!dentry) +return ERR_PTR (-ECHILD ); + err =ERR_PTR (nfs_revalidate_mapping (inode, inode->i_mapping));if (err)return err;
@@ -64,7 +67,7 @@ static const char *nfs_follow_link(struct dentry *dentry, void **cookie)*/ const struct inode_operations nfs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = nfs_follow_link, + .get_link = nfs_get_link, .put_link = page_put_link, .getattr = nfs_getattr, .setattr = nfs_setattr,
fs/nilfs2/namei.c +1 -1
@@ -569,7 +569,7 @@ const struct inode_operations nilfs_special_inode_operations = {const struct inode_operations nilfs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .permission = nilfs_permission, };
fs/ocfs2/symlink.c +1 -1
@@ -88,7 +88,7 @@ const struct address_space_operations ocfs2_fast_symlink_aops = {const struct inode_operations ocfs2_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .getattr = ocfs2_getattr, .setattr = ocfs2_setattr,
fs/overlayfs/inode.c +8 -4
@@ -137,17 +137,21 @@ struct ovl_link_data {void *cookie; }; -static const char *ovl_follow_link (struct dentry *dentry,void **cookie) +static const char *ovl_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) {struct dentry *realdentry;struct inode *realinode;struct ovl_link_data *data =NULL ;const char *ret; +if (!dentry) +return ERR_PTR (-ECHILD ); + realdentry =ovl_dentry_real (dentry); realinode = realdentry->d_inode; -if (WARN_ON (!realinode->i_op->follow_link)) +if (WARN_ON (!realinode->i_op->get_link))return ERR_PTR (-EPERM );if (realinode->i_op->put_link) {
@@ -157,7 +161,7 @@ static const char *ovl_follow_link(struct dentry *dentry, void **cookie) data->realdentry = realdentry; } - ret = realinode->i_op->follow_link (realdentry, cookie); + ret = realinode->i_op->get_link (realdentry, realinode, cookie);if (IS_ERR_OR_NULL (ret)) {kfree (data);return ret;
@@ -378,7 +382,7 @@ static const struct inode_operations ovl_file_inode_operations = {static const struct inode_operations ovl_symlink_inode_operations = { .setattr = ovl_setattr, - .follow_link = ovl_follow_link, + .get_link = ovl_get_link, .put_link = ovl_put_link, .readlink = ovl_readlink, .getattr = ovl_getattr,
fs/proc/base.c +13 -9
@@ -1564,12 +1564,15 @@ static int proc_exe_link(struct dentry *dentry, struct path *exe_path)return -ENOENT ; } -static const char *proc_pid_follow_link (struct dentry *dentry,void **cookie) +static const char *proc_pid_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct inode *inode =d_inode (dentry);struct path path;int error = -EACCES ; +if (!dentry) +return ERR_PTR (-ECHILD ); +/* Are we allowed to snoop on the tasks file descriptors? */ if (!proc_fd_access_allowed (inode)) goto out;
@@ -1630,7 +1633,7 @@ out:const struct inode_operations proc_pid_link_inode_operations = { .readlink = proc_pid_readlink, - .follow_link = proc_pid_follow_link, + .get_link = proc_pid_get_link, .setattr = proc_setattr, };
@@ -1895,7 +1898,7 @@ static const struct dentry_operations tid_map_files_dentry_operations = { .d_delete = pid_delete_dentry, }; -static int proc_map_files_get_link (struct dentry *dentry,struct path *path) +static int map_files_get_link (struct dentry *dentry,struct path *path) {unsigned long vm_start, vm_end;struct vm_area_struct *vma;
@@ -1945,20 +1948,21 @@ struct map_files_info {* path to the file in question. */ static const char * -proc_map_files_follow_link (struct dentry *dentry,void **cookie) +proc_map_files_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) {if (!capable (CAP_SYS_ADMIN ))return ERR_PTR (-EPERM ); -return proc_pid_follow_link (dentry,NULL ); +return proc_pid_get_link (dentry, inode,NULL ); }/* -* Identical to proc_pid_link_inode_operations except for follow_link() +* Identical to proc_pid_link_inode_operations except for get_link() */ static const struct inode_operations proc_map_files_link_inode_operations = { .readlink = proc_pid_readlink, - .follow_link = proc_map_files_follow_link, + .get_link = proc_map_files_get_link, .setattr = proc_setattr, };
@@ -1975,7 +1979,7 @@ proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,return -ENOENT ; ei =PROC_I (inode); - ei->op.proc_get_link = proc_map_files_get_link; + ei->op.proc_get_link = map_files_get_link; inode->i_op = &proc_map_files_link_inode_operations; inode->i_size =64 ;
fs/proc/inode.c +4 -3
@@ -393,9 +393,10 @@ static const struct file_operations proc_reg_file_ops_no_compat = { };#endif -static const char *proc_follow_link (struct dentry *dentry,void **cookie) +static const char *proc_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct proc_dir_entry *pde =PDE (d_inode (dentry)); +struct proc_dir_entry *pde =PDE (inode);if (unlikely (!use_pde (pde)))return ERR_PTR (-EINVAL ); *cookie = pde;
@@ -409,7 +410,7 @@ static void proc_put_link(struct inode *unused, void *p)const struct inode_operations proc_link_inode_operations = { .readlink = generic_readlink, - .follow_link = proc_follow_link, + .get_link = proc_get_link, .put_link = proc_put_link, };
fs/proc/namespaces.c +6 -3
@@ -30,14 +30,17 @@ static const struct proc_ns_operations *ns_entries[] = { &mntns_operations, }; -static const char *proc_ns_follow_link (struct dentry *dentry,void **cookie) +static const char *proc_ns_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct inode *inode =d_inode (dentry);const struct proc_ns_operations *ns_ops =PROC_I (inode)->ns_ops;struct task_struct *task;struct path ns_path;void *error =ERR_PTR (-EACCES ); +if (!dentry) +return ERR_PTR (-ECHILD ); + task =get_proc_task (inode);if (!task)return error;
@@ -74,7 +77,7 @@ static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflstatic const struct inode_operations proc_ns_link_inode_operations = { .readlink = proc_ns_readlink, - .follow_link = proc_ns_follow_link, + .get_link = proc_ns_get_link, .setattr = proc_setattr, };
fs/proc/self.c +6 -3
@@ -18,12 +18,15 @@ static int proc_self_readlink(struct dentry *dentry, char __user *buffer,return readlink_copy (buffer, buflen, tmp); } -static const char *proc_self_follow_link (struct dentry *dentry,void **cookie) +static const char *proc_self_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct pid_namespace *ns = dentry->d_sb->s_fs_info; +struct pid_namespace *ns = inode->i_sb->s_fs_info;pid_t tgid =task_tgid_nr_ns (current, ns);char *name; +if (!dentry) +return ERR_PTR (-ECHILD );if (!tgid)return ERR_PTR (-ENOENT );/* 11 for max length of signed int in decimal + NULL term */
@@ -36,7 +39,7 @@ static const char *proc_self_follow_link(struct dentry *dentry, void **cookie)static const struct inode_operations proc_self_inode_operations = { .readlink = proc_self_readlink, - .follow_link = proc_self_follow_link, + .get_link = proc_self_get_link, .put_link = kfree_put_link, };
fs/proc/thread_self.c +6 -3
@@ -19,13 +19,16 @@ static int proc_thread_self_readlink(struct dentry *dentry, char __user *buffer,return readlink_copy (buffer, buflen, tmp); } -static const char *proc_thread_self_follow_link (struct dentry *dentry,void **cookie) +static const char *proc_thread_self_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) { -struct pid_namespace *ns = dentry->d_sb->s_fs_info; +struct pid_namespace *ns = inode->i_sb->s_fs_info;pid_t tgid =task_tgid_nr_ns (current, ns);pid_t pid =task_pid_nr_ns (current, ns);char *name; +if (!dentry) +return ERR_PTR (-ECHILD );if (!pid)return ERR_PTR (-ENOENT ); name =kmalloc (PROC_NUMBUF +6 +PROC_NUMBUF ,GFP_KERNEL );
@@ -37,7 +40,7 @@ static const char *proc_thread_self_follow_link(struct dentry *dentry, void **costatic const struct inode_operations proc_thread_self_inode_operations = { .readlink = proc_thread_self_readlink, - .follow_link = proc_thread_self_follow_link, + .get_link = proc_thread_self_get_link, .put_link = kfree_put_link, };
fs/reiserfs/namei.c +1 -1
@@ -1665,7 +1665,7 @@ const struct inode_operations reiserfs_dir_inode_operations = {*/ const struct inode_operations reiserfs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .setattr = reiserfs_setattr, .setxattr = reiserfs_setxattr,
fs/squashfs/symlink.c +1 -1
@@ -119,7 +119,7 @@ const struct address_space_operations squashfs_symlink_aops = {const struct inode_operations squashfs_symlink_inode_ops = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .getxattr = generic_getxattr, .listxattr = squashfs_listxattr
fs/sysv/inode.c +1 -1
@@ -146,7 +146,7 @@ static inline void write3byte(struct sysv_sb_info *sbi,static const struct inode_operations sysv_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = page_follow_link_light, + .get_link = page_get_link, .put_link = page_put_link, .getattr = sysv_getattr, };
fs/ubifs/file.c +1 -1
@@ -1608,7 +1608,7 @@ const struct inode_operations ubifs_file_inode_operations = {const struct inode_operations ubifs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = simple_follow_link, + .get_link = simple_get_link, .setattr = ubifs_setattr, .getattr = ubifs_getattr, .setxattr = ubifs_setxattr,
fs/xfs/xfs_iops.c +6 -2
@@ -414,13 +414,17 @@ xfs_vn_rename(* uio is kmalloced for this reason... */ STATIC const char * -xfs_vn_follow_link ( +xfs_vn_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) {char *link;int error = -ENOMEM ; +if (!dentry) +return ERR_PTR (-ECHILD ); + link =kmalloc (MAXPATHLEN +1 ,GFP_KERNEL );if (!link) goto out_err;
@@ -1172,7 +1176,7 @@ static const struct inode_operations xfs_dir_ci_inode_operations = {static const struct inode_operations xfs_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = xfs_vn_follow_link, + .get_link = xfs_vn_get_link, .put_link = kfree_put_link, .getattr = xfs_vn_getattr, .setattr = xfs_vn_setattr,
include/linux/fs.h +3 -3
@@ -1633,7 +1633,7 @@ struct file_operations {struct inode_operations {struct dentry * (*lookup) (struct inode *,struct dentry *,unsigned int ); -const char * (*follow_link) (struct dentry *,void **); +const char * (*get_link) (struct dentry *,struct inode *,void **);int (*permission) (struct inode *,int );struct posix_acl * (*get_acl)(struct inode *,int );
@@ -2736,7 +2736,7 @@ extern const struct file_operations generic_ro_fops;extern int readlink_copy (char __user *,int ,const char *);extern int page_readlink (struct dentry *,char __user *,int ); -extern const char *page_follow_link_light (struct dentry *,void **); +extern const char *page_get_link (struct dentry *,struct inode *,void **);extern void page_put_link (struct inode *,void *);extern int __page_symlink (struct inode *inode,const char *symname,int len,int nofs);
@@ -2754,7 +2754,7 @@ void __inode_sub_bytes(struct inode *inode, loff_t bytes);void inode_sub_bytes (struct inode *inode,loff_t bytes);loff_t inode_get_bytes (struct inode *inode);void inode_set_bytes (struct inode *inode,loff_t bytes); -const char *simple_follow_link (struct dentry *,void **); +const char *simple_get_link (struct dentry *,struct inode *,void **);extern const struct inode_operations simple_symlink_inode_operations;extern int iterate_dir (struct file *,struct dir_context *);
mm/shmem.c +8 -4
@@ -2496,10 +2496,14 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *sreturn 0 ; } -static const char *shmem_follow_link (struct dentry *dentry,void **cookie) +static const char *shmem_get_link (struct dentry *dentry, +struct inode *inode,void **cookie) {struct page *page =NULL ; -int error =shmem_getpage (d_inode (dentry),0 , &page,SGP_READ ,NULL ); +int error; +if (!dentry) +return ERR_PTR (-ECHILD ); + error =shmem_getpage (inode,0 , &page,SGP_READ ,NULL );if (error)return ERR_PTR (error);unlock_page (page);
@@ -2656,7 +2660,7 @@ static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size)static const struct inode_operations shmem_short_symlink_operations = { .readlink = generic_readlink, - .follow_link = simple_follow_link, + .get_link = simple_get_link, #ifdef CONFIG_TMPFS_XATTR .setxattr = shmem_setxattr, .getxattr = shmem_getxattr,
@@ -2667,7 +2671,7 @@ static const struct inode_operations shmem_short_symlink_operations = {static const struct inode_operations shmem_symlink_inode_operations = { .readlink = generic_readlink, - .follow_link = shmem_follow_link, + .get_link = shmem_get_link, .put_link = shmem_put_link, #ifdef CONFIG_TMPFS_XATTR .setxattr = shmem_setxattr,
Signature · 1 line
2.1.4
Al Viro
maintainerPATCH v2 8/11 teach page_get_link() to work in RCU mode
In reply to Al ViroFrom: Al Viro <[email protected]>
more or less along the lines of Neil's patchset, sans the insanity around kmap().
Signed-off-by Al Viro <[email protected]>
--- fs/namei.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-)
fs/namei.c +13 -6
@@ -4533,12 +4533,19 @@ const char *page_get_link(struct dentry *dentry, struct inode *inode,struct page *page;struct address_space *mapping = inode->i_mapping; -if (!dentry) -return ERR_PTR (-ECHILD ); - - page =read_mapping_page (mapping,0 ,NULL ); -if (IS_ERR (page)) -return (char *)page; +if (!dentry) { + page =find_get_page (mapping,0 ); +if (!page) +return ERR_PTR (-ECHILD ); +if (!PageUptodate (page)) { +put_page (page); +return ERR_PTR (-ECHILD ); + } + }else { + page =read_mapping_page (mapping,0 ,NULL ); +if (IS_ERR (page)) +return (char *)page; + } *cookie = page;BUG_ON (mapping_gfp_mask (mapping) & __GFP_HIGHMEM); kaddr =page_address (page);
Signature · 1 line
2.1.4
Al Viro
maintainerPATCH v2 9/11 teach shmem_get_link() to work in RCU mode
In reply to Al ViroFrom: Al Viro <[email protected]>
Signed-off-by Al Viro <[email protected]>
--- mm/shmem.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-)
mm/shmem.c +14 -6
@@ -2501,12 +2501,20 @@ static const char *shmem_get_link(struct dentry *dentry, {struct page *page =NULL ;int error; -if (!dentry) -return ERR_PTR (-ECHILD ); - error =shmem_getpage (inode,0 , &page,SGP_READ ,NULL ); -if (error) -return ERR_PTR (error); -unlock_page (page); +if (!dentry) { + page =find_get_page (inode->i_mapping,0 ); +if (!page) +return ERR_PTR (-ECHILD ); +if (!PageUptodate (page)) { +put_page (page); +return ERR_PTR (-ECHILD ); + } + }else { + error =shmem_getpage (inode,0 , &page,SGP_READ ,NULL ); +if (error) +return ERR_PTR (error); +unlock_page (page); + } *cookie = page;return page_address (page); }
Signature · 1 line
2.1.4
Al Viro
maintainerPATCH v2 10/11 teach proc_self_get_link()/proc_thread_self_get_link() to work in RCU mode
In reply to Al ViroFrom: Al Viro <[email protected]>
Signed-off-by Al Viro <[email protected]>
--- fs/proc/self.c | 8 +++----- fs/proc/thread_self.c | 9 ++++----- 2 files changed, 7 insertions(+), 10 deletions(-)
fs/proc/self.c +3 -5
@@ -25,14 +25,12 @@ static const char *proc_self_get_link(struct dentry *dentry,pid_t tgid =task_tgid_nr_ns (current, ns);char *name; -if (!dentry) -return ERR_PTR (-ECHILD );if (!tgid)return ERR_PTR (-ENOENT );/* 11 for max length of signed int in decimal + NULL term */ - name =kmalloc (12 ,GFP_KERNEL ); -if (!name) -return ERR_PTR (-ENOMEM ); + name =kmalloc (12 , dentry ?GFP_KERNEL :GFP_ATOMIC ); +if (unlikely (!name)) +return dentry ?ERR_PTR (-ENOMEM ) :ERR_PTR (-ECHILD );sprintf (name,"%d" , tgid);return *cookie = name; }
fs/proc/thread_self.c +4 -5
@@ -27,13 +27,12 @@ static const char *proc_thread_self_get_link(struct dentry *dentry,pid_t pid =task_pid_nr_ns (current, ns);char *name; -if (!dentry) -return ERR_PTR (-ECHILD );if (!pid)return ERR_PTR (-ENOENT ); - name =kmalloc (PROC_NUMBUF +6 +PROC_NUMBUF ,GFP_KERNEL ); -if (!name) -return ERR_PTR (-ENOMEM ); + name =kmalloc (PROC_NUMBUF +6 +PROC_NUMBUF , + dentry ?GFP_KERNEL :GFP_ATOMIC ); +if (unlikely (!name)) +return dentry ?ERR_PTR (-ENOMEM ) :ERR_PTR (-ECHILD );sprintf (name,"%d/task/%d" , tgid, pid);return *cookie = name; }
Signature · 1 line
2.1.4
Al Viro
maintainerPATCH v2 11/11 teach nfs_get_link() to work in RCU mode
In reply to Al ViroFrom: Al Viro <[email protected]>
based upon the corresponding patch from Neil's March patchset, again with kmap-related horrors removed.
Signed-off-by Al Viro <[email protected]>
--- fs/nfs/inode.c | 21 +++++++++++++++++++++ fs/nfs/symlink.c | 30 ++++++++++++++++++++---------- include/linux/nfs_fs.h | 1 + 3 files changed, 42 insertions(+), 10 deletions(-)
fs/nfs/inode.c +21 -0
@@ -1087,6 +1087,27 @@ static bool nfs_mapping_need_revalidate_inode(struct inode *inode) || NFS_STALE(inode); } +int nfs_revalidate_mapping_rcu (struct inode *inode) +{ +struct nfs_inode *nfsi =NFS_I (inode); +unsigned long *bitlock = &nfsi->flags; +int ret =0 ; + +if (IS_SWAPFILE (inode)) + goto out; +if (nfs_mapping_need_revalidate_inode (inode)) { + ret = -ECHILD ; + goto out; + } +spin_lock (&inode->i_lock); +if (test_bit (NFS_INO_INVALIDATING , bitlock) || + (nfsi->cache_validity &NFS_INO_INVALID_DATA )) + ret = -ECHILD ; +spin_unlock (&inode->i_lock); +out: +return ret; +} +/** * __nfs_revalidate_mapping - Revalidate the pagecache * @inode - pointer to host inode
fs/nfs/symlink.c +20 -10
@@ -48,16 +48,26 @@ static const char *nfs_get_link(struct dentry *dentry,struct page *page;void *err; -if (!dentry) -return ERR_PTR (-ECHILD ); - - err =ERR_PTR (nfs_revalidate_mapping (inode, inode->i_mapping)); -if (err) -return err; - page =read_cache_page (&inode->i_data,0 , - (filler_t *)nfs_symlink_filler, inode); -if (IS_ERR (page)) -return ERR_CAST (page); +if (!dentry) { + err =ERR_PTR (nfs_revalidate_mapping_rcu (inode)); +if (err) +return err; + page =find_get_page (inode->i_mapping,0 ); +if (!page) +return ERR_PTR (-ECHILD ); +if (!PageUptodate (page)) { +put_page (page); +return ERR_PTR (-ECHILD ); + } + }else { + err =ERR_PTR (nfs_revalidate_mapping (inode, inode->i_mapping)); +if (err) +return err; + page =read_cache_page (&inode->i_data,0 , + (filler_t *)nfs_symlink_filler, inode); +if (IS_ERR (page)) +return ERR_CAST (page); + } *cookie = page;return page_address (page); }
include/linux/nfs_fs.h +1 -0
@@ -359,6 +359,7 @@ extern int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode);extern int nfs_revalidate_inode_rcu (struct nfs_server *server,struct inode *inode);extern int __nfs_revalidate_inode (struct nfs_server *,struct inode *);extern int nfs_revalidate_mapping (struct inode *inode,struct address_space *mapping); +extern int nfs_revalidate_mapping_rcu (struct inode *inode);extern int nfs_revalidate_mapping_protected (struct inode *inode,struct address_space *mapping);extern int nfs_setattr (struct dentry *,struct iattr *);extern void nfs_setattr_update_inode (struct inode *inode,struct iattr *attr,struct nfs_fattr *);
Signature · 1 line
2.1.4
Quoted 3 lines · Al Viro
Any help with review and testing would be welcome. FWIW, it seems to survive the beating here.
It looks ok to me, but I *hate* that "cookie" thing we have. And I don't actually see any reason for it.
Every single user except for a couple seem to just put the resulting symlink address into the cookie (and then put_link() will kfree it or put_page() it). And the calling convention would be *so* much clearer if we just made things be
char *get_link(dentry, inode); put_link(dentry, inode, char *);
and get rid of that cookie entirely.
The only users of the cookie seem to be
- we currently use it for the page pointer vs the page data address.
That's because of the HIGHMEM crap that you removed. Without
highmem, the page data address specifies the page fine without any cookie.
- overlayfs, which uses it to create a temporary data storage.
Why? Mainly because it wants to hide the cookie in there. D'oh!
- proc, which uses it to save the proc_dir_entry
Why? The reason seems to be that we don't call put_link() with the
dentry that get_link got, so it can't look it up the sane way.
In other words, as far as I can tell, the cookie is just garbage now.
But maybe I missed something.
Other than that, I like the series. And I realize that technically the "cookie removal" would be a separate thing, but since you're changing the calling convention from "follow_link()" to "get_link()" in this series, I _really_ think that as part of that calling convention change we should just get rid of the cookie, rather than have *another* calling convention change later.
Hmm?
Linus
Al Viro
maintainerQuoted 7 lines · Linus Torvalds
That's because of the HIGHMEM crap that you removed. Without
highmem, the page data address specifies the page fine without any cookie.- overlayfs, which uses it to create a temporary data storage.
Why? Mainly because it wants to hide the cookie in there. D'oh!
Not really - it also wants to stash a way to underlying inode in there. See below...
Quoted 4 lines
- proc, which uses it to save the
proc_dir_entryWhy? The reason seems to be that we don't call
put_link()with the
dentry thatget_linkgot, so it can't look it up the sane way.
What's more, that dentry might very well have gone negative by that point. Think what happens if, during the symlink traversal, we run into the hard "restart from scratch in non-RCU mode". We'll need to do ->put_link() on everything we have in stack. Regardless of what might've happened to dentries/inodes of symlinks involved - all we are really promised is that RCU-delayed parts of their destruction hadn't been entered yet.
Note, BTW, that *all* ->put_link() instances ignore the inode argument and I seriously considered dropping it completely.
Al Viro
maintainerQuoted 10 lines · Al Viro
What's more, that dentry might very well have gone negative by that point. Think what happens if, during the symlink traversal, we run into the hard "restart from scratch in non-RCU mode". We'll need to do ->put_link() on everything we have in stack. Regardless of what might've happened to dentries/inodes of symlinks involved - all we are really promised is that RCU-delayed parts of their destruction hadn't been entered yet.
Note, BTW, that *all* ->put_link() instances ignore the inode argument and I seriously considered dropping it completely.
PS: I toyed with the idea of replacing cookie a struct callback_head, to make it really obvious what's going on - we are leaving a closure to be evaluated once the caller is done with our return value. That way ->put_link() as a method would've been gone and we would've had something like
init_callback(destructor, page_put_link, page); instead of *cookie = page;
plus
.put_link = page_put_link,
we have right now, etc.
The reason not to go that way (and not all that strong, at that) is that we get an extra pointer in struct saved, i.e. slightly heavier nameidata (there are two struct saved embedded into it). That, or play silly buggers with
union {
struct callback_head callback;
struct inode *inode;
};in struct saved - we need to stash a pointer to inode between pick_link() and get_link().
Hell knows, still might make sense to go there... What we want is to set a closure to be evaluated once the caller of ->get_link() is done with the string ->get_link() returns. We end up picking the function to be called at saved->inode->i_op->put_link and store its argument in saved->cookie. Might as well just use the representation we use for such stuff (rcu_head, etc.) and be done with that...
Al Viro
maintainerQuoted 1 line · Al Viro
PS: I toyed with the idea of replacing cookie a struct
callback_head, to make
... except that it would have to be something like work_struct, since callback_head gets embedded into the argument and here we don't want to do that. _And_ we've no use for ->entry in work_struct, which makes it a bad fit as well. IOW, please ignore that idiocy...
Al Viro
maintainerQuoted 4 lines · Al Viro
... except that it would have to be something like
work_struct, sincecallback_headgets embedded into the argument and here we don't want to do that. _And_ we've no use for ->entry inwork_struct, which makes it a bad fit as well. IOW, please ignore that idiocy...
OK, the following (incremental to that series) seems to be better; in particular, overlayfs ->get_link() doesn't allocate anything whatsoever, ->put_link() as a method is gone and instead of *cookie = <something that will make sense for our put_link> we do
set_delayed_call(done, callback, argument)
which is a whole lot more straightforward. Memory footprint cost is trivial - one extra pointer in struct nameidata.
Basically, we add a new structure (struct delayed_call; poor man's closure) and pass a reference to that to ->get_link(); if anything needs to be done once we are done with the string returned by ->get_link(), just fill that structure (as above) and that's it. It will be evaluated by caller once it's through with the symlink body.
I'd put it in linux/fs.h for now, but it certainly belongs in something like linux/types.h; the current location is temporary. And I'm quite sure that we have other places where something of that sort is open-coded - timers, for one thing and probably quite a few other things.
I would really love to be able to say
set_delayed_call(done, kfree, p);
but as it is I had to keep a wrapper - void kfree_link(void *). The problem is, you can't assign void f(const void *) to void (*p)(void *) - mismatch of qualifiers in the arguments makes the latter not assignment-compatible with the former. If there's a clever trick allowing to sidestep that, I'd be very happy; I don't know one. Any ideas not starting with "use C11" (or, worse yet, "use such and such C++ misfeature with arseloads of RTL required in order to implement it") would be welcome...
BTW, why are we passing unsigned long to free_page()? We have
a bit under 700 callers; excluding the ones that have an explicit cast to unsigned long right in the argument of call leaves ~150, and the rest tend to contain a lot of pointer casts of unsigned long thing they are feeding to free_page() (IOW, they would be just as happy if they kept it as a pointer all along). Sure, that would mean __get_free_page() et.al. returning void *, but I don't see any problems with that either... Is that just for historical reasons, or is there anything more subtle I'm missing here?
Anyway, for now the patch below is strictly for review and (if one
is brave enough) testing. Comments would be very welcome.
drivers/staging/lustre/lustre/llite/symlink.c +9 -9
@@ -118,8 +118,14 @@ failed:return rc; } +static void ll_put_link (void *p) +{ +ptlrpc_req_finished (p); +} +static const char *ll_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) {struct ptlrpc_request *request =NULL ;int rc;
@@ -137,22 +143,16 @@ static const char *ll_get_link(struct dentry *dentry, }/* symname may contain a pointer to the request message buffer, -* we delay request releasing until ll_put_link then. +* we delay request releasing then. */ - *cookie = request; +set_delayed_call (done, ll_put_link, request);return symname; } -static void ll_put_link (struct inode *unused,void *cookie) -{ -ptlrpc_req_finished (cookie); -} -const struct inode_operations ll_fast_symlink_inode_operations = { .readlink = generic_readlink, .setattr = ll_setattr, .get_link = ll_get_link, - .put_link = ll_put_link, .getattr = ll_getattr, .permission = ll_inode_permission, .setxattr = ll_setxattr,
fs/9p/vfs_inode.c +5 -4
@@ -1226,11 +1226,12 @@ ino_t v9fs_qid2ino(struct p9_qid *qid)* v9fs_vfs_get_link - follow a symlink path * @dentry: dentry for symlink * @inode: inode for symlink -* @cookie: place to pass the data to put_link() +* @done: delayed call for when we are done with the return value */ static const char *v9fs_vfs_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) {struct v9fs_session_info *v9ses;struct p9_fid *fid;
@@ -1266,7 +1267,8 @@ static const char *v9fs_vfs_get_link(struct dentry *dentry,p9stat_free (st);kfree (st); -return *cookie = res; +set_delayed_call (done, kfree_link, res); +return res; }/**
@@ -1460,7 +1462,6 @@ static const struct inode_operations v9fs_file_inode_operations = {static const struct inode_operations v9fs_symlink_inode_operations = { .readlink = generic_readlink, .get_link = v9fs_vfs_get_link, - .put_link = kfree_put_link, .getattr = v9fs_vfs_getattr, .setattr = v9fs_vfs_setattr, };
fs/9p/vfs_inode_dotl.c +5 -4
@@ -902,12 +902,13 @@ error:* v9fs_vfs_get_link_dotl - follow a symlink path * @dentry: dentry for symlink * @inode: inode for symlink -* @cookie: place to pass the data to put_link() +* @done: destructor for return value */ static const char *v9fs_vfs_get_link_dotl (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) {struct p9_fid *fid;char *target;
@@ -924,7 +925,8 @@ v9fs_vfs_get_link_dotl(struct dentry *dentry, retval =p9_client_readlink (fid, &target);if (retval)return ERR_PTR (retval); -return *cookie = target; +set_delayed_call (done, kfree_link, target); +return target; }int v9fs_refresh_inode_dotl (struct p9_fid *fid,struct inode *inode)
@@ -991,7 +993,6 @@ const struct inode_operations v9fs_file_inode_operations_dotl = {const struct inode_operations v9fs_symlink_inode_operations_dotl = { .readlink = generic_readlink, .get_link = v9fs_vfs_get_link_dotl, - .put_link = kfree_put_link, .getattr = v9fs_vfs_getattr_dotl, .setattr = v9fs_vfs_setattr_dotl, .setxattr = generic_setxattr,
fs/affs/symlink.c +0 -1
@@ -72,6 +72,5 @@ const struct address_space_operations affs_symlink_aops = {const struct inode_operations affs_symlink_inode_operations = { .readlink = generic_readlink, .get_link = page_get_link, - .put_link = page_put_link, .setattr = affs_notify_change, };
fs/autofs4/symlink.c +2 -1
@@ -13,7 +13,8 @@#include "autofs_i.h" static const char *autofs4_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) {struct autofs_sb_info *sbi;struct autofs_info *ino;
fs/btrfs/inode.c +0 -1
@@ -10097,7 +10097,6 @@ static const struct inode_operations btrfs_special_inode_operations = {static const struct inode_operations btrfs_symlink_inode_operations = { .readlink = generic_readlink, .get_link = page_get_link, - .put_link = page_put_link, .getattr = btrfs_getattr, .setattr = btrfs_setattr, .permission = btrfs_permission,
fs/cifs/cifsfs.c +0 -1
@@ -901,7 +901,6 @@ const struct inode_operations cifs_file_inode_ops = {const struct inode_operations cifs_symlink_inode_ops = { .readlink = generic_readlink, .get_link = cifs_get_link, - .put_link = kfree_put_link, .permission = cifs_permission,/* BB add the following two eventually */ /* revalidate: cifs_revalidate,
fs/cifs/cifsfs.h +2 -1
@@ -120,7 +120,8 @@ extern struct vfsmount *cifs_dfs_d_automount(struct path *path);#endif /* Functions related to symlinks */ -extern const char *cifs_get_link (struct dentry *,struct inode *,void **); +extern const char *cifs_get_link (struct dentry *,struct inode *, +struct delayed_call *);extern int cifs_symlink (struct inode *inode,struct dentry *direntry,const char *symname);extern int cifs_removexattr (struct dentry *,const char *);
fs/cifs/link.c +4 -2
@@ -627,7 +627,8 @@ cifs_hl_exit: }const char * -cifs_get_link (struct dentry *direntry,struct inode *inode,void **cookie) +cifs_get_link (struct dentry *direntry,struct inode *inode, +struct delayed_call *done) {int rc = -ENOMEM ;unsigned int xid;
@@ -680,7 +681,8 @@ cifs_get_link(struct dentry *direntry, struct inode *inode, void **cookie)kfree (target_path);return ERR_PTR (rc); } -return *cookie = target_path; +set_delayed_call (done, kfree_link, target_path); +return target_path; }int
fs/coda/cnode.c +0 -1
@@ -19,7 +19,6 @@ static inline int coda_fideq(struct CodaFid *fid1, struct CodaFid *fid2)static const struct inode_operations coda_symlink_inode_operations = { .readlink = generic_readlink, .get_link = page_get_link, - .put_link = page_put_link, .setattr = coda_setattr, };
fs/configfs/symlink.c +7 -4
@@ -280,9 +280,11 @@ static int configfs_getlink(struct dentry *dentry, char * path) }static const char *configfs_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) {unsigned long page; +char *body;int error;if (!dentry)
@@ -292,9 +294,11 @@ static const char *configfs_get_link(struct dentry *dentry,if (!page)return ERR_PTR (-ENOMEM ); - error =configfs_getlink (dentry, (char *)page); + body = (char *)page; + error =configfs_getlink (dentry, body);if (!error) { -return *cookie = (void *)page; +set_delayed_call (done, free_page_link, body); +return body; }free_page (page);
@@ -304,7 +308,6 @@ static const char *configfs_get_link(struct dentry *dentry,const struct inode_operations configfs_symlink_inode_operations = { .get_link = configfs_get_link, .readlink = generic_readlink, - .put_link = free_page_put_link, .setattr = configfs_setattr, };
fs/ecryptfs/inode.c +4 -3
@@ -673,7 +673,8 @@ out: }static const char *ecryptfs_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) {size_t len;char *buf;
@@ -687,7 +688,8 @@ static const char *ecryptfs_get_link(struct dentry *dentry,fsstack_copy_attr_atime (d_inode (dentry),d_inode (ecryptfs_dentry_to_lower (dentry))); buf[len] ='\0' ; -return *cookie = buf; +set_delayed_call (done, kfree_link, buf); +return buf; }/**
@@ -1100,7 +1102,6 @@ out:const struct inode_operations ecryptfs_symlink_iops = { .readlink = generic_readlink, .get_link = ecryptfs_get_link, - .put_link = kfree_put_link, .permission = ecryptfs_permission, .setattr = ecryptfs_setattr, .getattr = ecryptfs_getattr_link,
fs/ext2/symlink.c +0 -1
@@ -23,7 +23,6 @@const struct inode_operations ext2_symlink_inode_operations = { .readlink = generic_readlink, .get_link = page_get_link, - .put_link = page_put_link, .setattr = ext2_setattr, #ifdef CONFIG_EXT2_FS_XATTR .setxattr = generic_setxattr,
fs/ext4/symlink.c +4 -4
@@ -24,7 +24,8 @@#ifdef CONFIG_EXT4_FS_ENCRYPTION static const char *ext4_encrypted_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) {struct page *cpage =NULL ;char *caddr, *paddr =NULL ;
@@ -80,7 +81,8 @@ static const char *ext4_encrypted_get_link(struct dentry *dentry, paddr[res] ='\0' ;if (cpage)page_cache_release (cpage); -return *cookie = paddr; +set_delayed_call (done, kfree_link, paddr); +return paddr; errout:if (cpage)page_cache_release (cpage);
@@ -91,7 +93,6 @@ errout:const struct inode_operations ext4_encrypted_symlink_inode_operations = { .readlink = generic_readlink, .get_link = ext4_encrypted_get_link, - .put_link = kfree_put_link, .setattr = ext4_setattr, .setxattr = generic_setxattr, .getxattr = generic_getxattr,
@@ -103,7 +104,6 @@ const struct inode_operations ext4_encrypted_symlink_inode_operations = {const struct inode_operations ext4_symlink_inode_operations = { .readlink = generic_readlink, .get_link = page_get_link, - .put_link = page_put_link, .setattr = ext4_setattr, .setxattr = generic_setxattr, .getxattr = generic_getxattr,
fs/f2fs/namei.c +9 -7
@@ -316,12 +316,14 @@ fail: }static const char *f2fs_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) { -const char *link =page_get_link (dentry, inode, cookie); +const char *link =page_get_link (dentry, inode, done);if (!IS_ERR (link) && !*link) {/* this is broken symlink case */ -page_put_link (NULL , *cookie); +do_delayed_call (done); + done->fn =NULL ; link =ERR_PTR (-ENOENT ); }return link;
@@ -926,7 +928,8 @@ static int f2fs_rename2(struct inode *old_dir, struct dentry *old_dentry,#ifdef CONFIG_F2FS_FS_ENCRYPTION static const char *f2fs_encrypted_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) {struct page *cpage =NULL ;char *caddr, *paddr =NULL ;
@@ -988,7 +991,8 @@ static const char *f2fs_encrypted_get_link(struct dentry *dentry, paddr[res] ='\0' ;page_cache_release (cpage); -return *cookie = paddr; +set_delayed_call (done, kfree_link, paddr); +return paddr; errout:kfree (cstr.name);f2fs_fname_crypto_free_buffer (&pstr);
@@ -999,7 +1003,6 @@ errout:const struct inode_operations f2fs_encrypted_symlink_inode_operations = { .readlink = generic_readlink, .get_link = f2fs_encrypted_get_link, - .put_link = kfree_put_link, .getattr = f2fs_getattr, .setattr = f2fs_setattr, .setxattr = generic_setxattr,
@@ -1035,7 +1038,6 @@ const struct inode_operations f2fs_dir_inode_operations = {const struct inode_operations f2fs_symlink_inode_operations = { .readlink = generic_readlink, .get_link = f2fs_get_link, - .put_link = page_put_link, .getattr = f2fs_getattr, .setattr = f2fs_setattr, #ifdef CONFIG_F2FS_FS_XATTR
fs/fuse/dir.c +3 -3
@@ -1366,7 +1366,8 @@ static int fuse_readdir(struct file *file, struct dir_context *ctx) }static const char *fuse_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) {struct fuse_conn *fc =get_fuse_conn (inode);FUSE_ARGS (args);
@@ -1392,7 +1393,7 @@ static const char *fuse_get_link(struct dentry *dentry, link =ERR_PTR (ret); }else { link[ret] ='\0' ; - *cookie = link; +set_delayed_call (done, free_page_link, link); }fuse_invalidate_atime (inode);return link;
@@ -1913,7 +1914,6 @@ static const struct inode_operations fuse_common_inode_operations = {static const struct inode_operations fuse_symlink_inode_operations = { .setattr = fuse_setattr, .get_link = fuse_get_link, - .put_link = free_page_put_link, .readlink = generic_readlink, .getattr = fuse_getattr, .setxattr = fuse_setxattr,
fs/gfs2/inode.c +4 -4
@@ -1715,7 +1715,7 @@ static int gfs2_rename2(struct inode *odir, struct dentry *odentry,* gfs2_get_link - Follow a symbolic link * @dentry: The dentry of the link * @inode: The inode of the link -* @cookie: place to store the information for ->put_link() +* @done: destructor for return value * * This can handle symlinks of any size. *
@@ -1723,7 +1723,8 @@ static int gfs2_rename2(struct inode *odir, struct dentry *odentry,*/ static const char *gfs2_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) {struct gfs2_inode *ip =GFS2_I (inode);struct gfs2_holder i_gh;
@@ -1764,7 +1765,7 @@ static const char *gfs2_get_link(struct dentry *dentry, out:gfs2_glock_dq_uninit (&i_gh);if (!IS_ERR (buf)) - *cookie = buf; +set_delayed_call (done, kfree_link, buf);return buf; }
@@ -2138,7 +2139,6 @@ const struct inode_operations gfs2_dir_iops = {const struct inode_operations gfs2_symlink_iops = { .readlink = generic_readlink, .get_link = gfs2_get_link, - .put_link = kfree_put_link, .permission = gfs2_permission, .setattr = gfs2_setattr, .getattr = gfs2_getattr,
fs/hostfs/hostfs_kern.c +6 -10
@@ -893,12 +893,13 @@ static const struct inode_operations hostfs_dir_iops = { };static const char *hostfs_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) {char *link;if (!dentry)return ERR_PTR (-ECHILD ); - link =__getname (); + link =kmalloc (PATH_MAX ,GFP_KERNEL );if (link) {char *path =dentry_name (dentry);int err = -ENOMEM ;
@@ -909,25 +910,20 @@ static const char *hostfs_get_link(struct dentry *dentry,__putname (path); }if (err <0 ) { -__putname (link); +kfree (link);return ERR_PTR (err); } }else {return ERR_PTR (-ENOMEM ); } -return *cookie = link; -} - -static void hostfs_put_link (struct inode *unused,void *cookie) -{ -__putname (cookie); +set_delayed_call (done, kfree_link, link); +return link; }static const struct inode_operations hostfs_link_iops = { .readlink = generic_readlink, .get_link = hostfs_get_link, - .put_link = hostfs_put_link, };static int hostfs_fill_sb_common (struct super_block *sb,void *d,int silent)
fs/jfs/symlink.c +0 -1
@@ -34,7 +34,6 @@ const struct inode_operations jfs_fast_symlink_inode_operations = {const struct inode_operations jfs_symlink_inode_operations = { .readlink = generic_readlink, .get_link = page_get_link, - .put_link = page_put_link, .setattr = jfs_setattr, .setxattr = jfs_setxattr, .getxattr = jfs_getxattr,
fs/kernfs/symlink.c +9 -6
@@ -113,22 +113,26 @@ static int kernfs_getlink(struct dentry *dentry, char *path) }static const char *kernfs_iop_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) { -int error = -ENOMEM ;unsigned long page; +char *body; +int error;if (!dentry)return ERR_PTR (-ECHILD ); page =get_zeroed_page (GFP_KERNEL );if (!page)return ERR_PTR (-ENOMEM ); - error =kernfs_getlink (dentry, (char *)page); + body = (char *)page; + error =kernfs_getlink (dentry, body);if (unlikely (error <0 )) { -free_page ((unsigned long )page); +free_page (page);return ERR_PTR (error); } -return *cookie = (char *)page; +set_delayed_call (done, free_page_link, body); +return body; }const struct inode_operations kernfs_symlink_iops = {
@@ -138,7 +142,6 @@ const struct inode_operations kernfs_symlink_iops = { .listxattr = kernfs_iop_listxattr, .readlink = generic_readlink, .get_link = kernfs_iop_get_link, - .put_link = free_page_put_link, .setattr = kernfs_iop_setattr, .getattr = kernfs_iop_getattr, .permission = kernfs_iop_permission,
fs/libfs.c +8 -7
@@ -1019,17 +1019,18 @@ int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync) }EXPORT_SYMBOL (noop_fsync); -void kfree_put_link (struct inode *unused,void *cookie) +/* Because kfree isn't assignment-compatible with void(void*) ;-/ */ +void kfree_link (void *p) { -kfree (cookie); +kfree (p); } -EXPORT_SYMBOL (kfree_put_link); +EXPORT_SYMBOL (kfree_link); -void free_page_put_link (struct inode *unused,void *cookie) +void free_page_link (void *p) { -free_page ((unsigned long ) cookie); +free_page ((unsigned long )p); } -EXPORT_SYMBOL (free_page_put_link); +EXPORT_SYMBOL (free_page_link);/* * nop .set_page_dirty method so that people can use .page_mkwrite on
@@ -1093,7 +1094,7 @@ simple_nosetlease(struct file *filp, long arg, struct file_lock **flp,EXPORT_SYMBOL (simple_nosetlease);const char *simple_get_link (struct dentry *dentry,struct inode *inode, -void **cookie) +struct delayed_call *done) {return inode->i_link; }
fs/minix/inode.c +0 -1
@@ -436,7 +436,6 @@ static const struct address_space_operations minix_aops = {static const struct inode_operations minix_symlink_inode_operations = { .readlink = generic_readlink, .get_link = page_get_link, - .put_link = page_put_link, .getattr = minix_getattr, };
fs/namei.c +26 -37
164 lines not on this page · raw message
fs/ncpfs/inode.c +0 -1
@@ -245,7 +245,6 @@ static void ncp_set_attr(struct inode *inode, struct ncp_entry_info *nwinfo)static const struct inode_operations ncp_symlink_inode_operations = { .readlink = generic_readlink, .get_link = page_get_link, - .put_link = page_put_link, .setattr = ncp_notify_change, };#endif
fs/nfs/symlink.c +3 -3
@@ -43,7 +43,8 @@ error: }static const char *nfs_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) {struct page *page;void *err;
@@ -68,7 +69,7 @@ static const char *nfs_get_link(struct dentry *dentry,if (IS_ERR (page))return ERR_CAST (page); } - *cookie = page; +set_delayed_call (done, page_put_link, page);return page_address (page); }
@@ -78,7 +79,6 @@ static const char *nfs_get_link(struct dentry *dentry,const struct inode_operations nfs_symlink_inode_operations = { .readlink = generic_readlink, .get_link = nfs_get_link, - .put_link = page_put_link, .getattr = nfs_getattr, .setattr = nfs_setattr, };
fs/nilfs2/namei.c +0 -1
@@ -570,7 +570,6 @@ const struct inode_operations nilfs_special_inode_operations = {const struct inode_operations nilfs_symlink_inode_operations = { .readlink = generic_readlink, .get_link = page_get_link, - .put_link = page_put_link, .permission = nilfs_permission, };
fs/ocfs2/symlink.c +0 -1
@@ -89,7 +89,6 @@ const struct address_space_operations ocfs2_fast_symlink_aops = {const struct inode_operations ocfs2_symlink_inode_operations = { .readlink = generic_readlink, .get_link = page_get_link, - .put_link = page_put_link, .getattr = ocfs2_getattr, .setattr = ocfs2_setattr, .setxattr = generic_setxattr,
fs/overlayfs/inode.c +3 -42
67 lines not on this page · raw message
fs/proc/base.c +5 -3
@@ -1565,7 +1565,8 @@ static int proc_exe_link(struct dentry *dentry, struct path *exe_path) }static const char *proc_pid_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) {struct path path;int error = -EACCES ;
@@ -1949,12 +1950,13 @@ struct map_files_info {*/ static const char *proc_map_files_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) {if (!capable (CAP_SYS_ADMIN ))return ERR_PTR (-EPERM ); -return proc_pid_get_link (dentry, inode,NULL ); +return proc_pid_get_link (dentry, inode, done); }/*
fs/proc/inode.c +8 -8
@@ -393,25 +393,25 @@ static const struct file_operations proc_reg_file_ops_no_compat = { };#endif +static void proc_put_link (void *p) +{ +unuse_pde (p); +} +static const char *proc_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) {struct proc_dir_entry *pde =PDE (inode);if (unlikely (!use_pde (pde)))return ERR_PTR (-EINVAL ); - *cookie = pde; +set_delayed_call (done, proc_put_link, pde);return pde->data; } -static void proc_put_link (struct inode *unused,void *p) -{ -unuse_pde (p); -} -const struct inode_operations proc_link_inode_operations = { .readlink = generic_readlink, .get_link = proc_get_link, - .put_link = proc_put_link, };struct inode *proc_get_inode (struct super_block *sb,struct proc_dir_entry *de)
fs/proc/namespaces.c +2 -1
@@ -31,7 +31,8 @@ static const struct proc_ns_operations *ns_entries[] = { };static const char *proc_ns_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) {const struct proc_ns_operations *ns_ops =PROC_I (inode)->ns_ops;struct task_struct *task;
fs/proc/self.c +4 -3
@@ -19,7 +19,8 @@ static int proc_self_readlink(struct dentry *dentry, char __user *buffer, }static const char *proc_self_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) {struct pid_namespace *ns = inode->i_sb->s_fs_info;pid_t tgid =task_tgid_nr_ns (current, ns);
@@ -32,13 +33,13 @@ static const char *proc_self_get_link(struct dentry *dentry,if (unlikely (!name))return dentry ?ERR_PTR (-ENOMEM ) :ERR_PTR (-ECHILD );sprintf (name,"%d" , tgid); -return *cookie = name; +set_delayed_call (done, kfree_link, name); +return name; }static const struct inode_operations proc_self_inode_operations = { .readlink = proc_self_readlink, .get_link = proc_self_get_link, - .put_link = kfree_put_link, };static unsigned self_inum;
fs/proc/thread_self.c +4 -3
@@ -20,7 +20,8 @@ static int proc_thread_self_readlink(struct dentry *dentry, char __user *buffer, }static const char *proc_thread_self_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) {struct pid_namespace *ns = inode->i_sb->s_fs_info;pid_t tgid =task_tgid_nr_ns (current, ns);
@@ -34,13 +35,13 @@ static const char *proc_thread_self_get_link(struct dentry *dentry,if (unlikely (!name))return dentry ?ERR_PTR (-ENOMEM ) :ERR_PTR (-ECHILD );sprintf (name,"%d/task/%d" , tgid, pid); -return *cookie = name; +set_delayed_call (done, kfree_link, name); +return name; }static const struct inode_operations proc_thread_self_inode_operations = { .readlink = proc_thread_self_readlink, .get_link = proc_thread_self_get_link, - .put_link = kfree_put_link, };static unsigned thread_self_inum;
fs/reiserfs/namei.c +0 -1
@@ -1666,7 +1666,6 @@ const struct inode_operations reiserfs_dir_inode_operations = {const struct inode_operations reiserfs_symlink_inode_operations = { .readlink = generic_readlink, .get_link = page_get_link, - .put_link = page_put_link, .setattr = reiserfs_setattr, .setxattr = reiserfs_setxattr, .getxattr = reiserfs_getxattr,
fs/squashfs/symlink.c +0 -1
@@ -120,7 +120,6 @@ const struct address_space_operations squashfs_symlink_aops = {const struct inode_operations squashfs_symlink_inode_ops = { .readlink = generic_readlink, .get_link = page_get_link, - .put_link = page_put_link, .getxattr = generic_getxattr, .listxattr = squashfs_listxattr };
fs/sysv/inode.c +0 -1
@@ -147,7 +147,6 @@ static inline void write3byte(struct sysv_sb_info *sbi,static const struct inode_operations sysv_symlink_inode_operations = { .readlink = generic_readlink, .get_link = page_get_link, - .put_link = page_put_link, .getattr = sysv_getattr, };
fs/xfs/xfs_iops.c +3 -3
@@ -417,7 +417,7 @@ STATIC const char *xfs_vn_get_link ( struct dentry *dentry, struct inode *inode, - void **cookie) + struct delayed_call *done) { char *link;int error = -ENOMEM ;
@@ -433,7 +433,8 @@ xfs_vn_get_link(if (unlikely (error)) goto out_kfree; -return *cookie = link; +set_delayed_call (done, kfree_link, link); +return link; out_kfree:kfree (link);
@@ -1177,7 +1178,6 @@ static const struct inode_operations xfs_dir_ci_inode_operations = {static const struct inode_operations xfs_symlink_inode_operations = { .readlink = generic_readlink, .get_link = xfs_vn_get_link, - .put_link = kfree_put_link, .getattr = xfs_vn_getattr, .setattr = xfs_vn_setattr, .setxattr = generic_setxattr,
include/linux/fs.h +29 -7
@@ -1635,14 +1635,34 @@ struct file_operations { u64); }; +struct delayed_call { +void (*fn)(void *); +void *arg; +}; + +#define DEFINE_DELAYED_CALL (name) struct delayed_call name = {NULL, NULL} + +/* I really wish we had closures with sane typechecking... */ +static inline void set_delayed_call (struct delayed_call *call, +void (*fn)(void *),void *arg) +{ + call->fn = fn; + call->arg = arg; +} + +static inline void do_delayed_call (struct delayed_call *call) +{ +if (call->fn) + call->fn (call->arg); +} +struct inode_operations {struct dentry * (*lookup) (struct inode *,struct dentry *,unsigned int ); -const char * (*get_link) (struct dentry *,struct inode *,void **); +const char * (*get_link) (struct dentry *,struct inode *,struct delayed_call *);int (*permission) (struct inode *,int );struct posix_acl * (*get_acl)(struct inode *,int );int (*readlink) (struct dentry *,char __user *,int ); -void (*put_link) (struct inode *,void *);int (*create) (struct inode *,struct dentry *,umode_t ,bool );int (*link) (struct dentry *,struct inode *,struct dentry *);
@@ -2744,14 +2764,15 @@ extern const struct file_operations generic_ro_fops;extern int readlink_copy (char __user *,int ,const char *);extern int page_readlink (struct dentry *,char __user *,int ); -extern const char *page_get_link (struct dentry *,struct inode *,void **); -extern void page_put_link (struct inode *,void *); +extern const char *page_get_link (struct dentry *,struct inode *, +struct delayed_call *); +extern void page_put_link (void *);extern int __page_symlink (struct inode *inode,const char *symname,int len,int nofs);extern int page_symlink (struct inode *inode,const char *symname,int len);extern const struct inode_operations page_symlink_inode_operations; -extern void kfree_put_link (struct inode *,void *); -extern void free_page_put_link (struct inode *,void *); +extern void kfree_link (void *); +extern void free_page_link (void *);extern int generic_readlink (struct dentry *,char __user *,int );extern void generic_fillattr (struct inode *,struct kstat *);int vfs_getattr_nosec (struct path *path,struct kstat *stat);
@@ -2762,7 +2783,8 @@ void __inode_sub_bytes(struct inode *inode, loff_t bytes);void inode_sub_bytes (struct inode *inode,loff_t bytes);loff_t inode_get_bytes (struct inode *inode);void inode_set_bytes (struct inode *inode,loff_t bytes); -const char *simple_get_link (struct dentry *,struct inode *,void **); +const char *simple_get_link (struct dentry *,struct inode *, +struct delayed_call *);extern const struct inode_operations simple_symlink_inode_operations;extern int iterate_dir (struct file *,struct dir_context *);
mm/shmem.c +9 -10
@@ -2496,8 +2496,15 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *sreturn 0 ; } +static void shmem_put_link (void *arg) +{ +mark_page_accessed (arg); +put_page (arg); +} +static const char *shmem_get_link (struct dentry *dentry, -struct inode *inode,void **cookie) +struct inode *inode, +struct delayed_call *done) {struct page *page =NULL ;int error;
@@ -2515,17 +2522,10 @@ static const char *shmem_get_link(struct dentry *dentry,return ERR_PTR (error);unlock_page (page); } - *cookie = page; +set_delayed_call (done, shmem_put_link, page);return page_address (page); } -static void shmem_put_link (struct inode *unused,void *cookie) -{ -struct page *page = cookie; -mark_page_accessed (page); -page_cache_release (page); -} -#ifdef CONFIG_TMPFS_XATTR /* * Superblocks without xattr inode operations may get some security.* xattr
@@ -2633,7 +2633,6 @@ static const struct inode_operations shmem_short_symlink_operations = {static const struct inode_operations shmem_symlink_inode_operations = { .readlink = generic_readlink, .get_link = shmem_get_link, - .put_link = shmem_put_link, #ifdef CONFIG_TMPFS_XATTR .setxattr = generic_setxattr, .getxattr = generic_getxattr,
Quoted 9 lines · Al Viro
I would really love to be able to say
set_delayed_call(done, kfree, p);but as it is I had to keep a wrapper - void
kfree_link(void *). The problem is, you can't assign voidf(const void *)to void (*p)(void *) - mismatch of qualifiers in the arguments makes the latter not assignment-compatible with the former. If there's a clever trick allowing to sidestep that, I'd be very happy; I don't know one. Any ideas not starting with "use C11" (or, worse yet, "use such and such C++ misfeature with arseloads of RTL required in order to implement it") would be welcome...
I _think_ this satisfies these very reasonable criteria. What you're looking for is presumably __attribute__((__transparent_union__)). At least this compiles without warnings at -Wall -Wextra and gives the expected disassembly, and the gcc docs mention transparent_union at least back to 4.0.4.
#include <stddef.h>
struct delayed_call {
void (*fn)(void *);
void *arg;
};
union delayed_call_fn {
void (*fn)(void *);
void (*kfree_like)(const void *);
} __attribute__((__transparent_union__));voidset_delayed_call(struct delayed_call *call, union delayed_call_fn u, void *arg)
{
call->fn = u.fn;
call->arg = arg;
}void some_cb(void *);
void kfree(const void *);
extern struct delayed_call done;
void test(void)
{
set_delayed_call(&done, some_cb, NULL);
set_delayed_call(&done, kfree, NULL);
}Rasmus
Al Viro
maintainerQuoted 11 lines · Rasmus Villemoes
union delayed_call_fn { void (*fn)(void *); void (*kfree_like)(const void *); } __attribute__((__transparent_union__));void
set_delayed_call(struct delayed_call *call, union delayed_call_fn u, void *arg){ call->fn = u.fn; call->arg = arg; }
Yecchhhh... If we are into that kind of gccisms, I'd rather use
__builtin_choose_expr/__builtin_types_compatible_p. At least that is used elsewhere in the kernel; __transparent_union__ kludge isn't. Sure, it means having set_delayed_call() a macro, but IMO it's less nasty that way...
FWIW, another possibility is to have
#define CLOSURE_CALLBACK(f,type) \
static inline void __closure_##f(void *p) {return f((type)p);}#define set_delayed_type(call, f, arg) \ sizeof(f(arg),0), \ __set_delayed_type(call, __closure_##f, (void *)arg)
That could be reused for timers with typechecking - we have a lot of timer callbacks that start with casting the argument (unsigned long, not void *, but that's not a big deal) to whatever it is that callback really wants, with setup_timer() callers explicitly casting that whatever the callback really wants to unsigned long. Which, of course, defeats the typechecking by both cc(1) and sparse(1)...
I still hope for better solution, though... Comments?
Al Viro
maintainerQuoted 4 lines · Al Viro
#define set_delayed_type(call, f, arg) \ sizeof(f(arg),0), \ __set_delayed_type(call, __closure_##f, (void *)arg)
Quoted 8 lines
That could be reused for timers with typechecking - we have a lot of timer callbacks that start with casting the argument (unsigned long, not void *, but that's not a big deal) to whatever it is that callback really wants, with
setup_timer()callers explicitly casting that whatever the callback really wants to unsigned long. Which, of course, defeats the typechecking by both cc(1) and sparse(1)...I still hope for better solution, though... Comments?
Hmm...
#define set_delayed_type(call, f, arg) \
(sizeof(f(arg),0), \
__set_delayed_type(call, ({ \
void _(void *__) {f((typeof(arg))(unsigned long)__);} \
_;}), (void *)arg))woult do nicely, but it's a gccism, and the one clang doesn't support ;-/ gcc support goes back at least to 4.1, not sure about the earlier branches (and not at all sure how flaky it was/is, obviously).
But this thing works for e.g. f being void(char) and arg being char, and AFAICS generates correct code - we end up with a stub like _.1765:
movsbl %dil, %edi
jmp f
and its address gets stored in call->fn, which should DTRT on call...
Quoted 17 lines · Al Viro
Quoted 4 lines · Al Viro
#define set_delayed_type(call, f, arg) \ sizeof(f(arg),0), \ __set_delayed_type(call, __closure_##f, (void *)arg)Quoted 8 lines
That could be reused for timers with typechecking - we have a lot of timer callbacks that start with casting the argument (unsigned long, not void *, but that's not a big deal) to whatever it is that callback really wants, with
setup_timer()callers explicitly casting that whatever the callback really wants to unsigned long. Which, of course, defeats the typechecking by both cc(1) and sparse(1)...I still hope for better solution, though... Comments?
Hmm...
Quoted 8 lines
#define
set_delayed_type(call, f, arg)\(sizeof(f(arg),0), \ __set_delayed_type(call, ({ \ void _(void *__) {f((typeof(arg))(unsigned long)__);} \ _;}), (void *)arg))woult do nicely, but it's a gccism, and the one clang doesn't support ;-/
Careful. While this may appear to work, I'm pretty sure it would break horribly when f is not the actual name of a function but a function pointer. Not that it won't compile, but it would presumably make gcc emit what they call a 'trampoline', a small piece of executable code located on the stack, allowing the stub to access the containing function's local variables (namely, f). I don't know if kernel stacks are even executable, but even then it's a bad idea, once the stack frame containing the trampoline is gone. All of this could easily happen down the line when someone sees a bunch of similar code and decides to factor that into a helper(), and then it works whenever gcc decides to inline the helper to both call sites and otherwise, as the gcc docs put it, "all hell breaks loose". IOWs, an accident waiting to happen.
One could probably ensure that the macro is always used with a compile/link-time constant by putting in some trick like
static void *link_time_constant_please = f;
but even then I wouldn't be completely sure that gcc would always emit a stub as simple as the one you showed.
Rasmus
Al Viro
maintainerQuoted 8 lines · Al Viro
BTW, why are we passing unsigned long to
free_page()? We have
a bit under 700 callers; excluding the ones that have an explicit cast to unsigned long right in the argument of call leaves ~150, and the rest tend to contain a lot of pointer casts of unsigned long thing they are feeding tofree_page()(IOW, they would be just as happy if they kept it as a pointer all along). Sure, that would mean__get_free_page()et.al. returning void *, but I don't see any problems with that either... Is that just for historical reasons, or is there anything more subtle I'm missing here?
The situation with free_pages() is even funnier - we have 313 call sites, and after converting it to void(void *, unsigned) 31 of them need casts to void *. Right now the mainline has 249 of those call sites with cast to unsigned long (or ulong, in several places). Then there's a bunch of places where we do __get_free_pages(), then use it a lot (all with casts to pointers), then pass to free_pages() - those would be just fine with storing it as void *, but even leaving those aside...
The current signature is contrary to actual use - nearly 80% of call sites are forced to cast a pointer to unsigned long, only to have it cast back to void * in free_pages() itself, we would obviously be better off if we'd switched to just passing the damn thing as a pointer. Especially since that 80% turn into 90% once you add the callers that could easily switch to storing the value eventually passed to free_pages() as a pointer.
And free_page() is basically the same story, only with twice as many call sites...
While we are at it: __get_free_pages() has 238 call sites. 193 of them immediately cast to pointer. And there's a bunch of places like this:
static inline void __tlb_alloc_page(struct mmu_gather *tlb)
{
unsigned long addr = __get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
if (addr) {
tlb->pages = (void *)addr;
tlb->max = PAGE_SIZE / sizeof(struct page *);
}
}where the cast is not immediate, but might as well had been. And conversion of free_pages() whittles it down even more. For __get_free_page() the situation is about the same, ditto for get_zeroed_page().
I realize that get_free_page() has been returning unsigned long since 0.01, but looking at 0.01... it might as well had been returning void * - wouldn't be more inconvenient. The kludge you had in get_pipe_inode() would've been a bit more obviously wrong, but that's about it ;-)
Seriously, though - what do you think about a flagday commit right after 4.5-rc1 switching all those guys to void *? For __get_user_pages(), __get_user_page(), get_zeroed_page() - return values, for free_pages(), free_page() - argument.
Hi Al,
thanks a lot for this. I particularly like that you renamed "follow_link" which didn't really describe what the function did any more.
Apart from the changelog comment in 4/11 which starts
"It was to needed for ..."
I can't fault anything.
Thanks,
NeilBrown