Dcache Fastwalk for 2.4.20
Subsystems (4)
PATCH 1/1 Dcache Fastwalk for 2.4.20
Hi Marcelo,
This patch is a backport of the work Al Viro and I did
in 2.5 to decrease cacheline bouncing during dcache lookup. This also removes path_init and replaces it with path_lookup (hence the changes in intermezzo and nfsd) as it is in 2.5.
Please consider this for inclusion in the next 2.4.2* release.
Thanks.
Hanna Linder
IBM Linux Technology Center
---------
fs/dcache.c +0 -0
@@ -702,13 +702,25 @@
struct dentry * d_lookup(struct dentry * parent, struct qstr * name) {
+ struct dentry *dentry = NULL;
+
+ spin_lock(&dcache_lock);
+ dentry = __d_lookup(parent,name);
+ if (dentry)
+ __dget_locked(dentry);
+ spin_unlock(&dcache_lock);
+ return dentry;
+}
+
+struct dentry * __d_lookup(struct dentry * parent, struct qstr * name) +{
+
unsigned int len = name->len; unsigned int hash = name->hash; const unsigned char *str = name->name; struct list_head *head = d_hash(parent,hash); struct list_head *tmp;
- spin_lock(&dcache_lock);
tmp = head->next;
for (;;) {
struct dentry * dentry = list_entry(tmp, struct dentry, d_hash);
@@ -728,12 +740,9 @@
if (memcmp(dentry->d_name.name, str, len))
continue;
}
- __dget_locked(dentry);
dentry->d_vfs_flags |= DCACHE_REFERENCED;
- spin_unlock(&dcache_lock);
return dentry;
}
- spin_unlock(&dcache_lock);
return NULL;
}fs/intermezzo/journal.c +1 -2
@@ -617,8 +617,7 @@CDEBUG (D_CACHE ,"looking up: %s\n" , path); -if (path_init (path,LOOKUP_PARENT , nd)) - error =path_walk (path, nd); + error =path_lookup (path,LOOKUP_PARENT , nd);if (error) {EXIT ;return error;
fs/intermezzo/presto.c +1 -2
@@ -53,8 +53,7 @@ENTRY ; err =0 ; -if (path_init (name, flags, nd)) - err =path_walk (name, nd); + err =path_lookup (name, flags, nd);return err;
}
fs/intermezzo/vfs.c +0 -0
@@ -702,8 +702,7 @@/* this looks up the parent */
// if (path_init(pathname, LOOKUP_FOLLOW | LOOKUP_POSITIVE, &nd))
- if (path_init(pathname, LOOKUP_PARENT, &nd))
- error = path_walk(pathname, &nd);
+ error = path_lookup(pathname, LOOKUP_PARENT, &nd);
if (error) {
EXIT;
goto exit;
@@ -855,12 +854,10 @@
struct nameidata nd, old_nd;
error = 0;
- if (path_init(from, LOOKUP_POSITIVE, &old_nd))
- error = path_walk(from, &old_nd);
+ error = path_lookup(from, LOOKUP_POSITIVE, &old_nd);
if (error)
goto exit;
- if (path_init(to, LOOKUP_PARENT, &nd))
- error = path_walk(to, &nd);
+ error = path_lookup(to, LOOKUP_PARENT, &nd);
if (error)
goto out;
error = -EXDEV;
@@ -1062,8 +1059,7 @@
if(IS_ERR(name))
return PTR_ERR(name);- if (path_init(name, LOOKUP_PARENT, &nd))
- error = path_walk(name, &nd);
+ error = path_lookup(name, LOOKUP_PARENT, &nd);
if (error)
goto exit;
error = -EISDIR;
@@ -1223,8 +1219,7 @@
goto exit_from;
}- if (path_init(to, LOOKUP_PARENT, &nd))
- error = path_walk(to, &nd);
+ error = path_lookup(to, LOOKUP_PARENT, &nd);
if (error) {
EXIT;
goto exit_to;
@@ -1381,8 +1376,7 @@
return error;
}- if (path_init(pathname, LOOKUP_PARENT, &nd))
- error = path_walk(pathname, &nd);
+ error = path_lookup(pathname, LOOKUP_PARENT, &nd);
if (error)
goto out_name;@@ -1527,8 +1521,7 @@
return PTR_ERR(name);
}- if (path_init(name, LOOKUP_PARENT, &nd))
- error = path_walk(name, &nd);
+ error = path_lookup(name, LOOKUP_PARENT, &nd);
if (error) {
EXIT;
goto exit;
@@ -1693,8 +1686,7 @@
if (IS_ERR(tmp))
return PTR_ERR(tmp);- if (path_init(tmp, LOOKUP_PARENT, &nd))
- error = path_walk(tmp, &nd);
+ error = path_lookup(tmp, LOOKUP_PARENT, &nd);
if (error)
goto out;
dentry = lookup_create(&nd, 0);@@ -1973,14 +1965,11 @@
ENTRY;
- if (path_init(oldname, LOOKUP_PARENT, &oldnd))
- error = path_walk(oldname, &oldnd);
-
+ error = path_lookup(oldname, LOOKUP_PARENT, &oldnd);
if (error)
goto exit;- if (path_init(newname, LOOKUP_PARENT, &newnd))
- error = path_walk(newname, &newnd);
+ error = path_lookup(newname, LOOKUP_PARENT, &newnd);
if (error)
goto exit1;fs/namei.c +0 -0
@@ -263,7 +263,7 @@
static struct dentry * cached_lookup(struct dentry * parent, struct qstr * name, int flags)
{
struct dentry * dentry = d_lookup(parent, name);
-
+
if (dentry && dentry->d_op && dentry->d_op->d_revalidate) {
if (!dentry->d_op->d_revalidate(dentry, flags) && !d_invalidate(dentry))
{
dput(dentry);
@@ -273,6 +273,61 @@
return dentry;
}+/*for fastwalking*/
+static inline void unlock_nd(struct nameidata *nd)
+{
+ struct vfsmount *mnt = nd->old_mnt;
+ struct dentry *dentry = nd->old_dentry;
+ mntget(nd->mnt);
+ dget_locked(nd->dentry);
+ nd->old_mnt = NULL;
+ nd->old_dentry = NULL;
+ spin_unlock(&dcache_lock);
+ dput(dentry);
+ mntput(mnt);
+}
+
+static inline void lock_nd(struct nameidata *nd)
+{
+ spin_lock(&dcache_lock);
+ nd->old_mnt = nd->mnt;
+ nd->old_dentry = nd->dentry;
+}
+
+/*
+ * Short-cut version of permission(), for calling by
+ * path_walk(), when dcache lock is held. Combines parts
+ * of permission() and vfs_permission(), and tests ONLY for
+ * MAY_EXEC permission.
+ *
+ * If appropriate, check DAC only. If not appropriate, or
+ * short-cut DAC fails, then call permission() to do more
+ * complete permission check.
+ */
+static inline int exec_permission_lite(struct inode *inode) +{
+ umode_t mode = inode->i_mode;
+
+ if ((inode->i_op && inode->i_op->permission))
+ return -EAGAIN;
+
+ if (current->fsuid == inode->i_uid)
+ mode >>= 6;
+ else if (in_group_p(inode->i_gid))
+ mode >>= 3;
+
+ if (mode & MAY_EXEC)
+ return 0;
+
+ if ((inode->i_mode & S_IXUGO) && capable(CAP_DAC_OVERRIDE))
+ return 0;
+
+ if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_READ_SEARCH))
+ return 0;
+
+ return -EACCES;
+}
+
/*
* This is called when everything else fails, and we actually have
* to go to the low-level filesystem to find out what we should do..
@@ -354,10 +409,10 @@
return -ELOOP; }
-static inline int __follow_up(struct vfsmount **mnt, struct dentry **base) +int follow_up(struct vfsmount **mnt, struct dentry **dentry)
{
struct vfsmount *parent;
- struct dentry *dentry;
+ struct dentry *mountpoint;
spin_lock(&dcache_lock);
parent=(*mnt)->mnt_parent;
if (parent == *mnt) {
@@ -365,18 +420,27 @@
return 0;
}
mntget(parent);
- dentry=dget((*mnt)->mnt_mountpoint);
+ mountpoint=dget((*mnt)->mnt_mountpoint);
spin_unlock(&dcache_lock);
- dput(*base);
- *base = dentry;
+ dput(*dentry);
+ *dentry = mountpoint;
mntput(*mnt);
*mnt = parent;
return 1;
}-int follow_up(struct vfsmount **mnt, struct dentry **dentry) +static int follow_mount(struct vfsmount **mnt, struct dentry **dentry) {
- return __follow_up(mnt, dentry);
+ int res = 0;
+ while (d_mountpoint(*dentry)) {
+ struct vfsmount *mounted = lookup_mnt(*mnt, *dentry);
+ if (!mounted)
+ break;
+ *mnt = mounted;
+ *dentry = mounted->mnt_root;
+ res = 1;
+ }
+ return res;
}
static inline int __follow_down(struct vfsmount **mnt, struct dentry **dentry) @@ -402,41 +466,83 @@
return __follow_down(mnt,dentry); }
-static inline void follow_dotdot(struct nameidata *nd)
+static inline void follow_dotdot(struct vfsmount **mnt, struct dentry **dentry)
{
while(1) {
struct vfsmount *parent;- struct dentry *dentry;
- read_lock(¤t->fs->lock);
- if (nd->dentry == current->fs->root &&
- nd->mnt == current->fs->rootmnt) {
- read_unlock(¤t->fs->lock);
+ if (*dentry == current->fs->root &&
+ *mnt == current->fs->rootmnt)
break;
- }
- read_unlock(¤t->fs->lock);
- spin_lock(&dcache_lock);
- if (nd->dentry != nd->mnt->mnt_root) {
- dentry = dget(nd->dentry->d_parent);
- spin_unlock(&dcache_lock);
- dput(nd->dentry);
- nd->dentry = dentry;
+ if (*dentry != (*mnt)->mnt_root) {
+ *dentry = (*dentry)->d_parent; break; }
- parent=nd->mnt->mnt_parent;
- if (parent == nd->mnt) {
- spin_unlock(&dcache_lock);
+ parent=(*mnt)->mnt_parent;
+ if (parent == *mnt)
break;
- }
- mntget(parent);
- dentry=dget(nd->mnt->mnt_mountpoint);
- spin_unlock(&dcache_lock);
- dput(nd->dentry);
- nd->dentry = dentry;
- mntput(nd->mnt);
- nd->mnt = parent;
+ *dentry=(*mnt)->mnt_mountpoint;
+ *mnt = parent; }
- while (d_mountpoint(nd->dentry) && __follow_down(&nd->mnt, &nd->dentry))
- ;
+ follow_mount(mnt, dentry);
+}
+
+struct path {
+ struct vfsmount *mnt;
+ struct dentry *dentry;
+};
+
+/*
+ * It's more convoluted than I'd like it to be, but... it's still fairly + * small and for now I'd prefer to have fast path as straight as possible. + * It _is_ time-critical.
+ */
+static int do_lookup(struct nameidata *nd, struct qstr *name,
+ struct path *path, struct path *cached_path,
+ int flags)
+{
+ struct vfsmount *mnt = nd->mnt;
+ struct dentry *dentry = __d_lookup(nd->dentry, name);
+
+ if (!dentry)
+ goto dcache_miss;
+ if (dentry->d_op && dentry->d_op->d_revalidate)
+ goto need_revalidate;
+done:
+ path->mnt = mnt;
+ path->dentry = dentry;
+ return 0;
+
+dcache_miss:
+ unlock_nd(nd);
+
+need_lookup:
+ dentry = real_lookup(nd->dentry, name, LOOKUP_CONTINUE);
+ if (IS_ERR(dentry))
+ goto fail;
+ mntget(mnt);
+relock:
+ dput(cached_path->dentry);
+ mntput(cached_path->mnt);
+ cached_path->mnt = mnt;
+ cached_path->dentry = dentry;
+ lock_nd(nd);
+ goto done;
+
+need_revalidate:
+ mntget(mnt);
+ dget_locked(dentry);
+ unlock_nd(nd);
+ if (dentry->d_op->d_revalidate(dentry, flags))
+ goto relock;
+ if (d_invalidate(dentry))
+ goto relock;
+ dput(dentry);
+ mntput(mnt);
+ goto need_lookup;
+
+fail:
+ lock_nd(nd);
+ return PTR_ERR(dentry);
}
/*
@@ -449,15 +555,15 @@
*/
int link_path_walk(const char * name, struct nameidata *nd) {
- struct dentry *dentry;
+ struct path next, pinned = {NULL, NULL};
struct inode *inode;
int err;
unsigned int lookup_flags = nd->flags;
-
+
while (*name=='/')
name++;
if (!*name)- goto return_reval;
+ goto return_base;
inode = nd->dentry->d_inode; if (current->link_count) @@ -469,8 +575,12 @@ struct qstr this; unsigned int c;
- err = permission(inode, MAY_EXEC);
- dentry = ERR_PTR(err);
+ err = exec_permission_lite(inode);
+ if (err == -EAGAIN) {
+ unlock_nd(nd);
+ err = permission(inode, MAY_EXEC);
+ lock_nd(nd);
+ }
if (err)
break;
@@ -504,7 +614,7 @@
case 2: if (this.name[1] != '.') break; - follow_dotdot(nd); + follow_dotdot(&nd->mnt, &nd->dentry); inode = nd->dentry->d_inode; /* fallthrough */ case 1: @@ -520,30 +630,30 @@ break; } /* This does the actual lookups.. */
- dentry = cached_lookup(nd->dentry, &this, LOOKUP_CONTINUE);
- if (!dentry) {
- dentry = real_lookup(nd->dentry, &this, LOOKUP_CONTINUE);
- err = PTR_ERR(dentry);
- if (IS_ERR(dentry))
- break;
- }
+ err = do_lookup(nd, &this, &next, &pinned, LOOKUP_CONTINUE);
+ if (err)
+ break; /* Check mountpoints.. */
- while (d_mountpoint(dentry) && __follow_down(&nd->mnt, &dentry))
- ;
+ follow_mount(&next.mnt, &next.dentry);
err = -ENOENT; - inode = dentry->d_inode; + inode = next.dentry->d_inode; if (!inode) - goto out_dput; + break; err = -ENOTDIR; if (!inode->i_op)
- goto out_dput;
+ break;
if (inode->i_op->follow_link) {- err = do_follow_link(dentry, nd);
- dput(dentry);
+ mntget(next.mnt);
+ dget_locked(next.dentry);
+ unlock_nd(nd);
+ err = do_follow_link(next.dentry, nd);
+ dput(next.dentry);
+ mntput(next.mnt);
if (err)
goto return_err;
+ lock_nd(nd);
err = -ENOENT;
inode = nd->dentry->d_inode;
if (!inode)
@@ -552,8 +662,8 @@
if (!inode->i_op)
break;
} else {
- dput(nd->dentry);
- nd->dentry = dentry;
+ nd->mnt = next.mnt;
+ nd->dentry = next.dentry;
}
err = -ENOTDIR;
if (!inode->i_op->lookup)
@@ -572,52 +682,47 @@
case 2:
if (this.name[1] != '.')
break;
- follow_dotdot(nd);
+ follow_dotdot(&nd->mnt, &nd->dentry);
inode = nd->dentry->d_inode;
/* fallthrough */
case 1:
- goto return_reval;
+ goto return_base;
}
if (nd->dentry->d_op && nd->dentry->d_op->d_hash) {
err = nd->dentry->d_op->d_hash(nd->dentry, &this);
if (err < 0)
break;
}- dentry = cached_lookup(nd->dentry, &this, 0);
- if (!dentry) {
- dentry = real_lookup(nd->dentry, &this, 0);
- err = PTR_ERR(dentry);
- if (IS_ERR(dentry))
- break;
- }
- while (d_mountpoint(dentry) && __follow_down(&nd->mnt, &dentry))
- ;
- inode = dentry->d_inode;
+ err = do_lookup(nd, &this, &next, &pinned, 0);
+ if (err)
+ break;
+ follow_mount(&next.mnt, &next.dentry);
+ inode = next.dentry->d_inode;
if ((lookup_flags & LOOKUP_FOLLOW)
&& inode && inode->i_op && inode->i_op->follow_link) {- err = do_follow_link(dentry, nd);
- dput(dentry);
+ mntget(next.mnt);
+ dget_locked(next.dentry);
+ unlock_nd(nd);
+ err = do_follow_link(next.dentry, nd);
+ dput(next.dentry);
+ mntput(next.mnt);
if (err)
goto return_err;
inode = nd->dentry->d_inode;
+ lock_nd(nd);
} else {
- dput(nd->dentry);
- nd->dentry = dentry;
+ nd->mnt = next.mnt;
+ nd->dentry = next.dentry;
}
err = -ENOENT;
if (!inode)
- goto no_inode;
+ break;
if (lookup_flags & LOOKUP_DIRECTORY) {
err = -ENOTDIR;
if (!inode->i_op || !inode->i_op->lookup)
break;
}
goto return_base;-no_inode:
- err = -ENOENT;
- if (lookup_flags & (LOOKUP_POSITIVE|LOOKUP_DIRECTORY))
- break;
- goto return_base;lookup_parent:
nd->last = this; nd->last_type = LAST_NORM; @@ -627,33 +732,24 @@ nd->last_type = LAST_DOT; else if (this.len == 2 && this.name[1] == '.') nd->last_type = LAST_DOTDOT;
-return_reval:
- /*
- * We bypassed the ordinary revalidation routines.
- * Check the cached dentry for staleness.
- */
- dentry = nd->dentry;
- if (dentry && dentry->d_op && dentry->d_op->d_revalidate) {
- err = -ESTALE;
- if (!dentry->d_op->d_revalidate(dentry, 0)) {
- d_invalidate(dentry);
- break;
- }
- }return_base:
+ unlock_nd(nd);
+ dput(pinned.dentry);
+ mntput(pinned.mnt); return 0; -out_dput: - dput(dentry); - break; } + unlock_nd(nd); path_release(nd); return_err: + dput(pinned.dentry); + mntput(pinned.mnt); return err; }
int path_walk(const char * name, struct nameidata *nd)
{
current->total_link_count = 0;
+ lock_nd(nd);
return link_path_walk(name, nd);
}@@ -738,28 +834,35 @@
return 1; }
-/* SMP-safe */
-int path_lookup(const char *path, unsigned flags, struct nameidata *nd) -{
- int error = 0;
- if (path_init(path, flags, nd))
- error = path_walk(path, nd);
- return error;
-}
-
-/* SMP-safe */
-int path_init(const char *name, unsigned int flags, struct nameidata *nd) +int path_lookup(const char *name, unsigned int flags, struct nameidata *nd)
{
nd->last_type = LAST_ROOT; /* if there are only slashes... */
nd->flags = flags;- if (*name=='/')
- return walk_init_root(name,nd);
- read_lock(¤t->fs->lock);
- nd->mnt = mntget(current->fs->pwdmnt);
- nd->dentry = dget(current->fs->pwd);
- read_unlock(¤t->fs->lock);
- return 1;
+ if (*name=='/') {
+ read_lock(¤t->fs->lock);
+ if (current->fs->altroot && !(nd->flags & LOOKUP_NOALT)) {
+ nd->mnt = mntget(current->fs->altrootmnt);
+ nd->dentry = dget(current->fs->altroot);
+ read_unlock(¤t->fs->lock);
+ if (__emul_lookup_dentry(name,nd))
+ return 0;
+ read_lock(¤t->fs->lock);
+ }
+ read_unlock(¤t->fs->lock);
+ spin_lock(&dcache_lock);
+ nd->mnt = current->fs->rootmnt;
+ nd->dentry = current->fs->root;
+ }
+ else{
+ spin_lock(&dcache_lock);
+ nd->mnt = current->fs->pwdmnt;
+ nd->dentry = current->fs->pwd;
+ }
+ nd->old_mnt = NULL;
+ nd->old_dentry = NULL;
+ current->total_link_count = 0;
+ return link_path_walk(name, nd);
}
/*
@@ -1964,6 +2067,7 @@
/* weird __emul_prefix() stuff did it */ goto out; } + lock_nd(nd); res = link_path_walk(link, nd); out: if (current->link_count || res || nd->last_type!=LAST_NORM)
fs/namespace.c +0 -0
@@ -23,14 +23,13 @@
struct vfsmount *do_kern_mount(const char *type, int flags, char *name, void *data); int do_remount_sb(struct super_block *sb, int flags, void * data); +extern int __init init_rootfs(void);
void kill_super(struct super_block *sb);
static struct list_head *mount_hashtable;
static int hash_mask, hash_bits;
static kmem_cache_t *mnt_cache;
-extern void init_rootfs(void);
-
static inline unsigned long hash(struct vfsmount *mnt, struct dentry *dentry)
{
unsigned long tmp = ((unsigned long) mnt / L1_CACHE_BYTES);
@@ -1023,15 +1022,9 @@
if (!mnt_cache)
panic("Cannot create vfsmount cache");- mempages >>= (16 - PAGE_SHIFT);
- mempages *= sizeof(struct list_head);
- for (order = 0; ((1UL << order) << PAGE_SHIFT) < mempages; order++)
- ;
-
- do {
- mount_hashtable = (struct list_head *)
- __get_free_pages(GFP_ATOMIC, order);
- } while (mount_hashtable == NULL && --order >= 0);
+ order = 0;
+ mount_hashtable = (struct list_head *)
+ __get_free_pages(GFP_ATOMIC, order);
if (!mount_hashtable)
panic("Failed to allocate mount hash table\n");fs/nfsd/export.c +0 -0
@@ -214,8 +214,7 @@
/* Look up the dentry */ err = 0; - if (path_init(nxp->ex_path, LOOKUP_POSITIVE, &nd)) - err = path_walk(nxp->ex_path, &nd); + err = path_lookup(nxp->ex_path, LOOKUP_POSITIVE, &nd); if (err) goto out_unlock;
@@ -411,8 +410,7 @@
err = -EPERM;
if (path) {
- if (path_init(path, LOOKUP_POSITIVE, &nd) &&
- path_walk(path, &nd)) {
+ if (path_lookup(path, LOOKUP_POSITIVE, &nd)) {
printk("nfsd: exp_rootfh path not found %s", path);
return err;
}include/linux/dcache.h +0 -0
@@ -219,6 +219,7 @@
/* appendix may either be NULL or be used for transname suffixes */ extern struct dentry * d_lookup(struct dentry *, struct qstr *); +extern struct dentry * __d_lookup(struct dentry *, struct qstr *);
/* validate "insecure" dentry pointer */
extern int d_validate(struct dentry *, struct dentry *);
include/linux/fs.h +0 -0
@@ -657,6 +657,8 @@
struct qstr last; unsigned int flags; int last_type;
+ struct dentry *old_dentry;
+ struct vfsmount *old_mnt;
};
#define DQUOT_USR_ENABLED 0x01 /* User diskquotas enabled */
@@ -1296,6 +1298,7 @@
* - require a directory * - ending slashes ok even for nonexistent files * - internal "there are more path compnents" flag
+ * - locked when lookup done with dcache_lock held
*/
#define LOOKUP_FOLLOW (1)
#define LOOKUP_DIRECTORY (2)
@@ -1303,6 +1306,7 @@
#define LOOKUP_POSITIVE (8)
#define LOOKUP_PARENT (16)
#define LOOKUP_NOALT (32)
+
/*
* Type of the last component on LOOKUP_PARENT
*/
@@ -1330,7 +1334,6 @@
extern loff_t default_llseek(struct file *file, loff_t offset, int origin);
extern int FASTCALL(__user_walk(const char *, unsigned, struct nameidata *)); -extern int FASTCALL(path_init(const char *, unsigned, struct nameidata *)); extern int FASTCALL(path_walk(const char *, struct nameidata *)); extern int FASTCALL(path_lookup(const char *, unsigned, struct nameidata *)); extern int FASTCALL(link_path_walk(const char *, struct nameidata *));
include/linux/fs_struct.h +0 -0
@@ -32,10 +32,12 @@
struct dentry *old_root;
struct vfsmount *old_rootmnt;
write_lock(&fs->lock);
+ spin_lock(&dcache_lock);
old_root = fs->root;
old_rootmnt = fs->rootmnt;
fs->rootmnt = mntget(mnt);
fs->root = dget(dentry);
+ spin_unlock(&dcache_lock);
write_unlock(&fs->lock);
if (old_root) {
dput(old_root);
@@ -55,10 +57,12 @@
struct dentry *old_pwd;
struct vfsmount *old_pwdmnt;
write_lock(&fs->lock);
+ spin_lock(&dcache_lock);
old_pwd = fs->pwd;
old_pwdmnt = fs->pwdmnt;
fs->pwdmnt = mntget(mnt);
fs->pwd = dget(dentry);
+ spin_unlock(&dcache_lock);
write_unlock(&fs->lock);
if (old_pwd) {
dput(old_pwd);kernel/ksyms.c +0 -0
@@ -146,8 +146,8 @@
EXPORT_SYMBOL(follow_up);EXPORT_SYMBOL(follow_down);EXPORT_SYMBOL(lookup_mnt);
-EXPORT_SYMBOL(path_init);EXPORT_SYMBOL(path_walk);
+EXPORT_SYMBOL(path_lookup);EXPORT_SYMBOL(path_release);EXPORT_SYMBOL(__user_walk);EXPORT_SYMBOL(lookup_one_len);
net/unix/af_unix.c +0 -0
@@ -590,9 +590,8 @@
int err = 0;
if (sunname->sun_path[0]) {- if (path_init(sunname->sun_path,
- LOOKUP_POSITIVE|LOOKUP_FOLLOW, &nd))
- err = path_walk(sunname->sun_path, &nd);
+ err = path_lookup(sunname->sun_path,
+ LOOKUP_POSITIVE|LOOKUP_FOLLOW, &nd); if (err) goto fail; err = permission(nd.dentry->d_inode,MAY_WRITE);
@@ -685,8 +684,7 @@
* Get the parent directory, calculate the hash for last
* component.
*/
- if (path_init(sunaddr->sun_path, LOOKUP_PARENT, &nd))
- err = path_walk(sunaddr->sun_path, &nd);
+ err = path_lookup(sunaddr->sun_path, LOOKUP_PARENT, &nd); if (err) goto out_mknod_parent; /*
Quoted 9 lines · On 2002.12.10 Hanna Linder wrote:
Hi Marcelo,
This patch is a backport of the work Al Viro and I did
in 2.5 to decrease cacheline bouncing during dcache lookup. This also removespath_initand replaces it withpath_lookup(hence the changes in intermezzo and nfsd) as it is in 2.5.
Please consider this for inclusion in the next 2.4.2* release.
Quoted 5 lines
Thanks.
Hanna Linder
IBM Linux Technology Center
Is you mailer wrapping the patch ?
Signature · 4 lines
J.A. Magallon <[email protected]> \ Software is like sex: werewolf.able.es \ It's better when it's free Mandrake Linux release 9.1 (Cooker) for i586 Linux 2.4.20-jam1 (gcc 3.2 (Mandrake Linux 9.1 3.2-4mdk))
Quoted 1 line · --On Wednesday, December 11, 2002 02:07:37 AM +0100 "J.A. Magallon"…
Is you mailer wrapping the patch ?
Hanging head low... I reloaded my mailer and forgot to change the default line wrapping size... So sorry. Thanks for your interest though. I will have a 2.4.21-pre1 version soon.
Hanna
------
fs/dcache.c +13 -4
@@ -702,13 +702,25 @@struct dentry *d_lookup (struct dentry * parent,struct qstr * name) { +struct dentry *dentry =NULL ; + +spin_lock (&dcache_lock); + dentry =__d_lookup (parent,name); +if (dentry) +__dget_locked (dentry); +spin_unlock (&dcache_lock); +return dentry; +} + +struct dentry *__d_lookup (struct dentry * parent,struct qstr * name) +{ +unsigned int len = name->len;unsigned int hash = name->hash;const unsigned char *str = name->name;struct list_head *head =d_hash (parent,hash);struct list_head *tmp; -spin_lock (&dcache_lock); tmp = head->next;for (;;) { struct dentry * dentry = list_entry(tmp, struct dentry, d_hash);
@@ -728,12 +740,9 @@if (memcmp (dentry->d_name.name, str, len))continue ; } -__dget_locked (dentry); dentry->d_vfs_flags |=DCACHE_REFERENCED ; -spin_unlock (&dcache_lock);return dentry; } -spin_unlock (&dcache_lock);return NULL ; }
fs/intermezzo/journal.c +1 -2
@@ -617,8 +617,7 @@CDEBUG (D_CACHE ,"looking up: %s\n" , path); -if (path_init (path,LOOKUP_PARENT , nd)) - error =path_walk (path, nd); + error =path_lookup (path,LOOKUP_PARENT , nd);if (error) {EXIT ;return error;
fs/intermezzo/presto.c +1 -2
@@ -53,8 +53,7 @@ENTRY ; err =0 ; -if (path_init (name, flags, nd)) - err =path_walk (name, nd); + err =path_lookup (name, flags, nd);return err; }
fs/intermezzo/vfs.c +10 -21
@@ -702,8 +702,7 @@/* this looks up the parent */ // if (path_init(pathname, LOOKUP_FOLLOW | LOOKUP_POSITIVE, &nd)) -if (path_init (pathname,LOOKUP_PARENT , &nd)) - error =path_walk (pathname, &nd); + error =path_lookup (pathname,LOOKUP_PARENT , &nd);if (error) {EXIT ; goto exit;
@@ -855,12 +854,10 @@struct nameidata nd, old_nd; error =0 ; -if (path_init (from,LOOKUP_POSITIVE , &old_nd)) - error =path_walk (from, &old_nd); + error =path_lookup (from,LOOKUP_POSITIVE , &old_nd);if (error) goto exit; -if (path_init (to,LOOKUP_PARENT , &nd)) - error =path_walk (to, &nd); + error =path_lookup (to,LOOKUP_PARENT , &nd);if (error) goto out; error = -EXDEV ;
@@ -1062,8 +1059,7 @@if (IS_ERR (name))return PTR_ERR (name); -if (path_init (name,LOOKUP_PARENT , &nd)) - error =path_walk (name, &nd); + error =path_lookup (name,LOOKUP_PARENT , &nd);if (error) goto exit; error = -EISDIR ;
@@ -1223,8 +1219,7 @@ goto exit_from; } -if (path_init (to,LOOKUP_PARENT , &nd)) - error =path_walk (to, &nd); + error =path_lookup (to,LOOKUP_PARENT , &nd);if (error) {EXIT ; goto exit_to;
@@ -1381,8 +1376,7 @@return error; } -if (path_init (pathname,LOOKUP_PARENT , &nd)) - error =path_walk (pathname, &nd); + error =path_lookup (pathname,LOOKUP_PARENT , &nd);if (error) goto out_name;
@@ -1527,8 +1521,7 @@return PTR_ERR (name); } -if (path_init (name,LOOKUP_PARENT , &nd)) - error =path_walk (name, &nd); + error =path_lookup (name,LOOKUP_PARENT , &nd);if (error) {EXIT ; goto exit;
@@ -1693,8 +1686,7 @@if (IS_ERR (tmp))return PTR_ERR (tmp); -if (path_init (tmp,LOOKUP_PARENT , &nd)) - error =path_walk (tmp, &nd); + error =path_lookup (tmp,LOOKUP_PARENT , &nd);if (error) goto out; dentry =lookup_create (&nd,0 );
@@ -1973,14 +1965,11 @@ENTRY ; -if (path_init (oldname,LOOKUP_PARENT , &oldnd)) - error =path_walk (oldname, &oldnd); - + error =path_lookup (oldname,LOOKUP_PARENT , &oldnd);if (error) goto exit; -if (path_init (newname,LOOKUP_PARENT , &newnd)) - error =path_walk (newname, &newnd); + error =path_lookup (newname,LOOKUP_PARENT , &newnd);if (error) goto exit1;
fs/namei.c +217 -113
486 lines not on this page · raw message
fs/namespace.c +4 -11
@@ -23,14 +23,13 @@struct vfsmount *do_kern_mount (const char *type,int flags,char *name,void *data);int do_remount_sb (struct super_block *sb,int flags,void * data); +extern int __init init_rootfs (void );void kill_super (struct super_block *sb);static struct list_head *mount_hashtable;static int hash_mask, hash_bits;static kmem_cache_t *mnt_cache; -extern void init_rootfs (void ); -static inline unsigned long hash (struct vfsmount *mnt,struct dentry *dentry) {unsigned long tmp = ((unsigned long ) mnt /L1_CACHE_BYTES );
@@ -1023,15 +1022,9 @@if (!mnt_cache)panic ("Cannot create vfsmount cache" ); - mempages >>= (16 -PAGE_SHIFT ); - mempages *=sizeof (struct list_head ); -for (order =0 ; ((1UL << order) <<PAGE_SHIFT ) < mempages; order++) - ; - -do { - mount_hashtable = (struct list_head *) -__get_free_pages (GFP_ATOMIC , order); - }while (mount_hashtable ==NULL && --order >=0 ); + order =0 ; + mount_hashtable = (struct list_head *) +__get_free_pages (GFP_ATOMIC , order);if (!mount_hashtable)panic ("Failed to allocate mount hash table\n" );
fs/nfsd/export.c +2 -4
@@ -214,8 +214,7 @@/* Look up the dentry */ err =0 ; -if (path_init (nxp->ex_path,LOOKUP_POSITIVE , &nd)) - err =path_walk (nxp->ex_path, &nd); + err =path_lookup (nxp->ex_path,LOOKUP_POSITIVE , &nd);if (err) goto out_unlock;
@@ -411,8 +410,7 @@ err = -EPERM ;if (path) { -if (path_init (path,LOOKUP_POSITIVE , &nd) && -path_walk (path, &nd)) { +if (path_lookup (path,LOOKUP_POSITIVE , &nd)) {printk ("nfsd: exp_rootfh path not found %s" , path);return err; }
include/linux/dcache.h +1 -0
@@ -219,6 +219,7 @@/* appendix may either be NULL or be used for transname suffixes */ extern struct dentry *d_lookup (struct dentry *,struct qstr *); +extern struct dentry *__d_lookup (struct dentry *,struct qstr *);/* validate "insecure" dentry pointer */ extern int d_validate (struct dentry *,struct dentry *);
include/linux/fs.h +4 -1
@@ -657,6 +657,8 @@struct qstr last;unsigned int flags;int last_type; +struct dentry *old_dentry; +struct vfsmount *old_mnt; };#define DQUOT_USR_ENABLED 0x01/* User diskquotas enabled */
@@ -1296,6 +1298,7 @@* - require a directory * - ending slashes ok even for nonexistent files * - internal "there are more path compnents" flag +* - locked when lookup done with dcache_lock held */ #define LOOKUP_FOLLOW (1)#define LOOKUP_DIRECTORY (2)
@@ -1303,6 +1306,7 @@#define LOOKUP_POSITIVE (8)#define LOOKUP_PARENT (16)#define LOOKUP_NOALT (32) +/* * Type of the last component on LOOKUP_PARENT */
@@ -1330,7 +1334,6 @@extern loff_t default_llseek (struct file *file,loff_t offset,int origin);extern int FASTCALL (__user_walk (const char *,unsigned ,struct nameidata *)); -extern int FASTCALL (path_init (const char *,unsigned ,struct nameidata *));extern int FASTCALL (path_walk (const char *,struct nameidata *));extern int FASTCALL (path_lookup (const char *,unsigned ,struct nameidata *));extern int FASTCALL (link_path_walk (const char *,struct nameidata *));
include/linux/fs_struct.h +4 -0
@@ -32,10 +32,12 @@struct dentry *old_root;struct vfsmount *old_rootmnt;write_lock (&fs->lock); +spin_lock (&dcache_lock); old_root = fs->root; old_rootmnt = fs->rootmnt; fs->rootmnt =mntget (mnt); fs->root =dget (dentry); +spin_unlock (&dcache_lock);write_unlock (&fs->lock);if (old_root) {dput (old_root);
@@ -55,10 +57,12 @@struct dentry *old_pwd;struct vfsmount *old_pwdmnt;write_lock (&fs->lock); +spin_lock (&dcache_lock); old_pwd = fs->pwd; old_pwdmnt = fs->pwdmnt; fs->pwdmnt =mntget (mnt); fs->pwd =dget (dentry); +spin_unlock (&dcache_lock);write_unlock (&fs->lock);if (old_pwd) {dput (old_pwd);
kernel/ksyms.c +1 -1
@@ -146,8 +146,8 @@EXPORT_SYMBOL (follow_up);EXPORT_SYMBOL (follow_down);EXPORT_SYMBOL (lookup_mnt); -EXPORT_SYMBOL (path_init);EXPORT_SYMBOL (path_walk); +EXPORT_SYMBOL (path_lookup);EXPORT_SYMBOL (path_release);EXPORT_SYMBOL (__user_walk);EXPORT_SYMBOL (lookup_one_len);
net/unix/af_unix.c +3 -5
@@ -590,9 +590,8 @@int err =0 ;if (sunname->sun_path[0 ]) { -if (path_init (sunname->sun_path, -LOOKUP_POSITIVE |LOOKUP_FOLLOW , &nd)) - err =path_walk (sunname->sun_path, &nd); + err =path_lookup (sunname->sun_path, +LOOKUP_POSITIVE |LOOKUP_FOLLOW , &nd);if (err) goto fail; err =permission (nd.dentry->d_inode,MAY_WRITE );
@@ -685,8 +684,7 @@* Get the parent directory, calculate the hash for last * component. */ -if (path_init (sunaddr->sun_path,LOOKUP_PARENT , &nd)) - err =path_walk (sunaddr->sun_path, &nd); + err =path_lookup (sunaddr->sun_path,LOOKUP_PARENT , &nd);if (err) goto out_mknod_parent;/*