make UML call dentry_open() with a valid vfsmount

PATCH In review Dave Hansen 2 participants 4 messages Sep 27, 2007 – Sep 28, 2007 User-mode Linux (UML)

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Dave Hansen

author

2007-09-27 22:09 UTC #0 lore raw

PATCH 1/1 make UML call dentry_open() with a valid vfsmount

I'm trying to enforce the convention that you may not call dentry_open() with a NULL vfsmount. This is so that the r/o bind mount patches can consistenty acquire write access to the mounts there.

This patch fixes up UML's HPPFS to track both the vfsmount and the dentry for its files. Compile, but not runtime tested.

---

 lxc-dave/fs/hppfs/hppfs_kern.c |   31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff -puN fs/open.c~remove-UML-callers-of-dentry_open-with-null-mnt fs/open.c

fs/hppfs/hppfs_kern.c renamed from fs/hppfs/hppfs_kern.c~remove-UML-callers-of-dentry_open-with-null-mnt +17 ~~-14~~

diff -puN fs/hppfs/hppfs_kern.c~remove-UML-callers-of-dentry_open-with-null-mnt fs/hppfs/hppfs_kern.c
@@ -32,7 +32,7 @@ struct hppfs_private {
 };
 
 struct hppfs_inode_info {
-        struct dentry *proc_dentry;
+	struct path proc_path;
 	struct inode vfs_inode;
 };

@@ -139,10 +139,10 @@ static void hppfs_read_inode(struct inod
 {
 	struct inode *proc_ino;
 
-	if(HPPFS_I(ino)->proc_dentry == NULL)
+	if (HPPFS_I(ino)->proc_path.dentry == NULL)
 		return;
 
-	proc_ino = HPPFS_I(ino)->proc_dentry->d_inode;
+	proc_ino = HPPFS_I(ino)->proc_path.dentry->d_inode;
 	ino->i_uid = proc_ino->i_uid;
 	ino->i_gid = proc_ino->i_gid;
 	ino->i_atime = proc_ino->i_atime;

@@ -169,7 +169,7 @@ static struct dentry *hppfs_lookup(struc
 		return(ERR_PTR(-ENOENT));
 
 	err = -ENOMEM;
-	parent = HPPFS_I(ino)->proc_dentry;
+	parent = HPPFS_I(ino)->proc_path.dentry;
 	mutex_lock(&parent->d_inode->i_mutex);
 	proc_dentry = d_lookup(parent, &dentry->d_name);
 	if(proc_dentry == NULL){

@@ -455,7 +455,7 @@ static int file_mode(int fmode)
 static int hppfs_open(struct inode *inode, struct file *file)
 {
 	struct hppfs_private *data;
-	struct dentry *proc_dentry;
+	struct path *proc_path;
 	char *host_file;
 	int err, fd, type, filter;

@@ -468,10 +468,11 @@ static int hppfs_open(struct inode *inod
 	if(host_file == NULL)
 		goto out_free2;
 
-	proc_dentry = HPPFS_I(inode)->proc_dentry;
+	proc_path = &HPPFS_I(inode)->proc_path;
 
 	/* XXX This isn't closed anywhere */
-	data->proc_file = dentry_open(dget(proc_dentry), NULL,
+	data->proc_file = dentry_open(dget(proc_path->dentry),
+				      mntget(proc_path->mnt),
 				      file_mode(file->f_mode));
 	err = PTR_ERR(data->proc_file);
 	if(IS_ERR(data->proc_file))

@@ -516,7 +517,7 @@ static int hppfs_open(struct inode *inod
 static int hppfs_dir_open(struct inode *inode, struct file *file)
 {
 	struct hppfs_private *data;
-	struct dentry *proc_dentry;
+	struct path *proc_path;
 	int err;
 
 	err = -ENOMEM;

@@ -524,8 +525,9 @@ static int hppfs_dir_open(struct inode *
 	if(data == NULL)
 		goto out;
 
-	proc_dentry = HPPFS_I(inode)->proc_dentry;
-	data->proc_file = dentry_open(dget(proc_dentry), NULL,
+	proc_path = &HPPFS_I(inode)->proc_path;
+	data->proc_file = dentry_open(dget(proc_path->dentry),
+				      mntget(proc_path->mnt),
 				      file_mode(file->f_mode));
 	err = PTR_ERR(data->proc_file);
 	if(IS_ERR(data->proc_file))

@@ -634,7 +636,8 @@ static struct inode *hppfs_alloc_inode(s
 	if(hi == NULL)
 		return(NULL);
 
-	*hi = ((struct hppfs_inode_info) { .proc_dentry	= NULL });
+	hi->proc_path.dentry = NULL;
+	hi->proc_path.mnt = NULL;
 	inode_init_once(&hi->vfs_inode);
 	return(&hi->vfs_inode);
 }

@@ -663,7 +666,7 @@ static int hppfs_readlink(struct dentry 
 	struct dentry *proc_dentry;
 	int ret;
 
-	proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
+	proc_dentry = HPPFS_I(dentry->d_inode)->proc_path.dentry;
 	proc_file = dentry_open(dget(proc_dentry), NULL, O_RDONLY);
 	if (IS_ERR(proc_file))
 		return PTR_ERR(proc_file);

@@ -681,7 +684,7 @@ static void* hppfs_follow_link(struct de
 	struct dentry *proc_dentry;
 	void *ret;
 
-	proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
+	proc_dentry = HPPFS_I(dentry->d_inode)->proc_path.dentry;
 	proc_file = dentry_open(dget(proc_dentry), NULL, O_RDONLY);
 	if (IS_ERR(proc_file))
 		return proc_file;

@@ -717,7 +720,7 @@ static int init_inode(struct inode *inod
 		inode->i_fop = &hppfs_file_fops;
 	}
 
-	HPPFS_I(inode)->proc_dentry = dentry;
+	HPPFS_I(inode)->proc_path.dentry = dentry;
 
 	return(0);
 }

diff -puN fs/Kconfig~remove-UML-callers-of-dentry_open-with-null-mnt fs/Kconfig
diff -puN fs/Makefile~remove-UML-callers-of-dentry_open-with-null-mnt fs/Makefile
diff -puN arch/um/Kconfig~remove-UML-callers-of-dentry_open-with-null-mnt arch/um/Kconfig diff -puN include/linux/namei.h~remove-UML-callers-of-dentry_open-with-null-mnt include/linux/namei.h diff -puN arch/um/os-Linux/time.c~remove-UML-callers-of-dentry_open-with-null-mnt arch/um/os-Linux/time.c diff -puN fs/hppfs/Makefile~remove-UML-callers-of-dentry_open-with-null-mnt fs/hppfs/Makefile diff -puN MAINTAINERS~remove-UML-callers-of-dentry_open-with-null-mnt MAINTAINERS
_

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Jeff Dike

2007-09-28 15:03 UTC #1 lore raw

Quoted 9 lines · Dave Hansen

I'm trying to enforce the convention that you may not call dentry_open() with a NULL vfsmount. This is so that the r/o bind mount patches can consistenty acquire write access to the mounts there.
This patch fixes up UML's HPPFS to track both the vfsmount and the dentry for its files. Compile, but not runtime tested.

Can I get a Signed-off-by:?

Jeff

Signature · 10 lines

Work email - jdike at linux dot intel dot com

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Dave Hansen

author

2007-09-28 16:02 UTC #2 lore raw

Quoted 7 lines · Jeff Dike

Quoted 6 lines · Dave Hansen
I'm trying to enforce the convention that you may not call dentry_open() with a NULL vfsmount. This is so that the r/o bind mount patches can consistenty acquire write access to the mounts there.

Quoted 5 lines

Quoted 3 lines
This patch fixes up UML's HPPFS to track both the vfsmount and the dentry for its files. Compile, but not runtime tested.
Can I get a Signed-off-by:?

I'm trying to enforce the convention that you may not call dentry_open() with a NULL vfsmount. This is so that the r/o bind mount patches can consistenty acquire write access to the mounts there.

This patch fixes up UML's HPPFS to track both the vfsmount and the dentry for its files. Compile, but not runtime tested.

This also fixes a potential oops with the r/o bind mount patches caused by passing a NULL mnt into dentry_open(). After you've had a chance to verify that this works, could you send it up to -mm?

One more thing... have you had any problems getting arch/um/os-Linux/time.c to compile because of a lack of tv_to_nsec()?

Signed-off-by Dave Hansen <[email protected]>

---

 lxc-dave/fs/hppfs/hppfs_kern.c |   45 +++++++++++++++++++++++------------------
 1 file changed, 26 insertions(+), 19 deletions(-)

fs/hppfs/hppfs_kern.c renamed from fs/hppfs/hppfs_kern.c~remove-UML-callers-of-dentry_open-with-null-mnt +26 ~~-19~~

diff -puN fs/hppfs/hppfs_kern.c~remove-UML-callers-of-dentry_open-with-null-mnt fs/hppfs/hppfs_kern.c
@@ -17,7 +17,8 @@
 #include <asm/fcntl.h>
 #include "os.h"
 
-static int init_inode(struct inode *inode, struct dentry *dentry);
+static int init_inode(struct inode *inode, struct dentry *dentry,
+		struct vfsmount *mnt);
 
 struct hppfs_data {
 	struct list_head list;

@@ -32,7 +33,7 @@ struct hppfs_private {
 };
 
 struct hppfs_inode_info {
-        struct dentry *proc_dentry;
+	struct path proc_path;
 	struct inode vfs_inode;
 };

@@ -139,10 +140,10 @@ static void hppfs_read_inode(struct inod
 {
 	struct inode *proc_ino;
 
-	if(HPPFS_I(ino)->proc_dentry == NULL)
+	if (HPPFS_I(ino)->proc_path.dentry == NULL)
 		return;
 
-	proc_ino = HPPFS_I(ino)->proc_dentry->d_inode;
+	proc_ino = HPPFS_I(ino)->proc_path.dentry->d_inode;
 	ino->i_uid = proc_ino->i_uid;
 	ino->i_gid = proc_ino->i_gid;
 	ino->i_atime = proc_ino->i_atime;

@@ -169,7 +170,7 @@ static struct dentry *hppfs_lookup(struc
 		return(ERR_PTR(-ENOENT));
 
 	err = -ENOMEM;
-	parent = HPPFS_I(ino)->proc_dentry;
+	parent = HPPFS_I(ino)->proc_path.dentry;
 	mutex_lock(&parent->d_inode->i_mutex);
 	proc_dentry = d_lookup(parent, &dentry->d_name);
 	if(proc_dentry == NULL){

@@ -194,7 +195,7 @@ static struct dentry *hppfs_lookup(struc
 	if(inode == NULL)
 		goto out_dput;
 
-	err = init_inode(inode, proc_dentry);
+	err = init_inode(inode, proc_dentry, nd->mnt);
 	if(err)
 		goto out_put;

@@ -455,7 +456,7 @@ static int file_mode(int fmode)
 static int hppfs_open(struct inode *inode, struct file *file)
 {
 	struct hppfs_private *data;
-	struct dentry *proc_dentry;
+	struct path *proc_path;
 	char *host_file;
 	int err, fd, type, filter;

@@ -468,10 +469,11 @@ static int hppfs_open(struct inode *inod
 	if(host_file == NULL)
 		goto out_free2;
 
-	proc_dentry = HPPFS_I(inode)->proc_dentry;
+	proc_path = &HPPFS_I(inode)->proc_path;
 
 	/* XXX This isn't closed anywhere */
-	data->proc_file = dentry_open(dget(proc_dentry), NULL,
+	data->proc_file = dentry_open(dget(proc_path->dentry),
+				      mntget(proc_path->mnt),
 				      file_mode(file->f_mode));
 	err = PTR_ERR(data->proc_file);
 	if(IS_ERR(data->proc_file))

@@ -516,7 +518,7 @@ static int hppfs_open(struct inode *inod
 static int hppfs_dir_open(struct inode *inode, struct file *file)
 {
 	struct hppfs_private *data;
-	struct dentry *proc_dentry;
+	struct path *proc_path;
 	int err;
 
 	err = -ENOMEM;

@@ -524,8 +526,9 @@ static int hppfs_dir_open(struct inode *
 	if(data == NULL)
 		goto out;
 
-	proc_dentry = HPPFS_I(inode)->proc_dentry;
-	data->proc_file = dentry_open(dget(proc_dentry), NULL,
+	proc_path = &HPPFS_I(inode)->proc_path;
+	data->proc_file = dentry_open(dget(proc_path->dentry),
+				      mntget(proc_path->mnt),
 				      file_mode(file->f_mode));
 	err = PTR_ERR(data->proc_file);
 	if(IS_ERR(data->proc_file))

@@ -634,7 +637,8 @@ static struct inode *hppfs_alloc_inode(s
 	if(hi == NULL)
 		return(NULL);
 
-	*hi = ((struct hppfs_inode_info) { .proc_dentry	= NULL });
+	hi->proc_path.dentry = NULL;
+	hi->proc_path.mnt = NULL;
 	inode_init_once(&hi->vfs_inode);
 	return(&hi->vfs_inode);
 }

@@ -663,7 +667,7 @@ static int hppfs_readlink(struct dentry 
 	struct dentry *proc_dentry;
 	int ret;
 
-	proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
+	proc_dentry = HPPFS_I(dentry->d_inode)->proc_path.dentry;
 	proc_file = dentry_open(dget(proc_dentry), NULL, O_RDONLY);
 	if (IS_ERR(proc_file))
 		return PTR_ERR(proc_file);

@@ -681,7 +685,7 @@ static void* hppfs_follow_link(struct de
 	struct dentry *proc_dentry;
 	void *ret;
 
-	proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
+	proc_dentry = HPPFS_I(dentry->d_inode)->proc_path.dentry;
 	proc_file = dentry_open(dget(proc_dentry), NULL, O_RDONLY);
 	if (IS_ERR(proc_file))
 		return proc_file;

@@ -702,7 +706,8 @@ static const struct inode_operations hpp
 	.follow_link	= hppfs_follow_link,
 };
 
-static int init_inode(struct inode *inode, struct dentry *dentry)
+static int init_inode(struct inode *inode, struct dentry *dentry,
+			struct vfsmount *mnt)
 {
 	if(S_ISDIR(dentry->d_inode->i_mode)){
 		inode->i_op = &hppfs_dir_iops;

@@ -717,7 +722,8 @@ static int init_inode(struct inode *inod
 		inode->i_fop = &hppfs_file_fops;
 	}
 
-	HPPFS_I(inode)->proc_dentry = dentry;
+	HPPFS_I(inode)->proc_path.dentry = dentry;
+	HPPFS_I(inode)->proc_path.mnt = mnt;
 
 	return(0);
 }

@@ -727,6 +733,7 @@ static int hppfs_fill_super(struct super
 	struct inode *root_inode;
 	struct file_system_type *procfs;
 	struct super_block *proc_sb;
+	struct vfsmount *mnt = d;
 	int err;
 
 	err = -ENOENT;

@@ -749,7 +756,7 @@ static int hppfs_fill_super(struct super
 	if(root_inode == NULL)
 		goto out;
 
-	err = init_inode(root_inode, proc_sb->s_root);
+	err = init_inode(root_inode, proc_sb->s_root, mnt);
 	if(err)
 		goto out_put;

@@ -772,7 +779,7 @@ static int hppfs_read_super(struct file_
 			    int flags, const char *dev_name,
 			    void *data, struct vfsmount *mnt)
 {
-	return get_sb_nodev(type, flags, data, hppfs_fill_super, mnt);
+	return get_sb_nodev(type, flags, mnt, hppfs_fill_super, mnt);
 }
 
 static struct file_system_type hppfs_type = {

-- Dave

Jeff Dike

2007-09-28 16:47 UTC #3 lore raw

Quoted 2 lines · Dave Hansen

One more thing... have you had any problems getting arch/um/os-Linux/time.c to compile because of a lack of tv_to_nsec()?

That should be fixed in current -mm.

Jeff

Signature · 10 lines

Work email - jdike at linux dot intel dot com

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