[patch 00/10] vfs: add helpers to check r/o bind mounts v3

[patch 00/10] vfs: add helpers to check r/o bind mounts v3

[Miklos Szeredi]

Resend of the path_* API patches.  This is against the VFS cleanup
patches posted recently.

Description is in the first patch header.

Changes from the previous submission:

 - rename() API is made more symmetric
 - all impacted vfs_* functions are made static

Comments (not just Al's) are welcome ;)

Thanks,
Miklos

[patch 01/10] vfs: add path_create() and path_mknod()

[Miklos Szeredi]

[-- Attachment #1: path_create.patch --]
[-- Type: text/plain, Size: 13263 bytes --]

From: Miklos Szeredi <mszeredi@suse.cz>

R/O bind mounts require operations which modify the filesystem to be
wrapped in mnt_want_write()/mnt_drop_write().  Create helpers which do
this, so callers won't need to bother, and more importantly, cannot
forget!  Call these path_*, analogous to vfs_*.  Since there are no
callers of vfs_* left, make them static.

Overall this patchset is just 23 lines in the red, but at the same
time it fixes several places in nfsd and the whole of ecryptfs, where
the mnt_want_write/drop_write() calls were missing.

It will also help with merging certain security modules, which need to
know the path within the namespace, and not just within the
filesystem.  These helpers will allow the security hooks to be in a
common place, and need not be repeated in all callers.

Note, that the mnt_want_write/drop_write() bracketing provided by the
path_* functions strictly necessary in all cases, since the caller may
do it's own bracketing to span multiple VFS calls.  However, this does
not make the checks in path_* incorrect, just unnecessary.

The advantages of the path_* API are:

  - it's consistent

  - it provides some (not all) guarantees, i.e. it's easier to prove
    that all callers play by the rules

  - for the syscall case it has zero cost

  - for all the other cases it has either zero, or minimal cost

It does require the caller to have a vfsmount available, but it's hard
to imagine that the caller does not have it:

  - most userspace calls do have it, as they are either operating on a
    path or a file descriptor.  There are some exceptions like sync(2)
    and ustat(2), the latter not being a very exemplary interface, and
    neither of them being relevant to this discussion.

  - all kernel callers (nfs export, stacking) should have it, as they
    need it for open() anyway

And even if some theoretical caller didn't have the vfsmount, it still
should be easy to allocate one, providing a clean way to do the r/o
bracketing, and not requiring another mechanism to be exported that
provides the same functionality on the superblock.


This patch:

Introduce path_create() and path_mknod().  Make vfs_create() and
vfs_mknod() static.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
---
 fs/ecryptfs/inode.c |   33 ++++++++++------------
 fs/namei.c          |   75 +++++++++++++++++++++++++++-------------------------
 fs/nfsd/vfs.c       |   19 +++++++++----
 include/linux/fs.h  |    4 +-
 ipc/mqueue.c        |    6 +++-
 net/unix/af_unix.c  |    6 ----
 6 files changed, 76 insertions(+), 67 deletions(-)

Index: linux-2.6/fs/namei.c
===================================================================
--- linux-2.6.orig/fs/namei.c	2008-05-05 11:29:27.000000000 +0200
+++ linux-2.6/fs/namei.c	2008-05-05 11:29:29.000000000 +0200
@@ -1579,7 +1579,7 @@ void unlock_rename(struct dentry *p1, st
 	}
 }
 
-int vfs_create(struct inode *dir, struct dentry *dentry, int mode,
+static int vfs_create(struct inode *dir, struct dentry *dentry, int mode,
 		struct nameidata *nd)
 {
 	int error = may_create(dir, dentry, nd);
@@ -1601,6 +1601,20 @@ int vfs_create(struct inode *dir, struct
 	return error;
 }
 
+int path_create(struct path *dir_path, struct dentry *dentry, int mode,
+		struct nameidata *nd)
+{
+	int error = mnt_want_write(dir_path->mnt);
+
+	if (!error) {
+		error = vfs_create(dir_path->dentry->d_inode, dentry, mode, nd);
+		mnt_drop_write(dir_path->mnt);
+	}
+
+	return error;
+}
+EXPORT_SYMBOL(path_create);
+
 int may_open(struct nameidata *nd, int acc_mode, int flag)
 {
 	struct dentry *dentry = nd->path.dentry;
@@ -2017,7 +2031,7 @@ fail:
 }
 EXPORT_SYMBOL_GPL(lookup_create);
 
-int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
+static int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 {
 	int error = may_create(dir, dentry, NULL);
 
@@ -2045,22 +2059,19 @@ int vfs_mknod(struct inode *dir, struct 
 	return error;
 }
 
-static int may_mknod(mode_t mode)
+int path_mknod(struct path *dir_path, struct dentry *dentry, int mode,
+	       dev_t dev)
 {
-	switch (mode & S_IFMT) {
-	case S_IFREG:
-	case S_IFCHR:
-	case S_IFBLK:
-	case S_IFIFO:
-	case S_IFSOCK:
-	case 0: /* zero mode translates to S_IFREG */
-		return 0;
-	case S_IFDIR:
-		return -EPERM;
-	default:
-		return -EINVAL;
+	int error = mnt_want_write(dir_path->mnt);
+
+	if (!error) {
+		error = vfs_mknod(dir_path->dentry->d_inode, dentry, mode, dev);
+		mnt_drop_write(dir_path->mnt);
 	}
+
+	return error;
 }
+EXPORT_SYMBOL(path_mknod);
 
 asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode,
 				unsigned dev)
@@ -2086,26 +2097,22 @@ asmlinkage long sys_mknodat(int dfd, con
 	}
 	if (!IS_POSIXACL(nd.path.dentry->d_inode))
 		mode &= ~current->fs->umask;
-	error = may_mknod(mode);
-	if (error)
-		goto out_dput;
-	error = mnt_want_write(nd.path.mnt);
-	if (error)
-		goto out_dput;
 	switch (mode & S_IFMT) {
-		case 0: case S_IFREG:
-			error = vfs_create(nd.path.dentry->d_inode,dentry,mode,&nd);
-			break;
-		case S_IFCHR: case S_IFBLK:
-			error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,
-					new_decode_dev(dev));
-			break;
-		case S_IFIFO: case S_IFSOCK:
-			error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,0);
-			break;
+	case 0: case S_IFREG:
+		error = path_create(&nd.path, dentry, mode, &nd);
+		break;
+	case S_IFCHR: case S_IFBLK:
+		error = path_mknod(&nd.path, dentry, mode, new_decode_dev(dev));
+		break;
+	case S_IFIFO: case S_IFSOCK:
+		error = path_mknod(&nd.path, dentry, mode, 0);
+		break;
+	case S_IFDIR:
+		error = -EPERM;
+		break;
+	default:
+		error = -EINVAL;
 	}
-	mnt_drop_write(nd.path.mnt);
-out_dput:
 	dput(dentry);
 out_unlock:
 	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
@@ -2972,11 +2979,9 @@ EXPORT_SYMBOL(permission);
 EXPORT_SYMBOL(vfs_permission);
 EXPORT_SYMBOL(file_permission);
 EXPORT_SYMBOL(unlock_rename);
-EXPORT_SYMBOL(vfs_create);
 EXPORT_SYMBOL(vfs_follow_link);
 EXPORT_SYMBOL(vfs_link);
 EXPORT_SYMBOL(vfs_mkdir);
-EXPORT_SYMBOL(vfs_mknod);
 EXPORT_SYMBOL(generic_permission);
 EXPORT_SYMBOL(vfs_readlink);
 EXPORT_SYMBOL(vfs_rename);
Index: linux-2.6/include/linux/fs.h
===================================================================
--- linux-2.6.orig/include/linux/fs.h	2008-05-05 11:29:29.000000000 +0200
+++ linux-2.6/include/linux/fs.h	2008-05-05 11:29:29.000000000 +0200
@@ -1124,9 +1124,9 @@ extern void unlock_super(struct super_bl
  * VFS helper functions..
  */
 extern int vfs_permission(struct nameidata *, int);
-extern int vfs_create(struct inode *, struct dentry *, int, struct nameidata *);
+extern int path_create(struct path *, struct dentry *, int, struct nameidata *);
 extern int vfs_mkdir(struct inode *, struct dentry *, int);
-extern int vfs_mknod(struct inode *, struct dentry *, int, dev_t);
+extern int path_mknod(struct path *, struct dentry *, int, dev_t);
 extern int vfs_symlink(struct inode *, struct dentry *, const char *, int);
 extern int vfs_link(struct dentry *, struct inode *, struct dentry *);
 extern int vfs_rmdir(struct inode *, struct dentry *);
Index: linux-2.6/fs/ecryptfs/inode.c
===================================================================
--- linux-2.6.orig/fs/ecryptfs/inode.c	2008-05-05 11:29:24.000000000 +0200
+++ linux-2.6/fs/ecryptfs/inode.c	2008-05-05 11:29:29.000000000 +0200
@@ -61,23 +61,19 @@ static void unlock_dir(struct dentry *di
  * Returns zero on success; non-zero on error condition
  */
 static int
-ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
+ecryptfs_create_underlying_file(struct dentry *lower_dir_dentry,
 				struct dentry *dentry, int mode,
 				struct nameidata *nd)
 {
 	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
-	struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
-	struct dentry *dentry_save;
-	struct vfsmount *vfsmount_save;
+	struct path save;
 	int rc;
 
-	dentry_save = nd->path.dentry;
-	vfsmount_save = nd->path.mnt;
-	nd->path.dentry = lower_dentry;
-	nd->path.mnt = lower_mnt;
-	rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
-	nd->path.dentry = dentry_save;
-	nd->path.mnt = vfsmount_save;
+	save = nd->path;
+	nd->path.mnt = ecryptfs_dentry_to_lower_mnt(dentry);
+	nd->path.dentry = lower_dir_dentry;
+	rc = path_create(&nd->path, lower_dentry, mode, nd);
+	nd->path = save;
 	return rc;
 }
 
@@ -111,7 +107,7 @@ ecryptfs_do_create(struct inode *directo
 		rc = PTR_ERR(lower_dir_dentry);
 		goto out;
 	}
-	rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
+	rc = ecryptfs_create_underlying_file(lower_dir_dentry,
 					     ecryptfs_dentry, mode, nd);
 	if (rc) {
 		printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
@@ -530,20 +526,21 @@ ecryptfs_mknod(struct inode *dir, struct
 {
 	int rc;
 	struct dentry *lower_dentry;
-	struct dentry *lower_dir_dentry;
+	struct path lower_dir;
 
 	lower_dentry = ecryptfs_dentry_to_lower(dentry);
-	lower_dir_dentry = lock_parent(lower_dentry);
-	rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
+	lower_dir.mnt = ecryptfs_dentry_to_lower_mnt(dentry);
+	lower_dir.dentry = lock_parent(lower_dentry);
+	rc = path_mknod(&lower_dir, lower_dentry, mode, dev);
 	if (rc || !lower_dentry->d_inode)
 		goto out;
 	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 	if (rc)
 		goto out;
-	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
-	fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
+	fsstack_copy_attr_times(dir, lower_dir.dentry->d_inode);
+	fsstack_copy_inode_size(dir, lower_dir.dentry->d_inode);
 out:
-	unlock_dir(lower_dir_dentry);
+	unlock_dir(lower_dir.dentry);
 	if (!dentry->d_inode)
 		d_drop(dentry);
 	return rc;
Index: linux-2.6/ipc/mqueue.c
===================================================================
--- linux-2.6.orig/ipc/mqueue.c	2008-05-05 11:29:20.000000000 +0200
+++ linux-2.6/ipc/mqueue.c	2008-05-05 11:29:29.000000000 +0200
@@ -599,6 +599,7 @@ static struct file *do_create(struct den
 {
 	struct mq_attr attr;
 	struct file *result;
+	struct path dir_path;
 	int ret;
 
 	if (u_attr) {
@@ -616,7 +617,10 @@ static struct file *do_create(struct den
 	ret = mnt_want_write(mqueue_mnt);
 	if (ret)
 		goto out;
-	ret = vfs_create(dir->d_inode, dentry, mode, NULL);
+
+	dir_path.mnt = mqueue_mnt;
+	dir_path.dentry = dir;
+	ret = path_create(&dir_path, dentry, mode, NULL);
 	dentry->d_fsdata = NULL;
 	if (ret)
 		goto out_drop_write;
Index: linux-2.6/net/unix/af_unix.c
===================================================================
--- linux-2.6.orig/net/unix/af_unix.c	2008-05-05 11:29:20.000000000 +0200
+++ linux-2.6/net/unix/af_unix.c	2008-05-05 11:29:29.000000000 +0200
@@ -819,11 +819,7 @@ static int unix_bind(struct socket *sock
 		 */
 		mode = S_IFSOCK |
 		       (SOCK_INODE(sock)->i_mode & ~current->fs->umask);
-		err = mnt_want_write(nd.path.mnt);
-		if (err)
-			goto out_mknod_dput;
-		err = vfs_mknod(nd.path.dentry->d_inode, dentry, mode, 0);
-		mnt_drop_write(nd.path.mnt);
+		err = path_mknod(&nd.path, dentry, mode, 0);
 		if (err)
 			goto out_mknod_dput;
 		mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
Index: linux-2.6/fs/nfsd/vfs.c
===================================================================
--- linux-2.6.orig/fs/nfsd/vfs.c	2008-05-05 11:29:24.000000000 +0200
+++ linux-2.6/fs/nfsd/vfs.c	2008-05-05 11:29:29.000000000 +0200
@@ -130,6 +130,12 @@ out:
 	return err;
 }
 
+static void fh_to_path(struct svc_fh *fhp, struct path *path)
+{
+	path->dentry = fhp->fh_dentry;
+	path->mnt = fhp->fh_export->ex_path.mnt;
+}
+
 __be32
 nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
 		   const char *name, unsigned int len,
@@ -1184,6 +1190,7 @@ nfsd_create(struct svc_rqst *rqstp, stru
 		char *fname, int flen, struct iattr *iap,
 		int type, dev_t rdev, struct svc_fh *resfhp)
 {
+	struct path	dir_path;
 	struct dentry	*dentry, *dchild = NULL;
 	struct inode	*dirp;
 	__be32		err;
@@ -1259,13 +1266,11 @@ nfsd_create(struct svc_rqst *rqstp, stru
 	if (host_err)
 		goto out_nfserr;
 
-	/*
-	 * Get the dir op function pointer.
-	 */
+	fh_to_path(fhp, &dir_path);
 	err = 0;
 	switch (type) {
 	case S_IFREG:
-		host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL);
+		host_err = path_create(&dir_path, dchild, iap->ia_mode, NULL);
 		break;
 	case S_IFDIR:
 		host_err = vfs_mkdir(dirp, dchild, iap->ia_mode);
@@ -1274,7 +1279,7 @@ nfsd_create(struct svc_rqst *rqstp, stru
 	case S_IFBLK:
 	case S_IFIFO:
 	case S_IFSOCK:
-		host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev);
+		host_err = path_mknod(&dir_path, dchild, iap->ia_mode, rdev);
 		break;
 	}
 	if (host_err < 0) {
@@ -1316,6 +1321,7 @@ nfsd_create_v3(struct svc_rqst *rqstp, s
 		struct svc_fh *resfhp, int createmode, u32 *verifier,
 	        int *truncp, int *created)
 {
+	struct path 	dir_path;
 	struct dentry	*dentry, *dchild = NULL;
 	struct inode	*dirp;
 	__be32		err;
@@ -1406,7 +1412,8 @@ nfsd_create_v3(struct svc_rqst *rqstp, s
 		goto out;
 	}
 
-	host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL);
+	fh_to_path(fhp, &dir_path);
+	host_err = path_create(&dir_path, dchild, iap->ia_mode, NULL);
 	if (host_err < 0) {
 		mnt_drop_write(fhp->fh_export->ex_path.mnt);
 		goto out_nfserr;

--

[patch 02/10] vfs: add path_mkdir()

[Miklos Szeredi]

[-- Attachment #1: path_mkdir.patch --]
[-- Type: text/plain, Size: 5466 bytes --]

From: Miklos Szeredi <mszeredi@suse.cz>

Introduce path_mkdir().  Make vfs_mkdir() static.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
---
 fs/ecryptfs/inode.c   |   15 ++++++++-------
 fs/namei.c            |   23 +++++++++++++++--------
 fs/nfsd/nfs4recover.c |    6 +-----
 fs/nfsd/vfs.c         |    2 +-
 include/linux/fs.h    |    2 +-
 5 files changed, 26 insertions(+), 22 deletions(-)

Index: linux-2.6/fs/ecryptfs/inode.c
===================================================================
--- linux-2.6.orig/fs/ecryptfs/inode.c	2008-05-05 11:29:29.000000000 +0200
+++ linux-2.6/fs/ecryptfs/inode.c	2008-05-05 11:29:29.000000000 +0200
@@ -478,21 +478,22 @@ static int ecryptfs_mkdir(struct inode *
 {
 	int rc;
 	struct dentry *lower_dentry;
-	struct dentry *lower_dir_dentry;
+	struct path lower_dir;
 
 	lower_dentry = ecryptfs_dentry_to_lower(dentry);
-	lower_dir_dentry = lock_parent(lower_dentry);
-	rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
+	lower_dir.mnt = ecryptfs_dentry_to_lower_mnt(dentry);
+	lower_dir.dentry = lock_parent(lower_dentry);
+	rc = path_mkdir(&lower_dir, lower_dentry, mode);
 	if (rc || !lower_dentry->d_inode)
 		goto out;
 	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 	if (rc)
 		goto out;
-	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
-	fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
-	dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
+	fsstack_copy_attr_times(dir, lower_dir.dentry->d_inode);
+	fsstack_copy_inode_size(dir, lower_dir.dentry->d_inode);
+	dir->i_nlink = lower_dir.dentry->d_inode->i_nlink;
 out:
-	unlock_dir(lower_dir_dentry);
+	unlock_dir(lower_dir.dentry);
 	if (!dentry->d_inode)
 		d_drop(dentry);
 	return rc;
Index: linux-2.6/fs/namei.c
===================================================================
--- linux-2.6.orig/fs/namei.c	2008-05-05 11:29:29.000000000 +0200
+++ linux-2.6/fs/namei.c	2008-05-05 11:29:29.000000000 +0200
@@ -2128,7 +2128,7 @@ asmlinkage long sys_mknod(const char __u
 	return sys_mknodat(AT_FDCWD, filename, mode, dev);
 }
 
-int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+static int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 {
 	int error = may_create(dir, dentry, NULL);
 
@@ -2150,6 +2150,19 @@ int vfs_mkdir(struct inode *dir, struct 
 	return error;
 }
 
+int path_mkdir(struct path *dir_path, struct dentry *dentry, int mode)
+{
+	int error = mnt_want_write(dir_path->mnt);
+
+	if (!error) {
+		error = vfs_mkdir(dir_path->dentry->d_inode, dentry, mode);
+		mnt_drop_write(dir_path->mnt);
+	}
+
+	return error;
+}
+EXPORT_SYMBOL(path_mkdir);
+
 asmlinkage long sys_mkdirat(int dfd, const char __user *pathname, int mode)
 {
 	int error = 0;
@@ -2172,12 +2185,7 @@ asmlinkage long sys_mkdirat(int dfd, con
 
 	if (!IS_POSIXACL(nd.path.dentry->d_inode))
 		mode &= ~current->fs->umask;
-	error = mnt_want_write(nd.path.mnt);
-	if (error)
-		goto out_dput;
-	error = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode);
-	mnt_drop_write(nd.path.mnt);
-out_dput:
+	error = path_mkdir(&nd.path, dentry, mode);
 	dput(dentry);
 out_unlock:
 	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
@@ -2981,7 +2989,6 @@ EXPORT_SYMBOL(file_permission);
 EXPORT_SYMBOL(unlock_rename);
 EXPORT_SYMBOL(vfs_follow_link);
 EXPORT_SYMBOL(vfs_link);
-EXPORT_SYMBOL(vfs_mkdir);
 EXPORT_SYMBOL(generic_permission);
 EXPORT_SYMBOL(vfs_readlink);
 EXPORT_SYMBOL(vfs_rename);
Index: linux-2.6/fs/nfsd/nfs4recover.c
===================================================================
--- linux-2.6.orig/fs/nfsd/nfs4recover.c	2008-05-05 11:29:20.000000000 +0200
+++ linux-2.6/fs/nfsd/nfs4recover.c	2008-05-05 11:29:29.000000000 +0200
@@ -155,11 +155,7 @@ nfsd4_create_clid_dir(struct nfs4_client
 		dprintk("NFSD: nfsd4_create_clid_dir: DIRECTORY EXISTS\n");
 		goto out_put;
 	}
-	status = mnt_want_write(rec_dir.path.mnt);
-	if (status)
-		goto out_put;
-	status = vfs_mkdir(rec_dir.path.dentry->d_inode, dentry, S_IRWXU);
-	mnt_drop_write(rec_dir.path.mnt);
+	status = path_mkdir(&rec_dir.path, dentry, S_IRWXU);
 out_put:
 	dput(dentry);
 out_unlock:
Index: linux-2.6/fs/nfsd/vfs.c
===================================================================
--- linux-2.6.orig/fs/nfsd/vfs.c	2008-05-05 11:29:29.000000000 +0200
+++ linux-2.6/fs/nfsd/vfs.c	2008-05-05 11:29:29.000000000 +0200
@@ -1273,7 +1273,7 @@ nfsd_create(struct svc_rqst *rqstp, stru
 		host_err = path_create(&dir_path, dchild, iap->ia_mode, NULL);
 		break;
 	case S_IFDIR:
-		host_err = vfs_mkdir(dirp, dchild, iap->ia_mode);
+		host_err = path_mkdir(&dir_path, dchild, iap->ia_mode);
 		break;
 	case S_IFCHR:
 	case S_IFBLK:
Index: linux-2.6/include/linux/fs.h
===================================================================
--- linux-2.6.orig/include/linux/fs.h	2008-05-05 11:29:29.000000000 +0200
+++ linux-2.6/include/linux/fs.h	2008-05-05 11:29:29.000000000 +0200
@@ -1125,7 +1125,7 @@ extern void unlock_super(struct super_bl
  */
 extern int vfs_permission(struct nameidata *, int);
 extern int path_create(struct path *, struct dentry *, int, struct nameidata *);
-extern int vfs_mkdir(struct inode *, struct dentry *, int);
+extern int path_mkdir(struct path *, struct dentry *, int);
 extern int path_mknod(struct path *, struct dentry *, int, dev_t);
 extern int vfs_symlink(struct inode *, struct dentry *, const char *, int);
 extern int vfs_link(struct dentry *, struct inode *, struct dentry *);

--

[patch 03/10] vfs: add path_rmdir()

[Miklos Szeredi]

[-- Attachment #1: path_rmdir.patch --]
[-- Type: text/plain, Size: 5868 bytes --]

From: Miklos Szeredi <mszeredi@suse.cz>

Introduce path_rmdir().

The only user of vfs_rmdir() remaining is reiserfs_delete_xattrs().

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
---
 fs/ecryptfs/inode.c   |   13 +++++++------
 fs/namei.c            |   23 +++++++++++++++--------
 fs/nfsd/nfs4recover.c |    3 ++-
 fs/nfsd/vfs.c         |    4 +++-
 include/linux/fs.h    |    2 +-
 5 files changed, 28 insertions(+), 17 deletions(-)

Index: linux-2.6/fs/namei.c
===================================================================
--- linux-2.6.orig/fs/namei.c	2008-05-05 11:29:29.000000000 +0200
+++ linux-2.6/fs/namei.c	2008-05-05 11:29:30.000000000 +0200
@@ -2228,7 +2228,7 @@ void dentry_unhash(struct dentry *dentry
 	spin_unlock(&dcache_lock);
 }
 
-int vfs_rmdir(struct inode *dir, struct dentry *dentry)
+static int vfs_rmdir(struct inode *dir, struct dentry *dentry)
 {
 	int error = may_delete(dir, dentry, 1);
 
@@ -2261,6 +2261,19 @@ int vfs_rmdir(struct inode *dir, struct 
 	return error;
 }
 
+int path_rmdir(struct path *dir_path, struct dentry *dentry)
+{
+	int error = mnt_want_write(dir_path->mnt);
+
+	if (!error) {
+		error = vfs_rmdir(dir_path->dentry->d_inode, dentry);
+		mnt_drop_write(dir_path->mnt);
+	}
+
+	return error;
+}
+EXPORT_SYMBOL(path_rmdir);
+
 static long do_rmdir(int dfd, const char __user *pathname)
 {
 	int error = 0;
@@ -2292,12 +2305,7 @@ static long do_rmdir(int dfd, const char
 	error = PTR_ERR(dentry);
 	if (IS_ERR(dentry))
 		goto exit2;
-	error = mnt_want_write(nd.path.mnt);
-	if (error)
-		goto exit3;
-	error = vfs_rmdir(nd.path.dentry->d_inode, dentry);
-	mnt_drop_write(nd.path.mnt);
-exit3:
+	error = path_rmdir(&nd.path, dentry);
 	dput(dentry);
 exit2:
 	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
@@ -2992,7 +3000,6 @@ EXPORT_SYMBOL(vfs_link);
 EXPORT_SYMBOL(generic_permission);
 EXPORT_SYMBOL(vfs_readlink);
 EXPORT_SYMBOL(vfs_rename);
-EXPORT_SYMBOL(vfs_rmdir);
 EXPORT_SYMBOL(vfs_symlink);
 EXPORT_SYMBOL(vfs_unlink);
 EXPORT_SYMBOL(dentry_unhash);
Index: linux-2.6/fs/ecryptfs/inode.c
===================================================================
--- linux-2.6.orig/fs/ecryptfs/inode.c	2008-05-05 11:29:29.000000000 +0200
+++ linux-2.6/fs/ecryptfs/inode.c	2008-05-05 11:29:30.000000000 +0200
@@ -502,20 +502,21 @@ out:
 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 {
 	struct dentry *lower_dentry;
-	struct dentry *lower_dir_dentry;
+	struct path lower_dir;
 	int rc;
 
 	lower_dentry = ecryptfs_dentry_to_lower(dentry);
 	dget(dentry);
-	lower_dir_dentry = lock_parent(lower_dentry);
+	lower_dir.mnt = ecryptfs_dentry_to_lower_mnt(dentry);
+	lower_dir.dentry = lock_parent(lower_dentry);
 	dget(lower_dentry);
-	rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
+	rc = path_rmdir(&lower_dir, lower_dentry);
 	dput(lower_dentry);
 	if (!rc)
 		d_delete(lower_dentry);
-	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
-	dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
-	unlock_dir(lower_dir_dentry);
+	fsstack_copy_attr_times(dir, lower_dir.dentry->d_inode);
+	dir->i_nlink = lower_dir.dentry->d_inode->i_nlink;
+	unlock_dir(lower_dir.dentry);
 	if (!rc)
 		d_drop(dentry);
 	dput(dentry);
Index: linux-2.6/fs/nfsd/nfs4recover.c
===================================================================
--- linux-2.6.orig/fs/nfsd/nfs4recover.c	2008-05-05 11:29:29.000000000 +0200
+++ linux-2.6/fs/nfsd/nfs4recover.c	2008-05-05 11:29:30.000000000 +0200
@@ -267,6 +267,7 @@ nfsd4_remove_clid_file(struct dentry *di
 static int
 nfsd4_clear_clid_dir(struct dentry *dir, struct dentry *dentry)
 {
+	struct path dir_path = { .dentry = dir, .mnt = rec_dir.path.mnt };
 	int status;
 
 	/* For now this directory should already be empty, but we empty it of
@@ -274,7 +275,7 @@ nfsd4_clear_clid_dir(struct dentry *dir,
 	 * a kernel from the future.... */
 	nfsd4_list_rec_dir(dentry, nfsd4_remove_clid_file);
 	mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
-	status = vfs_rmdir(dir->d_inode, dentry);
+	status = path_rmdir(&dir_path, dentry);
 	mutex_unlock(&dir->d_inode->i_mutex);
 	return status;
 }
Index: linux-2.6/fs/nfsd/vfs.c
===================================================================
--- linux-2.6.orig/fs/nfsd/vfs.c	2008-05-05 11:29:29.000000000 +0200
+++ linux-2.6/fs/nfsd/vfs.c	2008-05-05 11:29:30.000000000 +0200
@@ -1764,6 +1764,7 @@ __be32
 nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
 				char *fname, int flen)
 {
+	struct path 	dir_path;
 	struct dentry	*dentry, *rdentry;
 	struct inode	*dirp;
 	__be32		err;
@@ -1798,6 +1799,7 @@ nfsd_unlink(struct svc_rqst *rqstp, stru
 	if (host_err)
 		goto out_nfserr;
 
+	fh_to_path(fhp, &dir_path);
 	if (type != S_IFDIR) { /* It's UNLINK */
 #ifdef MSNFS
 		if ((fhp->fh_export->ex_flags & NFSEXP_MSNFS) &&
@@ -1807,7 +1809,7 @@ nfsd_unlink(struct svc_rqst *rqstp, stru
 #endif
 		host_err = vfs_unlink(dirp, rdentry);
 	} else { /* It's RMDIR */
-		host_err = vfs_rmdir(dirp, rdentry);
+		host_err = path_rmdir(&dir_path, rdentry);
 	}
 
 	dput(rdentry);
Index: linux-2.6/include/linux/fs.h
===================================================================
--- linux-2.6.orig/include/linux/fs.h	2008-05-05 11:29:29.000000000 +0200
+++ linux-2.6/include/linux/fs.h	2008-05-05 11:29:30.000000000 +0200
@@ -1129,7 +1129,7 @@ extern int path_mkdir(struct path *, str
 extern int path_mknod(struct path *, struct dentry *, int, dev_t);
 extern int vfs_symlink(struct inode *, struct dentry *, const char *, int);
 extern int vfs_link(struct dentry *, struct inode *, struct dentry *);
-extern int vfs_rmdir(struct inode *, struct dentry *);
+extern int path_rmdir(struct path *, struct dentry *);
 extern int vfs_unlink(struct inode *, struct dentry *);
 extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);
 

--

[patch 04/10] vfs: add path_unlink()

[Miklos Szeredi]

[-- Attachment #1: path_unlink.patch --]
[-- Type: text/plain, Size: 7192 bytes --]

From: Miklos Szeredi <mszeredi@suse.cz>

Introduce path_unlink().  Make vfs_unlink() static.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
---
 fs/ecryptfs/inode.c   |   12 ++++++------
 fs/namei.c            |   22 +++++++++++++++-------
 fs/nfsd/nfs4recover.c |    3 ++-
 fs/nfsd/vfs.c         |   12 ++----------
 include/linux/fs.h    |    2 +-
 ipc/mqueue.c          |   10 +++++-----
 6 files changed, 31 insertions(+), 30 deletions(-)

Index: linux-2.6/fs/ecryptfs/inode.c
===================================================================
--- linux-2.6.orig/fs/ecryptfs/inode.c	2008-05-05 11:29:30.000000000 +0200
+++ linux-2.6/fs/ecryptfs/inode.c	2008-05-05 11:29:31.000000000 +0200
@@ -415,22 +415,22 @@ static int ecryptfs_unlink(struct inode 
 {
 	int rc = 0;
 	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
-	struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
-	struct dentry *lower_dir_dentry;
+	struct path lower_dir;
 
-	lower_dir_dentry = lock_parent(lower_dentry);
-	rc = vfs_unlink(lower_dir_inode, lower_dentry);
+	lower_dir.mnt = ecryptfs_dentry_to_lower_mnt(dentry);
+	lower_dir.dentry = lock_parent(lower_dentry);
+	rc = path_unlink(&lower_dir, lower_dentry);
 	if (rc) {
 		printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 		goto out_unlock;
 	}
-	fsstack_copy_attr_times(dir, lower_dir_inode);
+	fsstack_copy_attr_times(dir, lower_dir.dentry->d_inode);
 	dentry->d_inode->i_nlink =
 		ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
 	dentry->d_inode->i_ctime = dir->i_ctime;
 	d_drop(dentry);
 out_unlock:
-	unlock_dir(lower_dir_dentry);
+	unlock_dir(lower_dir.dentry);
 	return rc;
 }
 
Index: linux-2.6/fs/namei.c
===================================================================
--- linux-2.6.orig/fs/namei.c	2008-05-05 11:29:30.000000000 +0200
+++ linux-2.6/fs/namei.c	2008-05-05 11:29:31.000000000 +0200
@@ -2321,7 +2321,7 @@ asmlinkage long sys_rmdir(const char __u
 	return do_rmdir(AT_FDCWD, pathname);
 }
 
-int vfs_unlink(struct inode *dir, struct dentry *dentry)
+static int vfs_unlink(struct inode *dir, struct dentry *dentry)
 {
 	int error = may_delete(dir, dentry, 0);
 
@@ -2352,6 +2352,19 @@ int vfs_unlink(struct inode *dir, struct
 	return error;
 }
 
+int path_unlink(struct path *dir_path, struct dentry *dentry)
+{
+	int error = mnt_want_write(dir_path->mnt);
+
+	if (!error) {
+		error = vfs_unlink(dir_path->dentry->d_inode, dentry);
+		mnt_drop_write(dir_path->mnt);
+	}
+
+	return error;
+}
+EXPORT_SYMBOL(path_unlink);
+
 /*
  * Make sure that the actual truncation of the file will occur outside its
  * directory's i_mutex.  Truncate can take a long time if there is a lot of
@@ -2386,11 +2399,7 @@ static long do_unlinkat(int dfd, const c
 		inode = dentry->d_inode;
 		if (inode)
 			atomic_inc(&inode->i_count);
-		error = mnt_want_write(nd.path.mnt);
-		if (error)
-			goto exit2;
-		error = vfs_unlink(nd.path.dentry->d_inode, dentry);
-		mnt_drop_write(nd.path.mnt);
+		error = path_unlink(&nd.path, dentry);
 	exit2:
 		dput(dentry);
 	}
@@ -3001,6 +3010,5 @@ EXPORT_SYMBOL(generic_permission);
 EXPORT_SYMBOL(vfs_readlink);
 EXPORT_SYMBOL(vfs_rename);
 EXPORT_SYMBOL(vfs_symlink);
-EXPORT_SYMBOL(vfs_unlink);
 EXPORT_SYMBOL(dentry_unhash);
 EXPORT_SYMBOL(generic_readlink);
Index: linux-2.6/fs/nfsd/nfs4recover.c
===================================================================
--- linux-2.6.orig/fs/nfsd/nfs4recover.c	2008-05-05 11:29:30.000000000 +0200
+++ linux-2.6/fs/nfsd/nfs4recover.c	2008-05-05 11:29:31.000000000 +0200
@@ -252,6 +252,7 @@ out:
 static int
 nfsd4_remove_clid_file(struct dentry *dir, struct dentry *dentry)
 {
+	struct path dir_path = { .dentry = dir, .mnt = rec_dir.path.mnt };
 	int status;
 
 	if (!S_ISREG(dir->d_inode->i_mode)) {
@@ -259,7 +260,7 @@ nfsd4_remove_clid_file(struct dentry *di
 		return -EINVAL;
 	}
 	mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
-	status = vfs_unlink(dir->d_inode, dentry);
+	status = path_unlink(&dir_path, dentry);
 	mutex_unlock(&dir->d_inode->i_mutex);
 	return status;
 }
Index: linux-2.6/fs/nfsd/vfs.c
===================================================================
--- linux-2.6.orig/fs/nfsd/vfs.c	2008-05-05 11:29:30.000000000 +0200
+++ linux-2.6/fs/nfsd/vfs.c	2008-05-05 11:29:31.000000000 +0200
@@ -1766,7 +1766,6 @@ nfsd_unlink(struct svc_rqst *rqstp, stru
 {
 	struct path 	dir_path;
 	struct dentry	*dentry, *rdentry;
-	struct inode	*dirp;
 	__be32		err;
 	int		host_err;
 
@@ -1779,7 +1778,6 @@ nfsd_unlink(struct svc_rqst *rqstp, stru
 
 	fh_lock_nested(fhp, I_MUTEX_PARENT);
 	dentry = fhp->fh_dentry;
-	dirp = dentry->d_inode;
 
 	rdentry = lookup_one_len(fname, dentry, flen);
 	host_err = PTR_ERR(rdentry);
@@ -1795,10 +1793,6 @@ nfsd_unlink(struct svc_rqst *rqstp, stru
 	if (!type)
 		type = rdentry->d_inode->i_mode & S_IFMT;
 
-	host_err = mnt_want_write(fhp->fh_export->ex_path.mnt);
-	if (host_err)
-		goto out_nfserr;
-
 	fh_to_path(fhp, &dir_path);
 	if (type != S_IFDIR) { /* It's UNLINK */
 #ifdef MSNFS
@@ -1807,7 +1801,7 @@ nfsd_unlink(struct svc_rqst *rqstp, stru
 			host_err = -EPERM;
 		} else
 #endif
-		host_err = vfs_unlink(dirp, rdentry);
+		host_err = path_unlink(&dir_path, rdentry);
 	} else { /* It's RMDIR */
 		host_err = path_rmdir(&dir_path, rdentry);
 	}
@@ -1815,12 +1809,10 @@ nfsd_unlink(struct svc_rqst *rqstp, stru
 	dput(rdentry);
 
 	if (host_err)
-		goto out_drop;
+		goto out_nfserr;
 	if (EX_ISSYNC(fhp->fh_export))
 		host_err = nfsd_sync_dir(dentry);
 
-out_drop:
-	mnt_drop_write(fhp->fh_export->ex_path.mnt);
 out_nfserr:
 	err = nfserrno(host_err);
 out:
Index: linux-2.6/include/linux/fs.h
===================================================================
--- linux-2.6.orig/include/linux/fs.h	2008-05-05 11:29:30.000000000 +0200
+++ linux-2.6/include/linux/fs.h	2008-05-05 11:29:31.000000000 +0200
@@ -1130,7 +1130,7 @@ extern int path_mknod(struct path *, str
 extern int vfs_symlink(struct inode *, struct dentry *, const char *, int);
 extern int vfs_link(struct dentry *, struct inode *, struct dentry *);
 extern int path_rmdir(struct path *, struct dentry *);
-extern int vfs_unlink(struct inode *, struct dentry *);
+extern int path_unlink(struct path *, struct dentry *);
 extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);
 
 /*
Index: linux-2.6/ipc/mqueue.c
===================================================================
--- linux-2.6.orig/ipc/mqueue.c	2008-05-05 11:29:29.000000000 +0200
+++ linux-2.6/ipc/mqueue.c	2008-05-05 11:29:31.000000000 +0200
@@ -736,6 +736,7 @@ asmlinkage long sys_mq_unlink(const char
 	char *name;
 	struct dentry *dentry;
 	struct inode *inode = NULL;
+	struct path dir_path;
 
 	name = getname(u_name);
 	if (IS_ERR(name))
@@ -757,11 +758,10 @@ asmlinkage long sys_mq_unlink(const char
 	inode = dentry->d_inode;
 	if (inode)
 		atomic_inc(&inode->i_count);
-	err = mnt_want_write(mqueue_mnt);
-	if (err)
-		goto out_err;
-	err = vfs_unlink(dentry->d_parent->d_inode, dentry);
-	mnt_drop_write(mqueue_mnt);
+
+	dir_path.mnt = mqueue_mnt;
+	dir_path.dentry = dentry->d_parent;
+	err = path_unlink(&dir_path, dentry);
 out_err:
 	dput(dentry);
 

--

[patch 05/10] vfs: add path_symlink()

[Miklos Szeredi]

[-- Attachment #1: path_symlink.patch --]
[-- Type: text/plain, Size: 6302 bytes --]

From: Miklos Szeredi <mszeredi@suse.cz>

Introduce path_symlink().  Make vfs_symlink() static.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
---
 fs/ecryptfs/inode.c |   14 +++++++-------
 fs/namei.c          |   26 ++++++++++++++++++--------
 fs/nfsd/vfs.c       |   12 ++++--------
 include/linux/fs.h  |    2 +-
 4 files changed, 30 insertions(+), 24 deletions(-)

Index: linux-2.6/fs/ecryptfs/inode.c
===================================================================
--- linux-2.6.orig/fs/ecryptfs/inode.c	2008-05-05 11:29:31.000000000 +0200
+++ linux-2.6/fs/ecryptfs/inode.c	2008-05-05 11:29:31.000000000 +0200
@@ -439,7 +439,7 @@ static int ecryptfs_symlink(struct inode
 {
 	int rc;
 	struct dentry *lower_dentry;
-	struct dentry *lower_dir_dentry;
+	struct path lower_dir;
 	umode_t mode;
 	char *encoded_symname;
 	int encoded_symlen;
@@ -447,7 +447,8 @@ static int ecryptfs_symlink(struct inode
 
 	lower_dentry = ecryptfs_dentry_to_lower(dentry);
 	dget(lower_dentry);
-	lower_dir_dentry = lock_parent(lower_dentry);
+	lower_dir.mnt = ecryptfs_dentry_to_lower_mnt(dentry);
+	lower_dir.dentry = lock_parent(lower_dentry);
 	mode = S_IALLUGO;
 	encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
 						  strlen(symname),
@@ -456,18 +457,17 @@ static int ecryptfs_symlink(struct inode
 		rc = encoded_symlen;
 		goto out_lock;
 	}
-	rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
-			 encoded_symname, mode);
+	rc = path_symlink(&lower_dir, lower_dentry, encoded_symname, mode);
 	kfree(encoded_symname);
 	if (rc || !lower_dentry->d_inode)
 		goto out_lock;
 	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 	if (rc)
 		goto out_lock;
-	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
-	fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
+	fsstack_copy_attr_times(dir, lower_dir.dentry->d_inode);
+	fsstack_copy_inode_size(dir, lower_dir.dentry->d_inode);
 out_lock:
-	unlock_dir(lower_dir_dentry);
+	unlock_dir(lower_dir.dentry);
 	dput(lower_dentry);
 	if (!dentry->d_inode)
 		d_drop(dentry);
Index: linux-2.6/fs/namei.c
===================================================================
--- linux-2.6.orig/fs/namei.c	2008-05-05 11:29:31.000000000 +0200
+++ linux-2.6/fs/namei.c	2008-05-05 11:29:31.000000000 +0200
@@ -2434,7 +2434,7 @@ asmlinkage long sys_unlink(const char __
 	return do_unlinkat(AT_FDCWD, pathname);
 }
 
-int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname, int mode)
+static int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname, int mode)
 {
 	int error = may_create(dir, dentry, NULL);
 
@@ -2455,6 +2455,22 @@ int vfs_symlink(struct inode *dir, struc
 	return error;
 }
 
+int path_symlink(struct path *dir_path, struct dentry *dentry,
+		 const char *oldname, int mode)
+{
+	int error = mnt_want_write(dir_path->mnt);
+
+	if (!error) {
+		struct inode *dir = dir_path->dentry->d_inode;
+
+		error = vfs_symlink(dir, dentry, oldname, mode);
+		mnt_drop_write(dir_path->mnt);
+	}
+
+	return error;
+}
+EXPORT_SYMBOL(path_symlink);
+
 asmlinkage long sys_symlinkat(const char __user *oldname,
 			      int newdfd, const char __user *newname)
 {
@@ -2480,12 +2496,7 @@ asmlinkage long sys_symlinkat(const char
 	if (IS_ERR(dentry))
 		goto out_unlock;
 
-	error = mnt_want_write(nd.path.mnt);
-	if (error)
-		goto out_dput;
-	error = vfs_symlink(nd.path.dentry->d_inode, dentry, from, S_IALLUGO);
-	mnt_drop_write(nd.path.mnt);
-out_dput:
+	error = path_symlink(&nd.path, dentry, from, S_IALLUGO);
 	dput(dentry);
 out_unlock:
 	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
@@ -3009,6 +3020,5 @@ EXPORT_SYMBOL(vfs_link);
 EXPORT_SYMBOL(generic_permission);
 EXPORT_SYMBOL(vfs_readlink);
 EXPORT_SYMBOL(vfs_rename);
-EXPORT_SYMBOL(vfs_symlink);
 EXPORT_SYMBOL(dentry_unhash);
 EXPORT_SYMBOL(generic_readlink);
Index: linux-2.6/fs/nfsd/vfs.c
===================================================================
--- linux-2.6.orig/fs/nfsd/vfs.c	2008-05-05 11:29:31.000000000 +0200
+++ linux-2.6/fs/nfsd/vfs.c	2008-05-05 11:29:31.000000000 +0200
@@ -1518,6 +1518,7 @@ nfsd_symlink(struct svc_rqst *rqstp, str
 				struct svc_fh *resfhp,
 				struct iattr *iap)
 {
+	struct path 	dir_path;
 	struct dentry	*dentry, *dnew;
 	__be32		err, cerr;
 	int		host_err;
@@ -1545,10 +1546,7 @@ nfsd_symlink(struct svc_rqst *rqstp, str
 	if (iap && (iap->ia_valid & ATTR_MODE))
 		mode = iap->ia_mode & S_IALLUGO;
 
-	host_err = mnt_want_write(fhp->fh_export->ex_path.mnt);
-	if (host_err)
-		goto out_nfserr;
-
+	fh_to_path(fhp, &dir_path);
 	if (unlikely(path[plen] != 0)) {
 		char *path_alloced = kmalloc(plen+1, GFP_KERNEL);
 		if (path_alloced == NULL)
@@ -1556,11 +1554,11 @@ nfsd_symlink(struct svc_rqst *rqstp, str
 		else {
 			strncpy(path_alloced, path, plen);
 			path_alloced[plen] = 0;
-			host_err = vfs_symlink(dentry->d_inode, dnew, path_alloced, mode);
+			host_err = path_symlink(&dir_path, dnew, path_alloced, mode);
 			kfree(path_alloced);
 		}
 	} else
-		host_err = vfs_symlink(dentry->d_inode, dnew, path, mode);
+		host_err = path_symlink(&dir_path, dnew, path, mode);
 
 	if (!host_err) {
 		if (EX_ISSYNC(fhp->fh_export))
@@ -1569,8 +1567,6 @@ nfsd_symlink(struct svc_rqst *rqstp, str
 	err = nfserrno(host_err);
 	fh_unlock(fhp);
 
-	mnt_drop_write(fhp->fh_export->ex_path.mnt);
-
 	cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp);
 	dput(dnew);
 	if (err==0) err = cerr;
Index: linux-2.6/include/linux/fs.h
===================================================================
--- linux-2.6.orig/include/linux/fs.h	2008-05-05 11:29:31.000000000 +0200
+++ linux-2.6/include/linux/fs.h	2008-05-05 11:29:31.000000000 +0200
@@ -1127,7 +1127,7 @@ extern int vfs_permission(struct nameida
 extern int path_create(struct path *, struct dentry *, int, struct nameidata *);
 extern int path_mkdir(struct path *, struct dentry *, int);
 extern int path_mknod(struct path *, struct dentry *, int, dev_t);
-extern int vfs_symlink(struct inode *, struct dentry *, const char *, int);
+extern int path_symlink(struct path *, struct dentry *, const char *, int);
 extern int vfs_link(struct dentry *, struct inode *, struct dentry *);
 extern int path_rmdir(struct path *, struct dentry *);
 extern int path_unlink(struct path *, struct dentry *);

--

[patch 06/10] vfs: add path_link()

[Miklos Szeredi]

[-- Attachment #1: path_link.patch --]
[-- Type: text/plain, Size: 5971 bytes --]

From: Miklos Szeredi <mszeredi@suse.cz>

Introduce path_link().  Make vfs_link() static.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
---
 fs/ecryptfs/inode.c |   10 +++++-----
 fs/namei.c          |   26 ++++++++++++++++++--------
 fs/nfsd/vfs.c       |   14 ++++----------
 include/linux/fs.h  |    2 +-
 4 files changed, 28 insertions(+), 24 deletions(-)

Index: linux-2.6/fs/ecryptfs/inode.c
===================================================================
--- linux-2.6.orig/fs/ecryptfs/inode.c	2008-05-05 11:29:31.000000000 +0200
+++ linux-2.6/fs/ecryptfs/inode.c	2008-05-05 11:29:32.000000000 +0200
@@ -379,7 +379,7 @@ static int ecryptfs_link(struct dentry *
 {
 	struct dentry *lower_old_dentry;
 	struct dentry *lower_new_dentry;
-	struct dentry *lower_dir_dentry;
+	struct path lower_dir;
 	u64 file_size_save;
 	int rc;
 
@@ -388,9 +388,9 @@ static int ecryptfs_link(struct dentry *
 	lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 	dget(lower_old_dentry);
 	dget(lower_new_dentry);
-	lower_dir_dentry = lock_parent(lower_new_dentry);
-	rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
-		      lower_new_dentry);
+	lower_dir.mnt = ecryptfs_dentry_to_lower_mnt(new_dentry);
+	lower_dir.dentry = lock_parent(lower_new_dentry);
+	rc = path_link(lower_old_dentry, &lower_dir, lower_new_dentry);
 	if (rc || !lower_new_dentry->d_inode)
 		goto out_lock;
 	rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
@@ -402,7 +402,7 @@ static int ecryptfs_link(struct dentry *
 		ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
 	i_size_write(new_dentry->d_inode, file_size_save);
 out_lock:
-	unlock_dir(lower_dir_dentry);
+	unlock_dir(lower_dir.dentry);
 	dput(lower_new_dentry);
 	dput(lower_old_dentry);
 	d_drop(lower_old_dentry);
Index: linux-2.6/fs/namei.c
===================================================================
--- linux-2.6.orig/fs/namei.c	2008-05-05 11:29:31.000000000 +0200
+++ linux-2.6/fs/namei.c	2008-05-05 11:29:32.000000000 +0200
@@ -2513,7 +2513,7 @@ asmlinkage long sys_symlink(const char _
 	return sys_symlinkat(oldname, AT_FDCWD, newname);
 }
 
-int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry)
+static int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry)
 {
 	struct inode *inode = old_dentry->d_inode;
 	int error;
@@ -2551,6 +2551,22 @@ int vfs_link(struct dentry *old_dentry, 
 	return error;
 }
 
+int path_link(struct dentry *old_dentry, struct path *dir_path,
+	      struct dentry *new_dentry)
+{
+	int error = mnt_want_write(dir_path->mnt);
+
+	if (!error) {
+		struct inode *dir = dir_path->dentry->d_inode;
+
+		error = vfs_link(old_dentry, dir, new_dentry);
+		mnt_drop_write(dir_path->mnt);
+	}
+
+	return error;
+}
+EXPORT_SYMBOL(path_link);
+
 /*
  * Hardlinks are often used in delicate situations.  We avoid
  * security-related surprises by not following symlinks on the
@@ -2591,12 +2607,7 @@ asmlinkage long sys_linkat(int olddfd, c
 	error = PTR_ERR(new_dentry);
 	if (IS_ERR(new_dentry))
 		goto out_unlock;
-	error = mnt_want_write(nd.path.mnt);
-	if (error)
-		goto out_dput;
-	error = vfs_link(old_nd.path.dentry, nd.path.dentry->d_inode, new_dentry);
-	mnt_drop_write(nd.path.mnt);
-out_dput:
+	error = path_link(old_nd.path.dentry, &nd.path, new_dentry);
 	dput(new_dentry);
 out_unlock:
 	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
@@ -3016,7 +3027,6 @@ EXPORT_SYMBOL(vfs_permission);
 EXPORT_SYMBOL(file_permission);
 EXPORT_SYMBOL(unlock_rename);
 EXPORT_SYMBOL(vfs_follow_link);
-EXPORT_SYMBOL(vfs_link);
 EXPORT_SYMBOL(generic_permission);
 EXPORT_SYMBOL(vfs_readlink);
 EXPORT_SYMBOL(vfs_rename);
Index: linux-2.6/fs/nfsd/vfs.c
===================================================================
--- linux-2.6.orig/fs/nfsd/vfs.c	2008-05-05 11:29:31.000000000 +0200
+++ linux-2.6/fs/nfsd/vfs.c	2008-05-05 11:29:32.000000000 +0200
@@ -1586,8 +1586,9 @@ __be32
 nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
 				char *name, int len, struct svc_fh *tfhp)
 {
+	struct path 	dir_path;
 	struct dentry	*ddir, *dnew, *dold;
-	struct inode	*dirp, *dest;
+	struct inode	*dest;
 	__be32		err;
 	int		host_err;
 
@@ -1607,7 +1608,6 @@ nfsd_link(struct svc_rqst *rqstp, struct
 
 	fh_lock_nested(ffhp, I_MUTEX_PARENT);
 	ddir = ffhp->fh_dentry;
-	dirp = ddir->d_inode;
 
 	dnew = lookup_one_len(name, ddir, len);
 	host_err = PTR_ERR(dnew);
@@ -1617,12 +1617,8 @@ nfsd_link(struct svc_rqst *rqstp, struct
 	dold = tfhp->fh_dentry;
 	dest = dold->d_inode;
 
-	host_err = mnt_want_write(tfhp->fh_export->ex_path.mnt);
-	if (host_err) {
-		err = nfserrno(host_err);
-		goto out_dput;
-	}
-	host_err = vfs_link(dold, dirp, dnew);
+	fh_to_path(ffhp, &dir_path);
+	host_err = path_link(dold, &dir_path, dnew);
 	if (!host_err) {
 		if (EX_ISSYNC(ffhp->fh_export)) {
 			err = nfserrno(nfsd_sync_dir(ddir));
@@ -1635,8 +1631,6 @@ nfsd_link(struct svc_rqst *rqstp, struct
 		else
 			err = nfserrno(host_err);
 	}
-	mnt_drop_write(tfhp->fh_export->ex_path.mnt);
-out_dput:
 	dput(dnew);
 out_unlock:
 	fh_unlock(ffhp);
Index: linux-2.6/include/linux/fs.h
===================================================================
--- linux-2.6.orig/include/linux/fs.h	2008-05-05 11:29:31.000000000 +0200
+++ linux-2.6/include/linux/fs.h	2008-05-05 11:29:32.000000000 +0200
@@ -1128,7 +1128,7 @@ extern int path_create(struct path *, st
 extern int path_mkdir(struct path *, struct dentry *, int);
 extern int path_mknod(struct path *, struct dentry *, int, dev_t);
 extern int path_symlink(struct path *, struct dentry *, const char *, int);
-extern int vfs_link(struct dentry *, struct inode *, struct dentry *);
+extern int path_link(struct dentry *, struct path *, struct dentry *);
 extern int path_rmdir(struct path *, struct dentry *);
 extern int path_unlink(struct path *, struct dentry *);
 extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);

--

[patch 07/10] vfs: add path_rename()

[Miklos Szeredi]

[-- Attachment #1: path_rename.patch --]
[-- Type: text/plain, Size: 6710 bytes --]

From: Miklos Szeredi <mszeredi@suse.cz>

Introduce path_rename().  Make vfs_rename() static.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
---
 fs/ecryptfs/inode.c |   22 ++++++++++++----------
 fs/namei.c          |   33 ++++++++++++++++++++++++---------
 fs/nfsd/vfs.c       |   19 +++++--------------
 include/linux/fs.h  |    3 ++-
 4 files changed, 43 insertions(+), 34 deletions(-)

Index: linux-2.6/fs/ecryptfs/inode.c
===================================================================
--- linux-2.6.orig/fs/ecryptfs/inode.c	2008-05-05 11:29:32.000000000 +0200
+++ linux-2.6/fs/ecryptfs/inode.c	2008-05-05 11:29:32.000000000 +0200
@@ -555,25 +555,27 @@ ecryptfs_rename(struct inode *old_dir, s
 	int rc;
 	struct dentry *lower_old_dentry;
 	struct dentry *lower_new_dentry;
-	struct dentry *lower_old_dir_dentry;
-	struct dentry *lower_new_dir_dentry;
+	struct path lower_old_dir;
+	struct path lower_new_dir;
 
 	lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 	lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 	dget(lower_old_dentry);
 	dget(lower_new_dentry);
-	lower_old_dir_dentry = dget_parent(lower_old_dentry);
-	lower_new_dir_dentry = dget_parent(lower_new_dentry);
-	lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
-	rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
-			lower_new_dir_dentry->d_inode, lower_new_dentry);
+	lower_old_dir.mnt = ecryptfs_dentry_to_lower_mnt(old_dentry);
+	lower_old_dir.dentry = dget_parent(lower_old_dentry);
+	lower_new_dir.mnt = ecryptfs_dentry_to_lower_mnt(new_dentry);
+	lower_new_dir.dentry = dget_parent(lower_new_dentry);
+	lock_rename(lower_old_dir.dentry, lower_new_dir.dentry);
+	rc = path_rename(&lower_old_dir, lower_old_dentry,
+			 &lower_new_dir, lower_new_dentry);
 	if (rc)
 		goto out_lock;
-	fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
+	fsstack_copy_attr_all(new_dir, lower_new_dir.dentry->d_inode, NULL);
 	if (new_dir != old_dir)
-		fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
+		fsstack_copy_attr_all(old_dir, lower_old_dir.dentry->d_inode, NULL);
 out_lock:
-	unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
+	unlock_rename(lower_old_dir.dentry, lower_new_dir.dentry);
 	dput(lower_new_dentry->d_parent);
 	dput(lower_old_dentry->d_parent);
 	dput(lower_new_dentry);
Index: linux-2.6/fs/namei.c
===================================================================
--- linux-2.6.orig/fs/namei.c	2008-05-05 11:29:32.000000000 +0200
+++ linux-2.6/fs/namei.c	2008-05-05 11:29:32.000000000 +0200
@@ -2729,8 +2729,8 @@ static int vfs_rename_other(struct inode
 	return error;
 }
 
-int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
-	       struct inode *new_dir, struct dentry *new_dentry)
+static int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
+		      struct inode *new_dir, struct dentry *new_dentry)
 {
 	int error;
 	int is_dir = S_ISDIR(old_dentry->d_inode->i_mode);
@@ -2772,6 +2772,27 @@ int vfs_rename(struct inode *old_dir, st
 	return error;
 }
 
+int path_rename(struct path *old_dir_path, struct dentry *old_dentry,
+		struct path *new_dir_path, struct dentry *new_dentry)
+{
+	int error;
+	struct vfsmount *mnt = old_dir_path->mnt;
+
+	BUG_ON(mnt != new_dir_path->mnt);
+
+	error = mnt_want_write(mnt);
+	if (!error) {
+		struct inode *old_dir = old_dir_path->dentry->d_inode;
+		struct inode *new_dir = new_dir_path->dentry->d_inode;
+
+		error = vfs_rename(old_dir, old_dentry, new_dir, new_dentry);
+		mnt_drop_write(mnt);
+	}
+
+	return error;
+}
+EXPORT_SYMBOL(path_rename);
+
 static int do_rename(int olddfd, const char *oldname,
 			int newdfd, const char *newname)
 {
@@ -2833,12 +2854,7 @@ static int do_rename(int olddfd, const c
 	if (new_dentry == trap)
 		goto exit5;
 
-	error = mnt_want_write(oldnd.path.mnt);
-	if (error)
-		goto exit5;
-	error = vfs_rename(old_dir->d_inode, old_dentry,
-				   new_dir->d_inode, new_dentry);
-	mnt_drop_write(oldnd.path.mnt);
+	error = path_rename(&oldnd.path, old_dentry, &newnd.path, new_dentry);
 exit5:
 	dput(new_dentry);
 exit4:
@@ -3029,6 +3045,5 @@ EXPORT_SYMBOL(unlock_rename);
 EXPORT_SYMBOL(vfs_follow_link);
 EXPORT_SYMBOL(generic_permission);
 EXPORT_SYMBOL(vfs_readlink);
-EXPORT_SYMBOL(vfs_rename);
 EXPORT_SYMBOL(dentry_unhash);
 EXPORT_SYMBOL(generic_readlink);
Index: linux-2.6/fs/nfsd/vfs.c
===================================================================
--- linux-2.6.orig/fs/nfsd/vfs.c	2008-05-05 11:29:32.000000000 +0200
+++ linux-2.6/fs/nfsd/vfs.c	2008-05-05 11:29:32.000000000 +0200
@@ -1650,8 +1650,9 @@ __be32
 nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
 			    struct svc_fh *tfhp, char *tname, int tlen)
 {
+	struct path 	old_dir_path;
+	struct path	new_dir_path;
 	struct dentry	*fdentry, *tdentry, *odentry, *ndentry, *trap;
-	struct inode	*fdir, *tdir;
 	__be32		err;
 	int		host_err;
 
@@ -1663,10 +1664,7 @@ nfsd_rename(struct svc_rqst *rqstp, stru
 		goto out;
 
 	fdentry = ffhp->fh_dentry;
-	fdir = fdentry->d_inode;
-
 	tdentry = tfhp->fh_dentry;
-	tdir = tdentry->d_inode;
 
 	err = (rqstp->rq_vers == 2) ? nfserr_acces : nfserr_xdev;
 	if (ffhp->fh_export != tfhp->fh_export)
@@ -1710,22 +1708,15 @@ nfsd_rename(struct svc_rqst *rqstp, stru
 			goto out_dput_new;
 	}
 
-	host_err = -EXDEV;
-	if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
-		goto out_dput_new;
-	host_err = mnt_want_write(ffhp->fh_export->ex_path.mnt);
-	if (host_err)
-		goto out_dput_new;
-
-	host_err = vfs_rename(fdir, odentry, tdir, ndentry);
+	fh_to_path(ffhp, &old_dir_path);
+	fh_to_path(tfhp, &new_dir_path);
+	host_err = path_rename(&old_dir_path, odentry, &new_dir_path, ndentry);
 	if (!host_err && EX_ISSYNC(tfhp->fh_export)) {
 		host_err = nfsd_sync_dir(tdentry);
 		if (!host_err)
 			host_err = nfsd_sync_dir(fdentry);
 	}
 
-	mnt_drop_write(ffhp->fh_export->ex_path.mnt);
-
  out_dput_new:
 	dput(ndentry);
  out_dput_old:
Index: linux-2.6/include/linux/fs.h
===================================================================
--- linux-2.6.orig/include/linux/fs.h	2008-05-05 11:29:32.000000000 +0200
+++ linux-2.6/include/linux/fs.h	2008-05-05 11:29:32.000000000 +0200
@@ -1131,7 +1131,8 @@ extern int path_symlink(struct path *, s
 extern int path_link(struct dentry *, struct path *, struct dentry *);
 extern int path_rmdir(struct path *, struct dentry *);
 extern int path_unlink(struct path *, struct dentry *);
-extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);
+extern int path_rename(struct path *, struct dentry *,
+		       struct path *, struct dentry *);
 
 /*
  * VFS dentry helper functions.

--

[patch 08/10] vfs: add path_setattr()

[Miklos Szeredi]

[-- Attachment #1: path_setattr.patch --]
[-- Type: text/plain, Size: 9209 bytes --]

From: Miklos Szeredi <mszeredi@suse.cz>

Introduce path_setattr().  Stop exporting notify_change() to modules.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
---
 fs/attr.c           |   14 +++++++++++++-
 fs/ecryptfs/inode.c |   11 ++++++-----
 fs/nfsd/vfs.c       |   17 +++++++++++------
 fs/open.c           |   52 ++++++++++------------------------------------------
 fs/utimes.c         |    6 +-----
 include/linux/fs.h  |    1 +
 6 files changed, 42 insertions(+), 59 deletions(-)

Index: linux-2.6/fs/open.c
===================================================================
--- linux-2.6.orig/fs/open.c	2008-05-05 11:29:28.000000000 +0200
+++ linux-2.6/fs/open.c	2008-05-05 11:29:32.000000000 +0200
@@ -579,18 +579,13 @@ asmlinkage long sys_fchmod(unsigned int 
 
 	audit_inode(NULL, dentry);
 
-	err = mnt_want_write(file->f_path.mnt);
-	if (err)
-		goto out_putf;
 	mutex_lock(&inode->i_mutex);
 	if (mode == (mode_t) -1)
 		mode = inode->i_mode;
 	newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
 	newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
-	err = notify_change(dentry, &newattrs);
+	err = path_setattr(&file->f_path, &newattrs);
 	mutex_unlock(&inode->i_mutex);
-	mnt_drop_write(file->f_path.mnt);
-out_putf:
 	fput(file);
 out:
 	return err;
@@ -609,18 +604,13 @@ asmlinkage long sys_fchmodat(int dfd, co
 		goto out;
 	inode = nd.path.dentry->d_inode;
 
-	error = mnt_want_write(nd.path.mnt);
-	if (error)
-		goto dput_and_out;
 	mutex_lock(&inode->i_mutex);
 	if (mode == (mode_t) -1)
 		mode = inode->i_mode;
 	newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
 	newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
-	error = notify_change(nd.path.dentry, &newattrs);
+	error = path_setattr(&nd.path, &newattrs);
 	mutex_unlock(&inode->i_mutex);
-	mnt_drop_write(nd.path.mnt);
-dput_and_out:
 	path_put(&nd.path);
 out:
 	return error;
@@ -631,9 +621,9 @@ asmlinkage long sys_chmod(const char __u
 	return sys_fchmodat(AT_FDCWD, filename, mode);
 }
 
-static int chown_common(struct dentry * dentry, uid_t user, gid_t group)
+static int chown_common(struct path *path, uid_t user, gid_t group)
 {
-	struct inode *inode = dentry->d_inode;
+	struct inode *inode = path->dentry->d_inode;
 	int error;
 	struct iattr newattrs;
 
@@ -650,7 +640,7 @@ static int chown_common(struct dentry * 
 		newattrs.ia_valid |=
 			ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
 	mutex_lock(&inode->i_mutex);
-	error = notify_change(dentry, &newattrs);
+	error = path_setattr(path, &newattrs);
 	mutex_unlock(&inode->i_mutex);
 
 	return error;
@@ -664,12 +654,7 @@ asmlinkage long sys_chown(const char __u
 	error = user_path_walk(filename, &nd);
 	if (error)
 		goto out;
-	error = mnt_want_write(nd.path.mnt);
-	if (error)
-		goto out_release;
-	error = chown_common(nd.path.dentry, user, group);
-	mnt_drop_write(nd.path.mnt);
-out_release:
+	error = chown_common(&nd.path, user, group);
 	path_put(&nd.path);
 out:
 	return error;
@@ -689,12 +674,7 @@ asmlinkage long sys_fchownat(int dfd, co
 	error = __user_walk_fd(dfd, filename, follow, &nd);
 	if (error)
 		goto out;
-	error = mnt_want_write(nd.path.mnt);
-	if (error)
-		goto out_release;
-	error = chown_common(nd.path.dentry, user, group);
-	mnt_drop_write(nd.path.mnt);
-out_release:
+	error = chown_common(&nd.path, user, group);
 	path_put(&nd.path);
 out:
 	return error;
@@ -708,12 +688,7 @@ asmlinkage long sys_lchown(const char __
 	error = user_path_walk_link(filename, &nd);
 	if (error)
 		goto out;
-	error = mnt_want_write(nd.path.mnt);
-	if (error)
-		goto out_release;
-	error = chown_common(nd.path.dentry, user, group);
-	mnt_drop_write(nd.path.mnt);
-out_release:
+	error = chown_common(&nd.path, user, group);
 	path_put(&nd.path);
 out:
 	return error;
@@ -724,20 +699,13 @@ asmlinkage long sys_fchown(unsigned int 
 {
 	struct file * file;
 	int error = -EBADF;
-	struct dentry * dentry;
 
 	file = fget(fd);
 	if (!file)
 		goto out;
 
-	error = mnt_want_write(file->f_path.mnt);
-	if (error)
-		goto out_fput;
-	dentry = file->f_path.dentry;
-	audit_inode(NULL, dentry);
-	error = chown_common(dentry, user, group);
-	mnt_drop_write(file->f_path.mnt);
-out_fput:
+	audit_inode(NULL, file->f_path.dentry);
+	error = chown_common(&file->f_path, user, group);
 	fput(file);
 out:
 	return error;
Index: linux-2.6/fs/attr.c
===================================================================
--- linux-2.6.orig/fs/attr.c	2008-05-05 11:29:27.000000000 +0200
+++ linux-2.6/fs/attr.c	2008-05-05 11:29:32.000000000 +0200
@@ -14,6 +14,7 @@
 #include <linux/fcntl.h>
 #include <linux/quotaops.h>
 #include <linux/security.h>
+#include <linux/mount.h>
 
 /* Taken over from the old code... */
 
@@ -195,4 +196,15 @@ int notify_change(struct dentry * dentry
 	return error;
 }
 
-EXPORT_SYMBOL(notify_change);
+int path_setattr(struct path *path, struct iattr *attr)
+{
+	int error = mnt_want_write(path->mnt);
+
+	if (!error) {
+		error = notify_change(path->dentry, attr);
+		mnt_drop_write(path->mnt);
+	}
+
+	return error;
+}
+EXPORT_SYMBOL(path_setattr);
Index: linux-2.6/fs/nfsd/vfs.c
===================================================================
--- linux-2.6.orig/fs/nfsd/vfs.c	2008-05-05 11:29:32.000000000 +0200
+++ linux-2.6/fs/nfsd/vfs.c	2008-05-05 11:29:32.000000000 +0200
@@ -392,8 +392,11 @@ nfsd_setattr(struct svc_rqst *rqstp, str
 
 	err = nfserr_notsync;
 	if (!check_guard || guardtime == inode->i_ctime.tv_sec) {
+		struct path path;
+
 		fh_lock(fhp);
-		host_err = notify_change(dentry, iap);
+		fh_to_path(fhp, &path);
+		host_err = path_setattr(&path, iap);
 		err = nfserrno(host_err);
 		fh_unlock(fhp);
 	}
@@ -949,14 +952,16 @@ out:
 	return err;
 }
 
-static void kill_suid(struct dentry *dentry)
+static void kill_suid(struct svc_fh *fhp)
 {
+	struct path	path;
 	struct iattr	ia;
 	ia.ia_valid = ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
 
-	mutex_lock(&dentry->d_inode->i_mutex);
-	notify_change(dentry, &ia);
-	mutex_unlock(&dentry->d_inode->i_mutex);
+	mutex_lock(&path.dentry->d_inode->i_mutex);
+	fh_to_path(fhp, &path);
+	path_setattr(&path, &ia);
+	mutex_unlock(&path.dentry->d_inode->i_mutex);
 }
 
 static __be32
@@ -1014,7 +1019,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, s
 
 	/* clear setuid/setgid flag after write */
 	if (host_err >= 0 && (inode->i_mode & (S_ISUID | S_ISGID)))
-		kill_suid(dentry);
+		kill_suid(fhp);
 
 	if (host_err >= 0 && stable) {
 		static ino_t	last_ino;
Index: linux-2.6/include/linux/fs.h
===================================================================
--- linux-2.6.orig/include/linux/fs.h	2008-05-05 11:29:32.000000000 +0200
+++ linux-2.6/include/linux/fs.h	2008-05-05 11:29:32.000000000 +0200
@@ -1761,6 +1761,7 @@ extern int do_remount_sb(struct super_bl
 extern sector_t bmap(struct inode *, sector_t);
 #endif
 extern int notify_change(struct dentry *, struct iattr *);
+extern int path_setattr(struct path *, struct iattr *);
 extern int permission(struct inode *, int, struct nameidata *);
 extern int generic_permission(struct inode *, int,
 		int (*check_acl)(struct inode *, int));
Index: linux-2.6/fs/ecryptfs/inode.c
===================================================================
--- linux-2.6.orig/fs/ecryptfs/inode.c	2008-05-05 11:29:32.000000000 +0200
+++ linux-2.6/fs/ecryptfs/inode.c	2008-05-05 11:29:32.000000000 +0200
@@ -843,7 +843,7 @@ ecryptfs_permission(struct inode *inode,
 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 {
 	int rc = 0;
-	struct dentry *lower_dentry;
+	struct path lower_path;
 	struct inode *inode;
 	struct inode *lower_inode;
 	struct ecryptfs_crypt_stat *crypt_stat;
@@ -853,7 +853,8 @@ static int ecryptfs_setattr(struct dentr
 		ecryptfs_init_crypt_stat(crypt_stat);
 	inode = dentry->d_inode;
 	lower_inode = ecryptfs_inode_to_lower(inode);
-	lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	lower_path.mnt = ecryptfs_dentry_to_lower_mnt(dentry);
+	lower_path.dentry = ecryptfs_dentry_to_lower(dentry);
 	mutex_lock(&crypt_stat->cs_mutex);
 	if (S_ISDIR(dentry->d_inode->i_mode))
 		crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
@@ -904,9 +905,9 @@ static int ecryptfs_setattr(struct dentr
 	if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 		ia->ia_valid &= ~ATTR_MODE;
 
-	mutex_lock(&lower_dentry->d_inode->i_mutex);
-	rc = notify_change(lower_dentry, ia);
-	mutex_unlock(&lower_dentry->d_inode->i_mutex);
+	mutex_lock(&lower_path.dentry->d_inode->i_mutex);
+	rc = path_setattr(&lower_path, ia);
+	mutex_unlock(&lower_path.dentry->d_inode->i_mutex);
 out:
 	fsstack_copy_attr_all(inode, lower_inode, NULL);
 	return rc;
Index: linux-2.6/fs/utimes.c
===================================================================
--- linux-2.6.orig/fs/utimes.c	2008-05-05 11:29:28.000000000 +0200
+++ linux-2.6/fs/utimes.c	2008-05-05 11:29:32.000000000 +0200
@@ -78,11 +78,7 @@ static int utimes_common(struct path *pa
 		}
 	}
 	mutex_lock(&path->dentry->d_inode->i_mutex);
-	error = mnt_want_write(path->mnt);
-	if (!error) {
-		error = notify_change(path->dentry, &newattrs);
-		mnt_drop_write(path->mnt);
-	}
+	error = path_setattr(path, &newattrs);
 	mutex_unlock(&path->dentry->d_inode->i_mutex);
 
 	return error;

--

[patch 09/10] vfs: add path_setxattr()

[Miklos Szeredi]

[-- Attachment #1: path_setxattr.patch --]
[-- Type: text/plain, Size: 6486 bytes --]

From: Miklos Szeredi <mszeredi@suse.cz>

Introduce path_setxattr().  Make vfs_setxattr() static.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
---
 fs/nfsd/vfs.c         |   18 ++++++++++--------
 fs/xattr.c            |   44 ++++++++++++++++++++++----------------------
 include/linux/xattr.h |    3 ++-
 3 files changed, 34 insertions(+), 31 deletions(-)

Index: linux-2.6/fs/nfsd/vfs.c
===================================================================
--- linux-2.6.orig/fs/nfsd/vfs.c	2008-05-05 11:29:32.000000000 +0200
+++ linux-2.6/fs/nfsd/vfs.c	2008-05-05 11:29:33.000000000 +0200
@@ -434,7 +434,7 @@ static ssize_t nfsd_getxattr(struct dent
 
 #if defined(CONFIG_NFSD_V4)
 static int
-set_nfsv4_acl_one(struct dentry *dentry, struct posix_acl *pacl, char *key)
+set_nfsv4_acl_one(struct path *path, struct posix_acl *pacl, char *key)
 {
 	int len;
 	size_t buflen;
@@ -453,7 +453,7 @@ set_nfsv4_acl_one(struct dentry *dentry,
 		goto out;
 	}
 
-	error = vfs_setxattr(dentry, key, buf, len, 0);
+	error = path_setxattr(path, key, buf, len, 0);
 out:
 	kfree(buf);
 	return error;
@@ -465,7 +465,7 @@ nfsd4_set_nfs4_acl(struct svc_rqst *rqst
 {
 	__be32 error;
 	int host_error;
-	struct dentry *dentry;
+	struct path path;
 	struct inode *inode;
 	struct posix_acl *pacl = NULL, *dpacl = NULL;
 	unsigned int flags = 0;
@@ -475,8 +475,8 @@ nfsd4_set_nfs4_acl(struct svc_rqst *rqst
 	if (error)
 		return error;
 
-	dentry = fhp->fh_dentry;
-	inode = dentry->d_inode;
+	fh_to_path(fhp, &path);
+	inode = path.dentry->d_inode;
 	if (S_ISDIR(inode->i_mode))
 		flags = NFS4_ACL_DIR;
 
@@ -486,12 +486,12 @@ nfsd4_set_nfs4_acl(struct svc_rqst *rqst
 	} else if (host_error < 0)
 		goto out_nfserr;
 
-	host_error = set_nfsv4_acl_one(dentry, pacl, POSIX_ACL_XATTR_ACCESS);
+	host_error = set_nfsv4_acl_one(&path, pacl, POSIX_ACL_XATTR_ACCESS);
 	if (host_error < 0)
 		goto out_release;
 
 	if (S_ISDIR(inode->i_mode))
-		host_error = set_nfsv4_acl_one(dentry, dpacl, POSIX_ACL_XATTR_DEFAULT);
+		host_error = set_nfsv4_acl_one(&path, dpacl, POSIX_ACL_XATTR_DEFAULT);
 
 out_release:
 	posix_acl_release(pacl);
@@ -2038,6 +2038,7 @@ nfsd_get_posix_acl(struct svc_fh *fhp, i
 int
 nfsd_set_posix_acl(struct svc_fh *fhp, int type, struct posix_acl *acl)
 {
+	struct path path;
 	struct inode *inode = fhp->fh_dentry->d_inode;
 	char *name;
 	void *value = NULL;
@@ -2073,8 +2074,9 @@ nfsd_set_posix_acl(struct svc_fh *fhp, i
 	error = mnt_want_write(fhp->fh_export->ex_path.mnt);
 	if (error)
 		goto getout;
+	fh_to_path(fhp, &path);
 	if (size)
-		error = vfs_setxattr(fhp->fh_dentry, name, value, size, 0);
+		error = path_setxattr(&path, name, value, size, 0);
 	else {
 		if (!S_ISDIR(inode->i_mode) && type == ACL_TYPE_DEFAULT)
 			error = 0;
Index: linux-2.6/fs/xattr.c
===================================================================
--- linux-2.6.orig/fs/xattr.c	2008-05-05 11:28:37.000000000 +0200
+++ linux-2.6/fs/xattr.c	2008-05-05 11:29:33.000000000 +0200
@@ -66,7 +66,7 @@ xattr_permission(struct inode *inode, co
 	return permission(inode, mask, NULL);
 }
 
-int
+static int
 vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 		size_t size, int flags)
 {
@@ -101,7 +101,20 @@ out:
 	mutex_unlock(&inode->i_mutex);
 	return error;
 }
-EXPORT_SYMBOL_GPL(vfs_setxattr);
+
+int path_setxattr(struct path *path, const char *name, const void *value,
+		   size_t size, int flags)
+{
+	int error = mnt_want_write(path->mnt);
+
+	if (!error) {
+		error = vfs_setxattr(path->dentry, name, value, size, flags);
+		mnt_drop_write(path->mnt);
+	}
+
+	return error;
+}
+EXPORT_SYMBOL(path_setxattr);
 
 ssize_t
 xattr_getsecurity(struct inode *inode, const char *name, void *value,
@@ -218,7 +231,7 @@ EXPORT_SYMBOL_GPL(vfs_removexattr);
  * Extended attribute SET operations
  */
 static long
-setxattr(struct dentry *d, const char __user *name, const void __user *value,
+setxattr(struct path *path, const char __user *name, const void __user *value,
 	 size_t size, int flags)
 {
 	int error;
@@ -246,7 +259,7 @@ setxattr(struct dentry *d, const char __
 		}
 	}
 
-	error = vfs_setxattr(d, kname, kvalue, size, flags);
+	error = path_setxattr(path, kname, kvalue, size, flags);
 	kfree(kvalue);
 	return error;
 }
@@ -261,11 +274,8 @@ sys_setxattr(const char __user *path, co
 	error = user_path_walk(path, &nd);
 	if (error)
 		return error;
-	error = mnt_want_write(nd.path.mnt);
-	if (!error) {
-		error = setxattr(nd.path.dentry, name, value, size, flags);
-		mnt_drop_write(nd.path.mnt);
-	}
+
+	error = setxattr(&nd.path, name, value, size, flags);
 	path_put(&nd.path);
 	return error;
 }
@@ -280,11 +290,7 @@ sys_lsetxattr(const char __user *path, c
 	error = user_path_walk_link(path, &nd);
 	if (error)
 		return error;
-	error = mnt_want_write(nd.path.mnt);
-	if (!error) {
-		error = setxattr(nd.path.dentry, name, value, size, flags);
-		mnt_drop_write(nd.path.mnt);
-	}
+	error = setxattr(&nd.path, name, value, size, flags);
 	path_put(&nd.path);
 	return error;
 }
@@ -294,19 +300,13 @@ sys_fsetxattr(int fd, const char __user 
 	      size_t size, int flags)
 {
 	struct file *f;
-	struct dentry *dentry;
 	int error = -EBADF;
 
 	f = fget(fd);
 	if (!f)
 		return error;
-	dentry = f->f_path.dentry;
-	audit_inode(NULL, dentry);
-	error = mnt_want_write(f->f_path.mnt);
-	if (!error) {
-		error = setxattr(dentry, name, value, size, flags);
-		mnt_drop_write(f->f_path.mnt);
-	}
+	audit_inode(NULL, f->f_path.dentry);
+	error = setxattr(&f->f_path, name, value, size, flags);
 	fput(f);
 	return error;
 }
Index: linux-2.6/include/linux/xattr.h
===================================================================
--- linux-2.6.orig/include/linux/xattr.h	2008-05-05 11:28:37.000000000 +0200
+++ linux-2.6/include/linux/xattr.h	2008-05-05 11:29:33.000000000 +0200
@@ -35,6 +35,7 @@
 
 struct inode;
 struct dentry;
+struct path;
 
 struct xattr_handler {
 	char *prefix;
@@ -49,7 +50,7 @@ struct xattr_handler {
 ssize_t xattr_getsecurity(struct inode *, const char *, void *, size_t);
 ssize_t vfs_getxattr(struct dentry *, const char *, void *, size_t);
 ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
-int vfs_setxattr(struct dentry *, const char *, const void *, size_t, int);
+int path_setxattr(struct path *, const char *, const void *, size_t, int);
 int vfs_removexattr(struct dentry *, const char *);
 
 ssize_t generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size);

--

[patch 10/10] vfs: add path_removexattr()

[Miklos Szeredi]

[-- Attachment #1: path_removexattr.patch --]
[-- Type: text/plain, Size: 4607 bytes --]

From: Miklos Szeredi <mszeredi@suse.cz>

Introduce path_removexattr().  Make vfs_removexattr() static.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
---
 fs/nfsd/vfs.c         |    6 +-----
 fs/xattr.c            |   41 +++++++++++++++++++----------------------
 include/linux/xattr.h |    2 +-
 3 files changed, 21 insertions(+), 28 deletions(-)

Index: linux-2.6/fs/nfsd/vfs.c
===================================================================
--- linux-2.6.orig/fs/nfsd/vfs.c	2008-05-05 11:29:33.000000000 +0200
+++ linux-2.6/fs/nfsd/vfs.c	2008-05-05 11:29:33.000000000 +0200
@@ -2071,9 +2071,6 @@ nfsd_set_posix_acl(struct svc_fh *fhp, i
 	} else
 		size = 0;
 
-	error = mnt_want_write(fhp->fh_export->ex_path.mnt);
-	if (error)
-		goto getout;
 	fh_to_path(fhp, &path);
 	if (size)
 		error = path_setxattr(&path, name, value, size, 0);
@@ -2081,12 +2078,11 @@ nfsd_set_posix_acl(struct svc_fh *fhp, i
 		if (!S_ISDIR(inode->i_mode) && type == ACL_TYPE_DEFAULT)
 			error = 0;
 		else {
-			error = vfs_removexattr(fhp->fh_dentry, name);
+			error = path_removexattr(&path, name);
 			if (error == -ENODATA)
 				error = 0;
 		}
 	}
-	mnt_drop_write(fhp->fh_export->ex_path.mnt);
 
 getout:
 	kfree(value);
Index: linux-2.6/fs/xattr.c
===================================================================
--- linux-2.6.orig/fs/xattr.c	2008-05-05 11:29:33.000000000 +0200
+++ linux-2.6/fs/xattr.c	2008-05-05 11:29:33.000000000 +0200
@@ -199,7 +199,7 @@ vfs_listxattr(struct dentry *d, char *li
 }
 EXPORT_SYMBOL_GPL(vfs_listxattr);
 
-int
+static int
 vfs_removexattr(struct dentry *dentry, const char *name)
 {
 	struct inode *inode = dentry->d_inode;
@@ -224,8 +224,19 @@ vfs_removexattr(struct dentry *dentry, c
 		fsnotify_xattr(dentry);
 	return error;
 }
-EXPORT_SYMBOL_GPL(vfs_removexattr);
 
+int path_removexattr(struct path *path, const char *name)
+{
+	int error = mnt_want_write(path->mnt);
+
+	if (!error) {
+		error = vfs_removexattr(path->dentry, name);
+		mnt_drop_write(path->mnt);
+	}
+
+	return error;
+}
+EXPORT_SYMBOL(path_removexattr);
 
 /*
  * Extended attribute SET operations
@@ -471,7 +482,7 @@ sys_flistxattr(int fd, char __user *list
  * Extended attribute REMOVE operations
  */
 static long
-removexattr(struct dentry *d, const char __user *name)
+removexattr(struct path *path, const char __user *name)
 {
 	int error;
 	char kname[XATTR_NAME_MAX + 1];
@@ -482,7 +493,7 @@ removexattr(struct dentry *d, const char
 	if (error < 0)
 		return error;
 
-	return vfs_removexattr(d, kname);
+	return path_removexattr(path, kname);
 }
 
 asmlinkage long
@@ -494,11 +505,7 @@ sys_removexattr(const char __user *path,
 	error = user_path_walk(path, &nd);
 	if (error)
 		return error;
-	error = mnt_want_write(nd.path.mnt);
-	if (!error) {
-		error = removexattr(nd.path.dentry, name);
-		mnt_drop_write(nd.path.mnt);
-	}
+	error = removexattr(&nd.path, name);
 	path_put(&nd.path);
 	return error;
 }
@@ -512,11 +519,7 @@ sys_lremovexattr(const char __user *path
 	error = user_path_walk_link(path, &nd);
 	if (error)
 		return error;
-	error = mnt_want_write(nd.path.mnt);
-	if (!error) {
-		error = removexattr(nd.path.dentry, name);
-		mnt_drop_write(nd.path.mnt);
-	}
+	error = removexattr(&nd.path, name);
 	path_put(&nd.path);
 	return error;
 }
@@ -525,19 +528,13 @@ asmlinkage long
 sys_fremovexattr(int fd, const char __user *name)
 {
 	struct file *f;
-	struct dentry *dentry;
 	int error = -EBADF;
 
 	f = fget(fd);
 	if (!f)
 		return error;
-	dentry = f->f_path.dentry;
-	audit_inode(NULL, dentry);
-	error = mnt_want_write(f->f_path.mnt);
-	if (!error) {
-		error = removexattr(dentry, name);
-		mnt_drop_write(f->f_path.mnt);
-	}
+	audit_inode(NULL, f->f_path.dentry);
+	error = removexattr(&f->f_path, name);
 	fput(f);
 	return error;
 }
Index: linux-2.6/include/linux/xattr.h
===================================================================
--- linux-2.6.orig/include/linux/xattr.h	2008-05-05 11:29:33.000000000 +0200
+++ linux-2.6/include/linux/xattr.h	2008-05-05 11:29:33.000000000 +0200
@@ -51,7 +51,7 @@ ssize_t xattr_getsecurity(struct inode *
 ssize_t vfs_getxattr(struct dentry *, const char *, void *, size_t);
 ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
 int path_setxattr(struct path *, const char *, const void *, size_t, int);
-int vfs_removexattr(struct dentry *, const char *);
+int path_removexattr(struct path *, const char *);
 
 ssize_t generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size);
 ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);

--

Re: [patch 01/10] vfs: add path_create() and path_mknod()

[Andrew Morton]

On Mon, 05 May 2008 12:16:22 +0200 Miklos Szeredi <miklos@szeredi.hu> wrote:

> R/O bind mounts require operations which modify the filesystem to be
> wrapped in mnt_want_write()/mnt_drop_write().  Create helpers which do
> this, so callers won't need to bother, and more importantly, cannot
> forget!  Call these path_*, analogous to vfs_*.  Since there are no
> callers of vfs_* left, make them static.

ooh, yum.  This appears to address my main complaint about the r-o-bind-mount
stuff: fragility.

> Overall this patchset is just 23 lines in the red, but at the same
> time it fixes several places in nfsd and the whole of ecryptfs, where
> the mnt_want_write/drop_write() calls were missing.

Yeah, like that.

Re: [patch 01/10] vfs: add path_create() and path_mknod()

[Al Viro]

On Mon, May 05, 2008 at 09:12:51PM -0700, Andrew Morton wrote:
> On Mon, 05 May 2008 12:16:22 +0200 Miklos Szeredi <miklos@szeredi.hu> wrote:
> 
> > R/O bind mounts require operations which modify the filesystem to be
> > wrapped in mnt_want_write()/mnt_drop_write().  Create helpers which do
> > this, so callers won't need to bother, and more importantly, cannot
> > forget!  Call these path_*, analogous to vfs_*.  Since there are no
> > callers of vfs_* left, make them static.
> 
> ooh, yum.  This appears to address my main complaint about the r-o-bind-mount
> stuff: fragility.
> 
> > Overall this patchset is just 23 lines in the red, but at the same
> > time it fixes several places in nfsd and the whole of ecryptfs, where
> > the mnt_want_write/drop_write() calls were missing.
> 
> Yeah, like that.

Except that it fixes nothing in nfsd, as we'd already figured out and
"solution" for ecryptfs is more than slightly dubious.  Not that nfsd
one wasn't...

While we are at it, I call bullshit on "make vfs_...() static" and I suspect
that Miklos won't be happy with it once he cares to think through just how
little is going to be guaranteed about those vfsmounts.  As in "not promised
to be attached anywhere", for starters...

Re: [patch 01/10] vfs: add path_create() and path_mknod()

[Andrew Morton]

On Tue, 6 May 2008 05:24:26 +0100 Al Viro <viro@ZenIV.linux.org.uk> wrote:

> On Mon, May 05, 2008 at 09:12:51PM -0700, Andrew Morton wrote:
> > On Mon, 05 May 2008 12:16:22 +0200 Miklos Szeredi <miklos@szeredi.hu> wrote:
> > 
> > > R/O bind mounts require operations which modify the filesystem to be
> > > wrapped in mnt_want_write()/mnt_drop_write().  Create helpers which do
> > > this, so callers won't need to bother, and more importantly, cannot
> > > forget!  Call these path_*, analogous to vfs_*.  Since there are no
> > > callers of vfs_* left, make them static.
> > 
> > ooh, yum.  This appears to address my main complaint about the r-o-bind-mount
> > stuff: fragility.
> > 
> > > Overall this patchset is just 23 lines in the red, but at the same
> > > time it fixes several places in nfsd and the whole of ecryptfs, where
> > > the mnt_want_write/drop_write() calls were missing.
> > 
> > Yeah, like that.
> 
> Except that it fixes nothing in nfsd, as we'd already figured out and
> "solution" for ecryptfs is more than slightly dubious.  Not that nfsd
> one wasn't...

Well OK.  But those open-coded mnt_want_write() calls all over the place
still stink.

Re: [patch 01/10] vfs: add path_create() and path_mknod()

[Miklos Szeredi]

> > > R/O bind mounts require operations which modify the filesystem to be
> > > wrapped in mnt_want_write()/mnt_drop_write().  Create helpers which do
> > > this, so callers won't need to bother, and more importantly, cannot
> > > forget!  Call these path_*, analogous to vfs_*.  Since there are no
> > > callers of vfs_* left, make them static.
> > 
> > ooh, yum.  This appears to address my main complaint about the
> > r-o-bind-mount stuff: fragility.
> > 
> > > Overall this patchset is just 23 lines in the red, but at the same
> > > time it fixes several places in nfsd and the whole of ecryptfs, where
> > > the mnt_want_write/drop_write() calls were missing.
> > 
> > Yeah, like that.
> 
> Except that it fixes nothing in nfsd, as we'd already figured out

Oh, it does!  It fixes at least one race, where nfsd is checking for
r/o mounts but is not keeping the mount from being marked r/o during
the operation.

I also suspect it fixes more than that, that we all just missed when
going over the callers of vfs_*().

> and
> "solution" for ecryptfs is more than slightly dubious.  Not that nfsd
> one wasn't...
> 
> While we are at it, I call bullshit on "make vfs_...() static" and I suspect
> that Miklos won't be happy with it once he cares to think through just how
> little is going to be guaranteed about those vfsmounts.  As in "not promised
> to be attached anywhere", for starters...

How does attachment figure into being marked r/o?  Or into anyting
else, for that matter: no path looked up is ever guaranteed to be
attached, and we've been getting along fine with that.

Al, I've thought this over very well, and it seems to me that you've
just been trying to find excuses.  Which is OK, I guess: that's what
review is about.  But at some point we shouold really just move on.

Miklos

[patch 08/10] vfs: add path_setattr()

[Miklos Szeredi]

[-- Attachment #1: path_setattr.patch --]
[-- Type: text/plain, Size: 9278 bytes --]

From: Miklos Szeredi <mszeredi@suse.cz>

Introduce path_setattr().  Add checks to IS_IMMUTABLE(inode) and
IS_APPEND(inode) since all callers require it.  Maybe these should be
moved into notify_change()?

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
---
 fs/attr.c           |   23 ++++++++++++++++-
 fs/ecryptfs/inode.c |   11 ++++----
 fs/nfsd/vfs.c       |   21 +++++++++++-----
 fs/open.c           |   68 ++++++----------------------------------------------
 include/linux/fs.h  |    1 
 5 files changed, 53 insertions(+), 71 deletions(-)

Index: vfs-2.6/fs/open.c
===================================================================
--- vfs-2.6.orig/fs/open.c	2008-04-02 21:10:13.000000000 +0200
+++ vfs-2.6/fs/open.c	2008-04-02 21:41:21.000000000 +0200
@@ -578,23 +578,13 @@ asmlinkage long sys_fchmod(unsigned int 
 
 	audit_inode(NULL, dentry);
 
-	err = mnt_want_write(file->f_vfsmnt);
-	if (err)
-		goto out_putf;
-	err = -EPERM;
-	if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
-		goto out_drop_write;
 	mutex_lock(&inode->i_mutex);
 	if (mode == (mode_t) -1)
 		mode = inode->i_mode;
 	newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
 	newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
-	err = notify_change(dentry, &newattrs);
+	err = path_setattr(&file->f_path, &newattrs);
 	mutex_unlock(&inode->i_mutex);
-
-out_drop_write:
-	mnt_drop_write(file->f_vfsmnt);
-out_putf:
 	fput(file);
 out:
 	return err;
@@ -613,25 +603,14 @@ asmlinkage long sys_fchmodat(int dfd, co
 		goto out;
 	inode = nd.path.dentry->d_inode;
 
-	error = mnt_want_write(nd.path.mnt);
-	if (error)
-		goto dput_and_out;
-
-	error = -EPERM;
-	if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
-		goto out_drop_write;
-
 	mutex_lock(&inode->i_mutex);
 	if (mode == (mode_t) -1)
 		mode = inode->i_mode;
 	newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
 	newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
-	error = notify_change(nd.path.dentry, &newattrs);
+	error = path_setattr(&nd.path, &newattrs);
 	mutex_unlock(&inode->i_mutex);
 
-out_drop_write:
-	mnt_drop_write(nd.path.mnt);
-dput_and_out:
 	path_put(&nd.path);
 out:
 	return error;
@@ -642,20 +621,12 @@ asmlinkage long sys_chmod(const char __u
 	return sys_fchmodat(AT_FDCWD, filename, mode);
 }
 
-static int chown_common(struct dentry * dentry, uid_t user, gid_t group)
+static int chown_common(struct path *path, uid_t user, gid_t group)
 {
-	struct inode * inode;
+	struct inode *inode = path->dentry->d_inode;
 	int error;
 	struct iattr newattrs;
 
-	error = -ENOENT;
-	if (!(inode = dentry->d_inode)) {
-		printk(KERN_ERR "chown_common: NULL inode\n");
-		goto out;
-	}
-	error = -EPERM;
-	if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
-		goto out;
 	newattrs.ia_valid =  ATTR_CTIME;
 	if (user != (uid_t) -1) {
 		newattrs.ia_valid |= ATTR_UID;
@@ -669,9 +640,8 @@ static int chown_common(struct dentry * 
 		newattrs.ia_valid |=
 			ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
 	mutex_lock(&inode->i_mutex);
-	error = notify_change(dentry, &newattrs);
+	error = path_setattr(path, &newattrs);
 	mutex_unlock(&inode->i_mutex);
-out:
 	return error;
 }
 
@@ -683,12 +653,7 @@ asmlinkage long sys_chown(const char __u
 	error = user_path_walk(filename, &nd);
 	if (error)
 		goto out;
-	error = mnt_want_write(nd.path.mnt);
-	if (error)
-		goto out_release;
-	error = chown_common(nd.path.dentry, user, group);
-	mnt_drop_write(nd.path.mnt);
-out_release:
+	error = chown_common(&nd.path, user, group);
 	path_put(&nd.path);
 out:
 	return error;
@@ -708,12 +673,7 @@ asmlinkage long sys_fchownat(int dfd, co
 	error = __user_walk_fd(dfd, filename, follow, &nd);
 	if (error)
 		goto out;
-	error = mnt_want_write(nd.path.mnt);
-	if (error)
-		goto out_release;
-	error = chown_common(nd.path.dentry, user, group);
-	mnt_drop_write(nd.path.mnt);
-out_release:
+	error = chown_common(&nd.path, user, group);
 	path_put(&nd.path);
 out:
 	return error;
@@ -727,12 +687,7 @@ asmlinkage long sys_lchown(const char __
 	error = user_path_walk_link(filename, &nd);
 	if (error)
 		goto out;
-	error = mnt_want_write(nd.path.mnt);
-	if (error)
-		goto out_release;
-	error = chown_common(nd.path.dentry, user, group);
-	mnt_drop_write(nd.path.mnt);
-out_release:
+	error = chown_common(&nd.path, user, group);
 	path_put(&nd.path);
 out:
 	return error;
@@ -749,14 +704,9 @@ asmlinkage long sys_fchown(unsigned int 
 	if (!file)
 		goto out;
 
-	error = mnt_want_write(file->f_vfsmnt);
-	if (error)
-		goto out_fput;
 	dentry = file->f_path.dentry;
 	audit_inode(NULL, dentry);
-	error = chown_common(dentry, user, group);
-	mnt_drop_write(file->f_vfsmnt);
-out_fput:
+	error = chown_common(&file->f_path, user, group);
 	fput(file);
 out:
 	return error;
Index: vfs-2.6/fs/attr.c
===================================================================
--- vfs-2.6.orig/fs/attr.c	2008-04-02 21:10:13.000000000 +0200
+++ vfs-2.6/fs/attr.c	2008-04-02 21:41:21.000000000 +0200
@@ -14,6 +14,7 @@
 #include <linux/fcntl.h>
 #include <linux/quotaops.h>
 #include <linux/security.h>
+#include <linux/mount.h>
 
 /* Taken over from the old code... */
 
@@ -182,5 +183,25 @@ int notify_change(struct dentry * dentry
 
 	return error;
 }
-
 EXPORT_SYMBOL(notify_change);
+
+int path_setattr(struct path *path, struct iattr *attr)
+{
+	struct inode *inode = path->dentry->d_inode;
+	int error = mnt_want_write(path->mnt);
+
+	if (error)
+		goto out;
+
+	error = -EPERM;
+	if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
+		goto out_drop_write;
+
+	error = notify_change(path->dentry, attr);
+
+ out_drop_write:
+	mnt_drop_write(path->mnt);
+ out:
+	return error;
+}
+EXPORT_SYMBOL(path_setattr);
Index: vfs-2.6/fs/nfsd/vfs.c
===================================================================
--- vfs-2.6.orig/fs/nfsd/vfs.c	2008-04-02 21:37:52.000000000 +0200
+++ vfs-2.6/fs/nfsd/vfs.c	2008-04-02 21:41:21.000000000 +0200
@@ -387,8 +387,13 @@ nfsd_setattr(struct svc_rqst *rqstp, str
 
 	err = nfserr_notsync;
 	if (!check_guard || guardtime == inode->i_ctime.tv_sec) {
+		struct path path = {
+			.mnt = fhp->fh_export->ex_path.mnt,
+			.dentry = dentry,
+		};
+
 		fh_lock(fhp);
-		host_err = notify_change(dentry, iap);
+		host_err = path_setattr(&path, iap);
 		err = nfserrno(host_err);
 		fh_unlock(fhp);
 	}
@@ -944,14 +949,18 @@ out:
 	return err;
 }
 
-static void kill_suid(struct dentry *dentry)
+static void kill_suid(struct svc_fh *fhp)
 {
+	struct path path = {
+		.mnt = fhp->fh_export->ex_path.mnt,
+		.dentry = fhp->fh_dentry,
+	};
 	struct iattr	ia;
 	ia.ia_valid = ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
 
-	mutex_lock(&dentry->d_inode->i_mutex);
-	notify_change(dentry, &ia);
-	mutex_unlock(&dentry->d_inode->i_mutex);
+	mutex_lock(&path.dentry->d_inode->i_mutex);
+	path_setattr(&path, &ia);
+	mutex_unlock(&path.dentry->d_inode->i_mutex);
 }
 
 static __be32
@@ -1009,7 +1018,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, s
 
 	/* clear setuid/setgid flag after write */
 	if (host_err >= 0 && (inode->i_mode & (S_ISUID | S_ISGID)))
-		kill_suid(dentry);
+		kill_suid(fhp);
 
 	if (host_err >= 0 && stable) {
 		static ino_t	last_ino;
Index: vfs-2.6/include/linux/fs.h
===================================================================
--- vfs-2.6.orig/include/linux/fs.h	2008-04-02 21:37:52.000000000 +0200
+++ vfs-2.6/include/linux/fs.h	2008-04-02 21:41:21.000000000 +0200
@@ -1760,6 +1760,7 @@ extern int do_remount_sb(struct super_bl
 extern sector_t bmap(struct inode *, sector_t);
 #endif
 extern int notify_change(struct dentry *, struct iattr *);
+extern int path_setattr(struct path *, struct iattr *);
 extern int permission(struct inode *, int, struct nameidata *);
 extern int generic_permission(struct inode *, int,
 		int (*check_acl)(struct inode *, int));
Index: vfs-2.6/fs/ecryptfs/inode.c
===================================================================
--- vfs-2.6.orig/fs/ecryptfs/inode.c	2008-04-02 21:37:52.000000000 +0200
+++ vfs-2.6/fs/ecryptfs/inode.c	2008-04-02 21:41:21.000000000 +0200
@@ -846,7 +846,7 @@ ecryptfs_permission(struct inode *inode,
 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 {
 	int rc = 0;
-	struct dentry *lower_dentry;
+	struct path lower_path;
 	struct inode *inode;
 	struct inode *lower_inode;
 	struct ecryptfs_crypt_stat *crypt_stat;
@@ -856,7 +856,8 @@ static int ecryptfs_setattr(struct dentr
 		ecryptfs_init_crypt_stat(crypt_stat);
 	inode = dentry->d_inode;
 	lower_inode = ecryptfs_inode_to_lower(inode);
-	lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	lower_path.mnt = ecryptfs_dentry_to_lower_mnt(dentry);
+	lower_path.dentry = ecryptfs_dentry_to_lower(dentry);
 	mutex_lock(&crypt_stat->cs_mutex);
 	if (S_ISDIR(dentry->d_inode->i_mode))
 		crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
@@ -907,9 +908,9 @@ static int ecryptfs_setattr(struct dentr
 	if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 		ia->ia_valid &= ~ATTR_MODE;
 
-	mutex_lock(&lower_dentry->d_inode->i_mutex);
-	rc = notify_change(lower_dentry, ia);
-	mutex_unlock(&lower_dentry->d_inode->i_mutex);
+	mutex_lock(&lower_path.dentry->d_inode->i_mutex);
+	rc = path_setattr(&lower_path, ia);
+	mutex_unlock(&lower_path.dentry->d_inode->i_mutex);
 out:
 	fsstack_copy_attr_all(inode, lower_inode, NULL);
 	return rc;

--