[PATCH] VFS: Permit filesystem to perform statfs with a known root dentry

Give the statfs superblock operation a dentry pointer rather than a superblock
pointer.

This complements the get_sb() patch.  That reduced the significance of
sb->s_root, allowing NFS to place a fake root there.  However, NFS does
require a dentry to use as a target for the statfs operation.  This permits
the root in the vfsmount to be used instead.

linux/mount.h has been added where necessary to make allyesconfig build
successfully.

Interest has also been expressed for use with the FUSE and XFS filesystems.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Nathan Scott <nathans@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/fs/compat.c b/fs/compat.c
index b1f64786a613..7e7e5bc4f3cf 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -197,7 +197,7 @@ asmlinkage long compat_sys_statfs(const char __user *path, struct compat_statfs
         error = user_path_walk(path, &nd);
         if (!error) {
                 struct kstatfs tmp;
-                error = vfs_statfs(nd.dentry->d_inode->i_sb, &tmp);
+                error = vfs_statfs(nd.dentry, &tmp);
                 if (!error)
                         error = put_compat_statfs(buf, &tmp);
                 path_release(&nd);
@@ -215,7 +215,7 @@ asmlinkage long compat_sys_fstatfs(unsigned int fd, struct compat_statfs __user
         file = fget(fd);
         if (!file)
                 goto out;
-        error = vfs_statfs(file->f_dentry->d_inode->i_sb, &tmp);
+        error = vfs_statfs(file->f_dentry, &tmp);
         if (!error)
                 error = put_compat_statfs(buf, &tmp);
         fput(file);
@@ -265,7 +265,7 @@ asmlinkage long compat_sys_statfs64(const char __user *path, compat_size_t sz, s
         error = user_path_walk(path, &nd);
         if (!error) {
                 struct kstatfs tmp;
-                error = vfs_statfs(nd.dentry->d_inode->i_sb, &tmp);
+                error = vfs_statfs(nd.dentry, &tmp);
                 if (!error)
                         error = put_compat_statfs64(buf, &tmp);
                 path_release(&nd);
@@ -286,7 +286,7 @@ asmlinkage long compat_sys_fstatfs64(unsigned int fd, compat_size_t sz, struct c
         file = fget(fd);
         if (!file)
                 goto out;
-        error = vfs_statfs(file->f_dentry->d_inode->i_sb, &tmp);
+        error = vfs_statfs(file->f_dentry, &tmp);
         if (!error)
                 error = put_compat_statfs64(buf, &tmp);
         fput(file);