[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, 2 insertions, 2 deletions

diff --git a/fs/romfs/inode.c b/fs/romfs/inode.c
index 4d6cd6621062..283fbc6b8eea 100644
--- a/fs/romfs/inode.c
+++ b/fs/romfs/inode.c
@@ -179,12 +179,12 @@ outnobh:
 /* That's simple too. */
 
 static int
-romfs_statfs(struct super_block *sb, struct kstatfs *buf)
+romfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
         buf->f_type = ROMFS_MAGIC;
         buf->f_bsize = ROMBSIZE;
         buf->f_bfree = buf->f_bavail = buf->f_ffree;
-        buf->f_blocks = (romfs_maxsize(sb)+ROMBSIZE-1)>>ROMBSBITS;
+        buf->f_blocks = (romfs_maxsize(dentry->d_sb)+ROMBSIZE-1)>>ROMBSBITS;
         buf->f_namelen = ROMFS_MAXFN;
         return 0;
 }