[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/reiserfs/super.c b/fs/reiserfs/super.c
index f3ff41d33989..00f1321e9209 100644
--- a/fs/reiserfs/super.c
+++ b/fs/reiserfs/super.c
@@ -60,7 +60,7 @@ static int is_any_reiserfs_magic_string(struct reiserfs_super_block *rs)
 }
 
 static int reiserfs_remount(struct super_block *s, int *flags, char *data);
-static int reiserfs_statfs(struct super_block *s, struct kstatfs *buf);
+static int reiserfs_statfs(struct dentry *dentry, struct kstatfs *buf);
 
 static int reiserfs_sync_fs(struct super_block *s, int wait)
 {
@@ -1938,15 +1938,15 @@ static int reiserfs_fill_super(struct super_block *s, void *data, int silent)
         return errval;
 }
 
-static int reiserfs_statfs(struct super_block *s, struct kstatfs *buf)
+static int reiserfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
-        struct reiserfs_super_block *rs = SB_DISK_SUPER_BLOCK(s);
+        struct reiserfs_super_block *rs = SB_DISK_SUPER_BLOCK(dentry->d_sb);
 
         buf->f_namelen = (REISERFS_MAX_NAME(s->s_blocksize));
         buf->f_bfree = sb_free_blocks(rs);
         buf->f_bavail = buf->f_bfree;
         buf->f_blocks = sb_block_count(rs) - sb_bmap_nr(rs) - 1;
-        buf->f_bsize = s->s_blocksize;
+        buf->f_bsize = dentry->d_sb->s_blocksize;
         /* changed to accommodate gcc folks. */
         buf->f_type = REISERFS_SUPER_MAGIC;
         return 0;