[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, 3 insertions, 3 deletions

diff --git a/fs/efs/super.c b/fs/efs/super.c
index 1ba5e14f879f..8ac2462ae5dd 100644
--- a/fs/efs/super.c
+++ b/fs/efs/super.c
@@ -15,7 +15,7 @@
 #include <linux/buffer_head.h>
 #include <linux/vfs.h>
 
-static int efs_statfs(struct super_block *s, struct kstatfs *buf);
+static int efs_statfs(struct dentry *dentry, struct kstatfs *buf);
 static int efs_fill_super(struct super_block *s, void *d, int silent);
 
 static int efs_get_sb(struct file_system_type *fs_type,
@@ -322,8 +322,8 @@ out_no_fs:
         return -EINVAL;
 }
 
-static int efs_statfs(struct super_block *s, struct kstatfs *buf) {
-        struct efs_sb_info *sb = SUPER_INFO(s);
+static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
+        struct efs_sb_info *sb = SUPER_INFO(dentry->d_sb);
 
         buf->f_type    = EFS_SUPER_MAGIC;       /* efs magic number */
         buf->f_bsize   = EFS_BLOCKSIZE;         /* blocksize */