[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, 2 deletions

diff --git a/fs/ncpfs/inode.c b/fs/ncpfs/inode.c
index 8db033fab3fd..90d2ea28f333 100644
--- a/fs/ncpfs/inode.c
+++ b/fs/ncpfs/inode.c
@@ -39,7 +39,7 @@
 
 static void ncp_delete_inode(struct inode *);
 static void ncp_put_super(struct super_block *);
-static int  ncp_statfs(struct super_block *, struct kstatfs *);
+static int  ncp_statfs(struct dentry *, struct kstatfs *);
 
 static kmem_cache_t * ncp_inode_cachep;
 
@@ -724,13 +724,14 @@ static void ncp_put_super(struct super_block *sb)
         kfree(server);
 }
 
-static int ncp_statfs(struct super_block *sb, struct kstatfs *buf)
+static int ncp_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
         struct dentry* d;
         struct inode* i;
         struct ncp_inode_info* ni;
         struct ncp_server* s;
         struct ncp_volume_info vi;
+        struct super_block *sb = dentry->d_sb;
         int err;
         __u8 dh;