[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>
diff --git a/fs/smbfs/proto.h b/fs/smbfs/proto.h
index 4766459..972ed7d 100644
--- a/fs/smbfs/proto.h
+++ b/fs/smbfs/proto.h
@@ -29,7 +29,7 @@
 extern int smb_proc_setattr(struct dentry *dir, struct smb_fattr *fattr);
 extern int smb_proc_setattr_unix(struct dentry *d, struct iattr *attr, unsigned int major, unsigned int minor);
 extern int smb_proc_settime(struct dentry *dentry, struct smb_fattr *fattr);
-extern int smb_proc_dskattr(struct super_block *sb, struct kstatfs *attr);
+extern int smb_proc_dskattr(struct dentry *dentry, struct kstatfs *attr);
 extern int smb_proc_read_link(struct smb_sb_info *server, struct dentry *d, char *buffer, int len);
 extern int smb_proc_symlink(struct smb_sb_info *server, struct dentry *d, const char *oldpath);
 extern int smb_proc_link(struct smb_sb_info *server, struct dentry *dentry, struct dentry *new_dentry);