[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/include/linux/fs.h b/include/linux/fs.h
index 3e50dd24af87..c823a3815e24 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1096,7 +1096,7 @@ struct super_operations {
         int (*sync_fs)(struct super_block *sb, int wait);
         void (*write_super_lockfs) (struct super_block *);
         void (*unlockfs) (struct super_block *);
-        int (*statfs) (struct super_block *, struct kstatfs *);
+        int (*statfs) (struct dentry *, struct kstatfs *);
         int (*remount_fs) (struct super_block *, int *, char *);
         void (*clear_inode) (struct inode *);
         void (*umount_begin) (struct super_block *);
@@ -1325,7 +1325,7 @@ extern struct vfsmount *copy_tree(struct vfsmount *, struct dentry *, int);
 extern void mnt_set_mountpoint(struct vfsmount *, struct dentry *,
                                   struct vfsmount *);
 
-extern int vfs_statfs(struct super_block *, struct kstatfs *);
+extern int vfs_statfs(struct dentry *, struct kstatfs *);
 
 /* /sys/fs */
 extern struct subsystem fs_subsys;
@@ -1746,7 +1746,7 @@ extern int dcache_dir_close(struct inode *, struct file *);
 extern loff_t dcache_dir_lseek(struct file *, loff_t, int);
 extern int dcache_readdir(struct file *, void *, filldir_t);
 extern int simple_getattr(struct vfsmount *, struct dentry *, struct kstat *);
-extern int simple_statfs(struct super_block *, struct kstatfs *);
+extern int simple_statfs(struct dentry *, struct kstatfs *);
 extern int simple_link(struct dentry *, struct inode *, struct dentry *);
 extern int simple_unlink(struct inode *, struct dentry *);
 extern int simple_rmdir(struct inode *, struct dentry *);