[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>

2 files changed, 3 insertions, 3 deletions

diff --git a/fs/jffs2/fs.c b/fs/jffs2/fs.c
index 7b6c24b14f85..2900ec3ec3af 100644
--- a/fs/jffs2/fs.c
+++ b/fs/jffs2/fs.c
@@ -192,9 +192,9 @@ int jffs2_setattr(struct dentry *dentry, struct iattr *iattr)
         return rc;
 }
 
-int jffs2_statfs(struct super_block *sb, struct kstatfs *buf)
+int jffs2_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
-        struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
+        struct jffs2_sb_info *c = JFFS2_SB_INFO(dentry->d_sb);
         unsigned long avail;
 
         buf->f_type = JFFS2_SUPER_MAGIC;
diff --git a/fs/jffs2/os-linux.h b/fs/jffs2/os-linux.h
index cd4021bcb944..6b5223565405 100644
--- a/fs/jffs2/os-linux.h
+++ b/fs/jffs2/os-linux.h
@@ -175,7 +175,7 @@ void jffs2_clear_inode (struct inode *);
 void jffs2_dirty_inode(struct inode *inode);
 struct inode *jffs2_new_inode (struct inode *dir_i, int mode,
                                struct jffs2_raw_inode *ri);
-int jffs2_statfs (struct super_block *, struct kstatfs *);
+int jffs2_statfs (struct dentry *, struct kstatfs *);
 void jffs2_write_super (struct super_block *);
 int jffs2_remount_fs (struct super_block *, int *, char *);
 int jffs2_do_fill_super(struct super_block *sb, void *data, int silent);