[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, 5 insertions, 5 deletions

diff --git a/fs/minix/inode.c b/fs/minix/inode.c
index 14f24dfbfe30..a6fb509b7341 100644
--- a/fs/minix/inode.c
+++ b/fs/minix/inode.c
@@ -19,7 +19,7 @@
 
 static void minix_read_inode(struct inode * inode);
 static int minix_write_inode(struct inode * inode, int wait);
-static int minix_statfs(struct super_block *sb, struct kstatfs *buf);
+static int minix_statfs(struct dentry *dentry, struct kstatfs *buf);
 static int minix_remount (struct super_block * sb, int * flags, char * data);
 
 static void minix_delete_inode(struct inode *inode)
@@ -296,11 +296,11 @@ out_bad_sb:
         return -EINVAL;
 }
 
-static int minix_statfs(struct super_block *sb, struct kstatfs *buf)
+static int minix_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
-        struct minix_sb_info *sbi = minix_sb(sb);
-        buf->f_type = sb->s_magic;
-        buf->f_bsize = sb->s_blocksize;
+        struct minix_sb_info *sbi = minix_sb(dentry->d_sb);
+        buf->f_type = dentry->d_sb->s_magic;
+        buf->f_bsize = dentry->d_sb->s_blocksize;
         buf->f_blocks = (sbi->s_nzones - sbi->s_firstdatazone) << sbi->s_log_zone_size;
         buf->f_bfree = minix_count_free_blocks(sbi);
         buf->f_bavail = buf->f_bfree;