[PATCH 3.17 69/73] btrfs: fix wrong accounting of raid1 data profile in statfs

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

3.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Sterba <dsterba@suse.cz>

commit 0d95c1bec906dd1ad951c9c001e798ca52baeb0f upstream.

The sizes that are obtained from space infos are in raw units and have
to be adjusted according to the raid factor. This was missing for
f_bavail and df reported doubled size for raid1.

Reported-by: Martin Steigerwald <Martin@lichtvoll.de>
Fixes: ba7b6e62f420 ("btrfs: adjust statfs calculations according to raid profiles")
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/btrfs/super.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1731,7 +1731,7 @@ static int btrfs_statfs(struct dentry *d
 	buf->f_bfree -= block_rsv->size >> bits;
 	spin_unlock(&block_rsv->lock);
 
-	buf->f_bavail = total_free_data;
+	buf->f_bavail = div_u64(total_free_data, factor);
 	ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
 	if (ret) {
 		mutex_unlock(&fs_info->chunk_mutex);