From: Ilya Dryomov <idryomov@gmail.com>
Date: Tue, 12 Feb 2013 16:28:59 +0000 (+0000)
Subject: Btrfs: allow for selecting only completely empty chunks
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=3e39cea61c4ecb5774c08f3e30507fdd58c1cca9;p=openwrt%2Fstaging%2Fblogic.git

Btrfs: allow for selecting only completely empty chunks

Enhance balance usage filter by making it possible to balance out only
completely empty chunks.  Today, usage filter properly acts on values
from 1 to 99 inclusive, usage=100 selects all chunks, and usage=0
selects no chunks.  This commit changes the usage=0 case: the new
meaning is to restripe only completely empty chunks and nothing else.

Suggested-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
---

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index d778e9666597..567076542d1d 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2679,7 +2679,7 @@ static int chunk_usage_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
 	chunk_used = btrfs_block_group_used(&cache->item);
 
 	if (bargs->usage == 0)
-		user_thresh = 0;
+		user_thresh = 1;
 	else if (bargs->usage > 100)
 		user_thresh = cache->key.offset;
 	else