From: Chris Mason <chris.mason@oracle.com>
Date: Fri, 24 Dec 2010 11:41:52 +0000 (-0500)
Subject: Btrfs: fix off by one while setting block groups readonly
X-Git-Tag: Ubuntu-5.0.0-8.9~20289^2~17
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=65e5341b9a0c39767ae1fecc727d70eda0dd6d83;p=mirror_ubuntu-disco-kernel.git

Btrfs: fix off by one while setting block groups readonly

When we read in block groups, we'll set non-redundant groups
readonly if we find a raid1, DUP or raid10 group.  But the
ro code has an off by one bug in the math around testing to
make sure out accounting doesn't go wrong.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
---

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 7e5162e5c411..b180efdc8b68 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -7971,13 +7971,14 @@ static int set_block_group_ro(struct btrfs_block_group_cache *cache)
 
 	if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
 	    sinfo->bytes_may_use + sinfo->bytes_readonly +
-	    cache->reserved_pinned + num_bytes < sinfo->total_bytes) {
+	    cache->reserved_pinned + num_bytes <= sinfo->total_bytes) {
 		sinfo->bytes_readonly += num_bytes;
 		sinfo->bytes_reserved += cache->reserved_pinned;
 		cache->reserved_pinned = 0;
 		cache->ro = 1;
 		ret = 0;
 	}
+
 	spin_unlock(&cache->lock);
 	spin_unlock(&sinfo->lock);
 	return ret;