From: Josef Bacik <josef@redhat.com>
Date: Thu, 22 Sep 2011 18:30:02 +0000 (-0400)
Subject: Btrfs: check unused against how much space we actually want
X-Git-Tag: firefly_0821_release~3680^2~3894^2~78^2~23
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=ef3be45722317f8c2fb0e861065df0c3830ff9ac;p=firefly-linux-kernel-4.4.55.git

Btrfs: check unused against how much space we actually want

There is a bug that may lead to early ENOSPC in our reservation code.  We've
been checking against num_bytes which may be above and beyond what we want to
actually reserve, which could give us a false ENOSPC.  Fix this by making sure
the unused space is above how much we want to reserve and not how much we're
trying to flush.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
---

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 5498bdacd4c3..fd65f6bc676c 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3472,7 +3472,7 @@ again:
 	 */
 	if (unused <= space_info->total_bytes) {
 		unused = space_info->total_bytes - unused;
-		if (unused >= num_bytes) {
+		if (unused >= orig_bytes) {
 			space_info->bytes_may_use += orig_bytes;
 			ret = 0;
 		} else {