Btrfs: free csums when we're done scrubbing an extent

A user reported scrub taking up an unreasonable amount of ram as it ran.  This
is because we lookup the csums for the extent we're scrubbing but don't free it
up until after we're done with the scrub, which means we can take up a whole lot
of ram.  This patch fixes this by dropping the csums once we're done with the
extent we've scrubbed.  The user reported this to fix their problem.  Thanks,

Reported-and-tested-by: Remco Hosman <remco@hosman.xs4all.nl>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 79bd479317cb53cbea30a7021d81a891ed9ae20c..cb308a3a93006d7810ae31ee8197887fca42ba9e 100644 (file)
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -2505,6 +2505,7 @@ again:
                        if (ret)
                                goto out;
 
+                       scrub_free_csums(sctx);
                        if (extent_logical + extent_len <
                            key.objectid + bytes) {
                                logical += increment;