diff mbox

Btrfs: fix the allocator loop logic

Message ID 1306527315-3927-1-git-send-email-josef@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Josef Bacik May 27, 2011, 8:15 p.m. UTC
I was testing with empty_cluster = 0 to try and reproduce a problem and kept
hitting early enospc panics.  This was because our loop logic was a little
confused.  So this is what I did

1) Make the loop variable the ultimate decider on wether we should loop again
isntead of checking to see if we had an uncached bg, empty size or empty
cluster.

2) Increment loop before checking to see what we are on to make the loop
definitions make more sense.

3) If we are on the chunk alloc loop don't set empty_size/empty_cluster to 0
unless we didn't actually allocate a chunk.  If we did allocate a chunk we
should be able to easily setup a new cluster so clearing
empty_size/empty_cluster makes us less efficient.

This kept me from hitting panics while trying to reproduce the other problem.
Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
---
 fs/btrfs/extent-tree.c |   48 +++++++++++++++++++++++++-----------------------
 1 files changed, 25 insertions(+), 23 deletions(-)
diff mbox

Patch

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index b4f67e8..cb4bbc9 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -5360,9 +5360,7 @@  loop:
 	 * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
 	 *			again
 	 */
-	if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE &&
-	    (found_uncached_bg || empty_size || empty_cluster ||
-	     allowed_chunk_alloc)) {
+	if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
 		index = 0;
 		if (loop == LOOP_FIND_IDEAL && found_uncached_bg) {
 			found_uncached_bg = false;
@@ -5402,32 +5400,36 @@  loop:
 			goto search;
 		}
 
-		if (loop < LOOP_CACHING_WAIT) {
-			loop++;
-			goto search;
-		}
+		loop++;
 
 		if (loop == LOOP_ALLOC_CHUNK) {
-			empty_size = 0;
-			empty_cluster = 0;
-		}
+		       if (allowed_chunk_alloc) {
+				ret = do_chunk_alloc(trans, root, num_bytes +
+						     2 * 1024 * 1024, data,
+						     CHUNK_ALLOC_LIMITED);
+				allowed_chunk_alloc = 0;
+				if (ret == 1)
+					done_chunk_alloc = 1;
+			} else if (!done_chunk_alloc &&
+				   space_info->force_alloc ==
+				   CHUNK_ALLOC_NO_FORCE) {
+				space_info->force_alloc = CHUNK_ALLOC_LIMITED;
+			}
 
-		if (allowed_chunk_alloc) {
-			ret = do_chunk_alloc(trans, root, num_bytes +
-					     2 * 1024 * 1024, data,
-					     CHUNK_ALLOC_LIMITED);
-			allowed_chunk_alloc = 0;
-			done_chunk_alloc = 1;
-		} else if (!done_chunk_alloc &&
-			   space_info->force_alloc == CHUNK_ALLOC_NO_FORCE) {
-			space_info->force_alloc = CHUNK_ALLOC_LIMITED;
+		       /*
+			* We didn't allocate a chunk, go ahead and drop the
+			* empty size and loop again.
+			*/
+		       if (!done_chunk_alloc)
+			       loop = LOOP_NO_EMPTY_SIZE;
 		}
 
-		if (loop < LOOP_NO_EMPTY_SIZE) {
-			loop++;
-			goto search;
+		if (loop == LOOP_NO_EMPTY_SIZE) {
+			empty_size = 0;
+			empty_cluster = 0;
 		}
-		ret = -ENOSPC;
+
+		goto search;
 	} else if (!ins->objectid) {
 		ret = -ENOSPC;
 	} else if (ins->objectid) {