1 files changed, 33 insertions, 14 deletions

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index d721c66d0b41..37418b183b07 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -123,7 +123,16 @@ void btrfs_put_block_group(struct btrfs_block_group *cache)
 {
 	if (refcount_dec_and_test(&cache->refs)) {
 		WARN_ON(cache->pinned > 0);
-		WARN_ON(cache->reserved > 0);
+		/*
+		 * If there was a failure to cleanup a log tree, very likely due
+		 * to an IO failure on a writeback attempt of one or more of its
+		 * extent buffers, we could not do proper (and cheap) unaccounting
+		 * of their reserved space, so don't warn on reserved > 0 in that
+		 * case.
+		 */
+		if (!(cache->flags & BTRFS_BLOCK_GROUP_METADATA) ||
+		    !BTRFS_FS_LOG_CLEANUP_ERROR(cache->fs_info))
+			WARN_ON(cache->reserved > 0);
 
 		/*
 		 * A block_group shouldn't be on the discard_list anymore.
@@ -1491,13 +1500,16 @@ void btrfs_reclaim_bgs_work(struct work_struct *work)
 		container_of(work, struct btrfs_fs_info, reclaim_bgs_work);
 	struct btrfs_block_group *bg;
 	struct btrfs_space_info *space_info;
-	LIST_HEAD(again_list);
 
 	if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
 		return;
 
-	if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE))
+	sb_start_write(fs_info->sb);
+
+	if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE)) {
+		sb_end_write(fs_info->sb);
 		return;
+	}
 
 	/*
 	 * Long running balances can keep us blocked here for eternity, so
@@ -1505,6 +1517,7 @@ void btrfs_reclaim_bgs_work(struct work_struct *work)
 	 */
 	if (!mutex_trylock(&fs_info->reclaim_bgs_lock)) {
 		btrfs_exclop_finish(fs_info);
+		sb_end_write(fs_info->sb);
 		return;
 	}
 
@@ -1562,21 +1575,18 @@ void btrfs_reclaim_bgs_work(struct work_struct *work)
 				div64_u64(zone_unusable * 100, bg->length));
 		trace_btrfs_reclaim_block_group(bg);
 		ret = btrfs_relocate_chunk(fs_info, bg->start);
-		if (ret && ret != -EAGAIN)
+		if (ret)
 			btrfs_err(fs_info, "error relocating chunk %llu",
 				  bg->start);
 
 next:
+		btrfs_put_block_group(bg);
 		spin_lock(&fs_info->unused_bgs_lock);
-		if (ret == -EAGAIN && list_empty(&bg->bg_list))
-			list_add_tail(&bg->bg_list, &again_list);
-		else
-			btrfs_put_block_group(bg);
 	}
-	list_splice_tail(&again_list, &fs_info->reclaim_bgs);
 	spin_unlock(&fs_info->unused_bgs_lock);
 	mutex_unlock(&fs_info->reclaim_bgs_lock);
 	btrfs_exclop_finish(fs_info);
+	sb_end_write(fs_info->sb);
 }
 
 void btrfs_reclaim_bgs(struct btrfs_fs_info *fs_info)
@@ -2872,7 +2882,6 @@ int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans)
 	struct btrfs_path *path = NULL;
 	LIST_HEAD(dirty);
 	struct list_head *io = &cur_trans->io_bgs;
-	int num_started = 0;
 	int loops = 0;
 
 	spin_lock(&cur_trans->dirty_bgs_lock);
@@ -2938,7 +2947,6 @@ again:
 			cache->io_ctl.inode = NULL;
 			ret = btrfs_write_out_cache(trans, cache, path);
 			if (ret == 0 && cache->io_ctl.inode) {
-				num_started++;
 				should_put = 0;
 
 				/*
@@ -3039,7 +3047,6 @@ int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans)
 	int should_put;
 	struct btrfs_path *path;
 	struct list_head *io = &cur_trans->io_bgs;
-	int num_started = 0;
 
 	path = btrfs_alloc_path();
 	if (!path)
@@ -3097,7 +3104,6 @@ int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans)
 			cache->io_ctl.inode = NULL;
 			ret = btrfs_write_out_cache(trans, cache, path);
 			if (ret == 0 && cache->io_ctl.inode) {
-				num_started++;
 				should_put = 0;
 				list_add_tail(&cache->io_list, io);
 			} else {
@@ -3893,9 +3899,22 @@ int btrfs_free_block_groups(struct btrfs_fs_info *info)
 		 * important and indicates a real bug if this happens.
 		 */
 		if (WARN_ON(space_info->bytes_pinned > 0 ||
-			    space_info->bytes_reserved > 0 ||
 			    space_info->bytes_may_use > 0))
 			btrfs_dump_space_info(info, space_info, 0, 0);
+
+		/*
+		 * If there was a failure to cleanup a log tree, very likely due
+		 * to an IO failure on a writeback attempt of one or more of its
+		 * extent buffers, we could not do proper (and cheap) unaccounting
+		 * of their reserved space, so don't warn on bytes_reserved > 0 in
+		 * that case.
+		 */
+		if (!(space_info->flags & BTRFS_BLOCK_GROUP_METADATA) ||
+		    !BTRFS_FS_LOG_CLEANUP_ERROR(info)) {
+			if (WARN_ON(space_info->bytes_reserved > 0))
+				btrfs_dump_space_info(info, space_info, 0, 0);
+		}
+
 		WARN_ON(space_info->reclaim_size > 0);
 		list_del(&space_info->list);
 		btrfs_sysfs_remove_space_info(space_info);