Btrfs: don't do async reclaim during log replay

Trying to reproduce a log enospc bug I hit a panic in the async reclaim code during log replay. This is because we use fs_info->fs_root as our root for shrinking and such. Technically we can use whatever root we want, but let's just not allow async reclaim while we're doing log replay. Thanks, Signed-off-by: Josef Bacik <[email protected]> Signed-off-by: Chris Mason <[email protected]>
torvalds · Sep 23, 2014 · f6acfd5 · f6acfd5
1 parent 47ab2a6
commit f6acfd5
Showing 1 changed file with 7 additions and 1 deletion.
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
@@ -4513,7 +4513,13 @@ static int reserve_metadata_bytes(struct btrfs_root *root,
 		space_info->flush = 1;
 	} else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
 		used += orig_bytes;
-		if (need_do_async_reclaim(space_info, root->fs_info, used) &&
+		/*
+		 * We will do the space reservation dance during log replay,
+		 * which means we won't have fs_info->fs_root set, so don't do
+		 * the async reclaim as we will panic.
+		 */
+		if (!root->fs_info->log_root_recovering &&
+		    need_do_async_reclaim(space_info, root->fs_info, used) &&
 		    !work_busy(&root->fs_info->async_reclaim_work))
 			queue_work(system_unbound_wq,
 				   &root->fs_info->async_reclaim_work);