Commit 5a488b9d authored by Liu Bo's avatar Liu Bo Committed by David Sterba
Browse files

Btrfs: fix unexpected balance crash due to BUG_ON 



Mounting a btrfs can resume previous balance operations asynchronously.
An user got a crash when one drive has some corrupt sectors.

Since balance can cancel itself in case of any error, we can gracefully
return errors to upper layers and let balance do the cancel job.

Reported-by: default avatarsash <master.b.at.raven@chefmail.de>
Signed-off-by: default avatarLiu Bo <bo.li.liu@oracle.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 0fd8c3da

fs/btrfs/volumes.c

+24 −4
Original line number Diff line number Diff line
@@ -3460,7 +3460,7 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info) 
	u64 size_to_free;

	u64 chunk_type;

	struct btrfs_chunk *chunk;

	struct btrfs_path *path;

	struct btrfs_path *path = NULL;

	struct btrfs_key key;

	struct btrfs_key found_key;

	struct btrfs_trans_handle *trans;
@@ -3494,13 +3494,33 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info) 
		ret = btrfs_shrink_device(device, old_size - size_to_free);

		if (ret == -ENOSPC)

			break;

		BUG_ON(ret);

		if (ret) {

			/* btrfs_shrink_device never returns ret > 0 */

			WARN_ON(ret > 0);

			goto error;

		}



		trans = btrfs_start_transaction(dev_root, 0);

		BUG_ON(IS_ERR(trans));

		if (IS_ERR(trans)) {

			ret = PTR_ERR(trans);

			btrfs_info_in_rcu(fs_info,

		 "resize: unable to start transaction after shrinking device %s (error %d), old size %llu, new size %llu",

					  rcu_str_deref(device->name), ret,

					  old_size, old_size - size_to_free);

			goto error;

		}



		ret = btrfs_grow_device(trans, device, old_size);

		BUG_ON(ret);

		if (ret) {

			btrfs_end_transaction(trans, dev_root);

			/* btrfs_grow_device never returns ret > 0 */

			WARN_ON(ret > 0);

			btrfs_info_in_rcu(fs_info,

		 "resize: unable to grow device after shrinking device %s (error %d), old size %llu, new size %llu",

					  rcu_str_deref(device->name), ret,

					  old_size, old_size - size_to_free);

			goto error;

		}



		btrfs_end_transaction(trans, dev_root);

	}

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