Commit 760e69c4 authored by Naohiro Aota's avatar Naohiro Aota Committed by David Sterba
Browse files

btrfs: zoned: activate block group only for extent allocation 



In btrfs_make_block_group(), we activate the allocated block group,
expecting that the block group is soon used for allocation. However, the
chunk allocation from flush_space() context broke the assumption. There
can be a large time gap between the chunk allocation time and the extent
allocation time from the chunk.

Activating the empty block groups pre-allocated from flush_space()
context can exhaust the active zone counter of a device. Once we use all
the active zone counts for empty pre-allocated block groups, we cannot
activate new block group for the other things: metadata, tree-log, or
data relocation block group.  That failure results in a fake -ENOSPC.

This patch introduces CHUNK_ALLOC_FORCE_FOR_EXTENT to distinguish the
chunk allocation from find_free_extent(). Now, the new block group is
activated only in that context.

Fixes: eb66a010 ("btrfs: zoned: activate new block group")
CC: stable@vger.kernel.org # 5.16+
Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Tested-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: default avatarNaohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 820c363b

fs/btrfs/block-group.c

+16 −8
Original line number Diff line number Diff line
@@ -2503,12 +2503,6 @@ struct btrfs_block_group *btrfs_make_block_group(struct btrfs_trans_handle *tran 
		return ERR_PTR(ret);

	}



	/*

	 * New block group is likely to be used soon. Try to activate it now.

	 * Failure is OK for now.

	 */

	btrfs_zone_activate(cache);



	ret = exclude_super_stripes(cache);

	if (ret) {

		/* We may have excluded something, so call this just in case */
@@ -3660,8 +3654,14 @@ int btrfs_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags, 
	struct btrfs_block_group *ret_bg;

	bool wait_for_alloc = false;

	bool should_alloc = false;

	bool from_extent_allocation = false;

	int ret = 0;



	if (force == CHUNK_ALLOC_FORCE_FOR_EXTENT) {

		from_extent_allocation = true;

		force = CHUNK_ALLOC_FORCE;

	}



	/* Don't re-enter if we're already allocating a chunk */

	if (trans->allocating_chunk)

		return -ENOSPC;
@@ -3754,9 +3754,17 @@ int btrfs_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags, 
	ret_bg = do_chunk_alloc(trans, flags);

	trans->allocating_chunk = false;



	if (IS_ERR(ret_bg))

	if (IS_ERR(ret_bg)) {

		ret = PTR_ERR(ret_bg);

	else

	} else if (from_extent_allocation) {

		/*

		 * New block group is likely to be used soon. Try to activate

		 * it now. Failure is OK for now.

		 */

		btrfs_zone_activate(ret_bg);

	}



	if (!ret)

		btrfs_put_block_group(ret_bg);



	spin_lock(&space_info->lock);

fs/btrfs/block-group.h

+4 −0
Original line number Diff line number Diff line
@@ -35,11 +35,15 @@ enum btrfs_discard_state { 
 * the FS with empty chunks

 *

 * CHUNK_ALLOC_FORCE means it must try to allocate one

 *

 * CHUNK_ALLOC_FORCE_FOR_EXTENT like CHUNK_ALLOC_FORCE but called from

 * find_free_extent() that also activaes the zone

 */

enum btrfs_chunk_alloc_enum {

	CHUNK_ALLOC_NO_FORCE,

	CHUNK_ALLOC_LIMITED,

	CHUNK_ALLOC_FORCE,

	CHUNK_ALLOC_FORCE_FOR_EXTENT,

};



struct btrfs_caching_control {

fs/btrfs/extent-tree.c

+1 −1
Original line number Diff line number Diff line
@@ -4082,7 +4082,7 @@ static int find_free_extent_update_loop(struct btrfs_fs_info *fs_info, 
			}



			ret = btrfs_chunk_alloc(trans, ffe_ctl->flags,

						CHUNK_ALLOC_FORCE);

						CHUNK_ALLOC_FORCE_FOR_EXTENT);



			/* Do not bail out on ENOSPC since we can do more. */

			if (ret == -ENOSPC)