Commit 1ada69f6 authored by Naohiro Aota's avatar Naohiro Aota Committed by David Sterba
Browse files

btrfs: zoned: unset dedicated block group on allocation failure 



Allocating an extent from a block group can fail for various reasons.
When an allocation from a dedicated block group (for tree-log or
relocation data) fails, we need to unregister it as a dedicated one so
that we can allocate a new block group for the dedicated one.

However, we are returning early when the block group in case it is
read-only, fully used, or not be able to activate the zone. As a result,
we keep the non-usable block group as a dedicated one, leading to
further allocation failure. With many block groups, the allocator will
iterate hopeless loop to find a free extent, results in a hung task.

Fix the issue by delaying the return and doing the proper cleanups.

CC: stable@vger.kernel.org # 5.16
Signed-off-by: default avatarNaohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 73672710

fs/btrfs/extent-tree.c

+16 −4
Original line number Diff line number Diff line
@@ -3805,23 +3805,35 @@ static int do_allocation_zoned(struct btrfs_block_group *block_group, 
	spin_unlock(&fs_info->relocation_bg_lock);

	if (skip)

		return 1;



	/* Check RO and no space case before trying to activate it */

	spin_lock(&block_group->lock);

	if (block_group->ro ||

	    block_group->alloc_offset == block_group->zone_capacity) {

		spin_unlock(&block_group->lock);

		return 1;

		ret = 1;

		/*

		 * May need to clear fs_info->{treelog,data_reloc}_bg.

		 * Return the error after taking the locks.

		 */

	}

	spin_unlock(&block_group->lock);



	if (!btrfs_zone_activate(block_group))

		return 1;

	if (!ret && !btrfs_zone_activate(block_group)) {

		ret = 1;

		/*

		 * May need to clear fs_info->{treelog,data_reloc}_bg.

		 * Return the error after taking the locks.

		 */

	}



	spin_lock(&space_info->lock);

	spin_lock(&block_group->lock);

	spin_lock(&fs_info->treelog_bg_lock);

	spin_lock(&fs_info->relocation_bg_lock);



	if (ret)

		goto out;



	ASSERT(!ffe_ctl->for_treelog ||

	       block_group->start == fs_info->treelog_bg ||

	       fs_info->treelog_bg == 0);