Commit 2dd7e7bc authored by Naohiro Aota's avatar Naohiro Aota Committed by David Sterba
Browse files

btrfs: zoned: wait for extent buffer IOs before finishing a zone 



Before sending REQ_OP_ZONE_FINISH to a zone, we need to ensure that
ongoing IOs already finished. Or, we will see a "Zone Is Full" error for
the IOs, as the ZONE_FINISH command makes the zone full.

We ensure that with btrfs_wait_block_group_reservations() and
btrfs_wait_ordered_roots() for a data block group. And, for a metadata
block group, the comparison of alloc_offset vs meta_write_pointer mostly
ensures IOs for the allocated region already sent. However, there still
can be a little time frame where the IOs are sent but not yet completed.

Introduce wait_eb_writebacks() to ensure such IOs are completed for a
metadata block group. It walks the buffer_radix to find extent buffers in
the block group and calls wait_on_extent_buffer_writeback() on them.

Fixes: afba2bc0 ("btrfs: zoned: implement active zone tracking")
CC: stable@vger.kernel.org # 5.19+
Signed-off-by: default avatarNaohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent a362bb86

fs/btrfs/zoned.c

+38 −2
Original line number Diff line number Diff line
@@ -1918,10 +1918,44 @@ bool btrfs_zone_activate(struct btrfs_block_group *block_group) 
	return ret;

}



static void wait_eb_writebacks(struct btrfs_block_group *block_group)

{

	struct btrfs_fs_info *fs_info = block_group->fs_info;

	const u64 end = block_group->start + block_group->length;

	struct radix_tree_iter iter;

	struct extent_buffer *eb;

	void __rcu **slot;



	rcu_read_lock();

	radix_tree_for_each_slot(slot, &fs_info->buffer_radix, &iter,

				 block_group->start >> fs_info->sectorsize_bits) {

		eb = radix_tree_deref_slot(slot);

		if (!eb)

			continue;

		if (radix_tree_deref_retry(eb)) {

			slot = radix_tree_iter_retry(&iter);

			continue;

		}



		if (eb->start < block_group->start)

			continue;

		if (eb->start >= end)

			break;



		slot = radix_tree_iter_resume(slot, &iter);

		rcu_read_unlock();

		wait_on_extent_buffer_writeback(eb);

		rcu_read_lock();

	}

	rcu_read_unlock();

}



static int do_zone_finish(struct btrfs_block_group *block_group, bool fully_written)

{

	struct btrfs_fs_info *fs_info = block_group->fs_info;

	struct map_lookup *map;

	const bool is_metadata = (block_group->flags &

			(BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_SYSTEM));

	int ret = 0;

	int i;
@@ -1932,8 +1966,7 @@ static int do_zone_finish(struct btrfs_block_group *block_group, bool fully_writ 
	}



	/* Check if we have unwritten allocated space */

	if ((block_group->flags &

	     (BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_SYSTEM)) &&

	if (is_metadata &&

	    block_group->start + block_group->alloc_offset > block_group->meta_write_pointer) {

		spin_unlock(&block_group->lock);

		return -EAGAIN;
@@ -1958,6 +1991,9 @@ static int do_zone_finish(struct btrfs_block_group *block_group, bool fully_writ 
		/* No need to wait for NOCOW writers. Zoned mode does not allow that */

		btrfs_wait_ordered_roots(fs_info, U64_MAX, block_group->start,

					 block_group->length);

		/* Wait for extent buffers to be written. */

		if (is_metadata)

			wait_eb_writebacks(block_group);



		spin_lock(&block_group->lock);