Commit 01e86008 authored by Johannes Thumshirn's avatar Johannes Thumshirn Committed by David Sterba
Browse files

btrfs: zoned: reset zones of relocated block groups 

When relocating a block group the freed up space is not discarded in one
big block, but each extent is discarded on its own with -odisard=sync.

For a zoned filesystem we need to discard the whole block group at once,
so btrfs_discard_extent() will translate the discard into a
REQ_OP_ZONE_RESET operation, which then resets the device's zone.
Failure to reset the zone is not fatal error.

Discussion about the approach and regarding transaction blocking:
https://lore.kernel.org/linux-btrfs/CAL3q7H4SjS_d5rBepfTMhU8Th3bJzdmyYd0g4Z60yUgC_rC_ZA@mail.gmail.com/



Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Reviewed-by: default avatarFilipe Manana <fdmanana@suse.com>
Signed-off-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent e9306ad4

fs/btrfs/volumes.c

+16 −0
Original line number Diff line number Diff line
@@ -3103,6 +3103,7 @@ static int btrfs_relocate_chunk(struct btrfs_fs_info *fs_info, u64 chunk_offset) 
	struct btrfs_root *root = fs_info->chunk_root;

	struct btrfs_trans_handle *trans;

	struct btrfs_block_group *block_group;

	u64 length;

	int ret;



	/*
@@ -3130,8 +3131,23 @@ static int btrfs_relocate_chunk(struct btrfs_fs_info *fs_info, u64 chunk_offset) 
	if (!block_group)

		return -ENOENT;

	btrfs_discard_cancel_work(&fs_info->discard_ctl, block_group);

	length = block_group->length;

	btrfs_put_block_group(block_group);



	/*

	 * On a zoned file system, discard the whole block group, this will

	 * trigger a REQ_OP_ZONE_RESET operation on the device zone. If

	 * resetting the zone fails, don't treat it as a fatal problem from the

	 * filesystem's point of view.

	 */

	if (btrfs_is_zoned(fs_info)) {

		ret = btrfs_discard_extent(fs_info, chunk_offset, length, NULL);

		if (ret)

			btrfs_info(fs_info,

				"failed to reset zone %llu after relocation",

				chunk_offset);

	}



	trans = btrfs_start_trans_remove_block_group(root->fs_info,

						     chunk_offset);

	if (IS_ERR(trans)) {