Commit c2ae7b77 authored by Naohiro Aota's avatar Naohiro Aota Committed by David Sterba
Browse files

btrfs: zoned: revive max_zone_append_bytes 



This patch is basically a revert of commit 5a80d1c6 ("btrfs: zoned:
remove max_zone_append_size logic"), but without unnecessary ASSERT and
check. The max_zone_append_size will be used as a hint to estimate the
number of extents to cover delalloc/writeback region in the later commits.

The size of a ZONE APPEND bio is also limited by queue_max_segments(), so
this commit considers it to calculate max_zone_append_size. Technically, a
bio can be larger than queue_max_segments() * PAGE_SIZE if the pages are
contiguous. But, it is safe to consider "queue_max_segments() * PAGE_SIZE"
as an upper limit of an extent size to calculate the number of extents
needed to write data.

Reviewed-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 65ea1b66

fs/btrfs/ctree.h

+2 −0
Original line number Diff line number Diff line
@@ -1070,6 +1070,8 @@ struct btrfs_fs_info { 
	 */

	u64 zone_size;



	/* Max size to emit ZONE_APPEND write command */

	u64 max_zone_append_size;

	struct mutex zoned_meta_io_lock;

	spinlock_t treelog_bg_lock;

	u64 treelog_bg;

fs/btrfs/zoned.c

+17 −0
Original line number Diff line number Diff line
@@ -415,6 +415,16 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device, bool populate_cache) 
	nr_sectors = bdev_nr_sectors(bdev);

	zone_info->zone_size_shift = ilog2(zone_info->zone_size);

	zone_info->nr_zones = nr_sectors >> ilog2(zone_sectors);

	/*

	 * We limit max_zone_append_size also by max_segments *

	 * PAGE_SIZE. Technically, we can have multiple pages per segment. But,

	 * since btrfs adds the pages one by one to a bio, and btrfs cannot

	 * increase the metadata reservation even if it increases the number of

	 * extents, it is safe to stick with the limit.

	 */

	zone_info->max_zone_append_size =

		min_t(u64, (u64)bdev_max_zone_append_sectors(bdev) << SECTOR_SHIFT,

		      (u64)bdev_max_segments(bdev) << PAGE_SHIFT);

	if (!IS_ALIGNED(nr_sectors, zone_sectors))

		zone_info->nr_zones++;
@@ -640,6 +650,7 @@ int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info) 
	u64 zoned_devices = 0;

	u64 nr_devices = 0;

	u64 zone_size = 0;

	u64 max_zone_append_size = 0;

	const bool incompat_zoned = btrfs_fs_incompat(fs_info, ZONED);

	int ret = 0;
@@ -674,6 +685,11 @@ int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info) 
				ret = -EINVAL;

				goto out;

			}

			if (!max_zone_append_size ||

			    (zone_info->max_zone_append_size &&

			     zone_info->max_zone_append_size < max_zone_append_size))

				max_zone_append_size =

					zone_info->max_zone_append_size;

		}

		nr_devices++;

	}
@@ -723,6 +739,7 @@ int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info) 
	}



	fs_info->zone_size = zone_size;

	fs_info->max_zone_append_size = max_zone_append_size;

	fs_info->fs_devices->chunk_alloc_policy = BTRFS_CHUNK_ALLOC_ZONED;



	/*

fs/btrfs/zoned.h

+1 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ struct btrfs_zoned_device_info { 
	 */

	u64 zone_size;

	u8  zone_size_shift;

	u64 max_zone_append_size;

	u32 nr_zones;

	unsigned int max_active_zones;

	atomic_t active_zones_left;