From: Naohiro Aota naohiro.aota@wdc.com
commit c2ae7b772ef4e86c5ddf3fd47bf59045ae96a414 upstream
This patch is basically a revert of commit 5a80d1c6a270 ("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: Johannes Thumshirn johannes.thumshirn@wdc.com Signed-off-by: Naohiro Aota naohiro.aota@wdc.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/ctree.h | 2 ++ fs/btrfs/zoned.c | 17 +++++++++++++++++ fs/btrfs/zoned.h | 1 + 3 files changed, 20 insertions(+)
--- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1017,6 +1017,8 @@ struct btrfs_fs_info { u64 zoned; };
+ /* 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; --- a/fs/btrfs/zoned.c +++ b/fs/btrfs/zoned.c @@ -386,6 +386,16 @@ int btrfs_get_dev_zone_info(struct btrfs 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++;
@@ -570,6 +580,7 @@ int btrfs_check_zoned_mode(struct btrfs_ 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;
@@ -605,6 +616,11 @@ int btrfs_check_zoned_mode(struct btrfs_ 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++; } @@ -654,6 +670,7 @@ int btrfs_check_zoned_mode(struct btrfs_ }
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;
/* --- a/fs/btrfs/zoned.h +++ b/fs/btrfs/zoned.h @@ -23,6 +23,7 @@ struct btrfs_zoned_device_info { */ u64 zone_size; u8 zone_size_shift; + u64 max_zone_append_size; u32 nr_zones; unsigned long *seq_zones; unsigned long *empty_zones;