[PATCH v4 6/8] zonefs: use zone write granularity as block size

Damien Le Moal
2021-01-28T04:51:11Z

Zoned block devices have different granularity constraints for write
operations into sequential zones. E.g. ZBC and ZAC devices require that
writes be aligned to the device physical block size while NVMe ZNS
devices allow logical block size aligned write operations. To correctly
handle such difference, use the device zone write granularity limit to
set the block size of a zonefs volume, thus allowing the smallest
possible write unit for all zoned device types.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
---
fs/zonefs/super.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
index ab68e27bb322..b9fb55b250ae 100644
--- a/fs/zonefs/super.c
+++ b/fs/zonefs/super.c
@@ -1581,12 +1581,11 @@ static int zonefs_fill_super(struct super_block *sb, void *data, int silent)
sb->s_time_gran = 1;

/*
- * The block size is set to the device physical sector size to ensure
- * that write operations on 512e devices (512B logical block and 4KB
- * physical block) are always aligned to the device physical blocks,
- * as mandated by the ZBC/ZAC specifications.
+ * The block size is set to the device zone write granularity to ensure
+ * that write operations are always aligned according to the device
+ * interface constraints.
*/
- sb_set_blocksize(sb, bdev_physical_block_size(sb->s_bdev));
+ sb_set_blocksize(sb, bdev_zone_write_granularity(sb->s_bdev));
sbi->s_zone_sectors_shift = ilog2(bdev_zone_sectors(sb->s_bdev));
sbi->s_uid = GLOBAL_ROOT_UID;
sbi->s_gid = GLOBAL_ROOT_GID;
--
2.29.2