On 10/30/20 9:51 AM, Naohiro Aota wrote:
This commit enables zone append writing for zoned btrfs. When using zone append, a bio is issued to the start of a target zone and the device decides to place it inside the zone. Upon completion the device reports the actual written position back to the host. Three parts are necessary to enable zone append in btrfs. First, modify the bio to use REQ_OP_ZONE_APPEND in btrfs_submit_bio_hook() and adjust the bi_sector to point the beginning of the zone. Secondly, records the returned physical address (and disk/partno) to the ordered extent in end_bio_extent_writepage() after the bio has been completed. We cannot resolve the physical address to the logical address because we can neither take locks nor allocate a buffer in this end_bio context. So, we need to record the physical address to resolve it later in btrfs_finish_ordered_io(). And finally, rewrites the logical addresses of the extent mapping and checksum data according to the physical address (using __btrfs_rmap_block). If the returned address matches the originally allocated address, we can skip this rewriting process. Signed-off-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx> Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx>
I hate this, but I suppose its better than forcing us to wait for ordered extents in order of submission, and I can't really think of anything better,
Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx> Thanks, Josef
