Re: [dm-devel] [PATCH 23/41] dm: implement REQ_FLUSH/FUA support for bio-based dm
From: Milan Broz <hidden>
Date: 2010-09-06 11:14:32
Also in:
dm-devel, linux-fsdevel, linux-raid, linux-scsi, lkml
On 09/03/2010 12:29 PM, Tejun Heo wrote:
quoted hunk ↗ jump to hunk
+++ b/drivers/md/dm-crypt.c@@ -1278,7 +1278,7 @@ static int crypt_map(struct dm_target *ti, struct bio *bio, struct dm_crypt_io *io; struct crypt_config *cc; - if (unlikely(bio_empty_barrier(bio))) { + if (bio->bi_rw & REQ_FLUSH) { cc = ti->private; bio->bi_bdev = cc->dev->bdev; return DM_MAPIO_REMAPPED;
...
quoted hunk ↗ jump to hunk
+++ b/drivers/md/dm.c@@ -1400,14 +1391,22 @@ static void __split_and_process_bio(struct mapped_device *md, struct bio *bio) ci.io->md = md; spin_lock_init(&ci.io->endio_lock); ci.sector = bio->bi_sector; - ci.sector_count = bio_sectors(bio); - if (unlikely(bio_empty_barrier(bio))) + if (!(bio->bi_rw & REQ_FLUSH)) + ci.sector_count = bio_sectors(bio); + else { + /* all FLUSH bio's reaching here should be empty */ + WARN_ON_ONCE(bio_has_data(bio)); ci.sector_count = 1; + }
I would add BUG_ON(bio_has_data(bio)) either to dm-crypt target or directly to DM core in this path. Note that empty barrier request bypass encryption layer now in dm-crypt, so if some bio with data payload reach it after the change, it causes data corruption (moreover plain data reach the disk directly). Milan