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| author | Mikulas Patocka <mpatocka@redhat.com> | 2010-08-12 04:14:26 +0100 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2010-08-12 04:14:26 +0100 |
| commit | 7b76ec11fec40203836b488496d2df082d5b2022 (patch) | |
| tree | 8b3c75295945f0533206c699139e55a30bcd426e /drivers/md | |
| parent | a79245b3e5669dc203fec63644d988c451fe55d5 (diff) | |
| download | linux-7b76ec11fec40203836b488496d2df082d5b2022.tar.gz linux-7b76ec11fec40203836b488496d2df082d5b2022.tar.bz2 linux-7b76ec11fec40203836b488496d2df082d5b2022.zip | |
dm stripe: support discards
The DM core will submit a discard bio to the stripe target for each
stripe in a striped DM device. The stripe target will determine
stripe-specific portions of the supplied bio to be remapped into
individual (at most 'num_discard_requests' extents). If a given
stripe-specific discard bio doesn't touch a particular stripe the bio
will be dropped.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/dm-stripe.c | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c index 1559fdfd2073..c297f6da91ea 100644 --- a/drivers/md/dm-stripe.c +++ b/drivers/md/dm-stripe.c @@ -176,6 +176,7 @@ static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv) ti->split_io = chunk_size; ti->num_flush_requests = stripes; + ti->num_discard_requests = stripes; sc->chunk_shift = ffs(chunk_size) - 1; sc->chunk_mask = ((sector_t) chunk_size) - 1; @@ -230,6 +231,39 @@ static void stripe_map_sector(struct stripe_c *sc, sector_t sector, *result = (chunk << sc->chunk_shift) | (offset & sc->chunk_mask); } +static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector, + uint32_t target_stripe, sector_t *result) +{ + uint32_t stripe; + + stripe_map_sector(sc, sector, &stripe, result); + if (stripe == target_stripe) + return; + *result &= ~sc->chunk_mask; /* round down */ + if (target_stripe < stripe) + *result += sc->chunk_mask + 1; /* next chunk */ +} + +static int stripe_map_discard(struct stripe_c *sc, struct bio *bio, + uint32_t target_stripe) +{ + sector_t begin, end; + + stripe_map_range_sector(sc, bio->bi_sector, target_stripe, &begin); + stripe_map_range_sector(sc, bio->bi_sector + bio_sectors(bio), + target_stripe, &end); + if (begin < end) { + bio->bi_bdev = sc->stripe[target_stripe].dev->bdev; + bio->bi_sector = begin + sc->stripe[target_stripe].physical_start; + bio->bi_size = to_bytes(end - begin); + return DM_MAPIO_REMAPPED; + } else { + /* The range doesn't map to the target stripe */ + bio_endio(bio, 0); + return DM_MAPIO_SUBMITTED; + } +} + static int stripe_map(struct dm_target *ti, struct bio *bio, union map_info *map_context) { @@ -243,6 +277,11 @@ static int stripe_map(struct dm_target *ti, struct bio *bio, bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev; return DM_MAPIO_REMAPPED; } + if (unlikely(bio->bi_rw & REQ_DISCARD)) { + target_request_nr = map_context->target_request_nr; + BUG_ON(target_request_nr >= sc->stripes); + return stripe_map_discard(sc, bio, target_request_nr); + } stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector); |