diff options
| author | Joe Thornber <ejt@redhat.com> | 2014-10-10 09:41:09 +0100 |
|---|---|---|
| committer | Mister Oyster <oysterized@gmail.com> | 2018-01-02 14:19:42 +0100 |
| commit | 159a1e9907c6d14475c6c3d46e91e616e567c993 (patch) | |
| tree | c3b499fd83bc40f37c5241b792bbfc2ce57de6ef /drivers | |
| parent | 711e09b94d1a4f56482166b53a9bf0e33916a5f0 (diff) | |
dm thin: grab a virtual cell before looking up the mapping
Avoids normal IO racing with discard.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Joe Maples <joe@frap129.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/md/dm-thin.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index 154333224..1363d76ed 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -1496,6 +1496,14 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio) return DM_MAPIO_SUBMITTED; } + /* + * We must hold the virtual cell before doing the lookup, otherwise + * there's a race with discard. + */ + build_virtual_key(tc->td, block, &key); + if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1, &cell_result)) + return DM_MAPIO_SUBMITTED; + r = dm_thin_find_block(td, block, 0, &result); /* @@ -1519,13 +1527,10 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio) * shared flag will be set in their case. */ thin_defer_bio(tc, bio); + cell_defer_no_holder_no_free(tc, &cell1); return DM_MAPIO_SUBMITTED; } - build_virtual_key(tc->td, block, &key); - if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1, &cell_result)) - return DM_MAPIO_SUBMITTED; - build_data_key(tc->td, result.block, &key); if (dm_bio_detain(tc->pool->prison, &key, bio, &cell2, &cell_result)) { cell_defer_no_holder_no_free(tc, &cell1); @@ -1546,6 +1551,7 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio) * of doing so. */ handle_unserviceable_bio(tc->pool, bio); + cell_defer_no_holder_no_free(tc, &cell1); return DM_MAPIO_SUBMITTED; } /* fall through */ @@ -1556,6 +1562,7 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio) * provide the hint to load the metadata into cache. */ thin_defer_bio(tc, bio); + cell_defer_no_holder_no_free(tc, &cell1); return DM_MAPIO_SUBMITTED; default: @@ -1565,6 +1572,7 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio) * pool is switched to fail-io mode. */ bio_io_error(bio); + cell_defer_no_holder_no_free(tc, &cell1); return DM_MAPIO_SUBMITTED; } } |