DM targets must not split zone append and write operations using
dm_accept_partial_bio() as doing so is forbidden for zone append BIOs,
breaks zone append emulation using regular write BIOs and potentially
creates deadlock situations with queue freeze operations.
Modify dm_accept_partial_bio() to add missing BUG_ON() checks for all
these cases, that is, check that the BIO is a write or write zeroes
operation. This change packs all the zone related checks together under
a static_branch_unlikely(&zoned_enabled) and done only if the target is
a zoned device.
Fixes: f211268ed1f9 ("dm: Use the block layer zone append emulation")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
---
drivers/md/dm.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index f1e63c1808b4..f82457e7eed1 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1286,8 +1286,9 @@ static size_t dm_dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
/*
* A target may call dm_accept_partial_bio only from the map routine. It is
* allowed for all bio types except REQ_PREFLUSH, REQ_OP_ZONE_* zone management
- * operations, REQ_OP_ZONE_APPEND (zone append writes) and any bio serviced by
- * __send_duplicate_bios().
+ * operations, zone append writes (native with REQ_OP_ZONE_APPEND or emulated
+ * with write BIOs flagged with BIO_EMULATES_ZONE_APPEND) and any bio serviced
+ * by __send_duplicate_bios().
*
* dm_accept_partial_bio informs the dm that the target only wants to process
* additional n_sectors sectors of the bio and the rest of the data should be
@@ -1320,11 +1321,19 @@ void dm_accept_partial_bio(struct bio *bio, unsigned int n_sectors)
unsigned int bio_sectors = bio_sectors(bio);
BUG_ON(dm_tio_flagged(tio, DM_TIO_IS_DUPLICATE_BIO));
- BUG_ON(op_is_zone_mgmt(bio_op(bio)));
- BUG_ON(bio_op(bio) == REQ_OP_ZONE_APPEND);
BUG_ON(bio_sectors > *tio->len_ptr);
BUG_ON(n_sectors > bio_sectors);
+ if (static_branch_unlikely(&zoned_enabled) &&
+ unlikely(bdev_is_zoned(bio->bi_bdev))) {
+ enum req_op op = bio_op(bio);
+
+ BUG_ON(op_is_zone_mgmt(op));
+ BUG_ON(op == REQ_OP_WRITE);
+ BUG_ON(op == REQ_OP_WRITE_ZEROES);
+ BUG_ON(op == REQ_OP_ZONE_APPEND);
+ }
+
*tio->len_ptr -= bio_sectors - n_sectors;
bio->bi_iter.bi_size = n_sectors << SECTOR_SHIFT;
--
2.49.0
