6.16-stable review patch. If anyone has any objections, please let me know.
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From: Damien Le Moal dlemoal@kernel.org
commit 409f9287dab3b53bffe8d28d883a529028aa6a42 upstream.
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@vger.kernel.org Signed-off-by: Damien Le Moal dlemoal@kernel.org Reviewed-by: Mikulas Patocka mpatocka@redhat.com Link: https://lore.kernel.org/r/20250625093327.548866-6-dlemoal@kernel.org Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/md/dm.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-)
--- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1293,8 +1293,9 @@ out: /* * 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 @@ -1327,11 +1328,19 @@ void dm_accept_partial_bio(struct bio *b 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;