block: fix partial zone append completion handling in req_bio_endio()

Partial completions of zone append request is not allowed but if a zone
append completion indicates a number of completed bytes different from
the original BIO size, only the BIO status is set to error. This leads
to bio_advance() not setting the BIO size to 0 and thus to not call
bio_endio() at the end of req_bio_endio().

Make sure a partially completed zone append is failed and completed
immediately by forcing the completed number of bytes (nbytes) to be
equal to the BIO size, thus ensuring that bio_endio() is called.

Fixes: 297db731847e ("block: fix req_bio_endio append error handling")
Cc: stable@kernel.vger.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20240110092942.442334-1-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index fb29ff5..aa9a05f 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -772,11 +772,16 @@ static void req_bio_endio(struct request *rq, struct bio *bio,
                /*
                 * Partial zone append completions cannot be supported as the
                 * BIO fragments may end up not being written sequentially.
+                * For such case, force the completed nbytes to be equal to
+                * the BIO size so that bio_advance() sets the BIO remaining
+                * size to 0 and we end up calling bio_endio() before returning.
                 */
-               if (bio->bi_iter.bi_size != nbytes)
+               if (bio->bi_iter.bi_size != nbytes) {
                        bio->bi_status = BLK_STS_IOERR;
-               else
+                       nbytes = bio->bi_iter.bi_size;
+               } else {
                        bio->bi_iter.bi_sector = rq->__sector;
+               }
        }
 
        bio_advance(bio, nbytes);