block: Ignore REQ_NOWAIT for zone reset and zone finish operations

There are currently any issuer of REQ_OP_ZONE_RESET and
REQ_OP_ZONE_FINISH operations that set REQ_NOWAIT. However, as we cannot
handle this flag correctly due to the potential request allocation
failure that may happen in blk_mq_submit_bio() after blk_zone_plug_bio()
has handled the zone write plug write pointer updates for the targeted
zones, modify blk_zone_wplug_handle_reset_or_finish() to warn if this
flag is set and ignore it.

Fixes: dd291d77cc90 ("block: Introduce zone write plugging")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20241209122357.47838-3-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 7982b9494d633b42337b1bbf0fee84ca49f15c71..ee9c67121c6c8781dcf64ae2c61dba43d43b0d65 100644 (file)
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -707,6 +707,15 @@ static bool blk_zone_wplug_handle_reset_or_finish(struct bio *bio,
                return true;
        }
 
+       /*
+        * No-wait reset or finish BIOs do not make much sense as the callers
+        * issue these as blocking operations in most cases. To avoid issues
+        * the BIO execution potentially failing with BLK_STS_AGAIN, warn about
+        * REQ_NOWAIT being set and ignore that flag.
+        */
+       if (WARN_ON_ONCE(bio->bi_opf & REQ_NOWAIT))
+               bio->bi_opf &= ~REQ_NOWAIT;
+
        /*
         * If we have a zone write plug, set its write pointer offset to 0
         * (reset case) or to the zone size (finish case). This will abort all