block: add a sanity check for non-write flush/fua bios

Check that the PREFUSH and FUA flags are only set on write bios,
given that the flush state machine expects that.

[Damien] The check is also extended to REQ_OP_ZONE_APPEND operations as
these are data write operations used by btrfs and zonefs and may also
have the REQ_FUA bit set.

Reported-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Niklas Cassel <niklas.cassel@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>

diff --git a/block/blk-core.c b/block/blk-core.c
index 9321767470dc5f5b3bcfd2939851a15a6dffe2c2..c644aac498ef9b27b5d19e762ed0163372f958f2 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -744,12 +744,16 @@ void submit_bio_noacct(struct bio *bio)
         * Filter flush bio's early so that bio based drivers without flush
         * support don't have to worry about them.
         */
-       if (op_is_flush(bio->bi_opf) &&
-           !test_bit(QUEUE_FLAG_WC, &q->queue_flags)) {
-               bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA);
-               if (!bio_sectors(bio)) {
-                       status = BLK_STS_OK;
+       if (op_is_flush(bio->bi_opf)) {
+               if (WARN_ON_ONCE(bio_op(bio) != REQ_OP_WRITE &&
+                                bio_op(bio) != REQ_OP_ZONE_APPEND))
                        goto end_io;
+               if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags)) {
+                       bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA);
+                       if (!bio_sectors(bio)) {
+                               status = BLK_STS_OK;
+                               goto end_io;
+                       }
                }
        }