On Tue, Nov 08, 2022 at 02:55:38PM +0900, Damien Le Moal wrote:
> From: Christoph Hellwig <hch@xxxxxxxxxxxxx>
>
> Check that the PREFUSH and FUA flags are only set on write bios,
> given that the flush state machine expects that.
>
> Reported-by: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>
> Reviewed-by: Chaitanya Kulkarni <kch@xxxxxxxxxx>
> Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
> ---
> block/blk-core.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 17667159482e..d3446d38ba77 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -730,12 +730,15 @@ 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))
> goto end_io;
> + if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags)) {
Considering that blk_queue_write_cache() looks like this:
void blk_queue_write_cache(struct request_queue *q, bool wc, bool fua)
{
if (wc)
blk_queue_flag_set(QUEUE_FLAG_WC, q);
else
blk_queue_flag_clear(QUEUE_FLAG_WC, q);
if (fua)
blk_queue_flag_set(QUEUE_FLAG_FUA, q);
else
blk_queue_flag_clear(QUEUE_FLAG_FUA, q);
wbt_set_write_cache(q, test_bit(QUEUE_FLAG_WC, &q->queue_flags));
}
It seems that you can have flag WC set, without having flag FUA set.
So should perhaps the line:
> + if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags)) {
instead be:
if (!test_bit(QUEUE_FLAG_FUA, &q->queue_flags)) {
Kind regards,
Niklas
