kernel/git/stable/linux-stable.git/block/blk-flush.c, branch linux-6.5.y

blk-flush: fix rq->flush.seq for post-flush requests

2023-09-13T07:53:18+00:00

[ Upstream commit 28b241237470981a96fbd82077c8044466b61e5f ] If the policy == (REQ_FSEQ_DATA | REQ_FSEQ_POSTFLUSH), it means that the data sequence and post-flush sequence need to be done for this request. The rq->flush.seq should record what sequences have been done (or don't need to be done). So in this case, pre-flush doesn't need to be done, we should init rq->flush.seq to REQ_FSEQ_PREFLUSH not REQ_FSEQ_POSTFLUSH. Fixes: 615939a2ae73 ("blk-mq: defer to the normal submission path for post-flush requests") Signed-off-by: Chengming Zhou Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20230717040058.3993930-3-chengming.zhou@linux.dev Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

block: queue data commands from the flush state machine at the head

2023-07-14T14:42:58+00:00

We used to insert the data commands following a pre-flush to the head of the queue until commit 1e82fadfc6b ("blk-mq: do not do head insertions post-pre-flush commands"). Not doing this seems to cause hangs of such commands on NFS workloads when exported from file systems with SATA SSDs. I have no idea why this would starve these workloads, but doing a semantic revert of this patch (which looks quite different due to various other changes) fixes the hangs. Fixes: 1e82fadfc6b ("blk-mq: do not do head insertions post-pre-flush commands") Reported-by: Chuck Lever Signed-off-by: Christoph Hellwig Tested-by: Chuck Lever Link: https://lore.kernel.org/r/20230714143014.11879-1-hch@lst.de Signed-off-by: Jens Axboe

blk-mq: don't use the requeue list to queue flush commands

2023-05-20T01:52:42+00:00

Currently both requeues of commands that were already sent to the driver and flush commands submitted from the flush state machine share the same requeue_list struct request_queue, despite requeues doing head insertions and flushes not. Switch to using two separate lists instead. Signed-off-by: Christoph Hellwig Reviewed-by: Damien Le Moal Link: https://lore.kernel.org/r/20230519044050.107790-8-hch@lst.de Signed-off-by: Jens Axboe

blk-mq: do not do head insertions post-pre-flush commands

2023-05-20T01:52:29+00:00

blk_flush_complete_seq currently queues requests that write data after a pre-flush from the flush state machine at the head of the queue. This doesn't really make sense, as the original request bypassed all queue lists by directly diverting to blk_insert_flush from blk_mq_submit_bio. Signed-off-by: Christoph Hellwig Reviewed-by: Bart Van Assche Reviewed-by: Damien Le Moal Link: https://lore.kernel.org/r/20230519044050.107790-7-hch@lst.de Signed-off-by: Jens Axboe

blk-mq: defer to the normal submission path for post-flush requests

2023-05-20T01:52:29+00:00

Requests with the FUA bit on hardware without FUA support need a post flush before returning to the caller, but they can still be sent using the normal I/O path after initializing the flush-related fields and end I/O handler. Signed-off-by: Christoph Hellwig Reviewed-by: Bart Van Assche Link: https://lore.kernel.org/r/20230519044050.107790-6-hch@lst.de Signed-off-by: Jens Axboe

blk-mq: defer to the normal submission path for non-flush flush commands

2023-05-20T01:52:29+00:00

If blk_insert_flush decides that a command does not need to use the flush state machine, return false and let blk_mq_submit_bio handle it the normal way (including using an I/O scheduler) instead of doing a bypass insert. Signed-off-by: Christoph Hellwig Reviewed-by: Bart Van Assche Reviewed-by: Damien Le Moal Link: https://lore.kernel.org/r/20230519044050.107790-4-hch@lst.de Signed-off-by: Jens Axboe

blk-mq: reflow blk_insert_flush

2023-05-20T01:52:29+00:00

Use a switch statement to decide on the disposition of a flush request instead of multiple if statements, out of which one does checks that are more complex than required. Also warn on a malformed request early on instead of doing a BUG_ON later. Signed-off-by: Christoph Hellwig Reviewed-by: Damien Le Moal Reviewed-by: Bart Van Assche Link: https://lore.kernel.org/r/20230519044050.107790-3-hch@lst.de Signed-off-by: Jens Axboe

blk-mq: factor out a blk_rq_init_flush helper

2023-05-20T01:52:29+00:00

Factor out a helper from blk_insert_flush that initializes the flush machine related fields in struct request, and don't bother with the full memset as there's just a few fields to initialize, and all but one already have explicit initializers. Signed-off-by: Christoph Hellwig Reviewed-by: Damien Le Moal Reviewed-by: Bart Van Assche Link: https://lore.kernel.org/r/20230519044050.107790-2-hch@lst.de Signed-off-by: Jens Axboe

blk-mq: fix the blk_mq_add_to_requeue_list call in blk_kick_flush

2023-04-16T19:01:43+00:00

Commit b12e5c6c755a accidentally changes blk_kick_flush to do a head insert into the requeue list, fix this up. Fixes: b12e5c6c755a ("blk-mq: pass a flags argument to blk_mq_add_to_requeue_list") Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20230416073553.966161-1-hch@lst.de Signed-off-by: Jens Axboe

blk-mq: pass a flags argument to blk_mq_add_to_requeue_list

2023-04-13T12:52:30+00:00

Replace the boolean at_head argument with the same flags that are already passed to blk_mq_insert_request. Signed-off-by: Christoph Hellwig Reviewed-by: Damien Le Moal Link: https://lore.kernel.org/r/20230413064057.707578-21-hch@lst.de Signed-off-by: Jens Axboe