On Sat, Dec 25, 2021 at 2:13 PM Vishal Verma <vverma@xxxxxxxxxxxxxxxx> wrote:
>
>
> On 12/25/21 12:28 AM, Vishal Verma wrote:
> >
> >
> > On 12/24/21 7:14 PM, Song Liu wrote:
> >> On Tue, Dec 21, 2021 at 12:06 PM Vishal Verma<vverma@xxxxxxxxxxxxxxxx> wrote:
> >>> Returns EAGAIN in case the raid456 driver would block
> >>> waiting for situations like:
> >>>
> >>> - Reshape operation,
> >>> - Discard operation.
> >>>
> >>> Signed-off-by: Vishal Verma<vverma@xxxxxxxxxxxxxxxx>
> >> I think we will need the following fix for raid456:
> > Ack
> >> ============================ 8< ============================
> >>
> >> diff --git i/drivers/md/raid5.c w/drivers/md/raid5.c
> >> index 6ab22f29dacd..55d372ce3300 100644
> >> --- i/drivers/md/raid5.c
> >> +++ w/drivers/md/raid5.c
> >> @@ -5717,6 +5717,7 @@ static void make_discard_request(struct mddev
> >> *mddev, struct bio *bi)
> >> raid5_release_stripe(sh);
> >> /* Bail out if REQ_NOWAIT is set */
> >> if (bi->bi_opf & REQ_NOWAIT) {
> >> + finish_wait(&conf->wait_for_overlap, &w);
> >> bio_wouldblock_error(bi);
> >> return;
> >> }
> >> @@ -5734,6 +5735,7 @@ static void make_discard_request(struct mddev
> >> *mddev, struct bio *bi)
> >> raid5_release_stripe(sh);
> >> /* Bail out if REQ_NOWAIT is set */
> >> if (bi->bi_opf & REQ_NOWAIT) {
> >> +
> >> finish_wait(&conf->wait_for_overlap, &w);
> >> bio_wouldblock_error(bi);
> >> return;
> >> }
> >> @@ -5829,7 +5831,6 @@ static bool raid5_make_request(struct mddev
> >> *mddev, struct bio * bi)
> >> last_sector = bio_end_sector(bi);
> >> bi->bi_next = NULL;
> >>
> >> - md_account_bio(mddev, &bi);
> >> /* Bail out if REQ_NOWAIT is set */
> >> if ((bi->bi_opf & REQ_NOWAIT) &&
> >> (conf->reshape_progress != MaxSector) &&
> >> @@ -5837,9 +5838,11 @@ static bool raid5_make_request(struct mddev
> >> *mddev, struct bio * bi)
> >> ? (logical_sector > conf->reshape_progress &&
> >> logical_sector <= conf->reshape_safe)
> >> : (logical_sector >= conf->reshape_safe && logical_sector
> >> < conf->reshape_progress))) {
> >> bio_wouldblock_error(bi);
> >> + if (rw == WRITE)
> >> + md_write_end(mddev);
> >> return true;
> >> }
> >> -
> >> + md_account_bio(mddev, &bi);
> >> prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
> >> for (; logical_sector < last_sector; logical_sector +=
> >> RAID5_STRIPE_SECTORS(conf)) {
> >> int previous;
> >>
> >> ============================ 8< ============================
> >>
> >> Vishal, please try to trigger all these conditions (including raid1,
> >> raid10) and make sure
> >> they work properly.
> >>
> >> For example, I triggered raid5 reshape and used something like the
> >> following to make
> >> sure the logic is triggered:
> >>
> >> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> >> index 55d372ce3300..e79de48a0027 100644
> >> --- a/drivers/md/raid5.c
> >> +++ b/drivers/md/raid5.c
> >> @@ -5840,6 +5840,11 @@ static bool raid5_make_request(struct mddev
> >> *mddev, struct bio * bi)
> >> bio_wouldblock_error(bi);
> >> if (rw == WRITE)
> >> md_write_end(mddev);
> >> + {
> >> + static int count = 0;
> >> + if (count++ < 10)
> >> + pr_info("%s REQ_NOWAIT return\n", __func__);
> >> + }
> >> return true;
> >> }
> >> md_account_bio(mddev, &bi);
> >>
> >> Thanks,
> >> Song
> >>
> > Sure, will try this and verify for raid1/10.
Please also try test raid5 with discard. I haven't tested those two
conditions yet.
> I am running into an issue during raid10 reshape. I can see the nowait
> code getting triggered during reshape, but it seems like the reshape
> operation was stuck as soon as I issued write IO using FIO to the array
> during reshape.
> FIO also seem stuck i.e no IO went through...
Maybe the following could fix it?
Thanks,
Song
diff --git i/drivers/md/raid10.c w/drivers/md/raid10.c
index e2c524d50ec0..291eceaeb26c 100644
--- i/drivers/md/raid10.c
+++ w/drivers/md/raid10.c
@@ -1402,14 +1402,14 @@ static void raid10_write_request(struct mddev
*mddev, struct bio *bio,
: (bio->bi_iter.bi_sector + sectors > conf->reshape_safe &&
bio->bi_iter.bi_sector < conf->reshape_progress))) {
/* Need to update reshape_position in metadata */
- mddev->reshape_position = conf->reshape_progress;
- set_mask_bits(&mddev->sb_flags, 0,
- BIT(MD_SB_CHANGE_DEVS) |
BIT(MD_SB_CHANGE_PENDING));
- md_wakeup_thread(mddev->thread);
if (bio->bi_opf & REQ_NOWAIT) {
bio_wouldblock_error(bio);
return;
}
+ mddev->reshape_position = conf->reshape_progress;
+ set_mask_bits(&mddev->sb_flags, 0,
+ BIT(MD_SB_CHANGE_DEVS) |
BIT(MD_SB_CHANGE_PENDING));
+ md_wakeup_thread(mddev->thread);
raid10_log(conf->mddev, "wait reshape metadata");
wait_event(mddev->sb_wait,
!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags));
