On Thu, Jan 27, 2022 at 11:39 PM Mariusz Tkaczyk
<mariusz.tkaczyk@xxxxxxxxxxxxxxx> wrote:
>
> Raid456 module had allowed to achieve failed state. It was fixed by
> fb73b357fb9 ("raid5: block failing device if raid will be failed").
> This fix introduces a bug, now if raid5 fails during IO, it may result
> with a hung task without completion. Faulty flag on the device is
> necessary to process all requests and is checked many times, mainly in
> analyze_stripe().
> Allow to set faulty on drive again and set MD_BROKEN if raid is failed.
>
> As a result, this level is allowed to achieve failed state again, but
> communication with userspace (via -EBUSY status) will be preserved.
>
> This restores possibility to fail array via #mdadm --set-faulty command
> and will be fixed by additional verification on mdadm side.
>
> Reproduction steps:
> mdadm -CR imsm -e imsm -n 3 /dev/nvme[0-2]n1
> mdadm -CR r5 -e imsm -l5 -n3 /dev/nvme[0-2]n1 --assume-clean
> mkfs.xfs /dev/md126 -f
> mount /dev/md126 /mnt/root/
>
> fio --filename=/mnt/root/file --size=5GB --direct=1 --rw=randrw
> --bs=64k --ioengine=libaio --iodepth=64 --runtime=240 --numjobs=4
> --time_based --group_reporting --name=throughput-test-job
> --eta-newline=1 &
>
> echo 1 > /sys/block/nvme2n1/device/device/remove
> echo 1 > /sys/block/nvme1n1/device/device/remove
>
> [ 1475.787779] Call Trace:
> [ 1475.793111] __schedule+0x2a6/0x700
> [ 1475.799460] schedule+0x38/0xa0
> [ 1475.805454] raid5_get_active_stripe+0x469/0x5f0 [raid456]
> [ 1475.813856] ? finish_wait+0x80/0x80
> [ 1475.820332] raid5_make_request+0x180/0xb40 [raid456]
> [ 1475.828281] ? finish_wait+0x80/0x80
> [ 1475.834727] ? finish_wait+0x80/0x80
> [ 1475.841127] ? finish_wait+0x80/0x80
> [ 1475.847480] md_handle_request+0x119/0x190
> [ 1475.854390] md_make_request+0x8a/0x190
> [ 1475.861041] generic_make_request+0xcf/0x310
> [ 1475.868145] submit_bio+0x3c/0x160
> [ 1475.874355] iomap_dio_submit_bio.isra.20+0x51/0x60
> [ 1475.882070] iomap_dio_bio_actor+0x175/0x390
> [ 1475.889149] iomap_apply+0xff/0x310
> [ 1475.895447] ? iomap_dio_bio_actor+0x390/0x390
> [ 1475.902736] ? iomap_dio_bio_actor+0x390/0x390
> [ 1475.909974] iomap_dio_rw+0x2f2/0x490
> [ 1475.916415] ? iomap_dio_bio_actor+0x390/0x390
> [ 1475.923680] ? atime_needs_update+0x77/0xe0
> [ 1475.930674] ? xfs_file_dio_aio_read+0x6b/0xe0 [xfs]
> [ 1475.938455] xfs_file_dio_aio_read+0x6b/0xe0 [xfs]
> [ 1475.946084] xfs_file_read_iter+0xba/0xd0 [xfs]
> [ 1475.953403] aio_read+0xd5/0x180
> [ 1475.959395] ? _cond_resched+0x15/0x30
> [ 1475.965907] io_submit_one+0x20b/0x3c0
> [ 1475.972398] __x64_sys_io_submit+0xa2/0x180
> [ 1475.979335] ? do_io_getevents+0x7c/0xc0
> [ 1475.986009] do_syscall_64+0x5b/0x1a0
> [ 1475.992419] entry_SYSCALL_64_after_hwframe+0x65/0xca
> [ 1476.000255] RIP: 0033:0x7f11fc27978d
> [ 1476.006631] Code: Bad RIP value.
> [ 1476.073251] INFO: task fio:3877 blocked for more than 120 seconds.
>
> Fixes: fb73b357fb9 ("raid5: block failing device if raid will be failed")
> Signed-off-by: Mariusz Tkaczyk <mariusz.tkaczyk@xxxxxxxxxxxxxxx>
> ---
> drivers/md/raid1.c | 1 +
> drivers/md/raid5.c | 49 +++++++++++++++++++++++-----------------------
> 2 files changed, 25 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
> index b222bafa1196..58c8eddb0f55 100644
> --- a/drivers/md/raid1.c
> +++ b/drivers/md/raid1.c
> @@ -1627,6 +1627,7 @@ static void raid1_status(struct seq_file *seq, struct mddev *mddev)
> * - if is on @rdev is removed.
> * - if is off, @rdev is not removed, but recovery from it is disabled (@rdev is
> * very likely to fail).
> + *
type error? If not, it should be better in the second patch.
Regards
Xiao
> * In both cases, &MD_BROKEN will be set in &mddev->flags.
> */
> static void raid1_error(struct mddev *mddev, struct md_rdev *rdev)
> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> index 1240a5c16af8..bee953c8007f 100644
> --- a/drivers/md/raid5.c
> +++ b/drivers/md/raid5.c
> @@ -686,17 +686,21 @@ int raid5_calc_degraded(struct r5conf *conf)
> return degraded;
> }
>
> -static int has_failed(struct r5conf *conf)
> +static bool has_failed(struct r5conf *conf)
> {
> - int degraded;
> + int degraded = conf->mddev->degraded;
>
> - if (conf->mddev->reshape_position == MaxSector)
> - return conf->mddev->degraded > conf->max_degraded;
> + if (test_bit(MD_BROKEN, &conf->mddev->flags))
> + return true;
>
> - degraded = raid5_calc_degraded(conf);
> - if (degraded > conf->max_degraded)
> - return 1;
> - return 0;
> + if (conf->mddev->reshape_position != MaxSector)
> + degraded = raid5_calc_degraded(conf);
> +
> + if (degraded > conf->max_degraded) {
> + set_bit(MD_BROKEN, &conf->mddev->flags);
> + return true;
> + }
> + return false;
> }
>
> struct stripe_head *
> @@ -2877,34 +2881,29 @@ static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
> unsigned long flags;
> pr_debug("raid456: error called\n");
>
> + pr_crit("md/raid:%s: Disk failure on %s, disabling device.\n",
> + mdname(mddev), bdevname(rdev->bdev, b));
> +
> spin_lock_irqsave(&conf->device_lock, flags);
> + set_bit(Faulty, &rdev->flags);
> + clear_bit(In_sync, &rdev->flags);
> + mddev->degraded = raid5_calc_degraded(conf);
>
> - if (test_bit(In_sync, &rdev->flags) &&
> - mddev->degraded == conf->max_degraded) {
> - /*
> - * Don't allow to achieve failed state
> - * Don't try to recover this device
> - */
> + if (has_failed(conf)) {
> conf->recovery_disabled = mddev->recovery_disabled;
> - spin_unlock_irqrestore(&conf->device_lock, flags);
> - return;
> + pr_crit("md/raid:%s: Cannot continue operation (%d/%d failed).\n",
> + mdname(mddev), mddev->degraded, conf->raid_disks);
> + } else {
> + pr_crit("md/raid:%s: Operation continuing on %d devices.\n",
> + mdname(mddev), conf->raid_disks - mddev->degraded);
> }
>
> - set_bit(Faulty, &rdev->flags);
> - clear_bit(In_sync, &rdev->flags);
> - mddev->degraded = raid5_calc_degraded(conf);
> spin_unlock_irqrestore(&conf->device_lock, flags);
> set_bit(MD_RECOVERY_INTR, &mddev->recovery);
>
> set_bit(Blocked, &rdev->flags);
> set_mask_bits(&mddev->sb_flags, 0,
> BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
> - pr_crit("md/raid:%s: Disk failure on %s, disabling device.\n"
> - "md/raid:%s: Operation continuing on %d devices.\n",
> - mdname(mddev),
> - bdevname(rdev->bdev, b),
> - mdname(mddev),
> - conf->raid_disks - mddev->degraded);
> r5c_update_on_rdev_error(mddev, rdev);
> }
>
> --
> 2.26.2
>
