On 12/16/21 10:52 PM, Mariusz Tkaczyk 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/raid5.c | 34 ++++++++++++++++------------------
1 file changed, 16 insertions(+), 18 deletions(-)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 1240a5c16af8..8b5561811431 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -690,6 +690,9 @@ static int has_failed(struct r5conf *conf)
{
int degraded;
+ if (test_bit(MD_BROKEN, &conf->mddev->flags))
+ return 1;
+
if (conf->mddev->reshape_position == MaxSector)
return conf->mddev->degraded > conf->max_degraded;
@@ -2877,34 +2880,29 @@ static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
unsigned long flags;
pr_debug("raid456: error called\n");
- spin_lock_irqsave(&conf->device_lock, flags);
-
- 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
- */
- conf->recovery_disabled = mddev->recovery_disabled;
- spin_unlock_irqrestore(&conf->device_lock, flags);
- return;
- }
+ 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 (has_failed(conf)) {
+ set_bit(MD_BROKEN, &mddev->flags);
What about other callers of has_failed? Do they need to set BROKEN flag?
Or set the flag in has_failed if it returns true, just FYI.
Thanks,
Guoqing
