On 11/03/2017 12:58 PM, Chris Walker wrote:

Hello,
I was looking at this again today and it appears that with this change, error handling no longer works correctly in RAID10 (I haven't checked the other levels yet).  Without a BBL configured, an error cycles through fix_read_error until max_read_errors is exceeded, and only then is the drive kicked out of the array.  For example, if I inject errors in response to both read and write commands at sector 16392 of /dev/sda, logs in response to a read of the corresponding md0 sector look like:
 
(many repeats)
Oct 27 16:15:16 c1 kernel: md/raid10:md0: unable to read back corrected sectors (8 sectors at 16392 on sda)
Oct 27 16:15:16 c1 kernel: md/raid10:md0: sda: failing drive
Oct 27 16:15:16 c1 kernel: md/raid10:md0: read correction write failed (8 sectors at 16392 on sda)
Oct 27 16:15:16 c1 kernel: md/raid10:md0: sda: failing drive
Oct 27 16:15:16 c1 kernel: md/raid10:md0: unable to read back corrected sectors (8 sectors at 16392 on sda)
Oct 27 16:15:16 c1 kernel: md/raid10:md0: sda: failing drive
Oct 27 16:15:16 c1 kernel: md/raid10:md0: sda: Raid device exceeded read_error threshold [cur 21:max 20]
Oct 27 16:15:16 c1 kernel: md/raid10:md0: sda: Failing raid device
Oct 27 16:15:16 c1 kernel: md/raid10:md0: Disk failure on sda, disabling device.

Previously, the drive would have been failed out of the array by the call of md_error at the end of r10_sync_page_io.

Is there an appetite for a patch that takes the easy way out by reverting to the previous behavior with changes like

-       if (!rdev_set_badblocks(rdev, sector, sectors, 0))
+       if (!rdev_set_badblocks(rdev, sector, sectors, 0) || rdev->badblocks.shift < 0)

Thanks,
Chris

As a RAID10 user that seems like the right thing to do, thank you.

--Sarah