Commit 143f6e73 authored Jul 08, 2019 by Xiao Ni Committed by Song Liu Aug 07, 2019

md/raid6: Set R5_ReadError when there is read failure on parity disk



7471fb77 ("md/raid6: Fix anomily when recovering a single device in
RAID6.") avoids rereading P when it can be computed from other members.
However, this misses the chance to re-write the right data to P. This
patch sets R5_ReadError if the re-read fails.

Also, when re-read is skipped, we also missed the chance to reset
rdev->read_errors to 0. It can fail the disk when there are many read
errors on P member disk (other disks don't have read error)

V2: upper layer read request don't read parity/Q data. So there is no
need to consider such situation.

This is Reported-by: kbuild test robot <lkp@intel.com>

Fixes: 7471fb77 ("md/raid6: Fix anomily when recovering a single device in RAID6.")
Cc: <stable@vger.kernel.org> #4.4+
Signed-off-by: Xiao Ni <xni@redhat.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

parent 4675719d

drivers/md/raid5.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -2558,7 +2558,9 @@ static void raid5_end_read_request(struct bio * bi)
		&& !test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
		retry = 1;
		if (retry)
		if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
		if (sh->qd_idx >= 0 && sh->pd_idx == i)
		set_bit(R5_ReadError, &sh->dev[i].flags);
		else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
		set_bit(R5_ReadError, &sh->dev[i].flags);
		clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
		} else

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