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md/raid1: Fix data corruption for degraded array with slow disk

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read_balance() will avoid reading from slow disks as much as possible,
however, if valid data only lands in slow disks, and a new normal disk
is still in recovery, unrecovered data can be read:

raid1_read_request
 read_balance
  raid1_should_read_first
  -> return false
  choose_best_rdev
  -> normal disk is not recovered, return -1
  choose_bb_rdev
  -> missing the checking of recovery, return the normal disk
 -> read unrecovered data

Root cause is that the checking of recovery is missing in
choose_bb_rdev(). Hence add such checking to fix the problem.

Also fix similar problem in choose_slow_rdev().

Cc: stable@vger.kernel.org
Fixes: 9f3ced7922 ("md/raid1: factor out choose_bb_rdev() from read_balance()")
Fixes: dfa8ecd167 ("md/raid1: factor out choose_slow_rdev() from read_balance()")
Reported-and-tested-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Closes: https://lore.kernel.org/all/9952f532-2554-44bf-b906-4880b2e88e3a@o2.pl/
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20240803091137.3197008-1-yukuai1@huaweicloud.com
Signed-off-by: Song Liu <song@kernel.org>
This commit is contained in:
Yu Kuai 2024-08-03 17:11:37 +08:00 committed by Song Liu
parent 7db4042336
commit c916ca3530
1 changed files with 10 additions and 4 deletions
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14
drivers/md/raid1.c
View file

@ -617,6 +617,12 @@ static int choose_first_rdev(struct r1conf *conf, struct r1bio *r1_bio,
return -1;
}
static bool rdev_in_recovery(struct md_rdev *rdev, struct r1bio *r1_bio)
{
return !test_bit(In_sync, &rdev->flags) &&
rdev->recovery_offset < r1_bio->sector + r1_bio->sectors;
}
static int choose_bb_rdev(struct r1conf *conf, struct r1bio *r1_bio,
int *max_sectors)
{
@ -635,6 +641,7 @@ static int choose_bb_rdev(struct r1conf *conf, struct r1bio *r1_bio,
rdev = conf->mirrors[disk].rdev;
if (!rdev || test_bit(Faulty, &rdev->flags) ||
rdev_in_recovery(rdev, r1_bio) ||
test_bit(WriteMostly, &rdev->flags))
continue;
@ -673,7 +680,8 @@ static int choose_slow_rdev(struct r1conf *conf, struct r1bio *r1_bio,
rdev = conf->mirrors[disk].rdev;
if (!rdev || test_bit(Faulty, &rdev->flags) ||
!test_bit(WriteMostly, &rdev->flags))
!test_bit(WriteMostly, &rdev->flags) ||
rdev_in_recovery(rdev, r1_bio))
continue;
/* there are no bad blocks, we can use this disk */
@ -733,9 +741,7 @@ static bool rdev_readable(struct md_rdev *rdev, struct r1bio *r1_bio)
if (!rdev || test_bit(Faulty, &rdev->flags))
return false;
/* still in recovery */
if (!test_bit(In_sync, &rdev->flags) &&
rdev->recovery_offset < r1_bio->sector + r1_bio->sectors)
if (rdev_in_recovery(rdev, r1_bio))
return false;
/* don't read from slow disk unless have to */