Yu Kuai 2febf5fdbf md/raid1: Fix data corruption for degraded array with slow disk
commit c916ca3530 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-08-29 17:35:40 +02:00
2024-08-19 06:05:40 +02:00

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