This is a note to let you know that I've just added the patch titled
md/raid1: be more cautious where we read-balance during resync.
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
md-raid1-be-more-cautious-where-we-read-balance-during-resync.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c6d119cf1b5a778e9ed60a006e2a434fcc4471a2 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@xxxxxxx>
Date: Tue, 9 Sep 2014 13:49:46 +1000
Subject: md/raid1: be more cautious where we read-balance during resync.
From: NeilBrown <neilb@xxxxxxx>
commit c6d119cf1b5a778e9ed60a006e2a434fcc4471a2 upstream.
commit 79ef3a8aa1cb1523cc231c9a90a278333c21f761 made
it possible for reads to happen concurrently with resync.
This means that we need to be more careful where read_balancing
is allowed during resync - we can no longer be sure that any
resync that has already started will definitely finish.
So keep read_balancing to before recovery_cp, which is conservative
but safe.
This bug makes it possible to read from a device that doesn't
have up-to-date data, so it can cause data corruption.
So it is suitable for any kernel since 3.11.
Fixes: 79ef3a8aa1cb1523cc231c9a90a278333c21f761
Signed-off-by: NeilBrown <neilb@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/raid1.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -540,11 +540,7 @@ static int read_balance(struct r1conf *c
has_nonrot_disk = 0;
choose_next_idle = 0;
- if (conf->mddev->recovery_cp < MaxSector &&
- (this_sector + sectors >= conf->next_resync))
- choose_first = 1;
- else
- choose_first = 0;
+ choose_first = (conf->mddev->recovery_cp < this_sector + sectors);
for (disk = 0 ; disk < conf->raid_disks * 2 ; disk++) {
sector_t dist;
Patches currently in stable-queue which might be from neilb@xxxxxxx are
queue-3.14/md-raid1-fix_read_error-should-act-on-all-non-faulty-devices.patch
queue-3.14/md-raid1-count-resync-requests-in-nr_pending.patch
queue-3.14/md-raid1-update-next_resync-under-resync_lock.patch
queue-3.14/md-raid1-intialise-start_next_window-for-read-case-to-avoid-hang.patch
queue-3.14/md-raid1-don-t-use-next_resync-to-determine-how-far-resync-has-progressed.patch
queue-3.14/md-raid1-be-more-cautious-where-we-read-balance-during-resync.patch
queue-3.14/md-raid1-make-sure-resync-waits-for-conflicting-writes-to-complete.patch
queue-3.14/md-raid1-clean-up-request-counts-properly-in-close_sync.patch
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