This is a note to let you know that I've just added the patch titled
md/raid1: make sure resync waits for conflicting writes to complete.
to the 3.16-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-make-sure-resync-waits-for-conflicting-writes-to-complete.patch
and it can be found in the queue-3.16 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2f73d3c55d09ce60647b96ad2a9b539c95a530ee Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@xxxxxxx>
Date: Wed, 10 Sep 2014 15:01:49 +1000
Subject: md/raid1: make sure resync waits for conflicting writes to complete.
From: NeilBrown <neilb@xxxxxxx>
commit 2f73d3c55d09ce60647b96ad2a9b539c95a530ee upstream.
The resync/recovery process for raid1 was recently changed
so that writes could happen in parallel with resync providing
they were in different regions of the device.
There is a problem though: While a write request will always
wait for conflicting resync to complete, a resync request
will *not* always wait for conflicting writes to complete.
Two changes are needed to fix this:
1/ raise_barrier (which waits until it is safe to do resync)
must wait until current_window_requests is zero
2/ wait_battier (which waits at the start of a new write request)
must update current_window_requests if the request could
possible conflict with a concurrent resync.
As concurrent writes and resync can lead to data loss,
this patch is suitable for -stable.
Fixes: 79ef3a8aa1cb1523cc231c9a90a278333c21f761
Cc: majianpeng <majianpeng@xxxxxxxxx>
Signed-off-by: NeilBrown <neilb@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/raid1.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -845,10 +845,12 @@ static void raise_barrier(struct r1conf
* C: next_resync + RESYNC_SECTORS > start_next_window, meaning
* next resync will reach to the window which normal bios are
* handling.
+ * D: while there are any active requests in the current window.
*/
wait_event_lock_irq(conf->wait_barrier,
!conf->array_frozen &&
conf->barrier < RESYNC_DEPTH &&
+ conf->current_window_requests == 0 &&
(conf->start_next_window >=
conf->next_resync + RESYNC_SECTORS),
conf->resync_lock);
@@ -915,8 +917,8 @@ static sector_t wait_barrier(struct r1co
}
if (bio && bio_data_dir(bio) == WRITE) {
- if (conf->next_resync + NEXT_NORMALIO_DISTANCE
- <= bio->bi_iter.bi_sector) {
+ if (bio->bi_iter.bi_sector >=
+ conf->next_resync) {
if (conf->start_next_window == MaxSector)
conf->start_next_window =
conf->next_resync +
Patches currently in stable-queue which might be from neilb@xxxxxxx are
queue-3.16/md-raid1-fix_read_error-should-act-on-all-non-faulty-devices.patch
queue-3.16/md-raid1-count-resync-requests-in-nr_pending.patch
queue-3.16/md-raid1-update-next_resync-under-resync_lock.patch
queue-3.16/md-raid1-intialise-start_next_window-for-read-case-to-avoid-hang.patch
queue-3.16/md-raid1-don-t-use-next_resync-to-determine-how-far-resync-has-progressed.patch
queue-3.16/md-raid1-be-more-cautious-where-we-read-balance-during-resync.patch
queue-3.16/md-raid1-make-sure-resync-waits-for-conflicting-writes-to-complete.patch
queue-3.16/md-raid1-clean-up-request-counts-properly-in-close_sync.patch
--
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