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authorNeilBrown <neilb@suse.de>2014-09-10 15:01:49 +1000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-10-05 14:52:23 -0700
commit9dcea9a8c1440e9db950634c89030f511704dfe0 (patch)
parent849815fe007950418ee816d1e8c7c6ce26233a07 (diff)
md/raid1: make sure resync waits for conflicting writes to complete.
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@gmail.com> Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 65afd8aa6608..86753358ea46 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -845,10 +845,12 @@ static void raise_barrier(struct r1conf *conf)
* 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.
!conf->array_frozen &&
conf->barrier < RESYNC_DEPTH &&
+ conf->current_window_requests == 0 &&
(conf->start_next_window >=
conf->next_resync + RESYNC_SECTORS),
@@ -915,8 +917,8 @@ static sector_t wait_barrier(struct r1conf *conf, struct bio *bio)
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 +