3.13.11.9 -stable review patch. If anyone has any objections, please let me know.
------------------ From: NeilBrown <[email protected]> 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 <[email protected]> Signed-off-by: NeilBrown <[email protected]> [ kamal: backport to 3.13-stable: no bi_iter struct ] Signed-off-by: Kamal Mostafa <[email protected]> --- drivers/md/raid1.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 2414a79..c85ac43 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -847,10 +847,12 @@ 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. */ 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); @@ -917,8 +919,8 @@ 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_sector) { + if (bio->bi_sector >= + conf->next_resync) { if (conf->start_next_window == MaxSector) conf->start_next_window = conf->next_resync + -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
