From: Mikulas Patocka Hold all write bios when leg fails and errors are handled When using a userspace daemon such as dmeventd to handle errors, we must delay completing bios until it has done its job. This patch prevents the following race: - primary leg fails - write "1" fail, the write is held, secondary leg is set default - write "2" goes straight to the secondary leg Signed-off-by: Mikulas Patocka Reviewed-by: Takahiro Yasui Tested-by: Takahiro Yasui Signed-off-by: Alasdair G Kergon --- drivers/md/dm-raid1.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) Index: linux-2.6.32/drivers/md/dm-raid1.c =================================================================== --- linux-2.6.32.orig/drivers/md/dm-raid1.c +++ linux-2.6.32/drivers/md/dm-raid1.c @@ -69,6 +69,7 @@ struct mirror_set { region_t nr_regions; int in_sync; int log_failure; + int leg_failure; atomic_t suspend; atomic_t default_mirror; /* Default mirror */ @@ -211,6 +212,8 @@ static void fail_mirror(struct mirror *m struct mirror_set *ms = m->ms; struct mirror *new; + ms->leg_failure = 1; + /* * error_count is used for nothing more than a * simple way to tell if a device has encountered @@ -734,8 +737,12 @@ static void do_writes(struct mirror_set dm_rh_delay(ms->rh, bio); while ((bio = bio_list_pop(&nosync))) { - map_bio(get_default_mirror(ms), bio); - generic_make_request(bio); + if (unlikely(ms->leg_failure) && errors_handled(ms)) + hold_bio(ms, bio); + else { + map_bio(get_default_mirror(ms), bio); + generic_make_request(bio); + } } } @@ -848,6 +855,7 @@ static struct mirror_set *alloc_context( ms->nr_regions = dm_sector_div_up(ti->len, region_size); ms->in_sync = 0; ms->log_failure = 0; + ms->leg_failure = 0; atomic_set(&ms->suspend, 0); atomic_set(&ms->default_mirror, DEFAULT_MIRROR);