Currently if there is a leg failure, the bio will be put into the hold
list until userspace replace/remove the leg. Here we are trying to make
dm-raid1 ignore the failure and keep the following bios going on.
This is because there maybe a temporary path failure in clvmd
which leads to cluster raid1 remove/replace the fake device failure. And
it takes a long time to do the full sync if we readd the device back.
---
drivers/md/dm-raid1.c | 30 ++++++++++++++++++++++++++----
1 file changed, 26 insertions(+), 4 deletions(-)
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index 9584443..e237c42 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -24,7 +24,9 @@
#define MAX_RECOVERY 1 /* Maximum number of regions recovered in parallel. */
#define DM_RAID1_HANDLE_ERRORS 0x01
+#define DM_RAID1_KEEP_LOG 0x02
#define errors_handled(p) ((p)->features & DM_RAID1_HANDLE_ERRORS)
+#define keep_log(p) ((p)->features & DM_RAID1_KEEP_LOG)
static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped);
@@ -750,7 +752,7 @@ static void do_writes(struct mirror_set *ms, struct bio_list *writes)
dm_rh_delay(ms->rh, bio);
while ((bio = bio_list_pop(&nosync))) {
- if (unlikely(ms->leg_failure) && errors_handled(ms)) {
+ if (unlikely(ms->leg_failure) && errors_handled(ms) && !keep_log(ms)) {
spin_lock_irq(&ms->lock);
bio_list_add(&ms->failures, bio);
spin_unlock_irq(&ms->lock);
@@ -800,9 +802,19 @@ static void do_failures(struct mirror_set *ms, struct bio_list *failures)
* be wrong if the failed leg returned after reboot and
* got replicated back to the good legs.)
*/
- if (!get_valid_mirror(ms))
+
+ /*
+ * we return EIO when the log device is failed if keep_log is set
+ */
+ if (!get_valid_mirror(ms) || (keep_log(ms) && !ms->log_failure))
bio_endio(bio, -EIO);
- else if (errors_handled(ms))
+ /*
+ * After the userspace get noticed that the leg has failed,
+ * we just pretend that the bio has suceeded since the region
+ * has already been marked nosync. It's OK do the recovery after
+ * the device comes back
+ */
+ else if (errors_handled(ms) && !keep_log(ms))
hold_bio(ms, bio);
else
bio_endio(bio, 0);
@@ -1005,8 +1017,15 @@ static int parse_features(struct mirror_set *ms, unsigned argc, char **argv,
return -EINVAL;
}
+ argc--;
+ argv++;
(*args_used)++;
+ if (!strcmp("keep_log", argv[0])) {
+ ms->features |= DM_RAID1_KEEP_LOG;
+ (*args_used)++;
+ }
+
return 0;
}
@@ -1382,8 +1401,11 @@ static void mirror_status(struct dm_target *ti, status_type_t type,
DMEMIT(" %s %llu", ms->mirror[m].dev->name,
(unsigned long long)ms->mirror[m].offset);
- if (ms->features & DM_RAID1_HANDLE_ERRORS)
+ if (errors_handled(ms) && keep_log(ms))
+ DMEMIT(" 2 handle_errors keep_log");
+ else if (errors_handled(ms))
DMEMIT(" 1 handle_errors");
+
}
}
--
1.8.1.4
--
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