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.
This patch merges the former five small patches to implement this
feature. The userspace should pass "keep_log" into kernel to make this feature to
take effect when creating dm-raid1, same as "handle_errors".
Signed-off-by: Lidong Zhong <lzhong@xxxxxxxx>
Tested-by: Liuhua Wang <lwang@xxxxxxxx>
---
drivers/md/dm-raid1.c | 62 ++++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 49 insertions(+), 13 deletions(-)
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index 089d627..3de48d1 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);
@@ -229,7 +231,7 @@ static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type)
if (m != get_default_mirror(ms))
goto out;
- if (!ms->in_sync) {
+ if (!ms->in_sync && !keep_log(ms)) {
/*
* Better to issue requests to same failing device
* than to risk returning corrupt data.
@@ -370,6 +372,17 @@ static int recover(struct mirror_set *ms, struct dm_region *reg)
return r;
}
+static void reset_ms_flags(struct mirror_set *ms)
+{
+ unsigned int m;
+
+ ms->leg_failure = 0;
+ for (m = 0; m < ms->nr_mirrors; m++) {
+ atomic_set(&(ms->mirror[m].error_count), 0);
+ ms->mirror[m].error_type = 0;
+ }
+}
+
static void do_recovery(struct mirror_set *ms)
{
struct dm_region *reg;
@@ -398,6 +411,7 @@ static void do_recovery(struct mirror_set *ms)
/* the sync is complete */
dm_table_event(ms->ti->table);
ms->in_sync = 1;
+ reset_ms_flags(ms);
}
}
@@ -759,7 +773,7 @@ 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);
@@ -809,9 +823,21 @@ 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 there's no valid mirror legs
+ * -or-
+ * the log device is failed if keep_log is set
+ */
+ if (unlikely(!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);
@@ -987,6 +1013,7 @@ static int parse_features(struct mirror_set *ms, unsigned argc, char **argv,
unsigned num_features;
struct dm_target *ti = ms->ti;
char dummy;
+ int i;
*args_used = 0;
@@ -1007,14 +1034,20 @@ static int parse_features(struct mirror_set *ms, unsigned argc, char **argv,
return -EINVAL;
}
- if (!strcmp("handle_errors", argv[0]))
- ms->features |= DM_RAID1_HANDLE_ERRORS;
- else {
- ti->error = "Unrecognised feature requested";
- return -EINVAL;
- }
+ for (i = 0; i < num_features; i++) {
+ if (!strcmp("handle_errors", argv[0]))
+ ms->features |= DM_RAID1_HANDLE_ERRORS;
+ else if (!strcmp("keep_log", argv[0]))
+ ms->features |= DM_RAID1_KEEP_LOG;
+ else {
+ ti->error = "Unrecognised feature requested";
+ return -EINVAL;
+ }
- (*args_used)++;
+ argc--;
+ argv++;
+ (*args_used)++;
+ }
return 0;
}
@@ -1029,7 +1062,7 @@ static int parse_features(struct mirror_set *ms, unsigned argc, char **argv,
* log_type is "core" or "disk"
* #log_params is between 1 and 3
*
- * If present, features must be "handle_errors".
+ * If present, features must be "handle_errors" and/or "keep_log".
*/
static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
@@ -1394,8 +1427,11 @@ 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");
+
}
}
