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dm raid1: keep issuing IO after leg failure 

Currently if there is a leg failure, the bio will be put into the hold
list until userspace does a remove/replace on the leg.  Doing so in a
cluster config (clvmd) is problematic because there may be a temporary
path failure that results in cluster raid1 remove/replace.  Such
recovery takes a long time due to a full resync.

Update dm-raid1 to optionally ignore these failures so bios continue
being issued without interrupton.  To enable this feature userspace
must pass "keep_log" when creating the dm-raid1 device.

Signed-off-by: Lidong Zhong <lzhong@suse.com>
Tested-by: Liuhua Wang <lwang@suse.com>
Acked-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Lidong Zhong 2015-05-13 14:04:10 +08:00 committed by Mike Snitzer
parent f4ad317aed
commit ed63287dd6
1 changed files with 58 additions and 17 deletions
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75
drivers/md/dm-raid1.c
View File

@ -23,8 +23,10 @@
#define MAX_RECOVERY 1 /* Maximum number of regions recovered in parallel. */
#define DM_RAID1_HANDLE_ERRORS 0x01
#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);
@ -803,15 +817,21 @@ static void do_failures(struct mirror_set *ms, struct bio_list *failures)
/*
* If all the legs are dead, fail the I/O.
* If we have been told to handle errors, hold the bio
* and wait for userspace to deal with the problem.
* If the device has failed and keep_log is enabled,
* fail the I/O.
*
* If we have been told to handle errors, and keep_log
* isn't enabled, hold the bio and wait for userspace to
* deal with the problem.
*
* Otherwise pretend that the I/O succeeded. (This would
* be wrong if the failed leg returned after reboot and
* got replicated back to the good legs.)
*/
if (!get_valid_mirror(ms))
if (unlikely(!get_valid_mirror(ms) || (keep_log(ms) && ms->log_failure)))
bio_endio(bio, -EIO);
else if (errors_handled(ms))
else if (errors_handled(ms) && !keep_log(ms))
hold_bio(ms, bio);
else
bio_endio(bio, 0);
@ -987,6 +1007,7 @@ 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;
@ -1007,15 +1028,25 @@ 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";
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;
}
argc--;
argv++;
(*args_used)++;
}
if (!errors_handled(ms) && keep_log(ms)) {
ti->error = "keep_log feature requires the handle_errors feature";
return -EINVAL;
}
(*args_used)++;
return 0;
}
@ -1029,7 +1060,7 @@ 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, supported features are "handle_errors" and "keep_log".
*/
static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
@ -1363,6 +1394,7 @@ static void mirror_status(struct dm_target *ti, status_type_t type,
unsigned status_flags, char *result, unsigned maxlen)
{
unsigned int m, sz = 0;
int num_feature_args = 0;
struct mirror_set *ms = (struct mirror_set *) ti->private;
struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
char buffer[ms->nr_mirrors + 1];
@ -1392,8 +1424,17 @@ 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)
DMEMIT(" 1 handle_errors");
num_feature_args += !!errors_handled(ms);
num_feature_args += !!keep_log(ms);
if (num_feature_args) {
DMEMIT(" %d", num_feature_args);
if (errors_handled(ms))
DMEMIT(" handle_errors");
if (keep_log(ms))
DMEMIT(" keep_log");
}
break;
}
}
@ -1413,7 +1454,7 @@ static int mirror_iterate_devices(struct dm_target *ti,
static struct target_type mirror_target = {
.name = "mirror",
.version = {1, 13, 2},
.version = {1, 14, 0},
.module = THIS_MODULE,
.ctr = mirror_ctr,
.dtr = mirror_dtr,