diff options
author | Jonathan Brassow <jbrassow@redhat.com> | 2007-07-12 17:29:04 +0100 |
---|---|---|
committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-12 15:01:08 -0700 |
commit | f44db678edcc6f4c2779ac43f63f0b9dfa28b724 (patch) | |
tree | bbd835d00ca6ed0805c5c7331ebc5dd7978d299c | |
parent | d0d444c7d48c14d59f665887c758fde248f1cb37 (diff) | |
download | linux-f44db678edcc6f4c2779ac43f63f0b9dfa28b724.tar.bz2 |
dm raid1: handle resync failures
Device-mapper mirroring currently takes a best effort approach to
recovery - failures during mirror synchronization are completely ignored.
This means that regions are marked 'in-sync' and 'clean' and removed
from the hash list. Future reads and writes that query the region
will incorrectly interpret the region as in-sync.
This patch handles failures during the recovery process. If a failure
occurs, the region is marked as 'not-in-sync' (aka RH_NOSYNC) and added
to a new list 'failed_recovered_regions'.
Regions on the 'failed_recovered_regions' list are not marked as 'clean'
upon removal from the list. Furthermore, if the DM_RAID1_HANDLE_ERRORS
flag is set, the region is marked as 'not-in-sync'. This action prevents
any future read-balancing from choosing an invalid device because of the
'not-in-sync' status.
If "handle_errors" is not specified when creating a mirror (leaving the
DM_RAID1_HANDLE_ERRORS flag unset), failures will be ignored exactly as they
would be without this patch. This is to preserve backwards compatibility with
user-space tools, such as 'pvmove'. However, since future read-balancing
policies will rely on the correct sync status of a region, a user must choose
"handle_errors" when using read-balancing.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | drivers/md/dm-raid1.c | 44 |
1 files changed, 41 insertions, 3 deletions
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c index 04dce7a66494..dee4221caa73 100644 --- a/drivers/md/dm-raid1.c +++ b/drivers/md/dm-raid1.c @@ -24,6 +24,7 @@ #define DM_IO_PAGES 64 #define DM_RAID1_HANDLE_ERRORS 0x01 +#define errors_handled(p) ((p)->features & DM_RAID1_HANDLE_ERRORS) static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped); @@ -85,6 +86,7 @@ struct region_hash { struct list_head clean_regions; struct list_head quiesced_regions; struct list_head recovered_regions; + struct list_head failed_recovered_regions; }; enum { @@ -204,6 +206,7 @@ static int rh_init(struct region_hash *rh, struct mirror_set *ms, INIT_LIST_HEAD(&rh->clean_regions); INIT_LIST_HEAD(&rh->quiesced_regions); INIT_LIST_HEAD(&rh->recovered_regions); + INIT_LIST_HEAD(&rh->failed_recovered_regions); rh->region_pool = mempool_create_kmalloc_pool(MIN_REGIONS, sizeof(struct region)); @@ -368,6 +371,7 @@ static void rh_update_states(struct region_hash *rh) LIST_HEAD(clean); LIST_HEAD(recovered); + LIST_HEAD(failed_recovered); /* * Quickly grab the lists. @@ -389,6 +393,15 @@ static void rh_update_states(struct region_hash *rh) list_for_each_entry (reg, &recovered, list) list_del(®->hash_list); } + + if (!list_empty(&rh->failed_recovered_regions)) { + list_splice(&rh->failed_recovered_regions, &failed_recovered); + INIT_LIST_HEAD(&rh->failed_recovered_regions); + + list_for_each_entry(reg, &failed_recovered, list) + list_del(®->hash_list); + } + spin_unlock(&rh->region_lock); write_unlock_irq(&rh->hash_lock); @@ -403,6 +416,11 @@ static void rh_update_states(struct region_hash *rh) mempool_free(reg, rh->region_pool); } + list_for_each_entry_safe(reg, next, &failed_recovered, list) { + complete_resync_work(reg, errors_handled(rh->ms) ? 0 : 1); + mempool_free(reg, rh->region_pool); + } + list_for_each_entry_safe(reg, next, &clean, list) { rh->log->type->clear_region(rh->log, reg->key); mempool_free(reg, rh->region_pool); @@ -555,13 +573,17 @@ static struct region *rh_recovery_start(struct region_hash *rh) return reg; } -/* FIXME: success ignored for now */ static void rh_recovery_end(struct region *reg, int success) { struct region_hash *rh = reg->rh; spin_lock_irq(&rh->region_lock); - list_add(®->list, ®->rh->recovered_regions); + if (success) + list_add(®->list, ®->rh->recovered_regions); + else { + reg->state = RH_NOSYNC; + list_add(®->list, ®->rh->failed_recovered_regions); + } spin_unlock_irq(&rh->region_lock); wake(rh->ms); @@ -633,7 +655,14 @@ static void recovery_complete(int read_err, unsigned int write_err, { struct region *reg = (struct region *) context; - /* FIXME: better error handling */ + if (read_err) + /* Read error means the failure of default mirror. */ + DMERR_LIMIT("Unable to read primary mirror during recovery"); + + if (write_err) + DMERR_LIMIT("Write error during recovery (error = 0x%x)", + write_err); + rh_recovery_end(reg, !(read_err || write_err)); } @@ -1145,6 +1174,15 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv) argv += args_used; argc -= args_used; + /* + * Any read-balancing addition depends on the + * DM_RAID1_HANDLE_ERRORS flag being present. + * This is because the decision to balance depends + * on the sync state of a region. If the above + * flag is not present, we ignore errors; and + * the sync state may be inaccurate. + */ + if (argc) { ti->error = "Too many mirror arguments"; free_context(ms, ti, ms->nr_mirrors); |