diff options
| -rw-r--r-- | drivers/md/dm-snap.c | 71 |
1 files changed, 64 insertions, 7 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index aec57d76db5d..944690bafd93 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -66,6 +66,18 @@ struct dm_snapshot { atomic_t pending_exceptions_count; + /* Protected by "lock" */ + sector_t exception_start_sequence; + + /* Protected by kcopyd single-threaded callback */ + sector_t exception_complete_sequence; + + /* + * A list of pending exceptions that completed out of order. + * Protected by kcopyd single-threaded callback. + */ + struct list_head out_of_order_list; + mempool_t *pending_pool; struct dm_exception_table pending; @@ -173,6 +185,14 @@ struct dm_snap_pending_exception { */ int started; + /* There was copying error. */ + int copy_error; + + /* A sequence number, it is used for in-order completion. */ + sector_t exception_sequence; + + struct list_head out_of_order_entry; + /* * For writing a complete chunk, bypassing the copy. */ @@ -1094,6 +1114,9 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) s->valid = 1; s->active = 0; atomic_set(&s->pending_exceptions_count, 0); + s->exception_start_sequence = 0; + s->exception_complete_sequence = 0; + INIT_LIST_HEAD(&s->out_of_order_list); init_rwsem(&s->lock); INIT_LIST_HEAD(&s->list); spin_lock_init(&s->pe_lock); @@ -1443,6 +1466,19 @@ static void commit_callback(void *context, int success) pending_complete(pe, success); } +static void complete_exception(struct dm_snap_pending_exception *pe) +{ + struct dm_snapshot *s = pe->snap; + + if (unlikely(pe->copy_error)) + pending_complete(pe, 0); + + else + /* Update the metadata if we are persistent */ + s->store->type->commit_exception(s->store, &pe->e, + commit_callback, pe); +} + /* * Called when the copy I/O has finished. kcopyd actually runs * this code so don't block. @@ -1452,13 +1488,32 @@ static void copy_callback(int read_err, unsigned long write_err, void *context) struct dm_snap_pending_exception *pe = context; struct dm_snapshot *s = pe->snap; - if (read_err || write_err) - pending_complete(pe, 0); + pe->copy_error = read_err || write_err; - else - /* Update the metadata if we are persistent */ - s->store->type->commit_exception(s->store, &pe->e, - commit_callback, pe); + if (pe->exception_sequence == s->exception_complete_sequence) { + s->exception_complete_sequence++; + complete_exception(pe); + + while (!list_empty(&s->out_of_order_list)) { + pe = list_entry(s->out_of_order_list.next, + struct dm_snap_pending_exception, out_of_order_entry); + if (pe->exception_sequence != s->exception_complete_sequence) + break; + s->exception_complete_sequence++; + list_del(&pe->out_of_order_entry); + complete_exception(pe); + } + } else { + struct list_head *lh; + struct dm_snap_pending_exception *pe2; + + list_for_each_prev(lh, &s->out_of_order_list) { + pe2 = list_entry(lh, struct dm_snap_pending_exception, out_of_order_entry); + if (pe2->exception_sequence < pe->exception_sequence) + break; + } + list_add(&pe->out_of_order_entry, lh); + } } /* @@ -1553,6 +1608,8 @@ __find_pending_exception(struct dm_snapshot *s, return NULL; } + pe->exception_sequence = s->exception_start_sequence++; + dm_insert_exception(&s->pending, &pe->e); return pe; @@ -2192,7 +2249,7 @@ static struct target_type origin_target = { static struct target_type snapshot_target = { .name = "snapshot", - .version = {1, 11, 1}, + .version = {1, 12, 0}, .module = THIS_MODULE, .ctr = snapshot_ctr, .dtr = snapshot_dtr, |