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-rw-r--r--drivers/md/dm-snap.c41
1 files changed, 19 insertions, 22 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 7401540086d..874f145431d 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -49,6 +49,11 @@ struct pending_exception {
struct bio_list snapshot_bios;
/*
+ * Short-term queue of pending exceptions prior to submission.
+ */
+ struct list_head list;
+
+ /*
* Other pending_exceptions that are processing this
* chunk. When this list is empty, we know we can
* complete the origins.
@@ -930,8 +935,9 @@ static int __origin_write(struct list_head *snapshots, struct bio *bio)
int r = 1, first = 1;
struct dm_snapshot *snap;
struct exception *e;
- struct pending_exception *pe, *last = NULL;
+ struct pending_exception *pe, *next_pe, *last = NULL;
chunk_t chunk;
+ LIST_HEAD(pe_queue);
/* Do all the snapshots on this origin */
list_for_each_entry (snap, snapshots, list) {
@@ -965,12 +971,19 @@ static int __origin_write(struct list_head *snapshots, struct bio *bio)
snap->valid = 0;
} else {
- if (last)
+ if (first) {
+ bio_list_add(&pe->origin_bios, bio);
+ r = 0;
+ first = 0;
+ }
+ if (last && list_empty(&pe->siblings))
list_merge(&pe->siblings,
&last->siblings);
-
+ if (!pe->started) {
+ pe->started = 1;
+ list_add_tail(&pe->list, &pe_queue);
+ }
last = pe;
- r = 0;
}
}
@@ -980,24 +993,8 @@ static int __origin_write(struct list_head *snapshots, struct bio *bio)
/*
* Now that we have a complete pe list we can start the copying.
*/
- if (last) {
- pe = last;
- do {
- down_write(&pe->snap->lock);
- if (first)
- bio_list_add(&pe->origin_bios, bio);
- if (!pe->started) {
- pe->started = 1;
- up_write(&pe->snap->lock);
- start_copy(pe);
- } else
- up_write(&pe->snap->lock);
- first = 0;
- pe = list_entry(pe->siblings.next,
- struct pending_exception, siblings);
-
- } while (pe != last);
- }
+ list_for_each_entry_safe(pe, next_pe, &pe_queue, list)
+ start_copy(pe);
return r;
}