From: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Merging more than one snapshot is not supported.
__find_merging_snapshot() will find the merging snapshot for a given
origin device.
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
drivers/md/dm-snap.c | 36 +++++++++++++++++++++++++++++++++++-
1 files changed, 35 insertions(+), 1 deletions(-)
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index c232460..a0ac29f 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -331,9 +331,29 @@ out:
return count;
}
+static struct dm_snapshot *__find_merging_snapshot(struct block_device *origin)
+{
+ struct dm_snapshot *s, *merging_snap = NULL;
+ struct origin *o;
+
+ o = __lookup_origin(origin);
+ if (!o)
+ return NULL;
+
+ list_for_each_entry(s, &o->snapshots, list) {
+ if (is_merge(s->ti)) {
+ merging_snap = s;
+ break;
+ }
+ }
+
+ return merging_snap;
+}
+
static int __validate_exception_handover(struct dm_snapshot *snap)
{
struct dm_snapshot *snap_src = NULL, *snap_dest = NULL;
+ struct block_device *bdev = snap->origin->bdev;
int r = 0;
/* Does snapshot need exceptions handed over to it? */
@@ -345,8 +365,22 @@ static int __validate_exception_handover(struct dm_snapshot *snap)
goto out;
}
- if (snap_src)
+ if (snap_src) {
+ /* This snapshot is a handover destination */
+ if (!is_merge(snap->ti)) {
+ r = 1;
+ goto out;
+ }
+
+ /* Do not allow more than one merging snapshot */
+ if (__find_merging_snapshot(bdev)) {
+ snap->ti->error = "A snapshot is already merging.";
+ r = -EINVAL;
+ goto out;
+ }
+
r = 1;
+ }
out:
return r;
--
1.6.5.2
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