Allow the snapshot target to be able to verify its state relative to a
requested operation. Allows for invalid operations to be prevented,
e.g. an attempt handover an "old" snapshot's exceptions without it
having been suspended first.
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
drivers/md/dm-snap.c | 17 ++++++++++++++++-
1 files changed, 16 insertions(+), 1 deletions(-)
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 6181878..be37439 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -72,6 +72,9 @@ struct dm_snapshot {
/* Origin writes don't trigger exceptions until this is set */
int active;
+ /* Set if the parent device is suspended */
+ int suspended;
+
mempool_t *pending_pool;
atomic_t pending_exceptions_count;
@@ -632,6 +635,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
s->ti = ti;
s->valid = 1;
s->active = 0;
+ s->suspended = 0;
atomic_set(&s->pending_exceptions_count, 0);
init_rwsem(&s->lock);
spin_lock_init(&s->pe_lock);
@@ -1138,12 +1142,22 @@ static int snapshot_end_io(struct dm_target *ti, struct bio *bio,
return 0;
}
+static void snapshot_presuspend(struct dm_target *ti)
+{
+ struct dm_snapshot *s = ti->private;
+
+ down_write(&s->lock);
+ s->suspended = 1;
+ up_write(&s->lock);
+}
+
static void snapshot_resume(struct dm_target *ti)
{
struct dm_snapshot *s = ti->private;
down_write(&s->lock);
s->active = 1;
+ s->suspended = 0;
up_write(&s->lock);
}
@@ -1434,12 +1448,13 @@ static struct target_type origin_target = {
static struct target_type snapshot_target = {
.name = "snapshot",
- .version = {1, 8, 0},
+ .version = {1, 9, 0},
.module = THIS_MODULE,
.ctr = snapshot_ctr,
.dtr = snapshot_dtr,
.map = snapshot_map,
.end_io = snapshot_end_io,
+ .presuspend = snapshot_presuspend,
.resume = snapshot_resume,
.status = snapshot_status,
.iterate_devices = snapshot_iterate_devices,
--
1.6.5.rc2
--
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