From 138728dc96529f20dfe970c470e51885a60e329f Mon Sep 17 00:00:00 2001 From: Alasdair G Kergon Date: Mon, 27 Mar 2006 01:17:50 -0800 Subject: [PATCH] dm snapshot: fix kcopyd destructor Before removing a snapshot, wait for the completion of any kcopyd jobs using it. Do this by maintaining a count (nr_jobs) of how many outstanding jobs each kcopyd_client has. The snapshot destructor first unregisters the snapshot so that no new kcopyd jobs (created by writes to the origin) will reference that particular snapshot. kcopyd_client_destroy() is now run next to wait for the completion of any outstanding jobs before the snapshot exception structures (that those jobs reference) are freed. Signed-off-by: Alasdair G Kergon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/md/dm-snap.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'drivers/md/dm-snap.c') diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index a5765f9fbe0..08312b46463 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -559,8 +559,12 @@ static void snapshot_dtr(struct dm_target *ti) { struct dm_snapshot *s = (struct dm_snapshot *) ti->private; + /* Prevent further origin writes from using this snapshot. */ + /* After this returns there can be no new kcopyd jobs. */ unregister_snapshot(s); + kcopyd_client_destroy(s->kcopyd_client); + exit_exception_table(&s->pending, pending_cache); exit_exception_table(&s->complete, exception_cache); @@ -569,7 +573,7 @@ static void snapshot_dtr(struct dm_target *ti) dm_put_device(ti, s->origin); dm_put_device(ti, s->cow); - kcopyd_client_destroy(s->kcopyd_client); + kfree(s); } -- cgit v1.2.3