[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 <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Alasdair G Kergon
2006-03-27 01:17:50 -08:00
committed by Linus Torvalds
parent 969429b504
commit 138728dc96
2 changed files with 21 additions and 2 deletions

View File

@ -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);
}