[25/99] dm snapshot: require non zero chunk size by end of ctr

From: Greg KH
Date: Fri Nov 06 2009 - 17:39:50 EST

2.6.31-stable review patch. If anyone has any objections, please let us know.

From: Mikulas Patocka <mpatocka@xxxxxxxxxx>

commit 3f2412dc85260e5aae7ebb03bf50d5b1407e3083 upstream.

If we are creating snapshot with memory-stored exception store, fail if
the user didn't specify chunk size. Zero chunk size would probably crash
a lot of places in the rest of snapshot code.

Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Reviewed-by: Jonathan Brassow <jbrassow@xxxxxxxxxx>
Reviewed-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Alasdair G Kergon <agk@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

drivers/md/dm-snap.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -673,6 +673,11 @@ static int snapshot_ctr(struct dm_target
INIT_WORK(&s->queued_bios_work, flush_queued_bios);

+ if (!s->store->chunk_size) {
+ ti->error = "Chunk size not set";
+ goto bad_load_and_register;
+ }
/* Add snapshot to the list of snapshots for this origin */
/* Exceptions aren't triggered till snapshot_resume() is called */
if (register_snapshot(s)) {

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