dm snapshot: add new persistent store option to support overflow
authorMike Snitzer <snitzer@redhat.com>
Thu, 8 Oct 2015 22:05:41 +0000 (18:05 -0400)
committerMike Snitzer <snitzer@redhat.com>
Fri, 9 Oct 2015 20:57:03 +0000 (16:57 -0400)
commitb0d3cc011e532d8c9db76cf717bcafa53c135595
treed74330dcf71a599d637a7eecad8b56cdbd4487b9
parent2bffa1503c5c06192eb1459180fac4416575a966
dm snapshot: add new persistent store option to support overflow

Commit 76c44f6d80 introduced the possibly for "Overflow" to be reported
by the snapshot device's status.  Older userspace (e.g. lvm2) does not
handle the "Overflow" status response.

Fix this incompatibility by requiring newer userspace code, that can
cope with "Overflow", request the persistent store with overflow support
by using "PO" (Persistent with Overflow) for the snapshot store type.

Reported-by: Zdenek Kabelac <zkabelac@redhat.com>
Fixes: 76c44f6d80 ("dm snapshot: don't invalidate on-disk image on snapshot write overflow")
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Documentation/device-mapper/snapshot.txt
drivers/md/dm-exception-store.c
drivers/md/dm-exception-store.h
drivers/md/dm-snap-persistent.c
drivers/md/dm-snap-transient.c
drivers/md/dm-snap.c