On Thu, Feb 26 2015 at 11:40am -0500, Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote: > In the function snapshot_resume we perform exception store handover. If > there is another active snapshot target, the exception store is moved from > this target to the target that is being resume. > > The problem is that if there is some pending exception, it will point to > an incorrect exception store after that handover, causing crash in BUG in > dm-snap-persistent.c:get_exception - see bug 1177389. > > This bug can be triggered by repeatedly changing snapshot permissions with > "lvchange -p r" and "lvchange -p rw" while there are writes on the > associated origin device. > > To fix this bug, we must suspend the origin device when doing the > exception store handover to make sure that there is no pending exception. > > This patch: > - introdices _origin_hash that keeps track of dm_origin structures. > - introduces function __lookup_dm_origin, __insert_dm_origin and > __remove_dm_origin that manipulate the origin hash. > - modifies snapshot_resume so that it calls dm_internal_suspend_fast and > dm_internal_resume_fast on the origin device. > > Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx> I staged this for 4.0 here (note I bumped the target versions and revised the header slightly): https://git.kernel.org/cgit/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-for-4.0&id=b735fede8d957d9d255e9c5cf3964cfa59799637 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
