dm: handle requests beyond end of device instead of using BUG_ON
authorMike Snitzer <snitzer@redhat.com>
Wed, 26 Sep 2012 22:45:42 +0000 (23:45 +0100)
committerAlasdair G Kergon <agk@redhat.com>
Wed, 26 Sep 2012 22:45:42 +0000 (23:45 +0100)
commitba1cbad93dd47223b1f3b8edd50dd9ef2abcb2ed
tree3cf301491e0c9ce60a8b90f8e9313ce95d75d695
parent7ba10aa6fbac7158a50bec142132b04bc480bb29
dm: handle requests beyond end of device instead of using BUG_ON

The access beyond the end of device BUG_ON that was introduced to
dm_request_fn via commit 29e4013de7ad950280e4b2208 ("dm: implement
REQ_FLUSH/FUA support for request-based dm") was an overly
drastic (but simple) response to this situation.

I have received a report that this BUG_ON was hit and now think
it would be better to use dm_kill_unmapped_request() to fail the clone
and original request with -EIO.

map_request() will assign the valid target returned by
dm_table_find_target to tio->ti.  But when the target
isn't valid tio->ti is never assigned (because map_request isn't
called); so add a check for tio->ti != NULL to dm_done().

Reported-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: stable@vger.kernel.org # v2.6.37+
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
drivers/md/dm.c