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authorJun'ichi Nomura <j-nomura@ce.jp.nec.com>2012-03-28 21:41:25 +0400
committerAlasdair G Kergon <agk@redhat.com>2012-03-28 21:41:25 +0400
commit466891f9959b500e037836737c064a72f2bbe8cf (patch)
treed50448abe03d595fb5f00671ff7aec9a35e3cdb0 /drivers
parent4d7b38b7d944a79da3793b6c92d38682f3905ac9 (diff)
downloadlinux-466891f9959b500e037836737c064a72f2bbe8cf.tar.xz
dm mpath: detect invalid map_context
The map_context pointer should always be set. However, we have reports that upon requeuing it is not set correctly. So add set and clear functions with a BUG_ON() to track the issue properly. Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: Mike Snitzer <snitzer@redhat.com> Acked-by: Hannes Reinecke <hare@suse.de> Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: Dave Wysochanski <dwysocha@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/md/dm-mpath.c46
1 files changed, 32 insertions, 14 deletions
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 801d92d237cf..e92a0005eeff 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -226,6 +226,27 @@ static void free_multipath(struct multipath *m)
kfree(m);
}
+static int set_mapinfo(struct multipath *m, union map_info *info)
+{
+ struct dm_mpath_io *mpio;
+
+ mpio = mempool_alloc(m->mpio_pool, GFP_ATOMIC);
+ if (!mpio)
+ return -ENOMEM;
+
+ memset(mpio, 0, sizeof(*mpio));
+ info->ptr = mpio;
+
+ return 0;
+}
+
+static void clear_mapinfo(struct multipath *m, union map_info *info)
+{
+ struct dm_mpath_io *mpio = info->ptr;
+
+ info->ptr = NULL;
+ mempool_free(mpio, m->mpio_pool);
+}
/*-----------------------------------------------
* Path selection
@@ -341,13 +362,14 @@ static int __must_push_back(struct multipath *m)
}
static int map_io(struct multipath *m, struct request *clone,
- struct dm_mpath_io *mpio, unsigned was_queued)
+ union map_info *map_context, unsigned was_queued)
{
int r = DM_MAPIO_REMAPPED;
size_t nr_bytes = blk_rq_bytes(clone);
unsigned long flags;
struct pgpath *pgpath;
struct block_device *bdev;
+ struct dm_mpath_io *mpio = map_context->ptr;
spin_lock_irqsave(&m->lock, flags);
@@ -423,7 +445,6 @@ static void dispatch_queued_ios(struct multipath *m)
{
int r;
unsigned long flags;
- struct dm_mpath_io *mpio;
union map_info *info;
struct request *clone, *n;
LIST_HEAD(cl);
@@ -436,16 +457,15 @@ static void dispatch_queued_ios(struct multipath *m)
list_del_init(&clone->queuelist);
info = dm_get_rq_mapinfo(clone);
- mpio = info->ptr;
- r = map_io(m, clone, mpio, 1);
+ r = map_io(m, clone, info, 1);
if (r < 0) {
- mempool_free(mpio, m->mpio_pool);
+ clear_mapinfo(m, info);
dm_kill_unmapped_request(clone, r);
} else if (r == DM_MAPIO_REMAPPED)
dm_dispatch_request(clone);
else if (r == DM_MAPIO_REQUEUE) {
- mempool_free(mpio, m->mpio_pool);
+ clear_mapinfo(m, info);
dm_requeue_unmapped_request(clone);
}
}
@@ -908,20 +928,16 @@ static int multipath_map(struct dm_target *ti, struct request *clone,
union map_info *map_context)
{
int r;
- struct dm_mpath_io *mpio;
struct multipath *m = (struct multipath *) ti->private;
- mpio = mempool_alloc(m->mpio_pool, GFP_ATOMIC);
- if (!mpio)
+ if (set_mapinfo(m, map_context) < 0)
/* ENOMEM, requeue */
return DM_MAPIO_REQUEUE;
- memset(mpio, 0, sizeof(*mpio));
- map_context->ptr = mpio;
clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;
- r = map_io(m, clone, mpio, 0);
+ r = map_io(m, clone, map_context, 0);
if (r < 0 || r == DM_MAPIO_REQUEUE)
- mempool_free(mpio, m->mpio_pool);
+ clear_mapinfo(m, map_context);
return r;
}
@@ -1261,13 +1277,15 @@ static int multipath_end_io(struct dm_target *ti, struct request *clone,
struct path_selector *ps;
int r;
+ BUG_ON(!mpio);
+
r = do_end_io(m, clone, error, mpio);
if (pgpath) {
ps = &pgpath->pg->ps;
if (ps->type->end_io)
ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes);
}
- mempool_free(mpio, m->mpio_pool);
+ clear_mapinfo(m, map_context);
return r;
}