__switch_pg() sets m->current_pg before initializing the pathgroup. If
probe_active_paths() is called and pathgroup has not been fully
initialized, IO to the paths may fail, even though they will be usable
when the pathgroup has finished initializing. Instead, skip sending IO
in this situation and just return the number of usable paths. The next
request will wait for the pathgroup to be fully initialized.
Fixes: d5d16fabe431 ("dm mpath: Interface for explicit probing of active paths")
Signed-off-by: Benjamin Marzinski <bmarz...@redhat.com>
---
drivers/md/dm-mpath.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index af17a35c6457..53861ad5dd1d 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -2068,19 +2068,28 @@ static int probe_path(struct pgpath *pgpath)
*
* Return -ENOTCONN if no valid path is left (even outside of current_pg). We
* cannot probe paths in other pgs without switching current_pg, so if valid
- * paths are only in different pgs, they may or may not work. Userspace can
- * submit a request and we'll switch. If the request fails, it may need to
+ * paths are only in different pgs, they may or may not work. Additionally
+ * we should not probe paths in a pathgroup that is in the process of
+ * Initializing. Userspace can submit a request and we'll switch and wait
+ * for the pathgroup to be initialized. If the request fails, it may need to
* probe again.
*/
static int probe_active_paths(struct multipath *m)
{
struct pgpath *pgpath;
struct priority_group *pg;
+ unsigned long flags;
int r = 0;
mutex_lock(&m->work_mutex);
- pg = READ_ONCE(m->current_pg);
+ spin_lock_irqsave(&m->lock, flags);
+ if (test_bit(MPATHF_QUEUE_IO, &m->flags))
+ pg = NULL;
+ else
+ pg = m->current_pg;
+ spin_unlock_irqrestore(&m->lock, flags);
+
if (pg) {
list_for_each_entry(pgpath, &pg->pgpaths, list) {
if (!pgpath->is_active)
--
2.48.1
