svn commit: r314273 - in head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs: . sys
Andriy Gapon
avg at FreeBSD.org
Sat Feb 25 16:45:54 UTC 2017
Author: avg
Date: Sat Feb 25 16:45:53 2017
New Revision: 314273
URL: https://svnweb.freebsd.org/changeset/base/314273
Log:
zfs: call spa_deadman on a taskqueue thread
callout(9) prohibits callout functions from sleeping.
illumos mutexes are emulated using sx(9).
spa_deadman() calls vdev_deadman() and the latter acquires vq_lock.
As a result we can get a more confusing panic instead of a specific
panic or no panic:
sleepq_add: td 0xfffff80019669960 to sleep on wchan 0xfffff8001cff4d88 with sleeping prohibited
This change adds another level of indirection where the deadman
callout schedules spa_deadman() to be executed on taskqueue_thread.
While there, use callout_schedule(0 instead of callout_reset()
in spa_sync().
Discussed with: mav
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D9762
Modified:
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_misc.c
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c Sat Feb 25 16:39:21 2017 (r314272)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c Sat Feb 25 16:45:53 2017 (r314273)
@@ -174,10 +174,6 @@ uint_t zio_taskq_basedc = 80; /* base
boolean_t spa_create_process = B_TRUE; /* no process ==> no sysdc */
extern int zfs_sync_pass_deferred_free;
-#ifndef illumos
-extern void spa_deadman(void *arg);
-#endif
-
/*
* This (illegal) pool name is used when temporarily importing a spa_t in order
* to get the vdev stats associated with the imported devices.
@@ -6883,8 +6879,8 @@ spa_sync(spa_t *spa, uint64_t txg)
spa->spa_sync_starttime + spa->spa_deadman_synctime));
#else /* !illumos */
#ifdef _KERNEL
- callout_reset(&spa->spa_deadman_cycid,
- hz * spa->spa_deadman_synctime / NANOSEC, spa_deadman, spa);
+ callout_schedule(&spa->spa_deadman_cycid,
+ hz * spa->spa_deadman_synctime / NANOSEC);
#endif
#endif /* illumos */
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_misc.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_misc.c Sat Feb 25 16:39:21 2017 (r314272)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_misc.c Sat Feb 25 16:45:53 2017 (r314273)
@@ -597,8 +597,8 @@ spa_lookup(const char *name)
* If the zfs_deadman_enabled flag is set then it inspects all vdev queues
* looking for potentially hung I/Os.
*/
-void
-spa_deadman(void *arg)
+static void
+spa_deadman(void *arg, int pending)
{
spa_t *spa = arg;
@@ -627,6 +627,16 @@ spa_deadman(void *arg)
#endif
}
+#if defined(__FreeBSD__) && defined(_KERNEL)
+static void
+spa_deadman_timeout(void *arg)
+{
+ spa_t *spa = arg;
+
+ taskqueue_enqueue(taskqueue_thread, &spa->spa_deadman_task);
+}
+#endif
+
/*
* Create an uninitialized spa_t with the given name. Requires
* spa_namespace_lock. The caller must ensure that the spa_t doesn't already
@@ -698,7 +708,23 @@ spa_add(const char *name, nvlist_t *conf
mutex_exit(&cpu_lock);
#else /* !illumos */
#ifdef _KERNEL
+ /*
+ * callout(9) does not provide a way to initialize a callout with
+ * a function and an argument, so we use callout_reset() to schedule
+ * the callout in the very distant future. Even if that event ever
+ * fires, it should be okayas we won't have any active zio-s.
+ * But normally spa_sync() will reschedule the callout with a proper
+ * timeout.
+ * callout(9) does not allow the callback function to sleep but
+ * vdev_deadman() needs to acquire vq_lock and illumos mutexes are
+ * emulated using sx(9). For this reason spa_deadman_timeout()
+ * will schedule spa_deadman() as task on a taskqueue that allows
+ * sleeping.
+ */
+ TASK_INIT(&spa->spa_deadman_task, 0, spa_deadman, spa);
callout_init(&spa->spa_deadman_cycid, 1);
+ callout_reset_sbt(&spa->spa_deadman_cycid, SBT_MAX, 0,
+ spa_deadman_timeout, spa, 0);
#endif
#endif
refcount_create(&spa->spa_refcount);
@@ -811,6 +837,7 @@ spa_remove(spa_t *spa)
#else /* !illumos */
#ifdef _KERNEL
callout_drain(&spa->spa_deadman_cycid);
+ taskqueue_drain(taskqueue_thread, &spa->spa_deadman_task);
#endif
#endif
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h Sat Feb 25 16:39:21 2017 (r314272)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h Sat Feb 25 16:45:53 2017 (r314273)
@@ -267,6 +267,7 @@ struct spa {
#else /* !illumos */
#ifdef _KERNEL
struct callout spa_deadman_cycid; /* callout id */
+ struct task spa_deadman_task;
#endif
#endif /* illumos */
uint64_t spa_deadman_calls; /* number of deadman calls */
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