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NEX-20218 Backport Illumos #9474 txg_kick() fails to see that we are quiescing, forcing transactions to their next stages without leaving them accumulate changes
MFV illumos-gate@fa41d87de9ec9000964c605eb01d6dc19e4a1abe
9464 txg_kick() fails to see that we are quiescing, forcing transactions to their next stages without leaving them accumulate changes
Reviewed by: Matt Ahrens <matt@delphix.com>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed by: Andriy Gapon <avg@FreeBSD.org>
Approved by: Dan McDonald <danmcd@joyent.com>
NEX-6859 TX-commit callback that is registered in sync-ctx causes system panic
Reviewed by: Sanjay Nadkarni <sanjay.nadkarni@nexenta.com>
Reviewed by: Saso Kiselkov <saso.kiselkov@nexenta.com>
@@ -20,10 +20,11 @@
*/
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Portions Copyright 2011 Martin Matuska
* Copyright (c) 2012, 2017 by Delphix. All rights reserved.
+ * Copyright 2016 Nexenta Systems, Inc. All rights reserved.
*/
#include <sys/zfs_context.h>
#include <sys/txg_impl.h>
#include <sys/dmu_impl.h>
@@ -102,10 +103,19 @@
* syncing state in order to reduce the latency of the administrative
* activity. To complete the syncing state, ZFS writes out a new uberblock,
* the root of the tree of blocks that comprise all state stored on the ZFS
* pool. Finally, if there is a quiesced txg waiting, we signal that it can
* now transition to the syncing state.
+ *
+ * It is possible to register a callback for a TX, so the callback will be
+ * called after sync of the corresponding TX-group to disk.
+ * Required callback and its optional argument can registered by using
+ * dmu_tx_callback_register().
+ * All callback are executed async via taskq (see txg_dispatch_callbacks).
+ * There are 2 possible cases when a registered callback is called:
+ * 1) the corresponding TX is commited to disk (the first arg is 0)
+ * 2) the corresponding TX is aborted (the first arg is ECANCELED)
*/
static void txg_sync_thread(void *arg);
static void txg_quiesce_thread(void *arg);
@@ -327,11 +337,27 @@
mutex_enter(&tc->tc_lock);
list_move_tail(&tc->tc_callbacks[g], tx_callbacks);
mutex_exit(&tc->tc_lock);
}
+/* This register function can be called only from sync-context */
void
+txg_register_callbacks_sync(dsl_pool_t *dp, uint64_t txg, list_t *tx_callbacks)
+{
+ tx_state_t *tx = &dp->dp_tx;
+ tx_cpu_t *tc = &tx->tx_cpu[CPU_SEQID];
+ txg_handle_t th;
+
+ VERIFY3U(tx->tx_syncing_txg, ==, txg);
+
+ th.th_cpu = tc;
+ th.th_txg = txg;
+
+ txg_register_callbacks(&th, tx_callbacks);
+}
+
+void
txg_rele_to_sync(txg_handle_t *th)
{
tx_cpu_t *tc = th->th_cpu;
int g = th->th_txg & TXG_MASK;
@@ -442,10 +468,34 @@
(void) taskq_dispatch(tx->tx_commit_cb_taskq, (task_func_t *)
txg_do_callbacks, cb_list, TQ_SLEEP);
}
}
+static boolean_t
+txg_is_syncing(dsl_pool_t *dp)
+{
+ tx_state_t *tx = &dp->dp_tx;
+ ASSERT(MUTEX_HELD(&tx->tx_sync_lock));
+ return (tx->tx_syncing_txg != 0);
+}
+
+static boolean_t
+txg_is_quiescing(dsl_pool_t *dp)
+{
+ tx_state_t *tx = &dp->dp_tx;
+ ASSERT(MUTEX_HELD(&tx->tx_sync_lock));
+ return (tx->tx_quiescing_txg != 0);
+}
+
+static boolean_t
+txg_has_quiesced_to_sync(dsl_pool_t *dp)
+{
+ tx_state_t *tx = &dp->dp_tx;
+ ASSERT(MUTEX_HELD(&tx->tx_sync_lock));
+ return (tx->tx_quiesced_txg != 0);
+}
+
static void
txg_sync_thread(void *arg)
{
dsl_pool_t *dp = arg;
spa_t *spa = dp->dp_spa;
@@ -468,11 +518,11 @@
*/
timer = (delta >= timeout ? 0 : timeout - delta);
while (!dsl_scan_active(dp->dp_scan) &&
!tx->tx_exiting && timer > 0 &&
tx->tx_synced_txg >= tx->tx_sync_txg_waiting &&
- tx->tx_quiesced_txg == 0 &&
+ !txg_has_quiesced_to_sync(dp) &&
dp->dp_dirty_total < zfs_dirty_data_sync) {
dprintf("waiting; tx_synced=%llu waiting=%llu dp=%p\n",
tx->tx_synced_txg, tx->tx_sync_txg_waiting, dp);
txg_thread_wait(tx, &cpr, &tx->tx_sync_more_cv, timer);
delta = ddi_get_lbolt() - start;
@@ -481,11 +531,11 @@
/*
* Wait until the quiesce thread hands off a txg to us,
* prompting it to do so if necessary.
*/
- while (!tx->tx_exiting && tx->tx_quiesced_txg == 0) {
+ while (!tx->tx_exiting && !txg_has_quiesced_to_sync(dp)) {
if (tx->tx_quiesce_txg_waiting < tx->tx_open_txg+1)
tx->tx_quiesce_txg_waiting = tx->tx_open_txg+1;
cv_broadcast(&tx->tx_quiesce_more_cv);
txg_thread_wait(tx, &cpr, &tx->tx_quiesce_done_cv, 0);
}
@@ -496,10 +546,11 @@
/*
* Consume the quiesced txg which has been handed off to
* us. This may cause the quiescing thread to now be
* able to quiesce another txg, so we must signal it.
*/
+ ASSERT(tx->tx_quiesced_txg != 0);
txg = tx->tx_quiesced_txg;
tx->tx_quiesced_txg = 0;
tx->tx_syncing_txg = txg;
DTRACE_PROBE2(txg__syncing, dsl_pool_t *, dp, uint64_t, txg);
cv_broadcast(&tx->tx_quiesce_more_cv);
@@ -544,28 +595,31 @@
* the "quiesced, waiting to sync" txg has been consumed
* by the sync thread.
*/
while (!tx->tx_exiting &&
(tx->tx_open_txg >= tx->tx_quiesce_txg_waiting ||
- tx->tx_quiesced_txg != 0))
+ txg_has_quiesced_to_sync(dp)))
txg_thread_wait(tx, &cpr, &tx->tx_quiesce_more_cv, 0);
if (tx->tx_exiting)
txg_thread_exit(tx, &cpr, &tx->tx_quiesce_thread);
txg = tx->tx_open_txg;
dprintf("txg=%llu quiesce_txg=%llu sync_txg=%llu\n",
txg, tx->tx_quiesce_txg_waiting,
tx->tx_sync_txg_waiting);
+ tx->tx_quiescing_txg = txg;
+
mutex_exit(&tx->tx_sync_lock);
txg_quiesce(dp, txg);
mutex_enter(&tx->tx_sync_lock);
/*
* Hand this txg off to the sync thread.
*/
dprintf("quiesce done, handing off txg %llu\n", txg);
+ tx->tx_quiescing_txg = 0;
tx->tx_quiesced_txg = txg;
DTRACE_PROBE2(txg__quiesced, dsl_pool_t *, dp, uint64_t, txg);
cv_broadcast(&tx->tx_sync_more_cv);
cv_broadcast(&tx->tx_quiesce_done_cv);
}
@@ -659,11 +713,12 @@
tx_state_t *tx = &dp->dp_tx;
ASSERT(!dsl_pool_config_held(dp));
mutex_enter(&tx->tx_sync_lock);
- if (tx->tx_syncing_txg == 0 &&
+ if (!txg_is_syncing(dp) &&
+ !txg_is_quiescing(dp) &&
tx->tx_quiesce_txg_waiting <= tx->tx_open_txg &&
tx->tx_sync_txg_waiting <= tx->tx_synced_txg &&
tx->tx_quiesced_txg <= tx->tx_synced_txg) {
tx->tx_quiesce_txg_waiting = tx->tx_open_txg + 1;
cv_broadcast(&tx->tx_quiesce_more_cv);
@@ -820,12 +875,10 @@
void *p = NULL;
txg_verify(tl->tl_spa, txg);
mutex_enter(&tl->tl_lock);
if ((tn = tl->tl_head[t]) != NULL) {
- ASSERT(tn->tn_member[t]);
- ASSERT(tn->tn_next[t] == NULL || tn->tn_next[t]->tn_member[t]);
p = (char *)tn - tl->tl_offset;
tl->tl_head[t] = tn->tn_next[t];
tn->tn_next[t] = NULL;
tn->tn_member[t] = 0;
}