From f26b4b3c8a0db1b215caeeb80868381bc324d449 Mon Sep 17 00:00:00 2001 From: Richard Yao Date: Wed, 17 Feb 2016 16:16:25 -0500 Subject: [PATCH] txg visibility code should not execute under tc_open_lock The memory allocation and locking in `spa_txg_history_*()` can potentially block txg_hold_open for arbitrarily long periods of time. Signed-off-by: Richard Yao Signed-off-by: Brian Behlendorf Issue #4333 --- module/zfs/txg.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/module/zfs/txg.c b/module/zfs/txg.c index ed8007e05..9dda58c28 100644 --- a/module/zfs/txg.c +++ b/module/zfs/txg.c @@ -365,6 +365,7 @@ static void txg_quiesce(dsl_pool_t *dp, uint64_t txg) { tx_state_t *tx = &dp->dp_tx; + uint64_t tx_open_time; int g = txg & TXG_MASK; int c; @@ -376,10 +377,7 @@ txg_quiesce(dsl_pool_t *dp, uint64_t txg) ASSERT(txg == tx->tx_open_txg); tx->tx_open_txg++; - tx->tx_open_time = gethrtime(); - - spa_txg_history_set(dp->dp_spa, txg, TXG_STATE_OPEN, tx->tx_open_time); - spa_txg_history_add(dp->dp_spa, tx->tx_open_txg, tx->tx_open_time); + tx->tx_open_time = tx_open_time = gethrtime(); DTRACE_PROBE2(txg__quiescing, dsl_pool_t *, dp, uint64_t, txg); DTRACE_PROBE2(txg__opened, dsl_pool_t *, dp, uint64_t, tx->tx_open_txg); @@ -391,6 +389,9 @@ txg_quiesce(dsl_pool_t *dp, uint64_t txg) for (c = 0; c < max_ncpus; c++) mutex_exit(&tx->tx_cpu[c].tc_open_lock); + spa_txg_history_set(dp->dp_spa, txg, TXG_STATE_OPEN, tx_open_time); + spa_txg_history_add(dp->dp_spa, txg + 1, tx_open_time); + /* * Quiesce the transaction group by waiting for everyone to txg_exit(). */ -- 2.40.0