From 16db03cf3be6ecec973bcd90fdab14d18502495a Mon Sep 17 00:00:00 2001 From: Richard Yao Date: Wed, 17 Feb 2016 16:16:25 -0500 Subject: [PATCH] ZFSOnLinux 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 --- 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 71f9ddeeb056..dd886e3d7270 100644 --- a/module/zfs/txg.c +++ b/module/zfs/txg.c @@ -363,6 +363,7 @@ txg_quiesce(dsl_pool_t *dp, uint64_t txg) tx_state_t *tx = &dp->dp_tx; int g = txg & TXG_MASK; int c; + uint64_t tx_open_time; /* * Grab all tc_open_locks so nobody else can get into this txg. @@ -372,10 +373,7 @@ 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); @@ -387,6 +385,9 @@ 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(). */