dmu_tx: Fix possible NULL pointer dereference

[zfs.git] / module / zfs / dmu_tx.c

diff --git a/module/zfs/dmu_tx.c b/module/zfs/dmu_tx.c
index 31c88c9..fd71413 100644 (file)
--- a/module/zfs/dmu_tx.c
+++ b/module/zfs/dmu_tx.c
@@ -773,12 +773,13 @@ void
 dmu_tx_hold_space(dmu_tx_t *tx, uint64_t space)
 {
        dmu_tx_hold_t *txh;
+
        ASSERT(tx->tx_txg == 0);
 
        txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
            DMU_NEW_OBJECT, THT_SPACE, space, 0);
-
-       txh->txh_space_towrite += space;
+       if (txh)
+               txh->txh_space_towrite += space;
 }
 
 int
@@ -1089,12 +1090,15 @@ dmu_tx_unassign(dmu_tx_t *tx)
 int
 dmu_tx_assign(dmu_tx_t *tx, uint64_t txg_how)
 {
+       hrtime_t before, after;
        int err;
 
        ASSERT(tx->tx_txg == 0);
        ASSERT(txg_how != 0);
        ASSERT(!dsl_pool_sync_context(tx->tx_pool));
 
+       before = gethrtime();
+
        while ((err = dmu_tx_try_assign(tx, txg_how)) != 0) {
                dmu_tx_unassign(tx);
 
@@ -1106,6 +1110,11 @@ dmu_tx_assign(dmu_tx_t *tx, uint64_t txg_how)
 
        txg_rele_to_quiesce(&tx->tx_txgh);
 
+       after = gethrtime();
+
+       dsl_pool_tx_assign_add_usecs(tx->tx_pool,
+           (after - before) / NSEC_PER_USEC);
+
        return (0);
 }
 
@@ -1312,6 +1321,8 @@ dmu_tx_hold_spill(dmu_tx_t *tx, uint64_t object)
 
        txh = dmu_tx_hold_object_impl(tx, tx->tx_objset, object,
            THT_SPILL, 0, 0);
+       if (txh == NULL)
+               return;
 
        dn = txh->txh_dnode;