From 513168abd267f84ebcb688b4e1d42a2abd4fedce Mon Sep 17 00:00:00 2001 From: ab-oe Date: Fri, 26 Feb 2016 08:33:44 +0100 Subject: [PATCH] Make zvol update volsize operation synchronous. There is a race condition when new transaction group is added to dp->dp_dirty_datasets list by the zap_update in the zvol_update_volsize. Meanwhile, before these dirty data are synchronized, the receive process can cause that dmu_recv_end_sync is executed. Then finally dirty data are going to be synchronized but the synchronization ends with the NULL pointer dereference error. Signed-off-by: ab-oe Signed-off-by: Brian Behlendorf Closes #4116 --- module/zfs/zvol.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/module/zfs/zvol.c b/module/zfs/zvol.c index c90e4ec6b9..034cf6a6a9 100644 --- a/module/zfs/zvol.c +++ b/module/zfs/zvol.c @@ -276,6 +276,7 @@ zvol_update_volsize(uint64_t volsize, objset_t *os) { dmu_tx_t *tx; int error; + uint64_t txg; ASSERT(MUTEX_HELD(&zvol_state_lock)); @@ -287,11 +288,14 @@ zvol_update_volsize(uint64_t volsize, objset_t *os) dmu_tx_abort(tx); return (SET_ERROR(error)); } + txg = dmu_tx_get_txg(tx); error = zap_update(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize, tx); dmu_tx_commit(tx); + txg_wait_synced(dmu_objset_pool(os), txg); + if (error == 0) error = dmu_free_long_range(os, ZVOL_OBJ, volsize, DMU_OBJECT_END);