From 75a089ed34befb8d11df9be92a4438cc49554bf6 Mon Sep 17 00:00:00 2001 From: Brian Behlendorf Date: Wed, 24 Feb 2021 10:00:21 -0800 Subject: [PATCH 28/38] Fix overly broad locking in spa_vdev_config_exit() Calling vdev_free() only requires the we acquire the spa config SCL_STATE_ALL locks, not the SCL_ALL locks. In particular, we need need to avoid taking the SCL_CONFIG lock (included in SCL_ALL) as a writer since this can lead to a deadlock. The txg_sync_thread() may block in spa_txg_history_init_io() when taking the SCL_CONFIG lock as a reading when it detects there's a pending writer. Reviewed-by: Igor Kozhukhov Reviewed-by: Mark Maybee Signed-off-by: Brian Behlendorf Closes #11585 --- module/zfs/spa_misc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) Index: zfs/module/zfs/spa_misc.c =================================================================== --- zfs.orig/module/zfs/spa_misc.c +++ zfs/module/zfs/spa_misc.c @@ -1274,9 +1274,9 @@ spa_vdev_config_exit(spa_t *spa, vdev_t */ vdev_autotrim_stop_wait(vd); - spa_config_enter(spa, SCL_ALL, spa, RW_WRITER); + spa_config_enter(spa, SCL_STATE_ALL, spa, RW_WRITER); vdev_free(vd); - spa_config_exit(spa, SCL_ALL, spa); + spa_config_exit(spa, SCL_STATE_ALL, spa); } /*