From babf3f9b6d9294b0a88457941d60af5d9d7b744d Mon Sep 17 00:00:00 2001 From: Massimo Maggi Date: Fri, 18 Jan 2013 09:44:09 -0800 Subject: [PATCH] Fix zpool on zvol deadlock Commit 65d56083b4617a4cade0cff68cbbaf68114169d6 fixes the lock inversion between spa_namespace_lock and bdev->bd_mutex but only for the first user of spa_namespace_lock: dmu_objset_own(). Later spa_namespace_lock gets acquired by dsl_prop_get_integer() though dsl_prop_get()->dsl_dataset_hold()->dsl_dir_open_spa()-> spa_open()->spa_open_common() without this "protection". By moving the mutex release after this second use, even this acquisition of the lock is "protected" by the ERESTARTSYS trick. Signed-off-by: Massimo Maggi Signed-off-by: Brian Behlendorf Closes #1220 --- module/zfs/zvol.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) diff --git a/module/zfs/zvol.c b/module/zfs/zvol.c index d4d533f..c6cfac2 100644 --- a/module/zfs/zvol.c +++ b/module/zfs/zvol.c @@ -920,24 +920,20 @@ zvol_first_open(zvol_state_t *zv) /* lie and say we're read-only */ error = dmu_objset_own(zv->zv_name, DMU_OST_ZVOL, 1, zvol_tag, &os); - - if (locked) - mutex_exit(&spa_namespace_lock); - if (error) - return (-error); + goto out_mutex; error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize); if (error) { - dmu_objset_disown(os, zvol_tag); - return (-error); + dmu_objset_disown(os, zvol_tag); + goto out_mutex; } zv->zv_objset = os; error = dmu_bonus_hold(os, ZVOL_OBJ, zvol_tag, &zv->zv_dbuf); if (error) { - dmu_objset_disown(os, zvol_tag); - return (-error); + dmu_objset_disown(os, zvol_tag); + goto out_mutex; } set_capacity(zv->zv_disk, volsize >> 9); @@ -946,13 +942,17 @@ zvol_first_open(zvol_state_t *zv) VERIFY(dsl_prop_get_integer(zv->zv_name, "readonly", &ro, NULL) == 0); if (ro || dmu_objset_is_snapshot(os)) { - set_disk_ro(zv->zv_disk, 1); - zv->zv_flags |= ZVOL_RDONLY; + set_disk_ro(zv->zv_disk, 1); + zv->zv_flags |= ZVOL_RDONLY; } else { - set_disk_ro(zv->zv_disk, 0); - zv->zv_flags &= ~ZVOL_RDONLY; + set_disk_ro(zv->zv_disk, 0); + zv->zv_flags &= ~ZVOL_RDONLY; } +out_mutex: + if (locked) + mutex_exit(&spa_namespace_lock); + return (-error); } -- 1.8.3.1