Always wait for txg sync when umounting dataset

Currently, when unmounting a filesystem, ZFS will only wait for a txg sync if the dataset is dirty and not readonly. However, this can be problematic in cases where a dataset is remounted readonly immediately before being unmounted, which often happens when the system is being shut down. Since encrypted datasets require that all I/O is completed before the dataset is disowned, this issue causes problems when write I/Os leak into the txgs after the dataset is disowned, which can happen when sync=disabled. This patch simply enforces that all dirty datasets should wait for a txg sync before umount completes. Fixes: openzfs#7753 Signed-off-by: Tom Caputi <[email protected]>
datto · Aug 16, 2018 · d26756d · d26756d
1 parent 4338c5c
commit d26756d
Showing 1 changed file with 1 addition and 2 deletions.
diff --git a/module/zfs/zfs_vfsops.c b/module/zfs/zfs_vfsops.c
@@ -1743,8 +1743,7 @@ zfsvfs_teardown(zfsvfs_t *zfsvfs, boolean_t unmounting)
 	/*
 	 * Evict cached data
 	 */
-	if (dsl_dataset_is_dirty(dmu_objset_ds(zfsvfs->z_os)) &&
-	    !zfs_is_readonly(zfsvfs))
+	if (dsl_dataset_is_dirty(dmu_objset_ds(zfsvfs->z_os)))
 		txg_wait_synced(dmu_objset_pool(zfsvfs->z_os), 0);
 	dmu_objset_evict_dbufs(zfsvfs->z_os);