ZTS: Improve enospc tests

The enospc_002_pos test case would frequently fail due a command
succeeding when it was expected to fail due to lack of space.
In order to make this far less likely, files are created across
multiple transaction groups in order to consume as many unused
blocks as possible.

The dependency that the tests run on a partitioned block device
has been removed.  It's simpler to use sparse files.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #7663

tests/test-runner/bin/zts-report.py

@@ -105,6 +105,14 @@ user_ns_reason = 'Kernel user namespace support required'
 #
 rewind_reason = 'Arbitrary pool rewind is not guaranteed'
 
+#
+# Some tests may by structured in a way that relies on exact knowledge
+# of how much free space in available in a pool.  These tests cannot be
+# made completely reliable because the internal details of how free space
+# is managed are not exposed to user space.
+#
+enospc_reason = 'Exact free space reporting is not guaranteed'
+
 #
 # Some tests are not applicable to Linux or need to be updated to operate
 # in the manor required by Linux.  Any tests which are skipped for this
@@ -235,8 +243,7 @@ maybe = {
     'inuse/inuse_009_pos': ['SKIP', disk_reason],
     'largest_pool/largest_pool_001_pos': ['FAIL', known_reason],
     'pyzfs/pyzfs_unittest': ['SKIP', python_deps_reason],
-    'no_space/setup': ['SKIP', disk_reason],
-    'no_space/enospc_002_pos': ['FAIL', known_reason],
+    'no_space/enospc_002_pos': ['FAIL', enospc_reason],
     'projectquota/setup': ['SKIP', exec_reason],
     'reservation/reservation_018_pos': ['FAIL', '5642'],
     'rsend/rsend_019_pos': ['FAIL', '6086'],

tests/zfs-tests/tests/functional/no_space/cleanup.ksh

@@ -33,22 +33,7 @@
 
 verify_runnable "global"
 
-DISK=${DISKS%% *}
-
-ismounted "$TESTPOOL/$TESTFS"
-(( $? == 0 )) && \
-        log_must zfs umount $TESTDIR
-
-destroy_pool $TESTPOOL
-
-if is_mpath_device $DISK; then
-	delete_partitions
-fi
-
-#
-# Remove 100mb partition.
-#
-create_pool dummy$$ "$DISK"
-destroy_pool dummy$$
+default_cleanup_noexit
+log_must rm -f $DISK_SMALL $DISK_LARGE
 
 log_pass

tests/zfs-tests/tests/functional/no_space/enospc.cfg

@@ -28,15 +28,12 @@
 # Copyright (c) 2013 by Delphix. All rights reserved.
 #
 
-export TESTFILE0=testfile0.$$
-export TESTFILE1=testfile1.$$
+DISK_SMALL=${TEST_BASE_DIR%%/}/vdev_small
+DISK_LARGE=${TEST_BASE_DIR%%/}/vdev_large
 
-export SIZE=100mb
+export SIZE_SMALL=100m
+export SIZE_LARGE=512m
 export ENOSPC=28
 export BLOCKSZ=8192
 export NUM_WRITES=65536
 export DATA=0
-
-export DISKSARRAY=$DISKS
-export DISK_ARRAY_NUM=$(echo ${DISKS} | nawk '{print NF}')
-set_device_dir

tests/zfs-tests/tests/functional/no_space/enospc_001_pos.ksh

@@ -48,13 +48,14 @@ verify_runnable "both"
 
 function cleanup
 {
-	rm -f $TESTDIR/$TESTFILE0
-	rm -f $TESTDIR/$TESTFILE1
+	default_cleanup_noexit
 }
 
 log_onexit cleanup
 
 log_assert "ENOSPC is returned when file system is full."
+
+default_setup_noexit $DISK_SMALL
 log_must zfs set compression=off $TESTPOOL/$TESTFS
 
 log_note "Writing file: $TESTFILE0 until ENOSPC."

tests/zfs-tests/tests/functional/no_space/enospc_002_pos.ksh

@@ -28,18 +28,36 @@
 
 verify_runnable "both"
 
+function cleanup
+{
+	log_must_busy zpool destroy -f $TESTPOOL
+}
+
+log_onexit cleanup
+
 log_assert "ENOSPC is returned when file system is full."
-sync
+
+default_setup_noexit $DISK_SMALL
 log_must zfs set compression=off $TESTPOOL/$TESTFS
 log_must zfs snapshot $TESTPOOL/$TESTFS@snap
 
-log_note "Writing file: $TESTFILE0 until ENOSPC."
-file_write -o create -f $TESTDIR/$TESTFILE0 -b $BLOCKSZ \
-    -c $NUM_WRITES -d $DATA
-ret=$?
+#
+# Completely fill the pool in order to ensure the commands below will more
+# reliably succeed or fail as a result of lack of space.  Care is taken to
+# force multiple transaction groups to ensure as many recently freed blocks
+# as possible are reallocated.
+#
+log_note "Writing files until ENOSPC."
 
-(( $ret != $ENOSPC )) && \
-    log_fail "$TESTFILE0 returned: $ret rather than ENOSPC."
+for i in $(seq 30); do
+	file_write -o create -f $TESTDIR/file.$i -b $BLOCKSZ \
+	    -c $NUM_WRITES -d $DATA
+	ret=$?
+	(( $ret != $ENOSPC )) && \
+	    log_fail "file.$i returned: $ret rather than ENOSPC."
+
+	log_must zpool sync -f
+done
 
 log_mustnot_expect space zfs create $TESTPOOL/$TESTFS/subfs
 log_mustnot_expect space zfs clone $TESTPOOL/$TESTFS@snap $TESTPOOL/clone

tests/zfs-tests/tests/functional/no_space/enospc_003_pos.ksh

@@ -45,19 +45,13 @@ verify_runnable "both"
 function cleanup
 {
 	log_must zpool destroy $TESTPOOL1
-	log_must rm -f $disk
 }
 
 log_onexit cleanup
 
 log_assert "ENOSPC is returned on pools with large physical block size"
 
-disk=$TEST_BASE_DIR/$FILEDISK0
-# we need a device big enough to test this or failure will not trigger
-size="512m"
-log_must mkfile $size $disk
-
-log_must zpool create $TESTPOOL1 -o ashift=13 $disk
+log_must zpool create $TESTPOOL1 -o ashift=13 $DISK_LARGE
 log_must zfs set mountpoint=$TESTDIR $TESTPOOL1
 log_must zfs set compression=off $TESTPOOL1
 log_must zfs set recordsize=512 $TESTPOOL1

tests/zfs-tests/tests/functional/no_space/setup.ksh

@@ -34,23 +34,7 @@
 
 verify_runnable "global"
 
-if ! $(is_physical_device $DISKS) ; then
-	log_unsupported "This directory cannot be run on raw files."
-fi
+log_must truncate -s $SIZE_SMALL $DISK_SMALL
+log_must truncate -s $SIZE_LARGE $DISK_LARGE
 
-DISK=${DISKS%% *}
-
-log_must set_partition 0 "" $SIZE $DISK
-
-if is_linux; then
-	if ( is_mpath_device $DISK ) && [[ -z $(echo $DISK | awk 'substr($1,18,1)\
-	    ~ /^[[:digit:]]+$/') ]] || ( is_real_device $DISK ); then
-		default_setup $DISK"1"
-	elif ( is_mpath_device $DISK || is_loop_device $DISK ); then
-		default_setup $DISK"p1"
-	else
-		log_fail "$DISK not supported for partitioning."
-	fi
-else
-	default_setup $DISK"s0"
-fi
+log_pass