mirror_zfs/tests
Andriy Tkachuk b403040c4c
draid: fix data corruption after disk clear
Currently, when there there are several faulted disks with attached
dRAID spares, and one of those disks is cleared from errors (zpool
clear), followed by its spare being detached, the data in all the
remaining spares that were attached while the cleared disk was in
FAULTED state might get corrupted (which can be seen by running scrub).
In some cases, when too many disks get cleared at a time, this can
result in data corruption/loss.

dRAID spare is a virtual device whose blocks are distributed among
other disks. Those disks can be also in FAULTED state with attached
spares on their own. When a disk gets sequentially resilvered (rebuilt),
the changes made by that resilvering won't get captured in the DTL
(Dirty Time Log) of other FAULTED disks with the attached spares to
which the data is written during the resilvering (as it would normally
be done for the changes made by the user if a new file is written or
some existing one is deleted). It is because sequential resilvering
works on the block level, without touching or looking into metadata,
so it doesn't know anything about the old BPs or transactions groups
that it is resilvering. So later on, when that disk gets cleared
from errors and healing resilvering is trying to sync all the data
from its spare onto it, all the changes made on its spare during the
resilvering of other disks will be missed because they won't be
captured in its DTL. That's why other dRAID spares may get corrupted.

Here's another way to explain it that might be helpful. Imagine a
scenario:

1. d1 fails and gets resilvered to some spare s1 - OK.
2. d2 fails and gets sequentially resilvered on draid spare s2. Now,
   in some slices, s2 would map to d1, which is failed. But d1 has s1
   spare attached, so the data from that resilvering goes to s1, but
   not recorded in d1's DTL.
3. Now, d1 gets cleared and its s1 gets detached. All the changes
   done by the user (writes or deletions) have their txgs captured
   in d1's DTL, so they will be resilvered by the healing resilver
   from its spare (s1) - that part works fine. But the data which
   was written during resilvering of d2 and went to s1 - that one
   will be missed from d1's DTL and won't get resilvered to it. So
   here we are:
4. s2 under d2 is corrupted in the slices which map to d1, because
   d1 doesn't have that data resilvered from s1.

Now, if there are more failed disks with draid spares attached which
were sequentially resilvered while d1 was failed, d3+s3, d4+s4 and
so on - all their spares will be corrupted. Because, in some slices,
each of them will map to d1 which will miss their data.

Solution: add all known txgs starting from TXG_INITIAL to DTLs of
non-writable devices during sequential resilvering so when healing
resilver starts on disk clear, it would be able to check and heal
blocks from all txgs.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Reviewed-by: Akash B <akash-b@hpe.com>
Signed-off-by: Andriy Tkachuk <andriy.tkachuk@seagate.com>
Closes #18286
Closes #18294
2026-03-11 14:54:20 -07:00
..
runfiles zfs_main: create, clone, rename: accept -pp for non-mountable parents 2026-03-09 14:50:18 -07:00
test-runner ZTS: Add additional exceptions 2026-03-03 11:18:46 -08:00
zfs-tests draid: fix data corruption after disk clear 2026-03-11 14:54:20 -07:00
Makefile.am build: add SPDX license tags to build system files 2026-01-08 15:08:03 -08:00
README.md tests: README: note non-default mountd requirement 2022-04-01 17:57:45 -07:00

ZFS Test Suite README

1) Building and installing the ZFS Test Suite

The ZFS Test Suite runs under the test-runner framework. This framework is built along side the standard ZFS utilities and is included as part of zfs-test package. The zfs-test package can be built from source as follows:

$ ./configure
$ make pkg-utils

The resulting packages can be installed using the rpm or dpkg command as appropriate for your distributions. Alternately, if you have installed ZFS from a distributions repository (not from source) the zfs-test package may be provided for your distribution.

- Installed from source
$ rpm -ivh ./zfs-test*.rpm, or
$ dpkg -i ./zfs-test*.deb,

- Installed from package repository
$ yum install zfs-test
$ apt-get install zfs-test

2) Running the ZFS Test Suite

The pre-requisites for running the ZFS Test Suite are:

  • Three scratch disks
    • Specify the disks you wish to use in the $DISKS variable, as a space delimited list like this: DISKS='vdb vdc vdd'. By default the zfs-tests.sh script will construct three loopback devices to be used for testing: DISKS='loop0 loop1 loop2'.
  • A non-root user with a full set of basic privileges and the ability to sudo(8) to root without a password to run the test.
  • Specify any pools you wish to preserve as a space delimited list in the $KEEP variable. All pools detected at the start of testing are added automatically.
  • The ZFS Test Suite will add users and groups to test machine to verify functionality. Therefore it is strongly advised that a dedicated test machine, which can be a VM, be used for testing.
  • On FreeBSD, mountd(8) must use /etc/zfs/exports as one of its export files by default this can be done by setting zfs_enable=yes in /etc/rc.conf.

Once the pre-requisites are satisfied simply run the zfs-tests.sh script:

$ /usr/share/zfs/zfs-tests.sh

Alternately, the zfs-tests.sh script can be run from the source tree to allow developers to rapidly validate their work. In this mode the ZFS utilities and modules from the source tree will be used (rather than those installed on the system). In order to avoid certain types of failures you will need to ensure the ZFS udev rules are installed. This can be done manually or by ensuring some version of ZFS is installed on the system.

$ ./scripts/zfs-tests.sh

The following zfs-tests.sh options are supported:

-v          Verbose zfs-tests.sh output When specified additional
            information describing the test environment will be logged
            prior to invoking test-runner.  This includes the runfile
            being used, the DISKS targeted, pools to keep, etc.

-q          Quiet test-runner output.  When specified it is passed to
            test-runner(1) which causes output to be written to the
            console only for tests that do not pass and the results
            summary.

-x          Remove all testpools, dm, lo, and files (unsafe).  When
            specified the script will attempt to remove any leftover
            configuration from a previous test run.  This includes
            destroying any pools named testpool, unused DM devices,
            and loopback devices backed by file-vdevs.  This operation
            can be DANGEROUS because it is possible that the script
            will mistakenly remove a resource not related to the testing.

-k          Disable cleanup after test failure.  When specified the
            zfs-tests.sh script will not perform any additional cleanup
            when test-runner exists.  This is useful when the results of
            a specific test need to be preserved for further analysis.

-f          Use sparse files directly instead of loopback devices for
            the testing.  When running in this mode certain tests will
            be skipped which depend on real block devices.

-c          Only create and populate constrained path

-I NUM      Number of iterations

-d DIR      Create sparse files for vdevs in the DIR directory.  By
            default these files are created under /var/tmp/.
            This directory must be world-writable.

-s SIZE     Use vdevs of SIZE (default: 4G)

-r RUNFILES Run tests in RUNFILES (default: common.run,linux.run)

-t PATH     Run single test at PATH relative to test suite

-T TAGS     Comma separated list of tags (default: 'functional')

-u USER     Run single test as USER (default: root)

The ZFS Test Suite allows the user to specify a subset of the tests via a runfile or list of tags.

The format of the runfile is explained in test-runner(1), and the files that zfs-tests.sh uses are available for reference under /usr/share/zfs/runfiles. To specify a custom runfile, use the -r option:

$ /usr/share/zfs/zfs-tests.sh -r my_tests.run

Otherwise user can set needed tags to run only specific tests.

3) Test results

While the ZFS Test Suite is running, one informational line is printed at the end of each test, and a results summary is printed at the end of the run. The results summary includes the location of the complete logs, which is logged in the form /var/tmp/test_results/[ISO 8601 date]. A normal test run launched with the zfs-tests.sh wrapper script will look something like this:

$ /usr/share/zfs/zfs-tests.sh -v -d /tmp/test

--- Configuration ---
Runfile:         /usr/share/zfs/runfiles/linux.run
STF_TOOLS:       /usr/share/zfs/test-runner
STF_SUITE:       /usr/share/zfs/zfs-tests
STF_PATH:        /var/tmp/constrained_path.G0Sf
FILEDIR:         /tmp/test
FILES:           /tmp/test/file-vdev0 /tmp/test/file-vdev1 /tmp/test/file-vdev2
LOOPBACKS:       /dev/loop0 /dev/loop1 /dev/loop2
DISKS:           loop0 loop1 loop2
NUM_DISKS:       3
FILESIZE:        4G
ITERATIONS:      1
TAGS:            functional
Keep pool(s):    rpool


/usr/share/zfs/test-runner/bin/test-runner.py  -c /usr/share/zfs/runfiles/linux.run \
    -T functional -i /usr/share/zfs/zfs-tests -I 1
Test: /usr/share/zfs/zfs-tests/tests/functional/arc/setup (run as root) [00:00] [PASS]
...more than 1100 additional tests...
Test: /usr/share/zfs/zfs-tests/tests/functional/zvol/zvol_swap/cleanup (run as root) [00:00] [PASS]

Results Summary
SKIP	  52
PASS	 1129

Running Time:	02:35:33
Percent passed:	95.6%
Log directory:	/var/tmp/test_results/20180515T054509

4) Example of adding and running test-case (zpool_example)

This broadly boils down to 5 steps

  1. Create/Set password-less sudo for user running test case.
  2. Edit configure.ac, Makefile.am appropriately
  3. Create/Modify .run files
  4. Create actual test-scripts
  5. Run Test case

Will look at each of them in depth.

  • Set password-less sudo for 'Test' user as test script cannot be run as root

  • Edit file configure.ac and include line under AC_CONFIG_FILES section

      tests/zfs-tests/tests/functional/cli_root/zpool_example/Makefile
    
  • Edit file tests/runfiles/Makefile.am and add line zpool_example.

      pkgdatadir = $(datadir)/@PACKAGE@/runfiles
      dist_pkgdata_DATA = \
        zpool_example.run \
        common.run \
        freebsd.run \
        linux.run \
        longevity.run \
        perf-regression.run \
        sanity.run \
        sunos.run
    
  • Create file tests/runfiles/zpool_example.run. This defines the most common properties when run with test-runner.py or zfs-tests.sh.

      [DEFAULT]
      timeout = 600
      outputdir = /var/tmp/test_results
      tags = ['functional']
    
      tests = ['zpool_example_001_pos']
    

    If adding test-case to an already existing suite the runfile would already be present and it needs to be only updated. For example, adding zpool_example_002_pos to the above runfile only update the "tests =" section of the runfile as shown below

      [DEFAULT]
      timeout = 600
      outputdir = /var/tmp/test_results
      tags = ['functional']
    
      tests = ['zpool_example_001_pos', 'zpool_example_002_pos']
    
  • Edit tests/zfs-tests/tests/functional/cli_root/Makefile.am and add line under SUBDIRS.

      zpool_example \ (Make sure to escape the line end as there will be other folders names following)
    
  • Create new file tests/zfs-tests/tests/functional/cli_root/zpool_example/Makefile.am the contents of the file could be as below. What it says it that now we have a test case zpool_example_001_pos.ksh

      pkgdatadir = $(datadir)/@PACKAGE@/zfs-tests/tests/functional/cli_root/zpool_example
      dist_pkgdata_SCRIPTS = \
        zpool_example_001_pos.ksh
    
  • We can now create our test-case zpool_example_001_pos.ksh under tests/zfs-tests/tests/functional/cli_root/zpool_example/.

    # DESCRIPTION:
    #	zpool_example Test
    #
    # STRATEGY:
    #	1. Demo a very basic test case
    #
    
    DISKS_DEV1="/dev/loop0"
    DISKS_DEV2="/dev/loop1"
    TESTPOOL=EXAMPLE_POOL
    
    function cleanup
    {
    	# Cleanup
    	destroy_pool $TESTPOOL
    	log_must rm -f $DISKS_DEV1
    	log_must rm -f $DISKS_DEV2
    }
    
    log_assert "zpool_example"
    # Run function "cleanup" on exit
    log_onexit cleanup
    
    # Prep backend device
    log_must dd if=/dev/zero of=$DISKS_DEV1 bs=512 count=140000
    log_must dd if=/dev/zero of=$DISKS_DEV2 bs=512 count=140000
    
    # Create pool
    log_must zpool create $TESTPOOL $type $DISKS_DEV1 $DISKS_DEV2
    
    log_pass "zpool_example"
    
  • Run Test case, which can be done in two ways. Described in detail above in section 2.

    • test-runner.py (This takes run file as input. See zpool_example.run)
    • zfs-tests.sh. Can execute the run file or individual tests