Re: [PATCH] xfstests: test EROFS vs. EEXIST when creating on an RO filesystem

Eric Sandeen
2012-11-27T23:01:53Z

On 11/27/12 4:08 PM, Dave Chinner wrote:
> On Tue, Nov 27, 2012 at 03:16:39PM -0600, Eric Sandeen wrote:
>> TBH, I don't know if this is posix-specified, but I found out the
>> hard way that when trying to re-create existing files on a readonly
>> filesystem, some apps expect/handle EEXIST, but fail on EROFS.
>>
>> This will test mkdir, mknod, and symlinks for that behavior.
>>
>> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
>> ---
>>
>> Note: Think the command output is fixed enough, or should I
>> be grepping for keywords?
>
> Command output is good enough at this point.
>
>>
>> diff --git a/292 b/292
>> new file mode 100755
>> index 0000000..a14bb7f
>> --- /dev/null
>> +++ b/292
>> @@ -0,0 +1,73 @@
>> +#! /bin/bash
>> +# FS QA Test No. 292
>> +#
>> +# Tests for EEXIST (not EROFS) for inode creations, if
>> +# we ask to create an already-existing entity on an RO filesystem
>> +#
>> +#-----------------------------------------------------------------------
>> +# Copyright (c) 2012 Red Hat, Inc. All Rights Reserved.
>> +#
>> +# This program is free software; you can redistribute it and/or
>> +# modify it under the terms of the GNU General Public License as
>> +# published by the Free Software Foundation.
>> +#
>> +# This program is distributed in the hope that it would be useful,
>> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> +# GNU General Public License for more details.
>> +#
>> +# You should have received a copy of the GNU General Public License
>> +# along with this program; if not, write the Free Software Foundation,
>> +# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
>> +#-----------------------------------------------------------------------
>> +#
>> +# creator
>> +owner=sandeen@redhat.com
>> +
>> +seq=`basename $0`
>> +echo "QA output created by $seq"
>> +
>> +here=`pwd`
>> +tmp=/tmp/$$
>> +status=1 # failure is the default!
>> +trap "_cleanup; exit \$status" 0 1 2 3 15
>> +
>> +_cleanup()
>> +{
>> + cd /
>> + rm -f $tmp.*
>> +}
>> +
>> +# get standard environment, filters and checks
>> +. ./common.rc
>> +. ./common.filter
>> +
>> +# real QA test starts here
>> +
>> +# Modify as appropriate.
>> +_supported_fs generic
>> +_supported_os Linux
>> +_require_scratch
>> +
>> +THIS_TEST_DIR=$SCRATCH_MNT/$seq.test
>
> Confusing. $TEST_DIR is test filesystem mount point. This points
> something very similarly names at the scratch filesystem....

Meh, ok. $FOZZIE_BEAR_DIR or something; I'll change it.

>> +_create_files()
>> +{
>> + mknod $THIS_TEST_DIR/testnode c 1 3
>> + mkdir $THIS_TEST_DIR/testdir
>> + touch $THIS_TEST_DIR/testtarget
>> + ln -s $THIS_TEST_DIR/testtarget $THIS_TEST_DIR/testlink
>> +}
>> +
>> +_scratch_mount

Sigh, right. I started w/ the test dev but I'm not sure there's
a simple helper to remount it ro, so I was lazy. Then forgot to
add this.

> You need to mkfs the scratch device before using it. There is no
> guarantee that it is inmountable shape, or even contains the right
> filesytsem type when the test starts.
>
>> +
>> +rm -rf $THIS_TEST_DIR
>> +mkdir $THIS_TEST_DIR || _fail "Could not create dir for test"
>
> The error will dump into the output file and fail the golden output
> match. Using _fail means there's no .out.bad file for analysis of
> the failure.

>> +
>> +_create_files 2>&1 | _filter_scratch
>> +_scratch_mount -o remount,ro || _fail "Could not remount scratch readonly"
>
> Ditto.

OK.

Thanks,
-Eric

> Otherwise looks OK.
>
> Cheers,
>
> Dave.