On 12/06/2017 10:17 PM, Eryu Guan wrote:
> On Wed, Dec 06, 2017 at 10:35:06AM -0600, Goldwyn Rodrigues wrote:
>>
>>
>> On 12/06/2017 04:05 AM, Eryu Guan wrote:
>>> On Wed, Nov 29, 2017 at 10:33:57AM -0600, Goldwyn Rodrigues wrote:
>>>> From: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
>>>>
>>>> Tests the RWF_NOWAIT flag so the I/O returns immediately with -EAGAIN
>>>> on a new file since it requires block allocation.
>>>>
>>>> It creates a file, syncs it, and overwrites the file with RWF_NOWAIT.
>>>> This should succeed.
>>>>
>>>> Finally, read the contents to make sure the overwrite is successful.
>>>>
>>>> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
>>>>
>>>> Changes since v1:
>>>> - Fix testdir name
>>>> - use of $XFS_IO_PROG instead of xfs_io
>>>> - check pwrite accepts -N
>>>>
>>>> Changes since v2:
>>>> - corrected test description and improved documentation
>>>> - new leaner look ;)
>>>> - rw group
>>>> ---
>>>> tests/generic/470 | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++
>>>> tests/generic/470.out | 13 +++++++++
>>>> tests/generic/group | 1 +
>>>> 3 files changed, 88 insertions(+)
>>>> create mode 100755 tests/generic/470
>>>> create mode 100644 tests/generic/470.out
>>>>
>>>> diff --git a/tests/generic/470 b/tests/generic/470
>>>> new file mode 100755
>>>> index 00000000..5580718b
>>>> --- /dev/null
>>>> +++ b/tests/generic/470
>>>> @@ -0,0 +1,74 @@
>>>> +#! /bin/bash
>>>> +# FS QA Test No. 470
>>>> +#
>>>> +# write a file with RWF_NOWAIT and it would fail because there are no
>>>> +# blocks allocated. Create a file with direct I/O and re-write it
>>>> +# using RWF_NOWAIT. I/O should finish within 50 microsecods since
>>>> +# block allocations are already performed.
>>>> +#
>>>> +#-----------------------------------------------------------------------
>>>> +# Copyright (c) 2017, SUSE Linux Products. 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
>>>> +#-----------------------------------------------------------------------
>>>> +
>>>> +seq=`basename $0`
>>>> +seqres=$RESULT_DIR/$seq
>>>> +echo "QA output created by $seq"
>>>> +
>>>> +here=`pwd`
>>>> +tmp=/tmp/$$
>>>> +status=1 # failure is the default!
>>>> +
>>>> +# get standard environment, filters and checks
>>>> +. ./common/rc
>>>> +. ./common/populate
>>>> +. ./common/filter
>>>> +. ./common/attr
>>>> +
>>>> +# real QA test starts here
>>>> +_supported_os Linux
>>>> +_require_odirect
>>>> +_require_test
>>>> +_require_xfs_io_command pwrite -N
>>>> +
>>>> +# Remove reminiscence of previously run tests
>>>> +testdir=$TEST_DIR/$seq
>>>> +if [ -e $testdir ]; then
>>>> + rm -Rf $testdir
>>>> +fi
>>>> +
>>>> +mkdir $testdir
>>>> +
>>>> +# Create a file with pwrite nowait (will fail with EAGAIN)
>>>> +$XFS_IO_PROG -f -d -c "pwrite -N -V 1 -b 1M 0 1M" $testdir/f1
>>>
>>> It's weird that I got "Operation not supported" message here and test
>>> failed as
>>>
>>> @@ -1,5 +1,5 @@
>>> QA output created by 470
>>> -pwrite: Resource temporarily unavailable
>>> +pwrite: Operation not supported
>>> wrote 8388608/8388608 bytes at offset 0
>>> XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
>>> RWF_NOWAIT time is within limits.
>>>
>>> I was using latest for-next branch of upstream xfsprogs, and a
>>> pre-v4.15-rc1 kernel shipped by Fedora rawhide. A simple test showed:
>>
>> What is the output of uname -a
>> It should be compatible with 4.13 onward. OTOH, _require_xfs_io_command
>> will catch that.
>
> Linux localhost 4.15.0-0.rc0.git6.1.fc28.x86_64 #1 SMP Mon Nov 20 18:08:48 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
>
> _require_xfs_io_command doesn't run "pwrite -N" with "-V 1" option, so
> test there passes, it only fails with vectors specified
>
> # rm /mnt/xfs/testfile
> # xfs_io -fdc "pwrite -N 0 4k" /mnt/xfs/testfile
> wrote 4096/4096 bytes at offset 0
> 4 KiB, 1 ops; 0.0000 sec (787.402 KiB/sec and 196.8504 ops/sec)
> # rm /mnt/xfs/testfile
> # xfs_io -fdc "pwrite -N -V 1 0 4k" /mnt/xfs/testfile
> pwrite: Operation not supported
>
> That's why I was asking if we should include "-V 1" in
> _require_xfs_io_command in patch 1.
>
I am all for including your suggestion in patch 1. However, it does not
explain two things:
1. Why is the error code in strace changing from -EAGAIN to -EOPNOTSUPP?
2. Why is it happening on a kernel version greater than 4.14?
Anyways, I shall add the changes and send it across again.
>>
>>>
>>> rm -f /mnt/xfs/testfile
>>> xfs_io -fdc "pwrite -N -V 1 -b 4k 0 4k" /mnt/xfs/testfile
>>> pwrite: Operation not supported
>>
>> For kernels which do not support RWF_NOWAIT, it will return EOPNOTSUPP.
>>
>>>
>>> But an strace run showed pwritev2 did -1 and set EAGAIN as errno, but
>>> printed "Operation not supported" as error message:
>>> ...
>>> pwritev2(3, [{iov_base="\315\315\315\315\315\315\315\315\315\315\315\315\315\315\315\315\315\315\315\315\315\315\315\315\315\315\315\315\315\315\315\315"..., iov_len=4096}], 1, 0, RWF_NOWAIT) = -1 EAGAIN (Resource temporarily unavailable)
>>> dup(2) = 4
>>> fcntl(4, F_GETFL) = 0x402 (flags O_RDWR|O_APPEND)
>>> openat(AT_FDCWD, "/usr/share/locale/en_US.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
>>> openat(AT_FDCWD, "/usr/share/locale/en_US.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
>>> openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
>>> openat(AT_FDCWD, "/usr/share/locale/en.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
>>> openat(AT_FDCWD, "/usr/share/locale/en.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
>>> openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
>>> fstat(4, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 0), ...}) = 0
>>> write(4, "pwrite: Operation not supported\n", 32pwrite: Operation not supported
>>> ...
>>>
>>> Not sure what happened yet, did I miss anything?
>>
>> Did you trim any lines in between? If you had another error in between
>> before you collect -EAGAIN, it most likely overwrote the value. Not sure
>> what is going on though..
>
> No, I didn't trim any lines in between.
>
>>
>>>
>>>> +
>>>> +# Write the file without nowait
>>>> +$XFS_IO_PROG -f -d -c "pwrite -S 0xaa -W -w -V 1 -b 1M 0 8M" $testdir/f1 | _filter_xfs_io
>>>
>>> I think "-w" (fdatasync) can be removed? We already use "-W" (fsync) here.
>>>
>>>> +
>>>> +time_taken=`$XFS_IO_PROG -d -c "pwrite -S 0xbb -N -V 1 -b 1M 2M 1M" $testdir/f1 | awk '/^1/ {print $5}'`
>>>> +
>>>> +# RWF_NOWAIT should finish within a short period of time. Anything longer
>>>> +# means it is waiting for something in the kernel which would be a fail.
>>>> +if (( $(echo "$time_taken < 0.05" | bc -l) )); then
>>>
>>> Better to describe where does this 0.05 come from.
>>>
>>
>> No significance as such, but a conservative value for the operation to
>> be completed. If you want me to explicitly put 50 ms, I can.
>
> There should be a reason for this 50ms estimation. IMHO, as simple as "a
> conservative value for the operation to be completed" would be better
> than nothing :)
>
> Thanks,
> Eryu
>
--
Goldwyn
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