[LTP] [PATCH v4] syscalls/sync_file_range: add partial file sync test-cases

[Naresh Kamboju]

Hi Caspar and Sumit,

> > > > > We encountered test failure in the second case in a debug kernel,
> > > > > reproducible about once out of 20 times run.
> > > >
> > > > Interesting case. Can you share results after applying below patch?
> > >
> > > Tested this patch, no TFAIL occured in debug kernel after 200+ times
> > > run, looks good to me. Thanks! Please add my
> >
> > From these results, the reason for the failure that you reported
> > earlier seems to be writes to the device during "tst_fill_fd()"
> > operation (they were found negligible/zero with normal kernel). But
> > it's strange to know that you didn't get any TFAIL after the patch as
> > I expected "Sync equals write" to fail.
> >
> > So can you also put following debug print and share logs of your test run?
>
> Retested with debug print, during my 1000-times run, pre-sync remains 0
> in all the other fs types except only ext4. For ext4 cases, pre-sync
> could be non-zero, e.g.:
>
>     Sync equals write: Synced 33554432, expected 33554432, pre-sync 0
>     Sync inside of write: Synced 17301504, expected 16777216, pre-sync 1308672
>     Sync overlaps with write: Synced 8650752, expected 8388608, pre-sync 1310720
>
> Note that pre-sync could be non-zero in `equals writes` case sometimes
> too, like another round below:
>
>     Sync equals write: Synced 34078720, expected 33554432, pre-sync 260096
>     Sync inside of write: Synced 17039360, expected 16777216, pre-sync 4980736
>     Sync overlaps with write: Synced 8912896, expected 8388608, pre-sync 1048576
>
> Such non-zero situation in ext4 case is reproducible ~10% of my
> 1000-times run.

sync_file_range02 test failure reproduced on mainline and stable rc branches
5.3, 4.19, 4.14 on arm64 and arm devices while testing on ext4.

output log,
--------------
tst_test.c:1179: INFO: Testing on ext2
tst_mkfs.c:90: INFO: Formatting /dev/loop0 with ext2 opts='' extra opts=''
mke2fs 1.43.8 (1-Jan-2018)
tst_test.c:1118: INFO: Timeout per run is 0h 15m 00s
sync_file_range02.c:71: PASS: Sync equals write
sync_file_range02.c:71: PASS: Sync inside of write
sync_file_range02.c:71: PASS: Sync overlaps with write
tst_test.c:1179: INFO: Testing on ext3
tst_mkfs.c:90: INFO: Formatting /dev/loop0 with ext3 opts='' extra opts=''
mke2fs 1.43.8 (1-Jan-2018)
Listened to connection for namespace 'tlxc' done
[ 1349.061989] EXT4-fs (loop0): mounting ext3 file system using the
ext4 subsystem
[ 1349.099564] EXT4-fs (loop0): mounted filesystem with ordered data
mode. Opts: (null)
tst_test.c:1118: INFO: Timeout per run is 0h 15m 00s
sync_file_range02.c:71: PASS: Sync equals write
Listened to connection for namespace 'tlxc' done
sync_file_range02.c:71: PASS: Sync inside of write
sync_file_range02.c:71: PASS: Sync overlaps with write
tst_test.c:1179: INFO: Testing on ext4
tst_mkfs.c:90: INFO: Formatting /dev/loop0 with ext4 opts='' extra opts=''
mke2fs 1.43.8 (1-Jan-2018)
[ 1362.579639] EXT4-fs (loop0): mounted filesystem with ordered data
mode. Opts: (null)
tst_test.c:1118: INFO: Timeout per run is 0h 15m 00s
sync_file_range02.c:74: FAIL: Sync equals write: Synced 36960256,
expected 33554432
Listened to connection for namespace 'tlxc' done
sync_file_range02.c:74: FAIL: Sync inside of write: Synced 20185088,
expected 16777216
sync_file_range02.c:71: PASS: Sync overlaps with write
Summary:
passed   7
failed   2

Full output log,
--------------------
https://lkft.validation.linaro.org/scheduler/job/983166#L15067

- Naresh