[PATCH] generic/623: fix test for runing on overlayfs

[Amir Goldstein <amir73il@gmail.com>]

For this test to run on overlayfs we open a different file to perform
shutdown+fsync while keeping the writeback target file open.

We should probably perform fsync on the writeback target file, but
the bug is reproduced on xfs and overlayfs+xfs also as is.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---

Zorro,

I tested that this test passes for both xfs and overlayfs+xfs on v5.18
and tested that both configs fail with the same warning on v5.10.109.

I tried changing fsync to syncfs for the test to be more correct in the
overlayfs case, but then golden output of xfs and overlayfs+xfs differ
and that would need some more output filtering (or disregarding output
completely).

Since this minimal change does the job and does not change test behavior
on xfs on any of the tested kernels, I thought it might be good enough.

Thanks,
Amir.

 tests/generic/623 | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tests/generic/623 b/tests/generic/623
index ea016d91..bb36ad25 100755
--- a/tests/generic/623
+++ b/tests/generic/623
@@ -24,10 +24,13 @@ _scratch_mount
 # XFS had a regression where it failed to check shutdown status in the fault
 # path. This produced an iomap warning because writeback failure clears Uptodate
 # status on the page.
+# For this test to run on overlayfs we open a different file to perform
+# shutdown+fsync while keeping the writeback target file open.
 file=$SCRATCH_MNT/file
 $XFS_IO_PROG -fc "pwrite 0 4k" -c fsync $file | _filter_xfs_io
 ulimit -c 0
-$XFS_IO_PROG -x -c "mmap 0 4k" -c "mwrite 0 4k" -c shutdown -c fsync \
+$XFS_IO_PROG -x -c "mmap 0 4k" -c "mwrite 0 4k" \
+	-c "open $(_scratch_shutdown_handle)" -c shutdown -c fsync \
 	-c "mwrite 0 4k" $file | _filter_xfs_io
 
 # success, all done
-- 
2.25.1