diff options
author | Darrick J. Wong <djwong@kernel.org> | 2022-03-15 20:30:20 -0700 |
---|---|---|
committer | Eryu Guan <guaneryu@gmail.com> | 2022-04-10 20:33:04 +0800 |
commit | bc593bd327e0c1e7ed67051d88c81fe3d09d9536 (patch) | |
tree | 9ccfd8873b3263e23d9c6a5c946bd769030e1215 | |
parent | 58331382174eaa8aedd72223906fb1265b450687 (diff) | |
download | xfstests-dev-bc593bd327e0c1e7ed67051d88c81fe3d09d9536.tar.gz |
xfs/420: fix occasional test failures due to pagecache readahead
Every now and then, this test fails with this golden output:
--- xfs/420.out
+++ xfs/420.out.bad
@@ -29,7 +29,7 @@
Whence Result
DATA 0
HOLE 131072
-DATA 196608
+DATA 192512
HOLE 262144
Compare files
c2803804acc9936eef8aab42c119bfac SCRATCH_MNT/test-420/file1
Curiously, the file checksums always match, and it's not *forbidden* for
the page cache to have a page backing an unwritten extent that hasn't
been written.
The condition that this test cares about is that block 3 (192k-256k) are
reported by SEEK_DATA as data even if the data fork has a hole and the
COW fork has an unwritten extent. Matthew Wilcox thinks this is a side
effect of readahead.
To fix this occasional false failure, call SEEK_DATA and SEEK_HOLE only
on the offsets that we care about.
Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
-rwxr-xr-x | tests/xfs/420 | 33 |
1 files changed, 21 insertions, 12 deletions
diff --git a/tests/xfs/420 b/tests/xfs/420 index 12b1758808..d38772c9d9 100755 --- a/tests/xfs/420 +++ b/tests/xfs/420 @@ -50,6 +50,24 @@ _scratch_mount >> $seqres.full 2>&1 testdir=$SCRATCH_MNT/test-$seq mkdir $testdir +# pagecache readahead can sometimes cause extra pages to be inserted into the +# file mapping where we have an unwritten extent in the COW fork. Call lseek +# on each $blksz offset that interests us (as opposed to the whole file) so +# that these extra pages are not disclosed. +# +# The important thing we're testing is that SEEK_DATA reports block 3 as data +# when the COW fork has an unwritten mapping and the data fork has a hole. +exercise_lseek() { + echo "Seek holes and data in file1" + $XFS_IO_PROG -c "seek -d 0" $testdir/file1 + $XFS_IO_PROG -c "seek -h $((2 * blksz))" $testdir/file1 | sed -e '/Whence/d' + echo "Seek holes and data in file2" + $XFS_IO_PROG -c "seek -d 0" $testdir/file2 + $XFS_IO_PROG -c "seek -h $((2 * blksz))" $testdir/file2 | sed -e '/Whence/d' + $XFS_IO_PROG -c "seek -d $((3 * blksz))" $testdir/file2 | sed -e '/Whence/d' + $XFS_IO_PROG -c "seek -h $((4 * blksz))" $testdir/file2 | sed -e '/Whence/d' +} + blksz=65536 nr=8 filesize=$((blksz * nr)) @@ -83,10 +101,7 @@ $XFS_IO_PROG -c "bmap -ev" -c "bmap -cv" $testdir/file1 >> $seqres.full 2>&1 $XFS_IO_PROG -c "bmap -ev" -c "bmap -cv" $testdir/file2 >> $seqres.full 2>&1 $XFS_IO_PROG -c "bmap -ev" -c "bmap -cv" $testdir/file3 >> $seqres.full 2>&1 -echo "Seek holes and data in file1" -$XFS_IO_PROG -c "seek -a -r 0" $testdir/file1 -echo "Seek holes and data in file2" -$XFS_IO_PROG -c "seek -a -r 0" $testdir/file2 +exercise_lseek echo "Compare files" md5sum $testdir/file1 | _filter_scratch @@ -102,10 +117,7 @@ $XFS_IO_PROG -c "bmap -ev" -c "bmap -cv" $testdir/file1 >> $seqres.full 2>&1 $XFS_IO_PROG -c "bmap -ev" -c "bmap -cv" $testdir/file2 >> $seqres.full 2>&1 $XFS_IO_PROG -c "bmap -ev" -c "bmap -cv" $testdir/file3 >> $seqres.full 2>&1 -echo "Seek holes and data in file1" -$XFS_IO_PROG -c "seek -a -r 0" $testdir/file1 -echo "Seek holes and data in file2" -$XFS_IO_PROG -c "seek -a -r 0" $testdir/file2 +exercise_lseek echo "Compare files" md5sum $testdir/file1 | _filter_scratch @@ -121,10 +133,7 @@ $XFS_IO_PROG -c "bmap -ev" -c "bmap -cv" $testdir/file1 >> $seqres.full 2>&1 $XFS_IO_PROG -c "bmap -ev" -c "bmap -cv" $testdir/file2 >> $seqres.full 2>&1 $XFS_IO_PROG -c "bmap -ev" -c "bmap -cv" $testdir/file3 >> $seqres.full 2>&1 -echo "Seek holes and data in file1" -$XFS_IO_PROG -c "seek -a -r 0" $testdir/file1 -echo "Seek holes and data in file2" -$XFS_IO_PROG -c "seek -a -r 0" $testdir/file2 +exercise_lseek echo "Compare files" md5sum $testdir/file1 | _filter_scratch |