On Mon, Feb 18, 2019 at 10:19:51AM +0100, Christoph Hellwig wrote: > The way we decided if an unwritten extent is considered a hole or data > is by checking if the page and/or blocks are marked uptodate, that is > contain valid data in the page cache. > > xfs/420 and xfs/421 try to exercise SEEK_HOLE / SEEK_DATA in the > presence of cowextsize preallocations over holes in the data fork. The > current XFS code never actually uses those for buffer writes, but a > pending patch changes that. For SEEK_HOLE / SEEK_DATA to work properly > in that case we also need to look at the COW fork in their > implementations and thus have to rely on the unwritten extent page cache > probing. But the tests for it ensure we do have valid data in the > pagecache by calling md5sum on the test files, and thus reading their > contents (including the zero-filled holes) in, and thus making them > all valid data. > > Fix that by dropping the page cache content after the md5sum calls. > > Signed-off-by: Christoph Hellwig <hch@xxxxxx> Hi Darrick, would you please help review this version of the fix as well? I basically have no idea about the implementation of the "pending patch" and what it changes.. Thanks a lot! Eryu > --- > tests/xfs/420 | 6 ++++++ > tests/xfs/421 | 6 ++++++ > 2 files changed, 12 insertions(+) > > diff --git a/tests/xfs/420 b/tests/xfs/420 > index a083a12b..34199637 100755 > --- a/tests/xfs/420 > +++ b/tests/xfs/420 > @@ -83,6 +83,8 @@ echo "Compare files" > md5sum $testdir/file1 | _filter_scratch > md5sum $testdir/file2 | _filter_scratch > md5sum $testdir/file3 | _filter_scratch > +# drop caches to make sure the page cache for the unwritten extents is clean > +echo 1 > /proc/sys/vm/drop_caches > > echo "CoW the shared part then write into the empty part" | tee -a $seqres.full > $XFS_IO_PROG -c "cowextsize" $testdir/file1 >> $seqres.full > @@ -106,6 +108,8 @@ echo "Compare files" > md5sum $testdir/file1 | _filter_scratch > md5sum $testdir/file2 | _filter_scratch > md5sum $testdir/file3 | _filter_scratch > +# drop caches to make sure the page cache for the unwritten extents is clean > +echo 1 > /proc/sys/vm/drop_caches > > echo "sync filesystem" | tee -a $seqres.full > sync > @@ -123,6 +127,8 @@ echo "Compare files" > md5sum $testdir/file1 | _filter_scratch > md5sum $testdir/file2 | _filter_scratch > md5sum $testdir/file3 | _filter_scratch > +# drop caches to make sure the page cache for the unwritten extents is clean > +echo 1 > /proc/sys/vm/drop_caches > > echo "Remount" | tee -a $seqres.full > _scratch_cycle_mount > diff --git a/tests/xfs/421 b/tests/xfs/421 > index a2734aba..374389bd 100755 > --- a/tests/xfs/421 > +++ b/tests/xfs/421 > @@ -83,6 +83,8 @@ echo "Compare files" > md5sum $testdir/file1 | _filter_scratch > md5sum $testdir/file2 | _filter_scratch > md5sum $testdir/file3 | _filter_scratch > +# drop caches to make sure the page cache for the unwritten extents is clean > +echo 1 > /proc/sys/vm/drop_caches > > echo "CoW the shared part then write into the empty part" | tee -a $seqres.full > $XFS_IO_PROG -c "cowextsize" $testdir/file1 >> $seqres.full > @@ -106,6 +108,8 @@ echo "Compare files" > md5sum $testdir/file1 | _filter_scratch > md5sum $testdir/file2 | _filter_scratch > md5sum $testdir/file3 | _filter_scratch > +# drop caches to make sure the page cache for the unwritten extents is clean > +echo 1 > /proc/sys/vm/drop_caches > > echo "sync filesystem" | tee -a $seqres.full > sync > @@ -123,6 +127,8 @@ echo "Compare files" > md5sum $testdir/file1 | _filter_scratch > md5sum $testdir/file2 | _filter_scratch > md5sum $testdir/file3 | _filter_scratch > +# drop caches to make sure the page cache for the unwritten extents is clean > +echo 1 > /proc/sys/vm/drop_caches > > echo "Remount" | tee -a $seqres.full > _scratch_cycle_mount > -- > 2.20.1 >
