On Fri, Jan 28, 2022 at 08:27:00AM +0800, Qu Wenruo wrote: > In v5.11~v5.15 kernels, there is a regression in autodefrag that if a > cluster (up to 256K in size) has even a single hole, the whole cluster > will be rejected. > > This will greatly reduce the efficiency of autodefrag. > > The behavior is fixed in v5.16 by a full rework, although the rework > itself has other problems, it at least solves the problem. > > Here we add a test case to reproduce the case, where we have a 128K > cluster, the first half is fragmented extents which can be defragged. > The second half is hole. > > Make sure autodefrag can defrag the 64K part. > > Signed-off-by: Qu Wenruo <wqu@xxxxxxxx> Tried the test, and it succeeds here without the kernel fix applied. I've ran it 10 times, and it always passed without the kernel fix. Thanks. > --- > Changelog: > v2: > - Use the previously define _get_file_extent_sector() helper > This also removed some out-of-sync error messages > > - Trigger autodefrag using commit=1 mount option > No need for special purpose patch any more. > > - Use xfs_io -s to skip several sync calls > > - Shorten the subject of the commit > --- > tests/btrfs/256 | 80 +++++++++++++++++++++++++++++++++++++++++++++ > tests/btrfs/256.out | 2 ++ > 2 files changed, 82 insertions(+) > create mode 100755 tests/btrfs/256 > create mode 100644 tests/btrfs/256.out > > diff --git a/tests/btrfs/256 b/tests/btrfs/256 > new file mode 100755 > index 00000000..def83a15 > --- /dev/null > +++ b/tests/btrfs/256 > @@ -0,0 +1,80 @@ > +#! /bin/bash > +# SPDX-License-Identifier: GPL-2.0 > +# Copyright (C) 2022 SUSE Linux Products GmbH. All Rights Reserved. > +# > +# FS QA Test 256 > +# > +# Make sure btrfs auto defrag can properly defrag clusters which has hole > +# in the middle > +# > +. ./common/preamble > +_begin_fstest auto defrag quick > + > +. ./common/btrfs > +. ./common/filter > + > +# real QA test starts here > + > +# Modify as appropriate. > +_supported_fs generic > +_require_scratch > + > +# Needs 4K sectorsize, as larger sectorsize can change the file layout. > +_require_btrfs_support_sectorsize 4096 > + > +_scratch_mkfs >> $seqres.full > + > +# Need datacow to show which range is defragged, and we're testing > +# autodefrag > +_scratch_mount -o datacow,autodefrag > + > +# Create a layout where we have fragmented extents at [0, 64k) (sync write in > +# reserve order), then a hole at [64k, 128k) > +$XFS_IO_PROG -f -s -c "pwrite 48k 16k" -c "pwrite 32k 16k" \ > + -c "pwrite 16k 16k" -c "pwrite 0 16k" \ > + $SCRATCH_MNT/foobar >> $seqres.full > +truncate -s 128k $SCRATCH_MNT/foobar > + > +old_csum=$(_md5_checksum $SCRATCH_MNT/foobar) > +echo "=== File extent layout before autodefrag ===" >> $seqres.full > +$XFS_IO_PROG -c "fiemap -v" "$SCRATCH_MNT/foobar" >> $seqres.full > +echo "old md5=$old_csum" >> $seqres.full > + > +old_regular=$(_get_file_extent_sector "$SCRATCH_MNT/foobar" 0) > +old_hole=$(_get_file_extent_sector "$SCRATCH_MNT/foobar" 64k) > + > +# Now trigger autodefrag, autodefrag is triggered in the cleaner thread, > +# which will be woken up by commit thread > +_scratch_remount commit=1 > +sleep 3 > +sync > + > +new_csum=$(_md5_checksum $SCRATCH_MNT/foobar) > +new_regular=$(_get_file_extent_sector "$SCRATCH_MNT/foobar" 0) > +new_hole=$(_get_file_extent_sector "$SCRATCH_MNT/foobar" 64k) > + > +echo "=== File extent layout after autodefrag ===" >> $seqres.full > +$XFS_IO_PROG -c "fiemap -v" "$SCRATCH_MNT/foobar" >> $seqres.full > +echo "new md5=$new_csum" >> $seqres.full > + > +# In v5.11~v5.15 kernels, regular extents won't get defragged, and would trigger > +# the following output > +if [ $new_regular == $old_regular ]; then > + echo "regular extents didn't get defragged" > +fi > + > +# In v5.10 and earlier kernel, autodefrag may choose to defrag holes, > +# which should be avoided. > +if [ "$new_hole" != "$old_hole" ]; then > + echo "hole extents got defragged" > +fi > + > +# Defrag should not change file content > +if [ "$new_csum" != "$old_csum" ]; then > + echo "file content changed" > +fi > + > +echo "Silence is golden" > +# success, all done > +status=0 > +exit > diff --git a/tests/btrfs/256.out b/tests/btrfs/256.out > new file mode 100644 > index 00000000..7ee8e2e5 > --- /dev/null > +++ b/tests/btrfs/256.out > @@ -0,0 +1,2 @@ > +QA output created by 256 > +Silence is golden > -- > 2.34.1 >
