On Wed, Oct 30, 2024 at 12:49 AM Anand Jain <anand.jain@xxxxxxxxxx> wrote:
>
> On 30/10/24 01:23, fdmanana@xxxxxxxxxx wrote:
> > From: Filipe Manana <fdmanana@xxxxxxxx>
> >
> > Test that defrag merges adjacent extents that are contiguous.
> > This exercises a regression fixed by a patchset for the kernel that is
> > comprissed of the following patches:
> >
> > btrfs: fix extent map merging not happening for adjacent extents
> > btrfs: fix defrag not merging contiguous extents due to merged extent maps
> >
> > Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
> > ---
> > tests/btrfs/325 | 80 +++++++++++++++++++++++++++++++++++++++++++++
> > tests/btrfs/325.out | 22 +++++++++++++
> > 2 files changed, 102 insertions(+)
> > create mode 100755 tests/btrfs/325
> > create mode 100644 tests/btrfs/325.out
> >
> > diff --git a/tests/btrfs/325 b/tests/btrfs/325
> > new file mode 100755
> > index 00000000..0b1ab3c2
> > --- /dev/null
> > +++ b/tests/btrfs/325
> > @@ -0,0 +1,80 @@
> > +#! /bin/bash
> > +# SPDX-License-Identifier: GPL-2.0
> > +# Copyright (C) 2024 SUSE Linux Products GmbH. All Rights Reserved.
> > +#
> > +# FS QA Test 325
> > +#
> > +# Test that defrag merges adjacent extents that are contiguous.
> > +#
> > +. ./common/preamble
> > +_begin_fstest auto quick preallocrw defrag
> > +
> > +. ./common/filter
> > +
> > +_require_scratch
> > +_require_btrfs_command inspect-internal dump-tree
> > +_require_xfs_io_command "falloc"
> > +
> > +_fixed_by_kernel_commit xxxxxxxxxxxx \
> > + "btrfs: fix extent map merging not happening for adjacent extents"
> > +_fixed_by_kernel_commit xxxxxxxxxxxx \
> > + "btrfs: fix defrag not merging contiguous extents due to merged extent maps"
> > +
> > +count_file_extent_items()
> > +{
> > + # We count file extent extent items through dump-tree instead of using
> > + # fiemap because fiemap merges adjacent extent items when they are
> > + # contiguous.
> > + # We unmount because all metadata must be ondisk for dump-tree to see
> > + # it and work correctly.
> > + _scratch_unmount
> > + $BTRFS_UTIL_PROG inspect-internal dump-tree -t 5 $SCRATCH_DEV | \
> > + grep EXTENT_DATA | wc -l
> > + _scratch_mount
> > +}
> > +
> > +_scratch_mkfs >>$seqres.full 2>&1 || _fail "mkfs failed"
> > +_scratch_mount
> > +
> > +# Create a file with a size of 256K and 4 written extents of 64K each.
> > +# We fallocate to guarantee exact extent size, even if compression mount
> > +# option is give, and write to them because defrag skips prealloc extents.
> > +$XFS_IO_PROG -f -c "falloc 0 64K" \
> > + -c "pwrite -S 0xab 0 64K" \
> > + -c "falloc 64K 64K" \
> > + -c "pwrite -S 0xcd 64K 64K" \
> > + -c "falloc 128K 64K" \
> > + -c "pwrite -S 0xef 128K 64K" \
> > + -c "falloc 192K 64K" \
> > + -c "pwrite -S 0x73 192K 64K" \
> > + $SCRATCH_MNT/foo | _filter_xfs_io
> > +
> > +echo -n "Initial number of file extent items: "
> > +count_file_extent_items
> > +
> > +# Read the whole file in order to load extent maps and merge them.
> > +cat $SCRATCH_MNT/foo > /dev/null
> > +
> > +# Now defragment with a threshold of 128K. After this we expect to get a file
>
> > +# with 1 file extent item - the treshold is 128K but since all the extents are
>
> > +# contiguous, they should be merged into a single one of 256K.
> > +$BTRFS_UTIL_PROG filesystem defragment -t 128K $SCRATCH_MNT/foo
>
> > +echo -n "Number of file extent items after defrag with 128K treshold: "
>
> Nit: s/treshold/threshold/g
>
> > +count_file_extent_items
> > +
> > +# Read the whole file in order to load extent maps and merge them.
> > +cat $SCRATCH_MNT/foo > /dev/null
> > +
> > +# Now defragment with a threshold of 256K. After this we expect to get a file
> > +# with only 1 file extent item.
> > +$BTRFS_UTIL_PROG filesystem defragment -t 256K $SCRATCH_MNT/foo
> > +echo -n "Number of file extent items after defrag with 256K treshold: "
> > +count_file_extent_items
> > +
> > +# Check that the file has the expected data, that defrag didn't cause any data
> > +# loss or corruption.
> > +echo "File data after defrag:"
> > +_hexdump $SCRATCH_MNT/foo
> > +
>
> Nice.
>
> Nit: This can be a generic test-case.
No it can't, because:
1) Not all filesystems have a defrag functionality and with the
ability to specify a threshold;
2) We need to use dump-tree to count file extent items - both the tool
and metadata are btrfs specific.
>
> Reviewed-by: Anand Jain <anand.jain@xxxxxxxxxx>
>
> Thx, Anand
>
>
> > +status=0
> > +exit
> > diff --git a/tests/btrfs/325.out b/tests/btrfs/325.out
> > new file mode 100644
> > index 00000000..96053925
> > --- /dev/null
> > +++ b/tests/btrfs/325.out
> > @@ -0,0 +1,22 @@
> > +QA output created by 325
> > +wrote 65536/65536 bytes at offset 0
> > +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> > +wrote 65536/65536 bytes at offset 65536
> > +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> > +wrote 65536/65536 bytes at offset 131072
> > +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> > +wrote 65536/65536 bytes at offset 196608
> > +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> > +Initial number of file extent items: 4
> > +Number of file extent items after defrag with 128K treshold: 1
> > +Number of file extent items after defrag with 256K treshold: 1
> > +File data after defrag:
> > +000000 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab >................<
> > +*
> > +010000 cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd >................<
> > +*
> > +020000 ef ef ef ef ef ef ef ef ef ef ef ef ef ef ef ef >................<
> > +*
> > +030000 73 73 73 73 73 73 73 73 73 73 73 73 73 73 73 73 >ssssssssssssssss<
> > +*
> > +040000
>
