On 30/10/24 08:48, Anand Jain 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
+
With the fix applied, this test case fails when the compress option is used.
--------------
FSTYP -- btrfs
PLATFORM -- Linux/aarch64 dev2 6.12.0-rc4+ #36 SMP PREEMPT_DYNAMIC
Tue Oct 29 00:25:40 +08 2024
MKFS_OPTIONS -- /dev/sdb
MOUNT_OPTIONS -- -o compress -o context=system_u:object_r:root_t:s0
/dev/sdb /mnt/scratch
btrfs/325 1s ... - output mismatch (see
/Volumes/work/ws/fstests/results//btrfs/325.out.bad)
--- tests/btrfs/325.out 2024-10-30 08:07:48.507531048 +0800
+++ /Volumes/work/ws/fstests/results//btrfs/325.out.bad 2024-10-30
08:57:35.097186024 +0800
@@ -8,8 +8,8 @@
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
+Number of file extent items after defrag with 128K treshold: 2
+Number of file extent items after defrag with 256K treshold: 2
...
(Run 'diff -u /Volumes/work/ws/fstests/tests/btrfs/325.out
/Volumes/work/ws/fstests/results//btrfs/325.out.bad' to see the entire
diff)
--------------
One approach is to use random data, ensuring that compression remains
ineffective.
+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.
Reviewed-by: Anand Jain <anand.jain@xxxxxxxxxx>
Please ignore the rb for now.
Thanks, Anand
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
