[PATCH v3 0/2] btrfs/076: fix failure on device with small zone_append_max_bytes

[PATCH v3 0/2] btrfs/076: fix failure on device with small zone_append_max_bytes

[Naohiro Aota]

Running btrfs/072 on a zoned null_blk device fails with a mismatch of the
number of extents. That mismatch happens because the max size of extent is
limited by not only BTRFS_MAX_UNCOMPRESSED, but also zone_append_max_bytes
on the zoned mode.

Fix the issue by calculating the expected number of extents instead of
hard-coding it in the output file.

Also, use _fixed_by_kernel_commit to rewrite the fixing commit indication
in the comment.

- v3: Use 1024s instead of "<< 10"s to represents KB or MB
- v2: Only fixed the subject lines

Naohiro Aota (2):
  btrfs/076: support smaller extent size limit
  btrfs/076: use _fixed_by_kernel_commit to tell the fixing kernel
    commit

 tests/btrfs/076     | 29 ++++++++++++++++++++++++-----
 tests/btrfs/076.out |  3 +--
 2 files changed, 25 insertions(+), 7 deletions(-)

-- 
2.42.0

[PATCH v3 1/2] btrfs/076: support smaller extent size limit

[Naohiro Aota]

Running btrfs/076 on a zoned null_blk device will fail with the following error.

  - output mismatch (see /host/results/btrfs/076.out.bad)
      --- tests/btrfs/076.out     2021-02-05 01:44:20.000000000 +0000
      +++ /host/results/btrfs/076.out.bad 2023-09-15 01:49:36.000000000 +0000
      @@ -1,3 +1,3 @@
       QA output created by 076
      -80
      -80
      +83
      +83
      ...

This is because the default value of zone_append_max_bytes is 127.5 KB
which is smaller than BTRFS_MAX_UNCOMPRESSED (128K). So, the extent size is
limited to 126976 (= ROUND_DOWN(127.5K, 4096)), which makes the number of
extents larger, and fails the test.

Instead of hard-coding the number of extents, we can calculate it using the
max extent size of an extent. It is limited by either
BTRFS_MAX_UNCOMPRESSED or zone_append_max_bytes.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 tests/btrfs/076     | 23 +++++++++++++++++++++--
 tests/btrfs/076.out |  3 +--
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/tests/btrfs/076 b/tests/btrfs/076
index 89e9672d09e2..43dbff538278 100755
--- a/tests/btrfs/076
+++ b/tests/btrfs/076
@@ -28,13 +28,28 @@ _supported_fs btrfs
 _require_test
 _require_scratch
 
+# An extent size can be up to BTRFS_MAX_UNCOMPRESSED
+max_extent_size=$(( 128 * 1024 ))
+if _scratch_btrfs_is_zoned; then
+	zone_append_max=$(cat "/sys/block/$(_short_dev $SCRATCH_DEV)/queue/zone_append_max_bytes")
+	if [[ $zone_append_max -gt 0 && $zone_append_max -lt $max_extent_size ]]; then
+		# Round down to PAGE_SIZE
+		max_extent_size=$(( $zone_append_max / 4096 * 4096 ))
+	fi
+fi
+file_size=$(( 10 * 1024 * 1024 ))
+expect=$(( (file_size + max_extent_size - 1) / max_extent_size ))
+
 _scratch_mkfs >> $seqres.full 2>&1
 _scratch_mount "-o compress=lzo"
 
 $XFS_IO_PROG -f -c "pwrite 0 10M" -c "fsync" \
 	$SCRATCH_MNT/data >> $seqres.full 2>&1
 
-_extent_count $SCRATCH_MNT/data
+res=$(_extent_count $SCRATCH_MNT/data)
+if [[ $res -ne $expect ]]; then
+	_fail "Expected $expect extents, got $res"
+fi
 
 $XFS_IO_PROG -f -c "pwrite 0 $((4096*33))" -c "fsync" \
 	$SCRATCH_MNT/data >> $seqres.full 2>&1
@@ -42,7 +57,11 @@ $XFS_IO_PROG -f -c "pwrite 0 $((4096*33))" -c "fsync" \
 $XFS_IO_PROG -f -c "pwrite 0 10M" -c "fsync" \
 	$SCRATCH_MNT/data >> $seqres.full 2>&1
 
-_extent_count $SCRATCH_MNT/data
+res=$(_extent_count $SCRATCH_MNT/data)
+if [[ $res -ne $expect ]]; then
+	_fail "Expected $expect extents, got $res"
+fi
 
+echo "Silence is golden"
 status=0
 exit
diff --git a/tests/btrfs/076.out b/tests/btrfs/076.out
index b99f7eb10a16..248e095d91af 100644
--- a/tests/btrfs/076.out
+++ b/tests/btrfs/076.out
@@ -1,3 +1,2 @@
 QA output created by 076
-80
-80
+Silence is golden
-- 
2.42.0

[PATCH v3 2/2] btrfs/076: use _fixed_by_kernel_commit to tell the fixing kernel commit

[Naohiro Aota]

The fix commit is written in the comment without a commit hash. Use
_fixed_by_kernel_commit command to describe it.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 tests/btrfs/076 | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tests/btrfs/076 b/tests/btrfs/076
index 43dbff538278..894a1ac7fa5d 100755
--- a/tests/btrfs/076
+++ b/tests/btrfs/076
@@ -5,10 +5,8 @@
 # FS QA Test No. btrfs/076
 #
 # Regression test for btrfs incorrect inode ratio detection.
-# This was fixed in the following linux kernel patch:
-#
-#     Btrfs: fix incorrect compression ratio detection
 #
+
 . ./common/preamble
 _begin_fstest auto quick compress
 
@@ -27,6 +25,8 @@ _cleanup()
 _supported_fs btrfs
 _require_test
 _require_scratch
+_fixed_by_kernel_commit 4bcbb3325513 \
+	"Btrfs: fix incorrect compression ratio detection"
 
 # An extent size can be up to BTRFS_MAX_UNCOMPRESSED
 max_extent_size=$(( 128 * 1024 ))
-- 
2.42.0