generic: add buffered-io CoW test for mixed&source extents

Ensuring that copy on write in buffered mode works when the CoW
range originally covers multiple extents, mixed with reflinked,
unwritten, hole, regular and delalloc blocks.

Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

3 files changed, 128 insertions, 0 deletions

diff --git a/common/reflink b/common/reflink
index ee60398ed2..1a29e5d186 100644
--- a/common/reflink
+++ b/common/reflink
@@ -426,3 +426,54 @@ _sweave_reflink_holes_delalloc() {
 		_pwrite_byte 0x64 $((blksz * i)) $blksz $sfile.chk
 	done
 }
+
+# Create a file of interleaved holes, unwritten blocks, regular blocks, and
+# reflinked blocks
+_sweave_reflink_rainbow() {
+	local blksz=$1
+	local nr=$2
+	local sfile=$3
+	local dfile=$4
+
+	$XFS_IO_PROG -f -c "truncate $((blksz * nr))" $sfile
+	_pwrite_byte 0x00 0 $((blksz * nr)) $sfile.chk
+	_pwrite_byte 0x61 0 $((blksz * nr)) $dfile
+	seq 0 5 $((nr - 1)) | while read i; do
+		_pwrite_byte 0x61 $((blksz * i)) $blksz $sfile
+		_pwrite_byte 0x61 $((blksz * i)) $blksz $sfile.chk
+	done
+	# 0 blocks are reflinked
+	seq 0 5 $((nr - 1)) | while read i; do
+		_reflink_range $sfile $((blksz * i)) $dfile $((blksz * i)) $blksz
+		_pwrite_byte 0x61 $((blksz * i)) $blksz $sfile.chk
+	done
+	# 1 blocks are unwritten
+	seq 1 5 $((nr - 1)) | while read i; do
+		$XFS_IO_PROG -f -c "falloc $((blksz * i)) $blksz" $sfile
+		_pwrite_byte 0x00 $((blksz * i)) $blksz $sfile.chk
+	done
+	# 2 blocks are holes
+	seq 2 5 $((nr - 1)) | while read i; do
+		_pwrite_byte 0x00 $((blksz * i)) $blksz $sfile.chk
+	done
+	# 3 blocks are regular
+	seq 3 5 $((nr - 1)) | while read i; do
+		_pwrite_byte 0x71 $((blksz * i)) $blksz $sfile
+		_pwrite_byte 0x71 $((blksz * i)) $blksz $sfile.chk
+	done
+	# 4 blocks will be delalloc later
+}
+
+# For a file created with _sweave_reflink_rainbow, fill the holes with delalloc
+# extents
+_sweave_reflink_rainbow_delalloc() {
+	local blksz=$1
+	local nr=$2
+	local dfile=$3
+
+	# 4 blocks are delalloc (do later)
+	seq 4 5 $((nr - 1)) | while read i; do
+		_pwrite_byte 0x62 $((blksz * i)) $blksz $dfile
+		_pwrite_byte 0x62 $((blksz * i)) $blksz $dfile.chk
+	done
+}
diff --git a/tests/generic/667 b/tests/generic/667
new file mode 100755
index 0000000000..e9f07feb96
--- /dev/null
+++ b/tests/generic/667
@@ -0,0 +1,65 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# FS QA Test No. 667
+#
+# Ensuring that copy on write in buffered mode works when the CoW
+# range originally covers multiple extents, mixed with reflinked, unwritten,
+# hole, regular and delalloc blocks.
+#   - Create a file with the following repeating sequence of blocks:
+#     1. reflinked
+#     2. unwritten
+#     3. hole
+#     4. regular block
+#     5. delalloc
+#   - CoW across the halfway mark, starting with the unwritten extent.
+#   - Check that the files are now different where we say they're different.
+#
+. ./common/preamble
+_begin_fstest auto quick clone punch
+
+# Import common functions.
+. ./common/filter
+. ./common/reflink
+
+# real QA test starts here
+_require_scratch_reflink
+_require_scratch_delalloc
+_require_xfs_io_command "falloc"
+_require_xfs_io_command "fpunch"
+
+echo "Format and mount"
+_scratch_mkfs > $seqres.full 2>&1
+_scratch_mount >> $seqres.full 2>&1
+
+testdir=$SCRATCH_MNT/test-$seq
+mkdir $testdir
+
+echo "Create the original files"
+blksz=65536
+nr=64
+filesize=$((blksz * nr))
+_sweave_reflink_rainbow $blksz $nr $testdir/file1 $testdir/file3 >> $seqres.full
+_scratch_cycle_mount
+
+echo "Compare files"
+md5sum $testdir/file1 | _filter_scratch
+md5sum $testdir/file3 | _filter_scratch
+md5sum $testdir/file1.chk | _filter_scratch
+
+echo "CoW across the transition"
+cowoff=$((filesize / 4))
+cowsz=$((filesize / 2))
+_sweave_reflink_rainbow_delalloc $blksz $nr $testdir/file1 >> $seqres.full
+# now cow
+$XFS_IO_PROG -f -c "pwrite -S 0x63 -b $cowsz $cowoff $cowsz" $testdir/file1 >> $seqres.full
+_pwrite_byte 0x63 $cowoff $cowsz $testdir/file1.chk >> $seqres.full
+_scratch_cycle_mount
+
+echo "Compare files"
+md5sum $testdir/file1 | _filter_scratch
+md5sum $testdir/file3 | _filter_scratch
+md5sum $testdir/file1.chk | _filter_scratch
+
+# success, all done
+status=0
diff --git a/tests/generic/667.out b/tests/generic/667.out
new file mode 100644
index 0000000000..dfa8c4f934
--- /dev/null
+++ b/tests/generic/667.out
@@ -0,0 +1,12 @@
+QA output created by 667
+Format and mount
+Create the original files
+Compare files
+6366fd359371414186688a0ef6988893  SCRATCH_MNT/test-667/file1
+bdbcf02ee0aa977795a79d25fcfdccb1  SCRATCH_MNT/test-667/file3
+6366fd359371414186688a0ef6988893  SCRATCH_MNT/test-667/file1.chk
+CoW across the transition
+Compare files
+26aa3a0749b867ec58363c8539ee5471  SCRATCH_MNT/test-667/file1
+bdbcf02ee0aa977795a79d25fcfdccb1  SCRATCH_MNT/test-667/file3
+26aa3a0749b867ec58363c8539ee5471  SCRATCH_MNT/test-667/file1.chk