[PATCH V2 09/11] xfs: Check for extent overflow when remapping an extent

[Chandan Babu R <chandanrlinux@gmail.com>]

This test verifies that XFS does not cause inode fork's extent count to
overflow when remapping extents from one file's inode fork to another.

Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
---
 tests/xfs/529     | 82 +++++++++++++++++++++++++++++++++++++++++++++++
 tests/xfs/529.out |  8 +++++
 tests/xfs/group   |  1 +
 3 files changed, 91 insertions(+)
 create mode 100755 tests/xfs/529
 create mode 100644 tests/xfs/529.out

diff --git a/tests/xfs/529 b/tests/xfs/529
new file mode 100755
index 00000000..47e738af
--- /dev/null
+++ b/tests/xfs/529
@@ -0,0 +1,82 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2020 Chandan Babu R.  All Rights Reserved.
+#
+# FS QA Test 529
+#
+# Verify that XFS does not cause inode fork's extent count to overflow when
+# remapping extents from one file's inode fork to another.
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+	cd /
+	rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+. ./common/reflink
+. ./common/inject
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+
+_supported_fs xfs
+_require_scratch
+_require_scratch_reflink
+_require_xfs_debug
+_require_xfs_io_command "reflink"
+_require_xfs_io_error_injection "reduce_max_iextents"
+
+echo "* Reflink remap extents"
+
+echo "Format and mount fs"
+_scratch_mkfs >> $seqres.full
+_scratch_mount >> $seqres.full
+
+bsize=$(_get_block_size $SCRATCH_MNT)
+
+srcfile=${SCRATCH_MNT}/srcfile
+dstfile=${SCRATCH_MNT}/dstfile
+
+nr_blks=40
+
+echo "Create \$srcfile having an extent of length $nr_blks blocks"
+$XFS_IO_PROG -f -c "pwrite -b $((nr_blks * bsize))  0 $((nr_blks * bsize))" \
+       -c fsync $srcfile >> $seqres.full
+
+echo "Create \$dstfile having an extent of length $nr_blks blocks"
+$XFS_IO_PROG -f -c "pwrite -b $((nr_blks * bsize))  0 $((nr_blks * bsize))" \
+       -c fsync $dstfile >> $seqres.full
+
+echo "Inject reduce_max_iextents error tag"
+_scratch_inject_error reduce_max_iextents 1
+
+echo "Reflink every other block from \$srcfile into \$dstfile"
+for i in $(seq 1 2 $((nr_blks - 1))); do
+	$XFS_IO_PROG -f -c "reflink $srcfile $((i * bsize)) $((i * bsize)) $bsize" \
+	       $dstfile >> $seqres.full 2>&1
+done
+
+echo "Verify \$dstfile's extent count"
+nextents=$($XFS_IO_PROG -c 'stat' $dstfile | grep nextents)
+nextents=${nextents##fsxattr.nextents = }
+if (( $nextents > 35 )); then
+	echo "Extent count overflow check failed: nextents = $nextents"
+	exit 1
+fi
+
+# success, all done
+status=0
+exit
diff --git a/tests/xfs/529.out b/tests/xfs/529.out
new file mode 100644
index 00000000..06b8a769
--- /dev/null
+++ b/tests/xfs/529.out
@@ -0,0 +1,8 @@
+QA output created by 529
+* Reflink remap extents
+Format and mount fs
+Create $srcfile having an extent of length 40 blocks
+Create $dstfile having an extent of length 40 blocks
+Inject reduce_max_iextents error tag
+Reflink every other block from $srcfile into $dstfile
+Verify $dstfile's extent count
diff --git a/tests/xfs/group b/tests/xfs/group
index ea892308..96e40901 100644
--- a/tests/xfs/group
+++ b/tests/xfs/group
@@ -526,6 +526,7 @@
 526 auto quick dir hardlink symlink
 527 auto quick
 528 auto quick reflink
+529 auto quick reflink
 758 auto quick rw attr realtime
 759 auto quick rw realtime
 760 auto quick rw collapse punch insert zero prealloc
-- 
2.29.2