[PATCH V6 11/13] 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.

Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
---
 tests/xfs/535     | 81 +++++++++++++++++++++++++++++++++++++++++++++++
 tests/xfs/535.out |  8 +++++
 tests/xfs/group   |  1 +
 3 files changed, 90 insertions(+)
 create mode 100755 tests/xfs/535
 create mode 100644 tests/xfs/535.out

diff --git a/tests/xfs/535 b/tests/xfs/535
new file mode 100755
index 00000000..98209e06
--- /dev/null
+++ b/tests/xfs/535
@@ -0,0 +1,81 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2021 Chandan Babu R.  All Rights Reserved.
+#
+# FS QA Test 535
+#
+# 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=15
+
+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
+	_reflink_range $srcfile $((i * bsize)) $dstfile $((i * bsize)) $bsize \
+		       >> $seqres.full 2>&1
+done
+
+echo "Verify \$dstfile's extent count"
+nextents=$(_xfs_get_fsxattr nextents $dstfile)
+if (( $nextents > 10 )); then
+	echo "Extent count overflow check failed: nextents = $nextents"
+	exit 1
+fi
+
+# success, all done
+status=0
+exit
diff --git a/tests/xfs/535.out b/tests/xfs/535.out
new file mode 100644
index 00000000..cfe50f45
--- /dev/null
+++ b/tests/xfs/535.out
@@ -0,0 +1,8 @@
+QA output created by 535
+* Reflink remap extents
+Format and mount fs
+Create $srcfile having an extent of length 15 blocks
+Create $dstfile having an extent of length 15 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 b4f0c777..aed06494 100644
--- a/tests/xfs/group
+++ b/tests/xfs/group
@@ -532,3 +532,4 @@
 532 auto quick dir hardlink symlink
 533 auto quick
 534 auto quick reflink
+535 auto quick reflink
-- 
2.29.2