[PATCH V4 10/11] xfs: Check for extent overflow when swapping extents

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

This test verifies that XFS does not cause inode fork's extent count to
overflow when swapping forks across two files.

Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
---
 tests/xfs/530     | 109 ++++++++++++++++++++++++++++++++++++++++++++++
 tests/xfs/530.out |  13 ++++++
 tests/xfs/group   |   1 +
 3 files changed, 123 insertions(+)
 create mode 100755 tests/xfs/530
 create mode 100644 tests/xfs/530.out

diff --git a/tests/xfs/530 b/tests/xfs/530
new file mode 100755
index 00000000..0986d8bf
--- /dev/null
+++ b/tests/xfs/530
@@ -0,0 +1,109 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2020 Chandan Babu R.  All Rights Reserved.
+#
+# FS QA Test 530
+#
+# Verify that XFS does not cause inode fork's extent count to overflow when
+# swapping forks between files
+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/inject
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+
+_supported_fs xfs
+_require_scratch
+_require_xfs_debug
+_require_xfs_scratch_rmapbt
+_require_xfs_io_command "fcollapse"
+_require_xfs_io_command "swapext"
+_require_xfs_io_error_injection "reduce_max_iextents"
+
+echo "* Swap extent forks"
+
+echo "Format and mount fs"
+_scratch_mkfs >> $seqres.full
+_scratch_mount >> $seqres.full
+
+bsize=$(_get_block_size $SCRATCH_MNT)
+
+srcfile=${SCRATCH_MNT}/srcfile
+donorfile=${SCRATCH_MNT}/donorfile
+
+echo "Create \$donorfile having an extent of length 67 blocks"
+$XFS_IO_PROG -f -s -c "pwrite -b $((17 * bsize)) 0 $((17 * bsize))" $donorfile \
+       >> $seqres.full
+
+# After the for loop the donor file will have the following extent layout
+# | 0-4 | 5 | 6 | 7 | 8 | 9 | 10 |
+echo "Fragment \$donorfile"
+for i in $(seq 5 10); do
+	start_offset=$((i * bsize))
+	$XFS_IO_PROG -f -c "fcollapse $start_offset $bsize" $donorfile >> $seqres.full
+done
+
+echo "Create \$srcfile having an extent of length 18 blocks"
+$XFS_IO_PROG -f -s -c "pwrite -b $((18 * bsize)) 0 $((18 * bsize))" $srcfile \
+       >> $seqres.full
+
+echo "Fragment \$srcfile"
+# After the for loop the src file will have the following extent layout
+# | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7-10 |
+for i in $(seq 1 7); do
+	start_offset=$((i * bsize))
+	$XFS_IO_PROG -f -c "fcollapse $start_offset $bsize" $srcfile >> $seqres.full
+done
+
+echo "Collect \$donorfile's extent count"
+donor_nr_exts=$($XFS_IO_PROG -c 'stat' $donorfile | grep nextents)
+donor_nr_exts=${donor_nr_exts##fsxattr.nextents = }
+
+echo "Collect \$srcfile's extent count"
+src_nr_exts=$($XFS_IO_PROG -c 'stat' $srcfile | grep nextents)
+src_nr_exts=${src_nr_exts##fsxattr.nextents = }
+
+echo "Inject reduce_max_iextents error tag"
+_scratch_inject_error reduce_max_iextents 1
+
+echo "Swap \$srcfile's and \$donorfile's extent forks"
+$XFS_IO_PROG -f -c "swapext $donorfile" $srcfile >> $seqres.full 2>&1
+
+echo "Check for \$donorfile's extent count overflow"
+nextents=$($XFS_IO_PROG -c 'stat' $donorfile | grep nextents)
+nextents=${nextents##fsxattr.nextents = }
+
+if (( $nextents == $src_nr_exts )); then
+	echo "\$donorfile: Extent count overflow check failed"
+fi
+
+echo "Check for \$srcfile's extent count overflow"
+nextents=$($XFS_IO_PROG -c 'stat' $srcfile | grep nextents)
+nextents=${nextents##fsxattr.nextents = }
+
+if (( $nextents == $donor_nr_exts )); then
+	echo "\$srcfile: Extent count overflow check failed"
+fi
+
+# success, all done
+status=0
+exit
diff --git a/tests/xfs/530.out b/tests/xfs/530.out
new file mode 100644
index 00000000..9f55608b
--- /dev/null
+++ b/tests/xfs/530.out
@@ -0,0 +1,13 @@
+QA output created by 530
+* Swap extent forks
+Format and mount fs
+Create $donorfile having an extent of length 67 blocks
+Fragment $donorfile
+Create $srcfile having an extent of length 18 blocks
+Fragment $srcfile
+Collect $donorfile's extent count
+Collect $srcfile's extent count
+Inject reduce_max_iextents error tag
+Swap $srcfile's and $donorfile's extent forks
+Check for $donorfile's extent count overflow
+Check for $srcfile's extent count overflow
diff --git a/tests/xfs/group b/tests/xfs/group
index bc3958b3..81a15582 100644
--- a/tests/xfs/group
+++ b/tests/xfs/group
@@ -527,3 +527,4 @@
 527 auto quick
 528 auto quick reflink
 529 auto quick reflink
+530 auto quick
-- 
2.29.2