[PATCH 07/11] xfs: Check for extent overflow when writing to unwritten extent

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

This test verifies that XFS does not cause inode fork's extent count to
overflow when writing to an unwritten extent.

Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
---
 tests/xfs/527     | 125 ++++++++++++++++++++++++++++++++++++++++++++++
 tests/xfs/527.out |  13 +++++
 tests/xfs/group   |   1 +
 3 files changed, 139 insertions(+)
 create mode 100755 tests/xfs/527
 create mode 100644 tests/xfs/527.out

diff --git a/tests/xfs/527 b/tests/xfs/527
new file mode 100755
index 00000000..f040aee4
--- /dev/null
+++ b/tests/xfs/527
@@ -0,0 +1,125 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2020 Chandan Babu R.  All Rights Reserved.
+#
+# FS QA Test 527
+#
+# Verify that XFS does not cause inode fork's extent count to overflow when
+# writing to an unwritten extent.
+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_io_command "falloc"
+_require_xfs_io_error_injection "reduce_max_iextents"
+
+buffered_write_to_unwritten_extent()
+{
+	echo "* Buffered write to unwritten extent"
+
+	echo "Format and mount fs"
+	_scratch_mkfs_sized $((1024 * 1024 * 1024)) >> $seqres.full
+	_scratch_mount >> $seqres.full
+
+	bsize=$(_get_block_size $SCRATCH_MNT)
+
+	testfile=${SCRATCH_MNT}/testfile
+
+	nr_blks=15
+
+	echo "Fallocate $nr_blks blocks"
+	xfs_io -f -c "falloc 0 $((nr_blks * bsize))" $testfile >> $seqres.full
+
+	echo "Inject reduce_max_iextents error tag"
+	xfs_io -x -c "inject reduce_max_iextents" $SCRATCH_MNT
+
+	echo "Buffered write to every other block of fallocated space"
+	for i in $(seq 1 2 $((nr_blks - 1))); do
+		xfs_io -f -c "pwrite $((i * bsize)) $bsize" -c fsync $testfile \
+		       >> $seqres.full 2>&1
+		[[ $? != 0 ]] && break
+	done
+
+	testino=$(stat -c "%i" $testfile)
+
+	_scratch_unmount >> $seqres.full
+
+	echo "Verify \$testfile's extent count"
+
+	nextents=$(_scratch_get_iext_count $testino data || \
+			_fail "Unable to obtain inode fork's extent count")
+	if (( $nextents > 10 )); then
+		echo "Extent count overflow check failed: nextents = $nextents"
+	fi
+}
+
+direct_write_to_unwritten_extent()
+{
+	echo "* Direct I/O write to unwritten extent"
+
+	echo "Format and mount fs"
+	_scratch_mkfs_sized $((1024 * 1024 * 1024)) >> $seqres.full
+	_scratch_mount >> $seqres.full
+
+	bsize=$(_get_block_size $SCRATCH_MNT)
+
+	testfile=${SCRATCH_MNT}/testfile
+
+	nr_blks=15
+
+	echo "Fallocate $nr_blks blocks"
+	xfs_io -f -c "falloc 0 $((nr_blks * bsize))" $testfile >> $seqres.full
+
+	echo "Inject reduce_max_iextents error tag"
+	xfs_io -x -c "inject reduce_max_iextents" $SCRATCH_MNT
+
+	echo "Direct I/O write to every other block of fallocated space"
+	for i in $(seq 1 2 $((nr_blks - 1))); do
+		xfs_io -f -d -c "pwrite $((i * bsize)) $bsize" $testfile \
+		       >> $seqres.full 2>&1
+		[[ $? != 0 ]] && break
+	done
+
+	testino=$(stat -c "%i" $testfile)
+
+	_scratch_unmount >> $seqres.full
+
+	echo "Verify \$testfile's extent count"
+
+	nextents=$(_scratch_get_iext_count $testino data || \
+			_fail "Unable to obtain inode fork's extent count")
+	if (( $nextents > 10 )); then
+		echo "Extent count overflow check failed: nextents = $nextents"
+	fi
+}
+
+buffered_write_to_unwritten_extent
+direct_write_to_unwritten_extent
+
+# success, all done
+status=0
+exit
diff --git a/tests/xfs/527.out b/tests/xfs/527.out
new file mode 100644
index 00000000..6aa5e9ed
--- /dev/null
+++ b/tests/xfs/527.out
@@ -0,0 +1,13 @@
+QA output created by 527
+* Buffered write to unwritten extent
+Format and mount fs
+Fallocate 15 blocks
+Inject reduce_max_iextents error tag
+Buffered write to every other block of fallocated space
+Verify $testfile's extent count
+* Direct I/O write to unwritten extent
+Format and mount fs
+Fallocate 15 blocks
+Inject reduce_max_iextents error tag
+Direct I/O write to every other block of fallocated space
+Verify $testfile's extent count
diff --git a/tests/xfs/group b/tests/xfs/group
index d089797b..627813fe 100644
--- a/tests/xfs/group
+++ b/tests/xfs/group
@@ -524,3 +524,4 @@
 524 auto quick punch zero insert collapse
 525 auto quick attr
 526 auto quick dir hardlink symlink
+527 auto quick
-- 
2.28.0