[PATCH] xfs: test zone reset error handling

[Christoph Hellwig <hch@lst.de>]

Add a test that exercises the zone gc error handling, aka shutting
down the file system or not mounting it using the new error
injection knob and stats.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 tests/xfs/842     | 63 +++++++++++++++++++++++++++++++++++++++++++++++
 tests/xfs/842.out |  2 ++
 2 files changed, 65 insertions(+)
 create mode 100755 tests/xfs/842
 create mode 100644 tests/xfs/842.out

diff --git a/tests/xfs/842 b/tests/xfs/842
new file mode 100755
index 000000000000..8f6c13f1b19c
--- /dev/null
+++ b/tests/xfs/842
@@ -0,0 +1,63 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2026 Christoph Hellwig.
+#
+# FS QA Test No. 842
+#
+# Test that GC defragments sequentially written files.
+#
+. ./common/preamble
+_begin_fstest auto quick mount zone
+
+. ./common/filter
+. ./common/zoned
+
+_require_scratch
+_require_fs_sysfs stats/stats
+
+count_zone_resets() {
+	_get_fs_sysfs_attr $SCRATCH_DEV stats/stats | awk '/zoned/ {print $4}'
+}
+
+_scratch_mkfs >>$seqres.full 2>&1
+
+# figure out how much space we need for 3 zones worth of user data...
+blocksize=`_scratch_xfs_get_sb_field blocksize`
+rgblocks=`_scratch_xfs_get_sb_field rgextents`
+rgsize=$((3 * rgblocks * blocksize))
+echo "blocksize=${blocksize}, rgblocks=${rgblocks}, rgsize=${rgsize}" >>$seqres.full 2>&1
+
+# .. and create a file system with that size
+_scratch_mkfs_sized $rgsize >>$seqres.full 2>&1
+
+SAVED_MOUNT_OPTIONS="$MOUNT_OPTIONS"
+export MOUNT_OPTIONS="$MOUNT_OPTIONS -o errortag=zone_reset"
+_try_scratch_mount || _notrun "mount option not supported"
+_require_xfs_scratch_zoned
+
+# fill the file system and remove the data again, this should trigger zone
+# resets that will fail due to the error detection
+dd if=/dev/zero of=$SCRATCH_MNT/foo bs=1M >/dev/null 2>&1
+sync $SCRATCH_MNT
+rm $SCRATCH_MNT/foo
+sync $SCRATCH_MNT
+sleep 1
+
+touch $SCRATCH_MNT/bar 2>/dev/null && _fail "file system not shutdown"
+
+# unmount the shutdown file system
+_scratch_unmount
+
+# try mounting with error injection still enabled.  This should fail.
+_try_scratch_mount && _fail "file system mounted despite zone reset errors"
+
+# now try without the error injection
+MOUNT_OPTIONS="$SAVED_MOUNT_OPTIONS"
+_scratch_mount
+
+# all three zones should be reset on mount
+nr_resets=$(count_zone_resets)
+echo "zone resets: $nr_resets"
+
+status=0
+exit
diff --git a/tests/xfs/842.out b/tests/xfs/842.out
new file mode 100644
index 000000000000..718805b5766e
--- /dev/null
+++ b/tests/xfs/842.out
@@ -0,0 +1,2 @@
+QA output created by 842
+zone resets: 3
-- 
2.47.3