xfs: test xfs_healer can follow private mntns mount moves

Make sure that when xfs_healer needs to reopen a filesystem to repair
it, it can still find the filesystem even if it has been mount --move'd.
This requires a bunch of private namespace magic.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>

diff --git a/tests/xfs/667 b/tests/xfs/667
new file mode 100755 (executable)
index 0000000..1686fe8
--- /dev/null
+++ b/tests/xfs/667
@@ -0,0 +1,128 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2026 Oracle.  All Rights Reserved.
+#
+# FS QA Test No. 667
+#
+# Ensure that autonomous self healing fixes the filesystem correctly even if
+# the original mount has moved somewhere else via --move.
+#
+. ./common/preamble
+_begin_fstest auto selfhealing mount
+
+. ./common/filter
+. ./common/fuzzy
+. ./common/systemd
+
+if [ -n "$IN_MOUNTNS" ]; then
+       _mount --make-rprivate /
+       findmnt -o TARGET,PROPAGATION >> $seqres.full
+
+       _scratch_mount
+       _scratch_invoke_xfs_healer "$tmp.healer" --repair
+
+       # Move the scratch filesystem to a completely different mountpoint so that
+       # we can test if the healer can find it again.
+       new_dir=$TEST_DIR/moocow
+       mkdir -p $new_dir
+       _mount --move $SCRATCH_MNT $new_dir
+
+       df -t xfs >> $seqres.full
+
+       # Access the broken directory to trigger a repair, then poll the directory
+       # for 5 seconds to see if it gets fixed without us needing to intervene.
+       ls $new_dir/some/victimdir > /dev/null 2> $tmp.err
+       _filter_scratch < $tmp.err | _filter_test_dir
+       try=0
+       while [ $try -lt 50 ] && grep -q 'Structure needs cleaning' $tmp.err; do
+               echo "try $try saw corruption" >> $seqres.full
+               sleep 0.1
+               ls $new_dir/some/victimdir > /dev/null 2> $tmp.err
+               try=$((try + 1))
+       done
+       echo "try $try no longer saw corruption or gave up" >> $seqres.full
+       _filter_scratch < $tmp.err | _filter_test_dir
+
+       # List the dirents of /victimdir to see if it stops reporting corruption
+       ls $new_dir/some/victimdir > /dev/null 2> $tmp.err
+       try=0
+       while [ $try -lt 50 ] && grep -q 'Structure needs cleaning' $tmp.err; do
+               echo "retry $try still saw corruption" >> $seqres.full
+               sleep 0.1
+               ls $SCRATCH_MNT/some/victimdir > /dev/null 2> $tmp.err
+               try=$((try + 1))
+       done
+       echo "retry $try no longer saw corruption or gave up" >> $seqres.full
+
+       new_dir_unmount() {
+               _unmount $new_dir
+       }
+
+       # Unmount to kill the healer
+       _scratch_kill_xfs_healer new_dir_unmount
+       cat $tmp.healer >> $seqres.full
+
+       # No need to clean up, the mount ns destructor will detach the
+       # filesystems for us.
+       exit
+fi
+
+_cleanup()
+{
+       command -v _kill_fsstress &>/dev/null && _kill_fsstress
+       cd /
+       rm -r -f $tmp.*
+       if [ -n "$new_dir" ]; then
+               _unmount "$new_dir" &>/dev/null
+               rm -rf "$new_dir"
+       fi
+}
+
+_require_unshare
+_require_test
+_require_scrub
+_require_xfs_io_command "repair"       # online repair support
+_require_xfs_db_command "blocktrash"
+_require_command "$XFS_HEALER_PROG" "xfs_healer"
+_require_command "$XFS_PROPERTY_PROG" "xfs_property"
+_require_scratch
+
+_scratch_mkfs >> $seqres.full
+_scratch_mount
+
+_xfs_has_feature $SCRATCH_MNT rmapbt || \
+       _notrun "reverse mapping required to test directory auto-repair"
+_xfs_has_feature $SCRATCH_MNT parent || \
+       _notrun "parent pointers required to test directory auto-repair"
+_require_xfs_healer $SCRATCH_MNT --repair
+
+# Configure the filesystem for automatic repair of the filesystem.
+$XFS_PROPERTY_PROG $SCRATCH_MNT set autofsck=repair >> $seqres.full
+
+# Create a largeish directory
+dblksz=$(_xfs_get_dir_blocksize "$SCRATCH_MNT")
+echo testdata > $SCRATCH_MNT/a
+mkdir -p "$SCRATCH_MNT/some/victimdir"
+for ((i = 0; i < (dblksz / 255); i++)); do
+       fname="$(printf "%0255d" "$i")"
+       ln $SCRATCH_MNT/a $SCRATCH_MNT/some/victimdir/$fname
+done
+
+# Did we get at least two dir blocks?
+dirsize=$(stat -c '%s' $SCRATCH_MNT/some/victimdir)
+test "$dirsize" -gt "$dblksz" || echo "failed to create two-block directory"
+
+# Break the directory, remount filesystem
+_scratch_unmount
+_scratch_xfs_db -x \
+       -c 'path /some/victimdir' \
+       -c 'bmap' \
+       -c 'dblock 1' \
+       -c 'blocktrash -z -0 -o 0 -x 2048 -y 2048 -n 2048' >> $seqres.full
+
+# mount --move only works if mount propagation is disabled, so we have to start
+# a subshell with a separate mount namespace, disable propagation for the
+# entire directory tree, and only then can we run our tests.
+IN_MOUNTNS=1 unshare -m bash "$0"
+
+_exit 0

diff --git a/tests/xfs/667.out b/tests/xfs/667.out
new file mode 100755 (executable)
index 0000000..838c96e
--- /dev/null
+++ b/tests/xfs/667.out
@@ -0,0 +1,3 @@
+QA output created by 667
+QA output created by 667
+ls: reading directory 'TEST_DIR/moocow/some/victimdir': Structure needs cleaning