scripts: fix Windows test dm/loopback cleanup

The Windows integration test scripts tore down their device-mapper
snapshot and loop devices with 'dmsetup remove_all -f' and 'losetup
-D'. Both operate on every such device on the host, not just the ones
the script created.

On a host whose root filesystem is device-mapper backed (for example an
LVM root), 'dmsetup remove_all -f' replaces the in-use root device's
table with an error target. The host is wedged until reboot.  This is
harmless in CI, which runs in a disposable VM, but destroys a developer
machine.

It turns out windows-snapshot-base is not used at all. Drop it.

Signed-off-by: Wei Liu <liuwe@microsoft.com>
Assisted-by: Copilot:Opus-4.8

scripts/run_integration_tests_windows_aarch64.sh

@@ -31,13 +31,35 @@ if [[ ! -f ${WIN_IMAGE_FILE} || ! -f ${OVMF_FW} ]]; then
     exit 1
 fi
 
+# Remove every device-mapper device this Windows test suite may have created
+# (the base plus any per-test snapshot a crashed or timed-out test left
+# behind). Snapshots reference the base as their origin and must be removed
+# first, so retry a few times to tolerate ordering. Only 'windows-*' devices
+# are touched, never any other device-mapper device on the host.
+cleanup_windows_dm() {
+    for _ in 1 2 3; do
+        local devs
+        devs=$(dmsetup ls 2>/dev/null | awk '{print $1}' | grep '^windows-' || true)
+        [ -z "$devs" ] && break
+        for dev in $devs; do
+            dmsetup remove "$dev" 2>/dev/null || true
+        done
+    done
+}
+
+# Clear anything a previous crashed or killed run left behind so the dmsetup
+# create below does not fail on a stale device, then detach any stale loop
+# devices still backing the image.
+cleanup_windows_dm
+losetup -j "${WIN_IMAGE_FILE}" | cut -d : -f 1 | while read -r stale; do
+    losetup -d "$stale" 2>/dev/null || true
+done
+
 # Use device mapper to create a snapshot of the Windows image
 img_blk_size=$(du -b -B 512 "${WIN_IMAGE_FILE}" | awk '{print $1;}')
 loop_device=$(losetup --find --show --read-only "${WIN_IMAGE_FILE}")
 dmsetup create windows-base --table "0 $img_blk_size linear $loop_device 0"
 dmsetup mknodes
-dmsetup create windows-snapshot-base --table "0 $img_blk_size snapshot-origin /dev/mapper/windows-base"
-dmsetup mknodes
 
 # Common configuration for every test run
 export RUST_BACKTRACE=1
@@ -50,7 +72,9 @@ cargo build --all --release --target "$BUILD_TARGET"
 time cargo nextest run -p cloud-hypervisor --retries 3 --no-tests=pass "windows::$test_filter" --target "$BUILD_TARGET" -- ${test_binary_args[*]}
 RES=$?
 
-dmsetup remove_all -f
-losetup -D
+# Tear down the base and any per-test snapshot devices left over from a crash,
+# then detach this run's loop device.
+cleanup_windows_dm
+losetup -d "$loop_device" 2>/dev/null || true
 
 exit $RES

scripts/run_integration_tests_windows_x86_64.sh

@@ -36,13 +36,35 @@ if [[ ! -f ${WIN_IMAGE_FILE} || ! -f ${OVMF_FW} ]]; then
     exit 1
 fi
 
+# Remove every device-mapper device this Windows test suite may have created
+# (the base plus any per-test snapshot a crashed or timed-out test left
+# behind). Snapshots reference the base as their origin and must be removed
+# first, so retry a few times to tolerate ordering. Only 'windows-*' devices
+# are touched, never any other device-mapper device on the host.
+cleanup_windows_dm() {
+    for _ in 1 2 3; do
+        local devs
+        devs=$(dmsetup ls 2>/dev/null | awk '{print $1}' | grep '^windows-' || true)
+        [ -z "$devs" ] && break
+        for dev in $devs; do
+            dmsetup remove "$dev" 2>/dev/null || true
+        done
+    done
+}
+
+# Clear anything a previous crashed or killed run left behind so the dmsetup
+# create below does not fail on a stale device, then detach any stale loop
+# devices still backing the image.
+cleanup_windows_dm
+losetup -j ${WIN_IMAGE_FILE} | cut -d : -f 1 | while read -r stale; do
+    losetup -d "$stale" 2>/dev/null || true
+done
+
 # Use device mapper to create a snapshot of the Windows image
 img_blk_size=$(du -b -B 512 ${WIN_IMAGE_FILE} | awk '{print $1;}')
 loop_device=$(losetup --find --show --read-only ${WIN_IMAGE_FILE})
 dmsetup create windows-base --table "0 $img_blk_size linear $loop_device 0"
 dmsetup mknodes
-dmsetup create windows-snapshot-base --table "0 $img_blk_size snapshot-origin /dev/mapper/windows-base"
-dmsetup mknodes
 
 cargo build --features mshv --all --release --target "$BUILD_TARGET"
 
@@ -55,7 +77,9 @@ export RUSTFLAGS="$RUSTFLAGS"
 time cargo nextest run -p cloud-hypervisor --retries 3 --no-tests=pass $test_features "windows::$test_filter" --target "$BUILD_TARGET" -- ${test_binary_args[*]}
 RES=$?
 
-dmsetup remove_all -f
-losetup -D
+# Tear down the base and any per-test snapshot devices left over from a crash,
+# then detach this run's loop device.
+cleanup_windows_dm
+losetup -d "$loop_device" 2>/dev/null || true
 
 exit $RES