scsi/006: allow changing cache_type to fail

Some devices don't support all cache types. Allow setting the cache type
to fail with EINVAL. On success, make sure it was changed to the desired
value.

Signed-off-by: Omar Sandoval <osandov@fb.com>

diff --git a/tests/scsi/006 b/tests/scsi/006
index bccb6d69d46003338576c89af4e63467a1a1b019..f220f61e3c1e0be309dadead612c62879922498a 100755 (executable)
--- a/tests/scsi/006
+++ b/tests/scsi/006
@@ -9,7 +9,6 @@
 . tests/scsi/rc
 
 DESCRIPTION="toggle SCSI cache type"
-
 QUICK=1
 
 device_requires() {
@@ -25,15 +24,24 @@ test_device() {
                "write back"
                "write back, no read (daft)"
        )
-       local cache_type
+       local cache_type_paths
+       local cache_type_path
        local original_cache_type
+       local cache_type
 
-       original_cache_type="$(cat "${TEST_DEV_SYSFS}"/device/scsi_disk/*/cache_type)"
+       cache_type_paths=("${TEST_DEV_SYSFS}"/device/scsi_disk/*/cache_type)
+       cache_type_path="${cache_type_paths[0]}"
+       original_cache_type="$(cat "$cache_type_path")"
        for cache_type in "${cache_types[@]}"; do
-               echo "$cache_type" > "${TEST_DEV_SYSFS}"/device/scsi_disk/*/cache_type
-               cat "${TEST_DEV_SYSFS}"/device/scsi_disk/*/cache_type
+               echo "$cache_type"
+               ( echo "$cache_type" > "$cache_type_path" ) |& grep -v "Invalid argument"
+               if [[ ${PIPESTATUS[0]} -eq 0 ]]; then
+                       # If setting the cache type succeeded, it should now
+                       # contain the new cache type.
+                       grep -Fxv "$cache_type" "$cache_type_path"
+               fi
        done
-       echo "$original_cache_type" > "${TEST_DEV_SYSFS}"/device/scsi_disk/*/cache_type
+       ( echo "$original_cache_type" > "$cache_type_path" ) |& grep -v "Invalid argument"
 
        echo "Test complete"
 }