+/*
+ * Attempt to mount a filesystem safely, while handling certain filesytem-
+ * specific options
+ */
+static int try_mount(const char *device_path, const char *mount_path,
+ const char *fstype, unsigned long flags,
+ bool have_snapshot)
+{
+ const char *fs, *safe_opts;
+ int rc;
+
+ /* Mount ext3 as ext4 instead so 'norecovery' can be used */
+ if (strncmp(fstype, "ext3", strlen("ext3")) == 0) {
+ pb_debug("Mounting ext3 filesystem as ext4\n");
+ fs = "ext4";
+ } else
+ fs = fstype;
+
+ if (strncmp(fs, "xfs", strlen("xfs")) == 0 ||
+ strncmp(fs, "ext4", strlen("ext4")) == 0)
+ safe_opts = "norecovery";
+ else
+ safe_opts = NULL;
+
+ errno = 0;
+ /* If no snapshot is available don't attempt recovery */
+ if (!have_snapshot)
+ return mount(device_path, mount_path, fs, flags, safe_opts);
+
+ rc = mount(device_path, mount_path, fs, flags, NULL);
+
+ if (!rc)
+ return rc;
+
+ /* Mounting failed; some filesystems will fail to mount if a recovery
+ * journal exists (eg. cross-endian XFS), so try again with norecovery
+ * where that option is available.
+ * If mounting read-write just return the error as norecovery is not a
+ * valid option */
+ if ((flags & MS_RDONLY) != MS_RDONLY || !safe_opts)
+ return rc;
+
+ errno = 0;
+ return mount(device_path, mount_path, fs, flags, safe_opts);
+}
+