@@ -832,6 +832,54 @@ static int btrfs_strmatch(const char *given, const char *golden)
return -EINVAL;
}
+static const char* const btrfs_read_policy_name[] = { "pid" };
+
+static ssize_t btrfs_read_policy_show(struct kobject *kobj,
+ struct kobj_attribute *a, char *buf)
+{
+ int i;
+ ssize_t ret = 0;
+ struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
+
+ for (i = 0; i < BTRFS_NR_READ_POLICY; i++) {
+ if (fs_devices->read_policy == i)
+ ret += snprintf(buf + ret, PAGE_SIZE - ret, "%s[%s]",
+ (ret == 0 ? "" : " "),
+ btrfs_read_policy_name[i]);
+ else
+ ret += snprintf(buf + ret, PAGE_SIZE - ret, "%s%s",
+ (ret == 0 ? "" : " "),
+ btrfs_read_policy_name[i]);
+ }
+
+ ret += snprintf(buf + ret, PAGE_SIZE - ret, "\n");
+
+ return ret;
+}
+
+static ssize_t btrfs_read_policy_store(struct kobject *kobj,
+ struct kobj_attribute *a,
+ const char *buf, size_t len)
+{
+ int i;
+ struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
+
+ for (i = 0; i < BTRFS_NR_READ_POLICY; i++) {
+ if (btrfs_strmatch(buf, btrfs_read_policy_name[i]) == 0) {
+ if (i != fs_devices->read_policy) {
+ fs_devices->read_policy = i;
+ btrfs_info(fs_devices->fs_info,
+ "read policy set to '%s'",
+ btrfs_read_policy_name[i]);
+ }
+ return len;
+ }
+ }
+
+ return -EINVAL;
+}
+BTRFS_ATTR_RW(, read_policy, btrfs_read_policy_show, btrfs_read_policy_store);
+
static const struct attribute *btrfs_attrs[] = {
BTRFS_ATTR_PTR(, label),
BTRFS_ATTR_PTR(, nodesize),
@@ -840,6 +888,7 @@ static int btrfs_strmatch(const char *given, const char *golden)
BTRFS_ATTR_PTR(, quota_override),
BTRFS_ATTR_PTR(, metadata_uuid),
BTRFS_ATTR_PTR(, checksum),
+ BTRFS_ATTR_PTR(, read_policy),
NULL,
};