orangefs: Support readahead_readcnt parameter.

Signed-off-by: Martin Brandenburg <martin@omnibond.com>
Signed-off-by: Mike Marshall <hubcap@omnibond.com>

fs/orangefs/orangefs-sysfs.c

@@ -91,6 +91,13 @@
  * Description:
  *			Readahead cache buffer count and size.
  *
+ * What:		/sys/fs/orangefs/readahead_readcnt
+ * Date:		Jan 2017
+ * Contact:		Martin Brandenburg <martin@omnibond.com>
+ * Description:
+ *			Number of buffers (in multiples of readahead_size)
+ *			which can be read ahead for a single file at once.
+ *
  * What:		/sys/fs/orangefs/acache/...
  * Date:		Jun 2015
  * Contact:		Martin Brandenburg <martin@omnibond.com>
@@ -329,7 +336,8 @@ static ssize_t sysfs_service_op_show(struct kobject *kobj,
 		if (!(orangefs_features & ORANGEFS_FEATURE_READAHEAD) &&
 		    (!strcmp(attr->attr.name, "readahead_count") ||
 		    !strcmp(attr->attr.name, "readahead_size") ||
-		    !strcmp(attr->attr.name, "readahead_count_size"))) {
+		    !strcmp(attr->attr.name, "readahead_count_size") ||
+		    !strcmp(attr->attr.name, "readahead_readcnt"))) {
 			rc = -EINVAL;
 			goto out;
 		}
@@ -360,6 +368,11 @@ static ssize_t sysfs_service_op_show(struct kobject *kobj,
 				 "readahead_count_size"))
 			new_op->upcall.req.param.op =
 				ORANGEFS_PARAM_REQUEST_OP_READAHEAD_COUNT_SIZE;
+
+		else if (!strcmp(attr->attr.name,
+				 "readahead_readcnt"))
+			new_op->upcall.req.param.op =
+				ORANGEFS_PARAM_REQUEST_OP_READAHEAD_READCNT;
 	} else if (!strcmp(kobj->name, ACACHE_KOBJ_ID)) {
 		if (!strcmp(attr->attr.name, "timeout_msecs"))
 			new_op->upcall.req.param.op =
@@ -542,7 +555,8 @@ static ssize_t sysfs_service_op_store(struct kobject *kobj,
 		if (!(orangefs_features & ORANGEFS_FEATURE_READAHEAD) &&
 		    (!strcmp(attr->attr.name, "readahead_count") ||
 		    !strcmp(attr->attr.name, "readahead_size") ||
-		    !strcmp(attr->attr.name, "readahead_count_size"))) {
+		    !strcmp(attr->attr.name, "readahead_count_size") ||
+		    !strcmp(attr->attr.name, "readahead_readcnt"))) {
 			rc = -EINVAL;
 			goto out;
 		}
@@ -609,6 +623,15 @@ static ssize_t sysfs_service_op_store(struct kobject *kobj,
 			new_op->upcall.req.param.u.value32[0] = val1;
 			new_op->upcall.req.param.u.value32[1] = val2;
 			goto value_set;
+		} else if (!strcmp(attr->attr.name,
+				   "readahead_readcnt")) {
+			if ((val >= 0)) {
+				new_op->upcall.req.param.op =
+				ORANGEFS_PARAM_REQUEST_OP_READAHEAD_READCNT;
+			} else {
+				rc = 0;
+				goto out;
+			}
 		}
 
 	} else if (!strcmp(kobj->name, ACACHE_KOBJ_ID)) {
@@ -812,6 +835,10 @@ static struct orangefs_attribute readahead_count_size_attribute =
 	__ATTR(readahead_count_size, 0664, sysfs_service_op_show,
 	       sysfs_service_op_store);
 
+static struct orangefs_attribute readahead_readcnt_attribute =
+	__ATTR(readahead_readcnt, 0664, sysfs_service_op_show,
+	       sysfs_service_op_store);
+
 static struct orangefs_attribute perf_counter_reset_attribute =
 	__ATTR(perf_counter_reset,
 	       0664,
@@ -838,6 +865,7 @@ static struct attribute *orangefs_default_attrs[] = {
 	&readahead_count_attribute.attr,
 	&readahead_size_attribute.attr,
 	&readahead_count_size_attribute.attr,
+	&readahead_readcnt_attribute.attr,
 	&perf_counter_reset_attribute.attr,
 	&perf_history_size_attribute.attr,
 	&perf_time_interval_secs_attribute.attr,

fs/orangefs/upcall.h

@@ -182,6 +182,7 @@ enum orangefs_param_request_op {
 	ORANGEFS_PARAM_REQUEST_OP_READAHEAD_SIZE = 26,
 	ORANGEFS_PARAM_REQUEST_OP_READAHEAD_COUNT = 27,
 	ORANGEFS_PARAM_REQUEST_OP_READAHEAD_COUNT_SIZE = 28,
+	ORANGEFS_PARAM_REQUEST_OP_READAHEAD_READCNT = 29,
 };
 
 struct orangefs_param_request_s {