[REGRESSION,BISECTED] virtio-blk serial attribute causes guest to hang [Was: Re: [PATCH UPDATED 4/5] dm: implement REQ_FLUSH/FUA support for request-based dm]

Commit Message

Mike Snitzer Sept. 9, 2010, 8:14 p.m. UTC

None

Patch

Index: linux-2.6/block/blk-sysfs.c
===================================================================
--- linux-2.6.orig/block/blk-sysfs.c	2010-09-01 09:23:55.000000000 -0400
+++ linux-2.6/block/blk-sysfs.c	2010-09-01 17:55:50.000000000 -0400
@@ -36,6 +36,19 @@  static ssize_t queue_requests_show(struc
 	return queue_var_show(q->nr_requests, (page));
 }
 
+static ssize_t queue_requests_used_show(struct request_queue *q, char *page)
+{
+	struct request_list *rl = &q->rq;
+
+	printk("Vivek: count[sync]=%d count[async]=%d"
+		" congestion_on_thres=%d queue_congestion_off_threshold=%d\n",
+		rl->count[BLK_RW_SYNC], rl->count[BLK_RW_ASYNC],
+		queue_congestion_on_threshold(q),
+		queue_congestion_off_threshold(q));
+
+	return queue_var_show(rl->count[BLK_RW_SYNC], (page));
+}
+
 static ssize_t
 queue_requests_store(struct request_queue *q, const char *page, size_t count)
 {
@@ -266,6 +279,11 @@  static struct queue_sysfs_entry queue_re
 	.store = queue_requests_store,
 };
 
+static struct queue_sysfs_entry queue_requests_used_entry = {
+	.attr = {.name = "nr_requests_used", .mode = S_IRUGO | S_IWUSR },
+	.show = queue_requests_used_show,
+};
+
 static struct queue_sysfs_entry queue_ra_entry = {
 	.attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 	.show = queue_ra_show,
@@ -371,6 +389,7 @@  static struct queue_sysfs_entry queue_ra
 
 static struct attribute *default_attrs[] = {
 	&queue_requests_entry.attr,
+	&queue_requests_used_entry.attr,
 	&queue_ra_entry.attr,
 	&queue_max_hw_sectors_entry.attr,
 	&queue_max_sectors_entry.attr,