From e9c71689c06e6560820c18a699ea8d4850b36888 Mon Sep 17 00:00:00 2001
From: Pavel Machek <pavel@suse.cz>
Date: Thu, 15 Jan 2009 13:51:03 -0800
Subject: [PATCH] --- yaml --- r: 129676 b: refs/heads/master c:
 c91192d66d6cea7878b8542c9d9f1873971aba92 h: refs/heads/master v: v3

---
 [refs]                    | 2 +-
 trunk/drivers/block/nbd.c | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index cacc4b292c21..761896070452 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 1bcbf31337391a2f54ef6c1e8871c2de5944a7dc
+refs/heads/master: c91192d66d6cea7878b8542c9d9f1873971aba92
diff --git a/trunk/drivers/block/nbd.c b/trunk/drivers/block/nbd.c
index 7bcc1d8bc967..34f80fa6fed1 100644
--- a/trunk/drivers/block/nbd.c
+++ b/trunk/drivers/block/nbd.c
@@ -406,6 +406,7 @@ static int nbd_do_it(struct nbd_device *lo)
 	ret = sysfs_create_file(&disk_to_dev(lo->disk)->kobj, &pid_attr.attr);
 	if (ret) {
 		printk(KERN_ERR "nbd: sysfs_create_file failed!");
+		lo->pid = 0;
 		return ret;
 	}
 
@@ -413,6 +414,7 @@ static int nbd_do_it(struct nbd_device *lo)
 		nbd_end_request(req);
 
 	sysfs_remove_file(&disk_to_dev(lo->disk)->kobj, &pid_attr.attr);
+	lo->pid = 0;
 	return 0;
 }
 
@@ -648,6 +650,8 @@ static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
 		set_capacity(lo->disk, lo->bytesize >> 9);
 		return 0;
 	case NBD_DO_IT:
+		if (lo->pid)
+			return -EBUSY;
 		if (!lo->file)
 			return -EINVAL;
 		thread = kthread_create(nbd_thread, lo, lo->disk->disk_name);