lkml.org 
[lkml]   [2009]   [Feb]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[patch 52/53] nbd: do not allow two clients at the same time
2.6.28-stable review patch.  If anyone has any objections, please let us know.
------------------

From: Pavel Machek <pavel@suse.cz>

commit c91192d66d6cea7878b8542c9d9f1873971aba92 upstream.

Two nbd-clients at same time are bad idea, and cause WARN_ON from nbd in
2.6.28-rc7 from sysfs_add_one. This simply prevents that from happening.

To reproduce:

cat /dev/zero | head -c 10000000 > /tmp/delme.fstest.fs
nbd-server 9100 -l /anyone.can.connect > /tmp/delme.fstest.fs &
sleep 1
nbd-client localhost 9100 /dev/nd0 &
nbd-client localhost 9100 /dev/nd0 &

Signed-off-by: Pavel Machek <pavel@suse.cz>
Acked-by: Paul Clements <paul.clements@steeleye.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/block/nbd.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -406,6 +406,7 @@ static int nbd_do_it(struct nbd_device *
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 *
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
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);


\
 
 \ /
  Last update: 2009-02-10 20:25    [W:0.223 / U:0.792 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site