diff options
author | Pavel Machek <pavel@suse.cz> | 2009-01-15 16:51:03 -0500 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-15 19:39:38 -0500 |
commit | c91192d66d6cea7878b8542c9d9f1873971aba92 (patch) | |
tree | 954adf09a2d6f4028aa8c3a842aa07235e3d4be5 /drivers/block | |
parent | 1bcbf31337391a2f54ef6c1e8871c2de5944a7dc (diff) |
nbd: do not allow two clients at the same time
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>
Diffstat (limited to 'drivers/block')
-rw-r--r-- | drivers/block/nbd.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 7bcc1d8bc967..34f80fa6fed1 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c | |||
@@ -406,6 +406,7 @@ static int nbd_do_it(struct nbd_device *lo) | |||
406 | ret = sysfs_create_file(&disk_to_dev(lo->disk)->kobj, &pid_attr.attr); | 406 | ret = sysfs_create_file(&disk_to_dev(lo->disk)->kobj, &pid_attr.attr); |
407 | if (ret) { | 407 | if (ret) { |
408 | printk(KERN_ERR "nbd: sysfs_create_file failed!"); | 408 | printk(KERN_ERR "nbd: sysfs_create_file failed!"); |
409 | lo->pid = 0; | ||
409 | return ret; | 410 | return ret; |
410 | } | 411 | } |
411 | 412 | ||
@@ -413,6 +414,7 @@ static int nbd_do_it(struct nbd_device *lo) | |||
413 | nbd_end_request(req); | 414 | nbd_end_request(req); |
414 | 415 | ||
415 | sysfs_remove_file(&disk_to_dev(lo->disk)->kobj, &pid_attr.attr); | 416 | sysfs_remove_file(&disk_to_dev(lo->disk)->kobj, &pid_attr.attr); |
417 | lo->pid = 0; | ||
416 | return 0; | 418 | return 0; |
417 | } | 419 | } |
418 | 420 | ||
@@ -648,6 +650,8 @@ static int nbd_ioctl(struct block_device *bdev, fmode_t mode, | |||
648 | set_capacity(lo->disk, lo->bytesize >> 9); | 650 | set_capacity(lo->disk, lo->bytesize >> 9); |
649 | return 0; | 651 | return 0; |
650 | case NBD_DO_IT: | 652 | case NBD_DO_IT: |
653 | if (lo->pid) | ||
654 | return -EBUSY; | ||
651 | if (!lo->file) | 655 | if (!lo->file) |
652 | return -EINVAL; | 656 | return -EINVAL; |
653 | thread = kthread_create(nbd_thread, lo, lo->disk->disk_name); | 657 | thread = kthread_create(nbd_thread, lo, lo->disk->disk_name); |