linux-stable.git/drivers/block/nbd.c, branch linux-2.6.28.y

nbd: fix I/O hang on disconnected nbds

2009-02-17T17:28:44+00:00

commit 4d48a542b42747c36a5937447d9c3de7c897ea50 upstream.

Fix a problem that causes I/O to a disconnected (or partially initialized)
nbd device to hang indefinitely.  To reproduce:

# ioctl NBD_SET_SIZE_BLOCKS /dev/nbd23 514048
# dd if=/dev/nbd23 of=/dev/null bs=4096 count=1

...hangs...

This can also occur when an nbd device loses its nbd-client/server
connection.  Although we clear the queue of any outstanding I/Os after the
client/server connection fails, any additional I/Os that get queued later
will hang.

This bug may also be the problem reported in this bug report:
http://bugzilla.kernel.org/show_bug.cgi?id=12277

Testing would need to be performed to determine if the two issues are the
same.

This problem was introduced by the new request handling thread code ("NBD:
allow nbd to be used locally", 3/2008), which entered into mainline around
2.6.25.

The fix, which is fairly simple, is to restore the check for lo->sock
being NULL in do_nbd_request.  This causes I/O to an uninitialized nbd to
immediately fail with an I/O error, as it did prior to the introduction of
this bug.

Signed-off-by: Paul Clements 
Reported-by: Jon Nelson 
Acked-by: Pavel Machek 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

nbd: do not allow two clients at the same time

2009-02-12T17:50:38+00:00

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 
Acked-by: Paul Clements 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

[PATCH] switch nbd

2008-10-21T11:47:53+00:00

NB: nbd_ioctl() appears to be racy; BKL is held, but doesn't really
help, AFAICS.  Left as-is for now, but it'll need fixing.

Signed-off-by: Al Viro

[PATCH] beginning of methods conversion

2008-10-21T11:47:32+00:00

To keep the size of changesets sane we split the switch by drivers;
to keep the damn thing bisectable we do the following:
	1) rename the affected methods, add ones with correct
prototypes, make (few) callers handle both.  That's this changeset.
	2) for each driver convert to new methods.  *ALL* drivers
are converted in this series.
	3) kill the old (renamed) methods.

Note that it _is_ a flagday; all in-tree drivers are converted and by the
end of this series no trace of old methods remain.  The only reason why
we do that this way is to keep the damn thing bisectable and allow per-driver
debugging if anything goes wrong.

New methods:
	open(bdev, mode)
	release(disk, mode)
	ioctl(bdev, mode, cmd, arg)		/* Called without BKL */
	compat_ioctl(bdev, mode, cmd, arg)
	locked_ioctl(bdev, mode, cmd, arg)	/* Called with BKL, legacy */

Signed-off-by: Al Viro

x86: sysfs: kill owner field from attribute

2008-10-20T15:52:42+00:00

Tejun's commit 7b595756ec1f49e0049a9e01a1298d53a7faaa15 made sysfs
attribute->owner unnecessary.  But the field was left in the structure to
ease the merge.  It's been over a year since that change and it is now
time to start killing attribute->owner along with its users - one arch at
a time!

This patch is attempt #1 to get rid of attribute->owner only for
CONFIG_X86_64 or CONFIG_X86_32 .  We will deal with other arches later on
as and when possible - avr32 will be the next since that is something I
can test.  Compile (make allyesconfig / make allmodconfig / custom config)
and boot tested.

akpm: the idea is that we put the declaration of sttribute.owner inside
`#ifndef CONFIG_X86'.  But that proved to be too ambitious for now because
new usages kept on turning up in subsystem trees.

[akpm: remove the ifdef for now]
Signed-off-by: Parag Warudkar 
Cc: Greg KH 
Cc: Ingo Molnar 
Cc: Tejun Heo 
Cc: Len Brown 
Cc: Jens Axboe 
Cc: Jean Delvare 
Cc: Roland Dreier 
Cc: David Brownell 
Cc: Alessandro Zummo 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

block: implement and use {disk|part}_to_dev()

2008-10-09T06:56:07+00:00

Implement {disk|part}_to_dev() and use them to access generic device
instead of directly dereferencing {disk|part}->dev.  To make sure no
user is left behind, rename generic devices fields to __dev.

This is in preparation of unifying partition 0 handling with other
partitions.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

nbd: fix memory leak of nbd_dev array

2008-08-20T22:40:30+00:00

We leak the memory allocated for the nbd_dev array at multiple places.
Fix them by either adding a kfree() or by rearranging code to return
before we allocate the memory.

Signed-off-by: Sven Wegener 
Cc: Paul Clements 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

2008-04-29T15:18:03+00:00

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  block: Skip I/O merges when disabled
  block: add large command support
  block: replace sizeof(rq->cmd) with BLK_MAX_CDB
  ide: use blk_rq_init() to initialize the request
  block: use blk_rq_init() to initialize the request
  block: rename and export rq_init()
  block: no need to initialize rq->cmd with blk_get_request
  block: no need to initialize rq->cmd in prepare_flush_fn hook
  block/blk-barrier.c:blk_ordered_cur_seq() mustn't be inline
  block/elevator.c:elv_rq_merge_ok() mustn't be inline
  block: make queue flags non-atomic
  block: add dma alignment and padding support to blk_rq_map_kern
  unexport blk_max_pfn
  ps3disk: Remove superfluous cast
  block: make rq_init() do a full memset()
  relay: fix splice problem

Remove duplicated unlikely() in IS_ERR()

2008-04-29T15:06:25+00:00

Some drivers have duplicated unlikely() macros.  IS_ERR() already has
unlikely() in itself.

This patch cleans up such pointless code.

Signed-off-by: Hirofumi Nakagawa 
Acked-by: David S. Miller 
Acked-by: Jeff Garzik 
Cc: Paul Clements 
Cc: Richard Purdie 
Cc: Alessandro Zummo 
Cc: David Brownell 
Cc: James Bottomley 
Cc: Michael Halcrow 
Cc: Anton Altaparmakov 
Cc: Al Viro 
Cc: Carsten Otte 
Cc: Patrick McHardy 
Cc: Paul Mundt 
Cc: Jaroslav Kysela 
Cc: Takashi Iwai 
Acked-by: Mike Frysinger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

NBD: add partition support

2008-04-29T15:06:23+00:00

Permit the use of partitions with network block devices (NBD).

A new parameter is introduced to define how many partition we want to be able
to manage per network block device.  This parameter is "max_part".

For instance, to manage 63 partitions / loop device, we will do:

   [on the server side]
# nbd-server 1234 /dev/sdb
   [on the client side]
# modprobe nbd max_part=63
# ls -l /dev/nbd*
brw-rw---- 1 root disk 43,   0 2008-03-25 11:14 /dev/nbd0
brw-rw---- 1 root disk 43,  64 2008-03-25 11:11 /dev/nbd1
brw-rw---- 1 root disk 43, 640 2008-03-25 11:11 /dev/nbd10
brw-rw---- 1 root disk 43, 704 2008-03-25 11:11 /dev/nbd11
brw-rw---- 1 root disk 43, 768 2008-03-25 11:11 /dev/nbd12
brw-rw---- 1 root disk 43, 832 2008-03-25 11:11 /dev/nbd13
brw-rw---- 1 root disk 43, 896 2008-03-25 11:11 /dev/nbd14
brw-rw---- 1 root disk 43, 960 2008-03-25 11:11 /dev/nbd15
brw-rw---- 1 root disk 43, 128 2008-03-25 11:11 /dev/nbd2
brw-rw---- 1 root disk 43, 192 2008-03-25 11:11 /dev/nbd3
brw-rw---- 1 root disk 43, 256 2008-03-25 11:11 /dev/nbd4
brw-rw---- 1 root disk 43, 320 2008-03-25 11:11 /dev/nbd5
brw-rw---- 1 root disk 43, 384 2008-03-25 11:11 /dev/nbd6
brw-rw---- 1 root disk 43, 448 2008-03-25 11:11 /dev/nbd7
brw-rw---- 1 root disk 43, 512 2008-03-25 11:11 /dev/nbd8
brw-rw---- 1 root disk 43, 576 2008-03-25 11:11 /dev/nbd9
# nbd-client localhost 1234 /dev/nbd0
Negotiation: ..size = 80418240KB
bs=1024, sz=80418240

-------NOTE, RFC: partition table is not automatically read.
The driver sets bdev->bd_invalidated to 1 to force the read of the partition
table of the device, but this is done only on an open of the device.
So we have to do a "touch /dev/nbdX" or something like that.
It can't be done from the nbd-client or nbd driver because at this
level we can't ask to read the partition table and to serve the request
at the same time (-> deadlock)

If someone has a better idea, I'm open to any suggestion.
-------NOTE, RFC

# fdisk -l /dev/nbd0

Disk /dev/nbd0: 82.3 GB, 82348277760 bytes
255 heads, 63 sectors/track, 10011 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

     Device Boot      Start         End      Blocks   Id  System
/dev/nbd0p1   *           1        9965    80043831   83  Linux
/dev/nbd0p2            9966       10011      369495    5  Extended
/dev/nbd0p5            9966       10011      369463+  82  Linux swap / Solaris

# ls -l /dev/nbd0*
brw-rw---- 1 root disk 43,   0 2008-03-25 11:16 /dev/nbd0
brw-rw---- 1 root disk 43,   1 2008-03-25 11:16 /dev/nbd0p1
brw-rw---- 1 root disk 43,   2 2008-03-25 11:16 /dev/nbd0p2
brw-rw---- 1 root disk 43,   5 2008-03-25 11:16 /dev/nbd0p5
# mount /dev/nbd0p1 /mnt
# ls /mnt
bin    dev   initrd      lost+found  opt   sbin     sys  var
boot   etc   initrd.img  media       proc  selinux  tmp  vmlinuz
cdrom  home  lib         mnt         root  srv      usr
# umount /mnt
# nbd-client -d /dev/nbd0
# ls -l /dev/nbd0*
brw-rw---- 1 root disk 43, 0 2008-03-25 11:16 /dev/nbd0
-------NOTE
On "nbd-client -d", we can do an iocl(BLKRRPART) to update partition table:
as the size of the device is 0, we don't have to serve the partition manager
request (-> no deadlock).
-------NOTE

Signed-off-by: Paul Clements 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds