kernel/git/stable/linux.git/drivers/block/nbd.c, branch linux-2.6.33.y

nbd: limit module parameters to a sane value

2011-06-23T22:28:39+00:00

commit 3b2710824e00d238554c13b5add347e6c701ab1a upstream. The 'max_part' parameter controls the number of maximum partition a nbd device can have. However if a user specifies very large value it would exceed the limitation of device minor number and can cause a kernel oops (or, at least, produce invalid device nodes in some cases). In addition, specifying large 'nbds_max' value causes same problem for the same reason. On my desktop, following command results to the kernel bug: $ sudo modprobe nbd max_part=100000 kernel BUG at /media/Linux_Data/project/linux/fs/sysfs/group.c:65! invalid opcode: 0000 [#1] SMP last sysfs file: /sys/devices/virtual/block/nbd4/range CPU 1 Modules linked in: nbd(+) bridge stp llc kvm_intel kvm asus_atk0110 sg sr_mod cdrom Pid: 2522, comm: modprobe Tainted: G W 2.6.39-leonard+ #159 System manufacturer System Product Name/P5G41TD-M PRO RIP: 0010:[] [] internal_create_group+0x2f/0x166 RSP: 0018:ffff8801009f1de8 EFLAGS: 00010246 RAX: 00000000ffffffef RBX: ffff880103920478 RCX: 00000000000a7bd3 RDX: ffffffff81a2dbe0 RSI: 0000000000000000 RDI: ffff880103920478 RBP: ffff8801009f1e38 R08: ffff880103920468 R09: ffff880103920478 R10: ffff8801009f1de8 R11: ffff88011eccbb68 R12: ffffffff81a2dbe0 R13: ffff880103920468 R14: 0000000000000000 R15: ffff880103920400 FS: 00007f3c49de9700(0000) GS:ffff88011f800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00007f3b7fe7c000 CR3: 00000000cd58d000 CR4: 00000000000406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process modprobe (pid: 2522, threadinfo ffff8801009f0000, task ffff8801009a93a0) Stack: ffff8801009f1e58 ffffffff812e8f6e ffff8801009f1e58 ffffffff812e7a80 ffff880000000010 ffff880103920400 ffff8801002fd0c0 ffff880103920468 0000000000000011 ffff880103920400 ffff8801009f1e48 ffffffff8115ab6a Call Trace: [] ? device_add+0x4f1/0x5e4 [] ? dev_set_name+0x41/0x43 [] sysfs_create_group+0x13/0x15 [] blk_trace_init_sysfs+0x14/0x16 [] blk_register_queue+0x4c/0xfd [] add_disk+0xe4/0x29c [] nbd_init+0x2ab/0x30d [nbd] [] ? 0xffffffffa007dfff [] do_one_initcall+0x7f/0x13e [] sys_init_module+0xa1/0x1e3 [] system_call_fastpath+0x16/0x1b Code: 41 57 41 56 41 55 41 54 53 48 83 ec 28 0f 1f 44 00 00 48 89 fb 41 89 f6 49 89 d4 48 85 ff 74 0b 85 f6 75 0b 48 83 7f 30 00 75 14 <0f> 0b eb fe b9 ea ff ff ff 48 83 7f 30 00 0f 84 09 01 00 00 49 RIP [] internal_create_group+0x2f/0x166 RSP ---[ end trace 753285ffbf72c57c ]--- Signed-off-by: Namhyung Kim Cc: Laurent Vivier Cc: Paul Clements Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

const: make block_device_operations const

2009-09-22T14:17:25+00:00

Signed-off-by: Alexey Dobriyan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

block: implement and enforce request peek/start/fetch

2009-05-11T07:52:18+00:00

Till now block layer allowed two separate modes of request execution. A request is always acquired from the request queue via elv_next_request(). After that, drivers are free to either dequeue it or process it without dequeueing. Dequeue allows elv_next_request() to return the next request so that multiple requests can be in flight. Executing requests without dequeueing has its merits mostly in allowing drivers for simpler devices which can't do sg to deal with segments only without considering request boundary. However, the benefit this brings is dubious and declining while the cost of the API ambiguity is increasing. Segment based drivers are usually for very old or limited devices and as converting to dequeueing model isn't difficult, it doesn't justify the API overhead it puts on block layer and its more modern users. Previous patches converted all block low level drivers to dequeueing model. This patch completes the API transition by... * renaming elv_next_request() to blk_peek_request() * renaming blkdev_dequeue_request() to blk_start_request() * adding blk_fetch_request() which is combination of peek and start * disallowing completion of queued (not started) requests * applying new API to all LLDs Renamings are for consistency and to break out of tree code so that it's apparent that out of tree drivers need updating. [ Impact: block request issue API cleanup, no functional change ] Signed-off-by: Tejun Heo Cc: Rusty Russell Cc: James Bottomley Cc: Mike Miller Cc: unsik Kim Cc: Paul Clements Cc: Tim Waugh Cc: Geert Uytterhoeven Cc: David S. Miller Cc: Laurent Vivier Cc: Jeff Garzik Cc: Jeremy Fitzhardinge Cc: Grant Likely Cc: Adrian McMenamin Cc: Stephen Rothwell Cc: Bartlomiej Zolnierkiewicz Cc: Borislav Petkov Cc: Sergei Shtylyov Cc: Alex Dubov Cc: Pierre Ossman Cc: David Woodhouse Cc: Markus Lidel Cc: Stefan Weinhuber Cc: Martin Schwidefsky Cc: Pete Zaitcev Cc: FUJITA Tomonori Signed-off-by: Jens Axboe

block: blk_rq_[cur_]_{sectors|bytes}() usage cleanup

2009-05-11T07:50:55+00:00

With the previous changes, the followings are now guaranteed for all requests in any valid state. * blk_rq_sectors() == blk_rq_bytes() >> 9 * blk_rq_cur_sectors() == blk_rq_cur_bytes() >> 9 Clean up accessor usages. Notable changes are * nbd,i2o_block: end_all used instead of explicit byte count * scsi_lib: unnecessary conditional on request type removed [ Impact: cleanup ] Signed-off-by: Tejun Heo Cc: Paul Clements Cc: Pete Zaitcev Cc: Alex Dubov Cc: Markus Lidel Cc: David Woodhouse Cc: James Bottomley Cc: Boaz Harrosh Signed-off-by: Jens Axboe

block: convert to pos and nr_sectors accessors

2009-05-11T07:50:54+00:00

With recent cleanups, there is no place where low level driver directly manipulates request fields. This means that the 'hard' request fields always equal the !hard fields. Convert all rq->sectors, nr_sectors and current_nr_sectors references to accessors. While at it, drop superflous blk_rq_pos() < 0 test in swim.c. [ Impact: use pos and nr_sectors accessors ] Signed-off-by: Tejun Heo Acked-by: Geert Uytterhoeven Tested-by: Grant Likely Acked-by: Grant Likely Tested-by: Adrian McMenamin Acked-by: Adrian McMenamin Acked-by: Mike Miller Cc: James Bottomley Cc: Bartlomiej Zolnierkiewicz Cc: Borislav Petkov Cc: Sergei Shtylyov Cc: Eric Moore Cc: Alan Stern Cc: FUJITA Tomonori Cc: Pete Zaitcev Cc: Stephen Rothwell Cc: Paul Clements Cc: Tim Waugh Cc: Jeff Garzik Cc: Jeremy Fitzhardinge Cc: Alex Dubov Cc: David Woodhouse Cc: Martin Schwidefsky Cc: Dario Ballabio Cc: David S. Miller Cc: Rusty Russell Cc: unsik Kim Cc: Laurent Vivier Signed-off-by: Jens Axboe

nbd: don't clear rq->sector and nr_sectors unnecessarily

2009-05-11T07:50:53+00:00

There's no reason to clear rq->sector and nr_sectors after calling blk_rq_init(). They're guaranteed to be clear. Drop unnecessary clearing. [ Impact: cleanup ] Signed-off-by: Tejun Heo Cc: Paul Clements Signed-off-by: Jens Axboe

nbd: trivial cleanups

2009-04-03T02:05:02+00:00

Trivial cleanups for nbd: only the return -EIO one really changes code, and I've verified all the callers (plus 0 == success, 1 == error convention is really ugly). Signed-off-by: Pavel Machek Acked-by: Paul Clements Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

nbd: add locking to nbd_ioctl

2009-04-03T02:05:02+00:00

The code was written to rely on big kernel lock to protect it from races. It mostly works when interface is not abused. So this uses tx_lock to protect data structures from concurrent use between ioctl and worker threads. Next step will be moving from ioctl to unlocked_ioctl. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: add missing return] Signed-off-by: Pavel Machek Acked-by: Paul Clements Cc: Jens Axboe Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

nbd: fix I/O hang on disconnected nbds

2009-02-11T22:25:37+00:00

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 Cc: [2.6.26.x, 2.6.27.x, 2.6.28.x] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

nbd: do not allow two clients at the same time

2009-01-16T00:39:38+00:00

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