When a filesystem is mounted on a nbd device and on a disconnect, because
of kill_bdev(), and resetting bdev size to zero, buffer_head mappings are
getting destroyed under mounted filesystem.
After a bdev size reset(i.e bdev->bd_inode->i_size = 0) on a disconnect,
followed by a sys_umount(),
generic_shutdown_super()->...
->__sync_blockdev()->...
-blkdev_writepages()->...
->do_invalidatepage()->...
-discard_buffer() is discarding superblock buffer_head assumed
to be in mapped state by ext4_commit_super().
[mlin: ported to 4.11-rc2]
Signed-off-by: Ratna Manoj Bolla <manoj.br@gmail.com
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
We can't just set the timeout on the tagset, we have to set it on the
queue as it would have been setup already at this point.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
We've been relying on the block layer to assume rq->errors being set
translates into -EIO. I noticed in testing that sometimes this isn't
true, and really there's not much of a reason to have a counter instead
of just using -EIO. So set it properly so we don't leak random numbers
to unsuspecting victims.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
We can submit IO in a processes context, which means there can be
pending signals. This isn't a fatal error for NBD, but it does require
some finesse. If the signal happens before we transmit anything then we
are ok, just requeue the request and carry on. However if we've done a
partial transmit we can't allow anything else to be transmitted on this
socket until we transmit the remaining part of the request. Deal with
this by keeping track of how much we've sent for the current request,
and if we get an ERESTARTSYS during any part of our transmission save
the state of that request and requeue the IO. If anybody tries to
submit a request that isn't our pending request then requeue that
request until we are able to service the one that is pending.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Pull block layer fixes from Jens Axboe:
"A collection of fixes for this merge window, either fixes for existing
issues, or parts that were waiting for acks to come in. This pull
request contains:
- Allocation of nvme queues on the right node from Shaohua.
This was ready long before the merge window, but waiting on an ack
from Bjorn on the PCI bit. Now that we have that, the three patches
can go in.
- Two fixes for blk-mq-sched with nvmeof, which uses hctx specific
request allocations. This caused an oops. One part from Sagi, one
part from Omar.
- A loop partition scan deadlock fix from Omar, fixing a regression
in this merge window.
- A three-patch series from Keith, closing up a hole on clearing out
requests on shutdown/resume.
- A stable fix for nbd from Josef, fixing a leak of sockets.
- Two fixes for a regression in this window from Jan, fixing a
problem with one of his earlier patches dealing with queue vs bdi
life times.
- A fix for a regression with virtio-blk, causing an IO stall if
scheduling is used. From me.
- A fix for an io context lock ordering problem. From me"
* 'for-linus' of git://git.kernel.dk/linux-block:
block: Move bdi_unregister() to del_gendisk()
blk-mq: ensure that bd->last is always set correctly
block: don't call ioc_exit_icq() with the queue lock held for blk-mq
block: Initialize bd_bdi on inode initialization
loop: fix LO_FLAGS_PARTSCAN hang
nvme: Complete all stuck requests
blk-mq: Provide freeze queue timeout
blk-mq: Export blk_mq_freeze_queue_wait
nbd: stop leaking sockets
blk-mq: move update of tags->rqs to __blk_mq_alloc_request()
blk-mq: kill blk_mq_set_alloc_data()
blk-mq: make blk_mq_alloc_request_hctx() allocate a scheduler request
blk-mq-sched: Allocate sched reserved tags as specified in the original queue tagset
nvme: allocate nvme_queue in correct node
PCI: add an API to get node from vector
blk-mq: allocate blk_mq_tags and requests in correct node
Pull vfs sendmsg updates from Al Viro:
"More sendmsg work.
This is a fairly separate isolated stuff (there's a continuation
around lustre, but that one was too late to soak in -next), thus the
separate pull request"
* 'work.sendmsg' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
ncpfs: switch to sock_sendmsg()
ncpfs: don't mess with manually advancing iovec on send
ncpfs: sendmsg does *not* bugger iovec these days
ceph_tcp_sendpage(): use ITER_BVEC sendmsg
afs_send_pages(): use ITER_BVEC
rds: remove dead code
ceph: switch to sock_recvmsg()
usbip_recv(): switch to sock_recvmsg()
iscsi_target: deal with short writes on the tx side
[nbd] pass iov_iter to nbd_xmit()
[nbd] switch sock_xmit() to sock_{send,recv}msg()
[drbd] use sock_sendmsg()
This was introduced in the multi-connection patch, we've been leaking
socket's ever since.
Fixes: 9561a7a ("nbd: add multi-connection support")
cc: stable@vger.kernel.org
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
If we fail to register the blockdev we need to make sure to destroy the
recv workqueue.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
We noticed when trying to do O_DIRECT to an export on the server side
that we were getting requests smaller than the 4k sectorsize of the
device. This is because the client isn't setting the logical and
physical blocksizes properly for the underlying device. Fix this up by
setting the queue blocksizes and then calling bd_set_size.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Break the ioctl handling out into helper functions, some of these things
are getting pretty big and unwieldy.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
To prepare for dynamically adding new nbd devices to the system switch
from using an array for the nbd devices and instead use an idr. This
copies what loop does for keeping track of its devices.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Since we are in the memory reclaim path we need our recv work to be on a
workqueue that has WQ_MEM_RECLAIM set so we can avoid deadlocks. Also
set WQ_HIGHPRI since we are in the completion path for IO.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Instead of keeping two levels of indirection for requests types, fold it
all into the operations. The little caveat here is that previously
cmd_type only applied to struct request, while the request and bio op
fields were set to plain REQ_OP_READ/WRITE even for passthrough
operations.
Instead this patch adds new REQ_OP_* for SCSI passthrough and driver
private requests, althought it has to add two for each so that we
can communicate the data in/out nature of the request.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
This is where we do the rest of the request handling, which will
become much simpler soon, too.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Disconnects don't use block layer requests these days, so all handling
of private requests is dead code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
A user noticed that write performance was horrible over loopback and we
traced it to an inversion of when we need to set MSG_MORE. It should be
set when we have more bvec's to send, not when we are on the last bvec.
This patch made the test go from 20 iops to 78k iops.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Fixes: 429a787be6 ("nbd: fix use-after-free of rq/bio in the xmit path")
Signed-off-by: Jens Axboe <axboe@fb.com>
Additionally, don't assign directly to disk->queue, otherwise
blk_put_queue (called via put_disk) will choke (panic) on the errno
stored there.
Bug found by code inspection after Omar found a similar issue in
virtio_blk. Compile-tested only.
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This was entirely automated, using the script by Al:
PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)
to do the replacement at the end of the merge window.
Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While doing stress tests we noticed that we'd get a lot of dmesg spam if
we suddenly disconnected the nbd device out of band. Rate limit the
messages in the io path in order to deal with this.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
If an app exits before running NBD_DO_IT but after adding sockets we can
end up not being allowed to do a new nbd device. Fix this by making
NBD_CLEAR_SOCK reset the setup_task.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
We have this:
ERROR: "__aeabi_ldivmod" [drivers/block/nbd.ko] undefined!
ERROR: "__divdi3" [drivers/block/nbd.ko] undefined!
nbd.c:(.text+0x247c72): undefined reference to `__divdi3'
due to a recent commit, that did 64-bit division. Use the proper
divider function so that 32-bit compiles don't break.
Fixes: ef77b51524 ("nbd: use loff_t for blocksize and nbd_set_size args")
Signed-off-by: Jens Axboe <axboe@fb.com>
If we have large devices (say like the 40t drive I was trying to test with) we
will end up overflowing the int arguments to nbd_set_size and not get the right
size for our device. Fix this by using loff_t everywhere so I don't have to
think about this again. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Multiple paths don't set it properly, ensure that we do.
Fixes: 9561a7ade0 ("nbd: add multi-connection support")
Signed-off-by: Jens Axboe <axboe@fb.com>
NBD can become contended on its single connection. We have to serialize all
writes and we can only process one read response at a time. Fix this by
allowing userspace to provide multiple connections to a single nbd device. This
coupled with block-mq drastically increases performance in multi-process cases.
Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
For writes, we can get a completion in while we're still iterating
the request and bio chain. If that happens, we're reading freed
memory and we can crash.
Break out after the last segment and avoid having the iterator
read freed memory.
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Pull blk-mq irq/cpu mapping updates from Jens Axboe:
"This is the block-irq topic branch for 4.9-rc. It's mostly from
Christoph, and it allows drivers to specify their own mappings, and
more importantly, to share the blk-mq mappings with the IRQ affinity
mappings. It's a good step towards making this work better out of the
box"
* 'for-4.9/block-irq' of git://git.kernel.dk/linux-block:
blk_mq: linux/blk-mq.h does not include all the headers it depends on
blk-mq: kill unused blk_mq_create_mq_map()
blk-mq: get rid of the cpumask in struct blk_mq_tags
nvme: remove the post_scan callout
nvme: switch to use pci_alloc_irq_vectors
blk-mq: provide a default queue mapping for PCI device
blk-mq: allow the driver to pass in a queue mapping
blk-mq: remove ->map_queue
blk-mq: only allocate a single mq_map per tag_set
blk-mq: don't redistribute hardware queues on a CPU hotplug event
We take a mutex when sending commands and send stuff over the network, we need
to have queue_rq called asynchronously.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Fixes: fd8383fd88 ("nbd: convert to blkmq")
Signed-off-by: Jens Axboe <axboe@fb.com>
Instead of rolling our own timer, just utilize the blk mq req timeout and do the
disconnect if any of our commands timeout.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
In preparation for some future changes, change a few of the state bools over to
normal bits to set/clear properly.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
We hit a warning when shutting down the nbd connection because we have irq's
disabled. We don't really need to do the shutdown under the lock, just clear
the nbd->sock. So do the shutdown outside of the irq. This gets rid of the
warning.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This moves NBD over to using blkmq, which allows us to get rid of the NBD
wide queue lock and the async submit kthread. We will start with 1 hw
queue for now, but I plan to add multiple tcp connection support in the
future and we'll fix how we set the hwqueue's.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Quentin ran into this bug:
WARNING: CPU: 64 PID: 10085 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x65/0x80
sysfs: cannot create duplicate filename '/devices/virtual/block/nbd3/pid'
Modules linked in: nbd
CPU: 64 PID: 10085 Comm: qemu-nbd Tainted: G D 4.6.0+ #7
0000000000000000 ffff8820330bba68 ffffffff814b8791 ffff8820330bbac8
0000000000000000 ffff8820330bbab8 ffffffff810d04ab ffff8820330bbaa8
0000001f00000296 0000000000017681 ffff8810380bf000 ffffffffa0001790
Call Trace:
[<ffffffff814b8791>] dump_stack+0x4d/0x6c
[<ffffffff810d04ab>] __warn+0xdb/0x100
[<ffffffff810d0574>] warn_slowpath_fmt+0x44/0x50
[<ffffffff81218c65>] sysfs_warn_dup+0x65/0x80
[<ffffffff81218a02>] sysfs_add_file_mode_ns+0x172/0x180
[<ffffffff81218a35>] sysfs_create_file_ns+0x25/0x30
[<ffffffff81594a76>] device_create_file+0x36/0x90
[<ffffffffa0000e8d>] __nbd_ioctl+0x32d/0x9b0 [nbd]
[<ffffffff814cc8e8>] ? find_next_bit+0x18/0x20
[<ffffffff810f7c29>] ? select_idle_sibling+0xe9/0x120
[<ffffffff810f6cd7>] ? __enqueue_entity+0x67/0x70
[<ffffffff810f9bf0>] ? enqueue_task_fair+0x630/0xe20
[<ffffffff810efa76>] ? resched_curr+0x36/0x70
[<ffffffff810f0078>] ? check_preempt_curr+0x78/0x90
[<ffffffff810f00a2>] ? ttwu_do_wakeup+0x12/0x80
[<ffffffff810f01b1>] ? ttwu_do_activate.constprop.86+0x61/0x70
[<ffffffff810f0c15>] ? try_to_wake_up+0x185/0x2d0
[<ffffffff810f0d6d>] ? default_wake_function+0xd/0x10
[<ffffffff81105471>] ? autoremove_wake_function+0x11/0x40
[<ffffffffa0001577>] nbd_ioctl+0x67/0x94 [nbd]
[<ffffffff814ac0fd>] blkdev_ioctl+0x14d/0x940
[<ffffffff811b0da2>] ? put_pipe_info+0x22/0x60
[<ffffffff811d96cc>] block_ioctl+0x3c/0x40
[<ffffffff811ba08d>] do_vfs_ioctl+0x8d/0x5e0
[<ffffffff811aa329>] ? ____fput+0x9/0x10
[<ffffffff810e9092>] ? task_work_run+0x72/0x90
[<ffffffff811ba627>] SyS_ioctl+0x47/0x80
[<ffffffff8185f5df>] entry_SYSCALL_64_fastpath+0x17/0x93
---[ end trace 7899b295e4f850c8 ]---
It seems fairly obvious that device_create_file() is not being protected
from being run concurrently on the same nbd.
Quentin found the following relevant commits:
1a2ad21 nbd: add locking to nbd_ioctl
90b8f28 [PATCH] end of methods switch: remove the old ones
d4430d6 [PATCH] beginning of methods conversion
08f8585 [PATCH] move block_device_operations to blkdev.h
It would seem that the race was introduced in the process of moving nbd
from BKL to unlocked ioctls.
By setting nbd->task_recv while the mutex is held, we can prevent other
processes from running concurrently (since nbd->task_recv is also checked
while the mutex is held).
Reported-and-tested-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Markus Pargmann <mpa@pengutronix.de>
Cc: Paul Clements <paul.clements@steeleye.com>
Cc: Pavel Machek <pavel@suse.cz>
Cc: Jens Axboe <axboe@fb.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Pull core block updates from Jens Axboe:
- the big change is the cleanup from Mike Christie, cleaning up our
uses of command types and modified flags. This is what will throw
some merge conflicts
- regression fix for the above for btrfs, from Vincent
- following up to the above, better packing of struct request from
Christoph
- a 2038 fix for blktrace from Arnd
- a few trivial/spelling fixes from Bart Van Assche
- a front merge check fix from Damien, which could cause issues on
SMR drives
- Atari partition fix from Gabriel
- convert cfq to highres timers, since jiffies isn't granular enough
for some devices these days. From Jan and Jeff
- CFQ priority boost fix idle classes, from me
- cleanup series from Ming, improving our bio/bvec iteration
- a direct issue fix for blk-mq from Omar
- fix for plug merging not involving the IO scheduler, like we do for
other types of merges. From Tahsin
- expose DAX type internally and through sysfs. From Toshi and Yigal
* 'for-4.8/core' of git://git.kernel.dk/linux-block: (76 commits)
block: Fix front merge check
block: do not merge requests without consulting with io scheduler
block: Fix spelling in a source code comment
block: expose QUEUE_FLAG_DAX in sysfs
block: add QUEUE_FLAG_DAX for devices to advertise their DAX support
Btrfs: fix comparison in __btrfs_map_block()
block: atari: Return early for unsupported sector size
Doc: block: Fix a typo in queue-sysfs.txt
cfq-iosched: Charge at least 1 jiffie instead of 1 ns
cfq-iosched: Fix regression in bonnie++ rewrite performance
cfq-iosched: Convert slice_resid from u64 to s64
block: Convert fifo_time from ulong to u64
blktrace: avoid using timespec
block/blk-cgroup.c: Declare local symbols static
block/bio-integrity.c: Add #include "blk.h"
block/partition-generic.c: Remove a set-but-not-used variable
block: bio: kill BIO_MAX_SIZE
cfq-iosched: temporarily boost queue priority for idle classes
block: drbd: avoid to use BIO_MAX_SIZE
block: bio: remove BIO_MAX_SECTORS
...
We were passing in &nbd for the private data in debugfs_create_file() for the
flags entry. We expect it to just be nbd, fix this so we get proper output from
this debugfs entry.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This adds a REQ_OP_FLUSH operation that is sent to request_fn
based drivers by the block layer's flush code, instead of
sending requests with the request->cmd_flags REQ_FLUSH bit set.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
The req operation REQ_OP is separated from the rq_flag_bits
definition. This converts the block layer drivers to
use req_op to get the op from the request struct.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
The do_div() macro now checks its arguments for the correct type,
and refuses anything other than u64, so we get a warning about
nbd_ioctl passing in an loff_t:
drivers/block/nbd.c: In function '__nbd_ioctl':
drivers/block/nbd.c:757:77: error: comparison of distinct pointer types lacks a cast [-Werror]
This changes the nbd code to use div_s64() instead, which takes
a signed argument.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 37091fdd83 ("nbd: Create size change events for userspace")
Signed-off-by: Jens Axboe <axboe@fb.com>
The userspace needs to know when nbd devices are ready for use.
Currently no events are created for the userspace which doesn't work for
systemd.
See the discussion here: https://github.com/systemd/systemd/pull/358
This patch uses a central point to setup the nbd-internal sizes. A ioctl
to set a size does not lead to a visible size change. The size of the
block device will be kept at 0 until nbd is connected. As soon as it
connects, the size will be changed to the real value and a uevent is
created. When disconnecting, the blockdevice is set to 0 size and
another uevent is generated.
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Make the "Attempted send on closed socket" error messages generated in
nbd_request_handler() ratelimited.
When the nbd socket is shutdown, the nbd_request_handler() function emits
an error message for every request remaining in its queue. If the queue
is large, this will spam a large amount of messages to the log. There's
no need for a separate error message for each request, so this patch
ratelimits it.
In the specific case this was found, the system was virtual and the error
messages were logged to the serial port, which overwhelmed it.
Fixes: 4d48a542b4 ("nbd: fix I/O hang on disconnected nbds")
Signed-off-by: Dan Streetman <dan.streetman@canonical.com>
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
nbd changes properties of the blockdevice depending on flags that were
received. This patch moves this flag parsing into a separate function
nbd_parse_flags().
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Group all variables that are reset after a disconnect into reset
functions. This patch adds two of these functions, nbd_reset() and
nbd_bdev_reset().
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
It may be useful to know in the client that a connection timed out. The
current code returns success for a timeout.
This patch reports the error code -ETIMEDOUT for a timeout.
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
As discussed on the mailing list, the usage of signals for timeout
handling has a lot of potential issues. The nbd driver used for some
time signals for timeouts. These signals where able to get the threads
out of the blocking socket operations.
This patch removes all signal usage and uses a socket shutdown instead.
The socket descriptor itself is cleared later when the whole nbd device
is closed.
The tasks_lock is removed as we do not depend on this anymore. Instead
a new lock for the socket is introduced so we can safely work with the
socket in the timeout handler outside of the two main threads.
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Static checker complains about the implemented error handling. It is
indeed wrong. We don't care about the return values of created debugfs
files.
We only have to check the return values of created dirs for NULL
pointer. If we use a null pointer as parent directory for files, this
may lead to debugfs files in wrong places.
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
1. Rename dequeue_signal_lock() to kernel_dequeue_signal(). This
matches another "for kthreads only" kernel_sigaction() helper.
2. Remove the "tsk" and "mask" arguments, they are always current
and current->blocked. And it is simply wrong if tsk != current.
3. We could also remove the 3rd "siginfo_t *info" arg but it looks
potentially useful. However we can simplify the callers if we
change kernel_dequeue_signal() to accept info => NULL.
4. Remove _irqsave, it is never called from atomic context.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The timeout handling introduced in
7e2893a16d (nbd: Fix timeout detection)
introduces a race condition which may lead to killing of tasks that are
not in nbd context anymore. This was not observed or reproducable yet.
This patch adds locking to critical use of task_recv and task_send to
avoid killing tasks that already left the NBD thread functions. This
lock is only acquired if a timeout occures or the nbd device
starts/stops.
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Reviewed-by: Ben Hutchings <ben@decadent.org.uk>
Fixes: 7e2893a16d ("nbd: Fix timeout detection")
Signed-off-by: Jens Axboe <axboe@fb.com>
