Currently, when a disconnect is requested by the user (via NBD_DISCONNECT
ioctl) the return from NBD_DO_IT is undefined (it is usually one of
several error codes). This means that nbd-client does not know if a
manual disconnect was performed or whether a network error occurred.
Because of this, nbd-client's persist mode (which tries to reconnect after
error, but not after manual disconnect) does not always work correctly.
This change fixes this by causing NBD_DO_IT to always return 0 if a user
requests a disconnect. This means that nbd-client can correctly either
persist the connection (if an error occurred) or disconnect (if the user
requested it).
Signed-off-by: Paul Clements <paul.clements@steeleye.com>
Acked-by: Rob Landley <rob@landley.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>
Add discard support to nbd. If the nbd-server supports discard, it will
send NBD_FLAG_SEND_TRIM to the client. The client will then set the flag
in the kernel via NBD_SET_FLAGS, which tells the kernel to enable discards
for the device (QUEUE_FLAG_DISCARD).
If discard support is enabled, then when the nbd client system receives a
discard request, this will be passed along to the nbd-server. When the
discard request is received by the nbd-server, it will perform:
fallocate(.. FALLOC_FL_PUNCH_HOLE ..)
To punch a hole in the backend storage, which is no longer needed.
Signed-off-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>
Add a set-flags ioctl, allowing various option flags to be set on an nbd
device. This allows the nbd-client to set the device flags (to enable
read-only mode, or enable discard support, etc.).
Flags are typically specified by the nbd-server. During the negotiation
phase of the nbd connection, the server sends its flags to the client.
The client then uses NBD_SET_FLAGS to inform the kernel of the options.
Also included is a one-line fix to debug output for the set-timeout ioctl.
Signed-off-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>
__packed is only defined in kernel space, so we should use
__attribute__((packed)) for the code shared between kernel and user space.
Two __attribute() annotations are replaced with __attribute__() too.
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
cleanup patch.
Use new __packed annotation in net/ and include/
(except netfilter)
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since <linux/compiler.h> already tests for __GNUC__, there's no point in nbd.h
repeating that test.
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Cc: Paul Clements <paul.clements@steeleye.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch allows Network Block Device to be mounted locally (nbd-client to
nbd-server over 127.0.0.1).
It creates a kthread to avoid the deadlock described in NBD tools
documentation. So, if nbd-client hangs waiting for pages, the kblockd thread
can continue its work and free pages.
I have tested the patch to verify that it avoids the hang that always occurs
when writing to a localhost nbd connection. I have also tested to verify that
no performance degradation results from the additional thread and queue.
Patch originally from Laurent Vivier.
Signed-off-by: Paul Clements <paul.clements@steeleye.com>
Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove the arbitrary 128 device limit for NBD. nbds_max can now be set to
any number. In certain scenarios where devices are used sparsely we have
run into the 128 device limit.
Signed-off-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>
Allow NBD I/O to be cancelled when a network outage occurs. Previously, I/O
would just hang, and if enough I/O was hung in nbd, the system (at least
user-level) would completely hang until a TCP timeout (default, 15 minutes)
occurred.
The patch introduces a new ioctl NBD_SET_TIMEOUT that allows a transmit
timeout value (in seconds) to be specified. Any network send that exceeds the
timeout will be cancelled and the nbd connection will be shut down. I've
tested with various timeout values and 6 seconds seems to be a good choice for
the timeout. If the NBD_SET_TIMEOUT ioctl is not called, you get the old (I/O
hang) behavior.
Signed-off-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>
Allow nbd to expose the nbd-client daemon's PID in /sys/block/nbd<x>/pid.
This is helpful for tracking connection status of a device and for
determining which nbd devices are currently in use.
Signed-off-by: Paul Clements <paul.clements@steeleye.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The nbd header uses __be32 and such types but doesn't actually include the
header that defines these things (linux/types.h); so let's include it.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Semaphore to mutex conversion.
The conversion was generated via scripts, and the result was validated
automatically via a script as well.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Paul Clements <Paul.Clements@steeleye.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Janos Haar of First NetCenter Bt. reported numerous crashes involving the
NBD driver. With his help, this was tracked down to bogus bio vectors
which in turn was the result of a race condition between the
receive/transmit routines in the NBD driver.
The bug manifests itself like this:
CPU0 CPU1
do_nbd_request
add req to queuelist
nbd_send_request
send req head
for each bio
kmap
send
nbd_read_stat
nbd_find_request
nbd_end_request
kunmap
When CPU1 finishes nbd_end_request, the request and all its associated
bio's are freed. So when CPU0 calls kunmap whose argument is derived from
the last bio, it may crash.
Under normal circumstances, the race occurs only on the last bio. However,
if an error is encountered on the remote NBD server (such as an incorrect
magic number in the request), or if there were a bug in the server, it is
possible for the nbd_end_request to occur any time after the request's
addition to the queuelist.
The following patch fixes this problem by making sure that requests are not
added to the queuelist until after they have been completed transmission.
In order for the receiving side to be ready for responses involving
requests still being transmitted, the patch introduces the concept of the
active request.
When a response matches the current active request, its processing is
delayed until after the tranmission has come to a stop.
This has been tested by Janos and it has been successful in curing this
race condition.
From: Herbert Xu <herbert@gondor.apana.org.au>
Here is an updated patch which removes the active_req wait in
nbd_clear_queue and the associated memory barrier.
I've also clarified this in the comment.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Cc: <djani22@dynamicweb.hu>
Cc: Paul Clements <Paul.Clements@SteelEye.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Paul Clements