Commit Graph

317 Commits

Author SHA1 Message Date
Eric Blake
1f4d6d18ed nbd: Implement NBD_CMD_WRITE_ZEROES on server
Upstream NBD protocol recently added the ability to efficiently
write zeroes without having to send the zeroes over the wire,
along with a flag to control whether the client wants to allow
a hole.

Note that when it comes to requiring full allocation, vs.
permitting optimizations, the NBD spec intentionally picked a
different sense for the flag; the rules in qemu are:
MAY_UNMAP == 0: must write zeroes
MAY_UNMAP == 1: may use holes if reads will see zeroes

while in NBD, the rules are:
FLAG_NO_HOLE == 1: must write zeroes
FLAG_NO_HOLE == 0: may use holes if reads will see zeroes

In all cases, the 'may use holes' scenario is optional (the
server need not use a hole, and must not use a hole if
subsequent reads would not see zeroes).

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-16-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02 09:28:56 +01:00
Eric Blake
b6f5d3b573 nbd: Improve server handling of shutdown requests
NBD commit 6d34500b clarified how clients and servers are supposed
to behave before closing a connection. It added NBD_REP_ERR_SHUTDOWN
(for the server to announce it is about to go away during option
haggling, so the client should quit sending NBD_OPT_* other than
NBD_OPT_ABORT) and ESHUTDOWN (for the server to announce it is about
to go away during transmission, so the client should quit sending
NBD_CMD_* other than NBD_CMD_DISC).  It also clarified that
NBD_OPT_ABORT gets a reply, while NBD_CMD_DISC does not.

This patch merely adds the missing reply to NBD_OPT_ABORT and teaches
the client to recognize server errors.  Actually teaching the server
to send NBD_REP_ERR_SHUTDOWN or ESHUTDOWN would require knowing that
the server has been requested to shut down soon (maybe we could do
that by installing a SIGINT handler in qemu-nbd, which transitions
from RUNNING to a new state that waits for the client to react,
rather than just out-right quitting - but that's a bigger task for
another day).

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-15-git-send-email-eblake@redhat.com>
[Move dummy ESHUTDOWN to include/qemu/osdep.h. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02 09:28:56 +01:00
Eric Blake
8b34a9dbc3 nbd: Refactor conversion to errno to silence checkpatch
Checkpatch complains that 'return EINVAL' is usually wrong
(since we tend to favor 'return -EINVAL').  But it is a
false positive for nbd_errno_to_system_errno().  Since NBD
may add future defined wire values, refactor the code to
keep checkpatch happy.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-14-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02 09:28:56 +01:00
Eric Blake
c203c59ad9 nbd: Support shorter handshake
The NBD Protocol allows the server and client to mutually agree
on a shorter handshake (omit the 124 bytes of reserved 0), via
the server advertising NBD_FLAG_NO_ZEROES and the client
acknowledging with NBD_FLAG_C_NO_ZEROES (only possible in
newstyle, whether or not it is fixed newstyle).  It doesn't
shave much off the wire, but we might as well implement it.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alex Bligh <alex@alex.org.uk>
Message-Id: <1476469998-28592-13-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02 09:28:56 +01:00
Eric Blake
75368aab9b nbd: Less allocation during NBD_OPT_LIST
Since we know that the maximum name we are willing to accept
is small enough to stack-allocate, rework the iteration over
NBD_OPT_LIST responses to reuse a stack buffer rather than
allocating every time.  Furthermore, we don't even have to
allocate if we know the server's length doesn't match what
we are searching for.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-12-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02 09:28:55 +01:00
Eric Blake
7d3123e177 nbd: Let client skip portions of server reply
The server has a nice helper function nbd_negotiate_drop_sync()
which lets it easily ignore fluff from the client (such as the
payload to an unknown option request).  We can't quite make it
common, since it depends on nbd_negotiate_read() which handles
coroutine magic, but we can copy the idea into the client where
we have places where we want to ignore data (such as the
description tacked on the end of NBD_REP_SERVER).

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-11-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02 09:28:55 +01:00
Eric Blake
2cdbf41362 nbd: Let server know when client gives up negotiation
The NBD spec says that a client should send NBD_OPT_ABORT
rather than just dropping the connection, if the client doesn't
like something the server sent during option negotiation.  This
is a best-effort attempt only, and can only be done in places
where we know the server is still in sync with what we've sent,
whether or not we've read everything the server has sent.
Technically, the server then has to reply with NBD_REP_ACK, but
it's not worth complicating the client to wait around for that
reply.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-10-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02 09:28:55 +01:00
Eric Blake
c8a3a1b6c4 nbd: Share common option-sending code in client
Rather than open-coding each option request, it's easier to
have common helper functions do the work.  That in turn requires
having convenient packed types for handling option requests
and replies.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-9-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02 09:28:55 +01:00
Eric Blake
3668328303 nbd: Send message along with server NBD_REP_ERR errors
The NBD Protocol allows us to send human-readable messages
along with any NBD_REP_ERR error during option negotiation;
make use of this fact for clients that know what to do with
our message.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-8-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02 09:28:55 +01:00
Eric Blake
526e5c6559 nbd: Share common reply-sending code in server
Rather than open-coding NBD_REP_SERVER, reuse the code we
already have by adding a length parameter.  Additionally,
the refactoring will make adding NBD_OPT_GO in a later patch
easier.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-7-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02 09:28:55 +01:00
Eric Blake
ed2dd91267 nbd: Rename struct nbd_request and nbd_reply
Our coding convention prefers CamelCase names, and we already
have other existing structs with NBDFoo naming.  Let's be
consistent, before later patches add even more structs.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-6-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02 09:28:55 +01:00
Eric Blake
315f78abfc nbd: Rename NBDRequest to NBDRequestData
We have both 'struct NBDRequest' and 'struct nbd_request'; making
it confusing to see which does what.  Furthermore, we want to
rename nbd_request to align with our normal CamelCase naming
conventions.  So, rename the struct which is used to associate
the data received during request callbacks, while leaving the
shorter name for the description of the request sent over the
wire in the NBD protocol.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-4-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02 09:28:55 +01:00
Eric Blake
b626b51a67 nbd: Treat flags vs. command type as separate fields
Current upstream NBD documents that requests have a 16-bit flags,
followed by a 16-bit type integer; although older versions mentioned
only a 32-bit field with masking to find flags.  Since the protocol
is in network order (big-endian over the wire), the ABI is unchanged;
but dealing with the flags as a separate field rather than masking
will make it easier to add support for upcoming NBD extensions that
increase the number of both flags and commands.

Improve some comments in nbd.h based on the current upstream
NBD protocol (https://github.com/yoe/nbd/blob/master/doc/proto.md),
and touch some nearby code to keep checkpatch.pl happy.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-3-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02 09:28:55 +01:00
Eric Blake
b1a75b3348 nbd: Add qemu-nbd -D for human-readable description
The NBD protocol allows servers to advertise a human-readable
description alongside an export name during NBD_OPT_LIST.  Add
an option to pass through the user's string to the NBD client.

Doing this also makes it easier to test commit 200650d4, which
is the client counterpart of receiving the description.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-2-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02 09:28:55 +01:00
Daniel P. Berrange
0d73f7253e nbd: set name for all I/O channels created
Ensure that all I/O channels created for NBD are given names
to distinguish their respective roles.

Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2016-10-27 09:13:10 +02:00
Kevin Wolf
cd7fca952c nbd-server: Use a separate BlockBackend
The builtin NBD server uses its own BlockBackend now instead of reusing
the monitor/guest device one.

This means that it has its own writethrough setting now. The builtin
NBD server always uses writeback caching now regardless of whether the
guest device has WCE enabled. qemu-nbd respects the cache mode given on
the command line.

We still need to keep a reference to the monitor BB because we put an
eject notifier on it, but we don't use it for any I/O.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2016-09-05 19:06:47 +02:00
Eric Blake
7423f41782 nbd: Limit nbdflags to 16 bits
Rather than asserting that nbdflags is within range, just give
it the correct type to begin with :)  nbdflags corresponds to
the per-export portion of NBD Protocol "transmission flags", which
is 16 bits in response to NBD_OPT_EXPORT_NAME and NBD_OPT_GO.

Furthermore, upstream NBD has never passed the global flags to
the kernel via ioctl(NBD_SET_FLAGS) (the ioctl was first
introduced in NBD 2.9.22; then a latent bug in NBD 3.1 actually
tried to OR the global flags with the transmission flags, with
the disaster that the addition of NBD_FLAG_NO_ZEROES in 3.9
caused all earlier NBD 3.x clients to treat every export as
read-only; NBD 3.10 and later intentionally clip things to 16
bits to pass only transmission flags).  Qemu should follow suit,
since the current two global flags (NBD_FLAG_FIXED_NEWSTYLE
and NBD_FLAG_NO_ZEROES) have no impact on the kernel's behavior
during transmission.

CC: qemu-stable@nongnu.org
Signed-off-by: Eric Blake <eblake@redhat.com>

Message-Id: <1469129688-22848-3-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-08-03 18:44:56 +02:00
Eric Blake
5bee0f4717 nbd: Fix bad flag detection on server
Commit ab7c548e added a check for invalid flags, but used an
early return on error instead of properly going through the
cleanup label.

Signed-off-by: Eric Blake <eblake@redhat.com>

Message-Id: <1469129688-22848-2-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-08-03 18:44:56 +02:00
Eric Blake
1c6c4bb7f0 block: Convert BB interface to byte-based discards
Change sector-based blk_discard(), blk_co_discard(), and
blk_aio_discard() to instead be byte-based blk_pdiscard(),
blk_co_pdiscard(), and blk_aio_pdiscard().  NBD gets a lot
simpler now that ignoring the unaligned portion of a
byte-based discard request is handled under the hood by
the block layer.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1468624988-423-6-git-send-email-eblake@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-20 14:11:55 +01:00
Eric Blake
1e2a77a851 nbd: Drop unused offset parameter
Now that NBD relies on the block layer to fragment things, we no
longer need to track an offset argument for which fragment of
a request we are actually servicing.

While at it, use true and false instead of 0 and 1 for a bool
parameter.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1468607524-19021-6-git-send-email-eblake@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-20 14:11:54 +01:00
Paolo Bonzini
0b8b8753e4 coroutine: move entry argument to qemu_coroutine_create
In practice the entry argument is always known at creation time, and
it is confusing that sometimes qemu_coroutine_enter is used with a
non-NULL argument to re-enter a coroutine (this happens in
block/sheepdog.c and tests/test-coroutine.c).  So pass the opaque value
at creation time, for consistency with e.g. aio_bh_new.

Mostly done with the following semantic patch:

@ entry1 @
expression entry, arg, co;
@@
- co = qemu_coroutine_create(entry);
+ co = qemu_coroutine_create(entry, arg);
  ...
- qemu_coroutine_enter(co, arg);
+ qemu_coroutine_enter(co);

@ entry2 @
expression entry, arg;
identifier co;
@@
- Coroutine *co = qemu_coroutine_create(entry);
+ Coroutine *co = qemu_coroutine_create(entry, arg);
  ...
- qemu_coroutine_enter(co, arg);
+ qemu_coroutine_enter(co);

@ entry3 @
expression entry, arg;
@@
- qemu_coroutine_enter(qemu_coroutine_create(entry), arg);
+ qemu_coroutine_enter(qemu_coroutine_create(entry, arg));

@ reentry @
expression co;
@@
- qemu_coroutine_enter(co, NULL);
+ qemu_coroutine_enter(co);

except for the aforementioned few places where the semantic patch
stumbled (as expected) and for test_co_queue, which would otherwise
produce an uninitialized variable warning.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-07-13 13:26:02 +02:00
Peter Maydell
d121fcdf45 nbd/client.c: Correct trace format string
The trace format string in nbd_send_request uses PRIu16 for
request->type, but request->type is a uint32_t. This provokes
compiler warnings on the OSX clang. Use PRIu32 instead.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1466167331-17063-1-git-send-email-peter.maydell@linaro.org
2016-06-17 15:05:55 +01:00
Eric Blake
943cec86d0 nbd: Avoid magic number for NBD max name size
Declare a constant and use that when determining if an export
name fits within the constraints we are willing to support.

Note that upstream NBD recently documented that clients MUST
support export names of 256 bytes (not including trailing NUL),
and SHOULD support names up to 4096 bytes.  4096 is a bit big
(we would lose benefits of stack-allocation of a name array),
and we already have other limits in place (for example, qcow2
snapshot names are clamped around 1024).  So for now, just
stick to the required minimum, as that's easier to audit than
a full-scale support for larger names.

Signed-off-by: Eric Blake <eblake@redhat.com>

Message-Id: <1463006384-7734-12-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16 18:39:05 +02:00
Eric Blake
f3c32fce36 nbd: Detect servers that send unexpected error values
Add some debugging to flag servers that are not compliant to
the NBD protocol.  This would have flagged the server bug
fixed in commit c0301fcc.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alex Bligh <alex@alex.org.uk>

Message-Id: <1463006384-7734-11-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16 18:39:05 +02:00
Eric Blake
f57e2416aa nbd: Clean up ioctl handling of qemu-nbd -c
The kernel ioctl() interface into NBD is limited to 'unsigned long';
we MUST pass in input with that type (and not int or size_t, as
there may be platform ABIs where the wrong types promote incorrectly
through var-args).  Furthermore, on 32-bit platforms, the kernel
is limited to a maximum export size of 2T (our BLKSIZE of 512 times
a SIZE_BLOCKS constrained by 32 bit unsigned long).

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1463006384-7734-8-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16 18:39:05 +02:00
Eric Blake
98494e3b92 nbd: Group all Linux-specific ioctl code in one place
NBD ioctl()s are used to manage an NBD client session where
initial handshake is done in userspace, but then the transmission
phase is handed off to the kernel through a /dev/nbdX device.
As such, all ioctls sent to the kernel on the /dev/nbdX fd belong
in client.c; nbd_disconnect() was out-of-place in server.c.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1463006384-7734-7-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16 18:39:05 +02:00
Eric Blake
ab7c548e26 nbd: Reject unknown request flags
The NBD protocol says that clients should not send a command flag
that has not been negotiated (whether by the client requesting an
option during a handshake, or because we advertise support for the
flag in response to NBD_OPT_EXPORT_NAME), and that servers should
reject invalid flags with EINVAL.  We were silently ignoring the
flags instead.  The client can't rely on our behavior, since it is
their fault for passing the bad flag in the first place, but it's
better to be robust up front than to possibly behave differently
than the client was expecting with the attempted flag.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alex Bligh <alex@alex.org.uk>
Message-Id: <1463006384-7734-6-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16 18:39:05 +02:00
Eric Blake
29b6c3b319 nbd: Improve server handling of bogus commands
We have a few bugs in how we handle invalid client commands:

- A client can send an NBD_CMD_DISC where from + len overflows,
convincing us to reply with an error and stay connected, even
though the protocol requires us to silently disconnect. Fix by
hoisting the special case sooner.

- A client can send an NBD_CMD_WRITE where from + len overflows,
where we reply to the client with EINVAL without consuming the
payload; this will normally cause us to fail if the next thing
read is not the right magic, but in rare cases, could cause us
to interpret the data payload as valid commands and do things
not requested by the client. Fix by adding a complete flag to
track whether we are in sync or must disconnect.

Furthermore, we have split the checks for bogus from/len across
two functions, when it is easier to do it all at once.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1463006384-7734-5-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16 18:39:05 +02:00
Eric Blake
63d5ef869e nbd: Quit server after any write error
We should never ignore failure from nbd_negotiate_send_rep(); if
we are unable to write to the client, then it is not worth trying
to continue the negotiation.  Fortunately, the problem is not
too severe - chances are that the errors being ignored here (mainly
inability to write the reply to the client) are indications of
a closed connection or something similar, which will also affect
the next attempt to interact with the client and eventually reach
a point where the errors are detected to end the loop.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1463006384-7734-4-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16 18:39:05 +02:00
Eric Blake
2cb347493c nbd: More debug typo fixes, use correct formats
Clean up some debug message oddities missed earlier; this includes
some typos, and recognizing that %d is not necessarily compatible
with uint32_t. Also add a couple messages that I found useful
while debugging things.

Signed-off-by: Eric Blake <eblake@redhat.com>

Message-Id: <1463006384-7734-3-git-send-email-eblake@redhat.com>
[Do not use PRIx16, clang complains. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16 18:39:05 +02:00
Eric Blake
a0c303693e nbd: Use BDRV_REQ_FUA for better FUA where supported
Rather than always flushing ourselves, let the block layer
forward the FUA on to the underlying device - where all
underlying layers also understand FUA, we are now more
efficient; and where any underlying layer doesn't understand
it, now the block layer takes care of the full flush fallback
on our behalf.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1463006384-7734-2-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16 18:39:04 +02:00
Peter Maydell
f6be672084 nbd: Don't use cpu_to_*w() functions
The cpu_to_*w() functions just compose a pointer dereference
with a byteswap. Instead use st*_p(), which handles potential
pointer misalignment and avoids the need to cast the pointer.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <1465575342-12146-1-git-send-email-peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16 18:39:04 +02:00
Peter Maydell
773dce3c72 nbd: Don't use *_to_cpup() functions
The *_to_cpup() functions are not very useful, as they simply do
a pointer dereference and then a *_to_cpu(). Instead use either:
 * ld*_*_p(), if the data is at an address that might not be
   correctly aligned for the load
 * a local dereference and *_to_cpu(), if the pointer is
   the correct type and known to be correctly aligned

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <1465570836-22211-1-git-send-email-peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16 18:39:04 +02:00
Eric Blake
353ab96973 nbd: Don't trim unrequested bytes
Similar to commit df7b97ff, we are mishandling clients that
give an unaligned NBD_CMD_TRIM request, and potentially
trimming bytes that occur before their request; which in turn
can cause potential unintended data loss (unlikely in
practice, since most clients are sane and issue aligned trim
requests).  However, while we fixed read and write by switching
to the byte interfaces of blk_, we don't yet have a byte
interface for discard.  On the other hand, trim is advisory, so
rounding the user's request to simply ignore the first and last
unaligned sectors (or the entire request, if it is sub-sector
in length) is just fine.

CC: qemu-stable@nongnu.org
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1464173965-9694-1-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-29 09:11:10 +02:00
Paolo Bonzini
58369e22cf qemu-common: stop including qemu/bswap.h from qemu-common.h
Move it to the actual users.  There are still a few includes of
qemu/bswap.h in headers; removing them is left for future work.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-19 16:42:28 +02:00
Stefan Weil
cb8d4c8f54 Fix some typos found by codespell
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2016-05-18 15:04:27 +03:00
Eric Blake
8341f00dc2 block: Allow BDRV_REQ_FUA through blk_pwrite()
We have several block drivers that understand BDRV_REQ_FUA,
and emulate it in the block layer for the rest by a full flush.
But without a way to actually request BDRV_REQ_FUA during a
pass-through blk_pwrite(), FUA-aware block drivers like NBD are
forced to repeat the emulation logic of a full flush regardless
of whether the backend they are writing to could do it more
efficiently.

This patch just wires up a flags argument; followup patches
will actually make use of it in the NBD driver and in qemu-io.

Signed-off-by: Eric Blake <eblake@redhat.com>
Acked-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-05-12 15:22:08 +02:00
Eric Blake
df7b97ff89 nbd: Don't mishandle unaligned client requests
The NBD protocol does not (yet) force any alignment constraints
on clients.  Even though qemu NBD clients always send requests
that are aligned to 512 bytes, we must be prepared for non-qemu
clients that don't care about alignment (even if it means they
are less efficient).  Our use of blk_read() and blk_write() was
silently operating on the wrong file offsets when the client
made an unaligned request, corrupting the client's data (but
as the client already has control over the file we are serving,
I don't think it is a security hole, per se, just a data
corruption bug).

Note that in the case of NBD_CMD_READ, an unaligned length could
cause us to return up to 511 bytes of uninitialized trailing
garbage from blk_try_blockalign() - hopefully nothing sensitive
from the heap's prior usage is ever leaked in that manner.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Tested-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1461249750-31928-1-git-send-email-eblake@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-04-22 11:55:35 +01:00
Eric Blake
d1129a8ad9 nbd: Don't kill server on client that doesn't request TLS
Upstream NBD documents (as of commit 4feebc95) that servers MAY
choose to operate in a conditional mode, where it is up to the
client whether to use TLS.  For qemu's case, we want to always be
in FORCEDTLS mode, because of the risk of man-in-the-middle
attacks, and since we never export more than one device; likewise,
the qemu client will ALWAYS send NBD_OPT_STARTTLS as its first
option.  But now that SELECTIVETLS servers exist, it is feasible
to encounter a (non-qemu) client that is programmed to talk to
such a server, and does not do NBD_OPT_STARTTLS first, but rather
wants to probe if it can use a non-encrypted export.

The NBD protocol documents that we should let such a client
continue trying, on the grounds that maybe the client will get the
hint to send NBD_OPT_STARTTLS, rather than immediately dropping
the connection.

Note that NBD_OPT_EXPORT_NAME is a special case: since it is the
only option request that can't have an error return, we have to
(continue to) drop the connection on that one; rather, what we are
fixing here is that all other replies prior to TLS initiation tell
the client NBD_REP_ERR_TLS_REQD, but keep the connection alive.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-id: 1460671343-18485-1-git-send-email-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2016-04-15 17:56:56 +02:00
Eric Blake
200650d49f nbd: Don't fail handshake on NBD_OPT_LIST descriptions
The NBD Protocol states that NBD_REP_SERVER may set
'length > sizeof(namelen) + namelen'; in which case the rest
of the packet is a UTF-8 description of the export.  While we
don't know of any NBD servers that send this description yet,
we had better consume the data so we don't choke when we start
to talk to such a server.

Also, a (buggy/malicious) server that replies with length <
sizeof(namelen) would cause us to block waiting for bytes that
the server is not sending, and one that replies with super-huge
lengths could cause us to temporarily allocate up to 4G memory.
Sanity check things before blindly reading incorrectly.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-id: 1460077777-31004-1-git-send-email-eblake@redhat.com
Reviewed-by: Alex Bligh <alex@alex.org.uk>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2016-04-15 17:56:56 +02:00
Paolo Bonzini
dacca04c8d nbd: do not hang nbd_wr_syncv if outside a coroutine and no available data
Until commit 1c778ef7 ("nbd: convert to using I/O channels for actual
socket I/O", 2016-02-16), nbd_wr_sync returned -EAGAIN this scenario.
nbd_reply_ready required these semantics because it has two conflicting
requirements:

1) if a reply can be received on the socket, nbd_reply_ready needs
to read the header outside coroutine context to identify _which_
coroutine to enter to process the rest of the reply

2) on the other hand, nbd_reply_ready can find a false positive if
another thread (e.g. a VCPU thread running aio_poll) sneaks in and
calls nbd_reply_ready too.  In this case nbd_reply_ready does nothing
and expects nbd_wr_syncv to return -EAGAIN.

Currently, the solution to the first requirement is to wait in the very
rare case of a read() that doesn't retrieve the reply header in its
entirety; this is what nbd_wr_syncv does by calling qio_channel_wait().
However, the unconditional call to qio_channel_wait() breaks the second
requirement.  To fix this, the patch makes nbd_wr_syncv return -EAGAIN
if done is zero, similar to the code before commit 1c778ef7.

This is okay because NBD client-side negotiation is the only other case
that calls nbd_wr_syncv outside a coroutine, and it places the socket
in blocking mode.  On the other hand, it is a bit unpleasant to put
this in nbd_wr_syncv(), because the function is used by both client
and server.

The full fix would be to add a counter to NbdClientSession for how
many bytes have been filled in s->reply.  Then a reply can be filled
by multiple separate invocations of nbd_reply_ready and the
qio_channel_wait() call can be removed completely.  Something to
consider for 2.7...

Reported-by: Changlong Xie <xiecl.fnst@cn.fujitsu.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-04-08 00:07:44 +02:00
Eric Blake
156f6a10c2 nbd: Don't kill server when client requests unknown option
nbd-server.c currently fails to handle unsupported options properly.
If during option haggling the client sends an unknown request, the
server kills the connection instead of letting the client try to
fall back to something older.  This is precisely what advertising
NBD_FLAG_FIXED_NEWSTYLE was supposed to fix.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1459982918-32229-1-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-04-08 00:07:44 +02:00
Alex Bligh
6ff5816478 nbd: Fix NBD unsupported options
nbd-client.c currently fails to handle unsupported options properly.
If during option haggling the server finds an option that is
unsupported, it returns an NBD_REP_ERR_UNSUP reply.

According to nbd's proto.md, the format for such a reply
should be:

  S: 64 bits, 0x3e889045565a9 (magic number for replies)
  S: 32 bits, the option as sent by the client to which this is a reply
  S: 32 bits, reply type (e.g., NBD_REP_ACK for successful completion,
     or NBD_REP_ERR_UNSUP to mark use of an option not known by this server
  S: 32 bits, length of the reply. This may be zero for some replies,
     in which case the next field is not sent
  S: any data as required by the reply (e.g., an export name in the case
     of NBD_REP_SERVER, or optional UTF-8 message for NBD_REP_ERR_*)

However, in nbd-client.c, the reply type was being read, and if it
contained an error, it was bailing out and issuing the next option
request without first reading the length. This meant that the
next option / handshake read had an extra 4 or more bytes of data in it.
In practice, this makes Qemu incompatible with servers that do not
support NBD_OPT_LIST.

To verify this isn't an error in the specification or my reading of
it, replies are sent by the reference implementation here:
 https://github.com/yoe/nbd/blob/66dfb35/nbd-server.c#L1232
and as is evident it always sends a 'datasize' (aka length) 32 bit
word. Unsupported elements are replied to here:
 https://github.com/yoe/nbd/blob/66dfb35/nbd-server.c#L1371

Signed-off-by: Alex Bligh <alex@alex.org.uk>
Message-Id: <1459882500-24316-1-git-send-email-alex@alex.org.uk>
[rework to ALWAYS consume an optional UTF-8 message from the server]
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1459961962-18771-1-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-04-08 00:07:44 +02:00
Eric Blake
7548fe3116 nbd: Improve debug traces on little-endian
Print debug tracing messages while data is still in native
ordering, rather than after we've potentially swapped it into
network order for transmission.  Also, it's nice if the server
mentions what it is replying, to correlate it to with what the
client says it is receiving.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1459913704-19949-4-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-04-08 00:07:44 +02:00
Eric Blake
8c6597123a nbd: Avoid bitrot in TRACE() usage
The compiler is smart enough to optimize out 'if (0)', but won't
type-check our printfs if they are hidden behind #if.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1459913704-19949-3-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-04-08 00:07:43 +02:00
Eric Blake
c0301fcc81 nbd: Return correct error for write to read-only export
The NBD Protocol requires that servers should send EPERM for
attempts to write (or trim) a read-only export.  We were
correct for TRIM (blk_co_discard() gave EPERM); but were
manually setting EROFS which then got mapped to EINVAL over
the wire on writes.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1459913704-19949-2-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-04-08 00:07:43 +02:00
Eric Blake
b6afc654ae nbd: Fix poor debug message
The client sends messages to the server, not itself.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1459459222-8637-3-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-04-05 11:46:52 +02:00
Markus Armbruster
da34e65cb4 include/qemu/osdep.h: Don't include qapi/error.h
Commit 57cb38b included qapi/error.h into qemu/osdep.h to get the
Error typedef.  Since then, we've moved to include qemu/osdep.h
everywhere.  Its file comment explains: "To avoid getting into
possible circular include dependencies, this file should not include
any other QEMU headers, with the exceptions of config-host.h,
compiler.h, os-posix.h and os-win32.h, all of which are doing a
similar job to this file and are under similar constraints."
qapi/error.h doesn't do a similar job, and it doesn't adhere to
similar constraints: it includes qapi-types.h.  That's in excess of
100KiB of crap most .c files don't actually need.

Add the typedef to qemu/typedefs.h, and include that instead of
qapi/error.h.  Include qapi/error.h in .c files that need it and don't
get it now.  Include qapi-types.h in qom/object.h for uint16List.

Update scripts/clean-includes accordingly.  Update it further to match
reality: replace config.h by config-target.h, add sysemu/os-posix.h,
sysemu/os-win32.h.  Update the list of includes in the qemu/osdep.h
comment quoted above similarly.

This reduces the number of objects depending on qapi/error.h from "all
of them" to less than a third.  Unfortunately, the number depending on
qapi-types.h shrinks only a little.  More work is needed for that one.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
[Fix compilation without the spice devel packages. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-22 22:20:15 +01:00
Peter Maydell
30456d5ba3 all: Clean up includes
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.

This commit was created with scripts/clean-includes.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
2016-02-23 12:43:05 +00:00
Daniel P. Berrange
f95910fe6b nbd: implement TLS support in the protocol negotiation
This extends the NBD protocol handling code so that it is capable
of negotiating TLS support during the connection setup. This involves
requesting the STARTTLS protocol option before any other NBD options.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1455129674-17255-14-git-send-email-berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-02-16 17:16:28 +01:00
Daniel P. Berrange
69b49502d8 nbd: use "" as a default export name if none provided
If the user does not provide an export name and the server
is running the new style protocol, where export names are
mandatory, use "" as the default export name if the user
has not specified any. "" is defined in the NBD protocol
as the default name to use in such scenarios.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1455129674-17255-13-git-send-email-berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-02-16 17:16:20 +01:00
Daniel P. Berrange
9344e5f554 nbd: always query export list in fixed new style protocol
With the new style protocol, the NBD client will currenetly
send NBD_OPT_EXPORT_NAME as the first (and indeed only)
option it wants. The problem is that the NBD protocol spec
does not allow for returning an error message with the
NBD_OPT_EXPORT_NAME option. So if the server mandates use
of TLS, the client will simply see an immediate connection
close after issuing NBD_OPT_EXPORT_NAME which is not user
friendly.

To improve this situation, if we have the fixed new style
protocol, we can sent NBD_OPT_LIST as the first option
to query the list of server exports. We can check for our
named export in this list and raise an error if it is not
found, instead of going ahead and sending NBD_OPT_EXPORT_NAME
with a name that we know will be rejected.

This improves the error reporting both in the case that the
server required TLS, and in the case that the client requested
export name does not exist on the server.

If the server does not support NBD_OPT_LIST, we just ignore
that and carry on with NBD_OPT_EXPORT_NAME as before.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1455129674-17255-12-git-send-email-berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-02-16 17:16:11 +01:00
Daniel P. Berrange
e2a9d9a39d nbd: make client request fixed new style if advertised
If the server advertises support for the fixed new style
negotiation, the client should in turn enable new style.
This will allow the client to negotiate further NBD
options besides the export name.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1455129674-17255-10-git-send-email-berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-02-16 17:14:33 +01:00
Daniel P. Berrange
26afa868db nbd: make server compliant with fixed newstyle spec
If the client does not request the fixed new style protocol,
then we should only accept NBD_OPT_EXPORT_NAME. All other
options are only valid when fixed new style has been activated.

The qemu-nbd client doesn't currently request fixed new style
protocol, but this change won't break qemu-nbd, because it
fortunately only ever uses NBD_OPT_EXPORT_NAME, so was never
triggering the non-compliant server behaviour.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1455129674-17255-9-git-send-email-berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-02-16 17:14:24 +01:00
Daniel P. Berrange
f72d705f0d nbd: invert client logic for negotiating protocol version
The nbd_receive_negotiate() method takes different code
paths based on whether 'name == NULL', and then checks
the expected protocol version in each branch.

This patch inverts the logic, so that it takes different
code paths based on what protocol version it receives and
then checks if name is NULL or not as needed.

This facilitates later code which allows the client to
be capable of using the new style protocol regardless
of whether an export name is listed or not.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1455129674-17255-8-git-send-email-berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-02-16 17:14:08 +01:00
Daniel P. Berrange
1c778ef729 nbd: convert to using I/O channels for actual socket I/O
Now that all callers are converted to use I/O channels for
initial connection setup, it is possible to switch the core
NBD protocol handling core over to use QIOChannel APIs for
actual sockets I/O.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1455129674-17255-7-git-send-email-berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-02-16 17:13:57 +01:00
John Snow
667ad26ff8 nbd: avoid unaligned uint64_t store
cpu_to_be64w can't be used to make unaligned stores, but stq_be_p can.
Also, the st?_be_p takes a void* so it is more clearly suited to the
case where you're writing into a byte buffer.

Use the st?_be_p family of functions everywhere in nbd/server.c.

Signed-off-by: John Snow <jsnow@redhat.com>
[Changed to use st?_be_p everywhere. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-02-09 15:45:26 +01:00
Peter Maydell
d38ea87ac5 all: Clean up includes
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.

This commit was created with scripts/clean-includes.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1454089805-5470-16-git-send-email-peter.maydell@linaro.org
2016-02-04 17:41:30 +00:00
Max Reitz
741cc43133 nbd: Switch from close to eject notifier
The NBD code uses the BDS close notifier to determine when a medium is
ejected. However, now it should use the BB's BDS removal notifier for
that instead of the BDS's close notifier.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-02-02 17:50:46 +01:00
Max Reitz
d3780c2dce nbd: client_close on error in nbd_co_client_start
Use client_close() if an error in nbd_co_client_start() occurs instead
of manually inlining parts of it. This fixes an assertion error on the
server side if nbd_negotiate() fails.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-02-02 17:49:42 +01:00
Peter Maydell
ba3fb2f023 * chardev support for TLS and leak fix
* NBD fix from Denis
 * condvar fix from Dave
 * kvm_stat and dump-guest-memory almost rewrite
 * mem-prealloc fix from Luiz
 * manpage style improvement
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Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging

* chardev support for TLS and leak fix
* NBD fix from Denis
* condvar fix from Dave
* kvm_stat and dump-guest-memory almost rewrite
* mem-prealloc fix from Luiz
* manpage style improvement

# gpg: Signature made Tue 26 Jan 2016 14:58:18 GMT using RSA key ID 78C7AE83
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>"
# gpg:                 aka "Paolo Bonzini <pbonzini@redhat.com>"

* remotes/bonzini/tags/for-upstream: (49 commits)
  scripts/dump-guest-memory.py: Fix module docstring
  scripts/dump-guest-memory.py: Introduce multi-arch support
  scripts/dump-guest-memory.py: Cleanup functions
  scripts/dump-guest-memory.py: Improve python 3 compatibility
  scripts/dump-guest-memory.py: Make methods functions
  scripts/dump-guest-memory.py: Move constants to the top
  nbd: add missed aio_context_acquire in nbd_export_new
  memory: exit when hugepage allocation fails if mem-prealloc
  cpus: use broadcast on qemu_pause_cond
  scripts/kvm/kvm_stat: Add optparse description
  scripts/kvm/kvm_stat: Add interactive filtering
  scripts/kvm/kvm_stat: Fixup filtering
  scripts/kvm/kvm_stat: Fix rlimit for unprivileged users
  scripts/kvm/kvm_stat: Read event values as u64
  scripts/kvm/kvm_stat: Cleanup and pre-init perf_event_attr
  scripts/kvm/kvm_stat: Fix output formatting
  scripts/kvm/kvm_stat: Make tui function a class
  scripts/kvm/kvm_stat: Remove unneeded X86_EXIT_REASONS
  scripts/kvm/kvm_stat: Group arch specific data
  scripts/kvm/kvm_stat: Cleanup of Event class
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-01-26 15:09:13 +00:00
Denis V. Lunev
e5f3e12e84 nbd: add missed aio_context_acquire in nbd_export_new
blk_invalidate_cache() can call qcow2_invalidate_cache which performs
IO inside.

Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1453273940-15382-3-git-send-email-den@openvz.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-01-26 15:58:14 +01:00
Kevin Wolf
04c01a5c8f block: Rename BDRV_O_INCOMING to BDRV_O_INACTIVE
Instead of covering only the state of images on the migration
destination before the migration is completed, the flag will also cover
the state of images on the migration source after completion. This
common state implies that the image is technically still open, but no
writes will happen and any cached contents will be reloaded from disk if
and when the image leaves this state.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2016-01-20 13:36:23 +01:00
Paolo Bonzini
f1c17521e7 nbd-server: do not exit on failed memory allocation
The amount of memory allocated in nbd_co_receive_request is driven by the
NBD client (possibly a virtual machine).  Parallel I/O can cause the
server to allocate a large amount of memory; check for failures and
return ENOMEM in that case.

Cc: qemu-block@nongnu.org
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-01-15 18:58:02 +01:00
Paolo Bonzini
eb38c3b670 nbd-server: do not check request length except for reads and writes
Only reads and writes need to allocate memory correspondent to the
request length.  Other requests can be sent to the storage without
allocating any memory, and thus any request length is acceptable.

Reported-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Cc: qemu-block@nongnu.org
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-01-15 18:58:02 +01:00
Fam Zheng
1a6245a5b0 nbd-server: Coroutine based negotiation
Create a coroutine in nbd_client_new, so that nbd_send_negotiate doesn't
need qemu_set_block().

Handlers need to be set temporarily for csock fd in case the coroutine
yields during I/O.

With this, if the other end disappears in the middle of the negotiation,
we don't block the whole event loop.

To make the code clearer, unify all function names that belong to
negotiate, so they are less likely to be misused. This is important
because we rely on negotiation staying in main loop, as commented in
nbd_negotiate_read/write().

Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <1452760863-25350-4-git-send-email-famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-01-15 18:58:02 +01:00
Fam Zheng
798bfe0006 nbd: Split nbd.c
We have NBD server code and client code, all mixed in a file. Now split
them into separate files under nbd/, and update MAINTAINERS.

filter_nbd for iotest 083 is updated to keep the log filtered out.

Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <1452760863-25350-3-git-send-email-famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-01-15 18:58:02 +01:00