I'm going to flatten SocketAddress: rename SocketAddress to
SocketAddressLegacy, SocketAddressFlat to SocketAddress, eliminate
SocketAddressLegacy except in external interfaces.
inet_parse() returns a newly allocated InetSocketAddress. Lift the
allocation from inet_parse() into its caller socket_parse() to prepare
for flattening SocketAddress.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1493192202-3184-3-git-send-email-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[Straightforward rebase]
We now have macros in place to make it less verbose to add a scalar
to QDict and QList, so use them.
Patch created mechanically via:
spatch --sp-file scripts/coccinelle/qobject.cocci \
--macro-file scripts/cocci-macro-file.h --dir . --in-place
then touched up manually to fix a couple of '?:' back to original
spacing, as well as avoiding a long line in monitor.c.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20170427215821.19397-7-eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
SocketAddress is a simple union, and simple unions are awkward: they
have their variant members wrapped in a "data" object on the wire, and
require additional indirections in C. I intend to limit its use to
existing external interfaces, and convert all internal interfaces to
SocketAddressFlat.
BlockdevOptionsNbd is an external interface using SocketAddress. We
already use SocketAddressFlat elsewhere in blockdev-add. Replace it
by SocketAddressFlat while we can (it's new in 2.9) for simplicity and
consistency. For example,
{ "execute": "blockdev-add",
"arguments": { "node-name": "foo", "driver": "nbd",
"server": { "type": "inet",
"data": { "host": "localhost",
"port": "12345" } } } }
becomes
{ "execute": "blockdev-add",
"arguments": { "node-name": "foo", "driver": "nbd",
"server": { "type": "inet",
"host": "localhost", "port": "12345" } } }
Since the internal interfaces still take SocketAddress, this requires
conversion function socket_address_crumple(). It'll go away when I
update the interfaces.
Unfortunately, SocketAddress is also visible in -drive since 2.8:
-drive if=none,driver=nbd,server.type=inet,server.data.host=127.0.0.1,server.data.port=12345
Nobody should be using it, as it's fairly new and has never been
documented, so adding still more compatibility gunk to keep it working
isn't worth the trouble. You now have to use
-drive if=none,driver=nbd,server.type=inet,server.host=127.0.0.1,server.port=12345
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-id: 1490895797-29094-9-git-send-email-armbru@redhat.com
[mreitz: Change iotest 147 accordingly]
Because of this interface change, iotest 147 has to be adapted.
Unfortunately, we cannot just flatten all of the addresses because
nbd-server-start still takes a plain SocketAddress. Therefore, we need
both and this is most easily achieved by writing the SocketAddress into
the code and flattening it where necessary.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170330221243.17333-1-mreitz@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
-blockdev and blockdev_add convert their arguments via QObject to
BlockdevOptions for qmp_blockdev_add(), which converts them back to
QObject, then to a flattened QDict. The QDict's members are typed
according to the QAPI schema.
-drive converts its argument via QemuOpts to a (flat) QDict. This
QDict's members are all QString.
Thus, the QType of a flat QDict member depends on whether it comes
from -drive or -blockdev/blockdev_add, except when the QAPI type maps
to QString, which is the case for 'str' and enumeration types.
The block layer core extracts generic configuration from the flat
QDict, and the block driver extracts driver-specific configuration.
Both commonly do so by converting (parts of) the flat QDict to
QemuOpts, which turns all values into strings. Not exactly elegant,
but correct.
However, A few places access the flat QDict directly:
* Most of them access members that are always QString. Correct.
* bdrv_open_inherit() accesses a boolean, carefully. Correct.
* nfs_config() uses a QObject input visitor. Correct only because the
visited type contains nothing but QStrings.
* nbd_config() and ssh_config() use a QObject input visitor, and the
visited types contain non-QStrings: InetSocketAddress members
@numeric, @to, @ipv4, @ipv6. -drive works as long as you don't try
to use them (they're all optional). @to is ignored anyway.
Reproducer:
-drive driver=ssh,server.host=h,server.port=22,server.ipv4,path=p
-drive driver=nbd,server.type=inet,server.data.host=h,server.data.port=22,server.data.ipv4
both fail with "Invalid parameter type for 'data.ipv4', expected: boolean"
Add suitable comments to all these places. Mark the buggy ones FIXME.
"Fortunately", -drive's driver-specific options are entirely
undocumented.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-id: 1490895797-29094-5-git-send-email-armbru@redhat.com
[mreitz: Fixed two typos]
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Certain features make sense only with certain address families. For
instance, passing file descriptors requires AF_UNIX. Testing
SocketAddress's saddr->type == SOCKET_ADDRESS_KIND_UNIX is obvious,
but problematic: it can't recognize AF_UNIX when type ==
SOCKET_ADDRESS_KIND_FD.
Mark such tests of saddr->type TODO. We may want to check the address
family with getsockname() there.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1490895797-29094-2-git-send-email-armbru@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
When TCP connection fails between nbd server and client,
the local var, sioc, memory leak.
This patch fixes the memory leak.
Signed-off-by: yaolujing <yaolujing@huawei.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1491005709-29989-1-git-send-email-yaolujing@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20170327123223.1199-1-stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The split between tests/test-qobject-input-visitor.c and
tests/test-qobject-input-strict.c now makes less sense than ever. The
next commit will take care of that.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1488544368-30622-20-git-send-email-armbru@redhat.com>
After a visit of a complex QAPI type FOO
ov = qobject_output_visitor_new(&foo);
visit_type_FOO(ov, NULL, expr, &error_abort);
visit_complete(ov, &foo);
we can safely assume qobject_type(foo) is QTYPE_QDICT. We do in many
places, but occasionally assert qobject_type(obj) == QTYPE_QDICT.
Don't. The appropriate place to check such fundamental properties of
QAPI visitors is the test suite.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1487363905-9480-15-git-send-email-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
This patch frees the leaked visitor in nbd_refresh_filename() and uses
visit_free() to fix it. The leak was introduced by the commit 491d6c7.
Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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 a hole.
The generic block code takes care of falling back to the obvious
write of lots of zeroes if we return -ENOTSUP because the server
does not have WRITE_ZEROES.
Ideally, since NBD_CMD_WRITE_ZEROES does not involve any data
over the wire, we want to support transactions that are much
larger than the normal 32M limit imposed on NBD_CMD_WRITE. But
the server may still have a limit smaller than UINT_MAX, so
until experimental NBD protocol additions for advertising various
command sizes is finalized (see [1], [2]), for now we just stick to
the same limits as normal writes.
[1] https://github.com/yoe/nbd/blob/extension-info/doc/proto.md
[2] https://sourceforge.net/p/nbd/mailman/message/35081223/
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-17-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
It's better to use consistent capitalization of the namespace
used for NBD functions; we have more instances of NBD* than
Nbd*.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-5-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-----BEGIN PGP SIGNATURE-----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=gsxL
-----END PGP SIGNATURE-----
Merge remote-tracking branch 'remotes/berrange/tags/pull-qio-2016-10-27-1' into staging
Merge qio 2016/10/27 v1
# gpg: Signature made Thu 27 Oct 2016 13:54:03 BST
# gpg: using RSA key 0xBE86EBB415104FDF
# gpg: Good signature from "Daniel P. Berrange <dan@berrange.com>"
# gpg: aka "Daniel P. Berrange <berrange@redhat.com>"
# Primary key fingerprint: DAF3 A6FD B26B 6291 2D0E 8E3F BE86 EBB4 1510 4FDF
* remotes/berrange/tags/pull-qio-2016-10-27-1:
main: set names for main loop sources created
vnc: set name for all I/O channels created
migration: set name for all I/O channels created
char: set name for all I/O channels created
nbd: set name for all I/O channels created
io: add ability to set a name for IO channels
io: Add a QIOChannelSocket cleanup test
io: set LISTEN flag explicitly for listen sockets
io: Introduce a qio_channel_set_feature() helper
io: Use qio_channel_has_feature() where applicable
io: Fix double shift usages on QIOChannel features
Conflicts:
qemu-char.c
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Drop the use of legacy options in favor of the SocketAddress
representation, even for internal use (i.e. for storing the result of
the filename parsing).
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Add a new option "server" to the NBD block driver which accepts a
SocketAddress.
"path", "host" and "port" are still supported as legacy options and are
mapped to their corresponding SocketAddress representation.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Right now, we have four possible options that conflict with specifying
an NBD filename, and a future patch will add another one ("address").
This future option is a nested QDict that is flattened at this point,
requiring us to test each option whether its key has an "address."
prefix. Therefore, we will then need to iterate through all options
(including the "export" option which was not covered so far).
Adding this iteration logic now will simplify adding the new option
later. A nice side effect is that the user will not receive a long list
of five options which are not supposed to be specified with a filename,
but we can actually print the problematic option.
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Instead of inlining this nice macro (i.e. resorting to
qdict_put_obj(..., QOBJECT(...))), use it.
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Instead of not emitting the port in nbd_refresh_filename(), just set it
to the default if the user did not specify it. This makes the logic a
bit simpler.
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Currently, a port that is passed along with a UNIX socket path is
silently ignored. That is not exactly ideal, it should be an error
instead.
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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>
Store the runtime option values in the BDRVNBDState so they can later be
used in nbd_refresh_filename() without having to directly access the
options QDict which may contain values of non-string types.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Using QemuOpts will prevent qemu from crashing if the input options have
not been validated (which is the case when they are specified on the
command line or in a json: filename) and some have the wrong type.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The NBD protocol doesn't have any notion of sectors, so it is
a fairly easy conversion to use byte-based read and write.
Signed-off-by: Eric Blake <eblake@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1468624988-423-19-git-send-email-eblake@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Another step towards killing off sector-based block APIs.
While at it, call directly into nbd-client.c instead of having
a pointless trivial wrapper in nbd.c.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1468624988-423-14-git-send-email-eblake@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Now that the block layer will honor max_transfer, we can simplify
our code to rely on that guarantee.
The readv code can call directly into nbd-client, just as the
writev code has done since commit 52a4650.
Interestingly enough, while qemu-io 'w 0 40m' splits into a 32M
and 8M transaction, 'w -z 0 40m' splits into two 16M and an 8M,
because the block layer caps the bounce buffer for writing zeroes
at 16M. When we later introduce support for NBD_CMD_WRITE_ZEROES,
we can get a full 32M zero write (or larger, if the client and
server negotiate that write zeroes can use a larger size than
ordinary writes).
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: 1468607524-19021-5-git-send-email-eblake@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Sector-based limits are awkward to think about; in our on-going
quest to move to byte-based interfaces, convert max_discard and
discard_alignment. Rename them, using 'pdiscard' as an aid to
track which remaining discard interfaces need conversion, and so
that the compiler will help us catch the change in semantics
across any rebased code. The BlockLimits type is now completely
byte-based; and in iscsi.c, sector_limits_lun2qemu() is no
longer needed.
pdiscard_alignment is made unsigned (we use power-of-2 alignments
as bitmasks, where unsigned is easier to think about) while
leaving max_pdiscard signed (since we still have an 'int'
interface); this is comparable to what commit cf081fc did for
write zeroes limits. We may later want to make everything an
unsigned 64-bit limit - but that requires a bigger code audit.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Sector-based limits are awkward to think about; in our on-going
quest to move to byte-based interfaces, convert max_transfer_length
and opt_transfer_length. Rename them (dropping the _length suffix)
so that the compiler will help us catch the change in semantics
across any rebased code, and improve the documentation. Use unsigned
values, so that we don't have to worry about negative values and
so that bit-twiddling is easier; however, we are still constrained
by 2^31 of signed int in most APIs.
When a value comes from an external source (iscsi and raw-posix),
sanitize the results to ensure that opt_transfer is a power of 2.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
We were basing the advertisement of maximum discard and transfer
length off of UINT32_MAX, but since the rest of the block layer
has signed int limits on a transaction, nothing could ever reach
that maximum, and we risk overflowing an int once things are
converted to byte-based rather than sector-based limits. What's
more, we DO have a much smaller limit: both the current kernel
and qemu-nbd have a hard limit of 32M on a read or write
transaction, and while they may also permit up to a full 32 bits
on a discard transaction, the upstream NBD protocol is proposing
wording that without any explicit advertisement otherwise,
clients should limit ALL requests to the same limits as read and
write, even though the other requests do not actually require as
many bytes across the wire. So the better limit to tell the
block layer is 32M for both values.
Behavior doesn't actually change with this patch (the block layer
is currently ignoring the max_transfer advertisements); but when
that problem is fixed in a later series, this patch will prevent
the exposure of a latent bug.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Now that the block layer honors per-bds FUA support, we don't
have to duplicate the fallback flush at the NBD layer. The
static function nbd_co_writev_flags() is no longer needed, and
the driver can just directly use nbd_client_co_writev().
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Pre-patch, .supported_write_flags lives at the driver level, which
means we are blindly declaring that all block devices using a
given driver will either equally support FUA, or that we need a
fallback at the block layer. But there are drivers where FUA
support is a per-block decision: the NBD block driver is dependent
on the remote server advertising NBD_FLAG_SEND_FUA (and has
fallback code to duplicate the flush that the block layer would do
if NBD had not set .supported_write_flags); and the iscsi block
driver is dependent on the mode sense bits advertised by the
underlying device (and is currently silently ignoring FUA requests
if the underlying device does not support FUA).
The fix is to make supported flags as a per-BDS option, set during
.bdrv_open(). This patch moves the variable and fixes NBD and iscsi
to set it only conditionally; later patches will then further
simplify the NBD driver to quit duplicating work done at the block
layer, as well as tackle the fact that SCSI does not support FUA
semantics on WRITESAME(10/16) but only on WRITE(10/16).
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This is a function that simply calls into the block driver for doing a
write, providing the byte granularity interface we want to eventually
have everywhere, and using whatever interface that driver supports.
This one is a bit more interesting than the version for reads: It adds
support for .bdrv_co_writev_flags() everywhere, so that drivers
implementing this function can drop .bdrv_co_writev() now.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
The NBD server already used to send a FUA flag when the writethrough
mode was set. This code was a remnant from the times where protocol
drivers actually had to implement writethrough modes. Since nowadays the
block layer sends flushes in writethrough mode and non-root nodes are
always writeback, this was mostly dead code - only mostly because if NBD
was configured to be used without a format, we sent _both_ FUA and an
explicit flush afterwards, which makes the code not technically dead,
but useless overhead.
This patch changes the code so that the block layer's FUA flag is
recognised and translated into a NBD FUA flag. The additional flush is
avoided now.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Move declarations out of qemu-common.h for functions declared in
utils/ files: e.g. include/qemu/path.h for utils/path.c.
Move inline functions out of qemu-common.h and into new files (e.g.
include/qemu/bcd.h)
Signed-off-by: Veronia Bahaa <veroniabahaa@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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>
Simple unions were carrying a special case that hid their 'data'
QMP member from the resulting C struct, via the hack method
QAPISchemaObjectTypeVariant.simple_union_type(). But by using
the work we started by unboxing flat union and alternate
branches, coupled with the ability to visit the members of an
implicit type, we can now expose the simple union's implicit
type in qapi-types.h:
| struct q_obj_ImageInfoSpecificQCow2_wrapper {
| ImageInfoSpecificQCow2 *data;
| };
|
| struct q_obj_ImageInfoSpecificVmdk_wrapper {
| ImageInfoSpecificVmdk *data;
| };
...
| struct ImageInfoSpecific {
| ImageInfoSpecificKind type;
| union { /* union tag is @type */
| void *data;
|- ImageInfoSpecificQCow2 *qcow2;
|- ImageInfoSpecificVmdk *vmdk;
|+ q_obj_ImageInfoSpecificQCow2_wrapper qcow2;
|+ q_obj_ImageInfoSpecificVmdk_wrapper vmdk;
| } u;
| };
Doing this removes asymmetry between QAPI's QMP side and its
C side (both sides now expose 'data'), and means that the
treatment of a simple union as sugar for a flat union is now
equivalent in both languages (previously the two approaches used
a different layer of dereferencing, where the simple union could
be converted to a flat union with equivalent C layout but
different {} on the wire, or to an equivalent QMP wire form
but with different C representation). Using the implicit type
also lets us get rid of the simple_union_type() hack.
Of course, now all clients of simple unions have to adjust from
using su->u.member to using su->u.member.data; while this touches
a number of files in the tree, some earlier cleanup patches
helped minimize the change to the initialization of a temporary
variable rather than every single member access. The generated
qapi-visit.c code is also affected by the layout change:
|@@ -7393,10 +7393,10 @@ void visit_type_ImageInfoSpecific_member
| }
| switch (obj->type) {
| case IMAGE_INFO_SPECIFIC_KIND_QCOW2:
|- visit_type_ImageInfoSpecificQCow2(v, "data", &obj->u.qcow2, &err);
|+ visit_type_q_obj_ImageInfoSpecificQCow2_wrapper_members(v, &obj->u.qcow2, &err);
| break;
| case IMAGE_INFO_SPECIFIC_KIND_VMDK:
|- visit_type_ImageInfoSpecificVmdk(v, "data", &obj->u.vmdk, &err);
|+ visit_type_q_obj_ImageInfoSpecificVmdk_wrapper_members(v, &obj->u.vmdk, &err);
| break;
| default:
| abort();
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1458254921-17042-13-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
An upcoming patch will alter how simple unions, like SocketAddress,
are laid out, which will impact all lines of the form 'addr->u.XXX'
(expanding it to the longer 'addr->u.XXX.data'). For better
legibility in that patch, and less need for line wrapping, it's better
to use a temporary variable to reduce the effect of a layout change to
just the variable initializations, rather than every reference within
a SocketAddress. Also, take advantage of some C99 initialization where
it makes sense (simplifying g_new0() to g_new()).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1457021813-10704-7-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
This modifies the NBD driver so that it is possible to request
use of TLS. This is done by providing the 'tls-creds' parameter
with the ID of a previously created QCryptoTLSCreds object.
For example
$QEMU -object tls-creds-x509,id=tls0,endpoint=client,\
dir=/home/berrange/security/qemutls \
-drive driver=nbd,host=localhost,port=9000,tls-creds=tls0
The client will drop the connection if the NBD server does not
provide TLS.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1455129674-17255-15-git-send-email-berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This converts the NBD block driver client to use the QIOChannelSocket
class for initial connection setup. The NbdClientSession struct has
two pointers, one to the master QIOChannelSocket providing the raw
data channel, and one to a QIOChannel which is the current channel
used for I/O. Initially the two point to the same object, but when
TLS support is added, they will point to different objects.
The qemu-img & qemu-io tools now need to use MODULE_INIT_QOM to
ensure the QIOChannel object classes are registered. The qemu-nbd
tool already did this.
In this initial conversion though, all I/O is still actually done
using the raw POSIX sockets APIs.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1455129674-17255-4-git-send-email-berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
In order to decide whether a blkdebug: filename can be produced or a
json: one is necessary, blkdebug checked whether bs->options had more
options than just "config", "x-image" or "image" (the latter including
nested options). That doesn't work well when generic block layer options
are present.
This patch passes an option QDict to the driver that contains only
driver-specific options, i.e. the options for the general block layer as
well as child nodes are already filtered out. Works much better this
way.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
We have two issues with our qapi union layout:
1) Even though the QMP wire format spells the tag 'type', the
C code spells it 'kind', requiring some hacks in the generator.
2) The C struct uses an anonymous union, which places all tag
values in the same namespace as all non-variant members. This
leads to spurious collisions if a tag value matches a non-variant
member's name.
Make the conversion to the new layout for block-related code.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1445898903-12082-16-git-send-email-eblake@redhat.com>
[Commit message tweaked slightly]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
The nbd block driver currently uses a QemuOpts object
when setting up sockets. Switch it over to use the
QAPI SocketAddress object instead.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1442411543-28513-2-git-send-email-berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
unix_connect_opts() and inet_connect_opts() do not necessarily set errno
(if at all); therefore, nbd_establish_connection() should not literally
return -errno on error.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <1424887718-10800-4-git-send-email-mreitz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Return the Error object instead of reporting it with
qerror_report_err().
Change callers that assume the function can't fail to pass
&error_abort, so that should the assumption ever break, it'll break
noisily.
Turns out all callers outside its unit test assume that. We could
drop the Error ** argument, but that would make the interface less
regular, so don't.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Before this patch, the "opaque" pointer in an NBD BDS points to a
BDRVNBDState, which contains an NbdClientSession object, which in turn
contains a pointer to the BDS. This pointer may become invalid due to
bdrv_swap(), so drop it, and instead pass the BDS directly to the
nbd-client.c functions which then retrieve the NbdClientSession object
from there.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1423256778-3340-2-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
nbd_co_discard calls nbd_client_session_co_discard which uses uint32_t
as the length in bytes of the data to discard due to the following
definition:
struct nbd_request {
uint32_t magic;
uint32_t type;
uint64_t handle;
uint64_t from;
uint32_t len; <-- the length of data to be discarded, in bytes
} QEMU_PACKED;
Thus we should limit bl_max_discard to UINT32_MAX >> BDRV_SECTOR_BITS to
avoid overflow.
NBD read/write code uses the same structure for transfers. Fix
max_transfer_length accordingly.
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Peter Lieven <pl@kamp.de>
CC: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This patch makes use of the Error object for nbd_receive_negotiate() so
that errors during negotiation look nicer.
Furthermore, this patch adds an additional error message if the received
magic was wrong, but would be correct for the other protocol version,
respectively: So if an export name was specified, but the NBD server
magic corresponds to an old handshake, this condition is explicitly
signaled to the user, and vice versa.
As these messages are now part of the "Could not open image" error
message, additional filtering has to be employed in iotest 083, which
this patch does as well.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Export names may be used with nbd+unix, too, fix nbd_refresh_filename()
accordingly. Also, for nbd+tcp, the documented path schema is
"nbd://host[:port]/export", so use it. Furthermore, as can be seen from
that schema, the port is optional.
That makes six single cases for how the filename can be formatted; it is
not easy to generalize these cases without the resulting statement being
completely unreadable, thus there is simply one snprintf() per case.
Finally, taking the options from BDRVNBDState::socket_opts is wrong,
because those will not contain the export name. Just use
BlockDriverState::options instead.
Reported-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Drop the assumption that we're using the main AioContext. Convert
qemu_aio_set_fd_handler() calls to aio_set_fd_handler().
The .bdrv_detach/attach_aio_context() interfaces also need to be
implemented to move the socket fd handler from the old to the new
AioContext.
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Using error_is_set(errp) to check whether a function call failed is
fragile: it breaks when errp is null. Check perfectly suitable return
values instead when possible. errp can't be null there now, but this
is more robust and more obviously correct
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Before:
$ ./qemu-io-old
qemu-io-old> open -r -o file.driver=nbd
one of path and host must be specified.
qemu-io-old: can't open device (null): Could not open image: Invalid argument
$ ./qemu-io-old
qemu-io-old> open -r -o file.driver=nbd,file.host=foo,file.path=bar
path and host may not be used at the same time.
qemu-io-old: can't open device (null): Could not open image: Invalid argument
After:
$ ./qemu-io
qemu-io> open -r -o file.driver=nbd
qemu-io: can't open device (null): one of path and host must be specified.
$ ./qemu-io
qemu-io> open -r -o file.driver=nbd,file.host=foo,file.path=bar
qemu-io: can't open device (null): path and host may not be used at the same time.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Before:
$ qemu-io-old
qemu-io-old> open -r -o file.driver=nbd
qemu-io-old: can't open device (null): Could not open image: Invalid argument
$ ./qemu-io-old
qemu-io-old> open -r -o file.driver=nbd,file.host=foo,file.path=bar
path and host may not be used at the same time.
qemu-io-old: can't open device (null): Could not open image: Invalid argument
After:
$ ./qemu-io
qemu-io> open -r -o file.driver=nbd
one of path and host must be specified.
qemu-io: can't open device (null): Could not open image: Invalid argument
$ ./qemu-io
qemu-io> open -r -o file.driver=nbd,file.host=foo,file.path=bar
path and host may not be used at the same time.
qemu-io: can't open device (null): Could not open image: Invalid argument
Next patch will fix the error propagation.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
error_is_set(&var) is the same as var != NULL, but it takes
whole-program analysis to figure that out. Unnecessarily hard for
optimizers, static checkers, and human readers. Dumb it down to
obvious.
Gets rid of several dozen Coverity false positives.
Note that the obvious form is already used in many places.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
This is a boiler-plate _nofail variant of qemu_opts_create. Remove and
use error_abort in call sites.
null/0 arguments needs to be added for the id and fail_if_exists fields
in affected callsites due to argument inconsistency between the normal and
no_fail variants.
Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
There is no need to keep the export name around, and it seems a better
fit as an argument in the init() call.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Add an Error ** parameter to BlockDriver.bdrv_open and
BlockDriver.bdrv_file_open to allow more specific error messages.
Signed-off-by: Max Reitz <mreitz@redhat.com>
The .io_flush() handler no longer exists and has no users. Drop the
io_flush argument to aio_set_fd_handler() and related functions.
The AioFlushEventNotifierHandler and AioFlushHandler typedefs are no
longer used and are dropped too.
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
.io_flush() is no longer called so drop nbd_have_request(). We cannot
drop in_flight since it is still used by other block/nbd.c code.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Otherwise they would get passed to getaddrinfo and fail with:
address resolution failed for [::1]🔢 Name or service not known
(Broken by commit v1.4.0-736-gf17c90b)
Signed-off-by: Ján Tomko <jtomko@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
# By Kevin Wolf (16) and Stefan Hajnoczi (4)
# Via Kevin Wolf
* kwolf/for-anthony:
qemu-iotests: add 053 unaligned compressed image size test
block: Allow overriding backing.file.filename
block: Remove filename parameter from .bdrv_file_open()
vvfat: Use bdrv_open options instead of filename
sheepdog: Use bdrv_open options instead of filename
rbd: Use bdrv_open options instead of filename
iscsi: Use bdrv_open options instead of filename
gluster: Use bdrv_open options instead of filename
curl: Use bdrv_open options instead of filename
blkverify: Use bdrv_open options instead of filename
blkdebug: Use bdrv_open options instead of filename
raw-win32: Use bdrv_open options instead of filename
raw-posix: Use bdrv_open options instead of filename
block: Enable filename option
block: Add driver-specific options for backing files
block: Fail gracefully when using a format driver on protocol level
qemu-iotests: Fix _filter_qemu
qemu-img: do not zero-pad the compressed write buffer
qcow: allow sub-cluster compressed write to last cluster
qcow2: allow sub-cluster compressed write to last cluster
Message-id: 1366630294-18984-1-git-send-email-kwolf@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Disable the Nagle algorithm to reduce latency. Note this means we must
also use TCP_CORK when sending header followed by payload to avoid
fragmenting lots of little packets. The previous patch took care of
that.
Suggested-by: Nick Thomas <nick@bytemark.co.uk>
Tested-by: Nick Thomas <nick@bytemark.co.uk>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Use TCP_CORK to defer packet transmission until both the header and the
payload have been written.
Suggested-by: Nick Thomas <nick@bytemark.co.uk>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The fcntl(fd, F_SETFL, O_NONBLOCK) flag is not specific to sockets.
Rename to qemu_set_nonblock() just like qemu_set_cloexec().
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
A file name may only specified if no host or socket path is specified.
The latter two may not appear at the same time either.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
The URL method already takes care to apply the default port when none is
specfied. Directly specifying driver-specific options required the port
number until now. Allow leaving it out and apply the default.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
If a driver needs structured data and not just a string, it can provide
a .bdrv_parse_filename callback now that parses the command line string
into separate options. Keeping this separate from .bdrv_open_filename
ensures that the preferred way of directly specifying the options always
works as well if parsing the string works.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
The existing parsers for the file name now parse everything into the
bdrv_open() options QDict. Instead of using these parsers, you can now
directly specify the options on the command line, like this:
qemu-system-x86_64 -drive file=nbd:,file.port=1234,file.host=::1
Clearly the file=... part could use further improvement, but it's a
start.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
The NBD block supports an URL syntax, for which a URL parser returns
separate hostname and port fields. It also supports the traditional qemu
syntax encoded in a filename. Until now, after parsing the URL to get
each piece of information, a new string is built to be fed to socket
functions.
Instead of building a string in the URL case that is immediately parsed
again, parse the string in both cases and use the QemuOpts interface to
qemu-sockets.c.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
The URI syntax is consistent with the Gluster syntax. Export names
are specified in the path, preceded by one or more (otherwise unused)
slashes.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The same as for non-coroutine versions in previous
patches: rename arguments to be more obvious, change
type of arguments from int to size_t where appropriate,
and use common code for send and receive paths (with
one extra argument) since these are exactly the same.
Use common iov_send_recv() directly.
qemu_co_sendv(), qemu_co_recvv(), and qemu_co_recv()
are now trivial #define's merely adding one extra arg.
qemu_co_sendv() and qemu_co_recvv() callers are
converted to different argument order and extra
`iov_cnt' argument.
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
s->sock is assigned only afterwards, so we're really registering an
aio_fd_handler for file descriptor 0 here. Not exactly what we intended.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* kwolf/for-anthony: (38 commits)
qemu-iotests: Fix test 031 for qcow2 v3 support
qemu-iotests: Add -o and make v3 the default for qcow2
qcow2: Zero write support
qemu-iotests: Test backing file COW with zero clusters
qemu-iotests: add a simple test for write_zeroes
qcow2: Support for feature table header extension
qcow2: Support reading zero clusters
qcow2: Version 3 images
qcow2: Ignore reserved bits in check_refcounts
qcow2: Ignore reserved bits in refcount table entries
qcow2: Simplify count_cow_clusters
qcow2: Refactor qcow2_free_any_clusters
qcow2: Ignore reserved bits in L1/L2 entries
qcow2: Fail write_compressed when overwriting data
qcow2: Ignore reserved bits in count_contiguous_clusters()
qcow2: Ignore reserved bits in get_cluster_offset
qcow2: Save disk size in snapshot header
Specification for qcow2 version 3
qcow2: Fix refcount block allocation during qcow2_alloc_cluster_at()
iotests: Resolve test failures caused by hostname
...
Right now, nbd_wr_sync will hang if no data at all is available on the
socket and the other side is not going to provide any. Relax this by
making it loop only for writes or partial reads. This fixes a race
where one thread is executing qemu_aio_wait() and another is executing
main_loop_wait(). Then, the select() call in main_loop_wait() can return
stale data and call the "readable" callback with no data in the socket.
Reported-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In the next patch we need to look at the return code of nbd_wr_sync.
To avoid percolating the socket_error() ugliness all around, let's
handle errors by returning negative errno values.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Allow sending up to 16 requests, and drive the replies to the coroutine
that did the request. The code is written to be exactly the same as
before this patch when MAX_NBD_REQUESTS == 1 (modulo the extra mutex
and state).
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
qemu-nbd has a limit of slightly less than 1M per request. Work
around this in the nbd block driver.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Double semicolons should be single.
Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
This does the first part of the conversion to coroutines, by
wrapping bdrv_write implementations to take the mutex.
Drivers that implement bdrv_write rather than bdrv_co_writev can
then benefit from asynchronous operation (at least if the underlying
protocol supports it, which is not the case for raw-win32), even
though they still operate with a bounce buffer.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This does the first part of the conversion to coroutines, by
wrapping bdrv_read implementations to take the mutex.
Drivers that implement bdrv_read rather than bdrv_co_readv can
then benefit from asynchronous operation (at least if the underlying
protocol supports it, which is not the case for raw-win32), even
though they still operate with a bounce buffer.
raw-win32 does not need the lock, because it cannot yield.
nbd also doesn't probably, but better be safe.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The big conversion of bdrv_read/write to coroutines caused the two
homonymous callbacks in BlockDriver to become reentrant. It goes
like this:
1) bdrv_read is now called in a coroutine, and calls bdrv_read or
bdrv_pread.
2) the nested bdrv_read goes through the fast path in bdrv_rw_co_entry;
3) in the common case when the protocol is file, bdrv_co_do_readv calls
bdrv_co_readv_em (and from here goes to bdrv_co_io_em), which yields
until the AIO operation is complete;
4) if bdrv_read had been called from a bottom half, the main loop
is free to iterate again: a device model or another bottom half
can then come and call bdrv_read again.
This applies to all four of read/write/flush/discard. It would also
apply to is_allocated, but it is not used from within coroutines:
besides qemu-img.c and qemu-io.c, which operate synchronously, the
only user is the monitor. Copy-on-read will introduce a use in the
block layer, and will require converting it.
The solution is "simply" to convert all drivers to coroutines! We
just need to add a CoMutex that is taken around affected operations.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
nbd supports writing flags in bytes 24...27 of the header,
and uses that for the read-only flag. Add support for it
in qemu-nbd.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
