Commit Graph

88207 Commits

Author SHA1 Message Date
John Snow 176c549072 python/qmp: add fuse command to 'qom' tools
The 'fuse' command will be unavailable if 'fusepy' is not installed. It
will simply not load and subsequently be unavailable as a subcommand.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20210603003719.1321369-20-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-18 16:10:06 -04:00
John Snow c89b38cd0a scripts/qom-fuse: add redirection shim to python/qemu/qmp/qom-fuse.py
By leaving the script absent for a commit, git-blame travels to the new
file instead of staying on the shim.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20210603003719.1321369-19-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-18 16:10:06 -04:00
John Snow 173d185de9 scripts/qom-fuse: move to python/qemu/qmp/qom_fuse.py
Move qom-fuse over to the python package now that it passes the
linter. Update the import paradigms so that it continues to pass in the
context of the Python package.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 20210603003719.1321369-18-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-18 16:10:06 -04:00
John Snow c63f3b0b29 python: add optional FUSE dependencies
In preparation for moving qom-fuse over to the python package, we need
some new dependencies to support it.

Add an optional 'fusepy' dependency that users of the package can opt
into with e.g. "pip install qemu[fuse]" which installs the requirements
necessary to obtain the additional functionality.

Add the same fusepy dependency to the 'devel' extras group --
unfortunately I do not see a way for optional groups to imply other
optional groups at present, so the dependency is repeated. The
development group needs to include the full set of dependencies for the
purpose of static analysis of all features offered by this library.

Lastly, add the [fuse] extras group to tox's configuration as a
workaround so that if a stale tox environment is found when running
`make check-tox`, tox will know to rebuild its environments.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 20210603003719.1321369-17-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-18 16:10:06 -04:00
John Snow 30ec845c59 scripts/qom-fuse: add static type hints
Because fusepy does not have type hints, add some targeted warning
suppressions.

Namely, we need to allow subclassing something of an unknown type (in
qom_fuse.py), and we need to allow missing imports (recorded against
fuse itself) because mypy will be unable to import fusepy (even when
installed) as it has no types nor type stubs available.

Note: Until now, it was possible to run invocations like 'mypy qemu/'
from ./python and have that work. However, these targeted suppressions
require that you run 'mypy -p qemu/' instead. The correct, canonical
invocation is recorded in ./python/tests/mypy.sh and all of the various
CI invocations always use this correct form.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 20210603003719.1321369-16-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-18 16:10:06 -04:00
John Snow 2cea713462 scripts/qom-fuse: ensure QOMFuse.read always returns bytes
- Use FuseOSError to signal ENOENT instead of returning it
- Wrap qom-get in str(), as we don't always know its type
- The empty return should be b'', not ''.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20210603003719.1321369-15-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-18 16:10:06 -04:00
John Snow 9ec8a38694 scripts/qom-fuse: use QOMCommand.qom_list()
the qom_list method provides a type-safe object that's easier to type
check, so switch to using it.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20210603003719.1321369-14-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-18 16:10:06 -04:00
John Snow 2aa101799a scripts/qom-fuse: Convert to QOMCommand
Move qom-fuse onto the QOMCommand base established in
python/qemu/qmp/qom_common.py. The interface doesn't change
incompatibly, "qom-fuse mountpoint" still works as an invocation, and
QMP_SOCKET is still used as the environment variable.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 20210603003719.1321369-13-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-18 16:10:06 -04:00
John Snow 187be27c7b scripts/qom-fuse: Add docstrings
The methods inherited from fuse don't need docstrings; that's up to
fusepy to handle.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 20210603003719.1321369-12-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-18 16:10:06 -04:00
John Snow 7552823a36 scripts/qom-fuse: Apply pylint rules
- Catch specific exceptions from QMP
- Reraise errors with explicit context
- method parameters should match parent's names

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20210603003719.1321369-11-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-18 16:10:06 -04:00
John Snow d229f1c83d python: Add 'fh' to known-good variable names
fd and fh are fine: we often use these for "file descriptor" or "file
handle" accordingly. It is rarely the case that you need to enforce a
more semantically meaningful name beyond "This is the file we are using
right now."

While we're here: add comments for all of the non-standard pylint
names. (And the underscore.)

Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 20210603003719.1321369-10-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-18 16:10:06 -04:00
John Snow 26c1ccadc4 scripts/qom-fuse: apply flake8 rules
flake8 still has one warning because of the sys.path hack, but that will
be going away by the end of this patch series.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20210603003719.1321369-9-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-18 16:10:06 -04:00
John Snow c6b7eae9b6 scripts/qom-fuse: apply isort rules
Hint: you can use symlinks to create qom_fuse.py in python/qemu/qmp/ and
point to scripts/qom-fuse to apply the standard linting rules to this
script.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20210603003719.1321369-8-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-18 16:10:06 -04:00
John Snow 908ff4b29f scripts/qmp: redirect qom-xxx scripts to python/qemu/qmp/
Redirect to the new qom scripts. These forwarders can be deleted
eventually when there has been more time for the dust on the Python
packaging to settle and people understand how to find these commands.

Note: You can run these by setting $PYTHONPATH in your shell and then
running "python3 -m qemu.qmp.qom", or you can install the qemu namespace
package and use the "qom" or "qom-set" scripts.

I've written how to install the package elsewhere, but for the sake of
git-blame, cd to ./python, and then do:

- pip3 install [--user] [-e] .

--user will install to your local user install (will not work inside of
  a venv), omitting this flag installs to your system-wide packages
  (outside of a venv) or to your current virtual environment (inside the
  venv).

  When installing to a venv or to your system-wide packages, "qom"
  should be in your $PATH already. If you do a user install, you may
  need to add ~/.local/bin to your $PATH if you haven't already.

-e installs in editable mode: the installed package is effectively just
 a symlink to this folder; so changes to your git working tree are
 reflected in the installed package.

Note: installing these packages to an environment outside a venv can be
dangerous: Many QEMU scripts will begin to prefer the installed version
instead of the version directly in the tree. Use with caution. editable
mode is recommended when working outside of a venv.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20210603003719.1321369-7-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-18 16:10:06 -04:00
John Snow 7c4c595f13 python/qmp: add qom script entry points
Add the 'qom', 'qom-set', 'qom-get', 'qom-list', and 'qom-tree' scripts
to the qemu.qmp package. When you install this package, these scripts
will become available on your command line.

(e.g. when inside of a venv, `cd python && pip install .` will add
'qom', 'qom-set', etc to your $PATH.)

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20210603003719.1321369-6-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-18 16:10:06 -04:00
John Snow c750c02891 python/qmp: Add qom script rewrites
Inspired by qom-set, qom-get, qom-tree and qom-list; combine all four of
those scripts into a single script.

A later addition of qom-fuse as an 'extension' necessitates that some
common features are split out and shared between them.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 20210603003719.1321369-5-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-18 16:10:06 -04:00
John Snow 587adaca55 python/qmp: add parse_address classmethod
This takes the place of qmp-shell's __get_address function. It also
allows other utilities to share the same parser and syntax for
specifying QMP locations.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 20210603003719.1321369-4-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-18 16:10:06 -04:00
John Snow 5d15c9b875 python/qmp: Fix type of SocketAddrT
In porting the qom tools, qmp-shell, etc; it becomes evident that this
type is wrong.

This is an integer, not a string. We didn't catch this before because
none of QEMUMonitorProtocol's *users* happen to be checked, and the
internal logic of this class is otherwise self-consistent. Additionally,
mypy was not introspecting into the socket() interface to realize we
were passing a bad type for AF_INET. Fixed now.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20210603003719.1321369-3-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-18 16:10:06 -04:00
John Snow 9d0ead63bf python/pipenv: Update Pipfile.lock
In a previous commit, I added tox to the development requirements of the
Python library. I never bothered to add them to the Pipfile, because
they aren't needed there. Here, I sync it anyway in its own commit so
that when we add new packages later that the diffstats will not
confusingly appear to pull in lots of extra packages.

Ideally I could tell Pipenv simply not to install these, but it doesn't
seem to support that, exactly. The alternative is removing Tox from the
development requires, which I'd rather not do.

The other alternative is re-specifying all of the dependencies of
setup.cfg in the Pipfile, which I'd also rather not do.

Picking what feels least-worst here.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 20210603003719.1321369-2-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
2021-06-18 16:10:05 -04:00
Vladimir Sementsov-Ogievskiy bbfb7c2f35 block/nbd: safer transition to receiving request
req->receiving is a flag of request being in one concrete yield point
in nbd_co_do_receive_one_chunk().

Such kind of boolean flag is always better to unset before scheduling
the coroutine, to avoid double scheduling. So, let's be more careful.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-33-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 12:21:22 -05:00
Vladimir Sementsov-Ogievskiy 91e0998f5a block/nbd: add nbd_client_connected() helper
We already have two similar helpers for other state. Let's add another
one for convenience.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-32-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 12:21:22 -05:00
Vladimir Sementsov-Ogievskiy a71d597b98 block/nbd: reuse nbd_co_do_establish_connection() in nbd_open()
The only last step we need to reuse the function is coroutine-wrapper.
nbd_open() may be called from non-coroutine context. So, generate the
wrapper and use it.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-31-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 12:21:22 -05:00
Vladimir Sementsov-Ogievskiy 97cf89259e nbd/client-connection: add option for non-blocking connection attempt
We'll need a possibility of non-blocking nbd_co_establish_connection(),
so that it returns immediately, and it returns success only if a
connections was previously established in background.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-30-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 12:21:22 -05:00
Vladimir Sementsov-Ogievskiy 51edbf537d block/nbd: split nbd_co_do_establish_connection out of nbd_reconnect_attempt
Split out the part that we want to reuse for nbd_open().

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610100802.5888-29-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 12:21:21 -05:00
Vladimir Sementsov-Ogievskiy bb43694872 block-coroutine-wrapper: allow non bdrv_ prefix
We are going to reuse the script to generate a nbd_ function in
further commit. Prepare the script now.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-28-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 12:21:21 -05:00
Vladimir Sementsov-Ogievskiy 43cb34dede nbd/client-connection: return only one io channel
block/nbd doesn't need underlying sioc channel anymore. So, we can
update nbd/client-connection interface to return only one top-most io
channel, which is more straight forward.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-27-vsementsov@virtuozzo.com>
[eblake: squash in Vladimir's fixes for uninit usage caught by clang]
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 12:20:53 -05:00
Vladimir Sementsov-Ogievskiy 95a078ea3e block/nbd: drop BDRVNBDState::sioc
Currently sioc pointer is used just to pass from socket-connection to
nbd negotiation. Drop the field, and use local variables instead. With
next commit we'll update nbd/client-connection.c to behave
appropriately (return only top-most ioc, not two channels).

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-26-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:54 -05:00
Vladimir Sementsov-Ogievskiy c2405af0e4 block/nbd: don't touch s->sioc in nbd_teardown_connection()
Negotiation during reconnect is now done in a thread, and s->sioc is
not available during negotiation. Negotiation in thread will be
cancelled by nbd_client_connection_release() called from
nbd_clear_bdrvstate().  So, we don't need this code chunk anymore.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-25-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:54 -05:00
Vladimir Sementsov-Ogievskiy 6d2b0332d3 block/nbd: use negotiation of NBDClientConnection
Now that we can opt in to negotiation as part of the client connection
thread, use that to simplify connection_co.  This is another step on
the way to moving all reconnect code into NBDClientConnection.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-24-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:54 -05:00
Vladimir Sementsov-Ogievskiy e9ba7788b0 block/nbd: split nbd_handle_updated_info out of nbd_client_handshake()
To be reused in the following patch.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-23-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:54 -05:00
Vladimir Sementsov-Ogievskiy f58b2dfe3e nbd/client-connection: shutdown connection on release
Now, when a thread can do negotiation and retry, it may run relatively
long. We need a mechanism to stop it, when the user is not interested
in a result any more. So, on nbd_client_connection_release() let's
shutdown the socket, and do not retry connection if thread is detached.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610100802.5888-22-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:53 -05:00
Vladimir Sementsov-Ogievskiy e0e67cbe58 nbd/client-connection: implement connection retry
Add an option for a thread to retry connecting until it succeeds. We'll
use nbd/client-connection both for reconnect and for initial connection
in nbd_open(), so we need a possibility to use same NBDClientConnection
instance to connect once in nbd_open() and then use retry semantics for
reconnect.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610100802.5888-21-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: grammar tweak]
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:53 -05:00
Vladimir Sementsov-Ogievskiy 130d49baa5 nbd/client-connection: add possibility of negotiation
Add arguments and logic to support nbd negotiation in the same thread
after successful connection.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610100802.5888-20-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:53 -05:00
Vladimir Sementsov-Ogievskiy e70da5ff64 nbd/client-connection: use QEMU_LOCK_GUARD
We don't update connect_thread_func() to use QEMU_LOCK_GUARD, as it
will get more complex critical sections logic in further commit, where
QEMU_LOCK_GUARD doesn't help.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610100802.5888-19-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:53 -05:00
Vladimir Sementsov-Ogievskiy 5276c87c12 nbd: move connection code from block/nbd to nbd/client-connection
We now have bs-independent connection API, which consists of four
functions:

  nbd_client_connection_new()
  nbd_client_connection_release()
  nbd_co_establish_connection()
  nbd_co_establish_connection_cancel()

Move them to a separate file together with NBDClientConnection
structure which becomes private to the new API.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-18-vsementsov@virtuozzo.com>
[eblake: comment tweaks]
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:53 -05:00
Vladimir Sementsov-Ogievskiy 248d470198 block/nbd: introduce nbd_client_connection_release()
This is a last step of creating bs-independent nbd connection
interface. With next commit we can finally move it to separate file.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610100802.5888-17-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:53 -05:00
Vladimir Sementsov-Ogievskiy f68729747d block/nbd: introduce nbd_client_connection_new()
This is a step of creating bs-independent nbd connection interface.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-16-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:53 -05:00
Vladimir Sementsov-Ogievskiy 90ddc64fb2 block/nbd: rename NBDConnectThread to NBDClientConnection
We are going to move the connection code to its own file, and want
clear names and APIs first.

The structure is shared between user and (possibly) several runs of
connect-thread. So it's wrong to call it "thread". Let's rename to
something more generic.

Appropriately rename connect_thread and thr variables to conn.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-15-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:53 -05:00
Vladimir Sementsov-Ogievskiy c3e7730485 block/nbd: make nbd_co_establish_connection_cancel() bs-independent
nbd_co_establish_connection_cancel() actually needs only pointer to
NBDConnectThread. So, make it clean.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-14-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:53 -05:00
Vladimir Sementsov-Ogievskiy d33833d7af block/nbd: bs-independent interface for nbd_co_establish_connection()
We are going to split connection code to a separate file. Now we are
ready to give nbd_co_establish_connection() clean and bs-independent
interface.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-13-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:53 -05:00
Vladimir Sementsov-Ogievskiy b8e8a3d116 block/nbd: drop thr->state
We don't need all these states. The code refactored to use two boolean
variables looks simpler.

While moving the comment in nbd_co_establish_connection() rework it to
give better information. Also, we are going to move the connection code
to separate file and mentioning drained section would be confusing.

Improve also the comment in NBDConnectThread, while dropping removed
state names from it.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610100802.5888-12-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: comment tweak]
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:53 -05:00
Vladimir Sementsov-Ogievskiy 08ea55d068 block/nbd: simplify waking of nbd_co_establish_connection()
Instead of managing connect_bh, bh_ctx, and wait_connect fields, we
can use a single link to the waiting coroutine with proper mutex
protection.

So new logic is:

nbd_co_establish_connection() sets wait_co under the mutex, releases
the mutex, then yield()s.  Note that wait_co may be scheduled by the
thread immediately after unlocking the mutex.  Still, the main thread
(or iothread) will not reach the code for entering the coroutine until
the yield(), so we are safe.

connect_thread_func() and nbd_co_establish_connection_cancel() do
the following to handle wait_co:

Under the mutex, if thr->wait_co is not NULL, make it NULL and
schedule it. This way, we avoid scheduling the coroutine twice.

Still scheduling is a bit different:

In connect_thread_func() we can just call aio_co_wake under mutex,
after commit
   [async: the main AioContext is only "current" if under the BQL]
we are sure that aio_co_wake() will not try to acquire the aio context
and do qemu_aio_coroutine_enter() but simply schedule the coroutine by
aio_co_schedule().

nbd_co_establish_connection_cancel() will be called from non-coroutine
context in further patch and will be able to go through
qemu_aio_coroutine_enter() path of aio_co_wake(). So keep current
behavior of waking the coroutine after the critical section.

Also, this commit reduces the dependence of
nbd_co_establish_connection() on the internals of bs (we now use a
generic pointer to the coroutine, instead of direct use of
s->connection_co).  This is a step towards splitting the connection
API out of nbd.c.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610100802.5888-11-vsementsov@virtuozzo.com>
Reviewied-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:53 -05:00
Vladimir Sementsov-Ogievskiy 2def3edb4b block/nbd: BDRVNBDState: drop unused connect_err and connect_status
These fields are write-only. Drop them.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-10-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:53 -05:00
Vladimir Sementsov-Ogievskiy 2a25def4be block/nbd: nbd_client_handshake(): fix leak of s->ioc
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Roman Kagan <rvkagan@yandex-team.ru>
Message-Id: <20210610100802.5888-9-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:53 -05:00
Roman Kagan e8b35bf5dc block/nbd: ensure ->connection_thread is always valid
Simplify lifetime management of BDRVNBDState->connect_thread by
delaying the possible cleanup of it until the BDRVNBDState itself goes
away.

This also reverts
 0267101af6 "block/nbd: fix possible use after free of s->connect_thread"
as now s->connect_thread can't be cleared until the very end.

Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
 [vsementsov: rebase, revert 0267101af6 changes]
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
 [eblake: tweak comment]
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-8-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:53 -05:00
Vladimir Sementsov-Ogievskiy 6cc702beac block/nbd: call socket_address_parse_named_fd() in advance
Detecting monitor by current coroutine works bad when we are not in
coroutine context. And that's exactly so in nbd reconnect code, where
qio_channel_socket_connect_sync() is called from thread.

Monitor is needed only to parse named file descriptor. So, let's just
parse it during nbd_open(), so that all further users of s->saddr don't
need to access monitor.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610100802.5888-7-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:53 -05:00
Vladimir Sementsov-Ogievskiy c542370418 qemu-sockets: introduce socket_address_parse_named_fd()
Add function that transforms named fd inside SocketAddress structure
into number representation. This way it may be then used in a context
where current monitor is not available.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610100802.5888-6-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: comment tweak]
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:53 -05:00
Vladimir Sementsov-Ogievskiy fb392b548e block/nbd: connect_thread_func(): do qio_channel_set_delay(false)
nbd_open() does it (through nbd_establish_connection()).
Actually we lost that call on reconnect path in 1dc4718d84
"block/nbd: use non-blocking connect: fix vm hang on connect()"
when we have introduced reconnect thread.

Fixes: 1dc4718d84
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610100802.5888-5-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:53 -05:00
Vladimir Sementsov-Ogievskiy bbba1c376b block/nbd: fix how state is cleared on nbd_open() failure paths
We have two "return error" paths in nbd_open() after
nbd_process_options(). Actually we should call nbd_clear_bdrvstate()
on these paths. Interesting that nbd_process_options() calls
nbd_clear_bdrvstate() by itself.

Let's fix leaks and refactor things to be more obvious:

- intialize yank at top of nbd_open()
- move yank cleanup to nbd_clear_bdrvstate()
- refactor nbd_open() so that all failure paths except for
  yank-register goes through nbd_clear_bdrvstate()

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-4-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:53 -05:00
Roman Kagan 3687ad4903 block/nbd: fix channel object leak
nbd_free_connect_thread leaks the channel object if it hasn't been
stolen.

Unref it and fix the leak.

Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210610100802.5888-3-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18 10:59:52 -05:00