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2014-10-20block: Make BlockBackend own its BlockDriverStateMarkus Armbruster
On BlockBackend destruction, unref its BlockDriverState. Replaces the callers' unrefs. This turns the pointer from BlockBackend to BlockDriverState into a strong reference, managed with bdrv_ref() / bdrv_unref(). The back-pointer remains weak. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-20block: Connect BlockBackend to BlockDriverStateMarkus Armbruster
Convenience function blk_new_with_bs() creates a BlockBackend with its BlockDriverState. Callers have to unref both. The commit after next will relieve them of the need to unref the BlockDriverState. Complication: due to the silly way drive_del works, we need a way to hide a BlockBackend, just like bdrv_make_anon(). To emphasize its "special" status, give the function a suitably off-putting name: blk_hide_on_behalf_of_do_drive_del(). Unfortunately, hiding turns the BlockBackend's name into the empty string. Can't avoid that without breaking the blk->bs->device_name equals blk->name invariant. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-20block: New BlockBackendMarkus Armbruster
A block device consists of a frontend device model and a backend. A block backend has a tree of block drivers doing the actual work. The tree is managed by the block layer. We currently use a single abstraction BlockDriverState both for tree nodes and the backend as a whole. Drawbacks: * Its API includes both stuff that makes sense only at the block backend level (root of the tree) and stuff that's only for use within the block layer. This makes the API bigger and more complex than necessary. Moreover, it's not obvious which interfaces are meant for device models, and which really aren't. * Since device models keep a reference to their backend, the backend object can't just be destroyed. But for media change, we need to replace the tree. Our solution is to make the BlockDriverState generic, with actual driver state in a separate object, pointed to by member opaque. That lets us replace the tree by deinitializing and reinitializing its root. This special need of the root makes the data structure awkward everywhere in the tree. The general plan is to separate the APIs into "block backend", for use by device models, monitor and whatever other code dealing with block backends, and "block driver", for use by the block layer and whatever other code (if any) dealing with trees and tree nodes. Code dealing with block backends, device models in particular, should become completely oblivious of BlockDriverState. This should let us clean up both APIs, and the tree data structures. This commit is a first step. It creates a minimal "block backend" API: type BlockBackend and functions to create, destroy and find them. BlockBackend objects are created and destroyed exactly when root BlockDriverState objects are created and destroyed. "Root" in the sense of "in bdrv_states". They're not yet used for anything; that'll come shortly. A root BlockDriverState is created with bdrv_new_root(), so where to create a BlockBackend is obvious. Where these roots get destroyed isn't always as obvious. It is obvious in qemu-img.c, qemu-io.c and qemu-nbd.c, and in error paths of blockdev_init(), blk_connect(). That leaves destruction of objects successfully created by blockdev_init() and blk_connect(). blockdev_init() is used only by drive_new() and qmp_blockdev_add(). Objects created by the latter are currently indestructible (see commit 48f364d "blockdev: Refuse to drive_del something added with blockdev-add" and commit 2d246f0 "blockdev: Introduce DriveInfo.enable_auto_del"). Objects created by the former get destroyed by drive_del(). Objects created by blk_connect() get destroyed by blk_disconnect(). BlockBackend is reference-counted. Its reference count never exceeds one so far, but that's going to change. In drive_del(), the BB's reference count is surely one now. The BDS's reference count is greater than one when something else is holding a reference, such as a block job. In this case, the BB is destroyed right away, but the BDS lives on until all extra references get dropped. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-20block: Split bdrv_new_root() off bdrv_new()Markus Armbruster
Creating an anonymous BDS can't fail. Make that obvious. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoît Canet <benoit.canet@nodalink.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-03block: Drop superfluous conditionals around qemu_opts_del()Markus Armbruster
Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 1411999675-14533-1-git-send-email-armbru@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-25qemu-nbd: Destroy the BlockDriverState properlyMarkus Armbruster
Match the bdrv_new() with a bdrv_unref(), just to be tidy. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-22async: aio_context_new(): Handle event_notifier_init failureChrysostomos Nanakos
On a system with a low limit of open files the initialization of the event notifier could fail and QEMU exits without printing any error information to the user. The problem can be easily reproduced by enforcing a low limit of open files and start QEMU with enough I/O threads to hit this limit. The same problem raises, without the creation of I/O threads, while QEMU initializes the main event loop by enforcing an even lower limit of open files. This commit adds an error message on failure: # qemu [...] -object iothread,id=iothread0 -object iothread,id=iothread1 qemu: Failed to initialize event notifier: Too many open files in system Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-08qemu-nbd: fix indentation and coding stylePeter Lieven
Signed-off-by: Peter Lieven <pl@kamp.de> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Benoit Canet <benoit.canet@nodalink.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-08qemu-nbd: add option to set detect-zeroes modePeter Lieven
Signed-off-by: Peter Lieven <pl@kamp.de> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Benoit Canet <benoit.canet@nodalink.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-30nbd: Shutdown socket before closing.Hani Benhabiles
This forces finishing data sending to client before closing the socket like in exports listing or replying with NBD_REP_ERR_UNSUP cases. Signed-off-by: Hani Benhabiles <kroosec@gmail.com> Cc: qemu-stable@nongnu.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-28qemu-nbd: Don't use qerror_report()Markus Armbruster
qerror_report() is a transitional interface to help with converting existing HMP commands to QMP. It should not be used elsewhere. Replace by error_report(). Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-05-24nbd: Miscellaneous typo fixes.Hani Benhabiles
Signed-off-by: Hani Benhabiles <hani@linux.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2014-05-24nbd: Close socket on negotiation failure.Hani Benhabiles
Otherwise, the nbd client may hang waiting for the server response. Signed-off-by: Hani Benhabiles <hani@linux.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2014-04-22block: Add errp to bdrv_new()Kevin Wolf
This patch adds an errp parameter to bdrv_new() and updates all its callers. The next patches will make use of this in order to check for duplicate IDs. Most of the callers know that their ID is fine, so they can simply assert that there is no error. Behaviour doesn't change with this patch yet as bdrv_new() doesn't actually assign errors to errp. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2014-03-17qemu-nbd: Fix coverity issuesPaolo Bonzini
There are two issues in qemu-nbd: a missing return value check after calling accept(), and file descriptor leaks in nbd_client_thread. Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-02-25Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into stagingPeter Maydell
Block patches # gpg: Signature made Fri 21 Feb 2014 21:42:24 GMT using RSA key ID C88F2FD6 # gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" * remotes/kevin/tags/for-upstream: (54 commits) iotests: Mixed quorum child device specifications quorum: Simplify quorum_open() quorum: Add unit test. quorum: Add quorum_open() and quorum_close(). quorum: Implement recursive .bdrv_recurse_is_first_non_filter in quorum. quorum: Add quorum_co_flush(). quorum: Add quorum_invalidate_cache(). quorum: Add quorum_getlength(). quorum: Add quorum mechanism. quorum: Add quorum_aio_readv. blkverify: Extract qemu_iovec_clone() and qemu_iovec_compare() from blkverify. quorum: Add quorum_aio_writev and its dependencies. quorum: Create BDRVQuorumState and BlkDriver and do init. quorum: Create quorum.c, add QuorumChildRequest and QuorumAIOCB. check-qdict: Test termination of qdict_array_split() check-qdict: Adjust test for qdict_array_split() qdict: Extract non-QDicts in qdict_array_split() qemu-config: Sections must consist of keys qemu-iotests: Check qemu-img command line parsing qemu-img: Allow -o help with incomplete argument list ... Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2014-02-21nbd: move socket wrappers to qemu-nbdPaolo Bonzini
qemu-nbd is one of the few valid users of qerror_report_err. Move the error-reporting socket wrappers there. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21block: Add reference parameter to bdrv_open()Max Reitz
Allow bdrv_open() to handle references to existing block devices just as bdrv_file_open() is already capable of. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21block: Change BDS parameter of bdrv_open() to **Max Reitz
Make bdrv_open() take a pointer to a BDS pointer, similarly to bdrv_file_open(). If a pointer to a NULL pointer is given, bdrv_open() will create a new BDS with an empty name; if the BDS pointer is not NULL, that existing BDS will be reused (in the same way as bdrv_open() already did). Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-20util: Split out exec_dir from os_find_datadirFam Zheng
With this change, main() calls qemu_init_exec_dir and uses argv[0] to init exec_dir. The saved value can be retrieved with qemu_get_exec_dir later. It will be reused by module loading. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-12-04qemu-nbd: add doc for option -fWenchao Xia
Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-04qemu-nbd: support internal snapshot exportWenchao Xia
Now it is possible to directly export an internal snapshot, which can be used to probe the snapshot's contents without qemu-img convert. Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-09-12block: Error parameter for open functionsMax Reitz
Add an Error ** parameter to bdrv_open, bdrv_file_open and associated functions to allow more specific error messages. Signed-off-by: Max Reitz <mreitz@redhat.com>
2013-08-22aio / timers: Untangle include filesAlex Bligh
include/qemu/timer.h has no need to include main-loop.h and doing so causes an issue for the next patch. Unfortunately various files assume including timers.h will pull in main-loop.h. Untangle this mess. Signed-off-by: Alex Bligh <alex@alex.org.uk> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-04-15Add -f FMT / --format FMT arg to qemu-nbdDaniel P. Berrange
Currently the qemu-nbd program will auto-detect the format of any disk it is given. This behaviour is known to be insecure. For example, if qemu-nbd initially exposes a 'raw' file to an unprivileged app, and that app runs 'qemu-img create -f qcow2 -o backing_file=/etc/shadow /dev/nbd0' then the next time the app is started, the qemu-nbd will now detect it as a 'qcow2' file and expose /etc/shadow to the unprivileged app. The only way to avoid this is to explicitly tell qemu-nbd what disk format to use on the command line, completely disabling auto-detection. This patch adds a '-f' / '--format' arg for this purpose, mirroring what is already available via qemu-img and qemu commands. qemu-nbd --format raw -p 9000 evil.img will now always use raw, regardless of what format 'evil.img' looks like it contains Signed-off-by: Daniel P. Berrange <berrange@redhat.com> [Use errx, not err. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-03-15block: Add options QDict to bdrv_open() prototypeKevin Wolf
It doesn't do anything yet except storing the options QDict in the BlockDriverState. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-02-22qemu-nbd: add --discard optionPaolo Bonzini
Similar to --cache and --aio, this option mimics the discard suboption of "-drive". Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-12-19block: move include files to include/block/Paolo Bonzini
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-11-12qemu-nbd: initialize main loop before block layerPaolo Bonzini
qemu-nbd was broken because they initialized the block layer while qemu_aio_context was still NULL. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-09-19qemu-nbd: rewrite termination conditions to use a state machinePaolo Bonzini
Use a simple state machine with the following states: - RUNNING => accepting connections - TERMINATE => main loop must call nbd_export_close/put, and not accept connections anymore - TERMINATING => waiting for pending requests to finish - TERMINATED => the NBDExport has been closed Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-09-19nbd: add notification for closing an NBDExportPaolo Bonzini
In order to exit cleanly from qemu-nbd, add a callback that triggers when an NBDExport is closed. In the case of qemu-nbd it will exit the main loop. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-09-19nbd: add reference counting to NBDExportPaolo Bonzini
We will use a similar two-phase destruction for NBDExport, so we need each NBDClient to add a reference to NBDExport. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-09-19nbd: do not close BlockDriverState in nbd_export_closePaolo Bonzini
This is not desirable when embedding the NBD server inside QEMU. Move the bdrv_close to qemu-nbd. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-07-24qemu-nbd: add --cache and --aio optionsPaolo Bonzini
Add two options to tune the I/O implementation of qemu-nbd, matching the possibilities given by the QEMU -drive option. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-07-24qemu-nbd: reorganize help messagePaolo Bonzini
This patch separates qemu-nbd's options in logical groups, thus making the help message easier to read. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-04-19nbd: do not include block_int.hPaolo Bonzini
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-04-19nbd: consistently return negative errno valuesPaolo Bonzini
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>
2012-04-19nbd: consistently check for <0 or >=0Paolo Bonzini
This prepares for the following patch, which changes -1 return values to negative errno. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-02-17open /dev/nbd in nbd_client_threadPaolo Bonzini
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-02-17do not chdir(/) in qemu-nbd before opening all filesMichael Tokarev
When qemu-nbd becomes a daemon it calls daemon(3) with nochdir=0, so daemon(3) changes current directory to /. But at this time, qemu-nbd did not open any user-specified files yet, so by changing current directory, all non-absolute paths becomes wrong. The solution is to pass nochdir=1 to daemon(3) function, and to chdir("/") after all init has been performed, before entering the main loop, -- just like a good daemon should do. This patch is applicable for -stable. Signed-off-by: Michael Tokarev <mjt@tls.msk.ru> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-01-06qemu-nbd: drop loop which can never loopStefan Hajnoczi
For some reason nbd_client_thread() has a do..while loop which can never loop, the condition is bogus because we would take a goto instead. Drop the loop. Reported-by: Dr David Alan Gilbert <davidagilbert@uk.ibm.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2011-12-22qemu-nbd: move client handling to nbd.cPaolo Bonzini
This patch sets up the fd handler in nbd.c instead of qemu-nbd.c. It introduces NBDClient, which wraps the arguments to nbd_trip in a single structure, so that we can add a notifier to it. This way, qemu-nbd can know about disconnections. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2011-12-22qemu-nbd: use common main loopPaolo Bonzini
Using a single main loop for sockets will help yielding from the socket coroutine back to the main loop, and later reentering it. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2011-12-22qemu-nbd: introduce NBDExportPaolo Bonzini
Wrap the common parameters of nbd_trip and nbd_negotiate in a single opaque struct. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2011-12-22qemu-nbd: remove data_size argument to nbd_tripPaolo Bonzini
The size of the buffer is in practice part of the protocol. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2011-12-22qemu-nbd: remove offset argument to nbd_tripPaolo Bonzini
The argument is write-only. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2011-11-11qemu-nbd: open the block device after starting the client threadPaolo Bonzini
This is cleaner, because we do not need to close the block device when there is an error opening /dev/nbdX. It was done this way only to print errors before daemonizing. At the same time, use atexit to ensure that the block device is closed whenever we exit. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-11-11qemu-nbd: fix socket creation racePaolo Bonzini
Now that the client and server are in the same process, there is no need to race on the creation of the socket. We can open the listening socket before starting the client thread. This avoids that "qemu-nbd -v -c" prints this once before connecting successfully to the socket: connect(unix:/var/lock/qemu-nbd-nbd0): No such file or directory Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-11-11qemu-nbd: print error messages from the daemon through a pipePaolo Bonzini
In order to get nice error messages, keep the qemu-nbd process running until before issuing NBD_DO_IT and connected to the daemon with a pipe. This lets the qemu-nbd process relay error messages from the daemon and exit with a nonzero status if appropriate. Suggested-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-11-11qemu-nbd: move client to a threadPaolo Bonzini
This avoids that qemu-nbd uses both forking and threads, which do not behave well together. qemu-nbd is already Unix only, and there is no qemu_thread_join, so for now use pthreads. Since the parent and child no longer have separate file descriptors, we can open the NBD device before daemonizing, instead of checking with access(2) and restricting the open to the client only. Reported-by: Pierre Riteau <pierre.riteau@irisa.fr> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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