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* aio: add aio_context_acquire() and aio_context_release()Stefan Hajnoczi2014-03-131-0/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | It can be useful to run an AioContext from a thread which normally does not "own" the AioContext. For example, request draining can be implemented by acquiring the AioContext and looping aio_poll() until all requests have been completed. The following pattern should work: /* Event loop thread */ while (running) { aio_context_acquire(ctx); aio_poll(ctx, true); aio_context_release(ctx); } /* Another thread */ aio_context_acquire(ctx); bdrv_read(bs, 0x1000, buf, 1); aio_context_release(ctx); This patch implements aio_context_acquire() and aio_context_release(). Note that existing aio_poll() callers do not need to worry about acquiring and releasing - it is only needed when multiple threads will call aio_poll() on the same AioContext. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: Rewrite the snapshot authorization mechanism for block filters.Benoît Canet2014-03-132-13/+4
| | | | | | | | | | | | | | | | | | | | | This patch keep the recursive way of doing things but simplify it by giving two responsabilities to all block filters implementors. They will need to do two things: -Set the is_filter field of their block driver to true. -Implement the bdrv_recurse_is_first_non_filter method of their block driver like it is done on the Quorum block driver. (block/quorum.c) [Paolo Bonzini <pbonzini@redhat.com> pointed out that this patch changes the semantics of blkverify, which now recurses down both bs->file and s->test_file. -- Stefan] Reported-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* nbd: move socket wrappers to qemu-nbdPaolo Bonzini2014-02-211-4/+0
| | | | | | | | | 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>
* nbd: inline tcp_socket_incoming_spec into sole callerPaolo Bonzini2014-02-211-1/+0
| | | | | | Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* nbd: correctly propagate errorsPaolo Bonzini2014-02-211-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | 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>
* block: Remove bdrv_open_image()'s force_raw optionMax Reitz2014-02-211-1/+1
| | | | | | | | | | This option is now unnecessary since specifying BDRV_O_PROTOCOL as flag will do exactly the same. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Make bdrv_file_open() staticMax Reitz2014-02-211-3/+3
| | | | | | | | | | | | | | Add the bdrv_open() option BDRV_O_PROTOCOL which results in passing the call to bdrv_file_open(). Additionally, make bdrv_file_open() static and therefore bdrv_open() the only way to call it. Consequently, all existing calls to bdrv_file_open() have to be adjusted to use bdrv_open() with the BDRV_O_PROTOCOL flag instead. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Add reference parameter to bdrv_open()Max Reitz2014-02-211-2/+3
| | | | | | | | 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>
* block: Change BDS parameter of bdrv_open() to **Max Reitz2014-02-211-1/+1
| | | | | | | | | | | | 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>
* qemu-iotests: Test pwritev RMW logicKevin Wolf2014-01-241-0/+8
| | | | | Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
* block: Make bdrv_pwrite() a bdrv_prwv_co() wrapperKevin Wolf2014-01-241-1/+0
| | | | | | | | Instead of implementing the alignment adjustment here, use the now existing functionality of bdrv_co_do_pwritev(). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
* block: Allow wait_serialising_requests() at any pointKevin Wolf2014-01-241-0/+2
| | | | | | | | | | | | | | | We can only have a single wait_serialising_requests() call per request because otherwise we can run into deadlocks where requests are waiting for each other. The same is true when wait_serialising_requests() is not at the very beginning of a request, so that other requests can be issued between the start of the tracking and wait_serialising_requests(). Fix this by changing wait_serialising_requests() to ignore requests that are already (directly or indirectly) waiting for the calling request. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
* block: Make overlap range for serialisation dynamicKevin Wolf2014-01-241-0/+4
| | | | | | | | | | | Copy on Read wants to serialise with all requests touching the same cluster, so wait_serialising_requests() rounded to cluster boundaries. Other users like alignment RMW will have different requirements, though (requests touching the same sector), so make it dynamic. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
* block: Generalise and optimise COR serialisationKevin Wolf2014-01-241-2/+3
| | | | | | | | | | | | | | | | Change the API so that specific requests can be marked serialising. Only these requests are checked for overlaps then. This means that during a Copy on Read operation, not all requests overlapping other requests are serialised any more, but only those that actually overlap with the specific COR request. Also remove COR from function and variable names because this functionality can be useful in other contexts. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
* block: Switch BdrvTrackedRequest to byte granularityKevin Wolf2014-01-241-2/+2
| | | | | | Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
* raw: Probe required direct I/O alignmentPaolo Bonzini2014-01-241-0/+3
| | | | | | | | | | | | | | Add a bs->request_alignment field that contains the required offset/length alignment for I/O requests and fill it in the raw block drivers. Use ioctls if possible, else see what alignment it takes for O_DIRECT to succeed. While at it, also expose the memory alignment requirements, which may be (and in practice are) different from the disk alignment requirements. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
* block: rename buffer_alignment to guest_block_sizePaolo Bonzini2014-01-242-3/+3
| | | | | | | | | | | | | | | | | | The alignment field is now set to the value that is promised to the guest, rather than required by the host. The next patches will make QEMU aware of the host-provided values, so make this clear. The alignment is also not about memory buffers, but about the sectors on the disk, change the documentation of the field. At this point, the field is set by the device emulation, but completely ignored by the block layer. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
* block: Don't use guest sector size for qemu_blockalign()Kevin Wolf2014-01-242-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | bs->buffer_alignment is set by the device emulation and contains the logical block size of the guest device. This isn't something that the block layer should know, and even less something to use for determining the right alignment of buffers to be used for the host. The new BlockLimits field opt_mem_alignment tells the qemu block layer the optimal alignment to be used so that no bounce buffer must be used in the driver. This patch may change the buffer alignment from 4k to 512 for all callers that used qemu_blockalign() with the top-level image format BlockDriverState. The value was never propagated to other levels in the tree, so in particular raw-posix never required anything else than 512. While on disks with 4k sectors direct I/O requires a 4k alignment, memory may still be okay when aligned to 512 byte boundaries. This is what must have happened in practice, because otherwise this would already have failed earlier. Therefore I don't expect regressions even with this intermediate state. Later, raw-posix can implement the hook and expose a different memory alignment requirement. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
* block: Update BlockLimits when they might have changedKevin Wolf2014-01-241-0/+1
| | | | | | | | | | | When reopening with different flags, or when backing files disappear from the chain, the limits may change. Make sure they get updated in these cases. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoît Canet <benoit@irqsave.net>
* block: Move initialisation of BlockLimits to bdrv_refresh_limits()Kevin Wolf2014-01-241-0/+2
| | | | | | | | | | This function separates filling the BlockLimits from bdrv_open(), which allows it to call it from other operations which may change the limits (e.g. modifications to the backing file chain or bdrv_reopen) Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
* block: Create authorizations mechanism for external snapshot and resize.Benoît Canet2014-01-242-13/+19
| | | | | Signed-off-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qmp: Allow to change password on named block driver states.Benoît Canet2014-01-241-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Fam Zheng <famz@redhat.com> There was two candidate ways to implement named node manipulation: 1) { 'command': 'block_passwd', 'data': {'*device': 'str', '*node-name': 'str', 'password': 'str'} } 2) { 'command': 'block_passwd', 'data': {'device': 'str', '*device-is-node': 'bool', 'password': 'str'} } Luiz proposed 1 and says 2 was an abuse of the QMP interface and proposed to rewrite the QMP block interface for 2.0. Luiz does not like in 1 the fact that 2 fields are optional but one of them must be specified leading to an abuse of the QMP semantic. Kevin argumented that 2 what a clear abuse of the device field and would not be practical when reading fast some log file because the user would read "device" and think that a device is manipulated when it's in fact a node name. Documentation of 1 make it pretty clear what to do for the user. Kevin argued that all bs are node including devices ones so 2 does not make sense. Kevin also argued that rewriting the QMP block interface would not make disapear the current one. Kevin pushed the argument that making the QAPI generator compatible with the semantic of the operation would need a rewrite that no one has done yet. A vote has been done on the list to elect the version to use and 1 won. For reference the complete thread is: "[Qemu-devel] [PATCH V4 4/7] qmp: Allow to change password on names block driver states." Signed-off-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qmp: Add QMP query-named-block-nodes to list the named BlockDriverState nodes.Benoît Canet2014-01-242-0/+2
| | | | | | Signed-off-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Add bs->node_name to hold the name of a bs node of the bs graph.Benoît Canet2014-01-242-1/+9
| | | | | | | | Add the minimum of code to prepare for the following patches. Signed-off-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Add bdrv_open_image()Max Reitz2014-01-221-0/+3
| | | | | | | | | | | Add a common function for opening images to be used for block drivers specified through BlockdevRefs in an option QDict. The difference from bdrv_file_open() is that this function may invoke bdrv_open() instead, allowing auto-detection of the driver to be used; and second, it automatically extracts the BlockdevRef from the option QDict. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Allow reference for bdrv_file_open()Max Reitz2014-01-221-1/+2
| | | | | | | | | Allow specifying a reference to an existing block device (by name) for bdrv_file_open() instead of a filename and/or options. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Add commit_active_start()Fam Zheng2013-12-201-3/+19
| | | | | | | | | | | | | | | | | | commit_active_start is implemented in block/mirror.c, It will create a job with "commit" type and designated base in block-commit command. This will be used for committing active layer of device. Sync mode is removed from MirrorBlockJob because there's no proper type for commit. The used information is is_none_mode. The common part of mirror_start and commit_active_start is moved to mirror_start_job(). Fix the comment wording for commit_start. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: add opt_transfer_length to BlockLimitsPeter Lieven2013-12-051-0/+3
| | | | | | Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* qemu-nbd: support internal snapshot exportWenchao Xia2013-12-041-0/+8
| | | | | | | | | 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>
* snapshot: distinguish id and name in load_tmpWenchao Xia2013-12-042-2/+9
| | | | | | | | | | | | Since later this function will be used so improve it. The only caller of it now is qemu-img, and it is not impacted by introduce function bdrv_snapshot_load_tmp_by_id_or_name() that call bdrv_snapshot_load_tmp() twice to keep old search logic. bdrv_snapshot_load_tmp_by_id_or_name() return int to let caller know the errno, and errno will be used later. Also fix a typo in comments of bdrv_snapshot_delete(). Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: add bdrv_aio_write_zeroesPaolo Bonzini2013-12-031-0/+3
| | | | | | | | This will be used by the SCSI layer. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: add flags to BlockRequestPaolo Bonzini2013-12-031-0/+1
| | | | | | | | | This lets bdrv_co_do_rw receive flags, so that it can be used for zero writes. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* coroutine: remove unused CoQueue AioContextMarc-André Lureau2013-12-021-1/+0
| | | | | | | | The AioContext ctx field is apparently unused in qemu codebase since 02ffb504485. Signed-off-by: Marc-André Lureau <marcandre.lureau@gmail.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* coroutine: remove qemu_co_queue_wait_insert_headMarc-André Lureau2013-12-021-6/+0
| | | | | | | qemu_co_queue_wait_insert_head() is unused in qemu code base now. Signed-off-by: Marc-André Lureau <marcandre.lureau@gmail.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* blkdebug: add "remove_break" commandFam Zheng2013-11-292-0/+3
| | | | | | | | | This adds "remove_break" command which is the reverse of blkdebug command "break": it removes all breakpoints with given tag and resumes all the requests. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* sheepdog: support user-defined redundancy optionLiu Yuan2013-11-291-0/+1
| | | | | | | | | | | | | | | | | | | Sheepdog support two kinds of redundancy, full replication and erasure coding. # create a fully replicated vdi with x copies -o redundancy=x (1 <= x <= SD_MAX_COPIES) # create a erasure coded vdi with x data strips and y parity strips -o redundancy=x:y (x must be one of {2,4,8,16} and 1 <= y < SD_EC_MAX_STRIP) E.g, to convert a vdi into sheepdog vdi 'test' with 8:3 erasure coding scheme $ qemu-img convert -o redundancy=8:3 linux-0.2.img sheepdog:test Cc: Kevin Wolf <kwolf@redhat.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Liu Yuan <namei.unix@gmail.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* qapi: Change BlockDirtyInfo to listFam Zheng2013-11-291-0/+1
| | | | | | | | We have multiple dirty bitmaps in BDS now, switch QAPI to allow query it (BlockInfo.dirty_bitmaps), and also drop old BlockInfo.dirty. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: per caller dirty bitmapFam Zheng2013-11-292-5/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | Previously a BlockDriverState has only one dirty bitmap, so only one caller (e.g. a block job) can keep track of writing. This changes the dirty bitmap to a list and creates a BdrvDirtyBitmap for each caller, the lifecycle is managed with these new functions: bdrv_create_dirty_bitmap bdrv_release_dirty_bitmap Where BdrvDirtyBitmap is a linked list wrapper structure of HBitmap. In place of bdrv_set_dirty_tracking, a BdrvDirtyBitmap pointer argument is added to these functions, since each caller has its own dirty bitmap: bdrv_get_dirty bdrv_dirty_iter_init bdrv_get_dirty_count bdrv_set_dirty and bdrv_reset_dirty prototypes are unchanged but will internally walk the list of all dirty bitmaps and set them one by one. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: introduce bdrv_make_zeroPeter Lieven2013-11-281-0/+1
| | | | | | | | | | | | this patch adds a call to completely zero out a block device. the operation is sped up by checking the block status and only writing zeroes to the device if they currently do not return zeroes. optionally the zero writing can be sped up by setting the flag BDRV_REQ_MAY_UNMAP to emulate the zero write by unmapping if the driver supports it. Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: add BlockLimits structure to BlockDriverStatePeter Lieven2013-11-281-0/+17
| | | | | | | | this patch adds BlockLimits which introduces discard and write_zeroes limits and alignment information to the BlockDriverState. Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: add wrappers for logical block provisioning informationPeter Lieven2013-11-281-0/+2
| | | | | | | | | | | This adds 2 wrappers to read the unallocated_blocks_are_zero and can_write_zeroes_with_unmap info from the BDI. The wrappers are required to check for the existence of a backing_hd and if the devices are opened with the correct flags. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: add logical block provisioning info to BlockDriverInfoPeter Lieven2013-11-281-0/+16
| | | | | | Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: introduce BDRV_REQ_MAY_UNMAP request flagPeter Lieven2013-11-281-0/+7
| | | | | | Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: add flags to bdrv_*_write_zeroesPeter Lieven2013-11-282-3/+3
| | | | | | Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: make BdrvRequestFlags publicPeter Lieven2013-11-281-0/+5
| | | | | | Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* coroutine: add co_aio_sleep_ns() to allow sleep in block driversMORITA Kazutaka2013-10-301-0/+9
| | | | | | | | | | This helper function behaves similarly to co_sleep_ns(), but the sleeping coroutine will be resumed when using qemu_aio_wait(). Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp> Tested-by: Liu Yuan <namei.unix@gmail.com> Reviewed-by: Liu Yuan <namei.unix@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Avoid unecessary drv->bdrv_getlength() callsKevin Wolf2013-10-291-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The block layer generally keeps the size of an image cached in bs->total_sectors so that it doesn't have to perform expensive operations to get the size whenever it needs it. This doesn't work however when using a backend that can change its size without qemu being aware of it, i.e. passthrough of removable media like CD-ROMs or floppy disks. For this reason, the caching is disabled when a removable device is used. It is obvious that checking whether the _guest_ device has removable media isn't the right thing to do when we want to know whether the size of the host backend can change. To make things worse, non-top-level BlockDriverStates never have any device attached, which makes qemu assume they are removable, so drv->bdrv_getlength() is always called on the protocol layer. In the case of raw-posix, this causes unnecessary lseek() system calls, which turned out to be rather expensive. This patch completely changes the logic and disables bs->total_sectors caching only for certain block driver types, for which a size change is expected: host_cdrom and host_floppy on POSIX, host_device on win32; also the raw format in case it sits on top of one of these protocols, but in the common case the nested bdrv_getlength() call on the protocol driver will use the cache again and avoid an expensive drv->bdrv_getlength() call. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
* block: Add BlockDriver.bdrv_check_ext_snapshot.Benoît Canet2013-10-112-0/+20
| | | | | | | | | | This field is used by blkverify to disable external snapshots creation. It will also be used by block filters like quorum to disable external snapshot creation. Signed-off-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block/get_block_status: avoid redundant callouts on raw devicesPeter Lieven2013-10-111-0/+4
| | | | | | | | | | if a raw device like an iscsi target or host device is used the current implementation makes a second call out to get the block status of bs->file. Signed-off-by: Peter Lieven <pl@kamp.de> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block/qapi: Human-readable ImageInfoSpecific dumpMax Reitz2013-10-111-0/+2
| | | | | | | | | | | | | Add a function for generically dumping the ImageInfoSpecific information in a human-readable format to block/qapi.c. Use this function in bdrv_image_info_dump and qemu-io-cmds.c:info_f to allow qemu-img info resp. qemu-io -c info to print that format specific information. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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