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2012-04-20qemu-img: let 'qemu-img convert' flush dataLiu Yuan1-0/+1
The 'qemu-img convert -h' advertise that the default cache mode is 'writeback', while in fact it is 'unsafe'. This patch 1) fix the help manual and 2) let bdrv_close() call bdrv_flush() 2) is needed because some backend storage doesn't have a self-flush mechanism(for e.g., sheepdog), so we need to call bdrv_flush() to make sure the image is really writen to the storage instead of hanging around writeback cache forever. Signed-off-by: Liu Yuan <tailai.ly@taobao.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-19block: Drain requests in bdrv_closeKevin Wolf1-0/+2
If an AIO request is in flight that refers to a BlockDriverState that has been closed and possibly even freed, more or less anything could happen. I have seen segfaults, -EBADF return values and qcow2 sometimes actually catches the situation in bdrv_close() and abort()s. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
2012-04-05block: add a function to clear incoming live migration flagsBenoît Canet1-0/+9
This function will clear all BDRV_O_INCOMING flags. Signed-off-by: Benoit Canet <benoit.canet@gmail.com> Reviewed-by: Stefan Hajnoczi <stefanha@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-05block: bdrv_append() fixesJeff Cody1-2/+11
A few fixups for bdrv_append(): The new bs (bs_new) passed into bdrv_append() should be anonymous. Rather than call bdrv_make_anon() to enforce this, use an assert to catch when a caller is passing in a bs_new that is not anonymous. Also, the new top layer should have its backing_format reflect the original top's format. And last, after the swap of bs contents, the device_name will have been copied down. This needs to be cleared to reflect the anonymity of the bs that was pushed down. Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-05block: set job->speed in block_set_speedPaolo Bonzini1-1/+7
There is no need to do this in every implementation of set_speed (even though there is only one right now). Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-05block: fix streaming/closing racePaolo Bonzini1-0/+16
Streaming can issue I/O while qcow2_close is running. This causes the L2 caches to become very confused or, alternatively, could cause a segfault when the streaming coroutine is reentered after closing its block device. The fix is to cancel streaming jobs when closing their underlying device. The cancellation must be synchronous, on the other hand qemu_aio_wait will not restart a coroutine that is sleeping in co_sleep. So add a flag saying whether streaming has in-flight I/O. If the busy flag is false, the coroutine is quiescent and, when cancelled, will not issue any new I/O. This protects streaming against closing, but not against deleting. We have a reference count protecting us against concurrent deletion, but I still added an assertion to ensure nothing bad happens. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-05block: disable I/O throttling on sync apiZhi Yong Wu1-0/+20
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com> Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-05block: push recursive flushing up from driversPaolo Bonzini1-8/+14
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-03-12block: handle -EBUSY in bdrv_commit_all()Stefan Hajnoczi1-2/+6
Monitor operations that manipulate image files must not execute while a background job (like image streaming) is in progress. This prevents corruptions from happening when two pieces of code are manipulating the image file without knowledge of each other. The monitor "commit" command raises QERR_DEVICE_IN_USE when bdrv_commit() returns -EBUSY but "commit all" has no error handling. This is easy to fix, although note that we do not deliver a detailed error about which device was busy in the "commit all" case. Suggested-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-02-29qapi: Introduce blockdev-group-snapshot-sync commandJeff Cody1-0/+81
This is a QAPI/QMP only command to take a snapshot of a group of devices. This is similar to the blockdev-snapshot-sync command, except blockdev-group-snapshot-sync accepts a list devices, filenames, and formats. It is attempted to keep the snapshot of the group atomic; if the creation or open of any of the new snapshots fails, then all of the new snapshots are abandoned, and the name of the snapshot image that failed is returned. The failure case should not interrupt any operations. Rather than use bdrv_close() along with a subsequent bdrv_open() to perform the pivot, the original image is never closed and the new image is placed 'in front' of the original image via manipulation of the BlockDriverState fields. Thus, once the new snapshot image has been successfully created, there are no more failure points before pivoting to the new snapshot. This allows the group of disks to remain consistent with each other, even across snapshot failures. Signed-off-by: Jeff Cody <jcody@redhat.com> Acked-by: Luiz Capitulino <lcapitulino@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-02-29block: drop aio_multiwrite in BlockDriverPaolo Bonzini1-20/+3
These were never used. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-02-29block: add a transfer rate for floppy typesHervé Poussineau1-35/+39
Floppies must be read at a specific transfer rate, depending of its own format. Update floppy description table to include required transfer rate. Signed-off-by: Hervé Poussineau <hpoussin@reactos.org> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-02-22qmp: add DEVICE_TRAY_MOVED eventLuiz Capitulino1-0/+24
It's emitted whenever the tray is moved by the guest or by HMP/QMP commands. Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Acked-by: Kevin Wolf <kwolf@redhat.com>
2012-02-22block: bdrv_eject(): Make eject_flag a real boolLuiz Capitulino1-1/+1
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Acked-by: Kevin Wolf <kwolf@redhat.com>
2012-02-22block: Rename bdrv_mon_event() & BlockMonEventActionLuiz Capitulino1-29/+29
They are QMP events, not monitor events. Rename them accordingly. Also, move bdrv_emit_qmp_error_event() up in the file. A new event will be added soon and it's good to have them next each other. Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Acked-by: Kevin Wolf <kwolf@redhat.com>
2012-02-09block: perform zero-detection during copy-on-readStefan Hajnoczi1-3/+11
Copy-on-Read populates the image file with data read from a backing image. In order to avoid bloating the image file when all zeroes are read we should scan the buffer and perform an optimized zero write operation. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-02-09block: add .bdrv_co_write_zeroes() interfaceStefan Hajnoczi1-6/+47
The ability to zero regions of an image file is a useful primitive for higher-level features such as image streaming or zero write detection. Image formats may support an optimized metadata representation instead of writing zeroes into the image file. This allows zero writes to be potentially faster than regular write operations and also preserve sparseness of the image file. The .bdrv_co_write_zeroes() interface should be implemented by block drivers that wish to provide efficient zeroing. Note that this operation is different from the discard operation, which may leave the contents of the region indeterminate. That means discarded blocks are not guaranteed to contain zeroes and may contain junk data instead. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-01-26block: add bdrv_find_backing_imageMarcelo Tosatti1-0/+18
Add bdrv_find_backing_image: given a BlockDriverState pointer, and an id, traverse the backing image chain to locate the id. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-01-26block: add BlockJob interface for long-running operationsStefan Hajnoczi1-0/+48
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-01-26block: make copy-on-read a per-request flagStefan Hajnoczi1-11/+38
Previously copy-on-read could only be enabled for all requests to a block device. This means requests coming from the guest as well as QEMU's internal requests would perform copy-on-read when enabled. For image streaming we want to support finer-grained behavior than just populating the image file from its backing image. Image streaming supports partial streaming where a common backing image is preserved. In this case guest requests should not perform copy-on-read because they would indiscriminately copy data which should be left in a backing image from the backing chain. Introduce a per-request flag for copy-on-read so that a block device can process both regular and copy-on-read requests. Overlapping reads and writes still need to be serialized for correctness when copy-on-read is happening, so add an in-flight reference count to track this. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-01-26block: check bdrv_in_use() before blockdev operationsStefan Hajnoczi1-0/+4
Long-running block operations like block migration and image streaming must have continual access to their block device. It is not safe to perform operations like hotplug, eject, change, resize, commit, or external snapshot while a long-running operation is in progress. This patch adds the missing bdrv_in_use() checks so that block migration and image streaming never have the rug pulled out from underneath them. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-15block: avoid useless checks on acb->bhPaolo Bonzini1-3/+1
Coverity is confused by this "if" and reports leaks on acb->bh. The bottom half is always deleted before releasing the AIOCB, in either bdrv_aio_cancel_em or bdrv_aio_bh_cb. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-15block: simplify failure handling for bdrv_aio_multiwritePaolo Bonzini1-26/+2
Now that early failure of bdrv_aio_writev is not possible anymore, mcb->num_requests can be set before the loop starts. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-15block: bdrv_aio_* do not return NULLPaolo Bonzini1-23/+1
Initially done with the following semantic patch: @ rule1 @ expression E; statement S; @@ E = ( bdrv_aio_readv | bdrv_aio_writev | bdrv_aio_flush | bdrv_aio_discard | bdrv_aio_ioctl ) (...); ( - if (E == NULL) { ... } | - if (E) { <... S ...> } ) which however missed the occurrence in block/blkverify.c (as it should have done), and left behind some unused variables. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05block: convert qemu_aio_flush() calls to bdrv_drain_all()Stefan Hajnoczi1-0/+19
Many places in QEMU call qemu_aio_flush() to complete all pending asynchronous I/O. Most of these places actually want to drain all block requests but there is no block layer API to do so. This patch introduces the bdrv_drain_all() API to wait for requests across all BlockDriverStates to complete. As a bonus we perform checks after qemu_aio_wait() to ensure that requests really have finished. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05block: wait_for_overlapping_requests() deadlock detectionStefan Hajnoczi1-0/+8
Debugging a reentrant request deadlock was fun but in the future we need a quick and obvious way of detecting such bugs. Add an assert that checks we are not about to deadlock when waiting for another request. Suggested-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05block: implement bdrv_co_is_allocated() boundary casesStefan Hajnoczi1-8/+18
Cases beyond the end of the disk image are only implemented for block drivers that do not provide .bdrv_co_is_allocated(). It's worth making these cases generic so that block drivers that do implement .bdrv_co_is_allocated() also get them for free. Suggested-by: Mark Wu <wudxw@linux.vnet.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05block: core copy-on-read logicStefan Hajnoczi1-0/+72
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05block: request overlap detectionStefan Hajnoczi1-2/+43
Detect overlapping requests and remember to align to cluster boundaries if the image format uses them. This assumes that allocating I/O is performed in cluster granularity - which is true for qcow2, qed, etc. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05block: wait for overlapping requestsStefan Hajnoczi1-0/+35
When copy-on-read is enabled it is necessary to wait for overlapping requests before issuing new requests. This prevents races between the copy-on-read and a write request. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05block: add interface to toggle copy-on-readStefan Hajnoczi1-0/+22
The bdrv_enable_copy_on_read()/bdrv_disable_copy_on_read() functions can be used to programmatically enable or disable copy-on-read for a block device. Later patches add the actual copy-on-read logic. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05block: add request trackingStefan Hajnoczi1-1/+47
The block layer does not know about pending requests. This information is necessary for copy-on-read since overlapping requests must be serialized to prevent races that corrupt the image. The BlockDriverState gets a new tracked_request list field which contains all pending requests. Each request is a BdrvTrackedRequest record with sector_num, nb_sectors, and is_write fields. Note that request tracking is always enabled but hopefully this extra work is so small that it doesn't justify adding an enable/disable flag. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05block: add bdrv_co_is_allocated() interfaceStefan Hajnoczi1-13/+24
This patch introduces the public bdrv_co_is_allocated() interface which can be used to query image allocation status while the VM is running. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05block: drop .bdrv_is_allocated() interfaceStefan Hajnoczi1-20/+18
Now that all block drivers have been converted to .bdrv_co_is_allocated() we can drop .bdrv_is_allocated(). Note that the public bdrv_is_allocated() interface is still available but is in fact a synchronous wrapper around .bdrv_co_is_allocated(). Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05block: add .bdrv_co_is_allocated()Stefan Hajnoczi1-0/+37
This patch adds the .bdrv_co_is_allocated() interface which is identical to .bdrv_is_allocated() but runs in coroutine context. Running in coroutine context implies that other coroutines might be performing I/O at the same time. Therefore it must be safe to run while the following BlockDriver functions are in-flight: .bdrv_co_readv() .bdrv_co_writev() .bdrv_co_flush() .bdrv_co_is_allocated() The new .bdrv_co_is_allocated() interface is useful because it can be used when a VM is running, whereas .bdrv_is_allocated() is a synchronous interface that does not cope with parallel requests. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05block: use public bdrv_is_allocated() interfaceStefan Hajnoczi1-1/+1
There is no need for bdrv_commit() to use the BlockDriver .bdrv_is_allocated() interface directly. Converting to the public interface gives us the freedom to drop .bdrv_is_allocated() entirely in favor of a new .bdrv_co_is_allocated() in the future. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05hmp/qmp: add block_set_io_throttleZhi Yong Wu1-0/+15
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05block: add I/O throttling algorithmZhi Yong Wu1-0/+234
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05block: add the blockio limits command line supportZhi Yong Wu1-0/+39
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-11-21block: allow migration to work with image files (v3)Anthony Liguori1-0/+16
Image files have two types of data: immutable data that describes things like image size, backing files, etc. and mutable data that includes offset and reference count tables. Today, image formats aggressively cache mutable data to improve performance. In some cases, this happens before a guest even starts. When dealing with live migration, since a file is open on two machines, the caching of meta data can lead to data corruption. This patch addresses this by introducing a mechanism to invalidate any cached mutable data a block driver may have which is then used by the live migration code. NB, this still requires coherent shared storage. Addressing migration without coherent shared storage (i.e. NFS) requires additional work. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2011-11-11block: Make cache=unsafe flush to the OSKevin Wolf1-3/+7
cache=unsafe completely ignored bdrv_flush, because flushing the host disk costs a lot of performance. However, this means that qcow2 images (and potentially any other format) can lose data even after the guest has issued a flush if the qemu process crashes/is killed. In case of a host crash, data loss is certainly expected with cache=unsafe, but if just the qemu process dies this is a bit too unsafe. Now that we have two separate flush functions, we can choose to flush everythign to the OS, but don't enforce that it's physically written to the disk. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-11-11block: Introduce bdrv_co_flush_to_osKevin Wolf1-1/+12
qcow2 has a writeback metadata cache, so flushing a qcow2 image actually consists of writing back that cache to the protocol and only then flushes the protocol in order to get everything stable on disk. This introduces a separate bdrv_co_flush_to_os to reflect the split. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-11-11block: Rename bdrv_co_flush to bdrv_co_flush_to_diskKevin Wolf1-2/+2
There are two different types of flush that you can do: Flushing one level up to the OS (i.e. writing data to the host page cache) or flushing it all the way down to the disk. The existing functions flush to the disk, reflect this in the function name. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-11-11block: add eject request callbackPaolo Bonzini1-0/+7
Recent versions of udev always keep the tray locked so that the kernel can observe "eject request" events (aka tray button presses) even on discs that aren't mounted. Add support for these events in the ATAPI and SCSI cd drive device models. To let management cope with the behavior of udev, an event should also be added for "tray opened/closed". This way, after issuing an "eject" command, management can poll until the guests actually reacts to the command. They can then issue the "change" command after the tray has been opened, or try with "eject -f" after a (configurable?) timeout. However, with this patch and the corresponding support in the device models, at least it is possible to do a manual two-step eject+change sequence. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-31Merge remote-tracking branch 'kwolf/for-anthony' into stagingAnthony Liguori1-10/+8
Conflicts: block/vmdk.c
2011-10-28block: reinitialize across bdrv_close()/bdrv_open()Stefan Hajnoczi1-2/+4
Several BlockDriverState fields are not being reinitialized across bdrv_close()/bdrv_open(). Make sure they are reset to their default values. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-28block: set bs->read_only before .bdrv_open()Stefan Hajnoczi1-2/+2
Several block drivers set bs->read_only in .bdrv_open() but block.c:bdrv_open_common() clobbers its value. Additionally, QED uses bdrv_is_read_only() in .bdrv_open() to decide whether to perform consistency checks. The correct ordering is to initialize bs->read_only from the open flags before calling .bdrv_open(). This way block drivers can override it if necessary and can use bdrv_is_read_only() in .bdrv_open(). Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-28block: Fix bdrv_open use after freeKevin Wolf1-1/+1
tmp_filename was used outside the block it was defined in, i.e. after it went out of scope. Move its declaration to the top level. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-28block: Remove dead codeKevin Wolf1-5/+1
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-27Drop qemu-objects.h from modules that don't require itLuiz Capitulino1-1/+1
Previous commits dropped most qobjects usage from qemu modules (now they are a low level interface used by the QAPI). However, some modules still include the qemu-objects.h header file. This commit drops qemu-objects.h from some of those modules and includes qjson.h instead, which is what they actually need. Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
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