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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>
2011-10-27qapi: Convert query-blockstatsLuiz Capitulino1-74/+37
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2011-10-27qapi: Convert query-blockLuiz Capitulino1-82/+30
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2011-10-27block: Rename the BlockIOStatus enum valuesLuiz Capitulino1-8/+10
The biggest change is to rename its prefix from BDRV_IOS to BLOCK_DEVICE_IO_STATUS. Next commit will convert the query-block command to the QAPI and that's how the enumeration is going to be generated. Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2011-10-27block: iostatus: Drop BDRV_IOS_INVALLuiz Capitulino1-2/+3
A future commit will convert bdrv_info() to the QAPI and it won't provide IOS_INVAL. Luckily all we have to do is to add a new 'iostatus_enabled' member to BlockDriverState and use it instead. Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2011-10-21block: change discard to co_discardPaolo Bonzini1-2/+0
Since coroutine operation is now mandatory, convert both bdrv_discard implementations to coroutines. For qcow2, this means taking the lock around the operation. raw-posix remains synchronous. The bdrv_discard callback is then unused and can be eliminated. Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-21block: change flush to co_flushPaolo Bonzini1-2/+0
Since coroutine operation is now mandatory, convert all bdrv_flush implementations to coroutines. For qcow2, this means taking the lock. Other implementations are simpler and just forward bdrv_flush to the underlying protocol, so they can avoid the lock. The bdrv_flush callback is then unused and can be eliminated. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-21block: add bdrv_co_discard and bdrv_aio_discard supportPaolo Bonzini1-11/+91
This similarly adds support for coroutine and asynchronous discard. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-21block: unify flush implementationsPaolo Bonzini1-90/+74
Add coroutine support for flush and apply the same emulation that we already do for read/write. bdrv_aio_flush is simplified to always go through a coroutine. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-21block: rename bdrv_co_rw_bhPaolo Bonzini1-2/+2
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-14block: drop bdrv_has_async_rw()Stefan Hajnoczi1-6/+0
Commit cd74d83345e0e3b708330ab8c4cd9111bb82cda6 ("block: switch bdrv_read()/bdrv_write() to coroutines") removed the bdrv_has_async_rw() callers. This patch removes bdrv_has_async_rw() since it is no longer used. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-14block: drop .bdrv_read()/.bdrv_write() emulationStefan Hajnoczi1-72/+3
There is no need to emulate .bdrv_read()/.bdrv_write() since these interfaces are only called if aio and coroutine interfaces are not present. All valid BlockDrivers must implement either sync, aio, or coroutine interfaces. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-14block: drop emulation functions that use coroutinesStefan Hajnoczi1-54/+7
Block drivers that implement coroutine functions used to get sync and aio wrappers. This is no longer necessary since all request processing now happens in a coroutine. If a block driver implements the coroutine interface then none of the other interfaces will be invoked. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-13block: switch bdrv_aio_writev() to coroutinesStefan Hajnoczi1-64/+2
More sync, aio, and coroutine unification. Make bdrv_aio_writev() go through coroutine request processing. Remove the dirty block callback mechanism which was needed only for aio processing and can be done more naturally in coroutine context. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-13block: mark blocks dirty on coroutine write completionStefan Hajnoczi1-1/+4
The aio write operation marks blocks dirty when the write operation completes. The coroutine write operation marks blocks dirty before issuing the write operation. It seems safest to mark the block dirty when the operation completes so that anything tracking dirty blocks will not act before the change has been made to the image file. Make the coroutine write operation dirty blocks on write completion. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-13block: switch bdrv_aio_readv() to coroutinesStefan Hajnoczi1-13/+35
More sync, aio, and coroutine unification. Make bdrv_aio_readv() go through coroutine request processing. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-13block: switch bdrv_read()/bdrv_write() to coroutinesStefan Hajnoczi1-50/+62
The bdrv_read()/bdrv_write() functions call .bdrv_read()/.bdrv_write(). They should go through bdrv_co_do_readv() and bdrv_co_do_writev() instead in order to unify request processing code across sync, aio, and coroutine interfaces. This is also an important step towards removing BlockDriverState .bdrv_read()/.bdrv_write() in the future. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-13block: split out bdrv_co_do_readv() and bdrv_co_do_writev()Stefan Hajnoczi1-7/+27
The public interface for I/O in coroutine context is bdrv_co_readv() and bdrv_co_writev(). Split out the request processing code into bdrv_co_do_readv() and bdrv_co_writev() so that it can be called internally when we refactor all request processing to use coroutines. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-13block: directly invoke .bdrv_* from emulation functionsStefan Hajnoczi1-6/+8
The emulation functions which supply default BlockDriver .bdrv_*() functions given another implemented .bdrv_*() function should not use public bdrv_*() interfaces. This patch ensures they invoke .bdrv_*() directly to avoid adding an extra layer of coroutine request processing and possibly entering an infinite loop. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-13block: directly invoke .bdrv_aio_*() in bdrv_co_io_em()Stefan Hajnoczi1-4/+4
We will unify block layer request processing across sync, aio, and coroutines and this means a .bdrv_co_*() emulation function should not call back into the public interface. There's no need here, just call .bdrv_aio_*() directly. The gory details: bdrv_co_io_em() cannot call back into the public bdrv_aio_*() interface since that will be handled using coroutines, which causes us to call into bdrv_co_io_em() again in an infinite loop :). Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-11HMP: Print 'io-status' informationLuiz Capitulino1-0/+5
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-11QMP: query-status: Add 'io-status' keyLuiz Capitulino1-0/+12
Contains the I/O status for the given device. The key is only present if the device supports it and the VM is configured to stop on errors. Please, check the documentation being added in this commit for more information. Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-11block: Keep track of devices' I/O statusLuiz Capitulino1-0/+40
This commit adds support to the BlockDriverState type to keep track of devices' I/O status. There are three possible status: BDRV_IOS_OK (no error), BDRV_IOS_ENOSPC (no space error) and BDRV_IOS_FAILED (any other error). The distinction between no space and other errors is important because a management application may want to watch for no space in order to extend the space assigned to the VM and put it to run again. Qemu devices supporting the I/O status feature have to enable it explicitly by calling bdrv_iostatus_enable() _and_ have to be configured to stop the VM on errors (ie. werror=stop|enospc or rerror=stop). In case of multiple errors being triggered in sequence only the first one is stored. The I/O status is always reset to BDRV_IOS_OK when the 'cont' command is issued. Next commits will add support to some devices and extend the query-block/info block commands to return the I/O status information. Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-03trace: add arguments to bdrv_co_io_em() trace eventStefan Hajnoczi1-1/+1
It is useful to know the BlockDriverState as well as the sector_num/nb_sectors of an emulated .bdrv_co_*() request. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2011-10-03trace: trace bdrv_open_common()Stefan Hajnoczi1-0/+2
bdrv_open_common() is a useful point to trace since it reveals the filename and block driver for a given BlockDriverState. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2011-09-12block: New change_media_cb() parameter loadMarkus Armbruster1-6/+6
To let device models distinguish between eject and load. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-09-12block: Reset buffer alignment on detachMarkus Armbruster1-0/+1
BlockDriverState member buffer_alignment is initially 512. The device model may set them, with bdrv_set_buffer_alignment(). If the device model gets detached (hot unplug), the device's alignment is left behind. Only okay because device hot unplug automatically destroys the BlockDriverState. But that's a questionable feature, best not to rely on it. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-09-12block: New bdrv_set_buffer_alignment()Markus Armbruster1-2/+4
Device models should be able to set it without an unclean include of block_int.h. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-09-12block: Show whether the virtual tray is open in info blockMarkus Armbruster1-2/+16
Need to ask the device, so this requires new BlockDevOps member is_tray_open(). Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-09-12block: Drop BlockDriverState member removableMarkus Armbruster1-8/+0
It's a confused mess (see previous commit). No users remain. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-09-12block: Clean up remaining users of "removable"Markus Armbruster1-7/+11
BlockDriverState member removable is a confused mess. It is true when an ide-cd, scsi-cd or floppy qdev is attached, or when the BlockDriverState was created with -drive if={floppy,sd} or -drive if={ide,scsi,xen,none},media=cdrom ("created removable"), except when an ide-hd, scsi-hd, scsi-generic or virtio-blk qdev is attached. Three users remain: 1. eject_device(), via bdrv_is_removable() uses it to determine whether a block device can eject media. 2. bdrv_info() is monitor command "info block". QMP documentation says "true if the device is removable, false otherwise". From the monitor user's point of view, the only sensible interpretation of "is removable" is "can eject media with monitor commands eject and change". A block device can eject media unless a device is attached that doesn't support it. Switch the two users over to new bdrv_dev_has_removable_media() that returns exactly that. 3. bdrv_getlength() uses to suppress its length cache when media can change (see commit 46a4e4e6). Media change is either monitor command change (updates the length cache), monitor command eject (doesn't update the length cache, easily fixable), or physical media change (invalidates length cache, not so easily fixable). I'm refraining from improving anything here, because this series is long enough already. Instead, I simply switch it over to bdrv_dev_has_removable_media() as well. This changes the behavior of the length cache and of monitor commands eject and change in two cases: a. drive not created removable, no device attached The commit makes the drive removable, and defeats the length cache. Example: -drive if=none b. drive created removable, but the attached drive is non-removable, and doesn't call bdrv_set_removable(..., 0) (most devices don't) The commit makes the drive non-removable, and enables the length cache. Example: -drive if=xen,media=cdrom -M xenpv The other non-removable devices that don't call bdrv_set_removable() can't currently use a drive created removable, either because they aren't qdevified, or because they lack a drive property. Won't stay that way. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-09-12block: Rename bdrv_set_locked() to bdrv_lock_medium()Markus Armbruster1-4/+4
While there, make the locked parameter bool. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-09-12block: Drop medium lock tracking, ask device models insteadMarkus Armbruster1-7/+9
Requires new BlockDevOps member is_medium_locked(). Implement for IDE and SCSI CD-ROMs. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-09-12block: Leave enforcing tray lock to device modelsMarkus Armbruster1-6/+1
The device model knows best when to accept the guest's eject command. No need to detour through the block layer. bdrv_eject() can't fail anymore. Make it void. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-09-12block: Drop tray status tracking, no longer usedMarkus Armbruster1-1/+0
Commit 4be9762a is now completely redone. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-09-12block: Revert entanglement of bdrv_is_inserted() with tray statusMarkus Armbruster1-4/+3
Commit 4be9762a changed bdrv_is_inserted() to fail when the tray is open. Unfortunately, there are two different kinds of users, with conflicting needs. 1. Device models using bdrv_eject(), currently ide-cd and scsi-cd. They expect bdrv_is_inserted() to reflect the tray status. Commit 4be9762a makes them happy. 2. Code that wants to know whether a BlockDriverState has media, such as find_image_format(), bdrv_flush_all(). Commit 4be9762a makes them unhappy. In particular, it breaks flush on VM stop for media ejected by the guest. Revert the change to bdrv_is_inserted(). Check the tray status in the device models instead. Note on IDE: Since only ATAPI devices have a tray, and they don't accept ATA commands since the recent commit "ide: Reject ATA commands specific to drive kinds", checking in atapi.c suffices. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-09-06savevm: Include writable devices with removable mediaMarkus Armbruster1-1/+1
savevm and loadvm silently ignore block devices with removable media, such as floppies and SD cards. Rolling back a VM to a previous checkpoint will *not* roll back writes to block devices with removable media. Moreover, bdrv_is_removable() is a confused mess, and wrong in at least one case: it considers "-drive if=xen,media=cdrom -M xenpv" removable. It'll be cleaned up later in this series. Read-only block devices are also ignored, but that's okay. Fix by ignoring only read-only block devices and empty block devices. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-09-06block: Clean up bdrv_flush_all()Markus Armbruster1-2/+1
Change (!bdrv_is_removable(bs) || bdrv_is_inserted(bs)) to just bdrv_is_inserted(). Rationale: The value of bdrv_is_removable(bs) matters only when bdrv_is_inserted(bs) is false. bdrv_is_inserted(bs) is true when bs is open (bs->drv != NULL) and not an empty host drive (CD-ROM or floppy). Therefore, bdrv_is_removable(bs) matters only when: 1. bs is not open old: may call bdrv_flush(bs), which does nothing new: won't call 2. bs is an empty host drive old: may call bdrv_flush(bs), which calls driver method raw_flush(), which calls fdatasync() or equivalent, which can't do anything useful while the drive is empty new: won't call Result is bs->drv && !bdrv_is_read_only(bs) && bdrv_is_inserted(bs). bdrv_is_inserted(bs) implies bs->drv. Drop the redundant test. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-09-06block: Leave tracking media change to device modelsMarkus Armbruster1-14/+6
hw/fdc.c is the only one that cares. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-09-06block: Split change_cb() into change_media_cb(), resize_cb()Markus Armbruster1-8/+15
Multiplexing callbacks complicates matters needlessly. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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