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* Do not delete BlockDriverState when deleting the driveRyan Harper2011-04-071-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When removing a drive from the host-side via drive_del we currently have the following path: drive_del qemu_aio_flush() bdrv_close() // zaps bs->drv, which makes any subsequent I/O get // dropped. Works as designed drive_uninit() bdrv_delete() // frees the bs. Since the device is still connected to // bs, any subsequent I/O is a use-after-free. The value of bs->drv becomes unpredictable on free. As long as it remains null, I/O still gets dropped, however it could become non-null at any point after the free resulting SEGVs or other QEMU state corruption. To resolve this issue as simply as possible, we can chose to not actually delete the BlockDriverState pointer. Since bdrv_close() handles setting the drv pointer to NULL, we just need to remove the BlockDriverState from the QLIST that is used to enumerate the block devices. This is currently handled within bdrv_delete, so move this into its own function, bdrv_make_anon(). The result is that we can now invoke drive_del, this closes the file descriptors and sets BlockDriverState->drv to NULL which prevents futher IO to the device, and since we do not free BlockDriverState, we don't have to worry about the copy retained in the block devices. We also don't attempt to remove the qdev property since we are no longer deleting the BlockDriverState on drives with associated drives. This also allows for removing Drives with no devices associated either. Reported-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Ryan Harper <ryanh@us.ibm.com> Acked-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* fdc: move floppy geometry guessing to block.cBlue Swirl2011-02-201-0/+10
| | | | | | | | Other geometry guessing functions already reside in block.c. Remove some unused or debugging only fields. Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
* Add flag to indicate external users to block deviceMarcelo Tosatti2011-02-071-0/+2
| | | | | | | | | | Certain operations such as drive_del or resize cannot be performed while external users (eg. block migration) reference the block device. Add a flag to indicate that. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: tell drivers about an image resizeChristoph Hellwig2011-01-311-1/+2
| | | | | | | | Extend the change_cb callback with a reason argument, and use it to tell drivers about size changes. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: add discard supportChristoph Hellwig2010-12-171-0/+1
| | | | | | | | | Add a new bdrv_discard method to free blocks in a mapping image, and a new drive property to set the granularity for these discard. If no discard granularity support is set discard support is disabled. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qemu-img.c: Re-factor img_create()Jes Sorensen2010-12-171-0/+4
| | | | | | | | | This patch re-factors img_create() moving the code doing the actual work into block.c where it can be shared with QEMU. This is needed to be able to create images from QEMU to be used for live snapshots. Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Allow bdrv_flush to return errorsKevin Wolf2010-11-041-1/+1
| | | | | | | | This changes bdrv_flush to return 0 on success and -errno in case of failure. It's a requirement for implementing proper error handle in users of bdrv_flush. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
* Copy snapshots out of QCOW2 diskedison2010-10-221-0/+2
| | | | | | | | | | | | | | In order to backup snapshots, created from QCOW2 iamge, we want to copy snapshots out of QCOW2 disk to a seperate storage. The following patch adds a new option in "qemu-img": qemu-img convert -f qcow2 -O qcow2 -s snapshot_name src_img bck_img. Right now, it only supports to copy the full snapshot, delta snapshot is on the way. Changes from V1: all the comments from Kevin are addressed: Add read-only checking Fix coding style Change the name from bdrv_snapshot_load to bdrv_snapshot_load_tmp Signed-off-by: Disheng Su <edison@cloud.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Fix BDRV_O_CACHE_MASKKevin Wolf2010-09-081-1/+1
| | | | | | | | BDRV_O_CACHE_MASK should have been extended when cache=unsafe introduced a new flag BDRV_O_NO_FLUSH. There are currently no users that would change their behaviour because of this, but let's clean it up before things break. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* Fix -snapshot deleting images on disk changeBlue Swirl2010-07-261-0/+1
| | | | | | | | | | | Block device change command did not copy BDRV_O_SNAPSHOT flag. Thus the new image did not have this flag and the file got deleted during opening. Fix by copying BDRV_O_SNAPSHOT flag. Signed-off-by: Blue Swirl <blauwirbel@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qemu-img check: Distinguish different kinds of errorsKevin Wolf2010-07-061-1/+9
| | | | | | | | People think that their images are corrupted when in fact there are just some leaked clusters. Differentiating several error cases should make the messages more comprehensible. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Fix virtual media change for if=noneMarkus Armbruster2010-07-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BlockDriverState member removable controls whether virtual media change (monitor commands change, eject) is allowed. It is set when the "type hint" is BDRV_TYPE_CDROM or BDRV_TYPE_FLOPPY. The type hint is only set by drive_init(). It sets BDRV_TYPE_FLOPPY for if=floppy. It sets BDRV_TYPE_CDROM for media=cdrom and if=ide, scsi, xen, or none. if=ide and if=scsi work, because the type hint makes it a CD-ROM. if=xen likewise, I think. For the same reason, if=none works when it's used by ide-drive or scsi-disk. For other guest devices, there are problems: * fdc: you can't change virtual media $ qemu [...] -drive if=none,id=foo,... -global isa-fdc.driveA=foo QEMU 0.12.50 monitor - type 'help' for more information (qemu) eject foo Device 'foo' is not removable unless you add media=cdrom, but that makes it readonly. * virtio: if you add media=cdrom, you can change virtual media. If you eject, the guest gets I/O errors. If you change, the guest sees the drive's contents suddenly change. * scsi-generic: if you add media=cdrom, you can change virtual media. I didn't test what that does to the guest or the physical device, but it can't be pretty. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* savevm: Survive hot-unplug of snapshot deviceMarkus Armbruster2010-07-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | savevm.c keeps a pointer to the snapshot block device. If you manage to get that device deleted, the pointer dangles, and the next snapshot operation will crash & burn. Unplugging a guest device that uses it does the trick: $ MALLOC_PERTURB_=234 qemu-system-x86_64 [...] QEMU 0.12.50 monitor - type 'help' for more information (qemu) info snapshots No available block device supports snapshots (qemu) drive_add auto if=none,file=tmp.qcow2 OK (qemu) device_add usb-storage,id=foo,drive=none1 (qemu) info snapshots Snapshot devices: none1 Snapshot list (from none1): ID TAG VM SIZE DATE VM CLOCK (qemu) device_del foo (qemu) info snapshots Snapshot devices: Segmentation fault (core dumped) Move management of that pointer to block.c, and zap it when the device it points becomes unusable. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Catch attempt to attach multiple devices to a blockdevMarkus Armbruster2010-07-021-0/+3
| | | | | | | | | | | | | | | For instance, -device scsi-disk,drive=foo -device scsi-disk,drive=foo happily creates two SCSI disks connected to the same block device. It's all downhill from there. Device usb-storage deliberately attaches twice to the same blockdev, which fails with the fix in place. Detach before the second attach there. Also catch attempt to delete while a guest device model is attached. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Add bdrv_(p)write_syncKevin Wolf2010-06-221-0/+4
| | | | | | | | | | Add new functions that write and flush the written data to disk immediately. This is what needs to be used for image format metadata to maintain integrity for cache=... modes that don't use O_DSYNC. (Actually, we only need barriers, and therefore the functions are defined as such, but flushes is what is implemented in this patch - we can try to change that later) Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: New bdrv_next()Markus Armbruster2010-06-151-0/+1
| | | | | | | This is a more flexible alternative to bdrv_iterate(). Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Decouple block device "commit all" from DriveInfoMarkus Armbruster2010-06-151-0/+1
| | | | | | | | | | | | | do_commit() and mux_proc_byte() iterate over the list of drives defined with drive_init(). This misses host block devices defined by other means. Such means don't exist now, but will be introduced later in this series. Change them to use new bdrv_commit_all(), which iterates over all host block devices. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Move error actions from DriveInfo to BlockDriverStateMarkus Armbruster2010-06-151-0/+8
| | | | | | | | That's where they belong semantically (block device host part), even though the actions are actually executed by guest device code. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* savevm: Really verify if a drive supports snapshotsMiguel Di Ciurcio Filho2010-06-151-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Both bdrv_can_snapshot() and bdrv_has_snapshot() does not work as advertized. First issue: Their names implies different porpouses, but they do the same thing and have exactly the same code. Maybe copied and pasted and forgotten? bdrv_has_snapshot() is called in various places for actually checking if there is snapshots or not. Second issue: the way bdrv_can_snapshot() verifies if a block driver supports or not snapshots does not catch all cases. E.g.: a raw image. So when do_savevm() is called, first thing it does is to set a global BlockDriverState to save the VM memory state calling get_bs_snapshots(). static BlockDriverState *get_bs_snapshots(void) { BlockDriverState *bs; DriveInfo *dinfo; if (bs_snapshots) return bs_snapshots; QTAILQ_FOREACH(dinfo, &drives, next) { bs = dinfo->bdrv; if (bdrv_can_snapshot(bs)) goto ok; } return NULL; ok: bs_snapshots = bs; return bs; } bdrv_can_snapshot() may return a BlockDriverState that does not support snapshots and do_savevm() goes on. Later on in do_savevm(), we find: QTAILQ_FOREACH(dinfo, &drives, next) { bs1 = dinfo->bdrv; if (bdrv_has_snapshot(bs1)) { /* Write VM state size only to the image that contains the state */ sn->vm_state_size = (bs == bs1 ? vm_state_size : 0); ret = bdrv_snapshot_create(bs1, sn); if (ret < 0) { monitor_printf(mon, "Error while creating snapshot on '%s'\n", bdrv_get_device_name(bs1)); } } } bdrv_has_snapshot(bs1) is not checking if the device does support or has snapshots as explained above. Only in bdrv_snapshot_create() the device is actually checked for snapshot support. So, in cases where the first device supports snapshots, and the second does not, the snapshot on the first will happen anyways. I believe this is not a good behavior. It should be an all or nothing process. This patch addresses these issues by making bdrv_can_snapshot() actually do what it must do and enforces better tests to avoid errors in the middle of do_savevm(). bdrv_has_snapshot() is removed and replaced by bdrv_can_snapshot() where appropriate. bdrv_can_snapshot() was moved from savevm.c to block.c. It makes more sense to me. The loadvm_state() function was updated too to enforce that when loading a VM at least all writable devices must support snapshots too. Signed-off-by: Miguel Di Ciurcio Filho <miguel.filho@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* close all the block drivers before the qemu process exitsMORITA Kazutaka2010-06-041-0/+1
| | | | | | | | | | | This patch calls the close handler of the block driver before the qemu process exits. This is necessary because the sheepdog block driver releases the lock of VM images in the close handler. Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block.h: Make BDRV_SECTOR_SIZE 64 bit safeJes Sorensen2010-05-281-1/+1
| | | | | | | | C defaults to int, so make definition of BDRV_SECTOR_SIZE 64 bit safe as it and BDRV_SECTOR_MASK may be used against 64 bit addresses. Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* add support for protocol driver create_optionsMORITA Kazutaka2010-05-281-0/+1
| | | | | | | | | This patch enables protocol drivers to use their create options which are not supported by the format. For example, protcol drivers can use a backing_file option with raw format. Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* Add cache=unsafe parameter to -driveAlexander Graf2010-05-261-0/+1
| | | | | | | | | | | | | | | Usually the guest can tell the host to flush data to disk. In some cases we don't want to flush though, but try to keep everything in cache. So let's add a new cache value to -drive that allows us to set the cache policy to most aggressive, disabling flushes. We call this mode "unsafe", as guest data is not guaranteed to survive host crashes anymore. This patch also adds a noop function for aio, so we can do nothing in AIO fashion. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
* block: Remove semicolon in BDRV_SECTOR_MASK macroStefan Hajnoczi2010-05-171-1/+1
| | | | | Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: bdrv_has_zero_initKevin Wolf2010-05-031-0/+1
| | | | | | | | | This fixes the problem that qemu-img's use of no_zero_init only considered the no_zero_init flag of the format driver, but not of the underlying protocols. Between the raw/file split and this fix, converting to host devices is broken. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: separate raw images from the file protocolChristoph Hellwig2010-05-031-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We're running into various problems because the "raw" file access, which is used internally by the various image formats is entangled with the "raw" image format, which maps the VM view 1:1 to a file system. This patch renames the raw file backends to the file protocol which is treated like other protocols (e.g. nbd and http) and adds a new "raw" image format which is just a wrapper around calls to the underlying protocol. The patch is surprisingly simple, besides changing the probing logical in block.c to only look for image formats when using bdrv_open and renaming of the old raw protocols to file there's almost nothing in there. For creating images, a new bdrv_create_file is introduced which guesses the protocol to use. This allows using qemu-img create -f raw (or just using the default) for both files and host devices. Converting the other format drivers to use this function to create their images is left for later patches. The only issues still open are in the handling of the host devices. Firstly in current qemu we can specifiy the host* format names on various command line acceping images, but the new code can't do that without adding some translation. Second the layering breaks the no_zero_init flag in the BlockDriver used by qemu-img. I'm not happy how this is done per-driver instead of per-state so I'll prepare a separate patch to clean this up. There's some more cleanup opportunity after this patch, e.g. using separate lists and registration functions for image formats vs protocols and maybe even host drivers, but this can be done at a later stage. Also there's a check for protocol in bdrv_open for the BDRV_O_SNAPSHOT case that I don't quite understand, but which I fear won't work as expected - possibly even before this patch. Note that this patch requires various recent block patches from Kevin and me, which should all be in his block queue. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block.h: bdrv_create2 doesn't exist any moreKevin Wolf2010-04-231-4/+0
| | | | | | | The bdrv_create2 implementation has disappeared long ago. Remove its prototype from the header file, too. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: get rid of the BDRV_O_FILE flagChristoph Hellwig2010-04-231-4/+0
| | | | | | | | | | | | | | | | | | | | BDRV_O_FILE is only used to communicate between bdrv_file_open and bdrv_open. It affects two things: first bdrv_open only searches for protocols using find_protocol instead of all image formats and host drivers. We can easily move that to the caller and pass the found driver to bdrv_open. Second it is used to not force a read-write open of a snapshot file. But we never use bdrv_file_open to open snapshots and this behaviour doesn't make sense to start with. qemu-io abused the BDRV_O_FILE for it's growable option, switch it to using bdrv_file_open to make sure we only open files as growable were we can actually support that. This patch requires Kevin's "[PATCH] Replace calls of old bdrv_open" to be applied first. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* Replace calls of old bdrv_openKevin Wolf2010-04-231-3/+2
| | | | | | | | | What is known today as bdrv_open2 becomes the new bdrv_open. All remaining callers of the old function are converted to the new one. In some places they even know the right format, so they should have used bdrv_open2 from the beginning. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Trigger blkdebug eventsKevin Wolf2010-04-231-0/+44
| | | | | | | This adds blkdebug events to qcow2 to allow injecting I/O errors in specific places. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* blkdebug: Add events and rulesKevin Wolf2010-04-231-0/+9
| | | | | | | | | | | | | Block drivers can trigger a blkdebug event whenever they reach a place where it could be useful to inject an error for testing/debugging purposes. Rules are read from a blkdebug config file and describe which action is taken when an event is triggered. For now this is only injecting an error (with a few options) or changing the state (which is an integer). Rules can be declared to be active only in a specific state; this way later rules can distiguish on which path we came to trigger their event. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: BLOCK_IO_ERROR QMP eventLuiz Capitulino2010-02-101-0/+6
| | | | | | | | | | | | | | | | | | | | | | | This commit introduces the bdrv_mon_event() function, which should be called by block subsystems (eg. IDE) when a I/O error occurs, so that an QMP event is emitted. The following information is currently provided in the event: - device name - operation (ie. "read" or "write") - action taken (eg. "stop") Event example: { "event": "BLOCK_IO_ERROR", "data": { "device": "ide0-hd1", "operation": "write", "action": "stop" }, "timestamp": { "seconds": 1265044230, "microseconds": 450486 } } Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* Count dirty blocks and expose an API to get dirty countLiran Schour2010-02-091-0/+1
| | | | | | | | This will manage dirty counter for each device and will allow to get the dirty counter from above. Signed-off-by: Liran Schour <lirans@il.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* block: kill BDRV_O_CREATChristoph Hellwig2010-01-261-1/+0
| | | | | | | | | The BDRV_O_CREAT option is unused inside qemu and partially duplicates the bdrv_create method. Remove it, and the -C option to qemu-io which isn't used in qemu-iotests anyway. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* No need anymoe for bdrv_set_read_onlyNaphtali Sprei2010-01-261-1/+0
| | | | | Signed-off-by: Naphtali Sprei <nsprei@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* Clean-up a little bit the RW related bits of BDRV_O_FLAGS. BDRV_O_RDONLY ↵Naphtali Sprei2010-01-201-2/+0
| | | | | | | | | | gone (and so is BDRV_O_ACCESS). Default value for bdrv_flags (0/zero) is READ-ONLY. Need to explicitly request READ-WRITE. Instead of using the field 'readonly' of the BlockDriverState struct for passing the request, pass the request in the flags parameter to the function. Signed-off-by: Naphtali Sprei <nsprei@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* block: Add bdrv_change_backing_fileKevin Wolf2010-01-131-0/+2
| | | | | | | | Introduce the functions needed to change the backing file of an image. The function is implemented for qcow2. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* block: Introduce BDRV_O_NO_BACKINGKevin Wolf2010-01-131-0/+1
| | | | | | | | | | | | | If an image references a backing file that doesn't exist, qemu-img info fails to open this image. Exactly in this case the info would be valuable, though: the user might want to find out which file is missing. This patch introduces a BDRV_O_NO_BACKING flag to ignore the backing file when opening the image. qemu-img info is the first user and provides info now even if the backing file is invalid. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* block: Convert bdrv_info_stats() to QObjectLuiz Capitulino2009-12-121-1/+2
| | | | | | | | | | Each device statistic information is stored in a QDict and the returned QObject is a QList of all devices. This commit should not change user output. Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* block: Convert bdrv_info() to QObjectLuiz Capitulino2009-12-121-1/+3
| | | | | | | | | | Each block device information is stored in a QDict and the returned QObject is a QList of all devices. This commit should not change user output. Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* block migration: Increase dirty chunk size to 1MJan Kiszka2009-12-031-1/+1
| | | | | | | | 4K is too small for efficiently saving and restoring multi-GB block devices. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* block migration: Rework constants APIJan Kiszka2009-12-031-1/+6
| | | | | | | | | Instead of duplicating the definition of constants or introducing trivial retrieval functions move the SECTOR constants into the public block API. This also obsoletes sector_per_block in BlkMigState. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* block migration: Fix coding style and whitespacesJan Kiszka2009-12-031-2/+2
| | | | | | | No functional changes. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* Expose a mechanism to trace block writeslirans@il.ibm.com2009-11-171-1/+7
| | | | | | | | | | | | | | | | To support live migration without shared storage we need to be able to trace writes to disk while migrating. This Patch expose dirty block tracking per device to be polled from upper layer. Changes from v4: - Register dirty tracking for each block device. - Minor coding style issues. - Block.c will now manage a dirty bitmap per device once bdrv_set_dirty_tracking() is called. Bitmap is polled by the upper layer (block-migration.c). Signed-off-by: Liran Schour <lirans@il.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* Configurable block format whitelistMarkus Armbruster2009-11-091-0/+2
| | | | | | | | | | | | | | | | | | | | We have code for a quite a few block formats. While I trust that all of these formats are useful at least for some people in some circumstances, some of them are of a kind that friends don't let friends use in production. This patch provides an optional block format whitelist, default off. If a whitelist is configured with --block-drv-whitelist, QEMU proper can use only whitelisted formats. Other programs, like qemu-img, are not affected. Drivers for formats off the whitelist still participate in format probing, to ensure all programs probe exactly the same. Without that, QEMU proper would be prone to treat images with a format off the whitelist as raw when the image's format is probed. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* Added readonly flag to -drive commandNaphtali Sprei2009-11-091-0/+1
| | | | | | | | | | | | | | | | This is a slightly revised patch for adding readonly flag to the -drive command. Even though this patch is "stand-alone", it assumes a previous related patch (in Anthony staging tree), that passes the readonly attribute of the drive to the guest OS, applied first. This enables sharing same image between guests, with readonly access. Implementaion mark the drive as read_only and changes the flags when actually opening the file. The readonly attribute of a qcow also passed to it's base file. For ide that cannot pass the readonly attribute to the guest OS, disallow the readonly flag. Also, return error code from bdrv_truncate for readonly drive. Signed-off-by: Naphtali Sprei <nsprei@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* block: add aio_flush operationChristoph Hellwig2009-09-111-0/+2
| | | | | | | | | | | Instead stalling the VCPU while serving a cache flush try to do it asynchronously. Use our good old helper thread pool to issue an asynchronous fdatasync for raw-posix. Note that while Linux AIO implements a fdatasync operation it is not useful for us because it isn't actually implement in asynchronous fashion. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* block: add enable_write_cache flagChristoph Hellwig2009-09-111-0/+1
| | | | | | | | | | | | | | Add a enable_write_cache flag in the block driver state, and use it to decide if we claim to have a volatile write cache that needs controlled flushing from the guest. The flag is off if cache=writethrough is defined because O_DSYNC guarantees that every write goes to stable storage, and it is on for cache=none and cache=writeback. Both scsi-disk and ide now use the new flage, changing from their defaults of always off (ide) or always on (scsi-disk). Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* Add bdrv_aio_multiwriteKevin Wolf2009-09-111-0/+15
| | | | | | | | | | | | | | | | | One performance problem of qcow2 during the initial image growth are sequential writes that are not cluster aligned. In this case, when a first requests requires to allocate a new cluster but writes only to the first couple of sectors in that cluster, the rest of the cluster is zeroed - just to be overwritten by the following second request that fills up the cluster. Let's try to merge sequential write requests to the same cluster, so we can avoid to write the zero padding to the disk in the first place. As a nice side effect, also other formats take advantage of dealing with less and larger requests. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* raw-posix: add Linux native AIO supportChristoph Hellwig2009-08-271-0/+1
| | | | | | | | | | | | | | | | | | | Now that do have a nicer interface to work against we can add Linux native AIO support. It's an extremly thing layer just setting up an iocb for the io_submit system call in the submission path, and registering an eventfd with the qemu poll handler to do complete the iocbs directly from there. This started out based on Anthony's earlier AIO patch, but after estimated 42,000 rewrites and just as many build system changes there's not much left of it. To enable native kernel aio use the aio=native sub-command on the drive command line. I have also added an option to qemu-io to test the aio support without needing a guest. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
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