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2016-06-28blockjob: assert(cb) when create jobChanglong Xie
Callback for block job should always exist Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Suggested-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Changlong Xie <xiecl.fnst@cn.fujitsu.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com> Message-id: 1466672241-22485-2-git-send-email-xiecl.fnst@cn.fujitsu.com Signed-off-by: Jeff Cody <jcody@redhat.com>
2016-06-20backup: follow AioContext change gracefullyStefan Hajnoczi
Move s->target to the new AioContext when there is an AioContext change. The backup_run() coroutine does not use asynchronous I/O so there is no need to wait for in-flight requests in a BlockJobDriver->pause() callback. Guest writes are intercepted by the backup job. Treat them as guest activity and do it even while the job is paused. This is necessary since the only alternative would be to fail a job that experienced guest writes during pause once the job is resumed. In practice the guest writes don't interfere with AioContext switching since bdrv_drain() is used by bdrv_set_aio_context(). Loops already contain pause points because of block_job_sleep_ns() calls in the yield_and_check() helper function. It is necessary to convert a raw qemu_coroutine_yield() to block_job_yield() so the MIRROR_SYNC_MODE_NONE case can pause. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 1466096189-6477-9-git-send-email-stefanha@redhat.com
2016-05-25backup: Use BlockBackend for I/OKevin Wolf
This changes the backup block job to use the job's BlockBackend for performing its I/O. job->bs isn't used by the backup code any more afterwards. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2016-05-25backup: Remove bs parameter from backup_do_cow()Kevin Wolf
Now that we pass the job to the function, bs is implied by that. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com>
2016-05-25backup: Pack Notifier within BackupBlockJobJohn Snow
Instead of relying on peeking at bs->job, we want to explicitly get a reference to the job that was involved in this notifier callback. Pack the Notifier inside of the BackupBlockJob so we can use container_of to get a reference back to the BackupBlockJob object. This cuts out one more case where we rely unnecessarily on bs->job. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: John Snow <jsnow@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2016-05-25backup: Don't leak BackupBlockJob in error pathKevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com>
2016-05-19blockjob: Don't touch BDS iostatusKevin Wolf
Block jobs don't actually make use of the iostatus for their BDSes, but they manage a separate block job iostatus. Still, they require that it is enabled for the source BDS and they enable it automatically for the target and set the error handling mode - which ends up never being used by the job. This patch removes all of the BDS iostatus handling from the block job, which removes another few bs->blk accesses. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2016-05-19blockjob: Don't set iostatus of targetKevin Wolf
When block job errors were introduced, we assigned the iostatus of the target BDS "just in case". The field has never been accessible for the user because the target isn't listed in query-block. Before we can allow the user to have a second BlockBackend on the target, we need to clean this up. If anything, we would want to set the iostatus for the internal BB of the job (which we can always do later), but certainly not for a separate BB which the job doesn't even use. As a nice side effect, this gets us rid of another bs->blk use. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2016-03-30block: Remove bdrv_(set_)enable_write_cache()Kevin Wolf
The only remaining users were block jobs (mirror and backup) which unconditionally enabled WCE on the BlockBackend of the target image. As these block jobs don't go through BlockBackend for their I/O requests, they aren't affected by this setting anyway but always get a writeback mode, so that call can be removed. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2016-03-22util: move declarations out of qemu-common.hVeronia Bahaa
Move declarations out of qemu-common.h for functions declared in utils/ files: e.g. include/qemu/path.h for utils/path.c. Move inline functions out of qemu-common.h and into new files (e.g. include/qemu/bcd.h) Signed-off-by: Veronia Bahaa <veroniabahaa@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-22include/qemu/osdep.h: Don't include qapi/error.hMarkus Armbruster
Commit 57cb38b included qapi/error.h into qemu/osdep.h to get the Error typedef. Since then, we've moved to include qemu/osdep.h everywhere. Its file comment explains: "To avoid getting into possible circular include dependencies, this file should not include any other QEMU headers, with the exceptions of config-host.h, compiler.h, os-posix.h and os-win32.h, all of which are doing a similar job to this file and are under similar constraints." qapi/error.h doesn't do a similar job, and it doesn't adhere to similar constraints: it includes qapi-types.h. That's in excess of 100KiB of crap most .c files don't actually need. Add the typedef to qemu/typedefs.h, and include that instead of qapi/error.h. Include qapi/error.h in .c files that need it and don't get it now. Include qapi-types.h in qom/object.h for uint16List. Update scripts/clean-includes accordingly. Update it further to match reality: replace config.h by config-target.h, add sysemu/os-posix.h, sysemu/os-win32.h. Update the list of includes in the qemu/osdep.h comment quoted above similarly. This reduces the number of objects depending on qapi/error.h from "all of them" to less than a third. Unfortunately, the number depending on qapi-types.h shrinks only a little. More work is needed for that one. Signed-off-by: Markus Armbruster <armbru@redhat.com> [Fix compilation without the spice devel packages. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-14backup: Use Bitmap to replace "s->bitmap"Fam Zheng
"s->bitmap" tracks done sectors, we only check bit states without using any iterator which HBitmap is good for. Switch to "Bitmap" which is simpler and more memory efficient. Meanwhile, rename it to done_bitmap, to reflect the intention. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 1457412306-18940-2-git-send-email-famz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2016-02-29block/backup: avoid copying less than full target clustersJohn Snow
During incremental backups, if the target has a cluster size that is larger than the backup cluster size and we are backing up to a target that cannot (for whichever reason) pull clusters up from a backing image, we may inadvertantly create unusable incremental backup images. For example: If the bitmap tracks changes at a 64KB granularity and we transmit 64KB of data at a time but the target uses a 128KB cluster size, it is possible that only half of a target cluster will be recognized as dirty by the backup block job. When the cluster is allocated on the target image but only half populated with data, we lose the ability to distinguish between zero padding and uninitialized data. This does not happen if the target image has a backing file that points to the last known good backup. Even if we have a backing file, though, it's likely going to be faster to just buffer the redundant data ourselves from the live image than fetching it from the backing file, so let's just always round up to the target granularity. The same logic applies to backup modes top, none, and full. Copying fractional clusters without the guarantee of COW is dangerous, but even if we can rely on COW, it's likely better to just re-copy the data. Reported-by: Fam Zheng <famz@redhat.com> Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 1456433911-24718-3-git-send-email-jsnow@redhat.com Signed-off-by: Jeff Cody <jcody@redhat.com>
2016-02-29block/backup: make backup cluster size configurableJohn Snow
64K might not always be appropriate, make this a runtime value. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 1456433911-24718-2-git-send-email-jsnow@redhat.com Signed-off-by: Jeff Cody <jcody@redhat.com>
2016-01-20block: Clean up includesPeter Maydell
Clean up includes so that osdep.h is included first and headers which it implies are not included manually. This commit was created with scripts/clean-includes. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-12-03block: Don't wait serialising for non-COR read requestsFam Zheng
The assertion problem was noticed in 06c3916b35a, but it wasn't completely fixed, because even though the req is not marked as serialising, it still gets serialised by wait_serialising_requests against other serialising requests, which could lead to the same assertion failure. Fix it by even more explicitly skipping the serialising for this specific case. Signed-off-by: Fam Zheng <famz@redhat.com> Message-id: 1448962590-2842-2-git-send-email-famz@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-11-12block: Add BlockJobTxn support to backup_runJohn Snow
Allow a BlockJobTxn to be passed into backup_run, which will allow the job to join a transactional group if present. Propagate this new parameter outward into new QMP helper functions in blockdev.c to allow transaction commands to pass forward their BlockJobTxn object in a forthcoming patch. [split up from a patch originally by Stefan and Fam. --js] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: John Snow <jsnow@redhat.com> Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 1446765200-3054-12-git-send-email-jsnow@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-11-12block/backup: Rely on commit/abort for cleanupJohn Snow
Switch over to the new .commit/.abort handlers for cleaning up incremental bitmaps. [split up from a patch originally by Stefan and Fam. --js] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: John Snow <jsnow@redhat.com> Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 1446765200-3054-11-git-send-email-jsnow@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-11-12backup: Extract dirty bitmap handling as a separate functionFam Zheng
This will be reused by the coming new transactional completion code. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 1446765200-3054-5-git-send-email-jsnow@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-10-23block: Move I/O status and error actions into BBMax Reitz
These options are only relevant for the user of a whole BDS tree (like a guest device or a block job) and should thus be moved into the BlockBackend. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-09-25Backup: don't do copy-on-read in before_write_notifierWen Congyang
We will copy data in before_write_notifier to do backup. It is a nested I/O request, so we cannot do copy-on-read. The steps to reproduce it: 1. -drive copy-on-read=on,... // qemu option 2. drive_backup -f disk0 /path_to_backup.img // monitor command Signed-off-by: Wen Congyang <wency@cn.fujitsu.com> Tested-by: Jeff Cody <jcody@redhat.com> Message-id: 1441682913-14320-3-git-send-email-wency@cn.fujitsu.com Signed-off-by: Jeff Cody <jcody@redhat.com>
2015-07-14block: keep bitmap if incremental backup job is cancelledStefan Hajnoczi
Reclaim the dirty bitmap if an incremental backup block job is cancelled. The ret variable may be 0 when the job is cancelled so it's not enough to check ret < 0. Reviewed-by: John Snow <jsnow@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 1434380534-7680-1-git-send-email-stefanha@redhat.com Signed-off-by: Jeff Cody <jcody@redhat.com>
2015-07-02qapi: Rename 'dirty-bitmap' mode to 'incremental'John Snow
If we wish to make differential backups a feature that's easy to access, it might be pertinent to rename the "dirty-bitmap" mode to "incremental" to make it clear what /type/ of backup the dirty-bitmap is helping us perform. This is an API breaking change, but 2.4 has not yet gone live, so we have this flexibility. Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 1433463642-21840-2-git-send-email-jsnow@redhat.com Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-06-22Include qapi/qmp/qerror.h exactly where neededMarkus Armbruster
In particular, don't include it into headers. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
2015-06-22qerror: Clean up QERR_ macros to expand into a single stringMarkus Armbruster
These macros expand into error class enumeration constant, comma, string. Unclean. Has been that way since commit 13f59ae. The error class is always ERROR_CLASS_GENERIC_ERROR since the previous commit. Clean up as follows: * Prepend every use of a QERR_ macro by ERROR_CLASS_GENERIC_ERROR, and delete it from the QERR_ macro. No change after preprocessing. * Rewrite error_set(ERROR_CLASS_GENERIC_ERROR, ...) into error_setg(...). Again, no change after preprocessing. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
2015-04-28block: Ensure consistent bitmap function prototypesJohn Snow
We often don't need the BlockDriverState for functions that operate on bitmaps. Remove it. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 1429314609-29776-15-git-send-email-jsnow@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-04-28qmp: Add support of "dirty-bitmap" sync mode for drive-backupJohn Snow
For "dirty-bitmap" sync mode, the block job will iterate through the given dirty bitmap to decide if a sector needs backup (backup all the dirty clusters and skip clean ones), just as allocation conditions of "top" sync mode. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 1429314609-29776-11-git-send-email-jsnow@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-04-28blockjob: Update function name in commentsFam Zheng
Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 1428069921-2957-5-git-send-email-famz@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-01-13qmp: Add command 'blockdev-backup'Fam Zheng
Similar to drive-backup, but this command uses a device id as target instead of creating/opening an image file. Also add blocker on target bs, since the target is also a named device now. Add check and report error for bs == target which became possible but is an illegal case with introduction of blockdev-backup. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Message-id: 1418899027-8445-3-git-send-email-famz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2014-11-03block: let backup blockjob run in BDS AioContextStefan Hajnoczi
The backup block job must run in the BlockDriverState AioContext so that it works with dataplane. The basics of acquiring the AioContext are easy in blockdev.c. The completion code in block/backup.c must call bdrv_unref() from the main loop. Use block_job_defer_to_main_loop() to achieve that. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 1413889440-32577-8-git-send-email-stefanha@redhat.com
2014-10-20block: Rename BlockDriverCompletionFunc to BlockCompletionFuncMarkus Armbruster
I'll use it with block backends shortly, and the name is going to fit badly there. It's a block layer thing anyway, not just a block driver thing. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-07-09block/backup: Fix hang for unaligned image sizeKevin Wolf
When doing a block backup of an image with an unaligned size (with respect to the BACKUP_CLUSTER_SIZE), qemu would check the allocation status of sectors after the end of the image. bdrv_is_allocated() returns a result that is valid for 0 sectors in this case, so the backup job ran into an endless loop. Stop looping when seeing a result valid for 0 sectors, we're at EOF then. The test case looks somewhat unrelated at first sight because I originally tried to reproduce a different suspected bug that turned out to not exist. Still a good test case and it accidentally found this one. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2014-06-23qapi: adjust existing definesWenchao Xia
In order to let event defines use existing types later, instead of redefine new ones, some old type defines for spice and vnc are changed, and BlockErrorAction is moved from block.h to qapi schema. Note that BlockErrorAction is not merged with BlockdevOnError. At this point, VncInfo is not made a child of VncBasicInfo, because VncBasicInfo has mandatory fields where VncInfo makes them optional. Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-01-24block: Switch BdrvTrackedRequest to byte granularityKevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
2013-11-28block: introduce BDRV_REQ_MAY_UNMAP request flagPeter Lieven
Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28block: add flags to bdrv_*_write_zeroesPeter Lieven
Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-10-11qapi: make use of new BlockJobTypeFam Zheng
Switch the string to enum type BlockJobType in BlockJobDriver. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-11blockjob: rename BlockJobType to BlockJobDriverFam Zheng
We will use BlockJobType as the enum type name of block jobs in QAPI, rename current BlockJobType to BlockJobDriver, which will eventually become a set of operations, similar to block drivers. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-09-06block: make bdrv_co_is_allocated staticPaolo Bonzini
bdrv_is_allocated can detect coroutine context and go through a fast path, similar to other block layer functions. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-09-06block: make bdrv_delete() staticFam Zheng
Manage BlockDriverState lifecycle with refcnt, so bdrv_delete() is no longer public and should be called by bdrv_unref() if refcnt is decreased to 0. This is an identical change because effectively, there's no multiple reference of BDS now: no caller of bdrv_ref() yet, only bdrv_new() sets bs->refcnt to 1, so all bdrv_unref() now actually delete the BDS. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-09-01misc: Fix some typos in names and commentsStefan Weil
Most typos were found using a modified version of codespell: accross -> across issueing -> issuing TICNT_THRESHHOLD -> TICNT_THRESHOLD bandwith -> bandwidth VCARD_7816_PROPIETARY -> VCARD_7816_PROPRIETARY occured -> occurred gaurantee -> guarantee sofware -> software Signed-off-by: Stefan Weil <sw@weilnetz.de> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2013-08-22aio / timers: convert block_job_sleep_ns and co_sleep_ns to new APIAlex Bligh
Convert block_job_sleep_ns and co_sleep_ns to use the new timer API. Signed-off-by: Alex Bligh <alex@alex.org.uk> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-07-26Implement sync modes for drive-backup.Ian Main
This patch adds sync-modes to the drive-backup interface and implements the FULL, NONE and TOP modes of synchronization. FULL performs as before copying the entire contents of the drive while preserving the point-in-time using CoW. NONE only copies new writes to the target drive. TOP copies changes to the topmost drive image and preserves the point-in-time using CoW. For sync mode TOP are creating a new target image using the same backing file as the original disk image. Then any new data that has been laid on top of it since creation is copied in the main backup_run() loop. There is an extra check in the 'TOP' case so that we don't bother to copy all the data of the backing file as it already exists in the target. This is where the bdrv_co_is_allocated() is used to determine if the data exists in the topmost layer or below. Also any new data being written is intercepted via the write_notifier hook which ends up calling backup_do_cow() to copy old data out before it gets overwritten. For mode 'NONE' we create the new target image and only copy in the original data from the disk image starting from the time the call was made. This preserves the point in time data by only copying the parts that are *going to change* to the target image. This way we can reconstruct the final image by checking to see if the given block exists in the new target image first, and if it does not, you can get it from the original image. This is basically an optimization allowing you to do point-in-time snapshots with low overhead vs the 'FULL' version. Since there is no old data to copy out the loop in backup_run() for the NONE case just calls qemu_coroutine_yield() which only wakes up after an event (usually cancel in this case). The rest is handled by the before_write notifier which again calls backup_do_cow() to write out the old data so it can be preserved. Signed-off-by: Ian Main <imain@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-28block: add basic backup support to block driverDietmar Maurer
backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>