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2014-06-27quorum: Add the rewrite-corrupted parameter to quorumBenoît Canet
On read operations when this parameter is set and some replicas are corrupted while quorum can be reached quorum will proceed to rewrite the correct version of the data to fix the corrupted replicas. This will shine with SSD where the FTL will remap the same block at another place on rewrite. Signed-off-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-06-23qapi event: convert QUORUM eventsWenchao Xia
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>
2014-06-04quorum: implement .bdrv_detach/attach_aio_context()Stefan Hajnoczi
Implement .bdrv_detach/attach_aio_context() interfaces to propagate detach/attach to BDRVQuorumState->bs[] children. The block layer takes care of ->file and ->backing_hd but doesn't know about our ->bs[] BlockDriverStates, which is also part of the graph. Reviewed-by: Benoît Canet <benoit.canet@irqsave.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-04-25Use error_is_set() only when necessary (again)Markus Armbruster
error_is_set(&var) is the same as var != NULL, but it takes whole-program analysis to figure that out. Unnecessarily hard for optimizers, static checkers, and human readers. Commit 84d18f0 dumbed it down to obvious, but a few more have crept in since, and documentation was overlooked. Dumb these down, too. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-03-19block: Add error handling to bdrv_invalidate_cache()Kevin Wolf
If it returns an error, the migrated VM will not be started, but qemu exits with an error message. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-03-13block: Rewrite the snapshot authorization mechanism for block filters.Benoît Canet
This patch keep the recursive way of doing things but simplify it by giving two responsabilities to all block filters implementors. They will need to do two things: -Set the is_filter field of their block driver to true. -Implement the bdrv_recurse_is_first_non_filter method of their block driver like it is done on the Quorum block driver. (block/quorum.c) [Paolo Bonzini <pbonzini@redhat.com> pointed out that this patch changes the semantics of blkverify, which now recurses down both bs->file and s->test_file. -- Stefan] Reported-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-02-28qmp: Make Quorum error events more palatable.Benoît Canet
Insert quorum QMP events documentation alphabetically. Also change the "ret" errno value by an optional "error" being an strerror(-ret) in the QUORUM_REPORT_BAD qmp event. Signed-off-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-02-21quorum: Simplify quorum_open()Max Reitz
Although it may not look like it, this patch simplifies quorum_open(). qdict_array_split() is now able to return QLists with different objects than only QDicts, therefore it will now do all the work and quorum_open() does not have to handle reference strings by itself. This allows mixing full option dicts and reference strings for specifying the child block devices of quorum; furthermore, it improves handling of malformed specifications. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21quorum: Add quorum_open() and quorum_close().Benoît Canet
Example of command line: -drive if=virtio,driver=quorum,\ children.0.file.filename=1.raw,\ children.0.node-name=1.raw,\ children.0.driver=raw,\ children.1.file.filename=2.raw,\ children.1.node-name=2.raw,\ children.1.driver=raw,\ children.2.file.filename=3.raw,\ children.2.node-name=3.raw,\ children.2.driver=raw,\ vote-threshold=2 blkverify=on with vote-threshold=2 and two files can be passed to emulate blkverify. Signed-off-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21quorum: Implement recursive .bdrv_recurse_is_first_non_filter in quorum.Benoît Canet
This is used to activate quorum snapshot. Signed-off-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21quorum: Add quorum_co_flush().Benoît Canet
Makes a vote to select error if any. Signed-off-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21quorum: Add quorum_invalidate_cache().Benoît Canet
We really want that live migration works with quorum so implement quorum_invalidate_cache(). Signed-off-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21quorum: Add quorum_getlength().Benoît Canet
Check that every bs file returns the same length. Otherwise, return -EIO to disable the quorum and avoid length discrepancy. Signed-off-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21quorum: Add quorum mechanism.Benoît Canet
This patchset enables the core of the quorum mechanism. The num_children reads are compared to get the majority version and if this version exists more than threshold times the guest won't see the error at all. If a block is corrupted or if an error occurs during an IO or if the quorum cannot be established QMP events are used to report to the management. Use gnutls's SHA-256 to compare versions. --enable-quorum must be used to enable the feature. Signed-off-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21quorum: Add quorum_aio_readv.Benoît Canet
Add code to do num_children reads in parallel and cleanup the structures afterwards. Signed-off-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21quorum: Add quorum_aio_writev and its dependencies.Benoît Canet
Writes are mirrored num_children times on num_children devices. Signed-off-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21quorum: Create BDRVQuorumState and BlkDriver and do init.Benoît Canet
Create the structure holding the quorum settings and write the minimal block driver instanciation boilerplate. Signed-off-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21quorum: Create quorum.c, add QuorumChildRequest and QuorumAIOCB.Benoît Canet
Quorum is a block filter mirroring writes to num_children children. For reads quorum reads each children and does a vote. If more than vote_threshold versions are identical the quorum is reached and this winning version is returned to the guest. So quorum prevents bit corruption. For high availability purpose minority errors are reported via QMP but the guest does not see them. This patch creates the driver C source file and introduces the structures that will be used in asynchronous reads and writes. Signed-off-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>