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2018-05-15migration: new cmd MIG_CMD_RECV_BITMAPPeter Xu3-0/+64
Add a new vm command MIG_CMD_RECV_BITMAP to request received bitmap for one ramblock. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20180502104740.12123-12-peterx@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2018-05-15migration: wakeup dst ram-load-thread for recoverPeter Xu1-2/+28
On the destination side, we cannot wake up all the threads when we got reconnected. The first thing to do is to wake up the main load thread, so that we can continue to receive valid messages from source again and reply when needed. At this point, we switch the destination VM state from postcopy-paused back to postcopy-recover. Now we are finally ready to do the resume logic. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20180502104740.12123-11-peterx@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2018-05-15migration: new state "postcopy-recover"Peter Xu2-20/+60
Introducing new migration state "postcopy-recover". If a migration procedure is paused and the connection is rebuilt afterward successfully, we'll switch the source VM state from "postcopy-paused" to the new state "postcopy-recover", then we'll do the resume logic in the migration thread (along with the return path thread). This patch only do the state switch on source side. Another following up patch will handle the state switching on destination side using the same status bit. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20180502104740.12123-10-peterx@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> --- s/2.11/2.13/
2018-05-15migration: rebuild channel on sourcePeter Xu1-21/+70
This patch detects the "resume" flag of migration command, rebuild the channels only if the flag is set. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20180502104740.12123-9-peterx@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2018-05-15qmp: hmp: add migrate "resume" optionPeter Xu4-6/+12
It will be used when we want to resume one paused migration. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20180502104740.12123-8-peterx@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> --- s/2.12/2.13/
2018-05-15migration: allow fault thread to pausePeter Xu5-4/+57
Allows the fault thread to stop handling page faults temporarily. When network failure happened (and if we expect a recovery afterwards), we should not allow the fault thread to continue sending things to source, instead, it should halt for a while until the connection is rebuilt. When the dest main thread noticed the failure, it kicks the fault thread to switch to pause state. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20180502104740.12123-7-peterx@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2018-05-15migration: allow src return path to pausePeter Xu3-2/+36
Let the thread pause for network issues. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20180502104740.12123-6-peterx@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2018-05-15migration: allow dst vm pause on postcopyPeter Xu4-2/+67
When there is IO error on the incoming channel (e.g., network down), instead of bailing out immediately, we allow the dst vm to switch to the new POSTCOPY_PAUSE state. Currently it is still simple - it waits the new semaphore, until someone poke it for another attempt. One note is that here on ram loading thread we cannot detect the POSTCOPY_ACTIVE state, but we need to detect the more specific POSTCOPY_INCOMING_RUNNING state, to make sure we have already loaded all the device states. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20180502104740.12123-5-peterx@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2018-05-15migration: implement "postcopy-pause" src logicPeter Xu3-6/+97
Now when network down for postcopy, the source side will not fail the migration. Instead we convert the status into this new paused state, and we will try to wait for a rescue in the future. If a recovery is detected, migration_thread() will reset its local variables to prepare for that. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20180502104740.12123-4-peterx@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2018-05-15migration: new postcopy-pause statePeter Xu2-1/+6
Introducing a new state "postcopy-paused", which can be used when the postcopy migration is paused. It is targeted for postcopy network failure recovery. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20180502104740.12123-3-peterx@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2018-05-15migration: let incoming side use thread contextPeter Xu3-13/+12
The old incoming migration is running in main thread and default gcontext. With the new qio_channel_add_watch_full() we can now let it run in the thread's own gcontext (if there is one). Currently this patch does nothing alone. But when any of the incoming migration is run in another iothread (e.g., the upcoming migrate-recover command), this patch will bind the incoming logic to the iothread instead of the main thread (which may already get page faulted and hanged). RDMA is not considered for now since it's not even using the QIO watch framework at all. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20180502104740.12123-2-peterx@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2018-05-15migration: Define MultifdRecvParams soonerJuan Quintela1-15/+31
Once there, we don't need the struct names anywhere, just the typedefs. And now also document all fields. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2018-05-15migration: Transmit initial package through the multifd channelsJuan Quintela1-5/+99
Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> -- Be network agnostic. Add error checking for all values.
2018-05-15migration: Delay start of migration main routinesJuan Quintela4-2/+10
We need to make sure that we have started all the multifd threads. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2018-05-15migration: Create multifd channelsJuan Quintela1-10/+42
In both sides. We still don't transmit anything through them. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2018-05-15migration: Export functions to create send channelsJuan Quintela2-1/+34
Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2018-05-15migration: Be sure all recv channels are createdJuan Quintela3-1/+17
We need them before we start migration. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2018-05-15migration: terminate_* can be called for other threadsJuan Quintela1-14/+30
Once there, make count field to always be accessed with atomic operations. To make blocking operations, we need to know that the thread is running, so create a bool to indicate that. Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> -- Once here, s/terminate_multifd_*-threads/multifd_*_terminate_threads/ This is consistente with every other function
2018-05-15migration: Introduce multifd_recv_new_channel()Juan Quintela3-1/+10
Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2018-05-15migration: Set error state in case of errorJuan Quintela1-2/+24
Signed-off-by: Juan Quintela <quintela@redhat.com>
2018-05-15tests: Migration ppc now inlines its programJuan Quintela1-36/+5
No need to write it to a file. Just need a proper firmware O:-) Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Laurent Vivier <lvivier@redhat.com> Reviewed-by: Thomas Huth <thuth@redhat.com>
2018-05-15tests: Add migration precopy testJuan Quintela1-2/+42
Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com>
2018-05-15migration: fix saving normal page even if it's been compressedXiao Guangrong1-1/+1
Fix the bug introduced by da3f56cb2e767016 (migration: remove ram_save_compressed_page()), It should be 'return' rather than 'res' Sorry for this stupid mistake :( Signed-off-by: Xiao Guangrong <xiaoguangrong@tencent.com> Message-Id: <20180428081045.8878-1-xiaoguangrong@tencent.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
2018-05-15Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into stagingPeter Maydell60-429/+1174
Block layer patches: - Switch AIO/callback based block drivers to a byte-based interface - Block jobs: Expose error string via query-block-jobs - Block job cleanups and fixes - hmp: Allow using a qdev id in block_set_io_throttle # gpg: Signature made Tue 15 May 2018 16:33:10 BST # gpg: using RSA key 7F09B272C88F2FD6 # gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" # Primary key fingerprint: DC3D EB15 9A9A F95D 3D74 56FE 7F09 B272 C88F 2FD6 * remotes/kevin/tags/for-upstream: (37 commits) iotests: Add test for -U/force-share conflicts qemu-img: Use only string options in img_open_opts qemu-io: Use purely string blockdev options block: Document BDRV_REQ_WRITE_UNCHANGED support qemu-img: Check post-truncation size iotests: Add test for COR across nodes iotests: Copy 197 for COR filter driver iotests: Clean up wrap image in 197 block: Support BDRV_REQ_WRITE_UNCHANGED in filters block/quorum: Support BDRV_REQ_WRITE_UNCHANGED block: Set BDRV_REQ_WRITE_UNCHANGED for COR writes block: Add BDRV_REQ_WRITE_UNCHANGED flag block: BLK_PERM_WRITE includes ..._UNCHANGED block: Add COR filter driver iotests: Skip 181 and 201 without userfaultfd iotests: Add failure matching to common.qemu docs: Document the new default sizes of the qcow2 caches qcow2: Give the refcount cache the minimum possible size by default specs/qcow2: Clarify that compressed clusters have the COPIED bit reset Fix error message about compressed clusters with OFLAG_COPIED ... Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-05-15Merge remote-tracking branch 'mreitz/tags/pull-block-2018-05-15' into ↵Kevin Wolf36-159/+862
queue-block - Copy-on-read block driver - The qcow2 default refcount cache size has been decreased - Various bug fixes # gpg: Signature made Tue May 15 16:18:25 2018 CEST # gpg: using RSA key F407DB0061D5CF40 # gpg: Good signature from "Max Reitz <mreitz@redhat.com>" # Primary key fingerprint: 91BE B60A 30DB 3E88 57D1 1829 F407 DB00 61D5 CF40 * mreitz/tags/pull-block-2018-05-15: (21 commits) iotests: Add test for -U/force-share conflicts qemu-img: Use only string options in img_open_opts qemu-io: Use purely string blockdev options block: Document BDRV_REQ_WRITE_UNCHANGED support qemu-img: Check post-truncation size iotests: Add test for COR across nodes iotests: Copy 197 for COR filter driver iotests: Clean up wrap image in 197 block: Support BDRV_REQ_WRITE_UNCHANGED in filters block/quorum: Support BDRV_REQ_WRITE_UNCHANGED block: Set BDRV_REQ_WRITE_UNCHANGED for COR writes block: Add BDRV_REQ_WRITE_UNCHANGED flag block: BLK_PERM_WRITE includes ..._UNCHANGED block: Add COR filter driver iotests: Skip 181 and 201 without userfaultfd iotests: Add failure matching to common.qemu docs: Document the new default sizes of the qcow2 caches qcow2: Give the refcount cache the minimum possible size by default specs/qcow2: Clarify that compressed clusters have the COPIED bit reset Fix error message about compressed clusters with OFLAG_COPIED ... Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-05-15iotests: Add test for -U/force-share conflictsMax Reitz2-0/+33
Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20180502202051.15493-4-mreitz@redhat.com Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15qemu-img: Use only string options in img_open_optsMax Reitz1-2/+2
img_open_opts() takes a QemuOpts and converts them to a QDict, so all values therein are strings. Then it may try to call qdict_get_bool(), however, which will fail with a segmentation fault every time: $ ./qemu-img info -U --image-opts \ driver=file,filename=/dev/null,force-share=off [1] 27869 segmentation fault (core dumped) ./qemu-img info -U --image-opts driver=file,filename=/dev/null,force-share=off Fix this by using qdict_get_str() and comparing the value as a string. Also, when adding a force-share value to the QDict, add it as a string so it fits the rest of the dict. Cc: qemu-stable@nongnu.org Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20180502202051.15493-3-mreitz@redhat.com Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15qemu-io: Use purely string blockdev optionsMax Reitz1-2/+2
Currently, qemu-io only uses string-valued blockdev options (as all are converted directly from QemuOpts) -- with one exception: -U adds the force-share option as a boolean. This in itself is already a bit questionable, but a real issue is that it also assumes the value already existing in the options QDict would be a boolean, which is wrong. That has the following effect: $ ./qemu-io -r -U --image-opts \ driver=file,filename=/dev/null,force-share=off [1] 15200 segmentation fault (core dumped) ./qemu-io -r -U --image-opts driver=file,filename=/dev/null,force-share=off Since @opts is converted from QemuOpts, the value must be a string, and we have to compare it as such. Consequently, it makes sense to also set it as a string instead of a boolean. Cc: qemu-stable@nongnu.org Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20180502202051.15493-2-mreitz@redhat.com Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15block: Document BDRV_REQ_WRITE_UNCHANGED supportMax Reitz1-2/+16
Add BDRV_REQ_WRITE_UNCHANGED to the list of flags honored during pwrite and pwrite_zeroes, and also add a note on when you absolutely need to support it. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20180502140359.18222-1-mreitz@redhat.com Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15qemu-img: Check post-truncation sizeMax Reitz1-4/+35
Some block drivers (iscsi and file-posix when dealing with device files) do not actually support truncation, even though they provide a .bdrv_truncate() method and will happily return success when providing a new size that does not exceed the current size. This is because these drivers expect the user to resize the image outside of qemu and then provide qemu with that information through the block_resize command (compare cb1b83e740384b4e0d950f3d7c81c02b8ce86c2e). Of course, anyone using qemu-img resize will find that behavior useless. So we should check the actual size of the image after the supposedly successful truncation took place, emit an error if nothing changed and emit a warning if the target size was not met. Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1523065 Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20180421163957.29872-1-mreitz@redhat.com Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15iotests: Add test for COR across nodesMax Reitz3-0/+144
COR across nodes (that is, you have some filter node between the actually COR target and the node that performs the COR) cannot reliably work together with the permission system when there is no explicit COR node that can request the WRITE_UNCHANGED permission for its child. This is because COR (currently) sneaks its requests by the usual permission checks, so it can work without a WRITE* permission; but if there is a filter node in between, that will re-issue the request, which then passes through the usual check -- and if nobody has requested a WRITE_UNCHANGED permission, that check will fail. There is no real direct fix apart from hoping that there is someone who has requested that permission; in case of just the qemu-io HMP command (and no guest device), however, that is not the case. The real real fix is to implement the copy-on-read flag through an implicitly added COR node. Such a node can request the necessary permissions as shown in this test. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20180421132929.21610-10-mreitz@redhat.com Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15iotests: Copy 197 for COR filter driverMax Reitz3-0/+147
iotest 197 tests copy-on-read using the (now old) copy-on-read flag. Copy it to 215 and modify it to use the COR filter driver instead. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20180421132929.21610-9-mreitz@redhat.com Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15iotests: Clean up wrap image in 197Max Reitz1-0/+1
Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 20180421132929.21610-8-mreitz@redhat.com Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15block: Support BDRV_REQ_WRITE_UNCHANGED in filtersMax Reitz7-14/+28
Update the rest of the filter drivers to support BDRV_REQ_WRITE_UNCHANGED. They already forward write request flags to their children, so we just have to announce support for it. This patch does not cover the replication driver because that currently does not support flags at all, and because it just grabs the WRITE permission for its children when it can, so we should be fine just submitting the incoming WRITE_UNCHANGED requests as normal writes. It also does not cover format drivers for similar reasons. They all use bdrv_format_default_perms() as their .bdrv_child_perm() implementation so they just always grab the WRITE permission for their file children whenever possible. In addition, it often would be difficult to ascertain whether incoming unchanging writes end up as unchanging writes in their files. So we just leave them as normal potentially changing writes. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 20180421132929.21610-7-mreitz@redhat.com Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15block/quorum: Support BDRV_REQ_WRITE_UNCHANGEDMax Reitz1-6/+13
We just need to forward it to quorum's children (except in case of a rewrite because of corruption), but for that we first have to support flags in child requests at all. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 20180421132929.21610-6-mreitz@redhat.com Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15block: Set BDRV_REQ_WRITE_UNCHANGED for COR writesMax Reitz1-2/+4
Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 20180421132929.21610-5-mreitz@redhat.com Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15block: Add BDRV_REQ_WRITE_UNCHANGED flagMax Reitz2-2/+10
This flag signifies that a write request will not change the visible disk content. With this flag set, it is sufficient to have the BLK_PERM_WRITE_UNCHANGED permission instead of BLK_PERM_WRITE. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 20180421132929.21610-4-mreitz@redhat.com Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15block: BLK_PERM_WRITE includes ..._UNCHANGEDMax Reitz1-0/+3
Currently we never actually check whether the WRITE_UNCHANGED permission has been taken for unchanging writes. But the one check that is commented out checks both WRITE and WRITE_UNCHANGED; and considering that WRITE_UNCHANGED is already documented as being weaker than WRITE, we should probably explicitly document WRITE to include WRITE_UNCHANGED. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 20180421132929.21610-3-mreitz@redhat.com Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15block: Add COR filter driverMax Reitz3-2/+176
This adds a simple copy-on-read filter driver. It relies on the already existing COR functionality in the central block layer code, which may be moved here once we no longer need it there. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20180421132929.21610-2-mreitz@redhat.com Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15iotests: Skip 181 and 201 without userfaultfdMax Reitz2-0/+26
userfaultfd support depends on the host kernel, so it may not be available. If so, 181 and 201 should be skipped. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20180406151731.4285-3-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15iotests: Add failure matching to common.qemuMax Reitz1-7/+51
Currently, common.qemu only allows to match for results indicating success. The only way to fail is by provoking a timeout. However, sometimes we do have a defined failure output and can match for that, which saves us from having to wait for the timeout in case of failure. Because failure can sometimes just result in a _notrun in the test, it is actually important to care about being able to fail quickly. Also, sometimes we simply do not get any specific output in case of success. The only way to handle this currently would be to define an error message as the string to look for, which means that actual success results in a timeout. This is really bad because it unnecessarily slows down a succeeding test. Therefore, this patch adds a new parameter $success_or_failure to _timed_wait_for and _send_qemu_cmd. Setting this to a non-empty string makes both commands expect two match parameters: If the first matches, the function succeeds. If the second matches, the function fails. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20180406151731.4285-2-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15docs: Document the new default sizes of the qcow2 cachesAlberto Garcia1-17/+16
We have just reduced the refcount cache size to the minimum unless the user explicitly requests a larger one, so we have to update the documentation to reflect this change. Signed-off-by: Alberto Garcia <berto@igalia.com> Message-id: c5f0bde23558dd9d33b21fffc76ac9953cc19c56.1523968389.git.berto@igalia.com Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15qcow2: Give the refcount cache the minimum possible size by defaultAlberto Garcia3-17/+20
The L2 and refcount caches have default sizes that can be overridden using the l2-cache-size and refcount-cache-size (an additional parameter named cache-size sets the combined size of both caches). Unless forced by one of the aforementioned parameters, QEMU will set the unspecified sizes so that the L2 cache is 4 times larger than the refcount cache. This is based on the premise that the refcount metadata needs to be only a fourth of the L2 metadata to cover the same amount of disk space. This is incorrect for two reasons: a) The amount of disk covered by an L2 table depends solely on the cluster size, but in the case of a refcount block it depends on the cluster size *and* the width of each refcount entry. The 4/1 ratio is only valid with 16-bit entries (the default). b) When we talk about disk space and L2 tables we are talking about guest space (L2 tables map guest clusters to host clusters), whereas refcount blocks are used for host clusters (including L1/L2 tables and the refcount blocks themselves). On a fully populated (and uncompressed) qcow2 file, image size > virtual size so there are more refcount entries than L2 entries. Problem (a) could be fixed by adjusting the algorithm to take into account the refcount entry width. Problem (b) could be fixed by increasing a bit the refcount cache size to account for the clusters used for qcow2 metadata. However this patch takes a completely different approach and instead of keeping a ratio between both cache sizes it assigns as much as possible to the L2 cache and the remainder to the refcount cache. The reason is that L2 tables are used for every single I/O request from the guest and the effect of increasing the cache is significant and clearly measurable. Refcount blocks are however only used for cluster allocation and internal snapshots and in practice are accessed sequentially in most cases, so the effect of increasing the cache is negligible (even when doing random writes from the guest). So, make the refcount cache as small as possible unless the user explicitly asks for a larger one. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 9695182c2eb11b77cb319689a1ebaa4e7c9d6591.1523968389.git.berto@igalia.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15specs/qcow2: Clarify that compressed clusters have the COPIED bit resetAlberto Garcia1-4/+4
Compressed clusters are not supposed to have the COPIED bit set, but this is not made explicit in the specs, so let's document it. Signed-off-by: Alberto Garcia <berto@igalia.com> Message-id: 74552e1d6e858d3159cb0c0e188e80bc9248e337.1523376013.git.berto@igalia.com Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15Fix error message about compressed clusters with OFLAG_COPIEDAlberto Garcia1-2/+2
Compressed clusters are not supposed to have the COPIED bit set. "qemu-img check" detects that and prints an error message reporting the number of the affected host cluster. This doesn't make much sense because compressed clusters are not aligned to host clusters, so it would be better to report the offset instead. Plus, the calculation is wrong and it uses the raw L2 entry as if it was simply an offset. This patch fixes the error message and reports the offset of the compressed cluster. Signed-off-by: Alberto Garcia <berto@igalia.com> Message-id: 0f687957feb72e80c740403191a47e607c2463fe.1523376013.git.berto@igalia.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15iotests: Split 214 off of 122Max Reitz5-80/+133
Commit abd3622cc03cf41ed542126a540385f30a4c0175 added a case to 122 regarding how the qcow2 driver handles an incorrect compressed data length value. This does not really fit into 122, as that file is supposed to contain qemu-img convert test cases, which this case is not. So this patch splits it off into its own file; maybe we will even get more qcow2-only compression tests in the future. Also, that test case does not work with refcount_bits=1, so mark that option as unsupported. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20180406164108.26118-1-mreitz@redhat.com Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-15blockjob: Add block_job_driver()Kevin Wolf3-3/+17
The backup block job directly accesses the driver field in BlockJob. Add a wrapper for getting it. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com>
2018-05-15blockjob: Introduce block_job_ratelimit_get_delay()Kevin Wolf6-19/+29
This gets us rid of more direct accesses to BlockJob fields from the job drivers. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com>
2018-05-15blockjob: Implement block_job_set_speed() centrallyKevin Wolf7-72/+12
All block job drivers support .set_speed and all of them duplicate the same code to implement it. Move that code to blockjob.c and remove the now useless callback. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com>
2018-05-15blockjob: Move RateLimit to BlockJobKevin Wolf5-12/+13
Every block job has a RateLimit, and they all do the exact same thing with it, so it should be common infrastructure. Move the struct field for a start. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com>
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