- 24 2月, 2017 5 次提交
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由 Kevin Wolf 提交于
This is a function that doesn't do any option parsing, but just does some basic BlockDriverState setup and calls the .bdrv_open() function of the block driver. Signed-off-by: NKevin Wolf <kwolf@redhat.com> Reviewed-by: NMax Reitz <mreitz@redhat.com>
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由 Kevin Wolf 提交于
This fixes the use of a parent-less BdrvChild in bdrv_open_inherit() by converting it into a BlockBackend. Which is exactly what it should be, image probing is an external, standalone user of a node. The requests can't be considered to originate from the format driver node because that one isn't even opened yet. Signed-off-by: NKevin Wolf <kwolf@redhat.com> Reviewed-by: NMax Reitz <mreitz@redhat.com>
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由 Kevin Wolf 提交于
This is the part of bdrv_open_child() that opens a BDS with option inheritance, but doesn't attach it as a child to the parent yet. Signed-off-by: NKevin Wolf <kwolf@redhat.com> Reviewed-by: NMax Reitz <mreitz@redhat.com>
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由 Kevin Wolf 提交于
The way that attaching bs->file worked was a bit unusual in that it was the only child that would be attached to a node which is not opened yet. Because of this, the block layer couldn't know yet which permissions the driver would eventually need. This patch moves the point where bs->file is attached to the beginning of the individual .bdrv_open() implementations, so drivers already know what they are going to do with the child. This is also more consistent with how driver-specific children work. For a moment, bdrv_open() gets its own BdrvChild to perform image probing, but instead of directly assigning this BdrvChild to the BDS, it becomes a temporary one and the node name is passed as an option to the drivers, so that they can simply use bdrv_open_child() to create another reference for their own use. This duplicated child for (the not opened yet) bs is not the final state, a follow-up patch will change the image probing code to use a BlockBackend, which is completely independent of bs. Signed-off-by: NKevin Wolf <kwolf@redhat.com> Reviewed-by: NMax Reitz <mreitz@redhat.com>
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由 Kevin Wolf 提交于
Signed-off-by: NKevin Wolf <kwolf@redhat.com> Reviewed-by: NMax Reitz <mreitz@redhat.com>
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- 12 2月, 2017 2 次提交
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Current implementation invalidates firstly parent bds and then its children. This leads to the following bug: after incoming migration, in bdrv_invalidate_cache_all: 1. invalidate parent bds - reopen it with BDRV_O_INACTIVE cleared 2. child is not yet invalidated 3. parent check that its BDRV_O_INACTIVE is cleared 4. parent writes to child 5. assert in bdrv_co_pwritev, as BDRV_O_INACTIVE is set for child This patch fixes it by just changing invalidate sequence: invalidate children first. Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20170131112308.54189-1-vsementsov@virtuozzo.com Reviewed-by: NMax Reitz <mreitz@redhat.com> Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com> Signed-off-by: NMax Reitz <mreitz@redhat.com>
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由 Jeff Cody 提交于
In bdrv_find_backing_image(), if we are searching an image for a backing file that contains a protocol, we currently only compare unmodified paths. However, some management software will change the backing filename to be a relative filename in a path. QEMU is able to handle this fine, because internally it will use path_combine to put together the full protocol URI. However, this can lead to an inability to match an image during a QAPI command that needs to use bdrv_find_backing_image() to find the image, when it is searched by the full URI. When searching for a protocol filename, if the straight comparison fails, this patch will also compare against the full backing filename to see if that is a match. Signed-off-by: NJeff Cody <jcody@redhat.com> Message-id: c2d025adca8a2b665189e6f4cf080f44126d0b6b.1485392617.git.jcody@redhat.com Reviewed-by: NMax Reitz <mreitz@redhat.com> Signed-off-by: NMax Reitz <mreitz@redhat.com>
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- 01 2月, 2017 1 次提交
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由 Daniel P. Berrange 提交于
Introduce rules in the top level Makefile that are able to generate trace.[ch] files in every subdirectory which has a trace-events file. The top level directory is handled specially, so instead of creating trace.h, it creates trace-root.h. This allows sub-directories to include the top level trace-root.h file, without ambiguity wrt to the trace.g file in the current sub-dir. Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com> Signed-off-by: NDaniel P. Berrange <berrange@redhat.com> Message-id: 20170125161417.31949-7-berrange@redhat.com Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
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- 25 1月, 2017 1 次提交
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由 Paolo Bonzini 提交于
options must be non-NULL here, because a NULL value is replaced with qdict_new earlier in the function. Reported by Coverity. Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com> Reviewed-by: NEric Blake <eblake@redhat.com> Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>
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- 11 11月, 2016 2 次提交
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由 Max Reitz 提交于
Some block drivers may not be loaded yet, but qemu supports them nonetheless. bdrv_iterate_format() should report them, too. Signed-off-by: NMax Reitz <mreitz@redhat.com> Message-id: 20161012204907.25941-3-mreitz@redhat.com Reviewed-by: NEric Blake <eblake@redhat.com> Signed-off-by: NMax Reitz <mreitz@redhat.com>
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由 Max Reitz 提交于
bdrv_iterate_format() did not actually sort the formats by name but by "pointer interpreted as string". That is probably not what we intended to do, so fix it (by changing qsort_strcmp() so it matches the example from qsort()'s manual page). Signed-off-by: NMax Reitz <mreitz@redhat.com> Message-id: 20161012204907.25941-2-mreitz@redhat.com Reviewed-by: NEric Blake <eblake@redhat.com> Signed-off-by: NMax Reitz <mreitz@redhat.com>
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- 31 10月, 2016 2 次提交
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由 Alberto Garcia 提交于
This makes sure that the image we are streaming into is open in read-write mode during the operation. Operation blockers are also set in all intermediate nodes, since they will be removed from the chain afterwards. Finally, this also unblocks the stream operation in backing files. Signed-off-by: NAlberto Garcia <berto@igalia.com> Reviewed-by: NKevin Wolf <kwolf@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Alberto Garcia 提交于
When a BlockDriverState is about to be reopened it can trigger certain operations that need to write to disk. During this process a different block job can be woken up. If that block job completes and also needs to call bdrv_reopen() it can happen that it needs to do it on the same BlockDriverState that is still in the process of being reopened. This can have fatal consequences, like in this example: 1) Block job A starts and sleeps after a while. 2) Block job B starts and tries to reopen node1 (a qcow2 file). 3) Reopening node1 means flushing and replacing its qcow2 cache. 4) While the qcow2 cache is being flushed, job A wakes up. 5) Job A completes and reopens node1, replacing its cache. 6) Job B resumes, but the cache that was being flushed no longer exists. This patch splits the bdrv_drain_all() call to keep all block jobs paused during bdrv_reopen_multiple(), so that step 4 can never happen and the operation is safe. Note that this scenario can only happen if both bdrv_reopen() calls are made by block jobs on the same backing chain. Otherwise there's no chance that the same BlockDriverState appears in both reopen queues. Signed-off-by: NAlberto Garcia <berto@igalia.com> Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com> Reviewed-by: NKevin Wolf <kwolf@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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- 28 10月, 2016 2 次提交
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由 Paolo Bonzini 提交于
aio_poll is not thread safe; for example bdrv_drain can hang if the last in-flight I/O operation is completed in the I/O thread after the main thread has checked bs->in_flight. The bug remains latent as long as all of it is called within aio_context_acquire/aio_context_release, but this will change soon. To fix this, if bdrv_drain is called from outside the I/O thread, signal the main AioContext through a dummy bottom half. The event loop then only runs in the I/O thread. Reviewed-by: NFam Zheng <famz@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com> Message-Id: <1477565348-5458-18-git-send-email-pbonzini@redhat.com> Signed-off-by: NFam Zheng <famz@redhat.com>
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由 Paolo Bonzini 提交于
After the next patch bdrv_drain_all will have to be called without holding any AioContext. Prepare to do this by adding an AioContext argument to bdrv_reopen_multiple. Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com> Reviewed-by: NFam Zheng <famz@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com> Message-Id: <1477565348-5458-15-git-send-email-pbonzini@redhat.com> Signed-off-by: NFam Zheng <famz@redhat.com>
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- 07 10月, 2016 2 次提交
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由 Kevin Wolf 提交于
The event currently only contains the BlockBackend name. However, with anonymous BlockBackends, this is always the empty string. Add the qdev ID (or if none was given, the QOM path) so that the user can still see which device caused the event. Event generation has to be moved from bdrv_eject() to the BlockBackend because the BDS doesn't know the attached device, but that's easy because blk_eject() is the only user of it. Signed-off-by: NKevin Wolf <kwolf@redhat.com> Reviewed-by: NMax Reitz <mreitz@redhat.com>
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由 Kevin Wolf 提交于
Recently we moved a few options from QemuOptsLists in blockdev.c to bdrv_runtime_opts in block.c in order to make them accissble using blockdev-add. However, this has the side effect that these options are missing from query-command-line-options now, and libvirt consequently disables the corresponding feature. This problem was reported as a regression for the 'discard' option, introduced in commit 818584a4. However, it is more general than that. Fix it by adding bdrv_runtime_opts to the list of QemuOptsLists that are returned in query-command-line-options. For the future, libvirt is advised to use QMP schema introspection for block device options. Reported-by: NMichal Privoznik <mprivozn@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com> Tested-by: NMichal Privoznik <mprivozn@redhat.com> Tested-by: NGerd Hoffmann <kraxel@redhat.com>
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- 29 9月, 2016 2 次提交
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由 Kevin Wolf 提交于
This enables its use for nested child nodes. The compatibility between the 'discard' and 'detect-zeroes' setting is checked in bdrv_open_common() now as the former setting isn't available before calling bdrv_open() any more. Signed-off-by: NKevin Wolf <kwolf@redhat.com> Reviewed-by: NEric Blake <eblake@redhat.com> Reviewed-by: NMax Reitz <mreitz@redhat.com>
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由 Kevin Wolf 提交于
Amongst others, this means that you can now use the 'detect-zeroes' option for non-top-level nodes in blockdev-add, like the QAPI schema promises. Signed-off-by: NKevin Wolf <kwolf@redhat.com> Reviewed-by: NEric Blake <eblake@redhat.com> Reviewed-by: NMax Reitz <mreitz@redhat.com>
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- 23 9月, 2016 5 次提交
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由 Alberto Garcia 提交于
bdrv_reopen_queue_child() assumes that a BlockDriverState is never added twice to BlockReopenQueue. That's however not the case: commit_start() adds 'base' (and its children) to a new reopen queue, and then 'overlay_bs' (and its children, which include 'base') to the same queue. The effect of this is that the first set of options is ignored and overriden by the second. We fixed this by swapping the order in which both BDSs were added to the queue in 3db2bd55. This patch checks if a BDS is already in the reopen queue and keeps its options. Signed-off-by: NAlberto Garcia <berto@igalia.com> Reviewed-by: NKevin Wolf <kwolf@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Alberto Garcia 提交于
This adds the "read-only" option to the QDict. One important effect of this change is that when a child inherits options from its parent, the existing "read-only" mode can be preserved if it was explicitly set previously. This addresses scenarios like this: [E] <- [D] <- [C] <- [B] <- [A] In this case, if we reopen [D] with read-only=off, and later reopen [B], then [D] will not inherit read-only=on from its parent during the bdrv_reopen_queue_child() stage. The BDRV_O_RDWR flag is not removed yet, but its keep in sync with the value of the "read-only" option. Signed-off-by: NAlberto Garcia <berto@igalia.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Alberto Garcia 提交于
We're only doing this immediately before opening the image, but bs->open_flags is used earlier in the function. At the moment this is not causing problems because none of the checked flags are modified by update_flags_from_options(), but this will change when we introduce the "read-only" option. This patch calls update_flags_from_options() at the beginning of the function, immediately after creating the QemuOpts. Signed-off-by: NAlberto Garcia <berto@igalia.com> Reviewed-by: NKevin Wolf <kwolf@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Alberto Garcia 提交于
If an image is opened with snapshot=on, its flags are modified by bdrv_backing_options() and then bs->open_flags is updated accordingly. This last step is unnecessary if we calculate the new flags before setting bs->open_flags. Soon we'll introduce the "read-only" option, and then we'll need to be able to modify its value in the QDict when snapshot=on. This is more cumbersome if bs->options is already set. This patch simplifies that. Other than that, there are no semantic changes. Although it might seem that bs->options can have a different value now because it is stored after calling bdrv_backing_options(), this call doesn't actually modify them in this scenario. The code that sets BDRV_O_ALLOW_RDWR is also moved for the same reason. Signed-off-by: NAlberto Garcia <berto@igalia.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Alberto Garcia 提交于
This is unnecessary and has been unused since 5433c24f. Signed-off-by: NAlberto Garcia <berto@igalia.com> Reviewed-by: NKevin Wolf <kwolf@redhat.com> Reviewed-by: NEric Blake <eblake@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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- 21 9月, 2016 1 次提交
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由 Marc Mari 提交于
Extend the current module interface to allow for block drivers to be loaded dynamically on request. The only block drivers that can be converted into modules are the drivers that don't perform any init operation except for registering themselves. In addition, only the protocol drivers are being modularized, as they are the only ones which see significant performance benefits. The format drivers do not generally link to external libraries, so modularizing them is of no benefit from a performance perspective. All the necessary module information is located in a new structure found in module_block.h This spoils the purpose of 5505e8b7 (block/dmg: make it modular). Before this patch, if module build is enabled, block-dmg.so is linked to libbz2, whereas the main binary is not. In downstream, theoretically, it means only the qemu-block-extra package depends on libbz2, while the main QEMU package needn't to. With this patch, we (temporarily) change the case so that the main QEMU depends on libbz2 again. Signed-off-by: NMarc Marí <markmb@redhat.com> Signed-off-by: NColin Lord <clord@redhat.com> Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com> Message-id: 1471008424-16465-4-git-send-email-clord@redhat.com Reviewed-by: NMax Reitz <mreitz@redhat.com> [mreitz: Do a signed comparison against the length of block_driver_modules[], so it will not cause a compile error when empty] Signed-off-by: NMax Reitz <mreitz@redhat.com>
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- 13 9月, 2016 1 次提交
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由 Wen Congyang 提交于
Signed-off-by: NWen Congyang <wency@cn.fujitsu.com> Signed-off-by: NChanglong Xie <xiecl.fnst@cn.fujitsu.com> Signed-off-by: NWang WeiWei <wangww.fnst@cn.fujitsu.com> Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com> Kashyap Chamarthy <kchamart@redhat.com> Message-id: 1469602913-20979-2-git-send-email-xiecl.fnst@cn.fujitsu.com Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
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- 06 9月, 2016 1 次提交
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由 Kevin Wolf 提交于
The builtin NBD server uses its own BlockBackend now instead of reusing the monitor/guest device one. This means that it has its own writethrough setting now. The builtin NBD server always uses writeback caching now regardless of whether the guest device has WCE enabled. qemu-nbd respects the cache mode given on the command line. We still need to keep a reference to the monitor BB because we put an eject notifier on it, but we don't use it for any I/O. Signed-off-by: NKevin Wolf <kwolf@redhat.com> Reviewed-by: NEric Blake <eblake@redhat.com> Reviewed-by: NMax Reitz <mreitz@redhat.com>
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- 20 7月, 2016 1 次提交
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由 Denis V. Lunev 提交于
All .bdrv_co_write_zeroes callbacks nowadays work perfectly even with backing store attached. If future new callbacks would be unable to do that - they have a chance to block this in bdrv_get_info(). Signed-off-by: NDenis V. Lunev <den@openvz.org> Reviewed-by: NEric Blake <eblake@redhat.com> Reviewed-by: NJohn Snow <jsnow@redhat.com> Reviewed-by: NFam Zheng <famz@redhat.com> Message-id: 1468503209-19498-6-git-send-email-den@openvz.org CC: Stefan Hajnoczi <stefanha@redhat.com> CC: Kevin Wolf <kwolf@redhat.com> CC: Max Reitz <mreitz@redhat.com> CC: Jeff Cody <jcody@redhat.com> Signed-off-by: NJeff Cody <jcody@redhat.com>
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- 19 7月, 2016 1 次提交
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由 Evgeny Yakovlev 提交于
Some guests (win2008 server for example) do a lot of unnecessary flushing when underlying media has not changed. This adds additional overhead on host when calling fsync/fdatasync. This change introduces a write generation scheme in BlockDriverState. Current write generation is checked against last flushed generation to avoid unnessesary flushes. The problem with excessive flushing was found by a performance test which does parallel directory tree creation (from 2 processes). Results improved from 0.424 loops/sec to 0.432 loops/sec. Each loop creates 10^3 directories with 10 files in each. This affected some blkdebug testcases that were expecting error logs from failure-injected flushes which are now skipped entirely (tests 026 071 089). This also affects the performance of block jobs and thus BLOCK_JOB_READY events for driver-mirror and active block-commit commands now arrives faster, before QMP send successfully returns to caller (tests 141 144). Signed-off-by: NEvgeny Yakovlev <eyakovlev@virtuozzo.com> Signed-off-by: NDenis V. Lunev <den@openvz.org> Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com> Message-id: 1468870792-7411-5-git-send-email-den@openvz.org CC: Kevin Wolf <kwolf@redhat.com> CC: Max Reitz <mreitz@redhat.com> CC: Stefan Hajnoczi <stefanha@redhat.com> CC: Fam Zheng <famz@redhat.com> CC: John Snow <jsnow@redhat.com> Signed-off-by: NJohn Snow <jsnow@redhat.com>
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- 13 7月, 2016 1 次提交
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由 Paolo Bonzini 提交于
In practice the entry argument is always known at creation time, and it is confusing that sometimes qemu_coroutine_enter is used with a non-NULL argument to re-enter a coroutine (this happens in block/sheepdog.c and tests/test-coroutine.c). So pass the opaque value at creation time, for consistency with e.g. aio_bh_new. Mostly done with the following semantic patch: @ entry1 @ expression entry, arg, co; @@ - co = qemu_coroutine_create(entry); + co = qemu_coroutine_create(entry, arg); ... - qemu_coroutine_enter(co, arg); + qemu_coroutine_enter(co); @ entry2 @ expression entry, arg; identifier co; @@ - Coroutine *co = qemu_coroutine_create(entry); + Coroutine *co = qemu_coroutine_create(entry, arg); ... - qemu_coroutine_enter(co, arg); + qemu_coroutine_enter(co); @ entry3 @ expression entry, arg; @@ - qemu_coroutine_enter(qemu_coroutine_create(entry), arg); + qemu_coroutine_enter(qemu_coroutine_create(entry, arg)); @ reentry @ expression co; @@ - qemu_coroutine_enter(co, NULL); + qemu_coroutine_enter(co); except for the aforementioned few places where the semantic patch stumbled (as expected) and for test_co_queue, which would otherwise produce an uninitialized variable warning. Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com> Reviewed-by: NFam Zheng <famz@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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- 05 7月, 2016 5 次提交
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由 Kevin Wolf 提交于
Signed-off-by: NKevin Wolf <kwolf@redhat.com> Reviewed-by: NMax Reitz <mreitz@redhat.com> Acked-by: NStefan Hajnoczi <stefanha@redhat.com>
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由 Kevin Wolf 提交于
No code changes, just moved from one file to another. Signed-off-by: NKevin Wolf <kwolf@redhat.com> Reviewed-by: NEric Blake <eblake@redhat.com> Acked-by: NStefan Hajnoczi <stefanha@redhat.com>
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由 Eric Blake 提交于
Using int for values that are only used as booleans is confusing. While at it, rearrange a couple of members so that all the bools are contiguous. Signed-off-by: NEric Blake <eblake@redhat.com> Reviewed-by: NFam Zheng <famz@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
It makes more sense to have ALL block size limit constraints in the same struct. Improve the documentation while at it. Simplify a couple of conditionals, now that we have audited and documented that request_alignment is always non-zero. Signed-off-by: NEric Blake <eblake@redhat.com> Reviewed-by: NFam Zheng <famz@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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由 Eric Blake 提交于
We want to eventually stick request_alignment alongside other BlockLimits, but first, we must ensure it is populated at the same time as all other limits, rather than being a special case that is set only when a block is first opened. Now that all drivers have been updated to supply an override of request_alignment during their .bdrv_refresh_limits(), as needed, the block layer itself can defer setting the default alignment until part of the overall bdrv_refresh_limits(). Signed-off-by: NEric Blake <eblake@redhat.com> Reviewed-by: NKevin Wolf <kwolf@redhat.com> Reviewed-by: NFam Zheng <famz@redhat.com> Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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- 20 6月, 2016 2 次提交
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由 Eduardo Habkost 提交于
error_propagate() already ignores local_err==NULL, so there's no need to check it before calling. Coccinelle patch used to perform the changes added to scripts/coccinelle/error_propagate_null.cocci. Reviewed-by: NEric Blake <eblake@redhat.com> Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com> Reviewed-by: NMarkus Armbruster <armbru@redhat.com> Signed-off-by: NEduardo Habkost <ehabkost@redhat.com> Message-Id: <1465855078-19435-2-git-send-email-ehabkost@redhat.com> Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
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由 Stefan Hajnoczi 提交于
It's possible that an AioContext notifier user was close to finishing when .detach_aio_context() or .attached_aio_context() is called. In that case they may call bdrv_remove_aio_context_notifier() during the callback. Use safe iteration to avoid crashing when the notifier list is modified during iteration. We must not only handle the case where the current aio notifier is removed during a callback but also the one where any other aio notifier is removed. The next patch adds an AioContext notifier for block jobs and they really could be terminating just as .detach_aio_context() is invoked. Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com> Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com> Reviewed-by: NFam Zheng <famz@redhat.com> Message-id: 1466096189-6477-6-git-send-email-stefanha@redhat.com
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- 16 6月, 2016 3 次提交
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由 Max Reitz 提交于
Currently, we are trying to move the backing BDS from the source to the target in bdrv_replace_in_backing_chain() which is called from mirror_exit(). However, mirror_complete() already tries to open the target's backing chain with a call to bdrv_open_backing_file(). First, we should only set the target's backing BDS once. Second, the mirroring block job has a better idea of what to set it to than the generic code in bdrv_replace_in_backing_chain() (in fact, the latter's conditions on when to move the backing BDS from source to target are not really correct). Therefore, remove that code from bdrv_replace_in_backing_chain() and leave it to mirror_complete(). Depending on what kind of mirroring is performed, we furthermore want to use different strategies to open the target's backing chain: - If blockdev-mirror is used, we can assume the user made sure that the target already has the correct backing chain. In particular, we should not try to open a backing file if the target does not have any yet. - If drive-mirror with mode=absolute-paths is used, we can and should reuse the already existing chain of nodes that the source BDS is in. In case of sync=full, no backing BDS is required; with sync=top, we just link the source's backing BDS to the target, and with sync=none, we use the source BDS as the target's backing BDS. We should not try to open these backing files anew because this would lead to two BDSs existing per physical file in the backing chain, and we would like to avoid such concurrent access. - If drive-mirror with mode=existing is used, we have to use the information provided in the physical image file which means opening the target's backing chain completely anew, just as it has been done already. If the target's backing chain shares images with the source, this may lead to multiple BDSs per physical image file. But since we cannot reliably ascertain this case, there is nothing we can do about it. Signed-off-by: NMax Reitz <mreitz@redhat.com> Message-id: 20160610185750.30956-3-mreitz@redhat.com Reviewed-by: NKevin Wolf <kwolf@redhat.com> Reviewed-by: NFam Zheng <famz@redhat.com> Signed-off-by: NMax Reitz <mreitz@redhat.com>
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由 Max Reitz 提交于
change_parent_backing_link() asserts that the BDS to be replaced is not used as a backing file. However, we may want to replace a BDS by its overlay in which case that very link should not be redirected. For instance, when doing a sync=none drive-mirror operation, we may have the following BDS/BB forest before block job completion: target base <- source <- BlockBackend During job completion, we want to establish the source BDS as the target's backing node: target | v base <- source <- BlockBackend This makes the target a valid replacement for the source: target <- BlockBackend | v base <- source Without this modification to change_parent_backing_link() we have to inject the target into the graph before the source is its backing node, thus temporarily creating a wrong graph: target <- BlockBackend base <- source Signed-off-by: NMax Reitz <mreitz@redhat.com> Message-id: 20160610185750.30956-2-mreitz@redhat.com Reviewed-by: NKevin Wolf <kwolf@redhat.com> Reviewed-by: NFam Zheng <famz@redhat.com> Signed-off-by: NMax Reitz <mreitz@redhat.com>
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由 Kevin Wolf 提交于
snapshot=on creates a temporary overlay that is always opened with cache=unsafe (the cache mode specified by the user is only for the actual image file and its children). This means that we must not inherit the BDRV_O_NATIVE_AIO flag for the temporary overlay because trying to use Linux AIO with cache=unsafe results in an error. Reproducer without this patch: $ x86_64-softmmu/qemu-system-x86_64 -drive file=/tmp/test.qcow2,cache=none,aio=native,snapshot=on qemu-system-x86_64: -drive file=/tmp/test.qcow2,cache=none,aio=native,snapshot=on: aio=native was specified, but it requires cache.direct=on, which was not specified. Signed-off-by: NKevin Wolf <kwolf@redhat.com>
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