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2015-11-11block: Make bdrv_states publicMax Reitz
When inserting a BDS tree into a BB, we will need to add the root BDS to this list. Since we will want to do that in the blockdev-insert-medium implementation in blockdev.c, we will need access to it there. This patch is not exactly elegant, but bdrv_states will be removed in the future anyway because we no longer need it since we have BBs. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-11-11block: Don't call blk_bs() twice in bdrv_lookup_bs()Alberto Garcia
Signed-off-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-10-23block: Prepare for NULL BDSMax Reitz
blk_bs() will not necessarily return a non-NULL value any more (unless blk_is_available() is true or it can be assumed to otherwise, e.g. because it is called immediately after a successful blk_new_with_bs() or blk_new_open()). Signed-off-by: Max Reitz <mreitz@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>
2015-10-23block: Move BlockAcctStats into BlockBackendMax Reitz
As the comment above bdrv_get_stats() says, BlockAcctStats is something which belongs to the device instead of each BlockDriverState. This patch therefore moves it into the BlockBackend. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-10-23block: Move guest_block_size into BlockBackendMax Reitz
guest_block_size is a guest device property so it should be moved into the interface between block layer and guest devices, which is the BlockBackend. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-10-23block: Invoke change media CB before NULLing drvMax Reitz
In order to handle host device passthrough, some guest device models may call blk_is_inserted() to check whether the medium is inserted on the host, when checking the guest tray status. This tray status is inquired by blk_dev_change_media_cb(); because bdrv_is_inserted() (invoked by blk_is_inserted()) always returns false for BDS with drv set to NULL, blk_dev_change_media_cb() should therefore be called before drv is set to NULL. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-10-23block: Make bdrv_is_inserted() recursiveMax Reitz
If bdrv_is_inserted() is called on the top level BDS, it should make sure all nodes in the BDS tree are actually inserted. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-10-23block: Make bdrv_is_inserted() return a boolMax Reitz
Make bdrv_is_inserted(), blk_is_inserted(), and the callback BlockDriver.bdrv_is_inserted() return a bool. Suggested-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-10-23block: Set BDRV_O_INCOMING in bdrv_fill_options()Max Reitz
This flag should not be set for the root BDS only, but for any BDS that is being created while incoming migration is pending, so setting it is moved from blockdev_init() to bdrv_fill_options(). Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-10-20coroutine: move into libqemuutil.a libraryDaniel P. Berrange
The coroutine files are currently referenced by the block-obj-y variable. The coroutine functionality though is already used by more than just the block code. eg migration code uses coroutine yield. In the future the I/O channel code will also use the coroutine yield functionality. Since the coroutine code is nicely self-contained it can be easily built as part of the libqemuutil.a library, making it widely available. The headers are also moved into include/qemu, instead of the include/block directory, since they are now part of the util codebase, and the impl was never in the block/ directory either. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-10-16block: auto-generated node-namesJeff Cody
If a node-name is not specified, automatically generate the node-name. Generated node-names will use the "block" sub-system identifier. Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-10-16block: Allow bdrv_unref_child(bs, NULL)Kevin Wolf
bdrv_unref() can be called with a NULL argument and doesn't do anything then. Make bdrv_unref_child() consistent with it. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com>
2015-10-16block: Remove bdrv_swap()Kevin Wolf
bdrv_swap() is unused now. Remove it and all functions that have no other users than bdrv_swap(). In particular, this removes the .bdrv_rebind callbacks from block drivers. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-10-16block: Add and use bdrv_replace_in_backing_chain()Kevin Wolf
This cleans up the mess we left behind in the mirror code after the previous patch. Instead of using bdrv_swap(), just change pointers. The interface change of the mirror job that callers must consider is that after job completion, their local BDS pointers still point to the same node now. qemu-img must change its code accordingly (which makes it easier to understand); the other callers stays unchanged because after completion they don't do anything with the BDS, but just with the job, and the job is still owned by the source BDS. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-10-16block: Implement bdrv_append() without bdrv_swap()Kevin Wolf
Remember all parent nodes and just change the pointers there instead of swapping the contents of the BlockDriverState. Handling of snapshot=on must be moved further down in bdrv_open() because *pbs (which is the bs pointer in the BlockBackend) must already be set before bdrv_append() is called. Otherwise bdrv_append() changes the BB's pointer to the temporary snapshot, but bdrv_open() overwrites it with the read-only original image. We also need to be careful to update callers as the interface changes (becomes less insane): Previously, the meaning of the two parameters was inverted when bdrv_append() returns. Now any BDS pointers keep pointing to the same node. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-10-16block: Introduce parents listKevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-10-16block: Split bdrv_move_feature_fields()Kevin Wolf
After bdrv_swap(), some fields must be moved back to their original BDS to compensate for the effects that a swap of the contents of the objects has while keeping the old addresses. Other fields must be moved back because they should logically be moved and must stay on top When replacing bdrv_swap() with operations changing the pointers in the parents, we only need the latter and must avoid swapping the former. Split the function accordingly. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-10-16block: Manage backing file references in bdrv_set_backing_hd()Kevin Wolf
This simplifies the code somewhat, especially when dropping whole backing file subchains. The exception is the mirroring code that does adventurous things with bdrv_swap() and in order to keep it working, I had to duplicate most of bdrv_set_backing_hd() locally. We'll get rid again of this ugliness shortly. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-10-16block: Convert bs->backing_hd to BdrvChildKevin Wolf
This is the final step in converting all of the BlockDriverState pointers that block drivers use to BdrvChild. After this patch, bs->children contains the full list of child nodes that are referenced by a given BDS, and these children are only referenced through BdrvChild, so that updating the pointer in there is enough for changing edges in the graph. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-10-16block: Remove bdrv_open_image()Kevin Wolf
It is unused now. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-10-16block: Convert bs->file to BdrvChildKevin Wolf
This patch removes the temporary duplication between bs->file and bs->file_child by converting everything to BdrvChild. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-10-16block: Introduce BDS.file_childKevin Wolf
Store the BdrvChild for bs->file. At this point, bs->file_child->bs just duplicates the bs->file pointer. Later, it will completely replace it. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-10-02block: disable I/O limits at the beginning of bdrv_close()Alberto Garcia
Disabling I/O limits from a BDS also drains all pending throttled requests, so it should be done at the beginning of bdrv_close() with the rest of the bdrv_drain() calls before the BlockDriver is closed. Signed-off-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-09-14block: Allow specifying driver-specific options to reopenKevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-09-14block: Drop bdrv_find_whitelisted_format()Max Reitz
It is unused by now, so we can drop it. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-09-14block: Drop drv parameter from bdrv_fill_options()Max Reitz
Now that this parameter is effectively unused, we can drop it and change the function accordingly. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-09-14block: Drop drv parameter from bdrv_open_inherit()Max Reitz
Now that this parameter is effectively unused, we can drop it and just pass NULL to bdrv_fill_options(). Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-09-14block: Drop drv parameter from bdrv_open()Max Reitz
Now that this parameter is effectively unused, we can drop it and just pass NULL on to bdrv_open_inherit(). Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-09-14block: Always pass NULL as drv for bdrv_open()Max Reitz
Change all callers of bdrv_open() to pass the driver name in the options QDict instead of passing its BlockDriver pointer. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-09-11opts: produce valid command line in qemu_opts_printKővágó, Zoltán
This will let us print options in a format that the user would actually write it on the command line (foo=bar,baz=asd,etc=def), without prepending a spurious comma at the beginning of the list, or quoting values unnecessarily. This patch provides the following changes: * write and id=, if the option has an id * do not print separator before the first element * do not quote string arguments * properly escape commas (,) for QEMU Signed-off-by: Kővágó, Zoltán <DirtY.iCE.hu@gmail.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2015-09-02block: more check for replaced nodeWen Congyang
We use mirror+replace to fix quorum's broken child. bs/s->common.bs is quorum, and to_replace is the broken child. The new child is target_bs. Without this patch, the replace node can be any node, and it can be top BDS with BB, or another quorum's child. We just check if the broken child is part of the quorum BDS in this patch. Signed-off-by: Wen Congyang <wency@cn.fujitsu.com> Message-id: 55A86486.1000404@cn.fujitsu.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-07-14block: Fix backing file child when modifying graphKevin Wolf
This patch moves bdrv_attach_child() from the individual places that add a backing file to a BDS to bdrv_set_backing_hd(), which is called by all of them. It also adds bdrv_detach_child() there. For normal operation (starting with one backing file chain and not changing it until the topmost image is closed) and live snapshots, this constitutes no change in behaviour. For all other cases, this is a fix for the bug that the old backing file was still referenced as a child, and the new one wasn't referenced. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-07-14block: Reorder cleanups in bdrv_close()Kevin Wolf
Block drivers may still want to access their child nodes in their .bdrv_close handler. If they unref and/or detach a child by themselves, this should not result in a double free. There is additional code for backing files, which are just a special case of child nodes. The same applies for them. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-07-14block: Introduce bdrv_unref_child()Kevin Wolf
This is the counterpart for bdrv_open_child(). It decreases the reference count of the child BDS and removes it from the list of children of the given parent BDS. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-07-14block: Introduce bdrv_open_child()Kevin Wolf
It is the same as bdrv_open_image(), except that it doesn't only return success or failure, but the newly created BdrvChild object for the new child node. As the BdrvChild object already contains a BlockDriverState pointer (and this is supposed to become the only pointer so that bdrv_append() and friends can just change a single pointer in BdrvChild), the pbs parameter is removed for bdrv_open_child(). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-07-14block: Move bdrv_attach_child() calls up the call chainKevin Wolf
Let the callers of bdrv_open_inherit() call bdrv_attach_child(). It needs to be called in all cases where bdrv_open_inherit() succeeds (i.e. returns 0) and a child_role is given. bdrv_attach_child() is moved upwards to avoid a forward declaration. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-07-07block: Use bdrv_drain to replace uncessary bdrv_drain_allFam Zheng
There callers work on a single BlockDriverState subtree, where using bdrv_drain() is more accurate. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-07-07block: Initialize local_err in bdrv_append_temp_snapshotFam Zheng
Cc: qemu-stable@nongnu.org Signed-off-by: Fam Zheng <famz@redhat.com> Message-id: 1436156684-16526-1-git-send-email-famz@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-07-02block: Remove bdrv_reset_dirtyFam Zheng
Using this function would always be wrong because a dirty bitmap must have a specific owner that consumes the dirty bits and calls bdrv_reset_dirty_bitmap(). Remove the unused function to avoid future misuse. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-06-23block: Use bdrv_is_sg() everywhereDimitris Aragiorgis
Instead of checking bs->sg use bdrv_is_sg() consistently throughout the code. Signed-off-by: Dimitris Aragiorgis <dimara@arrikto.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 1435056300-14924-2-git-send-email-dimara@arrikto.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-06-23util/hbitmap: Add an API to reset all set bits in hbitmapWen Congyang
The function bdrv_clear_dirty_bitmap() is updated to use faster hbitmap_reset_all() call. Signed-off-by: Wen Congyang <wency@cn.fujitsu.com> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com> Signed-off-by: Gonglei <arei.gonglei@huawei.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 555E868A.60506@cn.fujitsu.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: Move #include out of qerror.hMarkus Armbruster
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>
2015-06-15Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into stagingPeter Maydell
Block layer core and image format patches # gpg: Signature made Fri Jun 12 16:08:53 2015 BST using RSA key ID C88F2FD6 # gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" * remotes/kevin/tags/for-upstream: (25 commits) block: Fix reopen flag inheritance block: Add BlockDriverState.inherits_from block: Add list of children to BlockDriverState queue.h: Add QLIST_FIX_HEAD_PTR() block: Drain requests before swapping nodes in bdrv_swap() block: Move flag inheritance to bdrv_open_inherit() block: Use QemuOpts in bdrv_open_common() block: Use macro for cache option names vmdk: Use bdrv_open_image() quorum: Use bdrv_open_image() check-qdict: Test cases for new functions qdict: Add qdict_{set,copy}_default() qdict: Add qdict_array_entries() iotests: Add tests for overriding BDRV_O_PROTOCOL block: driver should override flags in bdrv_open() block: Change bitmap truncate conditional to assertion block: record new size in bdrv_dirty_bitmap_truncate raw-posix: Fix .bdrv_co_get_block_status() for unaligned image size vmdk: Use vmdk_find_index_in_cluster everywhere vmdk: Fix index_in_cluster calculation in vmdk_co_get_block_status ... Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2015-06-12block: Fix reopen flag inheritanceKevin Wolf
When reopening an image, the block layer already takes care to reopen bs->file as well with recalculated inherited flags. The same must happen for any other child (most notably missing before this patch: backing files). If bs->file (or any other child) didn't originally inherit from bs, e.g. because it was created separately and then only referenced, it must not inherit flags on reopen either, so check the inherited_from field before propagation the reopen down. VMDK already reopened its extents manually; this code can now be dropped. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-06-12block: Add BlockDriverState.inherits_fromKevin Wolf
Currently, the block layer assumes that any block node can have only one parent, and if it has a parent, that it inherits some options/flags from this parent. This is not true any more: With references used in block device creation, a single node can be used by multiple parents, or it can be created separately and not inherit flags from any parent. To handle reopens correctly, a node must know from which parent it inherited options. This patch adds the information to BlockDriverState. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-06-12block: Add list of children to BlockDriverStateKevin Wolf
This allows iterating over all children of a given BDS, not only including bs->file and bs->backing_hd, but also driver-specific ones like VMDK extents or Quorum children. For bdrv_swap(), the list of children of the swapped BDS stays at that BDS (because that's where the pointers stay as well). The list head moves and pointers to it must be fixed up therefore. The list of children in the parent of the swapped BDS is not affected by the swap. The contents of the BDS objects is swapped, so the existing pointer in the parent automatically points to the newly swapped in BDS. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-06-12block: Drain requests before swapping nodes in bdrv_swap()Kevin Wolf
bdrv_swap() requires that there are no requests in flight on either of the two devices. The request coroutine would work on the wrong BlockDriverState object (with bs->opaque even being interpreted as a different type potentially) and all sorts of bad things would result from this. The currently existing callers mostly ensure that there is no I/O pending on nodes that are swapped. In detail, this is: 1. Live snapshots. This goes through qmp_transaction(), which calls bdrv_drain_all() before doing anything. The command is executed synchronously, so no new I/O can be issued concurrently. 2. snapshot=on in bdrv_open(). We're in the middle of opening the image (both the original image and its temporary overlay), so there can't be any I/O in flight yet. 3. Mirroring. bdrv_drain() is already used on the source device so that the mirror doesn't miss anything. However, the main loop runs between that and the bdrv_swap() (which is actually a bug, being addressed in another series), so there is a small window in which new I/O might be issued that would be in flight during bdrv_swap(). It is safer to just drain the request queue of both devices in bdrv_swap() instead of relying on callers to do the right thing. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>