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2016-07-12scsi-bus: Add SCSI scanner supportJarkko Lavinen
Add support for missing scanner specific SCSI commands and their xfer lenghts as per ANSI spec section 15. Signed-off-by: Jarkko Lavinen <jarkko.lavinen@iki.fi> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-05block: Convert bdrv_co_preadv/pwritev to BdrvChildKevin Wolf
This is the final patch for converting the common I/O path to take a BdrvChild parameter instead of BlockDriverState. The completion of this conversion means that all users that perform I/O on an image need to actually hold a reference (in the form of BdrvChild, possible as part of a BlockBackend) to that image. This also protects against inconsistent use of BlockBackend vs. BlockDriverState functions because direct use of a BlockDriverState isn't possible any more and blk->root is private for block-backends.c. In addition, we can now distinguish different users in the I/O path, and the future op blockers work is going to add assertions based on permissions stored in BdrvChild. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-05block: Convert bdrv_pwrite_zeroes() to BdrvChildKevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-05block: Convert bdrv_pwrite(v/_sync) to BdrvChildKevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-05block: Convert bdrv_pread(v) to BdrvChildKevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-05block: Convert bdrv_write() to BdrvChildKevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-05block: Convert bdrv_read() to BdrvChildKevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-05block: Convert bdrv_aio_writev() to BdrvChildKevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-05block: Convert bdrv_aio_readv() to BdrvChildKevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-05block: Convert bdrv_co_writev() to BdrvChildKevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-05block: Convert bdrv_co_readv() to BdrvChildKevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-05block: Use bool as appropriate for BDS membersEric Blake
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: Eric Blake <eblake@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-07-05block: Move request_alignment into BlockLimitEric Blake
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: Eric Blake <eblake@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-07-05block: Switch discard length bounds to byte-basedEric Blake
Sector-based limits are awkward to think about; in our on-going quest to move to byte-based interfaces, convert max_discard and discard_alignment. Rename them, using 'pdiscard' as an aid to track which remaining discard interfaces need conversion, and so that the compiler will help us catch the change in semantics across any rebased code. The BlockLimits type is now completely byte-based; and in iscsi.c, sector_limits_lun2qemu() is no longer needed. pdiscard_alignment is made unsigned (we use power-of-2 alignments as bitmasks, where unsigned is easier to think about) while leaving max_pdiscard signed (since we still have an 'int' interface); this is comparable to what commit cf081fc did for write zeroes limits. We may later want to make everything an unsigned 64-bit limit - but that requires a bigger code audit. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-07-05block: Wording tweaks to write zeroes limitsEric Blake
Improve the documentation of the write zeroes limits, to mention additional constraints that drivers should observe. Worth squashing into commit cf081fca, if that hadn't been pushed already :) Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-07-05block: Switch transfer length bounds to byte-basedEric Blake
Sector-based limits are awkward to think about; in our on-going quest to move to byte-based interfaces, convert max_transfer_length and opt_transfer_length. Rename them (dropping the _length suffix) so that the compiler will help us catch the change in semantics across any rebased code, and improve the documentation. Use unsigned values, so that we don't have to worry about negative values and so that bit-twiddling is easier; however, we are still constrained by 2^31 of signed int in most APIs. When a value comes from an external source (iscsi and raw-posix), sanitize the results to ensure that opt_transfer is a power of 2. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-07-05nbd: Allow larger requestsEric Blake
The NBD layer was breaking up request at a limit of 2040 sectors (just under 1M) to cater to old qemu-nbd. But the server limit was raised to 32M in commit 2d8214885 to match the kernel, more than three years ago; and the upstream NBD Protocol is proposing documentation that without any explicit communication to state otherwise, a client should be able to safely assume that a 32M transaction will work. It is time to rely on the larger sizing, and any downstream distro that cares about maximum interoperability to older qemu-nbd servers can just tweak the value of #define NBD_MAX_SECTORS. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Cc: qemu-stable@nongnu.org Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-06-20blockjob: add AioContext attached callbackStefan Hajnoczi
Block jobs that use additional BDSes or event loop resources need a callback to get their affairs in order when the AioContext is switched. Simple block jobs don't need an attach callback, they automatically work thanks to the generic attach/detach notifiers that this patch adds. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 1466096189-6477-7-git-send-email-stefanha@redhat.com
2016-06-20block: use safe iteration over AioContext notifiersStefan Hajnoczi
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: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 1466096189-6477-6-git-send-email-stefanha@redhat.com
2016-06-20blockjob: add pause pointsStefan Hajnoczi
Block jobs are coroutines that usually perform I/O but sometimes also sleep or yield. Currently only sleeping or yielded block jobs can be paused. This means jobs that do not sleep or yield (using block_job_yield()) are unaffected by block_job_pause(). Add block_job_pause_point() so that block jobs can mark quiescent points that are suitable for pausing. This solves the problem that it can take a block job a long time to pause if it is performing a long series of I/O operations. Transitioning to paused state involves a .pause()/.resume() callback. These callbacks are used to ensure that I/O and event loop activity has ceased while the job is at a pause point. Note that this patch introduces a stricter pause state than previously. The job->busy flag was incorrectly documented as a quiescent state without I/O pending. This is violated by any job that has I/O pending across sleep or block_job_yield(), like the mirror block job. [Add missing block_job_should_pause() check to avoid deadlock after job->driver->pause() in block_job_pause_point(). --Stefan] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 1466096189-6477-4-git-send-email-stefanha@redhat.com
2016-06-20blockjob: rename block_job_is_paused()Stefan Hajnoczi
The block_job_is_paused() function name is not great because callers only use it to determine whether pausing has been requested. Rename it to highlight those semantics and remove it from the public header file as there are no external callers. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 1466096189-6477-3-git-send-email-stefanha@redhat.com
2016-06-16nbd: Avoid magic number for NBD max name sizeEric Blake
Declare a constant and use that when determining if an export name fits within the constraints we are willing to support. Note that upstream NBD recently documented that clients MUST support export names of 256 bytes (not including trailing NUL), and SHOULD support names up to 4096 bytes. 4096 is a bit big (we would lose benefits of stack-allocation of a name array), and we already have other limits in place (for example, qcow2 snapshot names are clamped around 1024). So for now, just stick to the required minimum, as that's easier to audit than a full-scale support for larger names. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1463006384-7734-12-git-send-email-eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16nbd: simplify the nbd_request and nbd_reply structsPaolo Bonzini
These structs are never used to represent the bytes that go over the network. The big-endian network data is built into a uint8_t array in nbd_{receive,send}_{request,reply}. Remove the unused magic field, reorder the struct to avoid holes, and remove the packed attribute. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16block/mirror: Fix target backing BDSMax Reitz
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: Max Reitz <mreitz@redhat.com> Message-id: 20160610185750.30956-3-mreitz@redhat.com Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2016-06-16block: Remove bs->zero_beyond_eofKevin Wolf
It is always true for open images now. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-06-16block: Make bdrv_load/save_vmstate coroutine_fnsKevin Wolf
This allows drivers to share code between normal I/O and vmstate accesses. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-06-16block: Make .bdrv_load_vmstate() vectoredKevin Wolf
This brings it in line with .bdrv_save_vmstate(). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-06-16block: Introduce bdrv_preadv()Kevin Wolf
We already have a byte-based bdrv_pwritev(), but the read counterpart was still missing. This commit adds it. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-06-16block: Byte-based bdrv_co_do_copy_on_readv()Kevin Wolf
In a first step to convert the common I/O path to work on bytes rather than sectors, this converts the copy-on-read logic that is used by bdrv_aligned_preadv(). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-06-16block: Assert that flags are in rangeEric Blake
Add a new BDRV_REQ_MASK constant, and use it to make sure that caller flags are always valid. Tested with 'make check' and with qemu-iotests on both '-raw' and '-qcow2'; the only failure turned up was fixed in the previous commit. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-06-08block: Kill bdrv_co_write_zeroes()Eric Blake
Now that all drivers have been converted to a byte interface, we no longer need a sector interface. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-06-08block: Switch bdrv_write_zeroes() to byte interfaceEric Blake
Rename to bdrv_pwrite_zeroes() to let the compiler ensure we cater to the updated semantics. Do the same for bdrv_co_write_zeroes(). Signed-off-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-06-08block: Add .bdrv_co_pwrite_zeroes()Eric Blake
Update bdrv_co_do_write_zeroes() to be byte-based, and select between the new byte-based bdrv_co_pwrite_zeroes() or the old bdrv_co_write_zeroes(). The next patches will convert drivers, then remove the old interface. Signed-off-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-06-08block: Track write zero limits in bytesEric Blake
Another step towards removing sector-based interfaces: convert the maximum write and minimum alignment values from sectors to bytes. Rename the variables to let the compiler check that all users are converted to the new semantics. The maximum remains an int as long as BDRV_REQUEST_MAX_SECTORS is constrained by INT_MAX (this means that we can't even support a 2G write_zeroes, but just under it) - changing operation lengths to unsigned or to 64-bits is a much bigger audit, and debatable if we even want to do it (since at the core, a 32-bit platform will still have ssize_t as its underlying limit on write()). Meanwhile, alignment is changed to 'uint32_t', since it makes no sense to have an alignment larger than the maximum write, and less painful to use an unsigned type with well-defined behavior in bit operations than to have to worry about what happens if a driver mistakenly supplies a negative alignment. Add an assert that no one was trying to use sectors to get a write zeroes larger than 2G, and therefore that a later conversion to bytes won't be impacted by keeping the limit at 32 bits. Signed-off-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-06-07block: Move BlockRequest type to io.cEric Blake
I was thrown by the fact that the public type BlockRequest had an anonymous union, but no obvious discriminator. Turns out that the only client of the second branch of the union was code internal to io.c, now that commit 91c6e4b killed public multiwrite, so move it into io.c and improve the comments. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1463699150-19445-1-git-send-email-eblake@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
2016-06-07iostatus: fix comments for block_job_iostatus_resetChanglong Xie
Signed-off-by: Changlong Xie <xiecl.fnst@cn.fujitsu.com> Message-id: 1464600491-23340-1-git-send-email-xiecl.fnst@cn.fujitsu.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-06-07block/io: Remove unused bdrv_aio_write_zeroes()Kevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-id: 1464599852-15392-1-git-send-email-kwolf@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-05-25blockjob: Remove BlockJob.bsKevin Wolf
There is a single remaining user in qemu-img, and another one in a test case, both of which can be trivially converted to using BlockJob.blk instead. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2016-05-25backup: Use BlockBackend for I/OKevin Wolf
This changes the backup block job to use the job's BlockBackend for performing its I/O. job->bs isn't used by the backup code any more afterwards. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2016-05-25stream: Use BlockBackend for I/OKevin Wolf
This changes the streaming block job to use the job's BlockBackend for performing the COR reads. job->bs isn't used by the streaming code any more afterwards. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2016-05-25block: Convert block job core to BlockBackendKevin Wolf
This adds a new BlockBackend field to the BlockJob struct, which coexists with the BlockDriverState while converting the individual jobs. When creating a block job, a new BlockBackend is created on top of the given BlockDriverState, and it is destroyed when the BlockJob ends. The reference to the BDS is now held by the BlockBackend instead of calling bdrv_ref/unref manually. We have to be careful when we use bdrv_replace_in_backing_chain() in block jobs because this changes the BDS that job->blk points to. At the moment block jobs are too tightly coupled with their BDS, so that moving a job to another BDS isn't easily possible; therefore, we need to just manually undo this change afterwards. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2016-05-25block: Cancel jobs first in bdrv_close_all()Kevin Wolf
So far, bdrv_close_all() first removed all root BlockDriverStates of BlockBackends and monitor owned BDSes, and then assumed that the remaining BDSes must be related to jobs and cancelled these jobs. This order doesn't work that well any more when block jobs use BlockBackends internally because then they will lose their BDS before being cancelled. This patch changes bdrv_close_all() to first cancel all jobs and then remove all root BDSes from the remaining BBs. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2016-05-25block: keep a list of block jobsAlberto Garcia
The current way to obtain the list of existing block jobs is to iterate over all root nodes and check which ones own a job. Since we want to be able to support block jobs in other nodes as well, this patch keeps a list of jobs that is updated every time one is created or destroyed. Signed-off-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2016-05-25block: Fix reconfiguring graph with drained nodesKevin Wolf
When changing the BlockDriverState that a BdrvChild points to while the node is currently drained, we must call the .drained_end() parent callback. Conversely, when this means attaching a new node that is already drained, we need to call .drained_begin(). bdrv_root_attach_child() takes now an opaque parameter, which is needed because the callbacks must also be called if we're attaching a new child to the BlockBackend when the root node is already drained, and they need a way to identify the BlockBackend. Previously, child->opaque was set too late and the callbacks would still see it as NULL. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com>
2016-05-25block: Make bdrv_open() return a BDSMax Reitz
There are no callers to bdrv_open() or bdrv_open_inherit() left that pass a pointer to a non-NULL BDS pointer as the first argument of these functions, so we can finally drop that parameter and just make them return the new BDS. Generally, the following pattern is applied: bs = NULL; ret = bdrv_open(&bs, ..., &local_err); if (ret < 0) { error_propagate(errp, local_err); ... } by bs = bdrv_open(..., errp); if (!bs) { ret = -EINVAL; ... } Of course, there are only a few instances where the pattern is really pure. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-05-25block: Drop bdrv_new_root()Max Reitz
It is unused now, so we may just as well drop it. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-05-25block: Fix bdrv_next() memory leakKevin Wolf
The bdrv_next() users all leaked the BdrvNextIterator after completing the iteration. Simply changing bdrv_next() to free the iterator before returning NULL at the end of list doesn't work because some callers exit the loop before looking at all BDSes. This patch moves the BdrvNextIterator from the heap to the stack of the caller and switches to a bdrv_first()/bdrv_next() interface for initialising the iterator. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com>
2016-05-19block: Remove BlockDriverState.blkKevin Wolf
This patch removes the remaining users of bs->blk, which will allow us to have multiple BBs on top of a single BDS. In the meantime, all checks that are currently in place to prevent the user from creating such setups can be switched to bdrv_has_blk() instead of accessing BDS.blk. Future patches can allow them and e.g. enable users to mirror to a block device that already has a BlockBackend on it. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2016-05-19block: Avoid bs->blk in bdrv_next()Kevin Wolf
We need to introduce a separate BdrvNextIterator struct that can keep more state than just the current BDS in order to avoid using the bs->blk pointer. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2016-05-19block: Remove bdrv_aio_multiwrite()Kevin Wolf
Since virtio-blk implements request merging itself these days, the only remaining users are test cases for the function. That doesn't make the function exactly useful any more. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>