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* block: move trace probes into bdrv_co_preadv|pwritevDaniel P. Berrange2017-08-071-4/+4
| | | | | | | | | | | | | There are trace probes in bdrv_co_readv|writev, however, the block drivers are being gradually moved over to using the bdrv_co_preadv|pwritev functions instead. As a result some block drivers miss the current probes. Move the probes into bdrv_co_preadv|pwritev instead, so that they are triggered by more (all?) I/O code paths. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-id: 20170804105036.11879-1-berrange@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* Merge remote-tracking branch 'remotes/stefanha/tags/block-pull-request' into ↵Peter Maydell2017-07-181-1/+0Star
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | staging # gpg: Signature made Mon 17 Jul 2017 16:40:18 BST # gpg: using RSA key 0x9CA4ABB381AB73C8 # gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>" # gpg: aka "Stefan Hajnoczi <stefanha@gmail.com>" # Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35 775A 9CA4 ABB3 81AB 73C8 * remotes/stefanha/tags/block-pull-request: block: fix shadowed variable in bdrv_co_pdiscard util/aio-win32: Only select on what we are actually waiting for Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
| * block: fix shadowed variable in bdrv_co_pdiscardDenis V. Lunev2017-07-171-1/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | We've had a shadowed 'ret' variable, which risks returning the wrong value, introduced in commit b9c64947. Signed-off-by: Denis V. Lunev <den@openvz.org> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20170710150559.30163-1-den@openvz.org CC: Stefan Hajnoczi <stefanha@redhat.com> CC: Kevin Wolf <kwolf@redhat.com> CC: Eric Blake <eblake@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* | block: invoke .bdrv_drain callback in coroutine context and from AioContextPaolo Bonzini2017-07-171-9/+33
|/ | | | | | | | | | This will let the callback take a CoMutex in the next patch. Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20170629132749.997-8-pbonzini@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
* block/dirty-bitmap: add readonly field to BdrvDirtyBitmapVladimir Sementsov-Ogievskiy2017-07-111-0/+8
| | | | | | | | | | | It will be needed in following commits for persistent bitmaps. If bitmap is loaded from read-only storage (and we can't mark it "in use" in this storage) corresponding BdrvDirtyBitmap should be read-only. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20170628120530.31251-11-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
* block: Make bdrv_is_allocated_above() byte-basedEric Blake2017-07-101-20/+18Star
| | | | | | | | | | | | | | | | | | | | | | | | | We are gradually moving away from sector-based interfaces, towards byte-based. In the common case, allocation is unlikely to ever use values that are not naturally sector-aligned, but it is possible that byte-based values will let us be more precise about allocation at the end of an unaligned file that can do byte-based access. Changing the signature of the function to use int64_t *pnum ensures that the compiler enforces that all callers are updated. For now, the io.c layer still assert()s that all callers are sector-aligned, but that can be relaxed when a later patch implements byte-based block status. Therefore, for the most part this patch is just the addition of scaling at the callers followed by inverse scaling at bdrv_is_allocated(). But some code, particularly stream_run(), gets a lot simpler because it no longer has to mess with sectors. Leave comments where we can further simplify by switching to byte-based iterations, once later patches eliminate the need for sector-aligned operations. For ease of review, bdrv_is_allocated() was tackled separately. Signed-off-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Minimize raw use of bds->total_sectorsEric Blake2017-07-101-8/+6Star
| | | | | | | | | | | | | | | | | | bdrv_is_allocated_above() was relying on intermediate->total_sectors, which is a field that can have stale contents depending on the value of intermediate->has_variable_length. An audit shows that we are safe (we were first calling through bdrv_co_get_block_status() which in turn calls bdrv_nb_sectors() and therefore just refreshed the current length), but it's nicer to favor our accessor functions to avoid having to repeat such an audit, even if it means refresh_total_sectors() is called more frequently. Suggested-by: John Snow <jsnow@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Manos Pitsidianakis <el13635@mail.ntua.gr> Reviewed-by: Jeff Cody <jcody@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Make bdrv_is_allocated() byte-basedEric Blake2017-07-101-18/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We are gradually moving away from sector-based interfaces, towards byte-based. In the common case, allocation is unlikely to ever use values that are not naturally sector-aligned, but it is possible that byte-based values will let us be more precise about allocation at the end of an unaligned file that can do byte-based access. Changing the signature of the function to use int64_t *pnum ensures that the compiler enforces that all callers are updated. For now, the io.c layer still assert()s that all callers are sector-aligned on input and that *pnum is sector-aligned on return to the caller, but that can be relaxed when a later patch implements byte-based block status. Therefore, this code adds usages like DIV_ROUND_UP(,BDRV_SECTOR_SIZE) to callers that still want aligned values, where the call might reasonbly give non-aligned results in the future; on the other hand, no rounding is needed for callers that should just continue to work with byte alignment. For the most part this patch is just the addition of scaling at the callers followed by inverse scaling at bdrv_is_allocated(). But some code, particularly bdrv_commit(), gets a lot simpler because it no longer has to mess with sectors; also, it is now possible to pass NULL if the caller does not care how much of the image is allocated beyond the initial offset. Leave comments where we can further simplify once a later patch eliminates the need for sector-aligned requests through bdrv_is_allocated(). For ease of review, bdrv_is_allocated_above() will be tackled separately. Signed-off-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Drop unused bdrv_round_sectors_to_clusters()Eric Blake2017-07-101-21/+0Star
| | | | | | | | | | | Now that the last user [mirror_iteration()] has converted to using bytes, we no longer need a function to round sectors to clusters. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Guarantee that *file is set on bdrv_get_block_status()Eric Blake2017-07-101-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | We document that *file is valid if the return is not an error and includes BDRV_BLOCK_OFFSET_VALID, but forgot to obey this contract when a driver (such as blkdebug) lacks a callback. Messed up in commit 67a0fd2 (v2.6), when we added the file parameter. Enhance qemu-iotest 177 to cover this, using a sequence that would print garbage or even SEGV, because it was dererefencing through uninitialized memory. [The resulting test output shows that we have less-than-ideal block status from the blkdebug driver, but that's a separate fix coming up soon.] Setting *file on all paths that return BDRV_BLOCK_OFFSET_VALID is enough to fix the crash, but we can go one step further: always setting *file, even on error, means that a broken caller that blindly dereferences file without checking for error is now more likely to get a reliable SEGV instead of randomly acting on garbage, making it easier to diagnose such buggy callers. Adding an assertion that file is set where expected doesn't hurt either. CC: qemu-stable@nongnu.org Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Exploit BDRV_BLOCK_EOF for larger zero blocksEric Blake2017-06-301-5/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | When we have a BDS with unallocated clusters, but asking the status of its underlying bs->file or backing layer encounters an end-of-file condition, we know that the rest of the unallocated area will read as zeroes. However, pre-patch, this required two separate calls to bdrv_get_block_status(), as the first call stops at the point where the underlying file ends. Thanks to BDRV_BLOCK_EOF, we can now widen the results of the primary status if the secondary status already includes BDRV_BLOCK_ZERO. In turn, this fixes a TODO mentioned in iotest 154, where we can now see that all sectors in a partial cluster at the end of a file read as zero when coupling the shorter backing file's status along with our knowledge that the remaining sectors came from an unallocated cluster. Also, note that the loop in bdrv_co_get_block_status_above() had an inefficent exit: in cases where the active layer sets BDRV_BLOCK_ZERO but does NOT set BDRV_BLOCK_ALLOCATED (namely, where we know we read zeroes merely because our unallocated clusters lie beyond the backing file's shorter length), we still ended up probing the backing layer even though we already had a good answer. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20170505021500.19315-3-eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
* block: Add BDRV_BLOCK_EOF to bdrv_get_block_status()Eric Blake2017-06-301-4/+11
| | | | | | | | | | | | | | | | Just as the block layer already sets BDRV_BLOCK_ALLOCATED as a shortcut for subsequent operations, there are also some optimizations that are made easier if we can quickly tell that *pnum will advance us to the end of a file, via a new BDRV_BLOCK_EOF which gets set by the block layer. This just plumbs up the new bit; subsequent patches will make use of it. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20170505021500.19315-2-eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
* block: change variable names in BlockDriverStateManos Pitsidianakis2017-06-261-24/+24
| | | | | | | | | | | Change the 'int count' parameter in *pwrite_zeros, *pdiscard related functions (and some others) to 'int bytes', as they both refer to bytes. This helps with code legibility. Signed-off-by: Manos Pitsidianakis <el13635@mail.ntua.gr> Message-id: 20170609101808.13506-1-el13635@mail.ntua.gr Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
* block: Remove bdrv_aio_readv/writev/flush()Kevin Wolf2017-06-261-171/+0Star
| | | | | | | These functions are unused now. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: use BDRV_POLL_WHILE() in bdrv_rw_vmstate()Stefan Hajnoczi2017-06-261-3/+1Star
| | | | | | | | | | | | | | | | | | Calling aio_poll() directly may have been fine previously, but this is the future, man! The difference between an aio_poll() loop and BDRV_POLL_WHILE() is that BDRV_POLL_WHILE() releases the AioContext around aio_poll(). This allows the IOThread to run fd handlers or BHs to complete the request. Failure to release the AioContext causes deadlocks. Using BDRV_POLL_WHILE() partially fixes a 'savevm' hang with -object iothread. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: count bdrv_co_rw_vmstate() requestsStefan Hajnoczi2017-06-261-5/+12
| | | | | | | | | | | | | | | | Call bdrv_inc/dec_in_flight() for vmstate reads/writes. This seems unnecessary at first glance because vmstate reads/writes are done synchronously while the guest is stopped. But we need the bdrv_wakeup() in bdrv_dec_in_flight() so the main loop sees request completion. Besides, it's cleaner to count vmstate reads/writes like ordinary read/write requests. The bdrv_wakeup() partially fixes a 'savevm' hang with -object iothread. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: protect tracked_requests and flush_queue with reqs_lockPaolo Bonzini2017-06-161-2/+14
| | | | | | | Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20170605123908.18777-14-pbonzini@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
* block: access write_gen with atomicsPaolo Bonzini2017-06-161-3/+3
| | | | | | | Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20170605123908.18777-13-pbonzini@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
* block: use Stat64 for wr_highest_offsetPaolo Bonzini2017-06-161-3/+1Star
| | | | | | | Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20170605123908.18777-12-pbonzini@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
* block: access io_plugged with atomic opsPaolo Bonzini2017-06-161-2/+2
| | | | | | | Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20170605123908.18777-7-pbonzini@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
* block: access wakeup with atomic opsPaolo Bonzini2017-06-161-1/+2
| | | | | | | Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20170605123908.18777-6-pbonzini@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
* block: access serialising_in_flight with atomic opsPaolo Bonzini2017-06-161-3/+3
| | | | | | | Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20170605123908.18777-5-pbonzini@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
* block: access quiesce_counter with atomic opsPaolo Bonzini2017-06-161-2/+2
| | | | | | | | Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20170605123908.18777-3-pbonzini@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
* block: access copy_on_read with atomic opsPaolo Bonzini2017-06-161-4/+4
| | | | | | | Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20170605123908.18777-2-pbonzini@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
* blockjob: introduce block_job_pause/resume_allPaolo Bonzini2017-05-241-16/+3Star
| | | | | | | | | | | | | Remove use of block_job_pause/resume from outside blockjob.c, thus making them static. The new functions are used by the block layer, so place them in blockjob_int.h. Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com> Message-id: 20170508141310.8674-5-pbonzini@redhat.com Signed-off-by: Jeff Cody <jcody@redhat.com>
* block: Simplify BDRV_BLOCK_RAW recursionEric Blake2017-05-121-2/+2
| | | | | | | | | | | | | | | | | | Since we are already in coroutine context during the body of bdrv_co_get_block_status(), we can shave off a few layers of wrappers when recursing to query the protocol when a format driver returned BDRV_BLOCK_RAW. Note that we are already using the correct recursion later on in the same function, when probing whether the protocol layer is sparse in order to find out if we can add BDRV_BLOCK_ZERO to an existing BDRV_BLOCK_DATA|BDRV_BLOCK_OFFSET_VALID. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 20170504173745.27414-1-eblake@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: fix alignment calculations in bdrv_co_do_zero_pwritevDenis V. Lunev2017-04-271-1/+1
| | | | | | | | | | | | | | | | | | | tail_padding_bytes is calculated wrong. F.e. for offset = 0 bytes = 2048 align = 512 we will have tail_padding_bytes = 512 which is definitely wrong. The patch fixes that arithmetics. Fortunately this problem is harmless, we will have 1 extra allocation and free thus there is no need to put this into stable. The problem is here from the very beginning. Signed-off-by: Denis V. Lunev <den@openvz.org> CC: Stefan Hajnoczi <stefanha@redhat.com> CC: Fam Zheng <famz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Remove NULL check in bdrv_co_flushFam Zheng2017-04-271-1/+1
| | | | | | | | | | Reported by Coverity. We already use bs in bdrv_inc_in_flight before checking for NULL. It is unnecessary as all callers pass non-NULL bs, so drop it. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* Revert "block/io: Comment out permission assertions"Max Reitz2017-04-271-10/+2Star
| | | | | | | | | | | This reverts commit e3e0003a8f6570aba1421ef99a0b383a43371a74. This commit was necessary for the 2.9 release because we were unable to fix the underlying issue(s) in time. However, we will be for 2.10. Signed-off-by: Max Reitz <mreitz@redhat.com> Acked-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Walk bs->children carefully in bdrv_drain_recurseFam Zheng2017-04-181-3/+20
| | | | | | | | | | | | | | | | | | | | The recursive bdrv_drain_recurse may run a block job completion BH that drops nodes. The coming changes will make that more likely and use-after-free would happen without this patch Stash the bs pointer and use bdrv_ref/bdrv_unref in addition to QLIST_FOREACH_SAFE to prevent such a case from happening. Since bdrv_unref accesses global state that is not protected by the AioContext lock, we cannot use bdrv_ref/bdrv_unref unconditionally. Fortunately the protection is not needed in IOThread because only main loop can modify a graph with the AioContext lock held. Signed-off-by: Fam Zheng <famz@redhat.com> Message-Id: <20170418143044.12187-2-famz@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com> Tested-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
* block/io: Comment out permission assertionsMax Reitz2017-04-111-2/+10
| | | | | | | | | | | | | | | In case of block migration, there may be writes to BlockBackends that do not have the write permission taken. Before this issue is fixed (which is not going to happen in 2.9), we therefore cannot assert that this is the case. Suggested-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Tested-by: Kevin Wolf <kwolf@redhat.com> Message-id: 20170411145050.31290-1-mreitz@redhat.com Tested-by: Laurent Vivier <lvivier@redhat.com> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
* block: Fix bdrv_co_flush early returnFam Zheng2017-04-111-5/+7
| | | | | | | | | | | | bdrv_inc_in_flight and bdrv_dec_in_flight are mandatory for BDRV_POLL_WHILE to work, even for the shortcut case where flush is unnecessary. Move the if block to below bdrv_dec_in_flight, and BTW fix the variable declaration position. Signed-off-by: Fam Zheng <famz@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
* block: Use bdrv_coroutine_enter to start I/O coroutinesFam Zheng2017-04-111-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BDRV_POLL_WHILE waits for the started I/O by releasing bs's ctx then polling the main context, which relies on the yielded coroutine continuing on bs->ctx before notifying qemu_aio_context with bdrv_wakeup(). Thus, using qemu_coroutine_enter to start I/O is wrong because if the coroutine is entered from main loop, co->ctx will be qemu_aio_context, as a result of the "release, poll, acquire" loop of BDRV_POLL_WHILE, race conditions happen when both main thread and the iothread access the same BDS: main loop iothread ----------------------------------------------------------------------- blockdev_snapshot aio_context_acquire(bs->ctx) virtio_scsi_data_plane_handle_cmd bdrv_drained_begin(bs->ctx) bdrv_flush(bs) bdrv_co_flush(bs) aio_context_acquire(bs->ctx).enter ... qemu_coroutine_yield(co) BDRV_POLL_WHILE() aio_context_release(bs->ctx) aio_context_acquire(bs->ctx).return ... aio_co_wake(co) aio_poll(qemu_aio_context) ... co_schedule_bh_cb() ... qemu_coroutine_enter(co) ... /* (A) bdrv_co_flush(bs) /* (B) I/O on bs */ continues... */ aio_context_release(bs->ctx) aio_context_acquire(bs->ctx) Note that in above case, bdrv_drained_begin() doesn't do the "release, poll, acquire" in BDRV_POLL_WHILE, because bs->in_flight == 0. Fix this by using bdrv_coroutine_enter and enter coroutine in the right context. iotests 109 output is updated because the coroutine reenter flow during mirror job complete is different (now through co_queue_wakeup, instead of the unconditional qemu_coroutine_switch before), making the end job len different. Signed-off-by: Fam Zheng <famz@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com>
* block: Make bdrv_parent_drained_begin/end publicFam Zheng2017-04-111-2/+2
| | | | | | | Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com>
* block: Don't check permissions for copy on readKevin Wolf2017-04-071-1/+8
| | | | | | | | | | | The assertion is currently failing. We can't require callers to have write permissions when all they are doing is a read, so comment it out. Add a FIXME comment in the code so that the check is re-enabled when copy on read is refactored into its own filter driver. Reported-by: Richard W.M. Jones <rjones@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Richard W.M. Jones <rjones@redhat.com>
* block: Request block status from *file for BDRV_BLOCK_RAWKevin Wolf2017-03-131-1/+1
| | | | | | | | This fixes bdrv_co_get_block_status() for the bdrv_mirror_top block driver, which must fall through to bs->backing instead of bs->file. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
* block: Assertions for resize permissionKevin Wolf2017-02-281-0/+1
| | | | | | | | | This adds an assertion that ensures that the necessary resize permission has been granted before bdrv_truncate() is called. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Fam Zheng <famz@redhat.com>
* block: Assertions for write permissionsKevin Wolf2017-02-281-0/+3
| | | | | | | | | This adds assertions that ensure that the necessary write permissions have been granted before someone attempts to write to a node. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Acked-by: Fam Zheng <famz@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
* block: Pass BdrvChild to bdrv_aligned_preadv/pwritev and copy-on-readKevin Wolf2017-02-281-16/+21
| | | | | | | | | This is where we want to check the permissions, so we need to have the BdrvChild around where they are stored. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Acked-by: Fam Zheng <famz@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
* coroutine-lock: add mutex argument to CoQueue APIsPaolo Bonzini2017-02-211-2/+2
| | | | | | | | | | All that CoQueue needs in order to become thread-safe is help from an external mutex. Add this to the API. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 20170213181244.16297-6-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: explicitly acquire aiocontext in aio callbacks that need itPaolo Bonzini2017-02-211-5/+1Star
| | | | | | | | | Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Message-id: 20170213135235.12274-16-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: explicitly acquire aiocontext in bottom halves that need itPaolo Bonzini2017-02-211-1/+5
| | | | | | | | | Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Message-id: 20170213135235.12274-15-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: explicitly acquire aiocontext in timers that need itPaolo Bonzini2017-02-211-0/+5
| | | | | | | | | Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Message-id: 20170213135235.12274-13-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: move AioContext, QEMUTimer, main-loop to libqemuutilPaolo Bonzini2017-02-211-29/+0Star
| | | | | | | | | | | | | | | | | | AioContext is fairly self contained, the only dependency is QEMUTimer but that in turn doesn't need anything else. So move them out of block-obj-y to avoid introducing a dependency from io/ to block-obj-y. main-loop and its dependency iohandler also need to be moved, because later in this series io/ will call iohandler_get_aio_context. [Changed copyright "the QEMU team" to "other QEMU contributors" as suggested by Daniel Berrange and agreed by Paolo. --Stefan] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 20170213135235.12274-2-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: get rid of bdrv_io_unplugged_begin/endPaolo Bonzini2017-01-161-39/+2Star
| | | | | | | | | | | | | | | bdrv_io_plug and bdrv_io_unplug are only called (via their BlockBackend equivalents) after starting asynchronous I/O. bdrv_drain is not going to be called while they are running, because---even if a coroutine runs for some reason---it will only drain in the next iteration of the event loop through bdrv_co_yield_to_drain. So this mechanism is unnecessary, get rid of it. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 20161129113334.605-1-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: Pass unaligned discard requests to driversEric Blake2016-11-221-13/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Discard is advisory, so rounding the requests to alignment boundaries is never semantically wrong from the data that the guest sees. But at least the Dell Equallogic iSCSI SANs has an interesting property that its advertised discard alignment is 15M, yet documents that discarding a sequence of 1M slices will eventually result in the 15M page being marked as discarded, and it is possible to observe which pages have been discarded. Between commits 9f1963b and b8d0a980, we converted the block layer to a byte-based interface that ultimately ignores any unaligned head or tail based on the driver's advertised discard granularity, which means that qemu 2.7 refuses to pass any discard request smaller than 15M down to the Dell Equallogic hardware. This is a slight regression in behavior compared to earlier qemu, where a guest executing discards in power-of-2 chunks used to be able to get every page discarded, but is now left with various pages still allocated because the guest requests did not align with the hardware's 15M pages. Since the SCSI specification says nothing about a minimum discard granularity, and only documents the preferred alignment, it is best if the block layer gives the driver every bit of information about discard requests, rather than rounding it to alignment boundaries early. Rework the block layer discard algorithm to mirror the write zero algorithm: always peel off any unaligned head or tail and manage that in isolation, then do the bulk of the request on an aligned boundary. The fallback when the driver returns -ENOTSUP for an unaligned request is to silently ignore that portion of the discard request; but for devices that can pass the partial request all the way down to hardware, this can result in the hardware coalescing requests and discarding aligned pages after all. Reported by: Peter Lieven <pl@kamp.de> CC: qemu-stable@nongnu.org Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Let write zeroes fallback work even with small max_transferEric Blake2016-11-221-5/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 443668ca rewrote the write_zeroes logic to guarantee that an unaligned request never crosses a cluster boundary. But in the rewrite, the new code assumed that at most one iteration would be needed to get to an alignment boundary. However, it is easy to trigger an assertion failure: the Linux kernel limits loopback devices to advertise a max_transfer of only 64k. Any operation that requires falling back to writes rather than more efficient zeroing must obey max_transfer during that fallback, which means an unaligned head may require multiple iterations of the write fallbacks before reaching the aligned boundaries, when layering a format with clusters larger than 64k atop the protocol of file access to a loopback device. Test case: $ qemu-img create -f qcow2 -o cluster_size=1M file 10M $ losetup /dev/loop2 /path/to/file $ qemu-io -f qcow2 /dev/loop2 qemu-io> w 7m 1k qemu-io> w -z 8003584 2093056 In fairness to Denis (as the original listed author of the culprit commit), the faulty logic for at most one iteration is probably all my fault in reworking his idea. But the solution is to restore what was in place prior to that commit: when dealing with an unaligned head or tail, iterate as many times as necessary while fragmenting the operation at max_transfer boundaries. Reported-by: Ed Swierk <eswierk@skyportsystems.com> CC: qemu-stable@nongnu.org CC: Denis V. Lunev <den@openvz.org> Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: Don't mark node clean after failed flushKevin Wolf2016-11-081-1/+3
| | | | | | | | | | | | | | | | | | | | | Commit 3ff2f67a changed bdrv_co_flush() so that no flush is issues if the image hasn't been dirtied since the last flush. This is not quite correct: The condition should be that the image hasn't been dirtied since the last _successful_ flush. This patch changes the logic accordingly. Without this fix, subsequent bdrv_co_flush() calls would return success without actually doing anything even though the image is still dirty. The difference is visible in some blkdebug test cases where error messages incorrectly disappeared after commit 3ff2f67a. Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Denis V. Lunev <den@openvz.org> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 1478300595-10090-1-git-send-email-kwolf@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: Add bdrv_drain_all_{begin,end}()Alberto Garcia2016-10-311-3/+24
| | | | | | | | | | | | | | | | | | | | | bdrv_drain_all() doesn't allow the caller to do anything after all pending requests have been completed but before block jobs are resumed. This patch splits bdrv_drain_all() into _begin() and _end() for that purpose. It also adds aio_{disable,enable}_external() calls to disable external clients in the meantime. An important restriction of this split is that no new block jobs or BlockDriverStates can be created between the bdrv_drain_all_begin() and bdrv_drain_all_end() calls. This is not a concern now because we'll only be using this in bdrv_reopen_multiple(), but it must be dealt with if we ever have other uses cases in the future. Signed-off-by: Alberto Garcia <berto@igalia.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block: only call aio_poll on the current thread's AioContextPaolo Bonzini2016-10-281-0/+12
| | | | | | | | | | | | | | | | | | 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: Fam Zheng <famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <1477565348-5458-18-git-send-email-pbonzini@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
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