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2019-10-28block: Add @exact parameter to bdrv_co_truncate()Max Reitz
We have two drivers (iscsi and file-posix) that (in some cases) return success from their .bdrv_co_truncate() implementation if the block device is larger than the requested offset, but cannot be shrunk. Some callers do not want that behavior, so this patch adds a new parameter that they can use to turn off that behavior. This patch just adds the parameter and lets the block/io.c and block/block-backend.c functions pass it around. All other callers always pass false and none of the implementations evaluate it, so that this patch does not change existing behavior. Future patches take care of that. Suggested-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20190918095144.955-5-mreitz@redhat.com Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-10-28mirror: Do not dereference invalid pointersMax Reitz
mirror_exit_common() may be called twice (if it is called from mirror_prepare() and fails, it will be called from mirror_abort() again). In such a case, many of the pointers in the MirrorBlockJob object will already be freed. This can be seen most reliably for s->target, which is set to NULL (and then dereferenced by blk_bs()). Cc: qemu-stable@nongnu.org Fixes: 737efc1eda23b904fbe0e66b37715fb0e5c3e58b Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20191014153931.20699-2-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-10-28Revert "mirror: Only mirror granularity-aligned chunks"Vladimir Sementsov-Ogievskiy
This reverts commit 9adc1cb49af8d4e54f57980b1eed5c0a4b2dafa6. "mirror: Only mirror granularity-aligned chunks" Since previous commit unaligned chunks are supported by do_sync_target_write. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20191011090711.19940-6-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-10-28block/mirror: support unaligned write in active mirrorVladimir Sementsov-Ogievskiy
Prior 9adc1cb49af8d do_sync_target_write had a bug: it reset aligned-up region in the dirty bitmap, which means that we may not copy some bytes and assume them copied, which actually leads to producing corrupted target. So 9adc1cb49af8d forced dirty bitmap granularity to be request_alignment for mirror-top filter, so we are not working with unaligned requests. However forcing large alignment obviously decreases performance of unaligned requests. This commit provides another solution for the problem: if unaligned padding is already dirty, we can safely ignore it, as 1. It's dirty, it will be copied by mirror_iteration anyway 2. It's dirty, so skipping it now we don't increase dirtiness of the bitmap and therefore don't damage "synchronicity" of the write-blocking mirror. If unaligned padding is not dirty, we just write it, no reason to touch dirty bitmap if we succeed (on failure we'll set the whole region ofcourse, but we loss "synchronicity" on failure anyway). Note: we need to disable dirty_bitmap, otherwise we will not be able to see in do_sync_target_write bitmap state before current operation. We may of course check dirty bitmap before the operation in bdrv_mirror_top_do_write and remember it, but we don't need active dirty bitmap for write-blocking mirror anyway. New code-path is unused until the following commit reverts 9adc1cb49af8d. Suggested-by: Denis V. Lunev <den@openvz.org> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20191011090711.19940-5-vsementsov@virtuozzo.com Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-10-28block/mirror: simplify do_sync_target_writeVladimir Sementsov-Ogievskiy
do_sync_target_write is called from bdrv_mirror_top_do_write after write/discard operation, all inside active_write/active_write_settle protecting us from mirror iteration. So the whole area is dirty for sure, no reason to examine dirty bitmap. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20191011090711.19940-3-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-10-17block/dirty-bitmap: add bs linkVladimir Sementsov-Ogievskiy
Add bs field to BdrvDirtyBitmap structure. Drop BlockDriverState parameter from bitmap APIs where possible. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 20190916141911.5255-3-vsementsov@virtuozzo.com [Rebased on top of block-copy. --js] Signed-off-by: John Snow <jsnow@redhat.com>
2019-09-10job: drop job_drainVladimir Sementsov-Ogievskiy
In job_finish_sync job_enter should be enough for a job to make some progress and draining is a wrong tool for it. So use job_enter directly here and drop job_drain with all related staff not used more. Suggested-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Tested-by: John Snow <jsnow@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2019-08-19mirror: Fix bdrv_has_zero_init() useMax Reitz
bdrv_has_zero_init() only has meaning for newly created images or image areas. If the mirror job itself did not create the image, it cannot rely on bdrv_has_zero_init()'s result to carry any meaning. This is the case for drive-mirror with mode=existing and always for blockdev-mirror. Note that we only have to zero-initialize the target with sync=full, because other modes actually do not promise that the target will contain the same data as the source after the job -- sync=top only promises to copy anything allocated in the top layer, and sync=none will only copy new I/O. (Which is how mirror has always handled it.) Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20190724171239.8764-3-mreitz@redhat.com Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-08-16block/dirty-bitmap: add bdrv_dirty_bitmap_getJohn Snow
Add a public interface for get. While we're at it, rename "bdrv_get_dirty_bitmap_locked" to "bdrv_dirty_bitmap_get_locked". (There are more functions to rename to the bdrv_dirty_bitmap_VERB form, but they will wait until the conclusion of this series.) Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20190709232550.10724-11-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2019-08-16block/backup: Add mirror sync mode 'bitmap'John Snow
We don't need or want a new sync mode for simple differences in semantics. Create a new mode simply named "BITMAP" that is designed to make use of the new Bitmap Sync Mode field. Because the only bitmap sync mode is 'on-success', this adds no new functionality to the backup job (yet). The old incremental backup mode is maintained as a syntactic sugar for sync=bitmap, mode=on-success. Add all of the plumbing necessary to support this new instruction. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20190709232550.10724-6-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
2019-08-16block-backend: Queue requests while drainedKevin Wolf
This fixes devices like IDE that can still start new requests from I/O handlers in the CPU thread while the block backend is drained. The basic assumption is that in a drain section, no new requests should be allowed through a BlockBackend (blk_drained_begin/end don't exist, we get drain sections only on the node level). However, there are two special cases where requests should not be queued: 1. Block jobs: We already make sure that block jobs are paused in a drain section, so they won't start new requests. However, if the drain_begin is called on the job's BlockBackend first, it can happen that we deadlock because the job stays busy until it reaches a pause point - which it can't if its requests aren't processed any more. The proper solution here would be to make all requests through the job's filter node instead of using a BlockBackend. For now, just disabling request queuing on the job BlockBackend is simpler. 2. In test cases where making requests through bdrv_* would be cumbersome because we'd need a BdrvChild. As we already got the functionality to disable request queuing from 1., use it in tests, too, for convenience. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2019-08-16mirror: Keep mirror_top_bs drained after dropping permissionsKevin Wolf
mirror_top_bs is currently implicitly drained through its connection to the source or the target node. However, the drain section for target_bs ends early after moving mirror_top_bs from src to target_bs, so that requests can already be restarted while mirror_top_bs is still present in the chain, but has dropped all permissions and therefore runs into an assertion failure like this: qemu-system-x86_64: block/io.c:1634: bdrv_co_write_req_prepare: Assertion `child->perm & BLK_PERM_WRITE' failed. Keep mirror_top_bs drained until all graph changes have completed. Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2019-08-06mirror: Only mirror granularity-aligned chunksMax Reitz
In write-blocking mode, all writes to the top node directly go to the target. We must only mirror chunks of data that are aligned to the job's granularity, because that is how the dirty bitmap works. Therefore, the request alignment for writes must be the job's granularity (in write-blocking mode). Unfortunately, this forces all reads and writes to have the same granularity (we only need this alignment for writes to the target, not the source), but that is something to be fixed another time. Cc: qemu-stable@nongnu.org Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20190805153308.2657-1-mreitz@redhat.com Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Fixes: d06107ade0ce74dc39739bac80de84b51ec18546 Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-07-15block: Add BDS.never_freezeMax Reitz
The commit and the mirror block job must be able to drop their filter node at any point. However, this will not be possible if any of the BdrvChild links to them is frozen. Therefore, we need to prevent them from ever becoming frozen. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 20190703172813.6868-2-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-07-02block: include base when checking image chain for block allocationAndrey Shinkevich
This patch is used in the 'block/stream: introduce a bottom node' that is following. Instead of the base node, the caller may pass the node that has the base as its backing image to the function bdrv_is_allocated_above() with a new parameter include_base = true and get rid of the dependency on the base that may change during commit/stream parallel jobs. Now, if the specified base is not found in the backing image chain, the QEMU will abort. Suggested-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 1559152576-281803-2-git-send-email-andrey.shinkevich@virtuozzo.com [mreitz: Squashed in the following as a rebase on conflicting patches:] Message-id: e3cf99ae-62e9-8b6e-5a06-d3c8b9363b85@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-06-18block/mirror: Fix child permissionsMax Reitz
We cannot use bdrv_child_try_set_perm() to give up all restrictions on the child edge, and still have bdrv_mirror_top_child_perm() request BLK_PERM_WRITE. Fix this by making bdrv_mirror_top_child_perm() return 0/BLK_PERM_ALL when we want to give up all permissions, and replacing bdrv_child_try_set_perm() by bdrv_child_refresh_perms(). The bdrv_child_try_set_perm() before removing the node with bdrv_replace_node() is then unnecessary. No permissions have changed since the previous invocation of bdrv_child_try_set_perm(). Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2019-06-18block/replication: drop usage of bs->jobVladimir Sementsov-Ogievskiy
We are going to remove bs->job pointer. Drop it's usage in replication code. Additionally we have to return job pointer from some mirror APIs. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2019-06-04block: Remove wrong bdrv_set_aio_context() callsKevin Wolf
The mirror and commit block jobs use bdrv_set_aio_context() to move their filter node into the right AioContext before hooking it up in the graph. Similarly, bdrv_open_backing_file() explicitly moves the backing file node into the right AioContext first. This isn't necessary any more, they get automatically moved into the right context now when attaching them. However, in the case of bdrv_open_backing_file() with a node reference, it's actually not only unnecessary, but even wrong: The unchecked bdrv_set_aio_context() changes the AioContext of the child node even if other parents require it to retain the old context. So this is not only a simplification, but a bug fix, too. Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1684342 Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2019-06-04block: Add BlockBackend.ctxKevin Wolf
This adds a new parameter to blk_new() which requires its callers to declare from which AioContext this BlockBackend is going to be used (or the locks of which AioContext need to be taken anyway). The given context is only stored and kept up to date when changing AioContexts. Actually applying the stored AioContext to the root node is saved for another commit. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2019-05-20blockjob: Propagate AioContext change to all job nodesKevin Wolf
Block jobs require that all of the nodes the job is using are in the same AioContext. Therefore all BdrvChild objects of the job propagate .(can_)set_aio_context to all other job nodes, so that the switch is checked and performed consistently even if both nodes are in different subtrees. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2019-03-26block: Advertise BDRV_REQ_NO_FALLBACK in filter driversKevin Wolf
Filter drivers that support .bdrv_co_pwrite_zeroes can safely advertise BDRV_REQ_NO_FALLBACK because they just forward the request flags to their child node. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Acked-by: Eric Blake <eblake@redhat.com>
2019-03-19mirror: Confirm we're quiesced only if the job is paused or cancelledSergio Lopez
While child_job_drained_begin() calls to job_pause(), the job doesn't actually transition between states until it runs again and reaches a pause point. This means bdrv_drained_begin() may return with some jobs using the node still having 'busy == true'. As a consequence, block_job_detach_aio_context() may get into a deadlock, waiting for the job to be actually paused, while the coroutine servicing the job is yielding and doesn't get the opportunity to get scheduled again. This situation can be reproduced by issuing a 'block-commit' immediately followed by a 'device_del'. To ensure bdrv_drained_begin() only returns when the jobs have been paused, we change mirror_drained_poll() to only confirm it's quiesced when job->paused == true and there aren't any in-flight requests, except if we reached that point by a drained section initiated by the mirror/commit job itself. The other block jobs shouldn't need any changes, as the default drained_poll() behavior is to only confirm it's quiesced if the job is not busy or completed. Signed-off-by: Sergio Lopez <slp@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2019-03-12block: Freeze the backing chain for the duration of the mirror jobAlberto Garcia
Signed-off-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2019-02-25block: Purify .bdrv_refresh_filename()Max Reitz
Currently, BlockDriver.bdrv_refresh_filename() is supposed to both refresh the filename (BDS.exact_filename) and set BDS.full_open_options. Now that we have generic code in the central bdrv_refresh_filename() for creating BDS.full_open_options, we can drop the latter part from all BlockDriver.bdrv_refresh_filename() implementations. This also means that we can drop all of the existing default code for this from the global bdrv_refresh_filename() itself. Furthermore, we now have to call BlockDriver.bdrv_refresh_filename() after having set BDS.full_open_options, because the block driver's implementation should now be allowed to depend on BDS.full_open_options being set correctly. Finally, with this patch we can drop the @options parameter from BlockDriver.bdrv_refresh_filename(); also, add a comment on this function's purpose in block/block_int.h while touching its interface. This completely obsoletes blklogwrite's implementation of .bdrv_refresh_filename(). Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20190201192935.18394-25-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-02-25block: Use children list in bdrv_refresh_filenameMax Reitz
bdrv_refresh_filename() should invoke itself recursively on all children, not just on file. With that change, we can remove the manual invocations in blkverify, quorum, commit, mirror, and blklogwrites. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 20190201192935.18394-3-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-02-01mirror: Block the source BlockDriverState in mirror_start_job()Alberto Garcia
The mirror_start_job() function used for the commit-active job blocks the source, target and all intermediate nodes for the duration of the job. target <- intermediate <- source Since 4ef85a9c2339 this function creates a dummy mirror_top_bs that goes on top of the source node, and it is this dummy node that gets blocked instead. The source node is never blocked or added to the job's list of nodes. target <- intermediate <- source <- mirror_top At the moment I don't think it is possible to exploit this problem because any additional job on 'source' would either be forbidden for other reasons or it would need to involve an additional node that is blocked, causing an error. This can be seen in the error messages, however, because they never refer to the source node being blocked: $ qemu-img create -f qcow2 hd0.qcow2 1M $ qemu-img create -f qcow2 -b hd0.qcow2 hd1.qcow2 $ qemu-io -c 'write 0 1M' hd0.qcow2 $ $QEMU -drive if=none,file=hd1.qcow2,node-name=hd1 { "execute": "qmp_capabilities" } { "execute": "block-commit", "arguments": {"device": "hd1", "speed": 256}} { "execute": "block-stream", "arguments": {"device": "hd1"}} { "error": {"class": "GenericError", "desc": "Node 'hd0' is busy: block device is in use by block job: commit"}} After this patch the error message refers to 'hd1', as it should. The expected output of iotest 141 also needs to be updated for the same reason. Signed-off-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2019-02-01mirror: Release the dirty bitmap if mirror_start_job() failsAlberto Garcia
At the moment I don't see how to make this function fail after the dirty bitmap has been created, but if that was possible then we would hit the assert(QLIST_EMPTY(&bs->dirty_bitmaps)) in bdrv_close(). Signed-off-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2019-01-15block/mirror: fix and improve do_sync_target_writeVladimir Sementsov-Ogievskiy
Use bdrv_dirty_bitmap_next_dirty_area() instead of bdrv_dirty_iter_next_area(), because of the following problems of bdrv_dirty_iter_next_area(): 1. Using HBitmap iterators we should carefully handle unaligned offset, as first call to hbitmap_iter_next() may return a value less than original offset (actually, it will be original offset rounded down to bitmap granularity). This handling is not done in do_sync_target_write(). 2. bdrv_dirty_iter_next_area() handles unaligned max_offset incorrectly: look at the code: if (max_offset == iter->bitmap->size) { /* If max_offset points to the image end, round it up by the * bitmap granularity */ gran_max_offset = ROUND_UP(max_offset, granularity); } else { gran_max_offset = max_offset; } ret = hbitmap_iter_next(&iter->hbi, false); if (ret < 0 || ret + granularity > gran_max_offset) { return false; } and assume that max_offset != iter->bitmap->size but still unaligned. if 0 < ret < max_offset we found dirty area, but the function can return false in this case (if ret + granularity > max_offset). 3. bdrv_dirty_iter_next_area() uses inefficient loop to find the end of the dirty area. Let's use more efficient hbitmap_next_zero instead (bdrv_dirty_bitmap_next_dirty_area() do so) Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2019-01-11qemu/queue.h: leave head structs anonymous unless necessaryPaolo Bonzini
Most list head structs need not be given a name. In most cases the name is given just in case one is going to use QTAILQ_LAST, QTAILQ_PREV or reverse iteration, but this does not apply to lists of other kinds, and even for QTAILQ in practice this is only rarely needed. In addition, we will soon reimplement those macros completely so that they do not need a name for the head struct. So clean up everything, not giving a name except in the rare case where it is necessary. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-12-14block/mirror: add missing coroutine_fn annotationsStefan Hajnoczi
Marking a function coroutine_fn currently has no effect on the compiler, but it documents that this function must be called from coroutine context and it may yield. This is important information for the programmer. Also, if we ever transition to a stackless coroutine implementation, then it's likely that the annotation will become mandatory so the compiler can use the correct calling convention for coroutine functions. Cc: Max Reitz <mreitz@redhat.com> Cc: John Snow <jsnow@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-12-14block: Use bdrv_reopen_set_read_only() in the mirror driverAlberto Garcia
The 'block-commit' QMP command is implemented internally using two different drivers. If the source image is the active layer then the mirror driver is used (commit_active_start()), otherwise the commit driver is used (commit_start()). In both cases the destination image must be put temporarily in read-write mode. This is done correctly in the latter case, but what commit_active_start() does is copy all flags instead. This patch replaces the bdrv_reopen() calls in that function with bdrv_reopen_set_read_only() so that only the read-only status is changed. A similar change is made in mirror_exit(), which is also used by the 'drive-mirror' and 'blockdev-mirror' commands. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-12-03mirror: fix dead-lockVladimir Sementsov-Ogievskiy
Let start from the beginning: Commit b9e413dd375 (in 2.9) "block: explicitly acquire aiocontext in aio callbacks that need it" added pairs of aio_context_acquire/release to mirror_write_complete and mirror_read_complete, when they were aio callbacks for blk_aio_* calls. Then, commit 2e1990b26e5 (in 3.0) "block/mirror: Convert to coroutines" dropped these blk_aio_* calls, than mirror_write_complete and mirror_read_complete are not callbacks more, and don't need additional aiocontext acquiring. Furthermore, mirror_read_complete calls blk_co_pwritev inside these pair of aio_context_acquire/release, which leads to the following dead-lock with mirror: (gdb) info thr Id Target Id Frame 3 Thread (LWP 145412) "qemu-system-x86" syscall () 2 Thread (LWP 145416) "qemu-system-x86" __lll_lock_wait () * 1 Thread (LWP 145411) "qemu-system-x86" __lll_lock_wait () (gdb) bt #0 __lll_lock_wait () #1 _L_lock_812 () #2 __GI___pthread_mutex_lock #3 qemu_mutex_lock_impl (mutex=0x561032dce420 <qemu_global_mutex>, file=0x5610327d8654 "util/main-loop.c", line=236) at util/qemu-thread-posix.c:66 #4 qemu_mutex_lock_iothread_impl #5 os_host_main_loop_wait (timeout=480116000) at util/main-loop.c:236 #6 main_loop_wait (nonblocking=0) at util/main-loop.c:497 #7 main_loop () at vl.c:1892 #8 main Printing contents of qemu_global_mutex, I see that "__owner = 145416", so, thr1 is main loop, and now it wants BQL, which is owned by thr2. (gdb) thr 2 (gdb) bt #0 __lll_lock_wait () #1 _L_lock_870 () #2 __GI___pthread_mutex_lock #3 qemu_mutex_lock_impl (mutex=0x561034d25dc0, ... #4 aio_context_acquire (ctx=0x561034d25d60) #5 dma_blk_cb #6 dma_blk_io #7 dma_blk_read #8 ide_dma_cb #9 bmdma_cmd_writeb #10 bmdma_write #11 memory_region_write_accessor #12 access_with_adjusted_size #15 flatview_write #16 address_space_write #17 address_space_rw #18 kvm_handle_io #19 kvm_cpu_exec #20 qemu_kvm_cpu_thread_fn #21 qemu_thread_start #22 start_thread #23 clone () Printing mutex in fr 2, I see "__owner = 145411", so thr2 wants aio context mutex, which is owned by thr1. Classic dead-lock. Then, let's check that aio context is hold by mirror coroutine: just print coroutine stack of first tracked request in mirror job target: (gdb) [...] (gdb) qemu coroutine 0x561035dd0860 #0 qemu_coroutine_switch #1 qemu_coroutine_yield #2 qemu_co_mutex_lock_slowpath #3 qemu_co_mutex_lock #4 qcow2_co_pwritev #5 bdrv_driver_pwritev #6 bdrv_aligned_pwritev #7 bdrv_co_pwritev #8 blk_co_pwritev #9 mirror_read_complete () at block/mirror.c:232 #10 mirror_co_read () at block/mirror.c:370 #11 coroutine_trampoline #12 __start_context Yes it is mirror_read_complete calling blk_co_pwritev after acquiring aio context. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-09-25block/mirror: conservative mirror_exit refactorJohn Snow
For purposes of minimum code movement, refactor the mirror_exit callback to use the post-finalization callbacks in a trivial way. Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 20180906130225.5118-7-jsnow@redhat.com Reviewed-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> [mreitz: Added comment for the mirror_exit() function] Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-09-25block/mirror: don't install backing chain on abortJohn Snow
In cases where we abort the block/mirror job, there's no point in installing the new backing chain before we finish aborting. Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 20180906130225.5118-6-jsnow@redhat.com Reviewed-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-09-25block/mirror: add block job creation flagsJohn Snow
Add support for taking and passing forward job creation flags. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com> Message-id: 20180906130225.5118-3-jsnow@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-08-31block/mirror: utilize job_exit shimJohn Snow
Change the manual deferment to mirror_exit into the implicit callback to job_exit and the mirror_exit callback. This does change the order of some bdrv_unref calls and job_completed, but thanks to the new context in which we call .exit, this is safe to defer the possible flushing of any nodes to the job_finalize_single cleanup stage. Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 20180830015734.19765-6-jsnow@redhat.com Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-08-31jobs: canonize Error objectJohn Snow
Jobs presently use both an Error object in the case of the create job, and char strings in the case of generic errors elsewhere. Unify the two paths as just j->err, and remove the extra argument from job_completed. The integer error code for job_completed is kept for now, to be removed shortly in a separate patch. Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 20180830015734.19765-3-jsnow@redhat.com [mreitz: Dropped a superfluous g_strdup()] Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-08-31jobs: change start callback to run callbackJohn Snow
Presently we codify the entry point for a job as the "start" callback, but a more apt name would be "run" to clarify the idea that when this function returns we consider the job to have "finished," except for any cleanup which occurs in separate callbacks later. As part of this clarification, change the signature to include an error object and a return code. The error ptr is not yet used, and the return code while captured, will be overwritten by actions in the job_completed function. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20180830015734.19765-2-jsnow@redhat.com Reviewed-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-08-15block: drop empty .bdrv_close handlersVladimir Sementsov-Ogievskiy
.bdrv_close handler is optional after previous commit, no needs to keep empty functions more. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-08-15mirror: Fail gracefully for source == targetKevin Wolf
blockdev-mirror with the same node for source and target segfaults today: A node is in its own backing chain, so mirror_start_job() decides that this is an active commit. When adding the intermediate nodes with block_job_add_bdrv(), it starts the iteration through the subchain with the backing file of source, though, so it never reaches target and instead runs into NULL at the base. While we could fix that by starting with source itself, there is no point in allowing mirroring a node into itself and I wouldn't be surprised if this caused more problems later. So just check for this scenario and error out. Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2018-07-10block: Use BdrvChild to discardFam Zheng
Other I/O functions are already using a BdrvChild pointer in the API, so make discard do the same. It makes it possible to initiate the same permission checks before doing I/O, and much easier to share the helper functions for this, which will be added and used by write, truncate and copy range paths. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-06-18block/mirror: Add copy mode QAPI interfaceMax Reitz
This patch allows the user to specify whether to use active or only background mode for mirror block jobs. Currently, this setting will remain constant for the duration of the entire block job. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 20180613181823.13618-14-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-06-18block/mirror: Add active mirroringMax Reitz
This patch implements active synchronous mirroring. In active mode, the passive mechanism will still be in place and is used to copy all initially dirty clusters off the source disk; but every write request will write data both to the source and the target disk, so the source cannot be dirtied faster than data is mirrored to the target. Also, once the block job has converged (BLOCK_JOB_READY sent), source and target are guaranteed to stay in sync (unless an error occurs). Active mode is completely optional and currently disabled at runtime. A later patch will add a way for users to enable it. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 20180613181823.13618-13-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-06-18block/mirror: Add MirrorBDSOpaqueMax Reitz
This will allow us to access the block job data when the mirror block driver becomes more complex. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 20180613181823.13618-11-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-06-18block/mirror: Use source as a BdrvChildMax Reitz
With this, the mirror_top_bs is no longer just a technically required node in the BDS graph but actually represents the block job operation. Also, drop MirrorBlockJob.source, as we can reach it through mirror_top_bs->backing. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 20180613181823.13618-6-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-06-18block/mirror: Wait for in-flight op conflictsMax Reitz
This patch makes the mirror code differentiate between simply waiting for any operation to complete (mirror_wait_for_free_in_flight_slot()) and specifically waiting for all operations touching a certain range of the virtual disk to complete (mirror_wait_on_conflicts()). Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 20180613181823.13618-5-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-06-18block/mirror: Use CoQueue to wait on in-flight opsMax Reitz
Attach a CoQueue to each in-flight operation so if we need to wait for any we can use it to wait instead of just blindly yielding and hoping for some operation to wake us. A later patch will use this infrastructure to allow requests accessing the same area of the virtual disk to specifically wait for each other. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 20180613181823.13618-4-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-06-18block/mirror: Convert to coroutinesMax Reitz
In order to talk to the source BDS (and maybe in the future to the target BDS as well) directly, we need to convert our existing AIO requests into coroutine I/O requests. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 20180613181823.13618-3-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-06-18block/mirror: Pull out mirror_perform()Max Reitz
When converting mirror's I/O to coroutines, we are going to need a point where these coroutines are created. mirror_perform() is going to be that point. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 20180613181823.13618-2-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-06-18block: Really pause block jobs on drainKevin Wolf
We already requested that block jobs be paused in .bdrv_drained_begin, but no guarantee was made that the job was actually inactive at the point where bdrv_drained_begin() returned. This introduces a new callback BdrvChildRole.bdrv_drained_poll() and uses it to make bdrv_drain_poll() consider block jobs using the node to be drained. For the test case to work as expected, we have to switch from block_job_sleep_ns() to qemu_co_sleep_ns() so that the test job is even considered active and must be waited for when draining the node. Signed-off-by: Kevin Wolf <kwolf@redhat.com>