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2023-06-28block: use bdrv_co_debug_event in coroutine contextPaolo Bonzini
bdrv_co_debug_event was recently introduced, with bdrv_debug_event becoming a wrapper for use in unknown context. Because most of the time bdrv_debug_event is used on a BdrvChild via the wrapper macro BLKDBG_EVENT, introduce a similar macro BLKDBG_CO_EVENT that calls bdrv_co_debug_event, and switch whenever possible. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-ID: <20230601115145.196465-13-pbonzini@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-06-28qed: mark more functions as coroutine_fns and GRAPH_RDLOCKPaolo Bonzini
Mark functions as coroutine_fn when they are only called by other coroutine_fns and they can suspend. Change calls to co_wrappers to use the non-wrapped functions, which in turn requires adding GRAPH_RDLOCK annotations. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-ID: <20230601115145.196465-3-pbonzini@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-05-19block: Call .bdrv_co_create(_opts) unlockedKevin Wolf
These are functions that modify the graph, so they must be able to take a writer lock. This is impossible if they already hold the reader lock. If they need a reader lock for some of their operations, they should take it internally. Many of them go through blk_*(), which will always take the lock itself. Direct calls of bdrv_*() need to take the reader lock. Note that while locking for bdrv_co_*() calls is checked by TSA, this is not the case for the mixed_coroutine_fns bdrv_*(). Holding the lock is still required when they are called from coroutine context like here! This effectively reverts 4ec8df0183, but adds some internal locking instead. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230510203601.418015-2-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-05-10block: .bdrv_open is non-coroutine and unlockedKevin Wolf
Drivers were a bit confused about whether .bdrv_open can run in a coroutine and whether or not it holds a graph lock. It cannot keep a graph lock from the caller across the whole function because it both changes the graph (requires a writer lock) and does I/O (requires a reader lock). Therefore, it should take these locks internally as needed. The functions used to be called in coroutine context during image creation. This was buggy for other reasons, and as of commit 32192301, all block drivers go through no_co_wrappers. So it is not called in coroutine context any more. Fix qcow2 and qed to work with the correct assumptions: The graph lock needs to be taken internally instead of just assuming it's already there, and the coroutine path is dead code that can be removed. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20230504115750.54437-9-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-05-10block: bdrv/blk_co_unref() for calls in coroutine contextKevin Wolf
These functions must not be called in coroutine context, because they need write access to the graph. Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20230504115750.54437-4-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-03-10qed: remove spurious BDRV_POLL_WHILE()Stefan Hajnoczi
This looks like a copy-paste or merge error. BDRV_POLL_WHILE() is already called above. It's not needed in the qemu_in_coroutine() case. Fixes: 9fb4dfc570ce ("qed: make bdrv_qed_do_open a coroutine_fn") Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20230309163134.398707-1-stefanha@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-02-23block: Mark bdrv_co_create() and callers GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_co_create() need to hold a reader lock for the graph. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230203152202.49054-17-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-02-23block: Mark public read/write functions GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_co_pread*/pwrite*() need to hold a reader lock for the graph. For some places, we know that they will hold the lock, but we don't have the GRAPH_RDLOCK annotations yet. In this case, add assume_graph_lock() with a FIXME comment. These places will be removed once everything is properly annotated. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230203152202.49054-12-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-02-23block: Mark read/write in block/io.c GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_driver_*() need to hold a reader lock for the graph. It doesn't add the annotation to public functions yet. For some places, we know that they will hold the lock, but we don't have the GRAPH_RDLOCK annotations yet. In this case, add assume_graph_lock() with a FIXME comment. These places will be removed once everything is properly annotated. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230203152202.49054-11-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-02-23block: Mark bdrv_co_pwrite_zeroes() and callers GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_co_pwrite_zeroes() need to hold a reader lock for the graph. For some places, we know that they will hold the lock, but we don't have the GRAPH_RDLOCK annotations yet. In this case, add assume_graph_lock() with a FIXME comment. These places will be removed once everything is properly annotated. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230203152202.49054-10-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-02-23block: Mark bdrv_co_flush() and callers GRAPH_RDLOCKEmanuele Giuseppe Esposito
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_co_flush() need to hold a reader lock for the graph. For some places, we know that they will hold the lock, but we don't have the GRAPH_RDLOCK annotations yet. In this case, add assume_graph_lock() with a FIXME comment. These places will be removed once everything is properly annotated. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230203152202.49054-8-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-02-23block/qed: add missing graph rdlock in qed_need_check_timer_entryEmanuele Giuseppe Esposito
This function is called in two different places: - timer callback, which does not take the graph rdlock. - bdrv_qed_drain_begin(), which is .bdrv_drain_begin() callback documented as function that does not take the lock. Since it calls recursive functions that traverse the graph, we need to protect them with the graph rdlock. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230203152202.49054-7-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-02-17qed: Fix .bdrv_co_create(_opts) to open images with no_co_wrapperKevin Wolf
.bdrv_co_create implementations run in a coroutine. Therefore they are not allowed to open images directly. Fix the calls to use the corresponding no_co_wrappers instead. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230126172432.436111-8-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Hanna Czenczek <hreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-02-01block: Convert bdrv_get_info() to co_wrapper_mixedEmanuele Giuseppe Esposito
bdrv_get_info() is categorized as an I/O function, and it currently doesn't run in a coroutine. We should let it take a graph rdlock since it traverses the block nodes graph, which however is only possible in a coroutine. Therefore turn it into a co_wrapper to move the actual function into a coroutine where the lock can be taken. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230113204212.359076-11-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-02-01block: use bdrv_co_refresh_total_sectors when possibleEmanuele Giuseppe Esposito
In some places we are sure we are always running in a coroutine, therefore it's useless to call the generated_co_wrapper, instead call directly the _co_ function. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230113204212.359076-9-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-02-01block: Convert bdrv_refresh_total_sectors() to co_wrapper_mixedEmanuele Giuseppe Esposito
BlockDriver->bdrv_getlength is categorized as IO callback, and it currently doesn't run in a coroutine. We should let it take a graph rdlock since the callback traverses the block nodes graph, which however is only possible in a coroutine. Therefore turn it into a co_wrapper to move the actual function into a coroutine where the lock can be taken. Because now this function creates a new coroutine and polls, we need to take the AioContext lock where it is missing, for the only reason that internally co_wrapper calls AIO_WAIT_WHILE and it expects to release the AioContext lock. This is especially messy when a co_wrapper creates a coroutine and polls in bdrv_open_driver, because this function has so many callers in so many context that it can easily lead to deadlocks. Therefore the new rule for bdrv_open_driver is that the caller must always hold the AioContext lock of the given bs (except if it is a coroutine), because the function calls bdrv_refresh_total_sectors() which is now a co_wrapper. Once the rwlock is ultimated and placed in every place it needs to be, we will poll using AIO_WAIT_WHILE_UNLOCKED and remove the AioContext lock. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230113204212.359076-7-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-12-15block: bdrv_create_file is a coroutine_fnEmanuele Giuseppe Esposito
It is always called in coroutine_fn callbacks, therefore it can directly call bdrv_co_create(). Rename it to bdrv_co_create_file too. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20221128142337.657646-9-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-12-15block: Revert .bdrv_drained_begin/end to non-coroutine_fnKevin Wolf
Polling during bdrv_drained_end() can be problematic (and in the future, we may get cases for bdrv_drained_begin() where polling is forbidden, and we don't care about already in-flight requests, but just want to prevent new requests from arriving). The .bdrv_drained_begin/end callbacks running in a coroutine is the only reason why we have to do this polling, so make them non-coroutine callbacks again. None of the callers actually yield any more. This means that bdrv_drained_end() effectively doesn't poll any more, even if AIO_WAIT_WHILE() loops are still there (their condition is false from the beginning). This is generally not a problem, but in test-bdrv-drain, some additional explicit aio_poll() calls need to be added because the test case wants to verify the final state after BHs have executed. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20221118174110.55183-4-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-12-15qed: Don't yield in bdrv_qed_co_drain_begin()Kevin Wolf
We want to change .bdrv_co_drained_begin() back to be a non-coroutine callback, so in preparation, avoid yielding in its implementation. Because we increase bs->in_flight and bdrv_drained_begin() polls, the behaviour is unchanged. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20221118174110.55183-2-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-12-14qapi block: Elide redundant has_FOO in generated CMarkus Armbruster
The has_FOO for pointer-valued FOO are redundant, except for arrays. They are also a nuisance to work with. Recent commit "qapi: Start to elide redundant has_FOO in generated C" provided the means to elide them step by step. This is the step for qapi/block*.json. Said commit explains the transformation in more detail. There is one instance of the invariant violation mentioned there: qcow2_signal_corruption() passes false, "" when node_name is an empty string. Take care to pass NULL then. The previous two commits cleaned up two more. Additionally, helper bdrv_latency_histogram_stats() loses its output parameters and returns a value instead. Cc: Kevin Wolf <kwolf@redhat.com> Cc: Hanna Reitz <hreitz@redhat.com> Cc: qemu-block@nongnu.org Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20221104160712.3005652-11-armbru@redhat.com> [Fixes for #ifndef LIBRBD_SUPPORTS_ENCRYPTION and MacOS squashed in]
2022-10-30Merge tag 'for-upstream' of https://repo.or.cz/qemu/kevin into stagingStefan Hajnoczi
Block layer patches - Cleanup bs->backing and bs->file handling - Refactor bdrv_try_set_aio_context using transactions - Changes for improved coroutine_fn consistency - vhost-user-blk: fix the resize crash - io_uring: Use of io_uring_register_ring_fd() led to breakage, revert - vvfat: Fix some problems with r/w mode - Code cleanup - MAINTAINERS: Fold "Block QAPI, monitor, ..." into "Block layer core" # -----BEGIN PGP SIGNATURE----- # # iQJFBAABCAAvFiEE3D3rFZqa+V09dFb+fwmycsiPL9YFAmNazhIRHGt3b2xmQHJl # ZGhhdC5jb20ACgkQfwmycsiPL9ZyTw/8Dfck/SuxfyeLlnQItkjaV4cnqWOU8vHs # 9x0KhlptCs+HXdF/3iicpA0lHojn7mNnbdFGjPRY4E0LriQv91TQ5ycdEmrseFPf # sgeQlgdKCVU/pHjZ2wYarm2pE43Cx85a5xuufmw+7w49dNNZn14l4t+DgviuClVM # nuVaogfZFbYyetre+Qd2TgLl+gJ+0d4o7Zs5lSWLrT8t0L9AGkcWPA7Nrbl6loIE # dOautV4G7jLjuMiCeJZOGcnuRVe3gCQ5rCGBFzzH4DUtz4BmiYx4hd3LMEsP0PMM # CrsfDZS04Ztybl9M7TmJuwkAm1gx1JDMOuJuh18lbJocIOBvhkKKxY2wI5LIdZVI # ZntmU36RowkX+GGu/PYpYyMjBDClJppZCl7vnjyLYsVt6r0Vu6SmlHpJhcRYabhe # 96Kv1LXH9A6+ogKPU3Layw6JGjg01GNr1ALuT7PO3pGto/JshmOuBEJJDucoF84M # 5AfxFCohMROVldwblA6M0eKnlQBgtr5BvtgbV54BBo88VlFJgDJFQn7R09cTFUEo # UwaJoS+nIaiZ0bQQVZhZloVppUaTdVJojzfVRCZZctga96/tu1HSFnGLnbEFpUN3 # KOf+XnVNS6Ro+nPSDf9bMjbIom2JicGFfV+6yMgIoxY/d5UA2dTZfefil4TAlSod # 6PsTgg+jrm8= # =/Fw0 # -----END PGP SIGNATURE----- # gpg: Signature made Thu 27 Oct 2022 14:29:38 EDT # gpg: using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6 # gpg: issuer "kwolf@redhat.com" # gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full] # Primary key fingerprint: DC3D EB15 9A9A F95D 3D74 56FE 7F09 B272 C88F 2FD6 * tag 'for-upstream' of https://repo.or.cz/qemu/kevin: (58 commits) block/block-backend: blk_set_enable_write_cache is IO_CODE monitor: switch to *_co_* functions vmdk: switch to *_co_* functions vhdx: switch to *_co_* functions vdi: switch to *_co_* functions qed: switch to *_co_* functions qcow2: switch to *_co_* functions qcow: switch to *_co_* functions parallels: switch to *_co_* functions mirror: switch to *_co_* functions block: switch to *_co_* functions commit: switch to *_co_* functions vmdk: manually add more coroutine_fn annotations qcow2: manually add more coroutine_fn annotations qcow: manually add more coroutine_fn annotations blkdebug: add missing coroutine_fn annotation for indirect-called functions qcow2: add coroutine_fn annotation for indirect-called functions block: add missing coroutine_fn annotation to BlockDriverState callbacks coroutine-io: add missing coroutine_fn annotation to prototypes coroutine-lock: add missing coroutine_fn annotation to prototypes ... Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2022-10-27qed: switch to *_co_* functionsAlberto Faria
Signed-off-by: Alberto Faria <afaria@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20221013123711.620631-21-pbonzini@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-10-27block: introduce bdrv_open_file_child() helperVladimir Sementsov-Ogievskiy
Almost all drivers call bdrv_open_child() similarly. Let's create a helper for this. The only not updated drivers that call bdrv_open_child() to set bs->file are raw-format and snapshot-access: raw-format sometimes want to have filtered child but don't set drv->is_filter to true. snapshot-access wants only DATA | PRIMARY Possibly we should implement drv->is_filter_func() handler, to consider raw-format as filter when it works as filter.. But it's another story. Note also, that we decrease assignments to bs->file in code: it helps us restrict modifying this field in further commit. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20220726201134.924743-3-vsementsov@yandex-team.ru> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-10-26block: add BDRV_REQ_REGISTERED_BUF request flagStefan Hajnoczi
Block drivers may optimize I/O requests accessing buffers previously registered with bdrv_register_buf(). Checking whether all elements of a request's QEMUIOVector are within previously registered buffers is expensive, so we need a hint from the user to avoid costly checks. Add a BDRV_REQ_REGISTERED_BUF request flag to indicate that all QEMUIOVector elements in an I/O request are known to be within previously registered buffers. Always pass the flag through to driver read/write functions. There is little harm in passing the flag to a driver that does not use it. Passing the flag to drivers avoids changes across many block drivers. Filter drivers would need to explicitly support the flag and pass through to their children when the children support it. That's a lot of code changes and it's hard to remember to do that everywhere, leading to silent reduced performance when the flag is accidentally dropped. The only problematic scenario with the approach in this patch is when a driver passes the flag through to internal I/O requests that don't use the same I/O buffer. In that case the hint may be set when it should actually be clear. This is a rare case though so the risk is low. Some drivers have assert(!flags), which no longer works when BDRV_REQ_REGISTERED_BUF is passed in. These assertions aren't very useful anyway since the functions are called almost exclusively by bdrv_driver_preadv/pwritev() so if we get flags handling right there then the assertion is not needed. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20221013185908.1297568-7-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2022-10-07qed: add missing coroutine_fn annotationsPaolo Bonzini
Callers of coroutine_fn must be coroutine_fn themselves, or the call must be within "if (qemu_in_coroutine())". Apply coroutine_fn to functions where this holds. Reviewed-by: Alberto Faria <afaria@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20220922084924.201610-18-pbonzini@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-09-30block/qed: Keep auto_backing_file if possibleHanna Reitz
Just like qcow2, qed invokes its open function in its .bdrv_co_invalidate_cache() implementation. Therefore, just like done for qcow2 in HEAD^, update auto_backing_file only if the backing file string in the image header differs from the one we have read before. Signed-off-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20220803144446.20723-3-hreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-07-12block: Change blk_{pread,pwrite}() param orderAlberto Faria
Swap 'buf' and 'bytes' around for consistency with blk_co_{pread,pwrite}(), and in preparation to implement these functions using generated_co_wrapper. Callers were updated using this Coccinelle script: @@ expression blk, offset, buf, bytes, flags; @@ - blk_pread(blk, offset, buf, bytes, flags) + blk_pread(blk, offset, bytes, buf, flags) @@ expression blk, offset, buf, bytes, flags; @@ - blk_pwrite(blk, offset, buf, bytes, flags) + blk_pwrite(blk, offset, bytes, buf, flags) It had no effect on hw/block/nand.c, presumably due to the #if, so that file was updated manually. Overly-long lines were then fixed by hand. Signed-off-by: Alberto Faria <afaria@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20220705161527.1054072-4-afaria@redhat.com> Signed-off-by: Hanna Reitz <hreitz@redhat.com>
2022-07-12block: Make bdrv_{pread,pwrite}() return 0 on successAlberto Faria
They currently return the value of their 'bytes' parameter on success. Make them return 0 instead, for consistency with other I/O functions and in preparation to implement them using generated_co_wrapper. This also makes it clear that short reads/writes are not possible. The few callers that rely on the previous behavior are adjusted accordingly by hand. Signed-off-by: Alberto Faria <afaria@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20220609152744.3891847-4-afaria@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Signed-off-by: Hanna Reitz <hreitz@redhat.com>
2022-07-12block: Change bdrv_{pread,pwrite,pwrite_sync}() param orderAlberto Faria
Swap 'buf' and 'bytes' around for consistency with bdrv_co_{pread,pwrite}(), and in preparation to implement these functions using generated_co_wrapper. Callers were updated using this Coccinelle script: @@ expression child, offset, buf, bytes, flags; @@ - bdrv_pread(child, offset, buf, bytes, flags) + bdrv_pread(child, offset, bytes, buf, flags) @@ expression child, offset, buf, bytes, flags; @@ - bdrv_pwrite(child, offset, buf, bytes, flags) + bdrv_pwrite(child, offset, bytes, buf, flags) @@ expression child, offset, buf, bytes, flags; @@ - bdrv_pwrite_sync(child, offset, buf, bytes, flags) + bdrv_pwrite_sync(child, offset, bytes, buf, flags) Resulting overly-long lines were then fixed by hand. Signed-off-by: Alberto Faria <afaria@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20220609152744.3891847-3-afaria@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Signed-off-by: Hanna Reitz <hreitz@redhat.com>
2022-07-12block: Add a 'flags' param to bdrv_{pread,pwrite,pwrite_sync}()Alberto Faria
For consistency with other I/O functions, and in preparation to implement them using generated_co_wrapper. Callers were updated using this Coccinelle script: @@ expression child, offset, buf, bytes; @@ - bdrv_pread(child, offset, buf, bytes) + bdrv_pread(child, offset, buf, bytes, 0) @@ expression child, offset, buf, bytes; @@ - bdrv_pwrite(child, offset, buf, bytes) + bdrv_pwrite(child, offset, buf, bytes, 0) @@ expression child, offset, buf, bytes; @@ - bdrv_pwrite_sync(child, offset, buf, bytes) + bdrv_pwrite_sync(child, offset, buf, bytes, 0) Resulting overly-long lines were then fixed by hand. Signed-off-by: Alberto Faria <afaria@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20220609152744.3891847-2-afaria@redhat.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Signed-off-by: Hanna Reitz <hreitz@redhat.com>
2022-03-07osdep: Move memalign-related functions to their own headerPeter Maydell
Move the various memalign-related functions out of osdep.h and into their own header, which we include only where they are used. While we're doing this, add some brief documentation comments. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-id: 20220226180723.1706285-10-peter.maydell@linaro.org
2021-09-29block: use int64_t instead of int in driver write_zeroes handlersVladimir Sementsov-Ogievskiy
We are generally moving to int64_t for both offset and bytes parameters on all io paths. Main motivation is realization of 64-bit write_zeroes operation for fast zeroing large disk chunks, up to the whole disk. We chose signed type, to be consistent with off_t (which is signed) and with possibility for signed return type (where negative value means error). So, convert driver write_zeroes handlers bytes parameter to int64_t. The only caller of all updated function is bdrv_co_do_pwrite_zeroes(). bdrv_co_do_pwrite_zeroes() itself is of course OK with widening of callee parameter type. Also, bdrv_co_do_pwrite_zeroes()'s max_write_zeroes is limited to INT_MAX. So, updated functions all are safe, they will not get "bytes" larger than before. Still, let's look through all updated functions, and add assertions to the ones which are actually unprepared to values larger than INT_MAX. For these drivers also set explicit max_pwrite_zeroes limit. Let's go: blkdebug: calculations can't overflow, thanks to bdrv_check_qiov_request() in generic layer. rule_check() and bdrv_co_pwrite_zeroes() both have 64bit argument. blklogwrites: pass to blk_log_writes_co_log() with 64bit argument. blkreplay, copy-on-read, filter-compress: pass to bdrv_co_pwrite_zeroes() which is OK copy-before-write: Calls cbw_do_copy_before_write() and bdrv_co_pwrite_zeroes, both have 64bit argument. file-posix: both handler calls raw_do_pwrite_zeroes, which is updated. In raw_do_pwrite_zeroes() calculations are OK due to bdrv_check_qiov_request(), bytes go to RawPosixAIOData::aio_nbytes which is uint64_t. Check also where that uint64_t gets handed: handle_aiocb_write_zeroes_block() passes a uint64_t[2] to ioctl(BLKZEROOUT), handle_aiocb_write_zeroes() calls do_fallocate() which takes off_t (and we compile to always have 64-bit off_t), as does handle_aiocb_write_zeroes_unmap. All look safe. gluster: bytes go to GlusterAIOCB::size which is int64_t and to glfs_zerofill_async works with off_t. iscsi: Aha, here we deal with iscsi_writesame16_task() that has uint32_t num_blocks argument and iscsi_writesame16_task() has uint16_t argument. Make comments, add assertions and clarify max_pwrite_zeroes calculation. iscsi_allocmap_() functions already has int64_t argument is_byte_request_lun_aligned is simple to update, do it. mirror_top: pass to bdrv_mirror_top_do_write which has uint64_t argument nbd: Aha, here we have protocol limitation, and NBDRequest::len is uint32_t. max_pwrite_zeroes is cleanly set to 32bit value, so we are OK for now. nvme: Again, protocol limitation. And no inherent limit for write-zeroes at all. But from code that calculates cdw12 it's obvious that we do have limit and alignment. Let's clarify it. Also, obviously the code is not prepared to handle bytes=0. Let's handle this case too. trace events already 64bit preallocate: pass to handle_write() and bdrv_co_pwrite_zeroes(), both 64bit. rbd: pass to qemu_rbd_start_co() which is 64bit. qcow2: offset + bytes and alignment still works good (thanks to bdrv_check_qiov_request()), so tail calculation is OK qcow2_subcluster_zeroize() has 64bit argument, should be OK trace events updated qed: qed_co_request wants int nb_sectors. Also in code we have size_t used for request length which may be 32bit. So, let's just keep INT_MAX as a limit (aligning it down to pwrite_zeroes_alignment) and don't care. raw-format: Is OK. raw_adjust_offset and bdrv_co_pwrite_zeroes are both 64bit. throttle: Both throttle_group_co_io_limits_intercept() and bdrv_co_pwrite_zeroes() are 64bit. vmdk: pass to vmdk_pwritev which is 64bit quorum: pass to quorum_co_pwritev() which is 64bit Hooray! At this point all block drivers are prepared to support 64bit write-zero requests, or have explicitly set max_pwrite_zeroes. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210903102807.27127-8-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> [eblake: use <= rather than < in assertions relying on max_pwrite_zeroes] Signed-off-by: Eric Blake <eblake@redhat.com>
2021-03-08block/qed: bdrv_qed_do_open: deal with errpVladimir Sementsov-Ogievskiy
Always set errp on failure. The generic bdrv_open_driver supports driver functions which can return a negative value but forget to set errp. That's a strange thing. Let's improve bdrv_qed_do_open to not behave this way. This allows the simplification of code in bdrv_qed_co_invalidate_cache(). Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <20210202124956.63146-14-vsementsov@virtuozzo.com> [eblake: commit message grammar tweak] Signed-off-by: Eric Blake <eblake@redhat.com>
2020-07-10qapi: Smooth another visitor error checking patternMarkus Armbruster
Convert visit_type_FOO(v, ..., &ptr, &err); ... if (err) { ... } to visit_type_FOO(v, ..., &ptr, errp); ... if (!ptr) { ... } for functions that set @ptr to non-null / null on success / error. Eliminate error_propagate() that are now unnecessary. Delete @err that are now unused. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200707160613.848843-40-armbru@redhat.com>
2020-07-10error: Eliminate error_propagate() with Coccinelle, part 1Markus Armbruster
When all we do with an Error we receive into a local variable is propagating to somewhere else, we can just as well receive it there right away. Convert if (!foo(..., &err)) { ... error_propagate(errp, err); ... return ... } to if (!foo(..., errp)) { ... ... return ... } where nothing else needs @err. Coccinelle script: @rule1 forall@ identifier fun, err, errp, lbl; expression list args, args2; binary operator op; constant c1, c2; symbol false; @@ if ( ( - fun(args, &err, args2) + fun(args, errp, args2) | - !fun(args, &err, args2) + !fun(args, errp, args2) | - fun(args, &err, args2) op c1 + fun(args, errp, args2) op c1 ) ) { ... when != err when != lbl: when strict - error_propagate(errp, err); ... when != err ( return; | return c2; | return false; ) } @rule2 forall@ identifier fun, err, errp, lbl; expression list args, args2; expression var; binary operator op; constant c1, c2; symbol false; @@ - var = fun(args, &err, args2); + var = fun(args, errp, args2); ... when != err if ( ( var | !var | var op c1 ) ) { ... when != err when != lbl: when strict - error_propagate(errp, err); ... when != err ( return; | return c2; | return false; | return var; ) } @depends on rule1 || rule2@ identifier err; @@ - Error *err = NULL; ... when != err Not exactly elegant, I'm afraid. The "when != lbl:" is necessary to avoid transforming if (fun(args, &err)) { goto out } ... out: error_propagate(errp, err); even though other paths to label out still need the error_propagate(). For an actual example, see sclp_realize(). Without the "when strict", Coccinelle transforms vfio_msix_setup(), incorrectly. I don't know what exactly "when strict" does, only that it helps here. The match of return is narrower than what I want, but I can't figure out how to express "return where the operand doesn't use @err". For an example where it's too narrow, see vfio_intx_enable(). Silently fails to convert hw/arm/armsse.c, because Coccinelle gets confused by ARMSSE being used both as typedef and function-like macro there. Converted manually. Line breaks tidied up manually. One nested declaration of @local_err deleted manually. Preexisting unwanted blank line dropped in hw/riscv/sifive_e.c. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200707160613.848843-35-armbru@redhat.com>
2020-07-06qed: Simplify backing readsEric Blake
The other four drivers that support backing files (qcow, qcow2, parallels, vmdk) all rely on the block layer to populate zeroes when reading beyond EOF of a short backing file. We can simplify the qed code by doing likewise. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20200528094405.145708-11-vsementsov@virtuozzo.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-07-06block: drop unallocated_blocks_are_zeroVladimir Sementsov-Ogievskiy
Currently this field only set by qed and qcow2. But in fact, all backing-supporting formats (parallels, qcow, qcow2, qed, vmdk) share these semantics: on unallocated blocks, if there is no backing file they just memset the buffer with zeroes. So, document this behavior for .supports_backing and drop .unallocated_blocks_are_zero Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200528094405.145708-10-vsementsov@virtuozzo.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-05-18block: Use bdrv_default_perms()Max Reitz
bdrv_default_perms() can decide which permission profile to use based on the BdrvChildRole, so block drivers do not need to select it explicitly. The blkverify driver now no longer shares the WRITE permission for the image to verify. We thus have to adjust two places in test-block-iothread not to take it. (Note that in theory, blkverify should behave like quorum in this regard and share neither WRITE nor RESIZE for both of its children. In practice, it does not really matter, because blkverify is used only for debugging, so we might as well keep its permissions rather liberal.) Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200513110544.176672-30-mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Make format drivers use child_of_bdsMax Reitz
Commonly, they need to pass the BDRV_CHILD_IMAGE set as the BdrvChildRole; but there are exceptions for drivers with external data files (qcow2 and vmdk). Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200513110544.176672-26-mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Add BdrvChildRole to BdrvChildMax Reitz
For now, it is always set to 0. Later patches in this series will ensure that all callers pass an appropriate combination of flags. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200513110544.176672-6-mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Add BlockDriver.is_formatMax Reitz
We want to unify child_format and child_file at some point. One of the important things that set format drivers apart from other drivers is that they do not expect other format nodes under them (except in the backing chain), i.e. we must not probe formats inside of formats. That means we need something on which to distinguish format drivers from others, and hence this flag. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-Id: <20200513110544.176672-3-mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-08block: Drop unused .bdrv_has_zero_init_truncateEric Blake
Now that there are no clients of bdrv_has_zero_init_truncate, none of the drivers need to worry about providing it. What's more, this eliminates a source of some confusion: a literal reading of the documentation as written in ceaca56f and implemented in commit 1dcaf527 claims that a driver which returns 0 for bdrv_has_zero_init_truncate() must not return 1 for bdrv_has_zero_init(); this condition was violated for parallels, qcow, and sometimes for vdi, although in practice it did not matter since those drivers also lacked .bdrv_co_truncate. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20200428202905.770727-10-eblake@redhat.com> Acked-by: Richard W.M. Jones <rjones@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-05block: Add blk_new_with_bs() helperEric Blake
There are several callers that need to create a new block backend from an existing BDS; make the task slightly easier with a common helper routine. Suggested-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20200424190903.522087-2-eblake@redhat.com> [mreitz: Set @ret only in error paths, see https://lists.nongnu.org/archive/html/qemu-block/2020-04/msg01216.html] Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200428192648.749066-2-eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-04-30block-backend: Add flags to blk_truncate()Kevin Wolf
Now that node level interface bdrv_truncate() supports passing request flags to the block driver, expose this on the BlockBackend level, too. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200424125448.63318-4-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-04-30block: Add flags to BlockDriver.bdrv_co_truncate()Kevin Wolf
This adds a new BdrvRequestFlags parameter to the .bdrv_co_truncate() driver callbacks, and a supported_truncate_flags field in BlockDriverState that allows drivers to advertise support for request flags in the context of truncate. For now, we always pass 0 and no drivers declare support for any flag. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200424125448.63318-2-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-03-26block: pass BlockDriver reference to the .bdrv_co_createMaxim Levitsky
This will allow the reuse of a single generic .bdrv_co_create implementation for several drivers. No functional changes. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20200326011218.29230-2-mlevitsk@redhat.com> Reviewed-by: Denis V. Lunev <den@openvz.org> Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-10-28block: Pass truncate exact=true where reasonableMax Reitz
This is a change in behavior, so all instances need a good justification. The comments added here should explain my reasoning. qed already had a comment that suggests it always expected bdrv_truncate()/blk_truncate() to behave as if exact=true were passed (c743849bee7 came eight months before 55b949c8476), so it was simply broken until now. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20190918095144.955-8-mreitz@redhat.com Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> [mreitz: Changed comment in qed.c to explain why a new QED file must be empty, as requested and suggested by Maxim] Signed-off-by: Max Reitz <mreitz@redhat.com>
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>
2019-08-19block: Implement .bdrv_has_zero_init_truncate()Max Reitz
We need to implement .bdrv_has_zero_init_truncate() for every block driver that supports truncation and has a .bdrv_has_zero_init() implementation. Implement it the same way each driver implements .bdrv_has_zero_init(). This is at least not any more unsafe than what we had before. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20190724171239.8764-5-mreitz@redhat.com Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-08-16Include qemu/main-loop.h lessMarkus Armbruster
In my "build everything" tree, changing qemu/main-loop.h triggers a recompile of some 5600 out of 6600 objects (not counting tests and objects that don't depend on qemu/osdep.h). It includes block/aio.h, which in turn includes qemu/event_notifier.h, qemu/notify.h, qemu/processor.h, qemu/qsp.h, qemu/queue.h, qemu/thread-posix.h, qemu/thread.h, qemu/timer.h, and a few more. Include qemu/main-loop.h only where it's needed. Touching it now recompiles only some 1700 objects. For block/aio.h and qemu/event_notifier.h, these numbers drop from 5600 to 2800. For the others, they shrink only slightly. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20190812052359.30071-21-armbru@redhat.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>