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4db7ba3b87
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>
108 lines
3.5 KiB
C
108 lines
3.5 KiB
C
/*
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* Block layer code related to image creation
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*
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* Copyright (c) 2018 Kevin Wolf <kwolf@redhat.com>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu/osdep.h"
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#include "block/block_int.h"
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#include "qemu/job.h"
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#include "qemu/main-loop.h"
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#include "qapi/qapi-commands-block-core.h"
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#include "qapi/qapi-visit-block-core.h"
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#include "qapi/clone-visitor.h"
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#include "qapi/error.h"
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typedef struct BlockdevCreateJob {
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Job common;
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BlockDriver *drv;
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BlockdevCreateOptions *opts;
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} BlockdevCreateJob;
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static int coroutine_fn blockdev_create_run(Job *job, Error **errp)
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{
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BlockdevCreateJob *s = container_of(job, BlockdevCreateJob, common);
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int ret;
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GLOBAL_STATE_CODE();
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job_progress_set_remaining(&s->common, 1);
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ret = s->drv->bdrv_co_create(s->opts, errp);
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job_progress_update(&s->common, 1);
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qapi_free_BlockdevCreateOptions(s->opts);
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return ret;
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}
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static const JobDriver blockdev_create_job_driver = {
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.instance_size = sizeof(BlockdevCreateJob),
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.job_type = JOB_TYPE_CREATE,
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.run = blockdev_create_run,
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};
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/* Checking whether the function is present doesn't require the graph lock */
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static inline bool TSA_NO_TSA has_bdrv_co_create(BlockDriver *drv)
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{
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return drv->bdrv_co_create;
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}
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void qmp_blockdev_create(const char *job_id, BlockdevCreateOptions *options,
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Error **errp)
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{
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BlockdevCreateJob *s;
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const char *fmt = BlockdevDriver_str(options->driver);
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BlockDriver *drv = bdrv_find_format(fmt);
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if (!drv) {
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error_setg(errp, "Block driver '%s' not found or not supported", fmt);
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return;
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}
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/* If the driver is in the schema, we know that it exists. But it may not
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* be whitelisted. */
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if (bdrv_uses_whitelist() && !bdrv_is_whitelisted(drv, false)) {
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error_setg(errp, "Driver is not whitelisted");
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return;
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}
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/* Error out if the driver doesn't support .bdrv_co_create */
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if (!has_bdrv_co_create(drv)) {
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error_setg(errp, "Driver does not support blockdev-create");
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return;
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}
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/* Create the block job */
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/* TODO Running in the main context. Block drivers need to error out or add
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* locking when they use a BDS in a different AioContext. */
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s = job_create(job_id, &blockdev_create_job_driver, NULL,
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qemu_get_aio_context(), JOB_DEFAULT | JOB_MANUAL_DISMISS,
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NULL, NULL, errp);
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if (!s) {
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return;
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}
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s->drv = drv,
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s->opts = QAPI_CLONE(BlockdevCreateOptions, options),
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job_start(&s->common);
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}
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