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block: Convert bdrv_refresh_total_sectors() to co_wrapper_mixed
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>
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c057960c4e
commit
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35 changed files with 161 additions and 121 deletions
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@ -1002,7 +1002,7 @@ fail:
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return ret;
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}
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static int64_t nvme_getlength(BlockDriverState *bs)
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static int64_t coroutine_fn nvme_co_getlength(BlockDriverState *bs)
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{
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BDRVNVMeState *s = bs->opaque;
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return s->nsze << s->blkshift;
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@ -1486,7 +1486,7 @@ static int coroutine_fn nvme_co_truncate(BlockDriverState *bs, int64_t offset,
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return -ENOTSUP;
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}
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cur_length = nvme_getlength(bs);
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cur_length = nvme_co_getlength(bs);
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if (offset != cur_length && exact) {
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error_setg(errp, "Cannot resize NVMe devices");
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return -ENOTSUP;
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@ -1643,7 +1643,7 @@ static BlockDriver bdrv_nvme = {
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.bdrv_parse_filename = nvme_parse_filename,
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.bdrv_file_open = nvme_file_open,
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.bdrv_close = nvme_close,
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.bdrv_getlength = nvme_getlength,
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.bdrv_co_getlength = nvme_co_getlength,
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.bdrv_probe_blocksizes = nvme_probe_blocksizes,
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.bdrv_co_truncate = nvme_co_truncate,
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