The functionality offered by blk_pread_unthrottled() goes back to commit498e386c58
. Then, we couldn't perform I/O throttling with synchronous requests because timers wouldn't be executed in polling loops. So the commit automatically disabled I/O throttling as soon as a synchronous request was issued. However, for geometry detection during disk initialisation, we always used (and still use) synchronous requests even if guest requests use AIO later. Geometry detection was not wanted to disable I/O throttling, so bdrv_pread_unthrottled() was introduced which disabled throttling only temporarily. All of this isn't necessary any more because we do run timers in polling loop and even synchronous requests are now using coroutine infrastructure internally. For this reason, commit90c78624f
already removed the automatic disabling of I/O throttling. It's time to get rid of the workaround for the removed code, and its abuse of blk_root_drained_begin()/end(), as well. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
264 lines
12 KiB
C
264 lines
12 KiB
C
/*
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* QEMU Block backends
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*
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* Copyright (C) 2014-2016 Red Hat, Inc.
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*
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* Authors:
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* Markus Armbruster <armbru@redhat.com>,
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*
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* This work is licensed under the terms of the GNU LGPL, version 2.1
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* or later. See the COPYING.LIB file in the top-level directory.
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*/
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#ifndef BLOCK_BACKEND_H
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#define BLOCK_BACKEND_H
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#include "qemu/iov.h"
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#include "block/throttle-groups.h"
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/*
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* TODO Have to include block/block.h for a bunch of block layer
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* types. Unfortunately, this pulls in the whole BlockDriverState
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* API, which we don't want used by many BlockBackend users. Some of
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* the types belong here, and the rest should be split into a common
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* header and one for the BlockDriverState API.
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*/
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#include "block/block.h"
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/* Callbacks for block device models */
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typedef struct BlockDevOps {
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/*
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* Runs when virtual media changed (monitor commands eject, change)
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* Argument load is true on load and false on eject.
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* Beware: doesn't run when a host device's physical media
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* changes. Sure would be useful if it did.
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* Device models with removable media must implement this callback.
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*/
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void (*change_media_cb)(void *opaque, bool load, Error **errp);
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/*
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* Runs when an eject request is issued from the monitor, the tray
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* is closed, and the medium is locked.
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* Device models that do not implement is_medium_locked will not need
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* this callback. Device models that can lock the medium or tray might
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* want to implement the callback and unlock the tray when "force" is
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* true, even if they do not support eject requests.
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*/
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void (*eject_request_cb)(void *opaque, bool force);
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/*
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* Is the virtual tray open?
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* Device models implement this only when the device has a tray.
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*/
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bool (*is_tray_open)(void *opaque);
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/*
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* Is the virtual medium locked into the device?
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* Device models implement this only when device has such a lock.
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*/
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bool (*is_medium_locked)(void *opaque);
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/*
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* Runs when the size changed (e.g. monitor command block_resize)
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*/
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void (*resize_cb)(void *opaque);
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/*
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* Runs when the backend receives a drain request.
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*/
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void (*drained_begin)(void *opaque);
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/*
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* Runs when the backend's last drain request ends.
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*/
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void (*drained_end)(void *opaque);
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} BlockDevOps;
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/* This struct is embedded in (the private) BlockBackend struct and contains
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* fields that must be public. This is in particular for QLIST_ENTRY() and
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* friends so that BlockBackends can be kept in lists outside block-backend.c
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* */
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typedef struct BlockBackendPublic {
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ThrottleGroupMember throttle_group_member;
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} BlockBackendPublic;
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BlockBackend *blk_new(AioContext *ctx, uint64_t perm, uint64_t shared_perm);
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BlockBackend *blk_new_open(const char *filename, const char *reference,
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QDict *options, int flags, Error **errp);
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int blk_get_refcnt(BlockBackend *blk);
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void blk_ref(BlockBackend *blk);
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void blk_unref(BlockBackend *blk);
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void blk_remove_all_bs(void);
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const char *blk_name(const BlockBackend *blk);
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BlockBackend *blk_by_name(const char *name);
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BlockBackend *blk_next(BlockBackend *blk);
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BlockBackend *blk_all_next(BlockBackend *blk);
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bool monitor_add_blk(BlockBackend *blk, const char *name, Error **errp);
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void monitor_remove_blk(BlockBackend *blk);
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BlockBackendPublic *blk_get_public(BlockBackend *blk);
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BlockBackend *blk_by_public(BlockBackendPublic *public);
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BlockDriverState *blk_bs(BlockBackend *blk);
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void blk_remove_bs(BlockBackend *blk);
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int blk_insert_bs(BlockBackend *blk, BlockDriverState *bs, Error **errp);
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bool bdrv_has_blk(BlockDriverState *bs);
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bool bdrv_is_root_node(BlockDriverState *bs);
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int blk_set_perm(BlockBackend *blk, uint64_t perm, uint64_t shared_perm,
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Error **errp);
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void blk_get_perm(BlockBackend *blk, uint64_t *perm, uint64_t *shared_perm);
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void blk_set_allow_write_beyond_eof(BlockBackend *blk, bool allow);
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void blk_set_allow_aio_context_change(BlockBackend *blk, bool allow);
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void blk_iostatus_enable(BlockBackend *blk);
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bool blk_iostatus_is_enabled(const BlockBackend *blk);
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BlockDeviceIoStatus blk_iostatus(const BlockBackend *blk);
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void blk_iostatus_disable(BlockBackend *blk);
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void blk_iostatus_reset(BlockBackend *blk);
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void blk_iostatus_set_err(BlockBackend *blk, int error);
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int blk_attach_dev(BlockBackend *blk, DeviceState *dev);
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void blk_detach_dev(BlockBackend *blk, DeviceState *dev);
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DeviceState *blk_get_attached_dev(BlockBackend *blk);
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char *blk_get_attached_dev_id(BlockBackend *blk);
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BlockBackend *blk_by_dev(void *dev);
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BlockBackend *blk_by_qdev_id(const char *id, Error **errp);
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void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops, void *opaque);
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int coroutine_fn blk_co_preadv(BlockBackend *blk, int64_t offset,
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unsigned int bytes, QEMUIOVector *qiov,
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BdrvRequestFlags flags);
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int coroutine_fn blk_co_pwritev(BlockBackend *blk, int64_t offset,
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unsigned int bytes, QEMUIOVector *qiov,
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BdrvRequestFlags flags);
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static inline int coroutine_fn blk_co_pread(BlockBackend *blk, int64_t offset,
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unsigned int bytes, void *buf,
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BdrvRequestFlags flags)
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{
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QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
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return blk_co_preadv(blk, offset, bytes, &qiov, flags);
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}
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static inline int coroutine_fn blk_co_pwrite(BlockBackend *blk, int64_t offset,
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unsigned int bytes, void *buf,
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BdrvRequestFlags flags)
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{
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QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
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return blk_co_pwritev(blk, offset, bytes, &qiov, flags);
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}
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int blk_pwrite_zeroes(BlockBackend *blk, int64_t offset,
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int bytes, BdrvRequestFlags flags);
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BlockAIOCB *blk_aio_pwrite_zeroes(BlockBackend *blk, int64_t offset,
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int bytes, BdrvRequestFlags flags,
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BlockCompletionFunc *cb, void *opaque);
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int blk_make_zero(BlockBackend *blk, BdrvRequestFlags flags);
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int blk_pread(BlockBackend *blk, int64_t offset, void *buf, int bytes);
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int blk_pwrite(BlockBackend *blk, int64_t offset, const void *buf, int bytes,
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BdrvRequestFlags flags);
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int64_t blk_getlength(BlockBackend *blk);
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void blk_get_geometry(BlockBackend *blk, uint64_t *nb_sectors_ptr);
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int64_t blk_nb_sectors(BlockBackend *blk);
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BlockAIOCB *blk_aio_preadv(BlockBackend *blk, int64_t offset,
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QEMUIOVector *qiov, BdrvRequestFlags flags,
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BlockCompletionFunc *cb, void *opaque);
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BlockAIOCB *blk_aio_pwritev(BlockBackend *blk, int64_t offset,
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QEMUIOVector *qiov, BdrvRequestFlags flags,
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BlockCompletionFunc *cb, void *opaque);
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BlockAIOCB *blk_aio_flush(BlockBackend *blk,
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BlockCompletionFunc *cb, void *opaque);
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BlockAIOCB *blk_aio_pdiscard(BlockBackend *blk, int64_t offset, int bytes,
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BlockCompletionFunc *cb, void *opaque);
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void blk_aio_cancel(BlockAIOCB *acb);
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void blk_aio_cancel_async(BlockAIOCB *acb);
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int blk_co_ioctl(BlockBackend *blk, unsigned long int req, void *buf);
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int blk_ioctl(BlockBackend *blk, unsigned long int req, void *buf);
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BlockAIOCB *blk_aio_ioctl(BlockBackend *blk, unsigned long int req, void *buf,
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BlockCompletionFunc *cb, void *opaque);
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int blk_co_pdiscard(BlockBackend *blk, int64_t offset, int bytes);
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int blk_co_flush(BlockBackend *blk);
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int blk_flush(BlockBackend *blk);
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int blk_commit_all(void);
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void blk_inc_in_flight(BlockBackend *blk);
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void blk_dec_in_flight(BlockBackend *blk);
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void blk_drain(BlockBackend *blk);
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void blk_drain_all(void);
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void blk_set_on_error(BlockBackend *blk, BlockdevOnError on_read_error,
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BlockdevOnError on_write_error);
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BlockdevOnError blk_get_on_error(BlockBackend *blk, bool is_read);
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BlockErrorAction blk_get_error_action(BlockBackend *blk, bool is_read,
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int error);
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void blk_error_action(BlockBackend *blk, BlockErrorAction action,
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bool is_read, int error);
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bool blk_is_read_only(BlockBackend *blk);
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bool blk_is_sg(BlockBackend *blk);
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bool blk_enable_write_cache(BlockBackend *blk);
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void blk_set_enable_write_cache(BlockBackend *blk, bool wce);
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void blk_invalidate_cache(BlockBackend *blk, Error **errp);
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bool blk_is_inserted(BlockBackend *blk);
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bool blk_is_available(BlockBackend *blk);
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void blk_lock_medium(BlockBackend *blk, bool locked);
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void blk_eject(BlockBackend *blk, bool eject_flag);
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int blk_get_flags(BlockBackend *blk);
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uint32_t blk_get_request_alignment(BlockBackend *blk);
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uint32_t blk_get_max_transfer(BlockBackend *blk);
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int blk_get_max_iov(BlockBackend *blk);
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void blk_set_guest_block_size(BlockBackend *blk, int align);
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void *blk_try_blockalign(BlockBackend *blk, size_t size);
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void *blk_blockalign(BlockBackend *blk, size_t size);
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bool blk_op_is_blocked(BlockBackend *blk, BlockOpType op, Error **errp);
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void blk_op_unblock(BlockBackend *blk, BlockOpType op, Error *reason);
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void blk_op_block_all(BlockBackend *blk, Error *reason);
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void blk_op_unblock_all(BlockBackend *blk, Error *reason);
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AioContext *blk_get_aio_context(BlockBackend *blk);
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int blk_set_aio_context(BlockBackend *blk, AioContext *new_context,
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Error **errp);
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void blk_add_aio_context_notifier(BlockBackend *blk,
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void (*attached_aio_context)(AioContext *new_context, void *opaque),
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void (*detach_aio_context)(void *opaque), void *opaque);
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void blk_remove_aio_context_notifier(BlockBackend *blk,
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void (*attached_aio_context)(AioContext *,
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void *),
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void (*detach_aio_context)(void *),
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void *opaque);
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void blk_add_remove_bs_notifier(BlockBackend *blk, Notifier *notify);
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void blk_add_insert_bs_notifier(BlockBackend *blk, Notifier *notify);
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void blk_io_plug(BlockBackend *blk);
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void blk_io_unplug(BlockBackend *blk);
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BlockAcctStats *blk_get_stats(BlockBackend *blk);
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BlockBackendRootState *blk_get_root_state(BlockBackend *blk);
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void blk_update_root_state(BlockBackend *blk);
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bool blk_get_detect_zeroes_from_root_state(BlockBackend *blk);
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int blk_get_open_flags_from_root_state(BlockBackend *blk);
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void *blk_aio_get(const AIOCBInfo *aiocb_info, BlockBackend *blk,
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BlockCompletionFunc *cb, void *opaque);
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int coroutine_fn blk_co_pwrite_zeroes(BlockBackend *blk, int64_t offset,
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int bytes, BdrvRequestFlags flags);
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int blk_pwrite_compressed(BlockBackend *blk, int64_t offset, const void *buf,
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int bytes);
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int blk_truncate(BlockBackend *blk, int64_t offset, PreallocMode prealloc,
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Error **errp);
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int blk_pdiscard(BlockBackend *blk, int64_t offset, int bytes);
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int blk_save_vmstate(BlockBackend *blk, const uint8_t *buf,
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int64_t pos, int size);
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int blk_load_vmstate(BlockBackend *blk, uint8_t *buf, int64_t pos, int size);
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int blk_probe_blocksizes(BlockBackend *blk, BlockSizes *bsz);
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int blk_probe_geometry(BlockBackend *blk, HDGeometry *geo);
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BlockAIOCB *blk_abort_aio_request(BlockBackend *blk,
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BlockCompletionFunc *cb,
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void *opaque, int ret);
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void blk_set_io_limits(BlockBackend *blk, ThrottleConfig *cfg);
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void blk_io_limits_disable(BlockBackend *blk);
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void blk_io_limits_enable(BlockBackend *blk, const char *group);
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void blk_io_limits_update_group(BlockBackend *blk, const char *group);
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void blk_set_force_allow_inactivate(BlockBackend *blk);
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void blk_register_buf(BlockBackend *blk, void *host, size_t size);
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void blk_unregister_buf(BlockBackend *blk, void *host);
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int coroutine_fn blk_co_copy_range(BlockBackend *blk_in, int64_t off_in,
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BlockBackend *blk_out, int64_t off_out,
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int bytes, BdrvRequestFlags read_flags,
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BdrvRequestFlags write_flags);
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const BdrvChild *blk_root(BlockBackend *blk);
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#endif
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