include/block/block-io.h - qemu - Git at Google

 /*
  * QEMU System Emulator block driver
  *
  * Copyright (c) 2003 Fabrice Bellard
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
 #ifndef BLOCK_IO_H
 #define BLOCK_IO_H

 #include "block-common.h"

 /*
  * I/O API functions. These functions are thread-safe, and therefore
  * can run in any thread as long as the thread has called
  * aio_context_acquire/release().
  *
  * These functions can only call functions from I/O and Common categories,
  * but can be invoked by GS, "I/O or GS" and I/O APIs.
  *
  * All functions in this category must use the macro
  * IO_CODE();
  * to catch when they are accidentally called by the wrong API.
  */

 int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
                        int64_t bytes, BdrvRequestFlags flags);
 int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
 int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int64_t bytes);
 int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf,
                 int64_t bytes);
 int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
                      const void *buf, int64_t bytes);
 /*
  * Efficiently zero a region of the disk image.  Note that this is a regular
  * I/O request like read or write and should have a reasonable size.  This
  * function is not suitable for zeroing the entire image in a single request
  * because it may allocate memory for the entire region.
  */
 int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
                                        int64_t bytes, BdrvRequestFlags flags);

 int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, bool exact,
                                   PreallocMode prealloc, BdrvRequestFlags flags,
                                   Error **errp);

 int64_t bdrv_nb_sectors(BlockDriverState *bs);
 int64_t bdrv_getlength(BlockDriverState *bs);
 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
 BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts,
                                BlockDriverState *in_bs, Error **errp);
 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
 int coroutine_fn bdrv_co_delete_file(BlockDriverState *bs, Error **errp);
 void coroutine_fn bdrv_co_delete_file_noerr(BlockDriverState *bs);


 /* async block I/O */
 void bdrv_aio_cancel(BlockAIOCB *acb);
 void bdrv_aio_cancel_async(BlockAIOCB *acb);

 /* sg packet commands */
 int bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf);

 /* Ensure contents are flushed to disk.  */
 int coroutine_fn bdrv_co_flush(BlockDriverState *bs);

 int bdrv_co_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
 int bdrv_block_status(BlockDriverState *bs, int64_t offset,
                       int64_t bytes, int64_t *pnum, int64_t *map,
                       BlockDriverState **file);
 int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
                             int64_t offset, int64_t bytes, int64_t *pnum,
                             int64_t *map, BlockDriverState **file);
 int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,
                       int64_t *pnum);
 int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
                             bool include_base, int64_t offset, int64_t bytes,
                             int64_t *pnum);
 int coroutine_fn bdrv_co_is_zero_fast(BlockDriverState *bs, int64_t offset,
                                       int64_t bytes);

 int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
                            bool ignore_allow_rdw, Error **errp);
 int bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg,
                               Error **errp);
 bool bdrv_is_read_only(BlockDriverState *bs);
 bool bdrv_is_writable(BlockDriverState *bs);
 bool bdrv_is_sg(BlockDriverState *bs);
 int bdrv_get_flags(BlockDriverState *bs);
 bool bdrv_is_inserted(BlockDriverState *bs);
 void bdrv_lock_medium(BlockDriverState *bs, bool locked);
 void bdrv_eject(BlockDriverState *bs, bool eject_flag);
 const char *bdrv_get_format_name(BlockDriverState *bs);

 bool bdrv_supports_compressed_writes(BlockDriverState *bs);
 const char *bdrv_get_node_name(const BlockDriverState *bs);
 const char *bdrv_get_device_name(const BlockDriverState *bs);
 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs);
 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs,
                                           Error **errp);
 BlockStatsSpecific *bdrv_get_specific_stats(BlockDriverState *bs);
 void bdrv_round_to_clusters(BlockDriverState *bs,
                             int64_t offset, int64_t bytes,
                             int64_t *cluster_offset,
                             int64_t *cluster_bytes);

 void bdrv_get_backing_filename(BlockDriverState *bs,
                                char *filename, int filename_size);

 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
                       int64_t pos, int size);

 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
                       int64_t pos, int size);

 /*
  * Returns the alignment in bytes that is required so that no bounce buffer
  * is required throughout the stack
  */
 size_t bdrv_min_mem_align(BlockDriverState *bs);
 /* Returns optimal alignment in bytes for bounce buffer */
 size_t bdrv_opt_mem_align(BlockDriverState *bs);
 void *qemu_blockalign(BlockDriverState *bs, size_t size);
 void *qemu_blockalign0(BlockDriverState *bs, size_t size);
 void *qemu_try_blockalign(BlockDriverState *bs, size_t size);
 void *qemu_try_blockalign0(BlockDriverState *bs, size_t size);
 bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov);

 void bdrv_enable_copy_on_read(BlockDriverState *bs);
 void bdrv_disable_copy_on_read(BlockDriverState *bs);

 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);

 #define BLKDBG_EVENT(child, evt) \
     do { \
         if (child) { \
             bdrv_debug_event(child->bs, evt); \
         } \
     } while (0)

 /**
  * bdrv_get_aio_context:
  *
  * Returns: the currently bound #AioContext
  */
 AioContext *bdrv_get_aio_context(BlockDriverState *bs);

 /**
  * Move the current coroutine to the AioContext of @bs and return the old
  * AioContext of the coroutine. Increase bs->in_flight so that draining @bs
  * will wait for the operation to proceed until the corresponding
  * bdrv_co_leave().
  *
  * Consequently, you can't call drain inside a bdrv_co_enter/leave() section as
  * this will deadlock.
  */
 AioContext *coroutine_fn bdrv_co_enter(BlockDriverState *bs);

 /**
  * Ends a section started by bdrv_co_enter(). Move the current coroutine back
  * to old_ctx and decrease bs->in_flight again.
  */
 void coroutine_fn bdrv_co_leave(BlockDriverState *bs, AioContext *old_ctx);

 /**
  * Transfer control to @co in the aio context of @bs
  */
 void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co);

 AioContext *child_of_bds_get_parent_aio_context(BdrvChild *c);

 void bdrv_io_plug(BlockDriverState *bs);
 void bdrv_io_unplug(BlockDriverState *bs);

 bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
                                      uint32_t granularity, Error **errp);

 /**
  *
  * bdrv_co_copy_range:
  *
  * Do offloaded copy between two children. If the operation is not implemented
  * by the driver, or if the backend storage doesn't support it, a negative
  * error code will be returned.
  *
  * Note: block layer doesn't emulate or fallback to a bounce buffer approach
  * because usually the caller shouldn't attempt offloaded copy any more (e.g.
  * calling copy_file_range(2)) after the first error, thus it should fall back
  * to a read+write path in the caller level.
  *
  * @src: Source child to copy data from
  * @src_offset: offset in @src image to read data
  * @dst: Destination child to copy data to
  * @dst_offset: offset in @dst image to write data
  * @bytes: number of bytes to copy
  * @flags: request flags. Supported flags:
  *         BDRV_REQ_ZERO_WRITE - treat the @src range as zero data and do zero
  *                               write on @dst as if bdrv_co_pwrite_zeroes is
  *                               called. Used to simplify caller code, or
  *                               during BlockDriver.bdrv_co_copy_range_from()
  *                               recursion.
  *         BDRV_REQ_NO_SERIALISING - do not serialize with other overlapping
  *                                   requests currently in flight.
  *
  * Returns: 0 if succeeded; negative error code if failed.
  **/
 int coroutine_fn bdrv_co_copy_range(BdrvChild *src, int64_t src_offset,
                                     BdrvChild *dst, int64_t dst_offset,
                                     int64_t bytes, BdrvRequestFlags read_flags,
                                     BdrvRequestFlags write_flags);

 /**
  * bdrv_drained_end_no_poll:
  *
  * Same as bdrv_drained_end(), but do not poll for the subgraph to
  * actually become unquiesced.  Therefore, no graph changes will occur
  * with this function.
  *
  * *drained_end_counter is incremented for every background operation
  * that is scheduled, and will be decremented for every operation once
  * it settles.  The caller must poll until it reaches 0.  The counter
  * should be accessed using atomic operations only.
  */
 void bdrv_drained_end_no_poll(BlockDriverState *bs, int *drained_end_counter);


 /*
  * "I/O or GS" API functions. These functions can run without
  * the BQL, but only in one specific iothread/main loop.
  *
  * More specifically, these functions use BDRV_POLL_WHILE(bs), which
  * requires the caller to be either in the main thread and hold
  * the BlockdriverState (bs) AioContext lock, or directly in the
  * home thread that runs the bs AioContext. Calling them from
  * another thread in another AioContext would cause deadlocks.
  *
  * Therefore, these functions are not proper I/O, because they
  * can't run in *any* iothreads, but only in a specific one.
  *
  * These functions can call any function from I/O, Common and this
  * categories, but must be invoked only by other "I/O or GS" and GS APIs.
  *
  * All functions in this category must use the macro
  * IO_OR_GS_CODE();
  * to catch when they are accidentally called by the wrong API.
  */

 #define BDRV_POLL_WHILE(bs, cond) ({                       \
     BlockDriverState *bs_ = (bs);                          \
     IO_OR_GS_CODE();                                       \
     AIO_WAIT_WHILE(bdrv_get_aio_context(bs_),              \
                    cond); })

 void bdrv_drain(BlockDriverState *bs);
 void coroutine_fn bdrv_co_drain(BlockDriverState *bs);

 int generated_co_wrapper
 bdrv_truncate(BdrvChild *child, int64_t offset, bool exact,
               PreallocMode prealloc, BdrvRequestFlags flags, Error **errp);

 int generated_co_wrapper bdrv_check(BlockDriverState *bs, BdrvCheckResult *res,
                                     BdrvCheckMode fix);

 /* Invalidate any cached metadata used by image formats */
 int generated_co_wrapper bdrv_invalidate_cache(BlockDriverState *bs,
                                                Error **errp);
 int generated_co_wrapper bdrv_flush(BlockDriverState *bs);
 int generated_co_wrapper bdrv_pdiscard(BdrvChild *child, int64_t offset,
                                        int64_t bytes);
 int generated_co_wrapper
 bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 int generated_co_wrapper
 bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);

 /**
  * bdrv_parent_drained_begin_single:
  *
  * Begin a quiesced section for the parent of @c. If @poll is true, wait for
  * any pending activity to cease.
  */
 void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll);

 /**
  * bdrv_parent_drained_end_single:
  *
  * End a quiesced section for the parent of @c.
  *
  * This polls @bs's AioContext until all scheduled sub-drained_ends
  * have settled, which may result in graph changes.
  */
 void bdrv_parent_drained_end_single(BdrvChild *c);

 /**
  * bdrv_drain_poll:
  *
  * Poll for pending requests in @bs, its parents (except for @ignore_parent),
  * and if @recursive is true its children as well (used for subtree drain).
  *
  * If @ignore_bds_parents is true, parents that are BlockDriverStates must
  * ignore the drain request because they will be drained separately (used for
  * drain_all).
  *
  * This is part of bdrv_drained_begin.
  */
 bool bdrv_drain_poll(BlockDriverState *bs, bool recursive,
                      BdrvChild *ignore_parent, bool ignore_bds_parents);

 /**
  * bdrv_drained_begin:
  *
  * Begin a quiesced section for exclusive access to the BDS, by disabling
  * external request sources including NBD server, block jobs, and device model.
  *
  * This function can be recursive.
  */
 void bdrv_drained_begin(BlockDriverState *bs);

 /**
  * bdrv_do_drained_begin_quiesce:
  *
  * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already
  * running requests to complete.
  */
 void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,
                                    BdrvChild *parent, bool ignore_bds_parents);

 /**
  * Like bdrv_drained_begin, but recursively begins a quiesced section for
  * exclusive access to all child nodes as well.
  */
 void bdrv_subtree_drained_begin(BlockDriverState *bs);

 /**
  * bdrv_drained_end:
  *
  * End a quiescent section started by bdrv_drained_begin().
  *
  * This polls @bs's AioContext until all scheduled sub-drained_ends
  * have settled.  On one hand, that may result in graph changes.  On
  * the other, this requires that the caller either runs in the main
  * loop; or that all involved nodes (@bs and all of its parents) are
  * in the caller's AioContext.
  */
 void bdrv_drained_end(BlockDriverState *bs);

 /**
  * End a quiescent section started by bdrv_subtree_drained_begin().
  */
 void bdrv_subtree_drained_end(BlockDriverState *bs);

 #endif /* BLOCK_IO_H */
	/*
	* QEMU System Emulator block driver
	*
	* Copyright (c) 2003 Fabrice Bellard
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	* THE SOFTWARE.
	*/
	#ifndef BLOCK_IO_H
	#define BLOCK_IO_H

	#include "block-common.h"

	/*
	* I/O API functions. These functions are thread-safe, and therefore
	* can run in any thread as long as the thread has called
	* aio_context_acquire/release().
	*
	* These functions can only call functions from I/O and Common categories,
	* but can be invoked by GS, "I/O or GS" and I/O APIs.
	*
	* All functions in this category must use the macro
	* IO_CODE();
	* to catch when they are accidentally called by the wrong API.
	*/

	int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
	int64_t bytes, BdrvRequestFlags flags);
	int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
	int bdrv_pread(BdrvChild child, int64_t offset, void buf, int64_t bytes);
	int bdrv_pwrite(BdrvChild child, int64_t offset, const void buf,
	int64_t bytes);
	int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
	const void *buf, int64_t bytes);
	/*
	* Efficiently zero a region of the disk image. Note that this is a regular
	* I/O request like read or write and should have a reasonable size. This
	* function is not suitable for zeroing the entire image in a single request
	* because it may allocate memory for the entire region.
	*/
	int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
	int64_t bytes, BdrvRequestFlags flags);

	int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, bool exact,
	PreallocMode prealloc, BdrvRequestFlags flags,
	Error **errp);

	int64_t bdrv_nb_sectors(BlockDriverState *bs);
	int64_t bdrv_getlength(BlockDriverState *bs);
	int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
	BlockMeasureInfo bdrv_measure(BlockDriver drv, QemuOpts *opts,
	BlockDriverState in_bs, Error *errp);
	void bdrv_get_geometry(BlockDriverState bs, uint64_t nb_sectors_ptr);
	int coroutine_fn bdrv_co_delete_file(BlockDriverState bs, Error *errp);
	void coroutine_fn bdrv_co_delete_file_noerr(BlockDriverState *bs);


	/* async block I/O */
	void bdrv_aio_cancel(BlockAIOCB *acb);
	void bdrv_aio_cancel_async(BlockAIOCB *acb);

	/* sg packet commands */
	int bdrv_co_ioctl(BlockDriverState bs, int req, void buf);

	/* Ensure contents are flushed to disk. */
	int coroutine_fn bdrv_co_flush(BlockDriverState *bs);

	int bdrv_co_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
	bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
	int bdrv_block_status(BlockDriverState *bs, int64_t offset,
	int64_t bytes, int64_t pnum, int64_t map,
	BlockDriverState **file);
	int bdrv_block_status_above(BlockDriverState bs, BlockDriverState base,
	int64_t offset, int64_t bytes, int64_t *pnum,
	int64_t map, BlockDriverState *file);
	int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,
	int64_t *pnum);
	int bdrv_is_allocated_above(BlockDriverState top, BlockDriverState base,
	bool include_base, int64_t offset, int64_t bytes,
	int64_t *pnum);
	int coroutine_fn bdrv_co_is_zero_fast(BlockDriverState *bs, int64_t offset,
	int64_t bytes);

	int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
	bool ignore_allow_rdw, Error **errp);
	int bdrv_apply_auto_read_only(BlockDriverState bs, const char errmsg,
	Error **errp);
	bool bdrv_is_read_only(BlockDriverState *bs);
	bool bdrv_is_writable(BlockDriverState *bs);
	bool bdrv_is_sg(BlockDriverState *bs);
	int bdrv_get_flags(BlockDriverState *bs);
	bool bdrv_is_inserted(BlockDriverState *bs);
	void bdrv_lock_medium(BlockDriverState *bs, bool locked);
	void bdrv_eject(BlockDriverState *bs, bool eject_flag);
	const char bdrv_get_format_name(BlockDriverState bs);

	bool bdrv_supports_compressed_writes(BlockDriverState *bs);
	const char bdrv_get_node_name(const BlockDriverState bs);
	const char bdrv_get_device_name(const BlockDriverState bs);
	const char bdrv_get_device_or_node_name(const BlockDriverState bs);
	int bdrv_get_info(BlockDriverState bs, BlockDriverInfo bdi);
	ImageInfoSpecific bdrv_get_specific_info(BlockDriverState bs,
	Error **errp);
	BlockStatsSpecific bdrv_get_specific_stats(BlockDriverState bs);
	void bdrv_round_to_clusters(BlockDriverState *bs,
	int64_t offset, int64_t bytes,
	int64_t *cluster_offset,
	int64_t *cluster_bytes);

	void bdrv_get_backing_filename(BlockDriverState *bs,
	char *filename, int filename_size);

	int bdrv_save_vmstate(BlockDriverState bs, const uint8_t buf,
	int64_t pos, int size);

	int bdrv_load_vmstate(BlockDriverState bs, uint8_t buf,
	int64_t pos, int size);

	/*
	* Returns the alignment in bytes that is required so that no bounce buffer
	* is required throughout the stack
	*/
	size_t bdrv_min_mem_align(BlockDriverState *bs);
	/* Returns optimal alignment in bytes for bounce buffer */
	size_t bdrv_opt_mem_align(BlockDriverState *bs);
	void qemu_blockalign(BlockDriverState bs, size_t size);
	void qemu_blockalign0(BlockDriverState bs, size_t size);
	void qemu_try_blockalign(BlockDriverState bs, size_t size);
	void qemu_try_blockalign0(BlockDriverState bs, size_t size);
	bool bdrv_qiov_is_aligned(BlockDriverState bs, QEMUIOVector qiov);

	void bdrv_enable_copy_on_read(BlockDriverState *bs);
	void bdrv_disable_copy_on_read(BlockDriverState *bs);

	void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);

	#define BLKDBG_EVENT(child, evt) \
	do { \
	if (child) { \
	bdrv_debug_event(child->bs, evt); \
	} \
	} while (0)

	/**
	* bdrv_get_aio_context:
	*
	* Returns: the currently bound #AioContext
	*/
	AioContext bdrv_get_aio_context(BlockDriverState bs);

	/**
	* Move the current coroutine to the AioContext of @bs and return the old
	* AioContext of the coroutine. Increase bs->in_flight so that draining @bs
	* will wait for the operation to proceed until the corresponding
	* bdrv_co_leave().
	*
	* Consequently, you can't call drain inside a bdrv_co_enter/leave() section as
	* this will deadlock.
	*/
	AioContext coroutine_fn bdrv_co_enter(BlockDriverState bs);

	/**
	* Ends a section started by bdrv_co_enter(). Move the current coroutine back
	* to old_ctx and decrease bs->in_flight again.
	*/
	void coroutine_fn bdrv_co_leave(BlockDriverState bs, AioContext old_ctx);

	/**
	* Transfer control to @co in the aio context of @bs
	*/
	void bdrv_coroutine_enter(BlockDriverState bs, Coroutine co);

	AioContext child_of_bds_get_parent_aio_context(BdrvChild c);

	void bdrv_io_plug(BlockDriverState *bs);
	void bdrv_io_unplug(BlockDriverState *bs);

	bool bdrv_can_store_new_dirty_bitmap(BlockDriverState bs, const char name,
	uint32_t granularity, Error **errp);

	/**
	*
	* bdrv_co_copy_range:
	*
	* Do offloaded copy between two children. If the operation is not implemented
	* by the driver, or if the backend storage doesn't support it, a negative
	* error code will be returned.
	*
	* Note: block layer doesn't emulate or fallback to a bounce buffer approach
	* because usually the caller shouldn't attempt offloaded copy any more (e.g.
	* calling copy_file_range(2)) after the first error, thus it should fall back
	* to a read+write path in the caller level.
	*
	* @src: Source child to copy data from
	* @src_offset: offset in @src image to read data
	* @dst: Destination child to copy data to
	* @dst_offset: offset in @dst image to write data
	* @bytes: number of bytes to copy
	* @flags: request flags. Supported flags:
	* BDRV_REQ_ZERO_WRITE - treat the @src range as zero data and do zero
	* write on @dst as if bdrv_co_pwrite_zeroes is
	* called. Used to simplify caller code, or
	* during BlockDriver.bdrv_co_copy_range_from()
	* recursion.
	* BDRV_REQ_NO_SERIALISING - do not serialize with other overlapping
	* requests currently in flight.
	*
	* Returns: 0 if succeeded; negative error code if failed.
	**/
	int coroutine_fn bdrv_co_copy_range(BdrvChild *src, int64_t src_offset,
	BdrvChild *dst, int64_t dst_offset,
	int64_t bytes, BdrvRequestFlags read_flags,
	BdrvRequestFlags write_flags);

	/**
	* bdrv_drained_end_no_poll:
	*
	* Same as bdrv_drained_end(), but do not poll for the subgraph to
	* actually become unquiesced. Therefore, no graph changes will occur
	* with this function.
	*
	* *drained_end_counter is incremented for every background operation
	* that is scheduled, and will be decremented for every operation once
	* it settles. The caller must poll until it reaches 0. The counter
	* should be accessed using atomic operations only.
	*/
	void bdrv_drained_end_no_poll(BlockDriverState bs, int drained_end_counter);


	/*
	* "I/O or GS" API functions. These functions can run without
	* the BQL, but only in one specific iothread/main loop.
	*
	* More specifically, these functions use BDRV_POLL_WHILE(bs), which
	* requires the caller to be either in the main thread and hold
	* the BlockdriverState (bs) AioContext lock, or directly in the
	* home thread that runs the bs AioContext. Calling them from
	* another thread in another AioContext would cause deadlocks.
	*
	* Therefore, these functions are not proper I/O, because they
	* can't run in any iothreads, but only in a specific one.
	*
	* These functions can call any function from I/O, Common and this
	* categories, but must be invoked only by other "I/O or GS" and GS APIs.
	*
	* All functions in this category must use the macro
	* IO_OR_GS_CODE();
	* to catch when they are accidentally called by the wrong API.
	*/

	#define BDRV_POLL_WHILE(bs, cond) ({ \
	BlockDriverState *bs_ = (bs); \
	IO_OR_GS_CODE(); \
	AIO_WAIT_WHILE(bdrv_get_aio_context(bs_), \
	cond); })

	void bdrv_drain(BlockDriverState *bs);
	void coroutine_fn bdrv_co_drain(BlockDriverState *bs);

	int generated_co_wrapper
	bdrv_truncate(BdrvChild *child, int64_t offset, bool exact,
	PreallocMode prealloc, BdrvRequestFlags flags, Error **errp);

	int generated_co_wrapper bdrv_check(BlockDriverState bs, BdrvCheckResult res,
	BdrvCheckMode fix);

	/* Invalidate any cached metadata used by image formats */
	int generated_co_wrapper bdrv_invalidate_cache(BlockDriverState *bs,
	Error **errp);
	int generated_co_wrapper bdrv_flush(BlockDriverState *bs);
	int generated_co_wrapper bdrv_pdiscard(BdrvChild *child, int64_t offset,
	int64_t bytes);
	int generated_co_wrapper
	bdrv_readv_vmstate(BlockDriverState bs, QEMUIOVector qiov, int64_t pos);
	int generated_co_wrapper
	bdrv_writev_vmstate(BlockDriverState bs, QEMUIOVector qiov, int64_t pos);

	/**
	* bdrv_parent_drained_begin_single:
	*
	* Begin a quiesced section for the parent of @c. If @poll is true, wait for
	* any pending activity to cease.
	*/
	void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll);

	/**
	* bdrv_parent_drained_end_single:
	*
	* End a quiesced section for the parent of @c.
	*
	* This polls @bs's AioContext until all scheduled sub-drained_ends
	* have settled, which may result in graph changes.
	*/
	void bdrv_parent_drained_end_single(BdrvChild *c);

	/**
	* bdrv_drain_poll:
	*
	* Poll for pending requests in @bs, its parents (except for @ignore_parent),
	* and if @recursive is true its children as well (used for subtree drain).
	*
	* If @ignore_bds_parents is true, parents that are BlockDriverStates must
	* ignore the drain request because they will be drained separately (used for
	* drain_all).
	*
	* This is part of bdrv_drained_begin.
	*/
	bool bdrv_drain_poll(BlockDriverState *bs, bool recursive,
	BdrvChild *ignore_parent, bool ignore_bds_parents);

	/**
	* bdrv_drained_begin:
	*
	* Begin a quiesced section for exclusive access to the BDS, by disabling
	* external request sources including NBD server, block jobs, and device model.
	*
	* This function can be recursive.
	*/
	void bdrv_drained_begin(BlockDriverState *bs);

	/**
	* bdrv_do_drained_begin_quiesce:
	*
	* Quiesces a BDS like bdrv_drained_begin(), but does not wait for already
	* running requests to complete.
	*/
	void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,
	BdrvChild *parent, bool ignore_bds_parents);

	/**
	* Like bdrv_drained_begin, but recursively begins a quiesced section for
	* exclusive access to all child nodes as well.
	*/
	void bdrv_subtree_drained_begin(BlockDriverState *bs);

	/**
	* bdrv_drained_end:
	*
	* End a quiescent section started by bdrv_drained_begin().
	*
	* This polls @bs's AioContext until all scheduled sub-drained_ends
	* have settled. On one hand, that may result in graph changes. On
	* the other, this requires that the caller either runs in the main
	* loop; or that all involved nodes (@bs and all of its parents) are
	* in the caller's AioContext.
	*/
	void bdrv_drained_end(BlockDriverState *bs);

	/**
	* End a quiescent section started by bdrv_subtree_drained_begin().
	*/
	void bdrv_subtree_drained_end(BlockDriverState *bs);

	#endif /* BLOCK_IO_H */