qemu-e2k/include/block/block-io.h

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/*
* 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/aio-wait.h"
#include "block/block-common.h"
#include "qemu/coroutine.h"
#include "qemu/iov.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 co_wrapper_mixed_bdrv_rdlock
bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset, int64_t bytes,
BdrvRequestFlags flags);
int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
int co_wrapper_mixed_bdrv_rdlock
bdrv_pread(BdrvChild *child, int64_t offset, int64_t bytes, void *buf,
BdrvRequestFlags flags);
int co_wrapper_mixed_bdrv_rdlock
bdrv_pwrite(BdrvChild *child, int64_t offset,int64_t bytes,
const void *buf, BdrvRequestFlags flags);
int co_wrapper_mixed_bdrv_rdlock
bdrv_pwrite_sync(BdrvChild *child, int64_t offset, int64_t bytes,
const void *buf, BdrvRequestFlags flags);
int coroutine_fn bdrv_co_pwrite_sync(BdrvChild *child, int64_t offset,
int64_t bytes, const void *buf,
BdrvRequestFlags flags);
/*
* 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 coroutine_fn bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf);
/* Ensure contents are flushed to disk. */
int coroutine_fn bdrv_co_flush(BlockDriverState *bs);
int coroutine_fn 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 coroutine_fn bdrv_co_block_status_above(BlockDriverState *bs,
BlockDriverState *base,
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 coroutine_fn bdrv_co_is_allocated(BlockDriverState *bs, int64_t offset,
int64_t bytes, int64_t *pnum);
int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,
int64_t *pnum);
int coroutine_fn bdrv_co_is_allocated_above(BlockDriverState *top,
BlockDriverState *base,
bool include_base, 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);
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);
AioContext *bdrv_child_get_parent_aio_context(BdrvChild *c);
/**
* 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);
AioContext *child_of_bds_get_parent_aio_context(BdrvChild *c);
void coroutine_fn bdrv_co_io_plug(BlockDriverState *bs);
void bdrv_io_unplug(BlockDriverState *bs);
bool coroutine_fn bdrv_co_can_store_new_dirty_bitmap(BlockDriverState *bs,
const char *name,
uint32_t granularity,
Error **errp);
bool co_wrapper 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);
/*
* "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);
int co_wrapper_mixed_bdrv_rdlock
bdrv_truncate(BdrvChild *child, int64_t offset, bool exact,
PreallocMode prealloc, BdrvRequestFlags flags, Error **errp);
int co_wrapper_mixed_bdrv_rdlock
bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
/* Invalidate any cached metadata used by image formats */
int co_wrapper_mixed_bdrv_rdlock
bdrv_invalidate_cache(BlockDriverState *bs, Error **errp);
int co_wrapper_mixed_bdrv_rdlock bdrv_flush(BlockDriverState *bs);
int co_wrapper_mixed_bdrv_rdlock
bdrv_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
int co_wrapper_mixed_bdrv_rdlock
bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
int co_wrapper_mixed_bdrv_rdlock
bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
/**
* bdrv_parent_drained_begin_single:
*
* Begin a quiesced section for the parent of @c.
*/
void bdrv_parent_drained_begin_single(BdrvChild *c);
/**
* bdrv_parent_drained_poll_single:
*
* Returns true if there is any pending activity to cease before @c can be
* called quiesced, false otherwise.
*/
bool bdrv_parent_drained_poll_single(BdrvChild *c);
/**
* bdrv_parent_drained_end_single:
*
* End a quiesced section for the parent of @c.
*/
void bdrv_parent_drained_end_single(BdrvChild *c);
/**
* bdrv_drain_poll:
*
* Poll for pending requests in @bs and its parents (except for @ignore_parent).
*
* 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, 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);
/**
* bdrv_drained_end:
*
* End a quiescent section started by bdrv_drained_begin().
*/
void bdrv_drained_end(BlockDriverState *bs);
#endif /* BLOCK_IO_H */