370 lines
15 KiB
C
370 lines
15 KiB
C
/*
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* QEMU System Emulator block driver
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*
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* Copyright (c) 2003 Fabrice Bellard
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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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#ifndef BLOCK_IO_H
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#define BLOCK_IO_H
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#include "block-common.h"
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/*
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* I/O API functions. These functions are thread-safe, and therefore
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* can run in any thread as long as the thread has called
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* aio_context_acquire/release().
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*
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* These functions can only call functions from I/O and Common categories,
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* but can be invoked by GS, "I/O or GS" and I/O APIs.
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*
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* All functions in this category must use the macro
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* IO_CODE();
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* to catch when they are accidentally called by the wrong API.
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*/
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int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
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int64_t bytes, BdrvRequestFlags flags);
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int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
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int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int64_t bytes);
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int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf,
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int64_t bytes);
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int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
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const void *buf, int64_t bytes);
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/*
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* Efficiently zero a region of the disk image. Note that this is a regular
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* I/O request like read or write and should have a reasonable size. This
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* function is not suitable for zeroing the entire image in a single request
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* because it may allocate memory for the entire region.
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*/
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int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
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int64_t bytes, BdrvRequestFlags flags);
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int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, bool exact,
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PreallocMode prealloc, BdrvRequestFlags flags,
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Error **errp);
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int64_t bdrv_nb_sectors(BlockDriverState *bs);
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int64_t bdrv_getlength(BlockDriverState *bs);
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int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
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BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts,
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BlockDriverState *in_bs, Error **errp);
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void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
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int coroutine_fn bdrv_co_delete_file(BlockDriverState *bs, Error **errp);
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void coroutine_fn bdrv_co_delete_file_noerr(BlockDriverState *bs);
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/* async block I/O */
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void bdrv_aio_cancel(BlockAIOCB *acb);
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void bdrv_aio_cancel_async(BlockAIOCB *acb);
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/* sg packet commands */
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int bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf);
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/* Ensure contents are flushed to disk. */
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int coroutine_fn bdrv_co_flush(BlockDriverState *bs);
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int bdrv_co_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
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bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
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int bdrv_block_status(BlockDriverState *bs, int64_t offset,
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int64_t bytes, int64_t *pnum, int64_t *map,
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BlockDriverState **file);
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int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
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int64_t offset, int64_t bytes, int64_t *pnum,
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int64_t *map, BlockDriverState **file);
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int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,
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int64_t *pnum);
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int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
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bool include_base, int64_t offset, int64_t bytes,
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int64_t *pnum);
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int coroutine_fn bdrv_co_is_zero_fast(BlockDriverState *bs, int64_t offset,
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int64_t bytes);
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int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
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bool ignore_allow_rdw, Error **errp);
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int bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg,
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Error **errp);
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bool bdrv_is_read_only(BlockDriverState *bs);
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bool bdrv_is_writable(BlockDriverState *bs);
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bool bdrv_is_sg(BlockDriverState *bs);
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int bdrv_get_flags(BlockDriverState *bs);
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bool bdrv_is_inserted(BlockDriverState *bs);
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void bdrv_lock_medium(BlockDriverState *bs, bool locked);
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void bdrv_eject(BlockDriverState *bs, bool eject_flag);
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const char *bdrv_get_format_name(BlockDriverState *bs);
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bool bdrv_supports_compressed_writes(BlockDriverState *bs);
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const char *bdrv_get_node_name(const BlockDriverState *bs);
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const char *bdrv_get_device_name(const BlockDriverState *bs);
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const char *bdrv_get_device_or_node_name(const BlockDriverState *bs);
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int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
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ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs,
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Error **errp);
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BlockStatsSpecific *bdrv_get_specific_stats(BlockDriverState *bs);
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void bdrv_round_to_clusters(BlockDriverState *bs,
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int64_t offset, int64_t bytes,
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int64_t *cluster_offset,
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int64_t *cluster_bytes);
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void bdrv_get_backing_filename(BlockDriverState *bs,
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char *filename, int filename_size);
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int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
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int64_t pos, int size);
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int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
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int64_t pos, int size);
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/*
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* Returns the alignment in bytes that is required so that no bounce buffer
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* is required throughout the stack
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*/
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size_t bdrv_min_mem_align(BlockDriverState *bs);
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/* Returns optimal alignment in bytes for bounce buffer */
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size_t bdrv_opt_mem_align(BlockDriverState *bs);
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void *qemu_blockalign(BlockDriverState *bs, size_t size);
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void *qemu_blockalign0(BlockDriverState *bs, size_t size);
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void *qemu_try_blockalign(BlockDriverState *bs, size_t size);
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void *qemu_try_blockalign0(BlockDriverState *bs, size_t size);
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bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov);
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void bdrv_enable_copy_on_read(BlockDriverState *bs);
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void bdrv_disable_copy_on_read(BlockDriverState *bs);
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void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);
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#define BLKDBG_EVENT(child, evt) \
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do { \
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if (child) { \
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bdrv_debug_event(child->bs, evt); \
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} \
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} while (0)
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/**
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* bdrv_get_aio_context:
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*
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* Returns: the currently bound #AioContext
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*/
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AioContext *bdrv_get_aio_context(BlockDriverState *bs);
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/**
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* Move the current coroutine to the AioContext of @bs and return the old
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* AioContext of the coroutine. Increase bs->in_flight so that draining @bs
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* will wait for the operation to proceed until the corresponding
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* bdrv_co_leave().
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*
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* Consequently, you can't call drain inside a bdrv_co_enter/leave() section as
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* this will deadlock.
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*/
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AioContext *coroutine_fn bdrv_co_enter(BlockDriverState *bs);
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/**
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* Ends a section started by bdrv_co_enter(). Move the current coroutine back
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* to old_ctx and decrease bs->in_flight again.
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*/
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void coroutine_fn bdrv_co_leave(BlockDriverState *bs, AioContext *old_ctx);
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/**
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* Transfer control to @co in the aio context of @bs
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*/
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void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co);
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AioContext *child_of_bds_get_parent_aio_context(BdrvChild *c);
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void bdrv_io_plug(BlockDriverState *bs);
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void bdrv_io_unplug(BlockDriverState *bs);
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bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
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uint32_t granularity, Error **errp);
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/**
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*
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* bdrv_co_copy_range:
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*
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* Do offloaded copy between two children. If the operation is not implemented
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* by the driver, or if the backend storage doesn't support it, a negative
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* error code will be returned.
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*
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* Note: block layer doesn't emulate or fallback to a bounce buffer approach
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* because usually the caller shouldn't attempt offloaded copy any more (e.g.
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* calling copy_file_range(2)) after the first error, thus it should fall back
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* to a read+write path in the caller level.
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*
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* @src: Source child to copy data from
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* @src_offset: offset in @src image to read data
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* @dst: Destination child to copy data to
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* @dst_offset: offset in @dst image to write data
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* @bytes: number of bytes to copy
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* @flags: request flags. Supported flags:
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* BDRV_REQ_ZERO_WRITE - treat the @src range as zero data and do zero
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* write on @dst as if bdrv_co_pwrite_zeroes is
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* called. Used to simplify caller code, or
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* during BlockDriver.bdrv_co_copy_range_from()
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* recursion.
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* BDRV_REQ_NO_SERIALISING - do not serialize with other overlapping
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* requests currently in flight.
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*
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* Returns: 0 if succeeded; negative error code if failed.
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**/
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int coroutine_fn bdrv_co_copy_range(BdrvChild *src, int64_t src_offset,
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BdrvChild *dst, int64_t dst_offset,
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int64_t bytes, BdrvRequestFlags read_flags,
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BdrvRequestFlags write_flags);
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/**
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* bdrv_drained_end_no_poll:
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*
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* Same as bdrv_drained_end(), but do not poll for the subgraph to
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* actually become unquiesced. Therefore, no graph changes will occur
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* with this function.
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*
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* *drained_end_counter is incremented for every background operation
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* that is scheduled, and will be decremented for every operation once
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* it settles. The caller must poll until it reaches 0. The counter
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* should be accessed using atomic operations only.
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*/
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void bdrv_drained_end_no_poll(BlockDriverState *bs, int *drained_end_counter);
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/*
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* "I/O or GS" API functions. These functions can run without
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* the BQL, but only in one specific iothread/main loop.
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*
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* More specifically, these functions use BDRV_POLL_WHILE(bs), which
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* requires the caller to be either in the main thread and hold
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* the BlockdriverState (bs) AioContext lock, or directly in the
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* home thread that runs the bs AioContext. Calling them from
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* another thread in another AioContext would cause deadlocks.
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*
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* Therefore, these functions are not proper I/O, because they
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* can't run in *any* iothreads, but only in a specific one.
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*
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* These functions can call any function from I/O, Common and this
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* categories, but must be invoked only by other "I/O or GS" and GS APIs.
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*
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* All functions in this category must use the macro
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* IO_OR_GS_CODE();
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* to catch when they are accidentally called by the wrong API.
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*/
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#define BDRV_POLL_WHILE(bs, cond) ({ \
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BlockDriverState *bs_ = (bs); \
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IO_OR_GS_CODE(); \
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AIO_WAIT_WHILE(bdrv_get_aio_context(bs_), \
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cond); })
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void bdrv_drain(BlockDriverState *bs);
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void coroutine_fn bdrv_co_drain(BlockDriverState *bs);
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int generated_co_wrapper
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bdrv_truncate(BdrvChild *child, int64_t offset, bool exact,
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PreallocMode prealloc, BdrvRequestFlags flags, Error **errp);
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int generated_co_wrapper bdrv_check(BlockDriverState *bs, BdrvCheckResult *res,
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BdrvCheckMode fix);
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/* Invalidate any cached metadata used by image formats */
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int generated_co_wrapper bdrv_invalidate_cache(BlockDriverState *bs,
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Error **errp);
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int generated_co_wrapper bdrv_flush(BlockDriverState *bs);
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int generated_co_wrapper bdrv_pdiscard(BdrvChild *child, int64_t offset,
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int64_t bytes);
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int generated_co_wrapper
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bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
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int generated_co_wrapper
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bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
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/**
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* bdrv_parent_drained_begin_single:
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*
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* Begin a quiesced section for the parent of @c. If @poll is true, wait for
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* any pending activity to cease.
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*/
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void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll);
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/**
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* bdrv_parent_drained_end_single:
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*
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* End a quiesced section for the parent of @c.
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*
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* This polls @bs's AioContext until all scheduled sub-drained_ends
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* have settled, which may result in graph changes.
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*/
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void bdrv_parent_drained_end_single(BdrvChild *c);
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/**
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* bdrv_drain_poll:
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*
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* Poll for pending requests in @bs, its parents (except for @ignore_parent),
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* and if @recursive is true its children as well (used for subtree drain).
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*
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* If @ignore_bds_parents is true, parents that are BlockDriverStates must
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* ignore the drain request because they will be drained separately (used for
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* drain_all).
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*
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* This is part of bdrv_drained_begin.
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*/
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bool bdrv_drain_poll(BlockDriverState *bs, bool recursive,
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BdrvChild *ignore_parent, bool ignore_bds_parents);
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/**
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* bdrv_drained_begin:
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*
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* Begin a quiesced section for exclusive access to the BDS, by disabling
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* external request sources including NBD server, block jobs, and device model.
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*
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* This function can be recursive.
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*/
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void bdrv_drained_begin(BlockDriverState *bs);
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/**
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* bdrv_do_drained_begin_quiesce:
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*
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* Quiesces a BDS like bdrv_drained_begin(), but does not wait for already
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* running requests to complete.
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*/
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void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,
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BdrvChild *parent, bool ignore_bds_parents);
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/**
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* Like bdrv_drained_begin, but recursively begins a quiesced section for
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* exclusive access to all child nodes as well.
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*/
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void bdrv_subtree_drained_begin(BlockDriverState *bs);
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/**
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* bdrv_drained_end:
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*
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* End a quiescent section started by bdrv_drained_begin().
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*
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* This polls @bs's AioContext until all scheduled sub-drained_ends
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* have settled. On one hand, that may result in graph changes. On
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* the other, this requires that the caller either runs in the main
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* loop; or that all involved nodes (@bs and all of its parents) are
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* in the caller's AioContext.
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*/
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void bdrv_drained_end(BlockDriverState *bs);
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/**
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* End a quiescent section started by bdrv_subtree_drained_begin().
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*/
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void bdrv_subtree_drained_end(BlockDriverState *bs);
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#endif /* BLOCK_IO_H */
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