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Diffstat (limited to 'include/block/block-io.h')
| -rw-r--r-- | include/block/block-io.h | 367 |
1 files changed, 367 insertions, 0 deletions
diff --git a/include/block/block-io.h b/include/block/block-io.h new file mode 100644 index 0000000000..2cbdfb92c9 --- /dev/null +++ b/include/block/block-io.h @@ -0,0 +1,367 @@ +/* + * 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); +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); \ + 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 */ |