/* * 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); 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 */