15aee7ac95
This function is safe to call in an I/O context, and qcow2_do_open() does so (invoked in an I/O context by qcow2_co_invalidate_cache()). Signed-off-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20220427114057.36651-2-hreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
370 lines
15 KiB
C
370 lines
15 KiB
C
/*
|
|
* 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 */
|