qemu/include/block/block_int-io.h
Emanuele Giuseppe Esposito c86422c554 block: Convert bdrv_refresh_total_sectors() to co_wrapper_mixed
BlockDriver->bdrv_getlength is categorized as IO callback, and it
currently doesn't run in a coroutine. We should let it take a graph
rdlock since the callback traverses the block nodes graph, which however
is only possible in a coroutine.

Therefore turn it into a co_wrapper to move the actual function into a
coroutine where the lock can be taken.

Because now this function creates a new coroutine and polls, we need to
take the AioContext lock where it is missing, for the only reason that
internally co_wrapper calls AIO_WAIT_WHILE and it expects to release the
AioContext lock.

This is especially messy when a co_wrapper creates a coroutine and polls
in bdrv_open_driver, because this function has so many callers in so
many context that it can easily lead to deadlocks. Therefore the new
rule for bdrv_open_driver is that the caller must always hold the
AioContext lock of the given bs (except if it is a coroutine), because
the function calls bdrv_refresh_total_sectors() which is now a
co_wrapper.

Once the rwlock is ultimated and placed in every place it needs to be,
we will poll using AIO_WAIT_WHILE_UNLOCKED and remove the AioContext
lock.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230113204212.359076-7-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-02-01 16:52:32 +01:00

188 lines
7.0 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_INT_IO_H
#define BLOCK_INT_IO_H
#include "block/block_int-common.h"
#include "qemu/hbitmap.h"
#include "qemu/main-loop.h"
/*
* I/O API functions. These functions are thread-safe.
*
* See include/block/block-io.h for more information about
* the I/O API.
*/
int coroutine_fn bdrv_co_preadv_snapshot(BdrvChild *child,
int64_t offset, int64_t bytes, QEMUIOVector *qiov, size_t qiov_offset);
int coroutine_fn bdrv_co_snapshot_block_status(BlockDriverState *bs,
bool want_zero, int64_t offset, int64_t bytes, int64_t *pnum,
int64_t *map, BlockDriverState **file);
int coroutine_fn bdrv_co_pdiscard_snapshot(BlockDriverState *bs,
int64_t offset, int64_t bytes);
int coroutine_fn bdrv_co_preadv(BdrvChild *child,
int64_t offset, int64_t bytes, QEMUIOVector *qiov,
BdrvRequestFlags flags);
int coroutine_fn bdrv_co_preadv_part(BdrvChild *child,
int64_t offset, int64_t bytes,
QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags);
int coroutine_fn bdrv_co_pwritev(BdrvChild *child,
int64_t offset, int64_t bytes, QEMUIOVector *qiov,
BdrvRequestFlags flags);
int coroutine_fn bdrv_co_pwritev_part(BdrvChild *child,
int64_t offset, int64_t bytes,
QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags);
static inline int coroutine_fn bdrv_co_pread(BdrvChild *child,
int64_t offset, int64_t bytes, void *buf, BdrvRequestFlags flags)
{
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
IO_CODE();
return bdrv_co_preadv(child, offset, bytes, &qiov, flags);
}
static inline int coroutine_fn bdrv_co_pwrite(BdrvChild *child,
int64_t offset, int64_t bytes, const void *buf, BdrvRequestFlags flags)
{
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
IO_CODE();
return bdrv_co_pwritev(child, offset, bytes, &qiov, flags);
}
void coroutine_fn bdrv_make_request_serialising(BdrvTrackedRequest *req,
uint64_t align);
BdrvTrackedRequest *coroutine_fn bdrv_co_get_self_request(BlockDriverState *bs);
BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size,
const char *filename);
/**
* bdrv_wakeup:
* @bs: The BlockDriverState for which an I/O operation has been completed.
*
* Wake up the main thread if it is waiting on BDRV_POLL_WHILE. During
* synchronous I/O on a BlockDriverState that is attached to another
* I/O thread, the main thread lets the I/O thread's event loop run,
* waiting for the I/O operation to complete. A bdrv_wakeup will wake
* up the main thread if necessary.
*
* Manual calls to bdrv_wakeup are rarely necessary, because
* bdrv_dec_in_flight already calls it.
*/
void bdrv_wakeup(BlockDriverState *bs);
const char *bdrv_get_parent_name(const BlockDriverState *bs);
bool blk_dev_has_tray(BlockBackend *blk);
bool blk_dev_is_tray_open(BlockBackend *blk);
void bdrv_set_dirty(BlockDriverState *bs, int64_t offset, int64_t bytes);
void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out);
void bdrv_dirty_bitmap_merge_internal(BdrvDirtyBitmap *dest,
const BdrvDirtyBitmap *src,
HBitmap **backup, bool lock);
void bdrv_inc_in_flight(BlockDriverState *bs);
void bdrv_dec_in_flight(BlockDriverState *bs);
int coroutine_fn bdrv_co_copy_range_from(BdrvChild *src, int64_t src_offset,
BdrvChild *dst, int64_t dst_offset,
int64_t bytes,
BdrvRequestFlags read_flags,
BdrvRequestFlags write_flags);
int coroutine_fn bdrv_co_copy_range_to(BdrvChild *src, int64_t src_offset,
BdrvChild *dst, int64_t dst_offset,
int64_t bytes,
BdrvRequestFlags read_flags,
BdrvRequestFlags write_flags);
int coroutine_fn bdrv_co_refresh_total_sectors(BlockDriverState *bs,
int64_t hint);
int co_wrapper_mixed
bdrv_refresh_total_sectors(BlockDriverState *bs, int64_t hint);
BdrvChild *bdrv_cow_child(BlockDriverState *bs);
BdrvChild *bdrv_filter_child(BlockDriverState *bs);
BdrvChild *bdrv_filter_or_cow_child(BlockDriverState *bs);
BdrvChild *bdrv_primary_child(BlockDriverState *bs);
BlockDriverState *bdrv_skip_filters(BlockDriverState *bs);
BlockDriverState *bdrv_backing_chain_next(BlockDriverState *bs);
static inline BlockDriverState *bdrv_cow_bs(BlockDriverState *bs)
{
IO_CODE();
return child_bs(bdrv_cow_child(bs));
}
static inline BlockDriverState *bdrv_filter_bs(BlockDriverState *bs)
{
IO_CODE();
return child_bs(bdrv_filter_child(bs));
}
static inline BlockDriverState *bdrv_filter_or_cow_bs(BlockDriverState *bs)
{
IO_CODE();
return child_bs(bdrv_filter_or_cow_child(bs));
}
static inline BlockDriverState *bdrv_primary_bs(BlockDriverState *bs)
{
IO_CODE();
return child_bs(bdrv_primary_child(bs));
}
/**
* Check whether the given offset is in the cached block-status data
* region.
*
* If it is, and @pnum is not NULL, *pnum is set to
* `bsc.data_end - offset`, i.e. how many bytes, starting from
* @offset, are data (according to the cache).
* Otherwise, *pnum is not touched.
*/
bool bdrv_bsc_is_data(BlockDriverState *bs, int64_t offset, int64_t *pnum);
/**
* If [offset, offset + bytes) overlaps with the currently cached
* block-status region, invalidate the cache.
*
* (To be used by I/O paths that cause data regions to be zero or
* holes.)
*/
void bdrv_bsc_invalidate_range(BlockDriverState *bs,
int64_t offset, int64_t bytes);
/**
* Mark the range [offset, offset + bytes) as a data region.
*/
void bdrv_bsc_fill(BlockDriverState *bs, int64_t offset, int64_t bytes);
#endif /* BLOCK_INT_IO_H */