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block: Introduce a new API bdrv_co_no_copy_on_readv()

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In some cases, we need to disable copy-on-read, and just
read the data.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Message-id: 1441682913-14320-2-git-send-email-wency@cn.fujitsu.com
Signed-off-by: Jeff Cody <jcody@redhat.com>
This commit is contained in:
Wen Congyang 2015-09-08 11:28:32 +08:00 committed by Jeff Cody
parent 4da65c8092
commit 9568b511c9
3 changed files with 18 additions and 4 deletions
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12
block/io.c
View File

@ -932,7 +932,8 @@ static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs,
return ret; return ret;
} }
if (bs->copy_on_read) { /* Don't do copy-on-read if we read data before write operation */
if (bs->copy_on_read && !(flags & BDRV_REQ_NO_COPY_ON_READ)) {
flags |= BDRV_REQ_COPY_ON_READ; flags |= BDRV_REQ_COPY_ON_READ;
} }
@ -1001,6 +1002,15 @@ int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num,
return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov, 0); return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov, 0);
} }
int coroutine_fn bdrv_co_no_copy_on_readv(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
{
trace_bdrv_co_no_copy_on_readv(bs, sector_num, nb_sectors);
return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov,
BDRV_REQ_NO_COPY_ON_READ);
}
int coroutine_fn bdrv_co_copy_on_readv(BlockDriverState *bs, int coroutine_fn bdrv_co_copy_on_readv(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
{ {

9
include/block/block.h
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@ -51,15 +51,16 @@ typedef struct BlockFragInfo {
} BlockFragInfo; } BlockFragInfo;
typedef enum { typedef enum {
BDRV_REQ_COPY_ON_READ = 0x1, BDRV_REQ_COPY_ON_READ = 0x1,
BDRV_REQ_ZERO_WRITE = 0x2, BDRV_REQ_ZERO_WRITE = 0x2,
/* The BDRV_REQ_MAY_UNMAP flag is used to indicate that the block driver /* The BDRV_REQ_MAY_UNMAP flag is used to indicate that the block driver
* is allowed to optimize a write zeroes request by unmapping (discarding) * is allowed to optimize a write zeroes request by unmapping (discarding)
* blocks if it is guaranteed that the result will read back as * blocks if it is guaranteed that the result will read back as
* zeroes. The flag is only passed to the driver if the block device is * zeroes. The flag is only passed to the driver if the block device is
* opened with BDRV_O_UNMAP. * opened with BDRV_O_UNMAP.
*/ */
BDRV_REQ_MAY_UNMAP = 0x4, BDRV_REQ_MAY_UNMAP = 0x4,
BDRV_REQ_NO_COPY_ON_READ = 0x8,
} BdrvRequestFlags; } BdrvRequestFlags;
typedef struct BlockSizes { typedef struct BlockSizes {
@ -252,6 +253,8 @@ int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, QEMUIOVector *qiov); int nb_sectors, QEMUIOVector *qiov);
int coroutine_fn bdrv_co_copy_on_readv(BlockDriverState *bs, int coroutine_fn bdrv_co_copy_on_readv(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
int coroutine_fn bdrv_co_no_copy_on_readv(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
int coroutine_fn bdrv_co_writev(BlockDriverState *bs, int64_t sector_num, int coroutine_fn bdrv_co_writev(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, QEMUIOVector *qiov); int nb_sectors, QEMUIOVector *qiov);
/* /*

1
trace-events
View File

@ -69,6 +69,7 @@ bdrv_aio_write_zeroes(void *bs, int64_t sector_num, int nb_sectors, int flags, v
bdrv_lock_medium(void *bs, bool locked) "bs %p locked %d" bdrv_lock_medium(void *bs, bool locked) "bs %p locked %d"
bdrv_co_readv(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d" bdrv_co_readv(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d"
bdrv_co_copy_on_readv(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d" bdrv_co_copy_on_readv(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d"
bdrv_co_no_copy_on_readv(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d"
bdrv_co_writev(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d" bdrv_co_writev(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d"
bdrv_co_write_zeroes(void *bs, int64_t sector_num, int nb_sector, int flags) "bs %p sector_num %"PRId64" nb_sectors %d flags %#x" bdrv_co_write_zeroes(void *bs, int64_t sector_num, int nb_sector, int flags) "bs %p sector_num %"PRId64" nb_sectors %d flags %#x"
bdrv_co_io_em(void *bs, int64_t sector_num, int nb_sectors, int is_write, void *acb) "bs %p sector_num %"PRId64" nb_sectors %d is_write %d acb %p" bdrv_co_io_em(void *bs, int64_t sector_num, int nb_sectors, int is_write, void *acb) "bs %p sector_num %"PRId64" nb_sectors %d is_write %d acb %p"