diff options
| author | Wen Congyang <wency@cn.fujitsu.com> | 2015-09-08 11:28:32 +0800 |
|---|---|---|
| committer | Jeff Cody <jcody@redhat.com> | 2015-09-25 08:37:07 -0400 |
| commit | 9568b511c9f91c3d21ea3e83426d4ee7168c98bb (patch) | |
| tree | db4332c4539db54b69b314a47a7eb4c921ca7104 | |
| parent | 4da65c80921139f3e0ff63f5ea20c5d9c778364f (diff) | |
block: Introduce a new API bdrv_co_no_copy_on_readv()
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>
| -rw-r--r-- | block/io.c | 12 | ||||
| -rw-r--r-- | include/block/block.h | 9 | ||||
| -rw-r--r-- | trace-events | 1 |
3 files changed, 18 insertions, 4 deletions
diff --git a/block/io.c b/block/io.c index d4bc83b33b..94e18e6a9d 100644 --- a/block/io.c +++ b/block/io.c @@ -932,7 +932,8 @@ static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs, 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; } @@ -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); } +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, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) { diff --git a/include/block/block.h b/include/block/block.h index ef67353108..2dd66300ed 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -51,15 +51,16 @@ typedef struct BlockFragInfo { } BlockFragInfo; typedef enum { - BDRV_REQ_COPY_ON_READ = 0x1, - BDRV_REQ_ZERO_WRITE = 0x2, + BDRV_REQ_COPY_ON_READ = 0x1, + BDRV_REQ_ZERO_WRITE = 0x2, /* 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) * 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 * opened with BDRV_O_UNMAP. */ - BDRV_REQ_MAY_UNMAP = 0x4, + BDRV_REQ_MAY_UNMAP = 0x4, + BDRV_REQ_NO_COPY_ON_READ = 0x8, } BdrvRequestFlags; 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 coroutine_fn bdrv_co_copy_on_readv(BlockDriverState *bs, 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 nb_sectors, QEMUIOVector *qiov); /* diff --git a/trace-events b/trace-events index 25c53e0c7c..a70ea9c3ae 100644 --- a/trace-events +++ b/trace-events @@ -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_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_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_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" |