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block: Don't wait serialising for non-COR read requests

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The assertion problem was noticed in 06c3916b35, but it wasn't
completely fixed, because even though the req is not marked as
serialising, it still gets serialised by wait_serialising_requests
against other serialising requests, which could lead to the same
assertion failure.

Fix it by even more explicitly skipping the serialising for this
specific case.

Signed-off-by: Fam Zheng <famz@redhat.com>
Message-id: 1448962590-2842-2-git-send-email-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Fam Zheng 2015-12-01 17:36:28 +08:00 committed by Stefan Hajnoczi
parent d21e8776f6
commit 61408b250e
4 changed files with 11 additions and 9 deletions
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2
block/backup.c
View File

@ -132,7 +132,7 @@ static int coroutine_fn backup_do_cow(BlockDriverState *bs,
qemu_iovec_init_external(&bounce_qiov, &iov, 1);
if (is_write_notifier) {
ret = bdrv_co_no_copy_on_readv(bs,
ret = bdrv_co_readv_no_serialising(bs,
start * BACKUP_SECTORS_PER_CLUSTER,
n, &bounce_qiov);
} else {

10
block/io.c
View File

@ -863,7 +863,9 @@ static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs,
mark_request_serialising(req, bdrv_get_cluster_size(bs));
}
if (!(flags & BDRV_REQ_NO_SERIALISING)) {
wait_serialising_requests(req);
}
if (flags & BDRV_REQ_COPY_ON_READ) {
int pnum;
@ -952,7 +954,7 @@ static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs,
}
/* 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)) {
if (bs->copy_on_read && !(flags & BDRV_REQ_NO_SERIALISING)) {
flags |= BDRV_REQ_COPY_ON_READ;
}
@ -1021,13 +1023,13 @@ 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,
int coroutine_fn bdrv_co_readv_no_serialising(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
{
trace_bdrv_co_no_copy_on_readv(bs, sector_num, nb_sectors);
trace_bdrv_co_readv_no_serialising(bs, sector_num, nb_sectors);
return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov,
BDRV_REQ_NO_COPY_ON_READ);
BDRV_REQ_NO_SERIALISING);
}
int coroutine_fn bdrv_co_copy_on_readv(BlockDriverState *bs,

4
include/block/block.h
View File

@ -61,7 +61,7 @@ typedef enum {
* opened with BDRV_O_UNMAP.
*/
BDRV_REQ_MAY_UNMAP = 0x4,
BDRV_REQ_NO_COPY_ON_READ = 0x8,
BDRV_REQ_NO_SERIALISING = 0x8,
} BdrvRequestFlags;
typedef struct BlockSizes {
@ -248,7 +248,7 @@ 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,
int coroutine_fn bdrv_co_readv_no_serialising(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);

2
trace-events
View File

@ -69,7 +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_readv_no_serialising(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"