Re: [Qemu-block] [PATCH v4 03/11] block: allow serialized reads to intersect
06.11.2018 20:57, Kevin Wolf wrote: > Am 15.10.2018 um 18:06 hat Vladimir Sementsov-Ogievskiy geschrieben: >> Otherwise, if we have serialized read-part in copy_range from backing >> file to its parent if CoW take place, this CoW's sub-reads will >> intersect with firstly created serialized read request. >> >> Anyway, reads should not influence on disk view, let's allow them to >> intersect. >> >> Signed-off-by: Vladimir Sementsov-Ogievskiy > What about reads that internally trigger writes, such as copy-on-read? oops :). yes, I've to rethink this thing. > > Kevin -- Best regards, Vladimir
Re: [Qemu-block] [PATCH v4 03/11] block: allow serialized reads to intersect
Am 15.10.2018 um 18:06 hat Vladimir Sementsov-Ogievskiy geschrieben: > Otherwise, if we have serialized read-part in copy_range from backing > file to its parent if CoW take place, this CoW's sub-reads will > intersect with firstly created serialized read request. > > Anyway, reads should not influence on disk view, let's allow them to > intersect. > > Signed-off-by: Vladimir Sementsov-Ogievskiy What about reads that internally trigger writes, such as copy-on-read? Kevin
[Qemu-block] [PATCH v4 03/11] block: allow serialized reads to intersect
Otherwise, if we have serialized read-part in copy_range from backing
file to its parent if CoW take place, this CoW's sub-reads will
intersect with firstly created serialized read request.
Anyway, reads should not influence on disk view, let's allow them to
intersect.
Signed-off-by: Vladimir Sementsov-Ogievskiy
---
block/io.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/block/io.c b/block/io.c
index bd9d688f8b..d4e46cb3dc 100644
--- a/block/io.c
+++ b/block/io.c
@@ -735,7 +735,8 @@ static bool coroutine_fn
wait_serialising_requests(BdrvTrackedRequest *self)
retry = false;
qemu_co_mutex_lock(>reqs_lock);
QLIST_FOREACH(req, >tracked_requests, list) {
-if (req == self || (!req->serialising && !self->serialising)) {
+if (req == self || (!req->serialising && !self->serialising) ||
+(self->type == BDRV_TRACKED_READ && req->type == self->type)) {
continue;
}
if (tracked_request_overlaps(req, self->overlap_offset,
--
2.18.0
