| Message ID | 1602524605-481160-8-git-send-email-andrey.shinkevich@virtuozzo.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Apply COR-filter to the block-stream permanently | expand |
On 12.10.20 19:43, Andrey Shinkevich wrote: > Add the new member supported_read_flags to BlockDriverState structure. > It will control the BDRV_REQ_PREFETCH flag set for copy-on-read > operations. > > Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> > --- > include/block/block_int.h | 4 ++++ > 1 file changed, 4 insertions(+) Not sure what the problem with passing BDRV_REQ_PREFETCH to drivers that aren’t the COR filter are would be, but: Reviewed-by: Max Reitz <mreitz@redhat.com> (I mean, outside of the context of COR the flag is undefined, so it can be anything, but intuitively I’d assume it means “no need to read the data to memory” then, too. So if a driver doesn’t support it, nothing bad should happen. Hm. Well, unless the driver passes the flag on (unsuspectingly) and a metadata-bearing child doesn’t return any data that the drviver needs. Yeah, better to explicitly disallow the flag for all unsupporting drivers then.)
diff --git a/include/block/block_int.h b/include/block/block_int.h index f782737..a142867 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -873,6 +873,10 @@ struct BlockDriverState { /* I/O Limits */ BlockLimits bl; + /* + * Flags honored during pread (so far: BDRV_REQ_PREFETCH) + */ + unsigned int supported_read_flags; /* Flags honored during pwrite (so far: BDRV_REQ_FUA, * BDRV_REQ_WRITE_UNCHANGED). * If a driver does not support BDRV_REQ_WRITE_UNCHANGED, those
Add the new member supported_read_flags to BlockDriverState structure. It will control the BDRV_REQ_PREFETCH flag set for copy-on-read operations. Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> --- include/block/block_int.h | 4 ++++ 1 file changed, 4 insertions(+)