On 8/30/19 1:07 PM, Vladimir Sementsov-Ogievskiy wrote: > 23.08.2019 17:37, Eric Blake wrote: >> Commit fe0480d6 and friends added BDRV_REQ_NO_FALLBACK as a way to >> avoid wasting time on a preliminary write-zero request that will later >> be rewritten by actual data, if it is known that the write-zero >> request will use a slow fallback; but in doing so, could not optimize >> for NBD. The NBD specification is now considering an extension that >> will allow passing on those semantics; this patch updates the new >> protocol bits and 'qemu-nbd --list' output to recognize the bit, as >> well as the new errno value possible when using the new flag; while >> upcoming patches will improve the client to use the feature when >> present, and the server to advertise support for it. >>
>> +++ b/nbd/server.c >> @@ -55,6 +55,8 @@ static int system_errno_to_nbd_errno(int err) >> return NBD_ENOSPC; >> case EOVERFLOW: >> return NBD_EOVERFLOW; >> + case ENOTSUP: >> + return NBD_ENOTSUP; > I'm squashing this in: diff --git i/nbd/server.c w/nbd/server.c index b3bd08ef2953..4992148de1c4 100644 --- i/nbd/server.c +++ w/nbd/server.c @@ -56,6 +56,9 @@ static int system_errno_to_nbd_errno(int err) case EOVERFLOW: return NBD_EOVERFLOW; case ENOTSUP: +#if ENOTSUP != EOPNOTSUPP + case EOPNOTSUPP: +#endif return NBD_ENOTSUP; case ESHUTDOWN: return NBD_ESHUTDOWN; It makes no difference on Linux, but may matter on other platforms (since POSIX says the two may be equivalent, but may also be distinct). > -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org
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