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nbd/client: Pull out oldstyle size determination

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Another refactoring creating nbd_negotiate_finish_oldstyle()
for further reuse during 'qemu-nbd --list'.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Richard W.M. Jones <rjones@redhat.com>
Message-Id: <20190117193658.16413-16-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
This commit is contained in:
Eric Blake 2019-01-17 13:36:52 -06:00
parent 10b89988d6
commit b3c9d33bc4
1 changed files with 32 additions and 17 deletions
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49
nbd/client.c
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@ -814,7 +814,7 @@ static int nbd_negotiate_simple_meta_context(QIOChannel *ioc,
* Start the handshake to the server. After a positive return, the server
* is ready to accept additional NBD_OPT requests.
* Returns: negative errno: failure talking to server
* 0: server is oldstyle, client must still parse export size
* 0: server is oldstyle, must call nbd_negotiate_finish_oldstyle
* 1: server is newstyle, but can only accept EXPORT_NAME
* 2: server is newstyle, but lacks structured replies
* 3: server is newstyle and set up for structured replies
@ -920,6 +920,36 @@ static int nbd_start_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
}
}
/*
* nbd_negotiate_finish_oldstyle:
* Populate @info with the size and export flags from an oldstyle server,
* but does not consume 124 bytes of reserved zero padding.
* Returns 0 on success, -1 with @errp set on failure
*/
static int nbd_negotiate_finish_oldstyle(QIOChannel *ioc, NBDExportInfo *info,
Error **errp)
{
uint32_t oldflags;
if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) {
error_prepend(errp, "Failed to read export length: ");
return -EINVAL;
}
info->size = be64_to_cpu(info->size);
if (nbd_read(ioc, &oldflags, sizeof(oldflags), errp) < 0) {
error_prepend(errp, "Failed to read export flags: ");
return -EINVAL;
}
oldflags = be32_to_cpu(oldflags);
if (oldflags & ~0xffff) {
error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags);
return -EINVAL;
}
info->flags = oldflags;
return 0;
}
/*
* nbd_receive_negotiate:
* Connect to server, complete negotiation, and move into transmission phase.
@ -933,7 +963,6 @@ int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
int result;
bool zeroes;
bool base_allocation = info->base_allocation;
uint32_t oldflags;
assert(info->name);
trace_nbd_receive_negotiate_name(info->name);
@ -1006,23 +1035,9 @@ int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
error_setg(errp, "Server does not support non-empty export names");
return -EINVAL;
}
if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) {
error_prepend(errp, "Failed to read export length: ");
if (nbd_negotiate_finish_oldstyle(ioc, info, errp) < 0) {
return -EINVAL;
}
info->size = be64_to_cpu(info->size);
if (nbd_read(ioc, &oldflags, sizeof(oldflags), errp) < 0) {
error_prepend(errp, "Failed to read export flags: ");
return -EINVAL;
}
oldflags = be32_to_cpu(oldflags);
if (oldflags & ~0xffff) {
error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags);
return -EINVAL;
}
info->flags = oldflags;
break;
default:
return result;