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authorDaniel P. Berrange <berrange@redhat.com>2016-02-10 18:41:05 +0000
committerPaolo Bonzini <pbonzini@redhat.com>2016-02-16 17:14:08 +0100
commitf72d705f0de9ec49248e72cf888624994f09eda2 (patch)
tree5ed3ba60b3faade70aa382bf73ad7956c145204e /nbd
parent1c778ef729dd50d4b06780af1f44b69c63c532f8 (diff)
downloadqemu-arm-f72d705f0de9ec49248e72cf888624994f09eda2.tar.gz
nbd: invert client logic for negotiating protocol version
The nbd_receive_negotiate() method takes different code paths based on whether 'name == NULL', and then checks the expected protocol version in each branch. This patch inverts the logic, so that it takes different code paths based on what protocol version it receives and then checks if name is NULL or not as needed. This facilitates later code which allows the client to be capable of using the new style protocol regardless of whether an export name is listed or not. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-Id: <1455129674-17255-8-git-send-email-berrange@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'nbd')
-rw-r--r--nbd/client.c60
1 files changed, 29 insertions, 31 deletions
diff --git a/nbd/client.c b/nbd/client.c
index f6dd0a398f..5064788bb1 100644
--- a/nbd/client.c
+++ b/nbd/client.c
@@ -116,20 +116,11 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint32_t *flags,
magic = be64_to_cpu(magic);
TRACE("Magic is 0x%" PRIx64, magic);
- if (name) {
+ if (magic == NBD_OPTS_MAGIC) {
uint32_t reserved = 0;
uint32_t opt;
uint32_t namesize;
- TRACE("Checking magic (opts_magic)");
- if (magic != NBD_OPTS_MAGIC) {
- if (magic == NBD_CLIENT_MAGIC) {
- error_setg(errp, "Server does not support export names");
- } else {
- error_setg(errp, "Bad magic received");
- }
- goto fail;
- }
if (read_sync(ioc, &tmp, sizeof(tmp)) != sizeof(tmp)) {
error_setg(errp, "Failed to read server flags");
goto fail;
@@ -142,6 +133,10 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint32_t *flags,
goto fail;
}
/* write the export name */
+ if (!name) {
+ error_setg(errp, "Server requires an export name");
+ goto fail;
+ }
magic = cpu_to_be64(magic);
if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
error_setg(errp, "Failed to send export name magic");
@@ -162,39 +157,42 @@ int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint32_t *flags,
error_setg(errp, "Failed to send export name");
goto fail;
}
- } else {
- TRACE("Checking magic (cli_magic)");
- if (magic != NBD_CLIENT_MAGIC) {
- if (magic == NBD_OPTS_MAGIC) {
- error_setg(errp, "Server requires an export name");
- } else {
- error_setg(errp, "Bad magic received");
- }
+ if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) {
+ error_setg(errp, "Failed to read export length");
goto fail;
}
- }
+ *size = be64_to_cpu(s);
+ TRACE("Size is %" PRIu64, *size);
- if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) {
- error_setg(errp, "Failed to read export length");
- goto fail;
- }
- *size = be64_to_cpu(s);
- TRACE("Size is %" PRIu64, *size);
+ if (read_sync(ioc, &tmp, sizeof(tmp)) != sizeof(tmp)) {
+ error_setg(errp, "Failed to read export flags");
+ goto fail;
+ }
+ *flags |= be16_to_cpu(tmp);
+ } else if (magic == NBD_CLIENT_MAGIC) {
+ if (name) {
+ error_setg(errp, "Server does not support export names");
+ goto fail;
+ }
+
+ if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) {
+ error_setg(errp, "Failed to read export length");
+ goto fail;
+ }
+ *size = be64_to_cpu(s);
+ TRACE("Size is %" PRIu64, *size);
- if (!name) {
if (read_sync(ioc, flags, sizeof(*flags)) != sizeof(*flags)) {
error_setg(errp, "Failed to read export flags");
goto fail;
}
*flags = be32_to_cpup(flags);
} else {
- if (read_sync(ioc, &tmp, sizeof(tmp)) != sizeof(tmp)) {
- error_setg(errp, "Failed to read export flags");
- goto fail;
- }
- *flags |= be16_to_cpu(tmp);
+ error_setg(errp, "Bad magic received");
+ goto fail;
}
+
if (read_sync(ioc, &buf, 124) != 124) {
error_setg(errp, "Failed to read reserved block");
goto fail;