qemu-kvm/SOURCES/kvm-nbd-server-add-nbd_meta_empty_or_pattern-helper.patch

164 lines
5.8 KiB
Diff

From de65ad93b1b0a38c8a3f26eb1bc4090eb19db00f Mon Sep 17 00:00:00 2001
From: John Snow <jsnow@redhat.com>
Date: Wed, 18 Jul 2018 22:55:02 +0200
Subject: [PATCH 244/268] nbd/server: add nbd_meta_empty_or_pattern helper
RH-Author: John Snow <jsnow@redhat.com>
Message-id: <20180718225511.14878-27-jsnow@redhat.com>
Patchwork-id: 81398
O-Subject: [RHEL-7.6 qemu-kvm-rhev PATCH 26/35] nbd/server: add nbd_meta_empty_or_pattern helper
Bugzilla: 1207657
RH-Acked-by: Eric Blake <eblake@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Fam Zheng <famz@redhat.com>
From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Add nbd_meta_pattern() and nbd_meta_empty_or_pattern() helpers for
metadata query parsing. nbd_meta_pattern() will be reused for the
"qemu" namespace in following patches.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20180609151758.17343-4-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: comment tweaks]
Signed-off-by: Eric Blake <eblake@redhat.com>
(cherry picked from commit b0769d8f8df0b51881f1f15c9e29722cf6191a43)
Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
nbd/server.c | 89 ++++++++++++++++++++++++++++++++++++++++++------------------
1 file changed, 62 insertions(+), 27 deletions(-)
diff --git a/nbd/server.c b/nbd/server.c
index 26cc41a..9171cd4 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -733,53 +733,87 @@ static int nbd_negotiate_send_meta_context(NBDClient *client,
return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0;
}
-/* nbd_meta_base_query
- *
- * Handle queries to 'base' namespace. For now, only the base:allocation
- * context is available. 'len' is the amount of text remaining to be read from
- * the current name, after the 'base:' portion has been stripped.
+/* Read strlen(@pattern) bytes, and set @match to true if they match @pattern.
+ * @match is never set to false.
*
* Return -errno on I/O error, 0 if option was completely handled by
* sending a reply about inconsistent lengths, or 1 on success.
*
- * Note: return code = 1 doesn't mean that we've parsed the "base:allocation"
- * namespace. It only means that there are no errors.
+ * Note: return code = 1 doesn't mean that we've read exactly @pattern.
+ * It only means that there are no errors.
*/
-static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta,
- uint32_t len, Error **errp)
+static int nbd_meta_pattern(NBDClient *client, const char *pattern, bool *match,
+ Error **errp)
{
int ret;
- char query[sizeof("allocation") - 1];
- size_t alen = strlen("allocation");
-
- if (len == 0) {
- if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
- meta->base_allocation = true;
- }
- trace_nbd_negotiate_meta_query_parse("base:");
- return 1;
- }
+ char *query;
+ size_t len = strlen(pattern);
- if (len != alen) {
- trace_nbd_negotiate_meta_query_skip("not base:allocation");
- return nbd_opt_skip(client, len, errp);
- }
+ assert(len);
+ query = g_malloc(len);
ret = nbd_opt_read(client, query, len, errp);
if (ret <= 0) {
+ g_free(query);
return ret;
}
- if (strncmp(query, "allocation", alen) == 0) {
- trace_nbd_negotiate_meta_query_parse("base:allocation");
- meta->base_allocation = true;
+ if (strncmp(query, pattern, len) == 0) {
+ trace_nbd_negotiate_meta_query_parse(pattern);
+ *match = true;
} else {
- trace_nbd_negotiate_meta_query_skip("not base:allocation");
+ trace_nbd_negotiate_meta_query_skip("pattern not matched");
}
+ g_free(query);
return 1;
}
+/*
+ * Read @len bytes, and set @match to true if they match @pattern, or if @len
+ * is 0 and the client is performing _LIST_. @match is never set to false.
+ *
+ * Return -errno on I/O error, 0 if option was completely handled by
+ * sending a reply about inconsistent lengths, or 1 on success.
+ *
+ * Note: return code = 1 doesn't mean that we've read exactly @pattern.
+ * It only means that there are no errors.
+ */
+static int nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern,
+ uint32_t len, bool *match, Error **errp)
+{
+ if (len == 0) {
+ if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
+ *match = true;
+ }
+ trace_nbd_negotiate_meta_query_parse("empty");
+ return 1;
+ }
+
+ if (len != strlen(pattern)) {
+ trace_nbd_negotiate_meta_query_skip("different lengths");
+ return nbd_opt_skip(client, len, errp);
+ }
+
+ return nbd_meta_pattern(client, pattern, match, errp);
+}
+
+/* nbd_meta_base_query
+ *
+ * Handle queries to 'base' namespace. For now, only the base:allocation
+ * context is available. 'len' is the amount of text remaining to be read from
+ * the current name, after the 'base:' portion has been stripped.
+ *
+ * Return -errno on I/O error, 0 if option was completely handled by
+ * sending a reply about inconsistent lengths, or 1 on success.
+ */
+static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta,
+ uint32_t len, Error **errp)
+{
+ return nbd_meta_empty_or_pattern(client, "allocation", len,
+ &meta->base_allocation, errp);
+}
+
/* nbd_negotiate_meta_query
*
* Parse namespace name and call corresponding function to parse body of the
@@ -823,6 +857,7 @@ static int nbd_negotiate_meta_query(NBDClient *client,
return nbd_opt_skip(client, len, errp);
}
+ trace_nbd_negotiate_meta_query_parse("base:");
return nbd_meta_base_query(client, meta, len, errp);
}
--
1.8.3.1