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authorSrinivas Eeda <srinivas.eeda@oracle.com>2007-01-29 15:31:35 -0800
committerMark Fasheh <mark.fasheh@oracle.com>2007-02-07 12:09:14 -0800
commit1faf289454b9eeb6e463da3eee47f7009668370d (patch)
treefe77643771a985a20c3782fb2a952cf9c05937a5 /fs/ocfs2/dlm/dlmdomain.c
parentocfs2_dlm: Ensure correct ordering of set/clear refmap bit on lockres (diff)
downloadlinux-dev-1faf289454b9eeb6e463da3eee47f7009668370d.tar.xz
linux-dev-1faf289454b9eeb6e463da3eee47f7009668370d.zip
ocfs2_dlm: disallow a domain join if node maps mismatch
There is a small window where a joining node may not see the node(s) that just died but are still part of the domain. To fix this, we must disallow join requests if the joining node has a different node map. A new field node_map is added to dlm_query_join_request to send the current nodes nodemap along with join request. On the receiving end the nodes that are part of the cluster verifies if this new node sees all the nodes that are still part of the cluster. They disallow the join if the maps mismatch. Signed-off-by: Srinivas Eeda <srinivas.eeda@oracle.com> Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Diffstat (limited to '')
-rw-r--r--fs/ocfs2/dlm/dlmdomain.c54
1 files changed, 54 insertions, 0 deletions
diff --git a/fs/ocfs2/dlm/dlmdomain.c b/fs/ocfs2/dlm/dlmdomain.c
index 6590e1bca23c..19b57a6bcb1a 100644
--- a/fs/ocfs2/dlm/dlmdomain.c
+++ b/fs/ocfs2/dlm/dlmdomain.c
@@ -48,6 +48,36 @@
#define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_DOMAIN)
#include "cluster/masklog.h"
+/*
+ * ocfs2 node maps are array of long int, which limits to send them freely
+ * across the wire due to endianness issues. To workaround this, we convert
+ * long ints to byte arrays. Following 3 routines are helper functions to
+ * set/test/copy bits within those array of bytes
+ */
+static inline void byte_set_bit(u8 nr, u8 map[])
+{
+ map[nr >> 3] |= (1UL << (nr & 7));
+}
+
+static inline int byte_test_bit(u8 nr, u8 map[])
+{
+ return ((1UL << (nr & 7)) & (map[nr >> 3])) != 0;
+}
+
+static inline void byte_copymap(u8 dmap[], unsigned long smap[],
+ unsigned int sz)
+{
+ unsigned int nn;
+
+ if (!sz)
+ return;
+
+ memset(dmap, 0, ((sz + 7) >> 3));
+ for (nn = 0 ; nn < sz; nn++)
+ if (test_bit(nn, smap))
+ byte_set_bit(nn, dmap);
+}
+
static void dlm_free_pagevec(void **vec, int pages)
{
while (pages--)
@@ -641,6 +671,7 @@ static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
struct dlm_query_join_request *query;
enum dlm_query_join_response response;
struct dlm_ctxt *dlm = NULL;
+ u8 nodenum;
query = (struct dlm_query_join_request *) msg->buf;
@@ -664,6 +695,25 @@ static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
spin_lock(&dlm_domain_lock);
dlm = __dlm_lookup_domain_full(query->domain, query->name_len);
+ if (!dlm)
+ goto unlock_respond;
+
+ /*
+ * There is a small window where the joining node may not see the
+ * node(s) that just left but still part of the cluster. DISALLOW
+ * join request if joining node has different node map.
+ */
+ nodenum=0;
+ while (nodenum < O2NM_MAX_NODES) {
+ if (test_bit(nodenum, dlm->domain_map)) {
+ if (!byte_test_bit(nodenum, query->node_map)) {
+ response = JOIN_DISALLOW;
+ goto unlock_respond;
+ }
+ }
+ nodenum++;
+ }
+
/* Once the dlm ctxt is marked as leaving then we don't want
* to be put in someone's domain map.
* Also, explicitly disallow joining at certain troublesome
@@ -705,6 +755,7 @@ static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
spin_unlock(&dlm->spinlock);
}
+unlock_respond:
spin_unlock(&dlm_domain_lock);
respond:
@@ -854,6 +905,9 @@ static int dlm_request_join(struct dlm_ctxt *dlm,
join_msg.name_len = strlen(dlm->name);
memcpy(join_msg.domain, dlm->name, join_msg.name_len);
+ /* copy live node map to join message */
+ byte_copymap(join_msg.node_map, dlm->live_nodes_map, O2NM_MAX_NODES);
+
status = o2net_send_message(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY, &join_msg,
sizeof(join_msg), node, &retval);
if (status < 0 && status != -ENOPROTOOPT) {