[Ocfs2-devel] ocfs2: Negotiate locking protocol versions.
Joel Becker
Joel.Becker at oracle.com
Thu Jan 24 19:17:30 PST 2008
Currently, ocfs2 communication has exactly one level of compatibility. When
nodes connect via TCP, they advertise their compatibility level. If the
versions do not match, two nodes cannot speak to each other and they
disconnect.
This provides no forward or backwards compatibility. When the network
protocol changes, all nodes must unmount all ocfs2 filesystems and reload
the new ocfs2 module. It's a flag-day event.
Even worse, this protocol value covers a host of changes. The actual
network packets haven't changed in forever. The o2dlm messages haven't
either. What has changed are behaviors. From the o2dlm perspective,
perhaps some processing has changed order. For the ocfs2 filesystem,
perhaps a new cluster lock has been added. Whatever the change, the
network compatibility is changed and everyone must unmount and reload.
We are introducing negotiation of compatibility at a finer grain.
First, we bump the network protocol version. This breaks compatiblity
with older versions that do not know how to negotiate compatibility. With
any luck, this number won't have to change in the future.
Next, we introduce a major/minor version number scheme for entities that
communicate. Specifically, o2dlm has a major/minor version for interaction
with o2dlm on other nodes, and ocfs2 itself has a major/minor version for
interacting with the filesystem on other nodes.
What's the difference? If ocfs2 adds a new lock type to inodes, it needs
every node to know about the lock type before it can use it. So the
filesystem version is changed. The scheme allows the driver to determine
whether to run in the old mode without the new lock type or in the new mode
with the lock type. However, no o2dlm messages or behavior has changed, so
the o2dlm version does not have to be modified. This separates changes to
o2dlm from changes to ocfs2.
How do we negotiate compatibility?
- If the node is the only mounter, the version is set to the node's
(major, minor).
- If the joining node has a different major than the other mounted
nodes, it is rejected (JOIN_PROTOCOL_MISMATCH). Major numbers are a
flag-day change. This allows the scheme to perform flag days when
they are necessary.
- If the joining node has the same major, but its minor is smaller than
that negotiated by the other nodes, it is rejected. This is because
the already mounted nodes are running with features the joining node
does not support. Thus, it cannot safely interact.
- If the joining node has the same major and minor as other nodes, it
proceeds with that (major, minor) locking version.
- If thea joining node has the same major but a larger minor than
negotiated by the other nodes, the new node will proceed with
the minor number as negotiated, disabling any behavior not supported
by the negotiated minor version.
This negotiation happens for both the o2dlm and ocfs2 compatibility
values.
As the first message between nodes is the domain join, we handle the
negotiation there. The join request sends both the o2dlm and ocfs2
compatibility values. Existing nodes will validate them and respond
accordingly. Once ocfs2 has joined a specific domain, it will have
the compatibility information it needs to run.
Signed-off-by: Joel Becker <joel.becker at oracle.com>
---
fs/ocfs2/cluster/tcp_internal.h | 11 ++-
fs/ocfs2/dlm/dlmapi.h | 7 ++-
fs/ocfs2/dlm/dlmcommon.h | 24 +++++-
fs/ocfs2/dlm/dlmdomain.c | 183 +++++++++++++++++++++++++++++++++------
fs/ocfs2/dlm/dlmfs.c | 13 +++-
fs/ocfs2/dlm/userdlm.c | 5 +-
fs/ocfs2/dlm/userdlm.h | 3 +-
fs/ocfs2/dlmglue.c | 29 ++++++-
fs/ocfs2/ocfs2.h | 1 +
9 files changed, 242 insertions(+), 34 deletions(-)
diff --git a/fs/ocfs2/cluster/tcp_internal.h b/fs/ocfs2/cluster/tcp_internal.h
index b2e832a..d25b9af 100644
--- a/fs/ocfs2/cluster/tcp_internal.h
+++ b/fs/ocfs2/cluster/tcp_internal.h
@@ -38,6 +38,15 @@
* locking semantics of the file system using the protocol. It should
* be somewhere else, I'm sure, but right now it isn't.
*
+ * With version 11, we separate out the filesystem locking portion. The
+ * filesystem now has a major.minor version it negotiates. Version 11
+ * introduces this negotiation to the o2dlm protocol, and as such the
+ * version here in tcp_internal.h should not need to be bumped for
+ * filesystem locking changes.
+ *
+ * New in version 11
+ * - Negotiation of filesystem locking in the dlm join.
+ *
* New in version 10:
* - Meta/data locks combined
*
@@ -66,7 +75,7 @@
* - full 64 bit i_size in the metadata lock lvbs
* - introduction of "rw" lock and pushing meta/data locking down
*/
-#define O2NET_PROTOCOL_VERSION 10ULL
+#define O2NET_PROTOCOL_VERSION 11ULL
struct o2net_handshake {
__be64 protocol_version;
__be64 connector_id;
diff --git a/fs/ocfs2/dlm/dlmapi.h b/fs/ocfs2/dlm/dlmapi.h
index cfd5cb6..b5786a7 100644
--- a/fs/ocfs2/dlm/dlmapi.h
+++ b/fs/ocfs2/dlm/dlmapi.h
@@ -193,7 +193,12 @@ enum dlm_status dlmunlock(struct dlm_ctxt *dlm,
dlm_astunlockfunc_t *unlockast,
void *data);
-struct dlm_ctxt * dlm_register_domain(const char *domain, u32 key);
+struct dlm_protocol_version {
+ u8 pv_major;
+ u8 pv_minor;
+};
+struct dlm_ctxt * dlm_register_domain(const char *domain, u32 key,
+ struct dlm_protocol_version *fs_proto);
void dlm_unregister_domain(struct dlm_ctxt *dlm);
diff --git a/fs/ocfs2/dlm/dlmcommon.h b/fs/ocfs2/dlm/dlmcommon.h
index e90b92f..5e10d42 100644
--- a/fs/ocfs2/dlm/dlmcommon.h
+++ b/fs/ocfs2/dlm/dlmcommon.h
@@ -142,6 +142,12 @@ struct dlm_ctxt
spinlock_t work_lock;
struct list_head dlm_domain_handlers;
struct list_head dlm_eviction_callbacks;
+
+ /* The filesystem specifies this at domain registration. We
+ * cache it here to know what to tell other nodes. */
+ struct dlm_protocol_version fs_locking_proto;
+ /* This is the inter-dlm communication version */
+ struct dlm_protocol_version dlm_locking_proto;
};
static inline struct hlist_head *dlm_lockres_hash(struct dlm_ctxt *dlm, unsigned i)
@@ -589,10 +595,24 @@ struct dlm_proxy_ast
#define DLM_PROXY_AST_MAX_LEN (sizeof(struct dlm_proxy_ast)+DLM_LVB_LEN)
#define DLM_MOD_KEY (0x666c6172)
-enum dlm_query_join_response {
+enum dlm_query_join_response_code {
JOIN_DISALLOW = 0,
JOIN_OK,
JOIN_OK_NO_MAP,
+ JOIN_PROTOCOL_MISMATCH,
+};
+
+union dlm_query_join_response {
+ int intval;
+ struct {
+ u8 code; /* Response code. dlm_minor and fs_minor
+ are only valid if this is JOIN_OK */
+ u8 dlm_minor; /* The minor version of the protocol the
+ dlm is speaking. */
+ u8 fs_minor; /* The minor version of the protocol the
+ filesystem is speaking. */
+ u8 reserved;
+ } packet;
};
struct dlm_lock_request
@@ -633,6 +653,8 @@ struct dlm_query_join_request
u8 node_idx;
u8 pad1[2];
u8 name_len;
+ struct dlm_protocol_version dlm_proto;
+ struct dlm_protocol_version fs_proto;
u8 domain[O2NM_MAX_NAME_LEN];
u8 node_map[BITS_TO_BYTES(O2NM_MAX_NODES)];
};
diff --git a/fs/ocfs2/dlm/dlmdomain.c b/fs/ocfs2/dlm/dlmdomain.c
index 6954565..0ff2e5a 100644
--- a/fs/ocfs2/dlm/dlmdomain.c
+++ b/fs/ocfs2/dlm/dlmdomain.c
@@ -123,6 +123,17 @@ DEFINE_SPINLOCK(dlm_domain_lock);
LIST_HEAD(dlm_domains);
static DECLARE_WAIT_QUEUE_HEAD(dlm_domain_events);
+/*
+ * The supported protocol version for DLM communication. Running domains
+ * will have a negotiated version with the same major number and a minor
+ * number equal or smaller. The dlm_ctxt->dlm_locking_proto field should
+ * be used to determine what a running domain is actually using.
+ */
+static const struct dlm_protocol_version dlm_protocol = {
+ .pv_major = 1,
+ .pv_minor = 0,
+};
+
#define DLM_DOMAIN_BACKOFF_MS 200
static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
@@ -133,6 +144,8 @@ static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data,
void **ret_data);
static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data,
void **ret_data);
+static int dlm_protocol_compare(struct dlm_protocol_version *existing,
+ struct dlm_protocol_version *request);
static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm);
@@ -668,11 +681,41 @@ void dlm_unregister_domain(struct dlm_ctxt *dlm)
}
EXPORT_SYMBOL_GPL(dlm_unregister_domain);
+static int dlm_query_join_proto_check(char *proto_type, int node,
+ struct dlm_protocol_version *ours,
+ struct dlm_protocol_version *request)
+{
+ int rc;
+ struct dlm_protocol_version proto = *request;
+
+ if (!dlm_protocol_compare(ours, &proto)) {
+ mlog(0, "node %u wanted to join with %s locking protocol %u.%u, we respond with %u.%u\n",
+ node, proto_type,
+ request->pv_major,
+ request->pv_minor,
+ proto.pv_major, proto.pv_minor);
+ request->pv_minor = proto.pv_minor;
+ rc = 0;
+ } else {
+ mlog(ML_NOTICE, "Node %u wanted to join with %s locking protocol %u.%u, but we have %u.%u, disallowing\n",
+ node, proto_type,
+ request->pv_major,
+ request->pv_minor,
+ ours->pv_major,
+ ours->pv_minor);
+ rc = 1;
+ }
+
+ return rc;
+}
+
static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
void **ret_data)
{
struct dlm_query_join_request *query;
- enum dlm_query_join_response response;
+ union dlm_query_join_response response = {
+ .packet.code = JOIN_DISALLOW,
+ };
struct dlm_ctxt *dlm = NULL;
u8 nodenum;
@@ -690,11 +733,11 @@ static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
mlog(0, "node %u is not in our live map yet\n",
query->node_idx);
- response = JOIN_DISALLOW;
+ response.packet.code = JOIN_DISALLOW;
goto respond;
}
- response = JOIN_OK_NO_MAP;
+ response.packet.code = JOIN_OK_NO_MAP;
spin_lock(&dlm_domain_lock);
dlm = __dlm_lookup_domain_full(query->domain, query->name_len);
@@ -713,7 +756,7 @@ static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
mlog(0, "disallow join as node %u does not "
"have node %u in its nodemap\n",
query->node_idx, nodenum);
- response = JOIN_DISALLOW;
+ response.packet.code = JOIN_DISALLOW;
goto unlock_respond;
}
}
@@ -733,30 +776,48 @@ static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
/*If this is a brand new context and we
* haven't started our join process yet, then
* the other node won the race. */
- response = JOIN_OK_NO_MAP;
+ response.packet.code = JOIN_OK_NO_MAP;
} else if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
/* Disallow parallel joins. */
- response = JOIN_DISALLOW;
+ response.packet.code = JOIN_DISALLOW;
} else if (dlm->reco.state & DLM_RECO_STATE_ACTIVE) {
mlog(0, "node %u trying to join, but recovery "
"is ongoing.\n", bit);
- response = JOIN_DISALLOW;
+ response.packet.code = JOIN_DISALLOW;
} else if (test_bit(bit, dlm->recovery_map)) {
mlog(0, "node %u trying to join, but it "
"still needs recovery.\n", bit);
- response = JOIN_DISALLOW;
+ response.packet.code = JOIN_DISALLOW;
} else if (test_bit(bit, dlm->domain_map)) {
mlog(0, "node %u trying to join, but it "
"is still in the domain! needs recovery?\n",
bit);
- response = JOIN_DISALLOW;
+ response.packet.code = JOIN_DISALLOW;
} else {
/* Alright we're fully a part of this domain
* so we keep some state as to who's joining
* and indicate to him that needs to be fixed
* up. */
- response = JOIN_OK;
- __dlm_set_joining_node(dlm, query->node_idx);
+
+ /* Make sure we speak compatible locking protocols. */
+ if (dlm_query_join_proto_check("DLM", bit,
+ &dlm->dlm_locking_proto,
+ &query->dlm_proto)) {
+ response.packet.code =
+ JOIN_PROTOCOL_MISMATCH;
+ } else if (dlm_query_join_proto_check("fs", bit,
+ &dlm->fs_locking_proto,
+ &query->fs_proto)) {
+ response.packet.code =
+ JOIN_PROTOCOL_MISMATCH;
+ } else {
+ response.packet.dlm_minor =
+ query->dlm_proto.pv_minor;
+ response.packet.fs_minor =
+ query->fs_proto.pv_minor;
+ response.packet.code = JOIN_OK;
+ __dlm_set_joining_node(dlm, query->node_idx);
+ }
}
spin_unlock(&dlm->spinlock);
@@ -765,9 +826,9 @@ unlock_respond:
spin_unlock(&dlm_domain_lock);
respond:
- mlog(0, "We respond with %u\n", response);
+ mlog(0, "We respond with %u\n", response.packet.code);
- return response;
+ return response.intval;
}
static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data,
@@ -899,10 +960,11 @@ static int dlm_send_join_cancels(struct dlm_ctxt *dlm,
static int dlm_request_join(struct dlm_ctxt *dlm,
int node,
- enum dlm_query_join_response *response)
+ enum dlm_query_join_response_code *response)
{
- int status, retval;
+ int status;
struct dlm_query_join_request join_msg;
+ union dlm_query_join_response join_resp;
mlog(0, "querying node %d\n", node);
@@ -910,12 +972,15 @@ static int dlm_request_join(struct dlm_ctxt *dlm,
join_msg.node_idx = dlm->node_num;
join_msg.name_len = strlen(dlm->name);
memcpy(join_msg.domain, dlm->name, join_msg.name_len);
+ join_msg.dlm_proto = dlm->dlm_locking_proto;
+ join_msg.fs_proto = dlm->fs_locking_proto;
/* 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);
+ sizeof(join_msg), node,
+ &join_resp.intval);
if (status < 0 && status != -ENOPROTOOPT) {
mlog_errno(status);
goto bail;
@@ -928,14 +993,36 @@ static int dlm_request_join(struct dlm_ctxt *dlm,
if (status == -ENOPROTOOPT) {
status = 0;
*response = JOIN_OK_NO_MAP;
- } else if (retval == JOIN_DISALLOW ||
- retval == JOIN_OK ||
- retval == JOIN_OK_NO_MAP) {
- *response = retval;
+ } else if (join_resp.packet.code == JOIN_DISALLOW ||
+ join_resp.packet.code == JOIN_OK_NO_MAP) {
+ *response = join_resp.packet.code;
+ } else if (join_resp.packet.code == JOIN_PROTOCOL_MISMATCH) {
+ mlog(ML_NOTICE, "This node requested DLM locking protocol %u.%u and filesystem locking protocol %u.%u. At least one of the protocol versions on node %d is not compatible, disconnecting\n",
+ dlm->dlm_locking_proto.pv_major,
+ dlm->dlm_locking_proto.pv_minor,
+ dlm->fs_locking_proto.pv_major,
+ dlm->fs_locking_proto.pv_minor,
+ node);
+ status = -EPROTO;
+ *response = join_resp.packet.code;
+ } else if (join_resp.packet.code == JOIN_OK) {
+ *response = join_resp.packet.code;
+ /* Use the same locking protocol as the remote node */
+ dlm->dlm_locking_proto.pv_minor =
+ join_resp.packet.dlm_minor;
+ dlm->fs_locking_proto.pv_minor =
+ join_resp.packet.fs_minor;
+ mlog(0,
+ "Node %d responds JOIN_OK with DLM locking protocol %u.%u and fs locking protocol %u.%u\n",
+ node,
+ dlm->dlm_locking_proto.pv_major,
+ dlm->dlm_locking_proto.pv_minor,
+ dlm->fs_locking_proto.pv_major,
+ dlm->fs_locking_proto.pv_minor);
} else {
status = -EINVAL;
- mlog(ML_ERROR, "invalid response %d from node %u\n", retval,
- node);
+ mlog(ML_ERROR, "invalid response %d from node %u\n",
+ join_resp.packet.code, node);
}
mlog(0, "status %d, node %d response is %d\n", status, node,
@@ -1008,7 +1095,7 @@ struct domain_join_ctxt {
static int dlm_should_restart_join(struct dlm_ctxt *dlm,
struct domain_join_ctxt *ctxt,
- enum dlm_query_join_response response)
+ enum dlm_query_join_response_code response)
{
int ret;
@@ -1034,7 +1121,7 @@ static int dlm_try_to_join_domain(struct dlm_ctxt *dlm)
{
int status = 0, tmpstat, node;
struct domain_join_ctxt *ctxt;
- enum dlm_query_join_response response = JOIN_DISALLOW;
+ enum dlm_query_join_response_code response = JOIN_DISALLOW;
mlog_entry("%p", dlm);
@@ -1450,10 +1537,38 @@ leave:
}
/*
- * dlm_register_domain: one-time setup per "domain"
+ * Compare a requested locking protocol version against the current one.
+ *
+ * If the major numbers are different, they are incompatible.
+ * If the current minor is greater than the request, they are incompatible.
+ * If the current minor is less than or equal to the request, they are
+ * compatible, and the requester should run at the current minor version.
+ */
+static int dlm_protocol_compare(struct dlm_protocol_version *existing,
+ struct dlm_protocol_version *request)
+{
+ if (existing->pv_major != request->pv_major)
+ return 1;
+
+ if (existing->pv_minor > request->pv_minor)
+ return 1;
+
+ if (existing->pv_minor < request->pv_minor)
+ request->pv_minor = existing->pv_minor;
+
+ return 0;
+}
+
+/*
+ * dlm_register_domain: one-time setup per "domain".
+ *
+ * The filesystem passes in the requested locking version via proto.
+ * If registration was successful, proto will contain the negotiated
+ * locking protocol.
*/
struct dlm_ctxt * dlm_register_domain(const char *domain,
- u32 key)
+ u32 key,
+ struct dlm_protocol_version *fs_proto)
{
int ret;
struct dlm_ctxt *dlm = NULL;
@@ -1496,6 +1611,12 @@ retry:
goto retry;
}
+ if (dlm_protocol_compare(&dlm->fs_locking_proto, fs_proto)) {
+ mlog(ML_ERROR, "Requested locking protocol version is not compatible with already registered domain \"%s\"\n", domain);
+ ret = -EPROTO;
+ goto leave;
+ }
+
__dlm_get(dlm);
dlm->num_joins++;
@@ -1526,6 +1647,13 @@ retry:
list_add_tail(&dlm->list, &dlm_domains);
spin_unlock(&dlm_domain_lock);
+ /*
+ * Pass the locking protocol version into the join. If the join
+ * succeeds, it will have the negotiated protocol set.
+ */
+ dlm->dlm_locking_proto = dlm_protocol;
+ dlm->fs_locking_proto = *fs_proto;
+
ret = dlm_join_domain(dlm);
if (ret) {
mlog_errno(ret);
@@ -1533,6 +1661,9 @@ retry:
goto leave;
}
+ /* Tell the caller what locking protocol we negotiated */
+ *fs_proto = dlm->fs_locking_proto;
+
ret = 0;
leave:
if (new_ctxt)
diff --git a/fs/ocfs2/dlm/dlmfs.c b/fs/ocfs2/dlm/dlmfs.c
index 6639baa..dc6cab2 100644
--- a/fs/ocfs2/dlm/dlmfs.c
+++ b/fs/ocfs2/dlm/dlmfs.c
@@ -70,6 +70,16 @@ static struct kmem_cache *dlmfs_inode_cache;
struct workqueue_struct *user_dlm_worker;
/*
+ * This is the userdlmfs locking protocol version.
+ *
+ * See fs/ocfs2/dlmglue.c for more details on locking versions.
+ */
+static const struct dlm_protocol_version user_locking_protocol = {
+ .pv_major = 1,
+ .pv_minor = 0,
+};
+
+/*
* decodes a set of open flags into a valid lock level and a set of flags.
* returns < 0 if we have invalid flags
* flags which mean something to us:
@@ -416,6 +426,7 @@ static int dlmfs_mkdir(struct inode * dir,
struct qstr *domain = &dentry->d_name;
struct dlmfs_inode_private *ip;
struct dlm_ctxt *dlm;
+ struct dlm_protocol_version proto = user_locking_protocol;
mlog(0, "mkdir %.*s\n", domain->len, domain->name);
@@ -435,7 +446,7 @@ static int dlmfs_mkdir(struct inode * dir,
ip = DLMFS_I(inode);
- dlm = user_dlm_register_context(domain);
+ dlm = user_dlm_register_context(domain, &proto);
if (IS_ERR(dlm)) {
status = PTR_ERR(dlm);
mlog(ML_ERROR, "Error %d could not register domain \"%.*s\"\n",
diff --git a/fs/ocfs2/dlm/userdlm.c b/fs/ocfs2/dlm/userdlm.c
index 7d2f578..4cb1d3d 100644
--- a/fs/ocfs2/dlm/userdlm.c
+++ b/fs/ocfs2/dlm/userdlm.c
@@ -645,7 +645,8 @@ bail:
return status;
}
-struct dlm_ctxt *user_dlm_register_context(struct qstr *name)
+struct dlm_ctxt *user_dlm_register_context(struct qstr *name,
+ struct dlm_protocol_version *proto)
{
struct dlm_ctxt *dlm;
u32 dlm_key;
@@ -661,7 +662,7 @@ struct dlm_ctxt *user_dlm_register_context(struct qstr *name)
snprintf(domain, name->len + 1, "%.*s", name->len, name->name);
- dlm = dlm_register_domain(domain, dlm_key);
+ dlm = dlm_register_domain(domain, dlm_key, proto);
if (IS_ERR(dlm))
mlog_errno(PTR_ERR(dlm));
diff --git a/fs/ocfs2/dlm/userdlm.h b/fs/ocfs2/dlm/userdlm.h
index c400e93..39ec277 100644
--- a/fs/ocfs2/dlm/userdlm.h
+++ b/fs/ocfs2/dlm/userdlm.h
@@ -83,7 +83,8 @@ void user_dlm_write_lvb(struct inode *inode,
void user_dlm_read_lvb(struct inode *inode,
char *val,
unsigned int len);
-struct dlm_ctxt *user_dlm_register_context(struct qstr *name);
+struct dlm_ctxt *user_dlm_register_context(struct qstr *name,
+ struct dlm_protocol_version *proto);
void user_dlm_unregister_context(struct dlm_ctxt *dlm);
struct dlmfs_inode_private {
diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index c365206..d346e52 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -252,6 +252,31 @@ static struct ocfs2_lock_res_ops ocfs2_inode_open_lops = {
.flags = 0,
};
+/*
+ * This is the filesystem locking protocol version.
+ *
+ * Whenever the filesystem does new things with locks (adds or removes a
+ * lock, orders them differently, does different things underneath a lock),
+ * the version must be changed. The protocol is negotiated when joining
+ * the dlm domain. A node may join the domain if its major version is
+ * identical to all other nodes and its minor version is greater than
+ * or equal to all other nodes. When its minor version is greater than
+ * the other nodes, it will run at the minor version specified by the
+ * other nodes.
+ *
+ * If a locking change is made that will not be compatible with older
+ * versions, the major number must be increased and the minor version set
+ * to zero. If a change merely adds a behavior that can be disabled when
+ * speaking to older versions, the minor version must be increased. If a
+ * change adds a fully backwards compatible change (eg, LVB changes that
+ * are just ignored by older versions), the version does not need to be
+ * updated.
+ */
+static const struct dlm_protocol_version ocfs2_locking_protocol = {
+ .pv_major = 1,
+ .pv_minor = 0,
+};
+
static inline int ocfs2_is_inode_lock(struct ocfs2_lock_res *lockres)
{
return lockres->l_type == OCFS2_LOCK_TYPE_META ||
@@ -2239,7 +2264,9 @@ int ocfs2_dlm_init(struct ocfs2_super *osb)
dlm_key = crc32_le(0, osb->uuid_str, strlen(osb->uuid_str));
/* for now, uuid == domain */
- dlm = dlm_register_domain(osb->uuid_str, dlm_key);
+ osb->osb_locking_proto = ocfs2_locking_protocol;
+ dlm = dlm_register_domain(osb->uuid_str, dlm_key,
+ &osb->osb_locking_proto);
if (IS_ERR(dlm)) {
status = PTR_ERR(dlm);
mlog_errno(status);
diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index f8f8661..e50bb61 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -247,6 +247,7 @@ struct ocfs2_super
struct ocfs2_lock_res osb_rename_lockres;
struct dlm_eviction_cb osb_eviction_cb;
struct ocfs2_dlm_debug *osb_dlm_debug;
+ struct dlm_protocol_version osb_locking_proto;
struct dentry *osb_debug_root;
--
"Up and down that road in our worn out shoes,
Talking bout good things and singing the blues."
Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker at oracle.com
Phone: (650) 506-8127
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