glusterd/mgmt_v3 locks: Handling different entities with mgmt_v3_locks.

Within the same namespace allowing mgmt_v3 lock engine to handle
entities of valid types. Postfixing the element's name with the entity
type allows us to perform locking operations on different elements
of different entitites at the same time.

For example: A volume named test, will acquire a lock on the name test_vol,
while a snap named test will acquire lock on the name test_snap, and thus be
allowed to co-exist in the same namespace.

Change-Id: I611d1a59b707e497d35a37bdca5a66e29a1b6f06
Signed-off-by: Avra Sengupta <asengupt@redhat.com>
Reviewed-on: http://review.gluster.org/7188
Reviewed-by: Rajesh Joseph <rjoseph@redhat.com>
Tested-by: Rajesh Joseph <rjoseph@redhat.com>

7 files changed, 111 insertions, 43 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-handler.c b/xlators/mgmt/glusterd/src/glusterd-handler.c
index c0325f0a9..f0316e732 100644
--- a/xlators/mgmt/glusterd/src/glusterd-handler.c
+++ b/xlators/mgmt/glusterd/src/glusterd-handler.c
@@ -671,7 +671,7 @@ glusterd_op_txn_begin (rpcsvc_request_t *req, glusterd_op_t op, void *ctx,
                                 goto out;
                 }
 
-                ret = glusterd_mgmt_v3_lock (volname, MY_UUID);
+                ret = glusterd_mgmt_v3_lock (volname, MY_UUID, "vol");
                 if (ret) {
                         gf_log (this->name, GF_LOG_ERROR,
                                 "Unable to acquire lock for %s", volname);
@@ -722,7 +722,8 @@ out:
                 if (priv->op_version < 3)
                         glusterd_unlock (MY_UUID);
                 else {
-                        ret = glusterd_mgmt_v3_unlock (volname, MY_UUID);
+                        ret = glusterd_mgmt_v3_unlock (volname, MY_UUID,
+                                                       "vol");
                         if (ret)
                                 gf_log (this->name, GF_LOG_ERROR,
                                         "Unable to release lock for %s",
@@ -4070,7 +4071,8 @@ __glusterd_peer_rpc_notify (struct rpc_clnt *rpc, void *mydata,
                 if (peerinfo->connected) {
                         list_for_each_entry (volinfo, &conf->volumes, vol_list) {
                                 ret = glusterd_mgmt_v3_unlock (volinfo->volname,
-                                                               peerinfo->uuid);
+                                                               peerinfo->uuid,
+                                                               "vol");
                                 if (ret)
                                         gf_log (this->name, GF_LOG_TRACE,
                                                 "Lock not released for %s",
diff --git a/xlators/mgmt/glusterd/src/glusterd-locks.c b/xlators/mgmt/glusterd/src/glusterd-locks.c
index d2601ebb8..f5636a0f6 100644
--- a/xlators/mgmt/glusterd/src/glusterd-locks.c
+++ b/xlators/mgmt/glusterd/src/glusterd-locks.c
@@ -26,8 +26,30 @@
 
 #include <signal.h>
 
+/* Valid entities that the mgt_v3 lock can hold locks upon */
+char   *valid_types[] = { "vol", "snap", NULL };
+
 static dict_t *mgmt_v3_lock;
 
+/* Checks if the lock request is for a valid entity */
+gf_boolean_t
+glusterd_mgmt_v3_is_type_valid (char *type)
+{
+        int32_t         i   = 0;
+        gf_boolean_t    ret = _gf_false;
+
+        GF_ASSERT (type);
+
+        for (i = 0; valid_types[i]; i++) {
+                if (!strcmp (type, valid_types[i])) {
+                        ret = _gf_true;
+                        break;
+                }
+        }
+
+        return ret;
+}
+
 /* Initialize the global mgmt_v3 lock list(dict) when
  * glusterd is spawned */
 int32_t
@@ -116,7 +138,7 @@ glusterd_multiple_mgmt_v3_unlock (dict_t *dict, uuid_t uuid)
                         goto out;
                 }
 
-                ret = glusterd_mgmt_v3_unlock (volname, uuid);
+                ret = glusterd_mgmt_v3_unlock (volname, uuid, "vol");
                 if (ret) {
                         gf_log ("", GF_LOG_ERROR,
                                 "Failed to release lock for %s. ", volname);
@@ -148,7 +170,7 @@ glusterd_multiple_mgmt_v3_lock (dict_t *dict, uuid_t uuid)
 
         ret = dict_get_int32 (dict, "volcount", &volcount);
         if (ret) {
-                gf_log ("", GF_LOG_DEBUG, "Failed to get volcount"
+                gf_log ("", GF_LOG_ERROR, "Failed to get volcount"
                         "name");
                 goto out;
         }
@@ -166,7 +188,7 @@ glusterd_multiple_mgmt_v3_lock (dict_t *dict, uuid_t uuid)
                         goto out;
                 }
 
-                ret = glusterd_mgmt_v3_lock (volname, uuid);
+                ret = glusterd_mgmt_v3_lock (volname, uuid, "vol");
                 if (ret) {
                         gf_log ("", GF_LOG_ERROR,
                                 "Failed to acquire lock for %s "
@@ -193,7 +215,7 @@ glusterd_multiple_mgmt_v3_lock (dict_t *dict, uuid_t uuid)
                                 goto out;
                         }
 
-                        ret = glusterd_mgmt_v3_unlock (volname, uuid);
+                        ret = glusterd_mgmt_v3_unlock (volname, uuid, "vol");
                         if (ret)
                                 gf_log ("", GF_LOG_ERROR,
                                         "Failed to release lock for %s.",
@@ -208,21 +230,39 @@ out:
 }
 
 int32_t
-glusterd_mgmt_v3_lock (char *key, uuid_t uuid)
+glusterd_mgmt_v3_lock (const char *name, uuid_t uuid, char *type)
 {
-        int32_t              ret      = -1;
-        mgmt_v3_lock_obj    *lock_obj = NULL;
-        uuid_t               owner    = {0};
+        char                 key[PATH_MAX] = "";
+        int32_t              ret           = -1;
+        mgmt_v3_lock_obj    *lock_obj      = NULL;
+        gf_boolean_t         is_valid      = _gf_true;
+        uuid_t               owner         = {0};
+
+        if (!name || !type) {
+                gf_log (THIS->name, GF_LOG_ERROR, "name or type is null.");
+                ret = -1;
+                goto out;
+        }
 
-        if (!key) {
-                gf_log (THIS->name, GF_LOG_ERROR, "key is null.");
+        is_valid = glusterd_mgmt_v3_is_type_valid (type);
+        if (is_valid != _gf_true) {
+                gf_log ("", GF_LOG_ERROR,
+                        "Invalid entity. Cannot perform locking "
+                        "operation on %s types", type);
                 ret = -1;
                 goto out;
         }
 
-        gf_log (THIS->name, GF_LOG_TRACE,
-                "Trying to acquire lock of %s for %s",
-                key, uuid_utoa (uuid));
+        ret = snprintf (key, sizeof(key), "%s_%s", name, type);
+        if (ret != strlen(name) + 1 + strlen(type)) {
+                ret = -1;
+                gf_log (THIS->name, GF_LOG_ERROR, "Unable to create key");
+                goto out;
+        }
+
+        gf_log (THIS->name, GF_LOG_DEBUG,
+                "Trying to acquire lock of %s %s for %s as %s",
+                type, name, uuid_utoa (uuid), key);
 
         ret = glusterd_get_mgmt_v3_lock_owner (key, &owner);
         if (ret) {
@@ -235,7 +275,7 @@ glusterd_mgmt_v3_lock (char *key, uuid_t uuid)
          * we fail */
         if (!uuid_is_null (owner)) {
                 gf_log (THIS->name, GF_LOG_ERROR, "Lock for %s held by %s",
-                        key, uuid_utoa (owner));
+                        name, uuid_utoa (owner));
                 ret = -1;
                 goto out;
         }
@@ -259,8 +299,9 @@ glusterd_mgmt_v3_lock (char *key, uuid_t uuid)
                 goto out;
         }
 
-        gf_log (THIS->name, GF_LOG_DEBUG, "Lock for %s successfully held by %s",
-                key, uuid_utoa (uuid));
+        gf_log (THIS->name, GF_LOG_DEBUG,
+                "Lock for %s %s successfully held by %s",
+                type, name, uuid_utoa (uuid));
 
         ret = 0;
 out:
@@ -269,19 +310,39 @@ out:
 }
 
 int32_t
-glusterd_mgmt_v3_unlock (char *key, uuid_t uuid)
+glusterd_mgmt_v3_unlock (const char *name, uuid_t uuid, char *type)
 {
-        int32_t        ret      = -1;
-        uuid_t         owner    = {0};
+        char           key[PATH_MAX] = "";
+        int32_t        ret           = -1;
+        gf_boolean_t   is_valid      = _gf_true;
+        uuid_t         owner         = {0};
+
+        if (!name || !type) {
+                gf_log (THIS->name, GF_LOG_ERROR, "name is null.");
+                ret = -1;
+                goto out;
+        }
+
+        is_valid = glusterd_mgmt_v3_is_type_valid (type);
+        if (is_valid != _gf_true) {
+                gf_log ("", GF_LOG_ERROR,
+                        "Invalid entity. Cannot perform unlocking "
+                        "operation on %s types", type);
+                ret = -1;
+                goto out;
+        }
 
-        if (!key) {
-                gf_log (THIS->name, GF_LOG_ERROR, "key is null.");
+        ret = snprintf (key, sizeof(key), "%s_%s",
+                        name, type);
+        if (ret != strlen(name) + 1 + strlen(type)) {
+                gf_log (THIS->name, GF_LOG_ERROR, "Unable to create key");
                 ret = -1;
                 goto out;
         }
 
-        gf_log (THIS->name, GF_LOG_TRACE, "Trying to release lock of %s for %s",
-                key, uuid_utoa (uuid));
+        gf_log (THIS->name, GF_LOG_DEBUG,
+                "Trying to release lock of %s %s for %s as %s",
+                type, name, uuid_utoa (uuid), key);
 
         ret = glusterd_get_mgmt_v3_lock_owner (key, &owner);
         if (ret) {
@@ -292,7 +353,7 @@ glusterd_mgmt_v3_unlock (char *key, uuid_t uuid)
 
         if (uuid_is_null (owner)) {
                 gf_log (THIS->name, GF_LOG_ERROR,
-                        "Lock for %s not held", key);
+                        "Lock for %s %s not held", type, name);
                 ret = -1;
                 goto out;
         }
@@ -301,16 +362,17 @@ glusterd_mgmt_v3_unlock (char *key, uuid_t uuid)
         if (ret) {
 
                 gf_log (THIS->name, GF_LOG_ERROR, "Lock owner mismatch. "
-                        "Lock for %s held by %s",
-                        key, uuid_utoa (owner));
+                        "Lock for %s %s held by %s",
+                        type, name, uuid_utoa (owner));
                 goto out;
         }
 
         /* Removing the mgmt_v3 lock from the global list */
         dict_del (mgmt_v3_lock, key);
 
-        gf_log (THIS->name, GF_LOG_DEBUG, "Lock for %s successfully released",
-                key);
+        gf_log (THIS->name, GF_LOG_DEBUG,
+                "Lock for %s %s successfully released",
+                type, name);
 
         ret = 0;
 out:
diff --git a/xlators/mgmt/glusterd/src/glusterd-locks.h b/xlators/mgmt/glusterd/src/glusterd-locks.h
index 71339ed7f..9ca332fe9 100644
--- a/xlators/mgmt/glusterd/src/glusterd-locks.h
+++ b/xlators/mgmt/glusterd/src/glusterd-locks.h
@@ -29,10 +29,10 @@ int32_t
 glusterd_get_mgmt_v3_lock_owner (char *volname, uuid_t *uuid);
 
 int32_t
-glusterd_mgmt_v3_lock (char *key, uuid_t uuid);
+glusterd_mgmt_v3_lock (const char *key, uuid_t uuid, char *type);
 
 int32_t
-glusterd_mgmt_v3_unlock (char *key, uuid_t uuid);
+glusterd_mgmt_v3_unlock (const char *key, uuid_t uuid, char *type);
 
 int32_t
 glusterd_multiple_mgmt_v3_lock (dict_t *dict, uuid_t uuid);
diff --git a/xlators/mgmt/glusterd/src/glusterd-mgmt-handler.c b/xlators/mgmt/glusterd/src/glusterd-mgmt-handler.c
index 72181e963..5077a0092 100644
--- a/xlators/mgmt/glusterd/src/glusterd-mgmt-handler.c
+++ b/xlators/mgmt/glusterd/src/glusterd-mgmt-handler.c
@@ -74,7 +74,7 @@ glusterd_synctasked_mgmt_v3_lock (rpcsvc_request_t *req,
                                 "Failed to get volname");
                         goto out;
                 }
-                ret = glusterd_mgmt_v3_lock (volname, ctx->uuid);
+                ret = glusterd_mgmt_v3_lock (volname, ctx->uuid, "vol");
 
                 if (ret)
                         gf_log (this->name, GF_LOG_ERROR,
@@ -755,7 +755,7 @@ glusterd_synctasked_mgmt_v3_unlock (rpcsvc_request_t *req,
                                 "Failed to get volname");
                         goto out;
                 }
-                ret = glusterd_mgmt_v3_unlock (volname, ctx->uuid);
+                ret = glusterd_mgmt_v3_unlock (volname, ctx->uuid, "vol");
                 if (ret)
                         gf_log (this->name, GF_LOG_ERROR,
                                 "Unable to release lock for %s", volname);
diff --git a/xlators/mgmt/glusterd/src/glusterd-mgmt.c b/xlators/mgmt/glusterd/src/glusterd-mgmt.c
index 7359169dd..e895f6e4f 100644
--- a/xlators/mgmt/glusterd/src/glusterd-mgmt.c
+++ b/xlators/mgmt/glusterd/src/glusterd-mgmt.c
@@ -313,7 +313,7 @@ glusterd_mgmt_v3_initiate_lockdown (glusterd_conf_t  *conf, glusterd_op_t op,
                         goto out;
                 }
         } else {
-                ret = glusterd_mgmt_v3_lock (volname, MY_UUID);
+                ret = glusterd_mgmt_v3_lock (volname, MY_UUID, "vol");
                 if (ret) {
                         gf_log (this->name, GF_LOG_ERROR,
                                 "Unable to acquire local lock for %s", volname);
@@ -1452,7 +1452,7 @@ out:
                         gf_log ("", GF_LOG_ERROR,
                                 "Failed to release mgmt_v3 locks on localhost");
         } else {
-                ret = glusterd_mgmt_v3_unlock (volname, MY_UUID);
+                ret = glusterd_mgmt_v3_unlock (volname, MY_UUID, "vol");
                 if (ret)
                         gf_log (this->name, GF_LOG_ERROR,
                                 "Unable to release local lock for %s", volname);
@@ -1646,7 +1646,7 @@ out:
                         gf_log ("", GF_LOG_ERROR,
                                 "Failed to release mgmt_v3 locks on localhost");
         } else {
-                ret = glusterd_mgmt_v3_unlock (volname, MY_UUID);
+                ret = glusterd_mgmt_v3_unlock (volname, MY_UUID, "vol");
                 if (ret)
                         gf_log (this->name, GF_LOG_ERROR,
                                 "Unable to release local lock for %s", volname);
diff --git a/xlators/mgmt/glusterd/src/glusterd-op-sm.c b/xlators/mgmt/glusterd/src/glusterd-op-sm.c
index 05e4b71a0..1666f5e4d 100644
--- a/xlators/mgmt/glusterd/src/glusterd-op-sm.c
+++ b/xlators/mgmt/glusterd/src/glusterd-op-sm.c
@@ -2749,7 +2749,8 @@ glusterd_op_ac_lock (glusterd_op_sm_event_t *event, void *ctx)
                         gf_log (this->name, GF_LOG_ERROR,
                                 "Unable to acquire volname");
                 else {
-                        ret = glusterd_mgmt_v3_lock (volname, lock_ctx->uuid);
+                        ret = glusterd_mgmt_v3_lock (volname, lock_ctx->uuid,
+                                                     "vol");
                         if (ret)
                                 gf_log (this->name, GF_LOG_ERROR,
                                         "Unable to acquire lock for %s",
@@ -2796,7 +2797,8 @@ glusterd_op_ac_unlock (glusterd_op_sm_event_t *event, void *ctx)
                         gf_log (this->name, GF_LOG_ERROR,
                                 "Unable to acquire volname");
                 else {
-                        ret = glusterd_mgmt_v3_unlock (volname, lock_ctx->uuid);
+                        ret = glusterd_mgmt_v3_unlock (volname, lock_ctx->uuid,
+                                                       "vol");
                         if (ret)
                                 gf_log (this->name, GF_LOG_ERROR,
                                         "Unable to release lock for %s", volname);
@@ -4082,7 +4084,8 @@ glusterd_op_txn_complete (uuid_t *txn_id)
                                 "Unable to acquire volname");
 
                 if (volname) {
-                        ret = glusterd_mgmt_v3_unlock (volname, MY_UUID);
+                        ret = glusterd_mgmt_v3_unlock (volname, MY_UUID,
+                                                       "vol");
                         if (ret)
                                 gf_log (this->name, GF_LOG_ERROR,
                                         "Unable to release lock for %s",
diff --git a/xlators/mgmt/glusterd/src/glusterd-syncop.c b/xlators/mgmt/glusterd/src/glusterd-syncop.c
index beab4aca7..438df8266 100644
--- a/xlators/mgmt/glusterd/src/glusterd-syncop.c
+++ b/xlators/mgmt/glusterd/src/glusterd-syncop.c
@@ -1336,7 +1336,8 @@ out:
                 if (conf->op_version < 3)
                         glusterd_unlock (MY_UUID);
                 else {
-                        ret = glusterd_mgmt_v3_unlock (volname, MY_UUID);
+                        ret = glusterd_mgmt_v3_unlock (volname, MY_UUID,
+                                                       "vol");
                         if (ret)
                                 gf_log (this->name, GF_LOG_ERROR,
                                         "Unable to release lock for %s",
@@ -1527,7 +1528,7 @@ gd_sync_task_begin (dict_t *op_ctx, rpcsvc_request_t * req)
                                 goto out;
                 }
 
-                ret = glusterd_mgmt_v3_lock (volname, MY_UUID);
+                ret = glusterd_mgmt_v3_lock (volname, MY_UUID, "vol");
                 if (ret) {
                         gf_log (this->name, GF_LOG_ERROR,
                                 "Unable to acquire lock for %s", volname);