cluster/tier: add pause tier for snapshots

Snaps of tiered volumes cannot handle files undergoing migration.
We implement a helper mechanism to "pause" migration. Any files
undergoing migration are aborted. Clean up is done to remove
sticky bits and data at the destination. Migration is restarted
after snap completes.

For testing an internal switch is added. It is not exposed externally.

gluster volume set vol1 tier-pause [true|false]

Change-Id: Ia85bbf89ac142e9b7e73fcbef98bb9da86097799
BUG: 1267950
Signed-off-by: Dan Lambright <dlambrig@redhat.com>
Reviewed-on: http://review.gluster.org/12304
Reviewed-by: N Balachandran <nbalacha@redhat.com>
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Tested-by: Gluster Build System <jenkins@build.gluster.com>

3 files changed, 201 insertions, 4 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-messages.h b/xlators/mgmt/glusterd/src/glusterd-messages.h
index 03826b7d748..ffcfa7773e9 100644
--- a/xlators/mgmt/glusterd/src/glusterd-messages.h
+++ b/xlators/mgmt/glusterd/src/glusterd-messages.h
@@ -40,7 +40,9 @@
  */
 
 #define GLUSTERD_COMP_BASE      GLFS_MSGID_GLUSTERD
-#define GLFS_NUM_MESSAGES       571
+
+#define GLFS_NUM_MESSAGES       573
+
 #define GLFS_MSGID_END          (GLUSTERD_COMP_BASE + GLFS_NUM_MESSAGES + 1)
 /* Messaged with message IDs */
 #define glfs_msg_start_x GLFS_COMP_BASE, "Invalid: Start of messages"
@@ -4611,8 +4613,26 @@
  * @recommendedaction
  *
  */
+
 #define GD_MSG_SHARED_STORAGE_DOES_NOT_EXIST        (GLUSTERD_COMP_BASE + 571)
 
+/*!
+ * @messageid
+ * @diagnosis
+ * @recommendedaction
+ *
+ */
+
+#define GD_MSG_SNAP_PAUSE_TIER_FAIL                 (GLUSTERD_COMP_BASE + 572)
+
+/*!
+ * @messageid
+ * @diagnosis
+ * @recommendedaction
+ *
+ */
+#define GD_MSG_SNAP_RESUME_TIER_FAIL                (GLUSTERD_COMP_BASE + 573)
+
 /*------------*/
 #define glfs_msg_end_x GLFS_MSGID_END, "Invalid: End of messages"
 #endif /* !_GLUSTERD_MESSAGES_H_ */
diff --git a/xlators/mgmt/glusterd/src/glusterd-snapshot.c b/xlators/mgmt/glusterd/src/glusterd-snapshot.c
index d185ba82979..90dac9e45de 100644
--- a/xlators/mgmt/glusterd/src/glusterd-snapshot.c
+++ b/xlators/mgmt/glusterd/src/glusterd-snapshot.c
@@ -1948,6 +1948,142 @@ out:
 }
 
 int
+glusterd_snapshot_pause_tier (xlator_t *this, glusterd_volinfo_t *volinfo)
+{
+        int                     ret             = -1;
+        dict_t                 *dict            = NULL;
+        char                   *op_errstr       = NULL;
+
+        GF_VALIDATE_OR_GOTO ("glusterd", this, out);
+        GF_VALIDATE_OR_GOTO (this->name, volinfo, out);
+
+        if (volinfo->type != GF_CLUSTER_TYPE_TIER) {
+                ret = 0;
+                goto out;
+        }
+
+        dict = dict_new ();
+        if (!dict) {
+                goto out;
+        }
+
+        ret = dict_set_int32 (dict, "rebalance-command",
+                              GF_DEFRAG_CMD_PAUSE_TIER);
+        if (ret) {
+                gf_msg (this->name, GF_LOG_ERROR, 0,
+                        GD_MSG_DICT_SET_FAILED,
+                        "Failed to set rebalance-command");
+                goto out;
+        }
+
+        ret = dict_set_str (dict, "volname", volinfo->volname);
+        if (ret) {
+                gf_msg (this->name, GF_LOG_ERROR, 0,
+                        GD_MSG_DICT_SET_FAILED,
+                        "Failed to set volname");
+                goto out;
+        }
+
+        ret = gd_brick_op_phase (GD_OP_DEFRAG_BRICK_VOLUME, NULL,
+                                 dict, &op_errstr);
+        if (ret) {
+                gf_msg (this->name, GF_LOG_ERROR, 0,
+                        GD_MSG_SNAP_PAUSE_TIER_FAIL,
+                        "Failed to pause tier. Errstr=%s",
+                        op_errstr);
+                goto out;
+        }
+
+out:
+        if (dict)
+                dict_unref (dict);
+
+        return ret;
+}
+
+
+int
+glusterd_snapshot_resume_tier (xlator_t *this, dict_t *snap_dict)
+{
+        int                     ret             = -1;
+        dict_t                 *dict            = NULL;
+        int64_t                 volcount        = 0;
+        char                    key[PATH_MAX]   = "";
+        char                   *volname         = NULL;
+        int                     i               = 0;
+        char                   *op_errstr       = NULL;
+        glusterd_volinfo_t     *volinfo         = NULL;
+
+        GF_VALIDATE_OR_GOTO ("glusterd", this, out);
+        GF_VALIDATE_OR_GOTO (this->name, snap_dict, out);
+
+        ret = dict_get_int64 (snap_dict, "volcount", &volcount);
+        if (ret) {
+                goto out;
+        }
+        if (volcount <= 0) {
+                ret = -1;
+                goto out;
+        }
+
+        dict = dict_new ();
+        if (!dict)
+                goto out;
+
+        for (i = 1; i <= volcount; i++) {
+                snprintf (key, sizeof (key), "volname%d", i);
+                ret = dict_get_str (snap_dict, key, &volname);
+                if (ret) {
+                        gf_msg (this->name, GF_LOG_ERROR, 0,
+                                GD_MSG_DICT_SET_FAILED,
+                                "Failed to get key %s", volname);
+                        goto out;
+                }
+
+                ret = glusterd_volinfo_find (volname, &volinfo);
+                if (ret)
+                        goto out;
+
+                if (volinfo->type != GF_CLUSTER_TYPE_TIER)
+                        continue;
+
+                ret = dict_set_int32 (dict, "rebalance-command",
+                                      GF_DEFRAG_CMD_RESUME_TIER);
+                if (ret) {
+                        gf_msg (this->name, GF_LOG_ERROR, 0,
+                                GD_MSG_DICT_SET_FAILED,
+                        "Failed to set rebalance-command");
+
+                        goto out;
+                }
+
+                ret = dict_set_str (dict, "volname", volname);
+                if (ret) {
+                        gf_msg (this->name, GF_LOG_ERROR, 0,
+                                GD_MSG_DICT_SET_FAILED,
+                                "Failed to set volname");
+                        goto out;
+                }
+
+                ret = gd_brick_op_phase (GD_OP_DEFRAG_BRICK_VOLUME, NULL,
+                                         dict, &op_errstr);
+                if (ret) {
+                        gf_msg (this->name, GF_LOG_ERROR, 0,
+                                GD_MSG_SNAP_RESUME_TIER_FAIL,
+                                "Failed to resume tier");
+                        goto out;
+                }
+        }
+
+out:
+        if (dict)
+                dict_unref (dict);
+
+        return ret;
+}
+
+
+int
 glusterd_snap_create_clone_common_prevalidate (dict_t *rsp_dict, int flags,
                                                char *snapname, char *err_str,
                                                char *snap_volname,
@@ -2249,7 +2385,12 @@ glusterd_snapshot_clone_prevalidate (dict_t *dict, char **op_errstr,
                 goto out;
         }
 
-        ret = 0;
+        ret = glusterd_snapshot_pause_tier (this, snap_vol);
+        if (ret) {
+                gf_msg (this->name, GF_LOG_ERROR, 0,
+                        GD_MSG_SNAP_PAUSE_TIER_FAIL,
+                        "Failed to pause tier in clone prevalidate.");
+        }
 out:
 
         if (ret && err_str[0] != '\0') {
@@ -2439,6 +2580,14 @@ glusterd_snapshot_create_prevalidate (dict_t *dict, char **op_errstr,
                         goto out;
                 }
 
+                ret = glusterd_snapshot_pause_tier (this, volinfo);
+                if (ret) {
+                        gf_msg (this->name, GF_LOG_ERROR, 0,
+                                GD_MSG_SNAP_PAUSE_TIER_FAIL,
+                                "Failed to pause tier in snap prevalidate.");
+                        goto out;
+                }
+
         }
 
         ret = dict_set_int64 (rsp_dict, "volcount", volcount);
@@ -2449,6 +2598,7 @@ glusterd_snapshot_create_prevalidate (dict_t *dict, char **op_errstr,
         }
 
         ret = 0;
+
 out:
         if (ret && err_str[0] != '\0') {
                 gf_msg (this->name, loglevel, 0,
@@ -7819,7 +7969,12 @@ glusterd_snapshot_clone_postvalidate (dict_t *dict, int32_t op_ret,
         }
         snap_vol->snapshot = NULL;
 
-        ret = 0;
+        ret = glusterd_snapshot_resume_tier (this, dict);
+        if (ret) {
+                gf_msg (this->name, GF_LOG_ERROR, 0,
+                        GD_MSG_SNAP_RESUME_TIER_FAIL,
+                        "Failed to resume tier in clone postvalidate.");
+        }
 
 out:
         return ret;
@@ -7914,7 +8069,13 @@ glusterd_snapshot_create_postvalidate (dict_t *dict, int32_t op_ret,
                 //ignore the errors of autodelete
                 ret = glusterd_handle_snap_limit (dict, rsp_dict);
         }
-        ret = 0;
+
+        ret = glusterd_snapshot_resume_tier (this, dict);
+        if (ret) {
+                gf_msg (this->name, GF_LOG_ERROR, 0,
+                        GD_MSG_SNAP_RESUME_TIER_FAIL,
+                        "Failed to resume tier in snapshot postvalidate.");
+        }
 
 out:
         return ret;
diff --git a/xlators/mgmt/glusterd/src/glusterd-volume-set.c b/xlators/mgmt/glusterd/src/glusterd-volume-set.c
index 58405b67363..d2ef4b184fb 100644
--- a/xlators/mgmt/glusterd/src/glusterd-volume-set.c
+++ b/xlators/mgmt/glusterd/src/glusterd-volume-set.c
@@ -47,6 +47,15 @@ validate_tier (glusterd_volinfo_t *volinfo, dict_t *dict, char *key,
                 goto out;
         }
 
+        else if (strstr (key, "tier-pause")) {
+                if (strcmp(value, "off") &&
+                    strcmp(value, "on")) {
+                        ret = -1;
+                        goto out;
+                }
+                goto out;
+        }
+
         /*
          * Rest of the volume set options for tier are expecting a positive
          * Integer. Change the function accordingly if this constraint is
@@ -1994,6 +2003,13 @@ struct volopt_map_entry glusterd_volopt_map[] = {
                          "file that has read hits less than this value will be "
                          "considered as COLD and will be demoted."
         },
+        { .key         = "cluster.tier-pause",
+          .voltype     = "cluster/tier",
+          .option      = "tier-pause",
+          .op_version  = GD_OP_VERSION_3_7_6,
+          .flags       = OPT_FLAG_CLIENT_OPT,
+          .validate_fn = validate_tier,
+        },
         { .key         = "cluster.tier-promote-frequency",
           .voltype     = "cluster/tier",
           .value       = "120",