cluster/tier: add pause tier for snapshots

This is a backport of 12304

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>
Signed-off-by: Dan Lambright <dlambrig@redhat.com>

Conflicts:
	xlators/mgmt/glusterd/src/glusterd-messages.h

Change-Id: I5f039d8d38a4c915bd873969f336b96755a0b8f1
BUG: 1274101
Reviewed-on: http://review.gluster.org/12411
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Dan Lambright <dlambrig@redhat.com>
Tested-by: Dan Lambright <dlambrig@redhat.com>

1 files changed, 164 insertions, 3 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-snapshot.c b/xlators/mgmt/glusterd/src/glusterd-snapshot.c
index a957377b1a6..19c1f439704 100644
--- a/xlators/mgmt/glusterd/src/glusterd-snapshot.c
+++ b/xlators/mgmt/glusterd/src/glusterd-snapshot.c
@@ -1953,6 +1953,142 @@ 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,
@@ -2254,7 +2390,12 @@ 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') {
@@ -2444,6 +2585,14 @@ 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);
@@ -2454,6 +2603,7 @@ 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,
@@ -7818,7 +7968,12 @@ 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;
@@ -7913,7 +8068,13 @@ 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;