support for de-commissioning a node using 'remove-brick'

to achieve this, we now create volume-file with
'decommissioned-nodes' option in distribute volume, then just
perform the rebalance set of operations (with 'force' flag set).

now onwards, the 'remove-brick' (with 'start' option) operation tries
to migrate data from removed bricks to existing bricks.

'remove-brick' also supports similar options as of replace-brick.

* (no options) -> works as 'force', will have the current behavior
         of remove-brick, ie., no data-migration, volume changes.

* start  (starts remove-brick with data-migration/draining process,
          which takes care of migrating data and once complete, will
          commit the changes to volume file)
* pause  (stop data migration, but keep the volume file intact with
          extra options whatever is set)
* abort  (stop data-migration, and fall back to old configuration)
* commit (if volume is stopped, commits the changes to volumefile)
* force  (stops the data-migration and commits the changes to
          volume file)

Change-Id: I3952bcfbe604a0952e68b6accace7014d5e401d3
BUG: 1952
Reviewed-on: http://review.gluster.com/118
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vijay@gluster.com>

9 files changed, 446 insertions, 130 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-brick-ops.c b/xlators/mgmt/glusterd/src/glusterd-brick-ops.c
index 8b3a03b6f..8832c69ed 100644
--- a/xlators/mgmt/glusterd/src/glusterd-brick-ops.c
+++ b/xlators/mgmt/glusterd/src/glusterd-brick-ops.c
@@ -312,7 +312,8 @@ glusterd_handle_remove_brick (rpcsvc_request_t *req)
                 strcpy (vol_type, "distribute");
 
 	/* Do not allow remove-brick if the volume is plain stripe */
-	if ((volinfo->type == GF_CLUSTER_TYPE_STRIPE) && (volinfo->brick_count == volinfo->sub_count)) {
+	if ((volinfo->type == GF_CLUSTER_TYPE_STRIPE) &&
+            (volinfo->brick_count == volinfo->sub_count)) {
                 snprintf (err_str, 2048, "Removing brick from a plain stripe is not allowed");
                 gf_log ("glusterd", GF_LOG_ERROR, "%s", err_str);
                 ret = -1;
@@ -321,8 +322,8 @@ glusterd_handle_remove_brick (rpcsvc_request_t *req)
 
 	/* Do not allow remove-brick if the bricks given is less than the replica count
 	   or stripe count */
-        if (((volinfo->type == GF_CLUSTER_TYPE_REPLICATE) || (volinfo->type == GF_CLUSTER_TYPE_STRIPE))
-	    && !(volinfo->brick_count <= volinfo->sub_count)) {
+        if ((volinfo->type != GF_CLUSTER_TYPE_NONE) &&
+            !(volinfo->brick_count <= volinfo->sub_count)) {
                 if (volinfo->sub_count && (count % volinfo->sub_count != 0)) {
                         snprintf (err_str, 2048, "Remove brick incorrect"
                                   " brick count of %d for %s %d",
@@ -512,16 +513,20 @@ out:
 
 
 int
-glusterd_op_perform_remove_brick (glusterd_volinfo_t  *volinfo, char *brick)
+glusterd_op_perform_remove_brick (glusterd_volinfo_t  *volinfo, char *brick,
+                                  int force, int *need_migrate)
 {
-
         glusterd_brickinfo_t    *brickinfo = NULL;
         char                    *dup_brick = NULL;
-        int32_t                 ret = -1;
+        int32_t                  ret = -1;
+        glusterd_conf_t         *priv = NULL;
 
         GF_ASSERT (volinfo);
         GF_ASSERT (brick);
 
+        priv = THIS->private;
+        GF_ASSERT (priv);
+
         dup_brick = gf_strdup (brick);
         if (!dup_brick)
                 goto out;
@@ -534,15 +539,26 @@ glusterd_op_perform_remove_brick (glusterd_volinfo_t  *volinfo, char *brick)
         if (ret)
                 goto out;
 
-        if (GLUSTERD_STATUS_STARTED == volinfo->status) {
-                ret = glusterd_brick_stop (volinfo, brickinfo);
-                if (ret) {
-                        gf_log ("", GF_LOG_ERROR, "Unable to stop "
-                                "glusterfs, ret: %d", ret);
-                        goto out;
+        if (!uuid_compare (brickinfo->uuid, priv->uuid)) {
+                /* Only if the brick is in this glusterd, do the rebalance */
+                if (need_migrate)
+                        *need_migrate = 1;
+        }
+
+        if (force) {
+                if (GLUSTERD_STATUS_STARTED == volinfo->status) {
+                        ret = glusterd_brick_stop (volinfo, brickinfo);
+                        if (ret) {
+                                gf_log (THIS->name, GF_LOG_ERROR, "Unable to stop "
+                                        "glusterfs, ret: %d", ret);
+                                goto out;
+                        }
                 }
+                glusterd_delete_brick (volinfo, brickinfo);
+                goto out;
         }
-        glusterd_delete_brick (volinfo, brickinfo);
+
+        brickinfo->decommissioned = 1;
 out:
         if (dup_brick)
                 GF_FREE (dup_brick);
@@ -700,17 +716,18 @@ out:
 }
 
 int
-glusterd_op_stage_remove_brick (dict_t *dict)
+glusterd_op_stage_remove_brick (dict_t *dict, char **op_errstr)
 {
-        int                                     ret = -1;
-        char                                    *volname = NULL;
-        glusterd_volinfo_t                      *volinfo = NULL;
-        dict_t                                  *ctx     = NULL;
-        char                                    *errstr  = NULL;
-        int32_t                                 brick_count = 0;
+        int                 ret         = -1;
+        char               *volname     = NULL;
+        glusterd_volinfo_t *volinfo     = NULL;
+        char               *errstr      = NULL;
+        int32_t             brick_count = 0;
+        char                msg[2048]   = {0,};
+        int32_t             flag        = 0;
+        gf1_op_commands     cmd         = GF_OP_CMD_NONE;
 
         ret = dict_get_str (dict, "volname", &volname);
-
         if (ret) {
                 gf_log ("", GF_LOG_ERROR, "Unable to get volume name");
                 goto out;
@@ -723,25 +740,64 @@ glusterd_op_stage_remove_brick (dict_t *dict)
                 goto out;
         }
 
-        if (glusterd_is_defrag_on(volinfo)) {
-                ctx = glusterd_op_get_ctx ();
-                errstr = gf_strdup("Rebalance is in progress. Please retry"
-                                    " after completion");
-                if (!errstr) {
-                        ret = -1;
+        ret = dict_get_int32 (dict, "command", &flag);
+        if (ret) {
+                gf_log ("", GF_LOG_ERROR, "Unable to get brick count");
+                goto out;
+        }
+        cmd = flag;
+
+        ret = -1;
+        switch (cmd) {
+        case GF_OP_CMD_NONE:
+                errstr = gf_strdup ("no remove-brick command issued");
+                goto out;
+
+        case GF_OP_CMD_STATUS:
+                ret = 0;
+                goto out;
+
+        case GF_OP_CMD_START:
+        {
+                if (GLUSTERD_STATUS_STARTED != volinfo->status) {
+                        snprintf (msg, sizeof (msg), "Volume %s needs to be started "
+                                  "before remove-brick (you can use 'force' or "
+                                  "'commit' to override this behavior)",
+                                  volinfo->volname);
+                        errstr = gf_strdup (msg);
+                        gf_log (THIS->name, GF_LOG_ERROR, "%s", errstr);
                         goto out;
                 }
-                gf_log ("glusterd", GF_LOG_ERROR, "%s", errstr);
-                ret = dict_set_dynstr (ctx, "errstr", errstr);
-                if (ret) {
-                        GF_FREE (errstr);
-                        gf_log ("", GF_LOG_DEBUG,
-                                "failed to set errstr ctx");
+                if (glusterd_is_defrag_on(volinfo)) {
+                        errstr = gf_strdup("Rebalance is in progress. Please retry"
+                                           " after completion");
+                        gf_log ("glusterd", GF_LOG_ERROR, "%s", errstr);
                         goto out;
                 }
+                break;
+        }
 
-                ret = -1;
-                goto out;
+        case GF_OP_CMD_PAUSE:
+        case GF_OP_CMD_ABORT:
+        {
+                if (!volinfo->decommission_in_progress) {
+                        errstr = gf_strdup("remove-brick is not in progress");
+                        gf_log ("glusterd", GF_LOG_ERROR, "%s", errstr);
+                        goto out;
+                }
+                break;
+        }
+
+        case GF_OP_CMD_COMMIT:
+                if (volinfo->decommission_in_progress) {
+                        errstr = gf_strdup ("use 'force' option as migration "
+                                            "is in progress");
+                        goto out;
+                }
+                break;
+
+        case GF_OP_CMD_COMMIT_FORCE:
+                break;
         }
 
         ret = dict_get_int32 (dict, "count", &brick_count);
@@ -750,41 +806,96 @@ glusterd_op_stage_remove_brick (dict_t *dict)
                 goto out;
         }
 
+        ret = 0;
         if (volinfo->brick_count == brick_count) {
-                ctx = glusterd_op_get_ctx ();
-                if (!ctx) {
-                        gf_log ("", GF_LOG_ERROR,
-                                "Operation Context is not present");
-                        ret = -1;
-                        goto out;
-                }
                 errstr = gf_strdup ("Deleting all the bricks of the "
                                     "volume is not allowed");
-                if (!errstr) {
-                        gf_log ("", GF_LOG_ERROR, "Out of memory");
-                        ret = -1;
-                        goto out;
-                }
-
-                ret = dict_set_dynstr (ctx, "errstr", errstr);
-                if (ret) {
-                        GF_FREE (errstr);
-                        gf_log ("", GF_LOG_DEBUG,
-                                "failed to set pump status in ctx");
-                        goto out;
-                }
-
                 ret = -1;
                 goto out;
         }
 
 out:
         gf_log ("", GF_LOG_DEBUG, "Returning %d", ret);
+        if (ret && errstr) {
+                if (op_errstr)
+                        *op_errstr = errstr;
+        }
 
         return ret;
 }
 
 int
+glusterd_remove_brick_migrate_cbk (glusterd_volinfo_t *volinfo,
+                                   gf_defrag_status_t status)
+{
+        int                   ret = 0;
+        glusterd_brickinfo_t *brickinfo = NULL;
+        glusterd_brickinfo_t *tmp = NULL;
+
+        switch (status) {
+        case GF_DEFRAG_STATUS_PAUSED:
+        case GF_DEFRAG_STATUS_FAILED:
+                /* No changes required in the volume file.
+                   everything should remain as is */
+                break;
+        case GF_DEFRAG_STATUS_STOPPED:
+                /* Fall back to the old volume file */
+                list_for_each_entry_safe (brickinfo, tmp, &volinfo->bricks, brick_list) {
+                        if (!brickinfo->decommissioned)
+                                continue;
+                        brickinfo->decommissioned = 0;
+                }
+                break;
+
+        case GF_DEFRAG_STATUS_COMPLETE:
+                /* Done with the task, you can remove the brick from the
+                   volume file */
+                list_for_each_entry_safe (brickinfo, tmp, &volinfo->bricks, brick_list) {
+                        if (!brickinfo->decommissioned)
+                                continue;
+                        gf_log (THIS->name, GF_LOG_INFO, "removing the brick %s",
+                                brickinfo->path);
+                        brickinfo->decommissioned = 0;
+                        if (GLUSTERD_STATUS_STARTED == volinfo->status) {
+                                ret = glusterd_brick_stop (volinfo, brickinfo);
+                                if (ret) {
+                                        gf_log (THIS->name, GF_LOG_ERROR,
+                                                "Unable to stop glusterfs (%d)", ret);
+                                }
+                        }
+                        glusterd_delete_brick (volinfo, brickinfo);
+                }
+                break;
+
+        default:
+                GF_ASSERT (!"cbk function called with wrong status");
+                break;
+        }
+
+        ret = glusterd_create_volfiles_and_notify_services (volinfo);
+        if (ret)
+                gf_log (THIS->name, GF_LOG_ERROR,
+                        "Unable to write volume files (%d)", ret);
+
+        ret = glusterd_store_volinfo (volinfo, GLUSTERD_VOLINFO_VER_AC_INCREMENT);
+        if (ret)
+                gf_log (THIS->name, GF_LOG_ERROR,
+                        "Unable to store volume info (%d)", ret);
+
+
+        if (GLUSTERD_STATUS_STARTED == volinfo->status) {
+                ret = glusterd_check_generate_start_nfs ();
+                if (ret)
+                        gf_log (THIS->name, GF_LOG_ERROR,
+                                "Unable to start nfs process (%d)", ret);
+        }
+
+        volinfo->decommission_in_progress = 0;
+        return 0;
+}
+
+
+int
 glusterd_op_add_brick (dict_t *dict, char **op_errstr)
 {
         int                                     ret = 0;
@@ -848,15 +959,20 @@ out:
 }
 
 int
-glusterd_op_remove_brick (dict_t *dict)
+glusterd_op_remove_brick (dict_t *dict, char **op_errstr)
 {
-        int                                     ret = -1;
-        char                                    *volname = NULL;
-        glusterd_volinfo_t                      *volinfo = NULL;
-        char                                    *brick = NULL;
-        int32_t                                 count = 0;
-        int32_t                                 i = 1;
-        char                                    key[256] = {0,};
+        int                 ret            = -1;
+        char               *volname        = NULL;
+        glusterd_volinfo_t *volinfo        = NULL;
+        char               *brick          = NULL;
+        int32_t             count          = 0;
+        int32_t             i              = 1;
+        char                key[256]       = {0,};
+        int32_t             flag           = 0;
+        char                err_str[4096]  = {0,};
+        int                 need_rebalance = 0;
+        int                 force          = 0;
+        gf1_op_commands     cmd            = 0;
 
         ret = dict_get_str (dict, "volname", &volname);
 
@@ -866,12 +982,99 @@ glusterd_op_remove_brick (dict_t *dict)
         }
 
         ret = glusterd_volinfo_find (volname, &volinfo);
-
         if (ret) {
                 gf_log ("", GF_LOG_ERROR, "Unable to allocate memory");
                 goto out;
         }
 
+        ret = dict_get_int32 (dict, "command", &flag);
+        if (ret) {
+                gf_log ("", GF_LOG_ERROR, "Unable to get brick count");
+                goto out;
+        }
+        cmd = flag;
+
+        ret = -1;
+        switch (cmd) {
+        case GF_OP_CMD_NONE:
+                goto out;
+
+        case GF_OP_CMD_STATUS:
+                ret = 0;
+                goto out;
+
+        case GF_OP_CMD_PAUSE:
+        {
+                if (volinfo->decommission_in_progress) {
+                        if (volinfo->defrag == (void *)1)
+                                volinfo->defrag = NULL;
+
+                        if (volinfo->defrag) {
+                                LOCK (&volinfo->defrag->lock);
+
+                                volinfo->defrag_status = GF_DEFRAG_STATUS_PAUSED;
+
+                                UNLOCK (&volinfo->defrag->lock);
+                        }
+                }
+
+                /* rebalance '_cbk()' will take care of volume file updates */
+                ret = 0;
+                goto out;
+        }
+
+        case GF_OP_CMD_ABORT:
+        {
+                if (volinfo->decommission_in_progress) {
+                        if (volinfo->defrag == (void *)1)
+                                volinfo->defrag = NULL;
+
+                        if (volinfo->defrag) {
+                                LOCK (&volinfo->defrag->lock);
+
+                                volinfo->defrag_status = GF_DEFRAG_STATUS_STOPPED;
+
+                                UNLOCK (&volinfo->defrag->lock);
+                        }
+                }
+
+                /* rebalance '_cbk()' will take care of volume file updates */
+                ret = 0;
+                goto out;
+        }
+
+        case GF_OP_CMD_START:
+                force = 0;
+                break;
+
+        case GF_OP_CMD_COMMIT:
+                force = 1;
+                break;
+
+        case GF_OP_CMD_COMMIT_FORCE:
+
+                if (volinfo->decommission_in_progress) {
+                        if (volinfo->defrag == (void *)1)
+                                volinfo->defrag = NULL;
+
+                        if (volinfo->defrag) {
+                                LOCK (&volinfo->defrag->lock);
+                                /* Fake 'rebalance-complete' so the graph change
+                                   happens right away */
+                                volinfo->defrag_status = GF_DEFRAG_STATUS_COMPLETE;
+
+                                UNLOCK (&volinfo->defrag->lock);
+                        }
+                        ret = 0;
+                        /* Graph change happens in rebalance _cbk function,
+                           no need to do anything here */
+                        goto out;
+                }
+
+                force = 1;
+                break;
+        }
+
         ret = dict_get_int32 (dict, "count", &count);
         if (ret) {
                 gf_log ("", GF_LOG_ERROR, "Unable to get count");
@@ -887,26 +1090,46 @@ glusterd_op_remove_brick (dict_t *dict)
                         goto out;
                 }
 
-                ret = glusterd_op_perform_remove_brick (volinfo, brick);
+                ret = glusterd_op_perform_remove_brick (volinfo, brick, force,
+                                                        (i == 1) ? &need_rebalance : NULL);
                 if (ret)
                         goto out;
                 i++;
         }
 
         ret = glusterd_create_volfiles_and_notify_services (volinfo);
-        if (ret)
+        if (ret) {
+                gf_log (THIS->name, GF_LOG_WARNING, "failed to create volfiles");
                 goto out;
-
-        volinfo->defrag_status = 0;
+        }
 
         ret = glusterd_store_volinfo (volinfo, GLUSTERD_VOLINFO_VER_AC_INCREMENT);
-
-        if (ret)
+        if (ret) {
+                gf_log (THIS->name, GF_LOG_WARNING, "failed to store volinfo");
                 goto out;
+        }
 
-        if (GLUSTERD_STATUS_STARTED == volinfo->status)
-                ret = glusterd_check_generate_start_nfs ();
+        volinfo->defrag_status = 0;
+        if (!force && need_rebalance) {
+                /* perform the rebalance operations */
+                ret = glusterd_handle_defrag_start (volinfo, err_str, 4096,
+                                                    GF_DEFRAG_CMD_START_FORCE,
+                                                    glusterd_remove_brick_migrate_cbk);
+                if (!ret)
+                        volinfo->decommission_in_progress = 1;
+
+                if (ret) {
+                        gf_log (THIS->name, GF_LOG_ERROR,
+                                "failed to start the rebalance");
+                }
+        } else {
+                if (GLUSTERD_STATUS_STARTED == volinfo->status)
+                        ret = glusterd_check_generate_start_nfs ();
+        }
 
 out:
+        if (ret && err_str[0] && op_errstr)
+                *op_errstr = gf_strdup (err_str);
+
         return ret;
 }
diff --git a/xlators/mgmt/glusterd/src/glusterd-op-sm.c b/xlators/mgmt/glusterd/src/glusterd-op-sm.c
index 3b30fb080..53556984a 100644
--- a/xlators/mgmt/glusterd/src/glusterd-op-sm.c
+++ b/xlators/mgmt/glusterd/src/glusterd-op-sm.c
@@ -2297,7 +2297,7 @@ glusterd_op_stage_validate (glusterd_op_t op, dict_t *dict, char **op_errstr,
                         break;
 
                 case GD_OP_REMOVE_BRICK:
-                        ret = glusterd_op_stage_remove_brick (dict);
+                        ret = glusterd_op_stage_remove_brick (dict, op_errstr);
                         break;
 
                 case GD_OP_LOG_FILENAME:
@@ -2387,7 +2387,7 @@ glusterd_op_commit_perform (glusterd_op_t op, dict_t *dict, char **op_errstr,
                         break;
 
                 case GD_OP_REMOVE_BRICK:
-                        ret = glusterd_op_remove_brick (dict);
+                        ret = glusterd_op_remove_brick (dict, op_errstr);
                         break;
 
                 case GD_OP_LOG_FILENAME:
@@ -2565,6 +2565,7 @@ glusterd_bricks_select_remove_brick (dict_t *dict, char **op_errstr)
         int32_t                                 i = 1;
         char                                    key[256] = {0,};
         glusterd_pending_node_t                 *pending_node = NULL;
+        int32_t                                 force = 0;
 
         ret = dict_get_str (dict, "volname", &volname);
 
@@ -2586,6 +2587,12 @@ glusterd_bricks_select_remove_brick (dict_t *dict, char **op_errstr)
                 goto out;
         }
 
+        ret = dict_get_int32 (dict, "force", &force);
+        if (ret) {
+                gf_log (THIS->name, GF_LOG_INFO, "force flag is not set");
+                ret = 0;
+                goto out;
+        }
 
         while ( i <= count) {
                 snprintf (key, 256, "brick%d", i);
diff --git a/xlators/mgmt/glusterd/src/glusterd-rebalance.c b/xlators/mgmt/glusterd/src/glusterd-rebalance.c
index a013d0adf..defaf947f 100644
--- a/xlators/mgmt/glusterd/src/glusterd-rebalance.c
+++ b/xlators/mgmt/glusterd/src/glusterd-rebalance.c
@@ -46,6 +46,7 @@
 #include "cli1-xdr.h"
 #include "xdr-generic.h"
 
+/* return values - 0: success, +ve: stopped, -ve: failure */
 int
 gf_glusterd_rebalance_move_data (glusterd_volinfo_t *volinfo, const char *dir)
 {
@@ -66,7 +67,8 @@ gf_glusterd_rebalance_move_data (glusterd_volinfo_t *volinfo, const char *dir)
         if (!fd)
                 goto out;
 
-        if (defrag->cmd == GF_DEFRAG_CMD_START_MIGRATE_DATA_FORCE) {
+        if ((defrag->cmd == GF_DEFRAG_CMD_START_MIGRATE_DATA_FORCE) ||
+            (defrag->cmd == GF_DEFRAG_CMD_START_FORCE)) {
                 strcpy (force_string, "force");
         } else {
                 strcpy (force_string, "not-force");
@@ -105,9 +107,11 @@ gf_glusterd_rebalance_move_data (glusterd_volinfo_t *volinfo, const char *dir)
                 }
                 UNLOCK (&defrag->lock);
 
-                if (volinfo->defrag_status == GF_DEFRAG_STATUS_STOPED) {
+                if (volinfo->defrag_status !=
+                    GF_DEFRAG_STATUS_MIGRATE_DATA_STARTED) {
+                        /* It can be one of 'stopped|paused|commit' etc */
                         closedir (fd);
-                        ret = -1;
+                        ret = 1;
                         goto out;
                 }
         }
@@ -144,6 +148,7 @@ out:
         return ret;
 }
 
+/* return values - 0: success, +ve: stopped, -ve: failure */
 int
 gf_glusterd_rebalance_fix_layout (glusterd_volinfo_t *volinfo, const char *dir)
 {
@@ -187,9 +192,11 @@ gf_glusterd_rebalance_fix_layout (glusterd_volinfo_t *volinfo, const char *dir)
                                 break;
                 }
 
-                if (volinfo->defrag_status == GF_DEFRAG_STATUS_STOPED) {
+                if (volinfo->defrag_status !=
+                    GF_DEFRAG_STATUS_LAYOUT_FIX_STARTED) {
+                        /* It can be one of 'stopped|paused|commit' etc */
                         closedir (fd);
-                        ret = -1;
+                        ret = 1;
                         goto out;
                 }
         }
@@ -210,6 +217,7 @@ glusterd_defrag_start (void *data)
         int                     ret     = -1;
         struct stat             stbuf   = {0,};
 
+        THIS = volinfo->xl;
         defrag = volinfo->defrag;
         if (!defrag)
                 goto out;
@@ -240,8 +248,10 @@ glusterd_defrag_start (void *data)
 
                 /* Step 1: Fix layout of all the directories */
                 ret = gf_glusterd_rebalance_fix_layout (volinfo, defrag->mount);
+                if (ret < 0)
+                        volinfo->defrag_status = GF_DEFRAG_STATUS_FAILED;
+                /* in both 'stopped' or 'failure' cases goto out */
                 if (ret) {
-                        volinfo->defrag_status   = GF_DEFRAG_STATUS_FAILED;
                         goto out;
                 }
 
@@ -257,8 +267,10 @@ glusterd_defrag_start (void *data)
 
                 /* Step 2: Iterate over directories to move data */
                 ret = gf_glusterd_rebalance_move_data (volinfo, defrag->mount);
+                if (ret < 0)
+                        volinfo->defrag_status = GF_DEFRAG_STATUS_FAILED;
+                /* in both 'stopped' or 'failure' cases goto out */
                 if (ret) {
-                        volinfo->defrag_status   = GF_DEFRAG_STATUS_FAILED;
                         goto out;
                 }
 
@@ -267,7 +279,8 @@ glusterd_defrag_start (void *data)
         }
 
         /* Completed whole process */
-        if (defrag->cmd == GF_DEFRAG_CMD_START)
+        if ((defrag->cmd == GF_DEFRAG_CMD_START) ||
+            (defrag->cmd == GF_DEFRAG_CMD_START_FORCE))
                 volinfo->defrag_status = GF_DEFRAG_STATUS_COMPLETE;
 
         volinfo->rebalance_files = defrag->total_files;
@@ -281,9 +294,13 @@ out:
 
                 ret = runcmd ("umount", "-l", defrag->mount, NULL);
                 LOCK_DESTROY (&defrag->lock);
+
+                if (defrag->cbk_fn) {
+                        defrag->cbk_fn (volinfo, volinfo->defrag_status);
+                }
+
                 GF_FREE (defrag);
         }
-
         return NULL;
 }
 
@@ -332,7 +349,7 @@ glusterd_defrag_stop (glusterd_volinfo_t *volinfo, u_quad_t *files,
 
         LOCK (&volinfo->defrag->lock);
         {
-                volinfo->defrag_status = GF_DEFRAG_STATUS_STOPED;
+                volinfo->defrag_status = GF_DEFRAG_STATUS_STOPPED;
                 *files = volinfo->defrag->total_files;
                 *size = volinfo->defrag->total_data;
         }
@@ -497,7 +514,7 @@ out:
 
 int
 glusterd_handle_defrag_start (glusterd_volinfo_t *volinfo, char *op_errstr,
-                              size_t len, int cmd)
+                              size_t len, int cmd, defrag_cbk_fn_t cbk)
 {
         int                    ret = -1;
         glusterd_defrag_info_t *defrag =  NULL;
@@ -552,6 +569,9 @@ glusterd_handle_defrag_start (glusterd_volinfo_t *volinfo, char *op_errstr,
 
         volinfo->defrag_status = GF_DEFRAG_STATUS_LAYOUT_FIX_STARTED;
 
+        if (cbk)
+                defrag->cbk_fn = cbk;
+
         ret = pthread_create (&defrag->th, NULL, glusterd_defrag_start,
                               volinfo);
         if (ret) {
@@ -635,7 +655,7 @@ glusterd_handle_defrag_volume (rpcsvc_request_t *req)
         case GF_DEFRAG_CMD_START_MIGRATE_DATA_FORCE:
         {
                 ret = glusterd_handle_defrag_start (volinfo, msg, sizeof (msg),
-                                                    cli_req.cmd);
+                                                    cli_req.cmd, NULL);
                 rsp.op_ret = ret;
                 break;
         }
@@ -845,7 +865,7 @@ glusterd_op_rebalance (dict_t *dict, char **op_errstr, dict_t *rsp_dict)
         case GF_DEFRAG_CMD_START_MIGRATE_DATA:
         case GF_DEFRAG_CMD_START_MIGRATE_DATA_FORCE:
                 ret = glusterd_handle_defrag_start (volinfo, msg, sizeof (msg),
-                                                    cmd);
+                                                    cmd, NULL);
                  break;
          case GF_DEFRAG_CMD_STOP:
                  ret = glusterd_defrag_stop (volinfo, &files, &size,
diff --git a/xlators/mgmt/glusterd/src/glusterd-replace-brick.c b/xlators/mgmt/glusterd/src/glusterd-replace-brick.c
index 060d40bed..4a4289910 100644
--- a/xlators/mgmt/glusterd/src/glusterd-replace-brick.c
+++ b/xlators/mgmt/glusterd/src/glusterd-replace-brick.c
@@ -1486,7 +1486,7 @@ glusterd_op_perform_replace_brick (glusterd_volinfo_t  *volinfo,
 
         volinfo->brick_count++;
 
-        ret = glusterd_op_perform_remove_brick (volinfo, old_brick);
+        ret = glusterd_op_perform_remove_brick (volinfo, old_brick, 1, NULL);
         if (ret)
                 goto out;
 
diff --git a/xlators/mgmt/glusterd/src/glusterd-store.c b/xlators/mgmt/glusterd/src/glusterd-store.c
index 53fdcf484..dab075db0 100644
--- a/xlators/mgmt/glusterd/src/glusterd-store.c
+++ b/xlators/mgmt/glusterd/src/glusterd-store.c
@@ -321,6 +321,10 @@ glusterd_store_brickinfo_write (int fd, glusterd_brickinfo_t *brickinfo)
         ret = glusterd_store_save_value (fd, GLUSTERD_STORE_KEY_BRICK_RDMA_PORT,
                                          value);
 
+        snprintf (value, sizeof(value), "%d", brickinfo->decommissioned);
+        ret = glusterd_store_save_value (fd, GLUSTERD_STORE_KEY_BRICK_DECOMMISSIONED,
+                                         value);
+
 out:
         gf_log ("", GF_LOG_DEBUG, "Returning %d", ret);
         return ret;
@@ -1637,6 +1641,9 @@ glusterd_store_retrieve_bricks (glusterd_volinfo_t *volinfo)
                                 pmap = pmap_registry_get (THIS);
                                 if (pmap->last_alloc <= brickinfo->rdma_port)
                                         pmap->last_alloc = brickinfo->rdma_port + 1;
+                        } else if (!strncmp (key, GLUSTERD_STORE_KEY_BRICK_DECOMMISSIONED,
+                                             strlen (GLUSTERD_STORE_KEY_BRICK_DECOMMISSIONED))) {
+                                gf_string2int (value, &brickinfo->decommissioned);
                         } else {
                                 gf_log ("", GF_LOG_ERROR, "Unknown key: %s",
                                         key);
diff --git a/xlators/mgmt/glusterd/src/glusterd-store.h b/xlators/mgmt/glusterd/src/glusterd-store.h
index 3ca232a9a..61bda195d 100644
--- a/xlators/mgmt/glusterd/src/glusterd-store.h
+++ b/xlators/mgmt/glusterd/src/glusterd-store.h
@@ -63,6 +63,7 @@ typedef enum glusterd_store_ver_ac_{
 #define GLUSTERD_STORE_KEY_BRICK_PATH     "path"
 #define GLUSTERD_STORE_KEY_BRICK_PORT     "listen-port"
 #define GLUSTERD_STORE_KEY_BRICK_RDMA_PORT "rdma.listen-port"
+#define GLUSTERD_STORE_KEY_BRICK_DECOMMISSIONED "decommissioned"
 
 #define GLUSTERD_STORE_KEY_PEER_UUID      "uuid"
 #define GLUSTERD_STORE_KEY_PEER_HOSTNAME  "hostname"
diff --git a/xlators/mgmt/glusterd/src/glusterd-utils.c b/xlators/mgmt/glusterd/src/glusterd-utils.c
index 8694f7536..5b247b6a9 100644
--- a/xlators/mgmt/glusterd/src/glusterd-utils.c
+++ b/xlators/mgmt/glusterd/src/glusterd-utils.c
@@ -548,6 +548,8 @@ glusterd_volinfo_new (glusterd_volinfo_t **volinfo)
                 goto out;
         }
 
+        new_volinfo->xl = THIS;
+
         *volinfo = new_volinfo;
 
         ret = 0;
diff --git a/xlators/mgmt/glusterd/src/glusterd-volgen.c b/xlators/mgmt/glusterd/src/glusterd-volgen.c
index cb198dfb9..d0533b1fc 100644
--- a/xlators/mgmt/glusterd/src/glusterd-volgen.c
+++ b/xlators/mgmt/glusterd/src/glusterd-volgen.c
@@ -1811,10 +1811,15 @@ client_graph_builder (volgen_graph_t *graph, glusterd_volinfo_t *volinfo,
         char                   **cluster_args       = NULL;
         int                      i                  = 0;
         int                      j                  = 0;
-        int                      ret                = 0;
+        int                      ret                = -1;
         xlator_t                *xl                 = NULL;
         xlator_t                *txl                = NULL;
         xlator_t                *trav               = NULL;
+        int                      removed_bricks     = 0;
+        int                      index_of_removed_brick = 0;
+        char                    *removed_bricklist  = NULL;
+        char                     volume_name[1024]  = {0,};
+        int                      idx                = 0;
 
         volname = volinfo->volname;
         dict    = volinfo->dict;
@@ -1824,7 +1829,7 @@ client_graph_builder (volgen_graph_t *graph, glusterd_volinfo_t *volinfo,
                 gf_log ("", GF_LOG_ERROR,
                         "volume inconsistency: brick count is 0");
 
-                return -1;
+                goto out;
         }
         if (volinfo->sub_count && volinfo->sub_count < volinfo->brick_count &&
             volinfo->brick_count % volinfo->sub_count != 0) {
@@ -1834,7 +1839,7 @@ client_graph_builder (volgen_graph_t *graph, glusterd_volinfo_t *volinfo,
                         "number of bricks per cluster (%d) in a multi-cluster "
                         "setup",
                         volinfo->brick_count, volinfo->sub_count);
-                return -1;
+                goto out;
         }
 
         get_transport_type (volinfo, set_dict, transt, _gf_false);
@@ -1844,19 +1849,32 @@ client_graph_builder (volgen_graph_t *graph, glusterd_volinfo_t *volinfo,
 
         i = 0;
         list_for_each_entry (brick, &volinfo->bricks, brick_list) {
+                ret = -1;
                 xl = volgen_graph_add_nolink (graph, "protocol/client",
                                               "%s-client-%d", volname, i);
                 if (!xl)
-                        return -1;
+                        goto out;
                 ret = xlator_set_option (xl, "remote-host", brick->hostname);
                 if (ret)
-                        return -1;
+                        goto out;
                 ret = xlator_set_option (xl, "remote-subvolume", brick->path);
                 if (ret)
-                        return -1;
+                        goto out;
                 ret = xlator_set_option (xl, "transport-type", transt);
                 if (ret)
-                        return -1;
+                        goto out;
+                if (brick->decommissioned) {
+                        if (!removed_bricklist) {
+                                removed_bricklist = GF_CALLOC (16 * GF_UNIT_KB,
+                                                               1, gf_common_mt_char);
+                                index_of_removed_brick = i;
+                        }
+                        if (removed_bricks)
+                                strcat (removed_bricklist, ",");
+                        snprintf (volume_name, 1024, "%s-client-%d", volname, i);
+                        strcat (removed_bricklist, volume_name);
+                        removed_bricks++;
+                }
 
                 i++;
         }
@@ -1866,7 +1884,7 @@ client_graph_builder (volgen_graph_t *graph, glusterd_volinfo_t *volinfo,
                         "differs from brick count (%d)", i,
                         volinfo->brick_count);
 
-                return -1;
+                goto out;
         }
 
         sub_count = volinfo->sub_count;
@@ -1880,15 +1898,18 @@ client_graph_builder (volgen_graph_t *graph, glusterd_volinfo_t *volinfo,
                         break;
                 case GF_CLUSTER_TYPE_STRIPE_REPLICATE:
                         /* Replicate after the clients, then stripe */
-                        if (volinfo->replica_count == 0)
-                                return -1;
+                        if (volinfo->replica_count == 0) {
+                                ret = -1;
+                                goto out;
+                        }
                         sub_count = volinfo->replica_count;
                         cluster_args = replicate_args;
                         break;
                 default:
                         gf_log ("", GF_LOG_ERROR, "volume inconsistency: "
                                 "unrecognized clustering type");
-                        return -1;
+                        ret = -1;
+                        goto out;
                 }
 
                 i = 0;
@@ -1901,14 +1922,16 @@ client_graph_builder (volgen_graph_t *graph, glusterd_volinfo_t *volinfo,
                                                               cluster_args[0],
                                                               cluster_args[1],
                                                               volname, j);
-                                if (!xl)
-                                        return -1;
+                                if (!xl) {
+                                        ret = -1;
+                                        goto out;
+                                }
                                 j++;
                         }
 
                         ret = volgen_xlator_link (xl, trav);
                         if (ret)
-                                return -1;
+                                goto out;
 
                         if (trav == txl)
                                 break;
@@ -1928,14 +1951,16 @@ client_graph_builder (volgen_graph_t *graph, glusterd_volinfo_t *volinfo,
                                                                       cluster_args[0],
                                                                       cluster_args[1],
                                                                       volname, j);
-                                        if (!xl)
-                                                return -1;
+                                        if (!xl) {
+                                                ret = -1;
+                                                goto out;
+                                        }
                                         j++;
                                 }
 
                                 ret = volgen_xlator_link (xl, trav);
                                 if (ret)
-                                        return -1;
+                                        goto out;
 
                                 if (trav == txl)
                                         break;
@@ -1953,8 +1978,10 @@ client_graph_builder (volgen_graph_t *graph, glusterd_volinfo_t *volinfo,
         if (dist_count > 1) {
                 xl = volgen_graph_add_nolink (graph, "cluster/distribute",
                                               "%s-dht", volname);
-                if (!xl)
-                        return -1;
+                if (!xl) {
+                        ret = -1;
+                        goto out;
+                }
 
                 trav = xl;
                 for (i = 0; i < dist_count; i++)
@@ -1962,28 +1989,50 @@ client_graph_builder (volgen_graph_t *graph, glusterd_volinfo_t *volinfo,
                 for (; trav != xl; trav = trav->prev) {
                         ret = volgen_xlator_link (xl, trav);
                         if (ret)
-                                return -1;
+                                goto out;
+                }
+
+                if (removed_bricks) {
+                        if (volinfo->sub_count) {
+                                idx = index_of_removed_brick / volinfo->sub_count;
+                                if (GF_CLUSTER_TYPE_REPLICATE == volinfo->type) {
+                                        snprintf (volume_name, 1024, "%s-replicate-%d",
+                                                  volname, idx);
+                                        strcpy (removed_bricklist, volume_name);
+                                } else if (volinfo->type != GF_CLUSTER_TYPE_NONE) {
+                                        snprintf (volume_name, 1024, "%s-stripe-%d  ",
+                                                  volname, idx);
+                                        strcpy (removed_bricklist, volume_name);
+                                }
+                        }
+                        ret = xlator_set_option (xl, "decommissioned-bricks",
+                                                 removed_bricklist);
+                        if (ret)
+                                goto out;
                 }
         }
 
         ret = glusterd_volinfo_get_boolean (volinfo, VKEY_FEATURES_QUOTA);
         if (ret == -1)
-                return -1;
+                goto out;
+
         if (ret) {
                 xl = volgen_graph_add (graph, "features/quota", volname);
 
-                if (!xl)
-                        return -1;
+                if (!xl) {
+                        ret = -1;
+                        goto out;
+                }
         }
 
         ret = volgen_graph_set_options_generic (graph, set_dict, volname,
                                                 &perfxl_option_handler);
         if (ret)
-                return -1;
+                goto out;
 
         xl = volgen_graph_add_as (graph, "debug/io-stats", volname);
         if (!xl)
-                return -1;
+                goto out;
 
         ret = volgen_graph_set_options_generic (graph, set_dict, "client",
                                                 &loglevel_option_handler);
@@ -1991,6 +2040,11 @@ client_graph_builder (volgen_graph_t *graph, glusterd_volinfo_t *volinfo,
         if (!ret)
                 ret = volgen_graph_set_options_generic (graph, set_dict, "client",
                                                         &sys_loglevel_option_handler);
+
+out:
+        if (removed_bricklist)
+                GF_FREE (removed_bricklist);
+
         return ret;
 }
 
diff --git a/xlators/mgmt/glusterd/src/glusterd.h b/xlators/mgmt/glusterd/src/glusterd.h
index 86eeaeb1c..c8fa82819 100644
--- a/xlators/mgmt/glusterd/src/glusterd.h
+++ b/xlators/mgmt/glusterd/src/glusterd.h
@@ -45,7 +45,7 @@
 #include "glusterd1-xdr.h"
 #include "protocol-common.h"
 #include "glusterd-pmap.h"
-
+#include "cli1-xdr.h"
 
 #define GLUSTERD_MAX_VOLUME_NAME        1000
 #define DEFAULT_LOG_FILE_DIRECTORY      DATADIR "/log/glusterfs"
@@ -132,6 +132,7 @@ struct glusterd_brickinfo {
         gf_brick_status_t status;
         struct rpc_clnt *rpc;
         gf_timer_t *timer;
+        int decommissioned;
 };
 
 typedef struct glusterd_brickinfo glusterd_brickinfo_t;
@@ -142,16 +143,11 @@ struct gf_defrag_brickinfo_ {
         int   size;
 };
 
-typedef enum gf_defrag_status_ {
-        GF_DEFRAG_STATUS_NOT_STARTED,
-        GF_DEFRAG_STATUS_LAYOUT_FIX_STARTED,
-        GF_DEFRAG_STATUS_MIGRATE_DATA_STARTED,
-        GF_DEFRAG_STATUS_STOPED,
-        GF_DEFRAG_STATUS_COMPLETE,
-        GF_DEFRAG_STATUS_FAILED,
-        GF_DEFRAG_STATUS_LAYOUT_FIX_COMPLETE,
-        GF_DEFRAG_STATUS_MIGRATE_DATA_COMPLETE,
-} gf_defrag_status_t;
+struct glusterd_volinfo_;
+typedef struct glusterd_volinfo_ glusterd_volinfo_t;
+
+typedef int (*defrag_cbk_fn_t) (glusterd_volinfo_t *volinfo,
+                                gf_defrag_status_t status);
 
 struct glusterd_defrag_info_ {
         uint64_t                     total_files;
@@ -163,6 +159,8 @@ struct glusterd_defrag_info_ {
         char                         mount[1024];
         char                         databuf[131072];
         struct gf_defrag_brickinfo_ *bricks; /* volinfo->brick_count */
+
+        defrag_cbk_fn_t              cbk_fn;
 };
 
 
@@ -219,9 +217,10 @@ struct glusterd_volinfo_ {
         char                    *logdir;
 
         dict_t                  *gsync_slaves;
-};
 
-typedef struct glusterd_volinfo_ glusterd_volinfo_t;
+        int                      decommission_in_progress;
+        xlator_t                *xl;
+};
 
 typedef struct glusterd_pending_node_ {
         void   *node;
@@ -540,6 +539,8 @@ int glusterd_handle_cli_start_volume (rpcsvc_request_t *req);
 int glusterd_handle_cli_stop_volume (rpcsvc_request_t *req);
 int glusterd_handle_cli_delete_volume (rpcsvc_request_t *req);
 
+int glusterd_handle_defrag_start (glusterd_volinfo_t *volinfo, char *op_errstr,
+                                  size_t len, int cmd, defrag_cbk_fn_t cbk);
 
 /* op-sm functions */
 int glusterd_op_stage_gsync_set (dict_t *dict, char **op_errstr);
@@ -565,9 +566,9 @@ int glusterd_op_stop_volume (dict_t *dict);
 int glusterd_op_delete_volume (dict_t *dict);
 
 int glusterd_op_add_brick (dict_t *dict, char **op_errstr);
-int glusterd_op_remove_brick (dict_t *dict);
+int glusterd_op_remove_brick (dict_t *dict, char **op_errstr);
 int glusterd_op_stage_add_brick (dict_t *dict, char **op_errstr);
-int glusterd_op_stage_remove_brick (dict_t *dict);
+int glusterd_op_stage_remove_brick (dict_t *dict, char **op_errstr);
 
 int glusterd_op_stage_rebalance (dict_t *dict, char **op_errstr);
 int glusterd_op_rebalance (dict_t *dict, char **op_errstr, dict_t *rsp_dict);
@@ -575,7 +576,8 @@ int glusterd_op_rebalance (dict_t *dict, char **op_errstr, dict_t *rsp_dict);
 
 /* misc */
 void glusterd_do_replace_brick (void *data);
-int glusterd_op_perform_remove_brick (glusterd_volinfo_t  *volinfo, char *brick);
+int glusterd_op_perform_remove_brick (glusterd_volinfo_t  *volinfo, char *brick,
+                                      int force, int *need_migrate);
 int glusterd_op_stop_volume_args_get (dict_t *dict, char** volname, int *flags);