dht: Implement ipc fop

ipc is used by md-cache to communicate the list of xattrs that
it is caching, to the upcall xlator. Hence implement this in
dht, such that it winds to all the bricks if the ipc op is
GF_IPC_MDC_TARGET_UPCALL. The ips should not fail if any of
the bricks is down, as md-cache will replay the ipc late when
the brick comes back up.

Change-Id: Ica551a550c04cbb1240c0d211fe831c2e5eb6017
BUG: 1211863
Signed-off-by: Poornima G <pgurusid@redhat.com>
Reviewed-on: http://review.gluster.org/15225
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Smoke: Gluster Build System <jenkins@build.gluster.org>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
Reviewed-by: Raghavendra G <rgowdapp@redhat.com>

3 files changed, 87 insertions, 0 deletions

diff --git a/xlators/cluster/dht/src/dht-common.c b/xlators/cluster/dht/src/dht-common.c
index f3499ed6d0..a76ef59706 100644
--- a/xlators/cluster/dht/src/dht-common.c
+++ b/xlators/cluster/dht/src/dht-common.c
@@ -8488,6 +8488,90 @@ err:
 }
 
 
+int32_t
+dht_ipc_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
+             int32_t op_ret, int32_t op_errno, dict_t *xdata)
+{
+        dht_local_t  *local                   = NULL;
+        int           this_call_cnt           = 0;
+        dht_layout_t *layout                  = NULL;
+        int           ret                     = -1;
+
+        GF_VALIDATE_OR_GOTO ("dht", frame, out);
+        GF_VALIDATE_OR_GOTO ("dht", this, out);
+        GF_VALIDATE_OR_GOTO ("dht", frame->local, out);
+
+        local = frame->local;
+
+        LOCK (&frame->lock);
+        {
+                if (op_ret < 0 && op_errno != ENOTCONN) {
+                        local->op_errno = op_errno;
+                        goto unlock;
+                }
+                local->op_ret = 0;
+        }
+unlock:
+        UNLOCK (&frame->lock);
+
+        this_call_cnt = dht_frame_return (frame);
+        if (is_last_call (this_call_cnt)) {
+                DHT_STACK_UNWIND (ipc, frame, local->op_ret, local->op_errno,
+                                  NULL);
+        }
+
+out:
+        return 0;
+}
+
+
+int32_t
+dht_ipc (call_frame_t *frame, xlator_t *this, int32_t op, dict_t *xdata)
+{
+        dht_local_t  *local    = NULL;
+        int           op_errno = EINVAL;
+        dht_conf_t   *conf     = NULL;
+        int           call_cnt = 0;
+        int           i        = 0;
+
+        VALIDATE_OR_GOTO (frame, err);
+        VALIDATE_OR_GOTO (this, err);
+
+        if (op != GF_IPC_TARGET_UPCALL)
+                goto wind_default;
+
+        VALIDATE_OR_GOTO (this->private, err);
+        conf = this->private;
+
+        local = dht_local_init (frame, NULL, NULL, GF_FOP_IPC);
+        if (!local) {
+                op_errno = ENOMEM;
+                goto err;
+        }
+
+        call_cnt        = conf->subvolume_cnt;
+        local->call_cnt = call_cnt;
+
+        for (i = 0; i < call_cnt; i++) {
+                STACK_WIND (frame, dht_ipc_cbk, conf->subvolumes[i],
+                            conf->subvolumes[i]->fops->ipc, op, xdata);
+        }
+
+        return 0;
+
+err:
+        op_errno = (op_errno == -1) ? errno : op_errno;
+        DHT_STACK_UNWIND (ipc, frame, -1, op_errno, NULL);
+
+        return 0;
+
+wind_default:
+        STACK_WIND (frame, default_ipc_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->ipc, op, xdata);
+        return 0;
+}
+
+
 int
 dht_forget (xlator_t *this, inode_t *inode)
 {
diff --git a/xlators/cluster/dht/src/dht-common.h b/xlators/cluster/dht/src/dht-common.h
index 760a86cccd..3717a68273 100644
--- a/xlators/cluster/dht/src/dht-common.h
+++ b/xlators/cluster/dht/src/dht-common.h
@@ -1028,6 +1028,8 @@ int32_t dht_discard(call_frame_t *frame, xlator_t *this, fd_t *fd,
 		    off_t offset, size_t len, dict_t *xdata);
 int32_t dht_zerofill(call_frame_t *frame, xlator_t *this, fd_t *fd,
                     off_t offset, off_t len, dict_t *xdata);
+int32_t dht_ipc (call_frame_t *frame, xlator_t *this, int32_t op,
+                 dict_t *xdata);
 
 int
 dht_set_subvol_range(xlator_t *this);
diff --git a/xlators/cluster/dht/src/dht.c b/xlators/cluster/dht/src/dht.c
index afdfd5c80e..90962636d1 100644
--- a/xlators/cluster/dht/src/dht.c
+++ b/xlators/cluster/dht/src/dht.c
@@ -20,6 +20,7 @@ class_methods_t class_methods = {
 };
 
 struct xlator_fops fops = {
+        .ipc         = dht_ipc,
         .lookup      = dht_lookup,
         .mknod       = dht_mknod,
         .create      = dht_create,