Introduce new extended attribute: node-uuid

Request for trusted.glusterfs.node-uuid returns pathinfo
like string but containing the UUID of glusterd instead
of the backend path for the requested file. This info
is benificial for tasks like parallel rebalance that will
make use of the UUID for data locality.

Change-Id: I766a09cc4a5f63aebd11c73107924a1b29242dcf
BUG: 772610
Signed-off-by: Venky Shankar <vshankar@redhat.com>
Reviewed-on: http://review.gluster.com/2614
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Shishir Gowda <shishirng@gluster.com>
Reviewed-by: Vijay Bellur <vijay@gluster.com>

1 files changed, 104 insertions, 35 deletions

diff --git a/xlators/cluster/afr/src/afr-inode-read.c b/xlators/cluster/afr/src/afr-inode-read.c
index 499804e6..c4619270 100644
--- a/xlators/cluster/afr/src/afr-inode-read.c
+++ b/xlators/cluster/afr/src/afr-inode-read.c
@@ -726,24 +726,73 @@ unlock:
         return ret;
 }
 
+/**
+ * node-uuid cbk uses next child querying mechanism
+ */
+int32_t
+afr_getxattr_node_uuid_cbk (call_frame_t *frame, void *cookie,
+                            xlator_t *this, int32_t op_ret, int32_t op_errno,
+                            dict_t *dict)
+{
+        afr_private_t  *priv            = NULL;
+        afr_local_t    *local           = NULL;
+        xlator_t      **children        = NULL;
+        int             unwind          = 1;
+        int             curr_call_child = 0;
+
+        priv = this->private;
+        children = priv->children;
+
+        local = frame->local;
+
+        if (op_ret == -1) { /** query the _next_ child */
+
+                /**
+                 * _current_ becomes _next_
+                 * If done with all childs and yet no success; give up !
+                 */
+                curr_call_child = (int) ((long)cookie);
+                if (++curr_call_child == priv->child_count)
+                        goto unwind;
+
+                gf_log (this->name, GF_LOG_WARNING,
+                        "op_ret (-1): Re-querying afr-child (%d/%d)",
+                        curr_call_child, priv->child_count);
+
+                unwind = 0;
+                STACK_WIND_COOKIE (frame, afr_getxattr_node_uuid_cbk,
+                                   (void *) (long) curr_call_child,
+                                   children[curr_call_child],
+                                   children[curr_call_child]->fops->getxattr,
+                                   &local->loc,
+                                   local->cont.getxattr.name);
+        }
+
+ unwind:
+        if (unwind)
+                AFR_STACK_UNWIND (getxattr, frame, op_ret, op_errno, dict);
+
+        return 0;
+}
+
 int32_t
 afr_getxattr_pathinfo_cbk (call_frame_t *frame, void *cookie,
                            xlator_t *this, int32_t op_ret, int32_t op_errno,
                            dict_t *dict)
 {
-        afr_local_t *local             = NULL;
-        int32_t      callcnt           = 0;
-        int          ret               = 0;
-        char        *pathinfo          = NULL;
-        char        *pathinfo_serz     = NULL;
-        char        pathinfo_cky[1024] = {0,};
-        dict_t      *xattr             = NULL;
-        long         cky               = 0;
-        int32_t      padding           = 0;
-        int32_t      tlen              = 0;
+        afr_local_t *local          = NULL;
+        int32_t      callcnt        = 0;
+        int          ret            = 0;
+        char        *xattr          = NULL;
+        char        *xattr_serz     = NULL;
+        char        xattr_cky[1024] = {0,};
+        dict_t      *nxattr         = NULL;
+        long         cky            = 0;
+        int32_t      padding        = 0;
+        int32_t      tlen           = 0;
 
         if (!frame || !frame->local || !this) {
-                gf_log (this->name, GF_LOG_ERROR, "possible NULL deref");
+                gf_log ("", GF_LOG_ERROR, "possible NULL deref");
                 goto out;
         }
 
@@ -761,70 +810,80 @@ afr_getxattr_pathinfo_cbk (call_frame_t *frame, void *cookie,
                                 local->dict = dict_new ();
 
                         if (local->dict) {
-                                ret = dict_get_str (dict, GF_XATTR_PATHINFO_KEY, &pathinfo);
+                                ret = dict_get_str (dict,
+                                                    local->cont.getxattr.name,
+                                                    &xattr);
                                 if (ret)
                                         goto out;
 
-                                pathinfo = gf_strdup (pathinfo);
+                                xattr = gf_strdup (xattr);
 
-                                snprintf (pathinfo_cky, 1024, "%s-%ld", GF_XATTR_PATHINFO_KEY, cky);
-                                ret = dict_set_dynstr (local->dict, pathinfo_cky, pathinfo);
+                                (void)snprintf (xattr_cky, 1024, "%s-%ld",
+                                                local->cont.getxattr.name, cky);
+                                ret = dict_set_dynstr (local->dict,
+                                                       xattr_cky, xattr);
                                 if (ret) {
-                                        gf_log (this->name, GF_LOG_ERROR, "Cannot set pathinfo cookie key");
+                                        gf_log (this->name, GF_LOG_ERROR,
+                                                "Cannot set xattr cookie key");
                                         goto out;
                                 }
 
-                                local->cont.getxattr.pathinfo_len += strlen (pathinfo) + 1;
+                                local->cont.getxattr.xattr_len += strlen (xattr) + 1;
                         }
                 }
  out:
         UNLOCK (&frame->lock);
 
         if (!callcnt) {
-                if (!local->cont.getxattr.pathinfo_len)
+                if (!local->cont.getxattr.xattr_len)
                         goto unwind;
 
-                xattr = dict_new ();
-                if (!xattr)
+                nxattr = dict_new ();
+                if (!nxattr)
                         goto unwind;
 
                 /* extra bytes for decorations (brackets and <>'s) */
-                padding = strlen (this->name) + strlen (AFR_PATHINFO_HEADER) + 4;
-                local->cont.getxattr.pathinfo_len += (padding + 2);
+                padding += strlen (this->name) + strlen (AFR_PATHINFO_HEADER) + 4;
+                local->cont.getxattr.xattr_len += (padding + 2);
 
-                pathinfo_serz = GF_CALLOC (local->cont.getxattr.pathinfo_len, sizeof (char),
-                                           gf_common_mt_char);
+                xattr_serz = GF_CALLOC (local->cont.getxattr.xattr_len,
+                                        sizeof (char), gf_common_mt_char);
 
-                if (!pathinfo_serz)
+                if (!xattr_serz)
                         goto unwind;
 
                 /* the xlator info */
-                sprintf (pathinfo_serz, "(<"AFR_PATHINFO_HEADER"%s> ", this->name);
+                (void) sprintf (xattr_serz, "(<"AFR_PATHINFO_HEADER"%s> ",
+                                this->name);
 
                 /* actual series of pathinfo */
-                ret = dict_serialize_value_with_delim (local->dict, pathinfo_serz + strlen (pathinfo_serz),
+                ret = dict_serialize_value_with_delim (local->dict,
+                                                       xattr_serz + strlen (xattr_serz),
                                                        &tlen, ' ');
                 if (ret) {
-                        gf_log (this->name, GF_LOG_ERROR, "Error serializing dictionary");
+                        gf_log (this->name, GF_LOG_ERROR, "Error serializing"
+                                " dictionary");
                         goto unwind;
                 }
 
                 /* closing part */
-                *(pathinfo_serz + padding + tlen) = ')';
-                *(pathinfo_serz + padding + tlen + 1) = '\0';
+                *(xattr_serz + padding + tlen) = ')';
+                *(xattr_serz + padding + tlen + 1) = '\0';
 
-                ret = dict_set_dynstr (xattr, GF_XATTR_PATHINFO_KEY, pathinfo_serz);
+                ret = dict_set_dynstr (nxattr, local->cont.getxattr.name,
+                                       xattr_serz);
                 if (ret)
-                        gf_log (this->name, GF_LOG_ERROR, "Cannot set pathinfo key in dict");
+                        gf_log (this->name, GF_LOG_ERROR, "Cannot set pathinfo"
+                                " key in dict");
 
         unwind:
-                AFR_STACK_UNWIND (getxattr, frame, op_ret, op_errno, xattr);
+                AFR_STACK_UNWIND (getxattr, frame, op_ret, op_errno, nxattr);
 
                 if (local->dict)
                         dict_unref (local->dict);
 
-                if (xattr)
-                        dict_unref (xattr);
+                if (nxattr)
+                        dict_unref (nxattr);
         }
 
         return ret;
@@ -964,6 +1023,16 @@ afr_getxattr (call_frame_t *frame, xlator_t *this,
                         return 0;
                 }
 
+                if (XATTR_IS_NODE_UUID (name)) {
+                        i = 0;
+                        STACK_WIND_COOKIE (frame, afr_getxattr_node_uuid_cbk,
+                                           (void *) (long) i,
+                                           children[i],
+                                           children[i]->fops->getxattr,
+                                           loc, name);
+                        return 0;
+                }
+
                 if (*priv->vol_uuid) {
                         if ((match_uuid_local (name, priv->vol_uuid) == 0)
                             && (-1 == frame->root->pid)) {