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>

2 files changed, 113 insertions, 58 deletions

diff --git a/xlators/cluster/stripe/src/stripe.c b/xlators/cluster/stripe/src/stripe.c
index 62a28d71f52..c44bac57525 100644
--- a/xlators/cluster/stripe/src/stripe.c
+++ b/xlators/cluster/stripe/src/stripe.c
@@ -4567,7 +4567,7 @@ out:
 }
 
 int32_t
-stripe_pathinfo_aggregate (char *buffer, stripe_local_t *local, int32_t *total)
+stripe_xattr_aggregate (char *buffer, stripe_local_t *local, int32_t *total)
 {
         int32_t              i     = 0;
         int32_t              ret   = -1;
@@ -4582,10 +4582,10 @@ stripe_pathinfo_aggregate (char *buffer, stripe_local_t *local, int32_t *total)
 
         for (i = 0; i < local->nallocs; i++) {
                 xattr = local->xattr_list + i;
-                len = xattr->pathinfo_len;
+                len = xattr->xattr_len;
 
-                if (len && xattr && xattr->pathinfo) {
-                        memcpy (buffer, xattr->pathinfo, len);
+                if (len && xattr && xattr->xattr_value) {
+                        memcpy (buffer, xattr->xattr_value, len);
                         buffer += len;
                         *buffer++ = ' ';
                 }
@@ -4601,7 +4601,7 @@ stripe_pathinfo_aggregate (char *buffer, stripe_local_t *local, int32_t *total)
 }
 
 int32_t
-stripe_free_pathinfo_str (stripe_local_t *local)
+stripe_free_xattr_str (stripe_local_t *local)
 {
         int32_t              i     = 0;
         int32_t              ret   = -1;
@@ -4613,8 +4613,8 @@ stripe_free_pathinfo_str (stripe_local_t *local)
         for (i = 0; i < local->nallocs; i++) {
                 xattr = local->xattr_list + i;
 
-                if (xattr && xattr->pathinfo)
-                        GF_FREE (xattr->pathinfo);
+                if (xattr && xattr->xattr_value)
+                        GF_FREE (xattr->xattr_value);
         }
 
         ret = 0;
@@ -4623,18 +4623,64 @@ stripe_free_pathinfo_str (stripe_local_t *local)
 }
 
 int32_t
-stripe_getxattr_pathinfo_cbk (call_frame_t *frame, void *cookie,
+stripe_fill_pathinfo_xattr (xlator_t *this, stripe_local_t *local,
+                            char **xattr_serz)
+{
+        int      ret             = -1;
+        int32_t  padding         = 0;
+        int32_t  tlen            = 0;
+        char stripe_size_str[20] = {0,};
+        char    *pathinfo_serz   = NULL;
+
+        if (!local) {
+                gf_log (this->name, GF_LOG_ERROR, "Possible NULL deref");
+                goto out;
+        }
+
+        (void) snprintf (stripe_size_str, 20, "%ld",
+                         (local->fctx) ? local->fctx->stripe_size : 0);
+
+        /* extra bytes for decorations (brackets and <>'s) */
+        padding = strlen (this->name) + strlen (STRIPE_PATHINFO_HEADER)
+                + strlen (stripe_size_str) + 7;
+        local->xattr_total_len += (padding + 2);
+
+        pathinfo_serz = GF_CALLOC (local->xattr_total_len, sizeof (char),
+                                   gf_common_mt_char);
+        if (!pathinfo_serz)
+                goto out;
+
+        /* xlator info */
+        (void) sprintf (pathinfo_serz, "(<"STRIPE_PATHINFO_HEADER"%s:[%s]> ",
+                        this->name, stripe_size_str);
+
+        ret = stripe_xattr_aggregate (pathinfo_serz + padding, local, &tlen);
+        if (ret) {
+                gf_log (this->name, GF_LOG_ERROR,
+                        "Cannot aggregate pathinfo list");
+                goto out;
+        }
+
+        *(pathinfo_serz + padding + tlen) = ')';
+        *(pathinfo_serz + padding + tlen + 1) = '\0';
+
+        *xattr_serz = pathinfo_serz;
+
+        ret = 0;
+ out:
+        return ret;
+}
+
+int32_t
+stripe_vgetxattr_cbk (call_frame_t *frame, void *cookie,
                              xlator_t *this, int32_t op_ret, int32_t op_errno,
                              dict_t *dict) {
         stripe_local_t      *local         = NULL;
         int32_t              callcnt       = 0;
         int32_t              ret           = -1;
         long                 cky           = 0;
-        char                *pathinfo      = NULL;
-        char                *pathinfo_serz = NULL;
-        int32_t              padding       = 0;
-        int32_t              tlen          = 0;
-        char stripe_size_str[20]           = {0,};
+        char                *xattr_val     = NULL;
+        char                *xattr_serz    = NULL;
         stripe_xattr_sort_t *xattr         = NULL;
         dict_t              *stripe_xattr  = NULL;
 
@@ -4646,6 +4692,11 @@ stripe_getxattr_pathinfo_cbk (call_frame_t *frame, void *cookie,
         local = frame->local;
         cky = (long) cookie;
 
+        if (!local->xsel) {
+                gf_log (this->name, GF_LOG_ERROR, "Empty xattr in cbk");
+                return ret;
+        }
+
         LOCK (&frame->lock);
         {
                 callcnt = --local->wind_count;
@@ -4654,23 +4705,24 @@ stripe_getxattr_pathinfo_cbk (call_frame_t *frame, void *cookie,
                         goto out;
 
                 if (!local->xattr_list)
-                        local->xattr_list = (stripe_xattr_sort_t *) GF_CALLOC (local->nallocs,
-                                                                               sizeof (stripe_xattr_sort_t),
-                                                                               gf_stripe_mt_xattr_sort_t);
+                        local->xattr_list = (stripe_xattr_sort_t *)
+                                GF_CALLOC (local->nallocs,
+                                           sizeof (stripe_xattr_sort_t),
+                                           gf_stripe_mt_xattr_sort_t);
 
                 if (local->xattr_list) {
-                        ret = dict_get_str (dict, GF_XATTR_PATHINFO_KEY, &pathinfo);
+                        ret = dict_get_str (dict, local->xsel, &xattr_val);
                         if (ret)
                                 goto out;
 
                         xattr = local->xattr_list + (int32_t) cky;
 
-                        pathinfo = gf_strdup (pathinfo);
+                        xattr_val = gf_strdup (xattr_val);
                         xattr->pos = cky;
-                        xattr->pathinfo = pathinfo;
-                        xattr->pathinfo_len = strlen (pathinfo);
+                        xattr->xattr_value = xattr_val;
+                        xattr->xattr_len = strlen (xattr_val);
 
-                        local->xattr_total_len += strlen (pathinfo) + 1;
+                        local->xattr_total_len += xattr->xattr_len + 1;
                 }
         }
  out:
@@ -4684,38 +4736,29 @@ stripe_getxattr_pathinfo_cbk (call_frame_t *frame, void *cookie,
                 if (!stripe_xattr)
                         goto unwind;
 
-                snprintf (stripe_size_str, 20, "%ld", local->stripe_size);
-
-                /* extra bytes for decorations (brackets and <>'s) */
-                padding = strlen (this->name) + strlen (STRIPE_PATHINFO_HEADER)
-                        + strlen (stripe_size_str) + 7;
-                local->xattr_total_len += (padding + 2);
-
-                pathinfo_serz = GF_CALLOC (local->xattr_total_len, sizeof (char),
-                                           gf_common_mt_char);
-                if (!pathinfo_serz)
-                        goto unwind;
-
-                /* xlator info */
-                sprintf (pathinfo_serz, "(<"STRIPE_PATHINFO_HEADER"%s:[%s]> ", this->name, stripe_size_str);
-
-                ret = stripe_pathinfo_aggregate (pathinfo_serz + padding, local, &tlen);
-                if (ret) {
-                        gf_log (this->name, GF_LOG_ERROR, "Cannot aggregate pathinfo list");
+                /* select filler based on ->xsel */
+                if (XATTR_IS_PATHINFO (local->xsel))
+                        ret = stripe_fill_pathinfo_xattr (this, local,
+                                                          &xattr_serz);
+                else {
+                        gf_log (this->name, GF_LOG_WARNING,
+                                "Unknown xattr in xattr request");
                         goto unwind;
                 }
 
-                *(pathinfo_serz + padding + tlen) = ')';
-                *(pathinfo_serz + padding + tlen + 1) = '\0';
-
-                ret = dict_set_dynstr (stripe_xattr, GF_XATTR_PATHINFO_KEY, pathinfo_serz);
-                if (ret)
-                        gf_log (this->name, GF_LOG_ERROR, "Cannot set pathinfo key in dict");
+                if (!ret) {
+                        ret = dict_set_dynstr (stripe_xattr, local->xsel,
+                                               xattr_serz);
+                        if (ret)
+                                gf_log (this->name, GF_LOG_ERROR,
+                                        "Can't set %s key in dict", local->xsel);
+                }
 
         unwind:
-                STRIPE_STACK_UNWIND (getxattr, frame, op_ret, op_errno, stripe_xattr);
+                STRIPE_STACK_UNWIND (getxattr, frame, op_ret, op_errno,
+                                     stripe_xattr);
 
-                ret = stripe_free_pathinfo_str (local);
+                ret = stripe_free_xattr_str (local);
 
                 if (local->xattr_list)
                         GF_FREE (local->xattr_list);
@@ -4797,19 +4840,30 @@ stripe_getxattr (call_frame_t *frame, xlator_t *this,
                 return 0;
         }
 
-        if (name && (strncmp (name, GF_XATTR_PATHINFO_KEY,
-                              strlen (GF_XATTR_PATHINFO_KEY)) == 0)) {
-                ret = inode_ctx_get (loc->inode, this,
-                                     (uint64_t *) &local->stripe_size);
-                if (ret)
-                        gf_log (this->name, GF_LOG_ERROR,
-                                "stripe size unavailable from inode ctx - relying"
-                                " on pathinfo could lead to wrong results");
+        if (name &&
+            ((strncmp (name, GF_XATTR_PATHINFO_KEY,
+                       strlen (GF_XATTR_PATHINFO_KEY)) == 0))) {
+                if (IA_ISREG (loc->inode->ia_type)) {
+                        ret = inode_ctx_get (loc->inode, this,
+                                             (uint64_t *) &local->fctx);
+                        if (ret)
+                                gf_log (this->name, GF_LOG_ERROR,
+                                        "stripe size unavailable from fctx"
+                                        " relying on pathinfo could lead to"
+                                        " wrong results");
+                }
+
                 local->nallocs = local->wind_count = priv->child_count;
+                (void) strncpy (local->xsel, name, strlen (name));
 
+                /**
+                 * for xattrs that need info from all childs, fill ->xsel
+                 * as above and call the filler function in cbk based on
+                 * it
+                 */
                 for (i = 0, trav = this->children; i < priv->child_count; i++,
                      trav = trav->next) {
-                        STACK_WIND_COOKIE (frame, stripe_getxattr_pathinfo_cbk,
+                        STACK_WIND_COOKIE (frame, stripe_vgetxattr_cbk,
                                            (void *) (long) i, trav->xlator,
                                            trav->xlator->fops->getxattr,
                                            loc, name);
diff --git a/xlators/cluster/stripe/src/stripe.h b/xlators/cluster/stripe/src/stripe.h
index e78583996d2..580920a1b30 100644
--- a/xlators/cluster/stripe/src/stripe.h
+++ b/xlators/cluster/stripe/src/stripe.h
@@ -66,8 +66,8 @@
 
 typedef struct stripe_xattr_sort {
         int32_t  pos;
-        int32_t  pathinfo_len;
-        char    *pathinfo;
+        int32_t  xattr_len;
+        char    *xattr_value;
 } stripe_xattr_sort_t;
 
 /**
@@ -178,6 +178,7 @@ struct stripe_local {
         stripe_xattr_sort_t *xattr_list;
         int32_t              xattr_total_len;
         int32_t              nallocs;
+        char xsel[256];
 
         struct marker_str    marker;