dht: At places needed use STACK_WIND_COOKIE

Issue:
frame has a void * cookie pointer.
In case of STACK_WIND_COOKIE frame->cookie is assigned
to what is sent by the caller.
In case of STACK_WIND frame->cookie is assigned to point
point to the frame itself.

For ease of coding, at many places, the cookie in the cbk
is used to get the pointer to the next xl. This is
inconsistent when STACK_WIND_TAIL comes into picture.

Eg: dht_setxattr () {
    for (i = 0 ; i < conf->subvolume_cnt ; i++) {
       STACK_WIND (..dht_checking_pathinfo_cbk,
                   conf->subvolumes[i] ..);
    }

    dht_checking_pathinfo_cbk (...void *cookie...) {
        prev = cookie;
        ...
        for (i = 0; i < conf->subvolume_cnt; i++) {
            if (conf->subvolumes[i] == prev->this) {
                 ...
            }
        }
    }

    Consider the below graph:
    dht (parent)
    readdir-ahead  => Doesn't define setxattr and uses STACK_WIND_TAIL
    protocol-client

    With this graph, when dht_checking_pathinfo_cbk is called,
    cookie will have frame pointing to protocol-client.
    i.e. prev->this will be protocol-client. But dht was expecting
    it to be readdir-ahead as it has stored in conf->subvolumes[i]

Solution:
    Hence, as a thumb rule, if cbk is using cookie, then we explicitly
    call STACK_WIND_COOKIE.

Change-Id: I83aea1e24c809c5a91a0db7283e908e125471bd4
BUG: 1401812
Signed-off-by: Poornima G <pgurusid@redhat.com>
Reviewed-on: http://review.gluster.org/16039
Reviewed-by: Raghavendra G <rgowdapp@redhat.com>
Smoke: Gluster Build System <jenkins@build.gluster.org>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>

1 files changed, 38 insertions, 35 deletions

diff --git a/xlators/cluster/dht/src/switch.c b/xlators/cluster/dht/src/switch.c
index f1e9a399442..9795ff4af4d 100644
--- a/xlators/cluster/dht/src/switch.c
+++ b/xlators/cluster/dht/src/switch.c
@@ -111,7 +111,7 @@ switch_local_lookup_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
         dht_local_t  *local       = NULL;
         loc_t        *loc         = NULL;
         int           i           = 0;
-        call_frame_t *prev        = NULL;
+        xlator_t     *prev        = NULL;
         int           call_cnt    = 0;
         int           ret         = 0;
 
@@ -139,12 +139,12 @@ switch_local_lookup_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
         if (!is_dir && !is_linkfile) {
                 /* non-directory and not a linkfile */
 
-                ret = dht_layout_preset (this, prev->this, inode);
+                ret = dht_layout_preset (this, prev, inode);
                 if (ret < 0) {
                         gf_msg_debug (this->name, 0,
                                       "could not set pre-set layout "
                                       "for subvol %s",
-                                      prev->this->name);
+                                      prev->name);
                         op_ret   = -1;
                         op_errno = EINVAL;
                         goto err;
@@ -173,10 +173,11 @@ switch_local_lookup_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
                 }
 
                 for (i = 0; i < call_cnt; i++) {
-                        STACK_WIND (frame, dht_lookup_dir_cbk,
-                                    conf->subvolumes[i],
-                                    conf->subvolumes[i]->fops->lookup,
-                                    &local->loc, local->xattr_req);
+                        STACK_WIND_COOKIE (frame, dht_lookup_dir_cbk,
+                                           conf->subvolumes[i],
+                                           conf->subvolumes[i],
+                                           conf->subvolumes[i]->fops->lookup,
+                                           &local->loc, local->xattr_req);
                 }
         }
 
@@ -191,9 +192,9 @@ switch_local_lookup_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
                         return 0;
                 }
 
-                STACK_WIND (frame, dht_lookup_linkfile_cbk,
-                            subvol, subvol->fops->lookup,
-                            &local->loc, local->xattr_req);
+                STACK_WIND_COOKIE (frame, dht_lookup_linkfile_cbk, subvol,
+                                   subvol, subvol->fops->lookup,
+                                   &local->loc, local->xattr_req);
         }
 
         return 0;
@@ -208,9 +209,10 @@ out:
                 return 0;
         }
 
-        STACK_WIND (frame, dht_lookup_cbk,
-                    local->hashed_subvol, local->hashed_subvol->fops->lookup,
-                    &local->loc, local->xattr_req);
+        STACK_WIND_COOKIE (frame, dht_lookup_cbk, local->hashed_subvol,
+                           local->hashed_subvol,
+                           local->hashed_subvol->fops->lookup,
+                           &local->loc, local->xattr_req);
 
         return 0;
 
@@ -298,9 +300,9 @@ switch_lookup (call_frame_t *frame, xlator_t *this,
                 for (i = 0; i < layout->cnt; i++) {
                         subvol = layout->list[i].xlator;
 
-                        STACK_WIND (frame, dht_revalidate_cbk,
-                                    subvol, subvol->fops->lookup,
-                                    loc, local->xattr_req);
+                        STACK_WIND_COOKIE (frame, dht_revalidate_cbk, subvol,
+                                           subvol, subvol->fops->lookup,
+                                           loc, local->xattr_req);
 
                         if (!--call_cnt)
                                 break;
@@ -339,10 +341,11 @@ switch_lookup (call_frame_t *frame, xlator_t *this,
                         }
 
                         for (i = 0; i < call_cnt; i++) {
-                                STACK_WIND (frame, dht_lookup_dir_cbk,
-                                            conf->subvolumes[i],
-                                            conf->subvolumes[i]->fops->lookup,
-                                            &local->loc, local->xattr_req);
+                                STACK_WIND_COOKIE (frame, dht_lookup_dir_cbk,
+                                                   conf->subvolumes[i],
+                                                   conf->subvolumes[i],
+                                                   conf->subvolumes[i]->fops->lookup,
+                                                   &local->loc, local->xattr_req);
                         }
                         return 0;
                 }
@@ -351,15 +354,15 @@ switch_lookup (call_frame_t *frame, xlator_t *this,
                 cached_subvol = get_switch_matching_subvol (loc->path, conf,
                                                             hashed_subvol);
                 if (cached_subvol == hashed_subvol) {
-                        STACK_WIND (frame, dht_lookup_cbk,
-                                    hashed_subvol,
-                                    hashed_subvol->fops->lookup,
-                                    loc, local->xattr_req);
+                        STACK_WIND_COOKIE (frame, dht_lookup_cbk, hashed_subvol,
+                                           hashed_subvol,
+                                           hashed_subvol->fops->lookup,
+                                           loc, local->xattr_req);
                 } else {
-                        STACK_WIND (frame, switch_local_lookup_cbk,
-                                    cached_subvol,
-                                    cached_subvol->fops->lookup,
-                                    loc, local->xattr_req);
+                        STACK_WIND_COOKIE (frame, switch_local_lookup_cbk,
+                                           cached_subvol, cached_subvol,
+                                           cached_subvol->fops->lookup,
+                                           loc, local->xattr_req);
                 }
         }
 
@@ -386,10 +389,10 @@ switch_create_linkfile_create_cbk (call_frame_t *frame, void *cookie,
         if (op_ret == -1)
                 goto err;
 
-        STACK_WIND (frame, dht_create_cbk,
-                    local->cached_subvol, local->cached_subvol->fops->create,
-                    &local->loc, local->flags, local->mode, local->umask,
-                    local->fd, local->params);
+        STACK_WIND_COOKIE (frame, dht_create_cbk, local->cached_subvol,
+                           local->cached_subvol, local->cached_subvol->fops->create,
+                           &local->loc, local->flags, local->mode, local->umask,
+                           local->fd, local->params);
 
         return 0;
 
@@ -454,9 +457,9 @@ switch_create (call_frame_t *frame, xlator_t *this,
         gf_msg_trace (this->name, 0,
                       "creating %s on %s", loc->path, subvol->name);
 
-        STACK_WIND (frame, dht_create_cbk,
-                    subvol, subvol->fops->create,
-                    loc, flags, mode, umask, fd, params);
+        STACK_WIND_COOKIE (frame, dht_create_cbk, subvol, subvol,
+                           subvol->fops->create, loc, flags, mode, umask, fd,
+                           params);
 
         return 0;