afr: heal metadata in discover code path

******************************************************
Backport of: https://review.gluster.org/18202
Also added loc_is_nameless() to libglusterfs since the patch that
introduced it in master was not backported to release-3.10.

Note: 18202 is a squash of  17850 and 18187 in master.
******************************************************

During graph switch, if fuse sends nameless (gfid) lookups, afr takes
the discover code path to serve it. If there are pending metadata heals,
they do not happen unless an inode refresh happens as a part of
discover (which is not guaranteed to happen always).

This patch fixes it by attempting metadata heal as a part of discover,
just like how it is done in lookup code path.

Change-Id: I87c493045b9225741cad173bf3f645848697032e
BUG: 1492010
Signed-off-by: Ravishankar N <ravishankar@redhat.com>
Reviewed-on: https://review.gluster.org/18304
Smoke: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Shyamsundar Ranganathan <srangana@redhat.com>

4 files changed, 60 insertions, 17 deletions

diff --git a/libglusterfs/src/xlator.c b/libglusterfs/src/xlator.c
index 0d09b3fbc82..16da028dc09 100644
--- a/libglusterfs/src/xlator.c
+++ b/libglusterfs/src/xlator.c
@@ -1025,6 +1025,19 @@ out:
         return ret;
 }
 
+gf_boolean_t
+loc_is_nameless (loc_t *loc)
+{
+        gf_boolean_t ret = _gf_false;
+
+        GF_VALIDATE_OR_GOTO ("xlator", loc, out);
+
+        if ((!loc->parent && gf_uuid_is_null (loc->pargfid)) || !loc->name)
+                ret = _gf_true;
+out:
+        return ret;
+}
+
 int
 xlator_destroy (xlator_t *xl)
 {
diff --git a/libglusterfs/src/xlator.h b/libglusterfs/src/xlator.h
index c2959efbd95..5fb26547d56 100644
--- a/libglusterfs/src/xlator.h
+++ b/libglusterfs/src/xlator.h
@@ -1029,6 +1029,7 @@ void loc_pargfid (loc_t *loc, uuid_t pargfid);
 char* loc_gfid_utoa (loc_t *loc);
 gf_boolean_t loc_is_root (loc_t *loc);
 int32_t loc_build_child (loc_t *child, loc_t *parent, char *name);
+gf_boolean_t loc_is_nameless (loc_t *loc);
 int xlator_mem_acct_init (xlator_t *xl, int num_types);
 int is_gf_log_command (xlator_t *trans, const char *name, char *value);
 int glusterd_check_log_level (const char *value);
diff --git a/xlators/cluster/afr/src/afr-common.c b/xlators/cluster/afr/src/afr-common.c
index bd8acb6abb7..73550befc23 100644
--- a/xlators/cluster/afr/src/afr-common.c
+++ b/xlators/cluster/afr/src/afr-common.c
@@ -60,6 +60,9 @@ int
 afr_fav_child_reset_sink_xattrs_cbk (int ret, call_frame_t *frame,
                                      void *opaque);
 
+static void
+afr_discover_done (call_frame_t *frame, xlator_t *this);
+
 gf_boolean_t
 afr_is_consistent_io_possible (afr_local_t *local, afr_private_t *priv,
                                int32_t *op_errno)
@@ -1037,7 +1040,7 @@ int
 afr_refresh_selfheal_done (int ret, call_frame_t *heal, void *opaque)
 {
 	if (heal)
-		STACK_DESTROY (heal->root);
+                AFR_STACK_DESTROY (heal);
 	return 0;
 }
 
@@ -2421,13 +2424,25 @@ afr_lookup_sh_metadata_wrap (void *opaque)
                               "Unable to set link-count in dict ");
         }
 
-        inode = afr_selfheal_unlocked_lookup_on (frame, local->loc.parent,
-                                                 local->loc.name, local->replies,
-                                                 local->child_up, dict);
+        if (loc_is_nameless (&local->loc)) {
+                ret = afr_selfheal_unlocked_discover_on (frame, local->inode,
+                                                         local->loc.gfid,
+                                                         local->replies,
+                                                         local->child_up);
+        } else {
+                inode = afr_selfheal_unlocked_lookup_on (frame,
+                                                         local->loc.parent,
+                                                         local->loc.name,
+                                                         local->replies,
+                                                         local->child_up, dict);
+        }
         if (inode)
                 inode_unref (inode);
 out:
-        afr_lookup_done (frame, this);
+        if (loc_is_nameless (&local->loc))
+                afr_discover_done (frame, this);
+        else
+                afr_lookup_done (frame, this);
 
         if (dict)
                 dict_unref (dict);
@@ -2492,21 +2507,29 @@ afr_lookup_metadata_heal_check (call_frame_t *frame, xlator_t *this)
 
 {
         call_frame_t *heal = NULL;
+        afr_local_t *local = NULL;
         int ret            = 0;
 
+        local = frame->local;
         if (!afr_can_start_metadata_self_heal (frame, this))
                 goto out;
 
-        heal = copy_frame (frame);
-        if (heal)
-                heal->root->pid = GF_CLIENT_PID_SELF_HEALD;
+        heal = afr_frame_create (this);
+        if (!heal)
+                goto out;
+
         ret = synctask_new (this->ctx->env, afr_lookup_sh_metadata_wrap,
                             afr_refresh_selfheal_done, heal, frame);
-        if(ret)
+        if (ret)
                 goto out;
         return ret;
 out:
-        afr_lookup_done (frame, this);
+        if (loc_is_nameless (&local->loc))
+                afr_discover_done (frame, this);
+        else
+                afr_lookup_done (frame, this);
+        if (heal)
+                AFR_STACK_DESTROY (heal);
         return ret;
 }
 
@@ -2587,13 +2610,15 @@ afr_lookup_entry_heal (call_frame_t *frame, xlator_t *this)
 	}
 
 	if (need_heal) {
-		heal = copy_frame (frame);
-		if (heal)
-			heal->root->pid = GF_CLIENT_PID_SELF_HEALD;
+                heal = afr_frame_create (this);
+                if (!heal)
+                        goto metadata_heal;
 		ret = synctask_new (this->ctx->env, afr_lookup_selfheal_wrap,
 				    afr_refresh_selfheal_done, heal, frame);
-		if (ret)
+		if (ret) {
+                        AFR_STACK_DESTROY (heal);
 			goto metadata_heal;
+                }
                 return ret;
 	}
 metadata_heal:
@@ -2755,8 +2780,8 @@ afr_discover_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
 
         call_count = afr_frame_return (frame);
         if (call_count == 0) {
-               afr_set_need_heal (this, local);
-               afr_discover_done (frame, this);
+                afr_set_need_heal (this, local);
+                afr_lookup_metadata_heal_check (frame, this);
         }
 
 	return 0;
@@ -2969,7 +2994,7 @@ afr_lookup (call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *xattr_req)
         void          *gfid_req = NULL;
         int            ret = 0;
 
-	if (!loc->parent && gf_uuid_is_null (loc->pargfid)) {
+        if (loc_is_nameless (loc)) {
                 if (xattr_req)
                         dict_del (xattr_req, "gfid-req");
 		afr_discover (frame, this, loc, xattr_req);
diff --git a/xlators/cluster/afr/src/afr-self-heal.h b/xlators/cluster/afr/src/afr-self-heal.h
index 04463cccfc9..ded4903a4c7 100644
--- a/xlators/cluster/afr/src/afr-self-heal.h
+++ b/xlators/cluster/afr/src/afr-self-heal.h
@@ -145,6 +145,10 @@ int
 afr_selfheal_unlocked_discover (call_frame_t *frame, inode_t *inode,
 				uuid_t gfid, struct afr_reply *replies);
 
+int
+afr_selfheal_unlocked_discover_on (call_frame_t *frame, inode_t *inode,
+                                   uuid_t gfid, struct afr_reply *replies,
+                                   unsigned char *discover_on);
 inode_t *
 afr_selfheal_unlocked_lookup_on (call_frame_t *frame, inode_t *parent,
 				 const char *name, struct afr_reply *replies,