gfapi : Resolve "." and ".." only for named lookups

The patch https://review.gluster.org/#/c/17177 resolves "." and ".."
to corrosponding inodes and names before sending the request to the
backend server. But this will only work if inode and its parent is
linked properly. Incase of nameless lookup(applications like ganesha)
the inode of parent can be NULL(only gfid is send). So this patch will
resolve "." and ".." only if proper parent is available

Upstream reference
>Change-Id: I4c50258b0d896dabf000a547ab180b57df308a0b
>BUG: 1460514
>Signed-off-by: Jiffin Tony Thottan <jthottan@redhat.com>
>Reviewed-on: https://review.gluster.org/17502
>Smoke: Gluster Build System <jenkins@build.gluster.org>
>NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
>Reviewed-by: Poornima G <pgurusid@redhat.com>
>CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
>Reviewed-by: soumya k <skoduri@redhat.com>
>Reviewed-by: Jeff Darcy <jeff@pl.atyp.us>
>(cherry picked from commit a052b413242783f39cb3312a6a02bdd025b10f0c)

Change-Id: I4c50258b0d896dabf000a547ab180b57df308a0b
BUG: 1559352
Signed-off-by: Jiffin Tony Thottan <jthottan@redhat.com>

1 files changed, 64 insertions, 8 deletions

diff --git a/api/src/glfs-resolve.c b/api/src/glfs-resolve.c
index a2be87f1c1e..7ebd4f49ddf 100644
--- a/api/src/glfs-resolve.c
+++ b/api/src/glfs-resolve.c
@@ -236,6 +236,7 @@ glfs_resolve_component (struct glfs *fs, xlator_t *subvol, inode_t *parent,
 {
 	loc_t        loc = {0, };
 	inode_t     *inode = NULL;
+        inode_t     *temp_parent = NULL;
 	int          reval = 0;
 	int          ret = -1;
 	int          glret = -1;
@@ -244,14 +245,12 @@ glfs_resolve_component (struct glfs *fs, xlator_t *subvol, inode_t *parent,
 	dict_t      *xattr_req = NULL;
         uint64_t     ctx_value = LOOKUP_NOT_NEEDED;
 
-	loc.name = component;
-
 	loc.parent = inode_ref (parent);
 	gf_uuid_copy (loc.pargfid, parent->gfid);
 
-        /* At this point we should never have '.' or ".." in path */
         if (__is_root_gfid (parent->gfid) &&
-            (strcmp (component, "/") == 0)) {
+            ((strcmp (component, ".") == 0) ||
+             (strcmp (component, "..") == 0))) {
                 if (!force_lookup) {
                         inode = inode_ref (parent);
                 } else {
@@ -261,8 +260,68 @@ glfs_resolve_component (struct glfs *fs, xlator_t *subvol, inode_t *parent,
                 }
                 goto found;
         }
+        /* *
+        * if the component name is either "." or "..", it will try to
+        * resolve that if inode has a proper parent (named lookup).
+        *
+        * Below condition works like this
+        *
+        * Example 1 :
+        * Path /out_dir/dir/in_dir/.
+        *     In put values :
+        *         parent = in_dir
+        *         component : "."
+        *
+        *      Out put values:
+        *         parent : dir
+        *         component : "in_dir"
+        *
+        * Example 2 :
+        * Path /out_dir/dir/in_dir/..
+        *     In put values :
+        *         parent = in_dir
+        *         component : ".."
+        *
+        *     Out put values:
+        *         parent : output_dir
+        *         component : "dir"
+        *
+        * Incase of nameless lookup, both "." and ".." retained
+        */
+
+        if (strcmp (component, ".") == 0) {
+                loc.inode = inode_ref (parent);
+                temp_parent = inode_parent (loc.inode, 0, 0);
+                if (temp_parent) {
+                        inode_unref (loc.parent);
+                        loc.parent = temp_parent;
+                        inode_find_directory_name (loc.inode, &loc.name);
+                }
+
+        } else if (strcmp (component, "..") == 0) {
+                loc.inode = inode_parent (parent, 0, 0);
+                if (loc.inode) {
+                        temp_parent = inode_parent (loc.inode, 0, 0);
+                        if (temp_parent) {
+                                inode_unref (loc.parent);
+                                loc.parent = temp_parent;
+                                inode_find_directory_name (loc.inode, &loc.name);
+                        } else if (__is_root_gfid (loc.inode->gfid)) {
+                                inode_unref (loc.parent);
+                                loc.parent = inode_ref (loc.inode);
+                                loc.name = "";
+                        } else {
+                                inode_unref (loc.inode);
+                                loc.inode = NULL;
+                        }
+
+                }
+        } else
+                loc.inode = inode_grep (parent->table, parent, component);
+
+        if (!loc.name)
+                loc.name = component;
 
-        loc.inode = inode_grep (parent->table, parent, component);
 	if (loc.inode) {
 		gf_uuid_copy (loc.gfid, loc.inode->gfid);
 		reval = 1;
@@ -357,7 +416,6 @@ found:
 out:
 	if (xattr_req)
 		dict_unref (xattr_req);
-
 	loc_wipe (&loc);
 
 	return inode;
@@ -377,7 +435,6 @@ priv_glfs_resolve_at (struct glfs *fs, xlator_t *subvol, inode_t *at,
 	char       *next_component = NULL;
 	int         ret = -1;
 	struct iatt ciatt = {0, };
-        char        dentry_name[PATH_MAX]  = {0, };
 
 	DECLARE_OLD_THIS;
 	__GLFS_ENTRY_VALIDATE_FS(fs, invalid_fs);
@@ -409,7 +466,6 @@ priv_glfs_resolve_at (struct glfs *fs, xlator_t *subvol, inode_t *at,
 		if (parent)
 			inode_unref (parent);
 		parent = inode;
-                glusterfs_normalize_dentry (&parent, &component, dentry_name);
 		inode = glfs_resolve_component (fs, subvol, parent,
 						component, &ciatt,
 						/* force hard lookup on the last