xlators/features/namespace: Add namespace xlator and link into brick graph

The following release-3.8-fb branch patch is upstreamed:
> features/namespace: Add namespace xlator and link into brick graph
> Commit ID: dbd30776f26e
> https://review.gluster.org/#/c/18041/
> By Michael Goulet <mgoulet@fb.com>

Changes in this patch:
Removes extra config.h and namespace.h file in namespace.c
Adds default_getspec_cbk to libglusterfs.sym
Rename dict_for_each to dict_foreach_inline
Remove fd.h header file stack.h
Add test case for truncate, open and symlink

This patch is required to forward port io-threads namespace patch.
Updates: #401

Change-Id: Ib88c95b89eecee9b8957df8a4c8712c899c761d1
Signed-off-by: Varsha Rao <varao@redhat.com>

4 files changed, 1410 insertions, 0 deletions

diff --git a/xlators/features/namespace/Makefile.am b/xlators/features/namespace/Makefile.am
new file mode 100644
index 00000000000..a985f42a877
--- /dev/null
+++ b/xlators/features/namespace/Makefile.am
@@ -0,0 +1,3 @@
+SUBDIRS = src
+
+CLEANFILES =
diff --git a/xlators/features/namespace/src/Makefile.am b/xlators/features/namespace/src/Makefile.am
new file mode 100644
index 00000000000..e355d42cf4e
--- /dev/null
+++ b/xlators/features/namespace/src/Makefile.am
@@ -0,0 +1,17 @@
+xlator_LTLIBRARIES = namespace.la
+xlatordir = $(libdir)/glusterfs/$(PACKAGE_VERSION)/xlator/features
+
+namespace_la_LDFLAGS = -module $(GF_XLATOR_DEFAULT_LDFLAGS)
+
+namespace_la_SOURCES = namespace.c
+namespace_la_LIBADD = $(top_builddir)/libglusterfs/src/libglusterfs.la
+
+noinst_HEADERS = namespace.h
+
+AM_CPPFLAGS = $(GF_CPPFLAGS) -I$(top_srcdir)/libglusterfs/src \
+	-I$(top_srcdir)/rpc/xdr/src -I$(top_builddir)/rpc/xdr/src \
+	-I$(top_srcdir)/xlators/lib/src
+
+AM_CFLAGS = -Wall $(GF_CFLAGS)
+
+CLEANFILES =
diff --git a/xlators/features/namespace/src/namespace.c b/xlators/features/namespace/src/namespace.c
new file mode 100644
index 00000000000..cabd247da0c
--- /dev/null
+++ b/xlators/features/namespace/src/namespace.c
@@ -0,0 +1,1367 @@
+/*
+ * Copyright (c) 2008-2012 Red Hat, Inc. <http://www.redhat.com>
+ * This file is part of GlusterFS.
+ *
+ * This file is licensed to you under your choice of the GNU Lesser
+ * General Public License, version 3 or any later version (LGPLv3 or
+ * later), or the GNU General Public License, version 2 (GPLv2), in all
+ * cases as published by the Free Software Foundation.
+ *
+ * xlators/features/namespace:
+ *      This translator tags each request with a namespace hash,
+ *      which then can be used in later translators to track and
+ *      throttle fops per namespace.
+ */
+
+#include <sys/types.h>
+
+#include "defaults.h"
+#include "glusterfs.h"
+#include "hashfn.h"
+#include "logging.h"
+#include "namespace.h"
+
+/* Return codes for common path parsing functions. */
+enum _path_parse_result {
+        PATH_PARSE_RESULT_NO_PATH = 0,
+        PATH_PARSE_RESULT_FOUND   = 1,
+        PATH_PARSE_RESULT_IS_GFID = 2,
+};
+
+typedef enum _path_parse_result path_parse_result_t;
+
+/* Clean up an ns_local struct. Wipe a loc (its inode is ref'd, so we're good.)
+ */
+static inline void
+ns_local_cleanup (ns_local_t *local)
+{
+        if (!local) {
+                return;
+        }
+
+        loc_wipe (&local->loc);
+        GF_FREE (local);
+}
+
+/* Create a new ns_local. We ref the inode, fake a new loc struct, and stash
+ * the stub given to us. */
+static inline ns_local_t *
+ns_local_new (call_stub_t *stub, inode_t *inode)
+{
+        ns_local_t *local = NULL;
+        loc_t       loc   = {0, };
+
+        if (!stub || !inode) {
+                goto out;
+        }
+
+        local = GF_CALLOC (1, sizeof (ns_local_t), 0);
+        if (local == NULL) {
+                goto out;
+        }
+
+        /* Set up a fake loc_t struct to give to the getxattr call. */
+        gf_uuid_copy (loc.gfid, inode->gfid);
+        loc.inode = inode_ref (inode);
+
+        /* If for some reason inode_ref() fails, then just give up. */
+        if (!loc.inode) {
+                GF_FREE (local);
+                goto out;
+        }
+
+        local->stub = stub;
+        local->loc = loc;
+
+out:
+        return local;
+}
+
+/* Try parsing a path string. If the path string is a GFID, then return
+ * with PATH_PARSE_RESULT_IS_GFID. If we have no namespace (i.e. '/') then
+ * return PATH_PARSE_RESULT_NO_PATH and set the hash to 1. Otherwise, hash the
+ * namespace and store it in the info struct. */
+static path_parse_result_t
+parse_path (ns_info_t *info, const char *path)
+{
+        int         len      = 0;
+        const char *ns_begin = path;
+        const char *ns_end   = NULL;
+
+        if (!path || strlen (path) == 0) {
+                return PATH_PARSE_RESULT_NO_PATH;
+        }
+
+        if (path[0] == '<') {
+                return PATH_PARSE_RESULT_IS_GFID;
+        }
+
+        /* Right now we only want the top-level directory, so
+         * skip the initial '/' and read until the next '/'. */
+        while (*ns_begin == '/') {
+                ns_begin++;
+        }
+
+        /* ns_end will point to the next '/' or NULL if there is no delimiting
+         * '/' (i.e. "/directory" or the top level "/") */
+        ns_end = strchr (ns_begin, '/');
+        len = ns_end ? (ns_end - ns_begin) : strlen (ns_begin);
+
+        if (len != 0) {
+                info->hash = SuperFastHash (ns_begin, len);
+        } else {
+                /* If our substring is empty, then we can hash '/' instead.
+                 * '/' is used in the namespace config for the top-level
+                 * namespace. */
+                info->hash = SuperFastHash ("/", 1);
+        }
+
+        info->found = _gf_true;
+        return PATH_PARSE_RESULT_FOUND;
+}
+
+/* Cache namespace info stored in the stack (info) into the inode. */
+static int
+ns_inode_ctx_put (inode_t *inode, xlator_t *this, ns_info_t *info)
+{
+        ns_info_t *cached_ns_info = NULL;
+        uint64_t   ns_as_64       = 0;
+        int        ret            = -1;
+
+        if (!inode || !this) {
+                gf_log (this->name, GF_LOG_WARNING,
+                        "Need a valid inode and xlator to cache ns_info.");
+                ret = -1;
+                goto out;
+        }
+
+        cached_ns_info = GF_CALLOC (1, sizeof (ns_info_t), 0);
+
+        /* If we've run out of memory, then return ENOMEM. */
+        if (cached_ns_info == NULL) {
+                gf_log (this->name, GF_LOG_WARNING,
+                        "No memory to cache ns_info.");
+                ret = -(ENOMEM);
+                goto out;
+        }
+
+        *cached_ns_info = *info;
+        ns_as_64 = (uint64_t)cached_ns_info;
+
+        ret = inode_ctx_put (inode, this, ns_as_64);
+
+        if (ret) {
+                goto out;
+        }
+
+        ret = 0;
+out:
+        if (ret && cached_ns_info) {
+                GF_FREE (cached_ns_info);
+        }
+
+        return ret;
+}
+
+/* Retrieve namespace info cached in the inode into the stack for use in later
+ * translators. */
+static int
+ns_inode_ctx_get (inode_t *inode, xlator_t *this, ns_info_t *info)
+{
+        ns_info_t *cached_ns_info = NULL;
+        uint64_t   ns_as_64       = 0;
+        int        ret            = -1;
+
+        if (!inode) {
+                ret = -ENOENT;
+                goto out;
+        }
+
+        ret = inode_ctx_get (inode, this, &ns_as_64);
+
+        if (!ret) {
+                cached_ns_info = (ns_info_t *)ns_as_64;
+                *info = *cached_ns_info;
+        }
+
+out:
+        return ret;
+}
+
+/* This callback is the top of the unwind path of our attempt to get the path
+ * manually from the posix translator. We'll try to parse the path returned
+ * if it exists, then cache the hash if possible. Then just return to the
+ * default stub that we provide in the local, since there's nothing else to do
+ * once we've gotten the namespace hash. */
+int32_t
+get_path_resume_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
+                     int32_t op_ret, int32_t op_errno, dict_t *dict,
+                     dict_t *xdata)
+{
+        path_parse_result_t  ret          = PATH_PARSE_RESULT_NO_PATH;
+        call_frame_t        *resume_frame = NULL;
+        ns_local_t          *local        = NULL;
+        call_stub_t         *stub         = NULL;
+        ns_info_t           *info         = NULL;
+        char                *path         = NULL;
+
+        GF_VALIDATE_OR_GOTO (this->name, frame, out);
+        local = frame->local;
+
+        GF_VALIDATE_OR_GOTO (this->name, local, out);
+        stub = local->stub;
+
+        GF_VALIDATE_OR_GOTO (this->name, stub, out);
+        /* Get the ns_info from the frame that we will eventually resume,
+         * not the frame that we're going to destroy (frame). */
+        resume_frame = stub->frame;
+
+        GF_VALIDATE_OR_GOTO (this->name, resume_frame, out);
+        GF_VALIDATE_OR_GOTO (this->name, resume_frame->root, out);
+        info = &resume_frame->root->ns_info;
+
+        GF_VALIDATE_OR_GOTO (this->name, dict, out);
+
+        /* If we get a value back for the GET_ANCESTRY_PATH_KEY, then we
+         * try to access it and parse it like a path. */
+        if (!op_ret && !dict_get_str (dict, GET_ANCESTRY_PATH_KEY, &path)) {
+                gf_log (this->name, GF_LOG_DEBUG, "G>P %s retrieved path %s",
+                        uuid_utoa (local->loc.gfid), path);
+                /* Now let's parse a path, finally. */
+                ret = parse_path (info, path);
+        }
+
+        if (ret == PATH_PARSE_RESULT_FOUND) {
+                /* If we finally found namespace, then stash it. */
+                ns_inode_ctx_put (local->loc.inode, this, info);
+
+                gf_log (this->name, GF_LOG_DEBUG,
+                        "G>P %s %10u namespace found %s",
+                        uuid_utoa (local->loc.inode->gfid), info->hash, path);
+        } else if (ret == PATH_PARSE_RESULT_NO_PATH) {
+                gf_log (this->name, GF_LOG_WARNING, "G>P %s has no path",
+                        uuid_utoa (local->loc.inode->gfid));
+        } else if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                gf_log (this->name, GF_LOG_WARNING,
+                        "G>P %s winding failed, still have gfid",
+                        uuid_utoa (local->loc.inode->gfid));
+        }
+
+out:
+        /* Make sure to clean up local finally. */
+
+        if (frame) {
+                frame->local = NULL;
+                STACK_DESTROY (frame->root);
+        }
+
+        if (local) {
+                ns_local_cleanup (local);
+        }
+
+        if (stub) {
+                call_resume (stub);
+        }
+
+        return 0;
+}
+
+/* This function tries first to set a namespace based on the information that
+ * it can retrieve from an `loc_t`. This includes first looking for a cached
+ * namespace in the inode, then trying to parse the path string in the `loc_t`
+ * struct. If this fails, then it will try to call inode_path. */
+static path_parse_result_t
+set_ns_from_loc (const char *fn, call_frame_t *frame, xlator_t *this,
+                 loc_t *loc)
+{
+        path_parse_result_t ret = PATH_PARSE_RESULT_NO_PATH;
+        ns_private_t *priv      = (ns_private_t *)this->private;
+        ns_info_t *info         = &frame->root->ns_info;
+        char *path              = NULL;
+
+        info->hash = 0;
+        info->found = _gf_false;
+
+        if (!priv->tag_namespaces) {
+                return ret;
+        }
+
+        /* This is our first pass at trying to get a path. Try getting
+         * from the inode context, then from the loc's path itself. */
+        if (!loc || !loc->path || !loc->inode) {
+                ret = PATH_PARSE_RESULT_NO_PATH;
+        } else if (!ns_inode_ctx_get (loc->inode, this, info)) {
+                ret = PATH_PARSE_RESULT_FOUND;
+        } else {
+                ret = parse_path (info, loc->path);
+                gf_log (this->name, GF_LOG_DEBUG, "%s: LOC retrieved path %s",
+                        fn, loc->path);
+
+                if (ret == PATH_PARSE_RESULT_FOUND) {
+                        ns_inode_ctx_put (loc->inode, this, info);
+                }
+        }
+
+        /* Keep trying by calling inode_path next, making sure to copy
+        the loc's gfid into its inode if necessary. */
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                if (gf_uuid_is_null (loc->inode->gfid)) {
+                        gf_uuid_copy (loc->inode->gfid, loc->gfid);
+                }
+
+                if (inode_path (loc->inode, NULL, &path) >= 0 && path) {
+                        ret = parse_path (info, loc->path);
+                        gf_log (this->name, GF_LOG_DEBUG,
+                                "%s: LOC retrieved path %s", fn, path);
+
+                        if (ret == PATH_PARSE_RESULT_FOUND) {
+                                ns_inode_ctx_put (loc->inode, this, info);
+                        }
+                }
+
+                if (path) {
+                        GF_FREE (path);
+                }
+        }
+
+        /* Report our status, and if we have a GFID, we'll eventually try a
+         * GET_ANCESTRY_PATH_KEY wind when we return from this function. */
+        if (ret == PATH_PARSE_RESULT_FOUND) {
+                gf_log (this->name, GF_LOG_DEBUG,
+                        "%s: LOC %s %10u namespace found for %s", fn,
+                        uuid_utoa (loc->inode->gfid), info->hash, loc->path);
+        } else if (ret == PATH_PARSE_RESULT_NO_PATH) {
+                gf_log (this->name, GF_LOG_WARNING, "%s: LOC has no path", fn);
+        } else if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                /* Make sure to copy the inode's gfid for the eventual wind. */
+                if (gf_uuid_is_null (loc->inode->gfid)) {
+                        gf_uuid_copy (loc->inode->gfid, loc->gfid);
+                }
+
+                gf_log (this->name, GF_LOG_DEBUG,
+                        "%s: LOC %s winding, looking for path", fn,
+                        uuid_utoa (loc->inode->gfid));
+        }
+
+        return ret;
+}
+
+/* This function tries first to set a namespace based on the information that
+ * it can retrieve from an `fd_t`. This includes first looking for a cached
+ * namespace in the inode, then trying to call inode_path manually. */
+static path_parse_result_t
+set_ns_from_fd (const char *fn, call_frame_t *frame, xlator_t *this, fd_t *fd)
+{
+        path_parse_result_t  ret  = PATH_PARSE_RESULT_NO_PATH;
+        ns_private_t        *priv = (ns_private_t *)this->private;
+        ns_info_t           *info = &frame->root->ns_info;
+        char                *path = NULL;
+
+        info->hash = 0;
+        info->found = _gf_false;
+
+        if (!priv->tag_namespaces) {
+                return ret;
+        }
+
+        /* This is our first pass at trying to get a path. Try getting
+         * from the inode context, then inode_path. */
+        if (!fd || !fd->inode) {
+                ret = PATH_PARSE_RESULT_NO_PATH;
+        } else if (!ns_inode_ctx_get (fd->inode, this, info)) {
+                ret = PATH_PARSE_RESULT_FOUND;
+        } else if (inode_path (fd->inode, NULL, &path) >= 0 && path) {
+                ret = parse_path (info, path);
+                gf_log (this->name, GF_LOG_DEBUG, "%s: FD  retrieved path %s",
+                        fn, path);
+
+                if (ret == PATH_PARSE_RESULT_FOUND) {
+                        ns_inode_ctx_put (fd->inode, this, info);
+                }
+        }
+
+        if (path) {
+                GF_FREE (path);
+        }
+
+        /* Report our status, and if we have a GFID, we'll eventually try a
+         * GET_ANCESTRY_PATH_KEY wind when we return from this function. */
+        if (ret == PATH_PARSE_RESULT_FOUND) {
+                gf_log (this->name, GF_LOG_DEBUG, "%s: FD  %s %10u namespace found",
+                        fn, uuid_utoa (fd->inode->gfid), info->hash);
+        } else if (ret == PATH_PARSE_RESULT_NO_PATH) {
+                gf_log (this->name, GF_LOG_WARNING, "%s: FD  has no path", fn);
+        } else if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                gf_log (this->name, GF_LOG_DEBUG,
+                        "%s: FD  %s winding, looking for path",
+                        fn, uuid_utoa (fd->inode->gfid));
+        }
+
+        return ret;
+}
+
+/* This macro does the work of winding down a call of `getxattr` in the case
+ * that we have to retrieve the path manually. It assumes that there is a label
+ * called `wind` and the existence of several basic variables (frame, this),
+ * but otherwise is general enough for any fop (fd- or loc-based.) */
+#define GET_ANCESTRY_PATH_WIND(fop, inode, args...)                            \
+        do {                                                                   \
+                ns_info_t *info         = &frame->root->ns_info;               \
+                call_frame_t *new_frame = NULL;                                \
+                ns_local_t *local       = NULL;                                \
+                call_stub_t *stub       = NULL;                                \
+                                                                               \
+                gf_log (this->name, GF_LOG_DEBUG,                              \
+                        "    %s winding, looking for path",                    \
+                        uuid_utoa (inode->gfid));                              \
+                                                                               \
+                new_frame = create_frame (this, this->ctx->pool);              \
+                if (!new_frame) {                                              \
+                        gf_log (this->name, GF_LOG_ERROR,                      \
+                                "Cannot allocate new call frame.");            \
+                        goto wind;                                             \
+                }                                                              \
+                                                                               \
+                stub = fop_##fop##_stub (frame, default_##fop, args);          \
+                if (!stub) {                                                   \
+                        gf_log (this->name, GF_LOG_ERROR,                      \
+                                "Cannot allocate function stub.");             \
+                        goto wind;                                             \
+                }                                                              \
+                                                                               \
+                new_frame->root->uid = 0;                                      \
+                new_frame->root->gid = 0;                                      \
+                /* Put a phony "not found" NS info into this call. */          \
+                new_frame->root->ns_info = *info;                              \
+                                                                               \
+                local = ns_local_new (stub, inode);                            \
+                if (!local) {                                                  \
+                        gf_log (this->name, GF_LOG_ERROR,                      \
+                                "Cannot allocate function local.");            \
+                        goto wind;                                             \
+                }                                                              \
+                                                                               \
+                new_frame->local = local;                                      \
+                /* After allocating a new frame, a call stub (to               \
+                 * resume our current fop), and a local variables              \
+                 * struct (for our loc to getxattr and our resume              \
+                 * stub), call getxattr and unwind to get_path_resume_cbk.     \
+                 */                                                            \
+                STACK_WIND (new_frame, get_path_resume_cbk,                    \
+                            FIRST_CHILD (this),                                \
+                            FIRST_CHILD (this)->fops->getxattr, &local->loc,   \
+                            GET_ANCESTRY_PATH_KEY, NULL);                      \
+        } while (0)
+
+int32_t
+ns_rmdir (call_frame_t *frame, xlator_t *this, loc_t *loc, int xflags,
+          dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (rmdir, loc->inode, loc, xflags, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_rmdir_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->rmdir, loc, xflags, xdata);
+        return 0;
+}
+
+int32_t
+ns_unlink (call_frame_t *frame, xlator_t *this, loc_t *loc, int xflags,
+           dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (unlink, loc->inode, loc, xflags, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_unlink_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->unlink, loc, xflags, xdata);
+        return 0;
+}
+
+int32_t
+ns_rename (call_frame_t *frame, xlator_t *this, loc_t *oldloc, loc_t *newloc,
+           dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, newloc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (rename, newloc->inode, oldloc, newloc,
+                                        xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_rename_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->rename, oldloc, newloc, xdata);
+        return 0;
+}
+
+int32_t
+ns_link (call_frame_t *frame, xlator_t *this, loc_t *oldloc, loc_t *newloc,
+         dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, newloc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (link, newloc->inode, oldloc, newloc,
+                                        xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_link_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->link, oldloc, newloc, xdata);
+        return 0;
+}
+
+int32_t
+ns_mkdir (call_frame_t *frame, xlator_t *this, loc_t *loc, mode_t mode,
+          mode_t umask, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (mkdir, loc->inode, loc, mode, umask,
+                                        xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_mkdir_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->mkdir, loc, mode, umask, xdata);
+        return 0;
+}
+
+int32_t
+ns_symlink (call_frame_t *frame, xlator_t *this, const char *linkname,
+            loc_t *loc, mode_t umask, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (symlink, loc->inode, linkname, loc,
+                                        umask, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_symlink_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->symlink, linkname, loc, umask,
+                    xdata);
+        return 0;
+}
+
+int32_t
+ns_mknod (call_frame_t *frame, xlator_t *this, loc_t *loc, mode_t mode,
+          dev_t dev, mode_t umask, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (mknod, loc->inode, loc, mode, dev,
+                                        umask, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_mknod_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->mknod, loc, mode, dev, umask,
+                    xdata);
+        return 0;
+}
+
+int32_t
+ns_create (call_frame_t *frame, xlator_t *this, loc_t *loc, int32_t flags,
+           mode_t mode, mode_t umask, fd_t *fd, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (create, loc->inode, loc, flags, mode,
+                                        umask, fd, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_create_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->create, loc, flags, mode, umask,
+                    fd, xdata);
+        return 0;
+}
+
+int32_t
+ns_fsetattr (call_frame_t *frame, xlator_t *this, fd_t *fd, struct iatt *stbuf,
+             int32_t valid, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (fsetattr, fd->inode, fd, stbuf, valid,
+                                        xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_fsetattr_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->fsetattr, fd, stbuf, valid,
+                    xdata);
+        return 0;
+}
+
+int32_t
+ns_setattr (call_frame_t *frame, xlator_t *this, loc_t *loc, struct iatt *stbuf,
+            int32_t valid, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (setattr, loc->inode, loc, stbuf, valid,
+                                        xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_setattr_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->setattr, loc, stbuf, valid,
+                    xdata);
+        return 0;
+}
+
+int32_t
+ns_fremovexattr (call_frame_t *frame, xlator_t *this, fd_t *fd,
+                 const char *name, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (fremovexattr, fd->inode, fd, name,
+                                        xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_fremovexattr_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->fremovexattr, fd, name, xdata);
+        return 0;
+}
+
+int32_t
+ns_removexattr (call_frame_t *frame, xlator_t *this, loc_t *loc,
+                const char *name, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (removexattr, loc->inode, loc, name,
+                                        xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_removexattr_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->removexattr, loc, name, xdata);
+        return 0;
+}
+
+int32_t
+ns_setxattr (call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *dict,
+             int32_t flags, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (setxattr, loc->inode, loc, dict, flags,
+                                        xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_setxattr_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->setxattr, loc, dict, flags,
+                    xdata);
+        return 0;
+}
+
+int32_t
+ns_fsetxattr (call_frame_t *frame, xlator_t *this, fd_t *fd, dict_t *dict,
+              int32_t flags, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (fsetxattr, fd->inode, fd, dict, flags,
+                                        xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_fsetxattr_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->fsetxattr, fd, dict, flags,
+                    xdata);
+        return 0;
+}
+
+int32_t
+ns_truncate (call_frame_t *frame, xlator_t *this, loc_t *loc, off_t offset,
+             dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (truncate, loc->inode, loc, offset,
+                                        xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_truncate_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->truncate, loc, offset, xdata);
+        return 0;
+}
+
+int32_t
+ns_ftruncate (call_frame_t *frame, xlator_t *this, fd_t *fd, off_t offset,
+              dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (ftruncate, fd->inode, fd, offset,
+                                        xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_ftruncate_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->ftruncate, fd, offset, xdata);
+        return 0;
+}
+
+int32_t
+ns_writev (call_frame_t *frame, xlator_t *this, fd_t *fd, struct iovec *vector,
+           int32_t count, off_t offset, uint32_t flags, struct iobref *iobref,
+           dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (writev, fd->inode, fd, vector, count,
+                                        offset, flags, iobref, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_writev_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->writev, fd, vector, count, offset,
+                    flags, iobref, xdata);
+        return 0;
+}
+
+int32_t
+ns_lookup (call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (lookup, loc->inode, loc, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_lookup_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->lookup, loc, xdata);
+        return 0;
+}
+
+int32_t
+ns_stat (call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (stat, loc->inode, loc, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_stat_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->stat, loc, xdata);
+        return 0;
+}
+
+int32_t
+ns_fstat (call_frame_t *frame, xlator_t *this, fd_t *fd, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (fstat, fd->inode, fd, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_fstat_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->fstat, fd, xdata);
+        return 0;
+}
+
+int32_t
+ns_readlink (call_frame_t *frame, xlator_t *this, loc_t *loc, size_t size,
+             dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (readlink, loc->inode, loc, size, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_readlink_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->readlink, loc, size, xdata);
+        return 0;
+}
+
+int32_t
+ns_access (call_frame_t *frame, xlator_t *this, loc_t *loc, int32_t mask,
+           dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (access, loc->inode, loc, mask, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_access_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->access, loc, mask, xdata);
+        return 0;
+}
+
+int32_t
+ns_open (call_frame_t *frame, xlator_t *this, loc_t *loc, int32_t flags,
+         fd_t *fd, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (open, fd->inode, loc, flags, fd, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_open_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->open, loc, flags, fd, xdata);
+        return 0;
+}
+
+int32_t
+ns_readv (call_frame_t *frame, xlator_t *this, fd_t *fd, size_t size,
+          off_t offset, uint32_t flags, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (readv, fd->inode, fd, size, offset,
+                                        flags, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_readv_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->readv, fd, size, offset, flags,
+                    xdata);
+        return 0;
+}
+
+int32_t
+ns_flush (call_frame_t *frame, xlator_t *this, fd_t *fd, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (flush, fd->inode, fd, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_flush_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->flush, fd, xdata);
+        return 0;
+}
+
+int32_t
+ns_fsync (call_frame_t *frame, xlator_t *this, fd_t *fd, int32_t datasync,
+          dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (fsync, fd->inode, fd, datasync, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_fsync_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->fsync, fd, datasync, xdata);
+        return 0;
+}
+
+int32_t
+ns_opendir (call_frame_t *frame, xlator_t *this, loc_t *loc, fd_t *fd,
+            dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (opendir, loc->inode, loc, fd, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_opendir_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->opendir, loc, fd, xdata);
+        return 0;
+}
+
+int32_t
+ns_fsyncdir (call_frame_t *frame, xlator_t *this, fd_t *fd, int32_t datasync,
+             dict_t *xdata)
+
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (fsyncdir, fd->inode, fd, datasync,
+                                        xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_fsyncdir_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->fsyncdir, fd, datasync, xdata);
+        return 0;
+}
+
+int32_t
+ns_rchecksum (call_frame_t *frame, xlator_t *this, fd_t *fd, off_t offset,
+              int32_t len, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (rchecksum, fd->inode, fd, offset, len,
+                                        xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_rchecksum_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->rchecksum, fd, offset, len,
+                    xdata);
+        return 0;
+}
+
+int32_t
+ns_statfs (call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (statfs, loc->inode, loc, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_statfs_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->statfs, loc, xdata);
+        return 0;
+}
+
+int32_t
+ns_inodelk (call_frame_t *frame, xlator_t *this, const char *volume, loc_t *loc,
+            int32_t cmd, struct gf_flock *flock, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (inodelk, loc->inode, volume, loc, cmd,
+                                        flock, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_inodelk_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->inodelk, volume, loc, cmd, flock,
+                    xdata);
+        return 0;
+}
+
+int32_t
+ns_finodelk (call_frame_t *frame, xlator_t *this, const char *volume, fd_t *fd,
+             int32_t cmd, struct gf_flock *flock, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (finodelk, fd->inode, volume, fd, cmd,
+                                        flock, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_finodelk_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->finodelk, volume, fd, cmd, flock,
+                    xdata);
+        return 0;
+}
+
+int32_t
+ns_entrylk (call_frame_t *frame, xlator_t *this, const char *volume, loc_t *loc,
+            const char *basename, entrylk_cmd cmd, entrylk_type type,
+            dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (entrylk, loc->inode, volume, loc,
+                                        basename, cmd, type, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_entrylk_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->entrylk, volume, loc, basename,
+                    cmd, type, xdata);
+        return 0;
+}
+
+int32_t
+ns_fentrylk (call_frame_t *frame, xlator_t *this, const char *volume, fd_t *fd,
+             const char *basename, entrylk_cmd cmd, entrylk_type type,
+             dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (fentrylk, fd->inode, volume, fd,
+                                        basename, cmd, type, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_fentrylk_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->fentrylk, volume, fd, basename,
+                    cmd, type, xdata);
+        return 0;
+}
+
+int32_t
+ns_fgetxattr (call_frame_t *frame, xlator_t *this, fd_t *fd, const char *name,
+              dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (fgetxattr, fd->inode, fd, name, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_fgetxattr_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->fgetxattr, fd, name, xdata);
+        return 0;
+}
+
+int32_t
+ns_getxattr (call_frame_t *frame, xlator_t *this, loc_t *loc, const char *name,
+             dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (getxattr, loc->inode, loc, name, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_getxattr_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->getxattr, loc, name, xdata);
+        return 0;
+}
+
+int32_t
+ns_lk (call_frame_t *frame, xlator_t *this, fd_t *fd, int32_t cmd,
+       struct gf_flock *flock, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (lk, fd->inode, fd, cmd, flock, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_lk_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->lk, fd, cmd, flock, xdata);
+        return 0;
+}
+
+int32_t
+ns_readdir (call_frame_t *frame, xlator_t *this, fd_t *fd, size_t size,
+            off_t offset, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (readdir, fd->inode, fd, size, offset,
+                                        xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_readdir_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->readdir, fd, size, offset, xdata);
+
+        return 0;
+}
+
+int32_t
+ns_readdirp (call_frame_t *frame, xlator_t *this, fd_t *fd, size_t size,
+             off_t offset, dict_t *dict)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (readdirp, fd->inode, fd, size, offset,
+                                        dict);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_readdirp_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->readdirp, fd, size, offset, dict);
+        return 0;
+}
+
+int32_t
+ns_xattrop (call_frame_t *frame, xlator_t *this, loc_t *loc,
+            gf_xattrop_flags_t flags, dict_t *dict, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_loc (__FUNCTION__, frame, this, loc);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (xattrop, loc->inode, loc, flags, dict,
+                                        xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_xattrop_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->xattrop, loc, flags, dict, xdata);
+
+        return 0;
+}
+
+int32_t
+ns_fxattrop (call_frame_t *frame, xlator_t *this, fd_t *fd,
+             gf_xattrop_flags_t flags, dict_t *dict, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (fxattrop, fd->inode, fd, flags, dict,
+                                        xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_fxattrop_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->fxattrop, fd, flags, dict, xdata);
+
+        return 0;
+}
+
+
+int32_t
+ns_getspec (call_frame_t *frame, xlator_t *this, const char *key, int32_t flag)
+{
+        STACK_WIND (frame, default_getspec_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->getspec, key, flag);
+        return 0;
+}
+
+int32_t
+ns_fallocate (call_frame_t *frame, xlator_t *this, fd_t *fd, int32_t keep_size,
+              off_t offset, size_t len, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (fallocate, fd->inode, fd, keep_size,
+                                        offset, len, xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_fallocate_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->fallocate, fd, keep_size, offset,
+                    len, xdata);
+        return 0;
+}
+
+int32_t
+ns_discard (call_frame_t *frame, xlator_t *this, fd_t *fd, off_t offset,
+            size_t len, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (discard, fd->inode, fd, offset, len,
+                                        xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_discard_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->discard, fd, offset, len, xdata);
+        return 0;
+}
+
+int32_t
+ns_zerofill (call_frame_t *frame, xlator_t *this, fd_t *fd, off_t offset,
+             off_t len, dict_t *xdata)
+{
+        path_parse_result_t ret = set_ns_from_fd (__FUNCTION__, frame, this, fd);
+
+        if (ret == PATH_PARSE_RESULT_IS_GFID) {
+                GET_ANCESTRY_PATH_WIND (zerofill, fd->inode, fd, offset, len,
+                                        xdata);
+                return 0;
+        }
+wind:
+        STACK_WIND (frame, default_zerofill_cbk, FIRST_CHILD (this),
+                    FIRST_CHILD (this)->fops->zerofill, fd, offset, len, xdata);
+        return 0;
+}
+
+int
+ns_forget (xlator_t *this, inode_t *inode)
+{
+        uint64_t ns_as_64 = 0;
+        ns_info_t *info   = NULL;
+
+        inode_ctx_del (inode, this, &ns_as_64);
+
+        if (!ns_as_64) {
+                return 0;
+        }
+
+        info = (ns_info_t *)ns_as_64;
+        GF_FREE (info);
+
+        return 0;
+}
+
+int32_t
+init (xlator_t *this)
+{
+        int32_t ret        = -1;
+        ns_private_t *priv = NULL;
+
+        GF_VALIDATE_OR_GOTO (GF_NAMESPACE, this, out);
+
+        if (!this->children || this->children->next) {
+                gf_log (this->name, GF_LOG_ERROR,
+                        "translator needs a single subvolume.");
+                goto out;
+        }
+
+        if (!this->parents) {
+                gf_log (this->name, GF_LOG_ERROR,
+                        "dangling volume. please check volfile.");
+                goto out;
+        }
+
+        priv = GF_CALLOC (1, sizeof (ns_private_t), 0);
+
+        if (!priv) {
+                gf_log (this->name, GF_LOG_ERROR,
+                        "Can't allocate ns_priv structure.");
+                goto out;
+        }
+
+        GF_OPTION_INIT ("tag-namespaces", priv->tag_namespaces, bool, out);
+
+        gf_log (this->name, GF_LOG_INFO, "Namespace xlator loaded");
+        this->private = priv;
+        ret           = 0;
+
+out:
+        if (ret) {
+                GF_FREE (priv);
+        }
+
+        return ret;
+}
+
+void
+fini (xlator_t *this)
+{
+        GF_FREE (this->private);
+}
+
+int
+reconfigure (xlator_t *this, dict_t *options)
+{
+        int ret            = -1;
+        ns_private_t *priv = NULL;
+
+        GF_VALIDATE_OR_GOTO (this->name, this, out);
+        GF_VALIDATE_OR_GOTO (this->name, this->private, out);
+        GF_VALIDATE_OR_GOTO (this->name, options, out);
+
+        priv = (ns_private_t *)this->private;
+
+        GF_OPTION_RECONF ("tag-namespaces", priv->tag_namespaces, options, bool,
+                          out);
+
+        ret = 0;
+out:
+        return ret;
+}
+
+struct xlator_fops fops = {
+        .lookup       = ns_lookup,
+        .stat         = ns_stat,
+        .fstat        = ns_fstat,
+        .truncate     = ns_truncate,
+        .ftruncate    = ns_ftruncate,
+        .access       = ns_access,
+        .readlink     = ns_readlink,
+        .mknod        = ns_mknod,
+        .mkdir        = ns_mkdir,
+        .unlink       = ns_unlink,
+        .rmdir        = ns_rmdir,
+        .symlink      = ns_symlink,
+        .rename       = ns_rename,
+        .link         = ns_link,
+        .create       = ns_create,
+        .open         = ns_open,
+        .readv        = ns_readv,
+        .writev       = ns_writev,
+        .flush        = ns_flush,
+        .fsync        = ns_fsync,
+        .opendir      = ns_opendir,
+        .readdir      = ns_readdir,
+        .readdirp     = ns_readdirp,
+        .fsyncdir     = ns_fsyncdir,
+        .statfs       = ns_statfs,
+        .setxattr     = ns_setxattr,
+        .getxattr     = ns_getxattr,
+        .fsetxattr    = ns_fsetxattr,
+        .fgetxattr    = ns_fgetxattr,
+        .removexattr  = ns_removexattr,
+        .fremovexattr = ns_fremovexattr,
+        .lk           = ns_lk,
+        .inodelk      = ns_inodelk,
+        .finodelk     = ns_finodelk,
+        .entrylk      = ns_entrylk,
+        .fentrylk     = ns_fentrylk,
+        .rchecksum    = ns_rchecksum,
+        .xattrop      = ns_xattrop,
+        .fxattrop     = ns_fxattrop,
+        .setattr      = ns_setattr,
+        .fsetattr     = ns_fsetattr,
+        .getspec      = ns_getspec,
+        .fallocate    = ns_fallocate,
+        .discard      = ns_discard,
+        .zerofill     = ns_zerofill,
+};
+
+struct xlator_cbks cbks = {
+        .forget = ns_forget,
+};
+
+struct xlator_dumpops dumpops;
+
+struct volume_options options[] = {
+        {
+        .key           = { "tag-namespaces" },
+        .type          = GF_OPTION_TYPE_BOOL,
+        .default_value = "off",
+        .description   = "This option enables this translator's functionality "
+                       "that tags every fop with a namespace hash for later "
+                       "throttling, stats collection, logging, etc.",
+        .op_version    = {GD_OP_VERSION_4_1_0},
+        .tags          = {"namespace"},
+        .flags         = OPT_FLAG_SETTABLE | OPT_FLAG_CLIENT_OPT | OPT_FLAG_DOC,
+        },
+        {.key = { NULL } },
+};
diff --git a/xlators/features/namespace/src/namespace.h b/xlators/features/namespace/src/namespace.h
new file mode 100644
index 00000000000..1dbec50e024
--- /dev/null
+++ b/xlators/features/namespace/src/namespace.h
@@ -0,0 +1,23 @@
+#ifndef __NAMESPACE_H__
+#define __NAMESPACE_H__
+
+#ifndef _CONFIG_H
+#define _CONFIG_H
+#include "config.h"
+#endif
+
+#include "xlator.h"
+#include "call-stub.h"
+
+#define GF_NAMESPACE "namespace"
+
+typedef struct {
+        gf_boolean_t tag_namespaces;
+} ns_private_t;
+
+typedef struct {
+        loc_t loc;         /* We store a "fake" loc_t for the getxattr wind. */
+        call_stub_t *stub; /* A stub back to the function we're resuming. */
+} ns_local_t;
+
+#endif /* __NAMESPACE_H__ */