meta: (re-)Implement Meta translator

The meta translator exposes details about glusterfs itself
in the form of a virtual namespace.

Loading the translator on the client side creates the
meta virtual view under $mntpoint/.meta by default. The
directory is not listed (even with ls -a) and can be
accessed by doing a "cd /mnt/.meta"

Change-Id: I5ffdf39203841a9562a8280a1f79dc76d4dded5d
BUG: 1089216
Signed-off-by: Anand Avati <avati@redhat.com>
Reviewed-on: http://review.gluster.org/7509
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Harshavardhana <harsha@harshavardhana.net>

1 files changed, 370 insertions, 0 deletions

diff --git a/xlators/meta/src/meta-helpers.c b/xlators/meta/src/meta-helpers.c
new file mode 100644
index 00000000000..a67671050b8
--- /dev/null
+++ b/xlators/meta/src/meta-helpers.c
@@ -0,0 +1,370 @@
+/*
+   Copyright (c) 2014 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.
+*/
+
+#ifndef _CONFIG_H
+#define _CONFIG_H
+#include "config.h"
+#endif
+
+#include "xlator.h"
+#include "defaults.h"
+
+#include "meta-mem-types.h"
+#include "meta.h"
+
+
+meta_fd_t *
+meta_fd_get (fd_t *fd, xlator_t *this)
+{
+	uint64_t value = 0;
+	meta_fd_t *meta_fd = NULL;
+
+	LOCK (&fd->lock);
+	{
+		__fd_ctx_get (fd, this, &value);
+		if (!value) {
+			meta_fd = GF_CALLOC (1, sizeof (*meta_fd),
+					     gf_meta_mt_fd_t);
+			if (!meta_fd)
+				goto unlock;
+
+			value = (long) meta_fd;
+			__fd_ctx_set (fd, this, value);
+		}
+
+		meta_fd = (void *) value;
+	}
+unlock:
+	UNLOCK (&fd->lock);
+
+	return meta_fd;
+}
+
+
+int
+meta_fd_release (fd_t *fd, xlator_t *this)
+{
+	uint64_t value = 0;
+	meta_fd_t *meta_fd = NULL;
+	int i = 0;
+
+	fd_ctx_get (fd, this, &value);
+	meta_fd = (void *) value;
+
+	if (meta_fd->dirents) {
+		for (i = 0; i < meta_fd->size; i++)
+			GF_FREE ((void *)meta_fd->dirents[i].name);
+		GF_FREE (meta_fd->dirents);
+	}
+
+	if (meta_fd) {
+		GF_FREE (meta_fd->data);
+		GF_FREE (meta_fd);
+	}
+	return 0;
+}
+
+
+struct meta_ops *
+meta_ops_get (inode_t *inode, xlator_t *this)
+{
+	struct meta_ops *ops = NULL;
+	uint64_t value = 0;
+
+	inode_ctx_get2 (inode, this, NULL, &value);
+
+	ops = (void *) value;
+
+	return ops;
+}
+
+
+struct xlator_fops *
+meta_fops_get (inode_t *inode, xlator_t *this)
+{
+	struct meta_ops *ops = NULL;
+
+	ops = meta_ops_get (inode, this);
+	if (!ops)
+		return default_fops;
+
+	return &ops->fops;
+}
+
+
+int
+meta_ops_set (inode_t *inode, xlator_t *this, struct meta_ops *ops)
+{
+	uint64_t value = 0;
+	int ret = 0;
+
+	meta_defaults_init (&ops->fops);
+
+	value = (long) ops;
+
+	ret = inode_ctx_set2 (inode, this, NULL, &value);
+
+	return ret;
+}
+
+void *
+meta_ctx_get (inode_t *inode, xlator_t *this)
+{
+	void *ctx = NULL;
+	uint64_t value = 0;
+
+	inode_ctx_get2 (inode, this, &value, 0);
+
+	ctx = (void *) value;
+
+	return ctx;
+}
+
+
+int
+meta_ctx_set (inode_t *inode, xlator_t *this, void *ctx)
+{
+	uint64_t value = 0;
+	int ret = 0;
+
+	value = (long) ctx;
+
+	ret = inode_ctx_set2 (inode, this, &value, 0);
+
+	return ret;
+}
+
+
+void
+meta_local_cleanup (meta_local_t *local, xlator_t *this)
+{
+	if (!local)
+		return;
+
+	if (local->xdata)
+		dict_unref (local->xdata);
+
+	GF_FREE (local);
+	return;
+}
+
+
+meta_local_t *
+meta_local (call_frame_t *frame)
+{
+	meta_local_t *local = NULL;
+
+	local = frame->local;
+	if (!local)
+		local = frame->local = GF_CALLOC (1, sizeof(*local),
+						  gf_meta_mt_local_t);
+	return local;
+}
+
+
+dict_t *
+meta_direct_io_mode (dict_t *xdata, call_frame_t *frame)
+{
+	meta_local_t *local = NULL;
+
+	if (!xdata) {
+		local = meta_local (frame);
+		if (!local)
+			return NULL;
+		xdata = local->xdata = dict_new();
+		if (!xdata)
+			return NULL;
+	}
+
+	if (dict_set_int8 (xdata, "direct-io-mode", 1) != 0)
+		return NULL;
+
+	return xdata;
+}
+
+
+static uint64_t
+gfid_to_ino (uuid_t gfid)
+{
+        uint64_t  ino = 0;
+        int       i = 0, j = 0;
+
+        for (i = 15; i > (15 - 8); i--) {
+                ino += (uint64_t)(gfid[i]) << j;
+                j += 8;
+        }
+
+        return ino;
+}
+
+
+static void
+meta_uuid_copy (uuid_t dst, uuid_t src)
+{
+	uuid_copy (dst, src);
+	if (uuid_is_null (dst))
+		uuid_generate (dst);
+}
+
+
+static void
+default_meta_iatt_fill (struct iatt *iatt, inode_t *inode, ia_type_t type)
+{
+	struct timeval tv = { };
+
+	iatt->ia_type = type;
+	switch (type)
+	{
+	case IA_IFDIR:
+		iatt->ia_prot = ia_prot_from_st_mode (0755);
+		iatt->ia_nlink = 2;
+		break;
+	case IA_IFLNK:
+		iatt->ia_prot = ia_prot_from_st_mode (0777);
+		iatt->ia_nlink = 1;
+		break;
+	default:
+		iatt->ia_prot = ia_prot_from_st_mode (0644);
+		iatt->ia_nlink = 1;
+		break;
+	}
+	iatt->ia_uid = 0;
+	iatt->ia_gid = 0;
+	iatt->ia_size = 0;
+
+	meta_uuid_copy (iatt->ia_gfid, inode->gfid);
+	iatt->ia_ino = gfid_to_ino (iatt->ia_gfid);
+
+	gettimeofday (&tv, 0);
+	iatt->ia_mtime = iatt->ia_ctime = iatt->ia_atime = tv.tv_sec;
+	iatt->ia_mtime_nsec = iatt->ia_ctime_nsec = iatt->ia_atime_nsec =
+		(tv.tv_usec * 1000);
+	return;
+}
+
+
+void
+meta_iatt_fill (struct iatt *iatt, inode_t *inode, ia_type_t type)
+{
+	struct meta_ops *ops = NULL;
+
+	ops = meta_ops_get (inode, THIS);
+	if (!ops)
+		return;
+
+	if (!ops->iatt_fill)
+		default_meta_iatt_fill (iatt, inode, type);
+	else
+		ops->iatt_fill (THIS, inode, iatt);
+	return;
+}
+
+
+int
+meta_inode_discover (call_frame_t *frame, xlator_t *this, loc_t *loc,
+		     dict_t *xdata)
+{
+	struct iatt iatt = { };
+	struct iatt postparent = { };
+
+	meta_iatt_fill (&iatt, loc->inode, loc->inode->ia_type);
+
+	META_STACK_UNWIND (lookup, frame, 0, 0, loc->inode, &iatt, xdata,
+			   &postparent);
+	return 0;
+}
+
+
+int
+meta_file_fill (xlator_t *this, fd_t *fd)
+{
+	meta_fd_t *meta_fd = NULL;
+	strfd_t *strfd = NULL;
+	struct meta_ops *ops = NULL;
+	int ret = 0;
+
+	meta_fd = meta_fd_get (fd, this);
+	if (!meta_fd)
+		return -1;
+
+	if (meta_fd->data)
+		return meta_fd->size;
+
+	strfd = strfd_open ();
+	if (!strfd)
+		return -1;
+
+	ops = meta_ops_get (fd->inode, this);
+	if (!ops) {
+		strfd_close (strfd);
+		return -1;
+	}
+
+	if (ops->file_fill)
+		ret = ops->file_fill (this, fd->inode, strfd);
+
+	if (ret >= 0) {
+		meta_fd->data = strfd->data;
+		meta_fd->size = strfd->size;
+
+		strfd->data = NULL;
+	}
+
+	strfd_close (strfd);
+
+	return meta_fd->size;
+}
+
+
+int
+meta_dir_fill (xlator_t *this, fd_t *fd)
+{
+	meta_fd_t *meta_fd = NULL;
+	struct meta_ops *ops = NULL;
+	struct meta_dirent *dp = NULL;
+	int ret = 0;
+
+	meta_fd = meta_fd_get (fd, this);
+	if (!meta_fd)
+		return -1;
+
+	if (meta_fd->dirents)
+		return meta_fd->size;
+
+	ops = meta_ops_get (fd->inode, this);
+	if (!ops)
+		return -1;
+
+	if (ops->dir_fill)
+		ret = ops->dir_fill (this, fd->inode, &dp);
+
+	if (dp) {
+		meta_fd->dirents = dp;
+		meta_fd->size = ret;
+	}
+
+	return meta_fd->size;
+}
+
+
+int
+fixed_dirents_len (struct meta_dirent *dirents)
+{
+	int i = 0;
+	struct meta_dirent *dirent = NULL;
+
+	if (!dirents)
+		return 0;
+
+	for (dirent = dirents; dirent->name; dirent++)
+		i++;
+
+	return i;
+}