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, 103 insertions, 16 deletions

diff --git a/xlators/meta/src/meta.h b/xlators/meta/src/meta.h
index 73e0e50db57..f6ec8cb9cb7 100644
--- a/xlators/meta/src/meta.h
+++ b/xlators/meta/src/meta.h
@@ -1,5 +1,5 @@
 /*
-   Copyright (c) 2006-2012 Red Hat, Inc. <http://www.redhat.com>
+   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
@@ -15,24 +15,111 @@
 #include "config.h"
 #endif
 
-struct _meta_dirent {
-  const char *name;
-  int type;
-  struct _meta_dirent *children;
-  struct _meta_dirent *parent;
-  struct _meta_dirent *next;
-  struct stat *stbuf;
-  xlator_t *view_xlator;
-  struct xlator_fops *fops;
+#include "strfd.h"
+
+#define DEFAULT_META_DIR_NAME ".meta"
+
+#define META_ROOT_GFID "ba926388-bb9c-4eec-ad60-79dba4cc083a"
+
+#define IS_META_ROOT_GFID(g) (strcmp (uuid_utoa(g), META_ROOT_GFID) == 0)
+
+typedef int (*meta_hook_t) (call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *xdata);
+
+typedef struct {
+	dict_t *xdata;
+} meta_local_t;
+
+typedef struct {
+	char *meta_dir_name;
+} meta_priv_t;
+
+struct meta_dirent {
+	const char *name;
+	ia_type_t type;
+	meta_hook_t hook;
+};
+
+#define DOT_DOTDOT { .name = ".", .type = IA_IFDIR }, { .name = "..", .type = IA_IFDIR }
+
+struct meta_ops {
+	struct meta_dirent *fixed_dirents;
+	int (*dir_fill) (xlator_t *this, inode_t *dir, struct meta_dirent **entries);
+	int (*file_fill) (xlator_t *this, inode_t *file, strfd_t *strfd);
+	int (*iatt_fill) (xlator_t *this, inode_t *inode, struct iatt *iatt);
+	int (*link_fill) (xlator_t *this, inode_t *inode, strfd_t *strfd);
+	struct xlator_fops fops;
+	struct xlator_cbks cbks;
 };
-typedef struct _meta_dirent meta_dirent_t;
 
 typedef struct {
-  const char *directory;
-  meta_dirent_t *tree;
-} meta_private_t;
+	char *data;
+	struct meta_dirent *dirents;
+	size_t size;
+} meta_fd_t;
+
+
+#define COUNT(arr) (sizeof(arr)/sizeof(arr[0]))
+
+#define META_HOOK(loc) (__is_root_gfid (loc->pargfid) && !strcmp (loc->name, META_PRIV(THIS)->meta_dir_name))
+
+#define META_PRIV(t) ((meta_priv_t *)(t->private))
+
+#define META_STACK_UNWIND(fop, frame, params ...)		\
+        do {                                                    \
+                meta_local_t *__local = NULL;			\
+                xlator_t    *__this = NULL;                     \
+                if (frame) {                                    \
+                        __local = frame->local;                 \
+                        __this = frame->this;                   \
+                        frame->local = NULL;                    \
+                }                                               \
+                STACK_UNWIND_STRICT (fop, frame, params);       \
+                if (__local) {                                  \
+                        meta_local_cleanup (__local, __this);	\
+                }                                               \
+        } while (0)
+
+
+#define META_FOP(i, fop, fr, t, params ...) {	\
+	struct xlator_fops *_fops = NULL;	\
+						\
+	_fops = meta_fops_get (i, t);		\
+						\
+	_fops->fop (fr, t, params);		\
+	} while (0)
+
+
+void meta_iatt_fill (struct iatt *iatt, inode_t *inode, ia_type_t type);
+
+int meta_inode_discover (call_frame_t *frame, xlator_t *this, loc_t *loc,
+			 dict_t *xdata);
+
+int meta_ops_set (inode_t *inode, xlator_t *this, struct meta_ops *ops);
+
+struct xlator_fops *meta_fops_get (inode_t *inode, xlator_t *this);
+struct xlator_cbks *meta_cbks_get (inode_t *inode, xlator_t *this);
+struct meta_ops *meta_ops_get (inode_t *inode, xlator_t *this);
+
+int meta_ctx_set (inode_t *inode, xlator_t *this, void *ctx);
+
+void *meta_ctx_get (inode_t *inode, xlator_t *this);
+
+
+void meta_local_cleanup (meta_local_t *local, xlator_t *this);
+
+struct xlator_fops *meta_defaults_init (struct xlator_fops *fops);
+
+meta_fd_t *meta_fd_get (fd_t *fd, xlator_t *this);
+
+int meta_fd_release (fd_t *fd, xlator_t *this);
+
+dict_t *meta_direct_io_mode (dict_t *xdata, call_frame_t *frame);
+
+meta_local_t *meta_local (call_frame_t *frame);
+
+int meta_file_fill (xlator_t *this, fd_t *fd);
 
-#include "tree.h"
-#include "misc.h"
+int meta_dir_fill (xlator_t *this, fd_t *fd);
 
+int fixed_dirents_len (struct meta_dirent *dirents);
 #endif /* __META_H__ */