gfid: introduce uuid based handles for inodes

gfid represents a gluter file id. This is a universally unique id
assigned to a logical inode, independent of the inode numbers
assigned by the various backend filesystems to that file/directory.
The gfid of a file/directory will be the same on servers depending
on the cluster translator in picture.

  The same gfid can be used as a handle across layers of various
translators and across servers and clients. This was not the case
previously as the cluster translators would pick the backend inode
number from one of the servers and convert that into a logical
inode number by performing some mathematical transforms.

  This new technique of addressing inodes also makes dynamic volume
management have a more robust implementation as the file handles
remain the same on all versions of the graphs, and allows for
seamless NFS daemon restarts as well.

  This change makes way for server originating communication which
was not possible earlier as the servers did not have any reliable
way of addressing client side inodes at all. gfid solves this problem
by preserving the same uuid as the handle on all the servers and
across all clients

Signed-off-by: Anand V. Avati <avati@blackhole.gluster.com>
Signed-off-by: Anand V. Avati <avati@amp.gluster.com>
Signed-off-by: Vijay Bellur <vijay@dev.gluster.com>

BUG: 971 (dynamic volume management)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=971

4 files changed, 8 insertions, 1 deletions

diff --git a/configure.ac b/configure.ac
index b2cad35de74..cdeadb2b1c8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -422,6 +422,9 @@ AC_SUBST(RLLIBS)
 CONTRIBDIR='$(top_srcdir)/contrib'
 AC_SUBST(CONTRIBDIR)
 
+INCLUDES='-I$(top_srcdir)/libglusterfs/src -I$(CONTRIBDIR)/uuid'
+AC_SUBST(INCLUDES)
+
 AM_CONDITIONAL([GF_DARWIN_HOST_OS], test "${GF_HOST_OS}" = "GF_DARWIN_HOST_OS")	
 
 AC_OUTPUT
diff --git a/libglusterfs/src/Makefile.am b/libglusterfs/src/Makefile.am
index f6c2cf8555b..3513419ebc9 100644
--- a/libglusterfs/src/Makefile.am
+++ b/libglusterfs/src/Makefile.am
@@ -1,6 +1,6 @@
 libglusterfs_la_CFLAGS = -fPIC  -Wall -g -shared -nostartfiles $(GF_CFLAGS) $(GF_DARWIN_LIBGLUSTERFS_CFLAGS)
 
-libglusterfs_la_CPPFLAGS = -D_FILE_OFFSET_BITS=64 -D__USE_FILE_OFFSET64 -D_GNU_SOURCE -DXLATORDIR=\"$(libdir)/glusterfs/$(PACKAGE_VERSION)/xlator\" -D$(GF_HOST_OS) -I$(CONTRIBDIR)/rbtree  -DSCHEDULERDIR=\"$(libdir)/glusterfs/$(PACKAGE_VERSION)/scheduler\" -I$(CONTRIBDIR)/md5 -I$(CONTRIBDIR)/uuid
+libglusterfs_la_CPPFLAGS = -D_FILE_OFFSET_BITS=64 -D__USE_FILE_OFFSET64 -D_GNU_SOURCE -DXLATORDIR=\"$(libdir)/glusterfs/$(PACKAGE_VERSION)/xlator\" -D$(GF_HOST_OS) -I$(CONTRIBDIR)/rbtree  -DSCHEDULERDIR=\"$(libdir)/glusterfs/$(PACKAGE_VERSION)/scheduler\" -I$(CONTRIBDIR)/md5
 
 libglusterfs_la_LIBADD = @LEXLIB@
 
diff --git a/libglusterfs/src/iatt.h b/libglusterfs/src/iatt.h
index ef64f9afc95..e67d714c2a7 100644
--- a/libglusterfs/src/iatt.h
+++ b/libglusterfs/src/iatt.h
@@ -31,6 +31,7 @@
 #include <unistd.h>
 
 #include "compat.h"
+#include "uuid.h"
 
 typedef enum {
         IA_INVAL = 0,
@@ -59,6 +60,7 @@ typedef struct {
 struct iatt {
         uint64_t     ia_ino;        /* inode number */
         uint64_t     ia_gen;        /* generation number */
+        uuid_t       ia_gfid;
         uint64_t     ia_dev;        /* backing device ID */
         ia_type_t    ia_type;       /* type of file */
         ia_prot_t    ia_prot;       /* protection */
diff --git a/libglusterfs/src/inode.h b/libglusterfs/src/inode.h
index 18081b8f8ce..a0bb8f8b57d 100644
--- a/libglusterfs/src/inode.h
+++ b/libglusterfs/src/inode.h
@@ -40,6 +40,7 @@ typedef struct _dentry dentry_t;
 #include "list.h"
 #include "xlator.h"
 #include "iatt.h"
+#include "uuid.h"
 
 
 struct _inode_table {
@@ -94,6 +95,7 @@ struct _inode_ctx {
 
 struct _inode {
         inode_table_t       *table;         /* the table this inode belongs to */
+        uuid_t               gfid;
         gf_lock_t            lock;
         uint64_t             nlookup;
         uint64_t             generation;