tier/libgfdb: Replacing ASCII query file with binary

Earlier, when the database was queried we used to save
all the queried records in an ASCII format in the query file.
This caused issues like filename having ASCII delimiter and used
to take a lot of space. The tier.c file also had a lot of parsing code.

Here we changed the format of the query file to binary.
All the logic of serialization and formating of query record is done
by libgfdb. Libgfdb provides API,
gfdb_write_query_record() and gfdb_read_query_record(),
which the user i.e tier migrator and CTR xlator can use to
write to and read from query file.
With this binary format we save on disk space i.e reduce to 50% atleast
as we are saving GFID's in binary format 16 bytes and not the string format
which takes 36 bytes + We are not saving path of the file + we are also saving on
ASCII delimiters.

The on disk format of query record is as follows,

+---------------------------------------------------------------------------+
| Length of serialized query record |       Serialized Query Record         |
+---------------------------------------------------------------------------+
             4 bytes                     Length of serialized query record
                                                      |
                                                      |
     -------------------------------------------------|
     |
     |
     V
   Serialized Query Record Format:
   +---------------------------------------------------------------------------+
   | GFID |  Link count   |  <LINK INFO>  |.....                      | FOOTER |
   +---------------------------------------------------------------------------+
     16 B        4 B         Link Length                                  4 B
                                |                                          |
                                |                                          |
   -----------------------------|                                          |
   |                                                                       |
   |                                                                       |
   V                                                                       |
   Each <Link Info> will be serialized as                                  |
   +-----------------------------------------------+                       |
   | PGID | BASE_NAME_LENGTH |      BASE_NAME      |                       |
   +-----------------------------------------------+                       |
     16 B       4 B             BASE_NAME_LENGTH                           |
                                                                           |
                                                                           |
   ------------------------------------------------------------------------|
   |
   |
   V
   FOOTER is a magic number 0xBAADF00D indicating the end of the record.
   This also serves as a serialized schema validator.

Backport of http://review.gluster.org/#/c/12354/

> Change-Id: I9db7416fd421e118dd44eafab8b535caafe50d5a
> BUG: 1272207
> Signed-off-by: Joseph Fernandes <josferna@redhat.com>
> Reviewed-on: http://review.gluster.org/12354
> Reviewed-by: N Balachandran <nbalacha@redhat.com>
> Tested-by: Gluster Build System <jenkins@build.gluster.com>
> Reviewed-by: Dan Lambright <dlambrig@redhat.com>
> Tested-by: Dan Lambright <dlambrig@redhat.com>

Change-Id: I170c579027f2594a58706f826e3ddf89e34022f4
BUG: 1263619
Signed-off-by: Joseph Fernandes <josferna@redhat.com>
Reviewed-on: http://review.gluster.org/12535
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Dan Lambright <dlambrig@redhat.com>
Tested-by: Dan Lambright <dlambrig@redhat.com>

1 files changed, 15 insertions, 1 deletions

diff --git a/libglusterfs/src/gfdb/gfdb_data_store.h b/libglusterfs/src/gfdb/gfdb_data_store.h
index 58a942c2d39..44fdef09b25 100644
--- a/libglusterfs/src/gfdb/gfdb_data_store.h
+++ b/libglusterfs/src/gfdb/gfdb_data_store.h
@@ -279,6 +279,8 @@ typedef int (*find_recently_changed_files_freq_t) (gfdb_conn_node_t *_conn_node,
                                                    gf_boolean_t _clear_counters);
 
 
+typedef const
+char *(*get_db_path_key_t)();
 
 /*Libgfdb API Function: Clear the heat for all the files
  *
@@ -349,7 +351,19 @@ typedef struct gfdb_methods_s {
         /* Do not expose dbpath directly. Expose it via an */
         /* access function: get_db_path_key(). */
         char *dbpath;
-        get_db_path_t get_db_path_key;
+        get_db_path_key_t get_db_path_key;
+
+        /* Query Record related functions */
+        gfdb_query_record_new_t gfdb_query_record_new;
+        gfdb_query_record_free_t gfdb_query_record_free;
+        gfdb_add_link_to_query_record_t gfdb_add_link_to_query_record;
+        gfdb_write_query_record_t gfdb_write_query_record;
+        gfdb_read_query_record_t gfdb_read_query_record;
+
+        /* Link info related functions */
+        gfdb_link_info_new_t gfdb_link_info_new;
+        gfdb_link_info_free_t gfdb_link_info_free;
+
 } gfdb_methods_t;
 
 void get_gfdb_methods (gfdb_methods_t *methods);