tier/gfdb : Round-Robin read of query files

1. Each brick on a host will get a separate query file.
2. While reading query record from these query files we
   read them in a Round-Robin manner.
3. When an error occurs during migration we rename it to
   query file with an time stamp and .err extension for
   better debugging.

Change-Id: I27c4285d24fd695d2d5cbd9fd7db3879d277ecc8
BUG: 1302772
Signed-off-by: Joseph Fernandes <josferna@redhat.com>
Reviewed-on: http://review.gluster.org/13293
Smoke: Gluster Build System <jenkins@build.gluster.com>
Tested-by: N Balachandran <nbalacha@redhat.com>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
Reviewed-by: Dan Lambright <dlambrig@redhat.com>
CentOS-regression: Gluster Build System <jenkins@build.gluster.com>

1 files changed, 20 insertions, 6 deletions

diff --git a/xlators/cluster/dht/src/tier.h b/xlators/cluster/dht/src/tier.h
index 92e2fda6e5c..41c5a318de4 100644
--- a/xlators/cluster/dht/src/tier.h
+++ b/xlators/cluster/dht/src/tier.h
@@ -39,25 +39,39 @@
 #define GET_QFILE_PATH(is_promotion)\
         (is_promotion) ? promotion_qfile : demotion_qfile
 
+typedef struct tier_qfile_array {
+        int             *fd_array;
+        ssize_t         array_size;
+        ssize_t         next_index;
+        /* Indicate the number of exhuasted FDs*/
+        ssize_t         exhausted_count;
+} tier_qfile_array_t;
+
+
 typedef struct _query_cbk_args {
-        xlator_t *this;
-        gf_defrag_info_t *defrag;
-        int query_fd;
-        int is_promotion;
+        xlator_t                *this;
+        gf_defrag_info_t        *defrag;
+        /* This is write */
+        int                     query_fd;
+        int                     is_promotion;
+        /* This is for read */
+        tier_qfile_array_t       *qfile_array;
 } query_cbk_args_t;
 
 int
 gf_run_tier(xlator_t *this, gf_defrag_info_t *defrag);
 
 typedef struct gfdb_brick_info {
-        gfdb_time_t           *time_stamp;
+        gfdb_time_t             *time_stamp;
         gf_boolean_t            _gfdb_promote;
-        query_cbk_args_t       *_query_cbk_args;
+        query_cbk_args_t        *_query_cbk_args;
 } gfdb_brick_info_t;
 
 typedef struct brick_list {
         xlator_t          *xlator;
         char              *brick_db_path;
+        char              brick_name[NAME_MAX];
+        char              qfile_path[PATH_MAX];
         struct list_head  list;
 } tier_brick_list_t;