cluster/afr: Avoid order mismatch in blocking entrylks

Problem:
When taking blocking entrylks, afr orders the entrylks based on
uuid_compare of gfids of parent dirs, if they are equal then it orders
them based on the basenames. While this approach works fine, the
implementation assumes loc->gfids to be populated at the time of
the comparison, but loc may have gfid in loc->inode->gfid instead
of loc->gfid which was leading to order mismatches and dead-locks.

Fix:
Implemented loc_gfid which gives gfid by checking both loc->gfid,
loc->inode->gfid. Used this for ordering the blocking entrylks.

Change-Id: Ib0db36bbaf0df09fa87c3c3bb6a834db74fc2154
BUG: 965987
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/5062
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

1 files changed, 9 insertions, 6 deletions

diff --git a/xlators/cluster/afr/src/afr-lk-common.c b/xlators/cluster/afr/src/afr-lk-common.c
index e091a7939fe..812609819f5 100644
--- a/xlators/cluster/afr/src/afr-lk-common.c
+++ b/xlators/cluster/afr/src/afr-lk-common.c
@@ -57,11 +57,15 @@
 int
 afr_entry_lockee_cmp (const void *l1, const void *l2)
 {
-       const afr_entry_lockee_t       *r1 = l1;
-       const afr_entry_lockee_t       *r2 = l2;
-       int                            ret = 0;
-
-        ret = uuid_compare (r1->loc.gfid, r2->loc.gfid);
+        const afr_entry_lockee_t       *r1 = l1;
+        const afr_entry_lockee_t       *r2 = l2;
+        int                            ret = 0;
+        uuid_t                         gfid1 = {0};
+        uuid_t                         gfid2 = {0};
+
+        loc_gfid ((loc_t*)&r1->loc, gfid1);
+        loc_gfid ((loc_t*)&r2->loc, gfid2);
+        ret = uuid_compare (gfid1, gfid2);
         /*Entrylks with NULL basename are the 'smallest'*/
         if (ret == 0) {
                 if (!r1->basename)
@@ -75,7 +79,6 @@ afr_entry_lockee_cmp (const void *l1, const void *l2)
                 return -1;
         else
                 return 1;
-
 }
 
 int afr_lock_blocking (call_frame_t *frame, xlator_t *this, int child_index);