cluster/afr: Make local->child_up immutable

Afr transaction performs lock, pre-op, op, post-op and unlock steps in that
order. The child_up[] is overloaded with the information of where all
the first two steps succeeded. This works perfectly fine for
Transaction, but the locking/unlocking part of the code is re-used by
data self-heal. In that each loop_frame does lock, rchecksum,
read-from-source and write-to-sinks, unlock steps.

Rchecksum fop assumes that the fop needs to happen on one source + all
sinks and sets the call_count to that number. But if the lock step fails
on any of the sinks it will mark the child_up of that child to 0, which
will result in call_count mismatch and the frame will hang thinking that
some more cbks need to come. When this happens loop_frame will never go
to unlock step leading to hangs on that file.

Change-Id: I3dd0449cc6193a980bacf637d935881f4b22210a
BUG: 3597
Reviewed-on: http://review.gluster.com/474
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Amar Tumballi <amar@gluster.com>
Reviewed-by: Vijay Bellur <vijay@gluster.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/xlators/cluster/afr/src/afr.h b/xlators/cluster/afr/src/afr.h
index 92ccf607f10..becbd261f57 100644
--- a/xlators/cluster/afr/src/afr.h
+++ b/xlators/cluster/afr/src/afr.h
@@ -377,7 +377,7 @@ typedef struct _afr_local {
         loc_t newloc;
 
         fd_t *fd;
-        int32_t *fd_open_on;
+        unsigned char *fd_open_on;
 
         glusterfs_fop_t fop;
 
@@ -682,6 +682,7 @@ typedef struct _afr_local {
 
                 int last_tried;
                 int32_t *child_errno;
+                unsigned char   *pre_op;
 
                 call_frame_t *main_frame;
 
@@ -826,6 +827,10 @@ afr_up_children_count (unsigned char *child_up, unsigned int child_count);
 unsigned int
 afr_locked_children_count (unsigned char *children, unsigned int child_count);
 
+unsigned int
+afr_pre_op_done_children_count (unsigned char *pre_op,
+                                unsigned int child_count);
+
 gf_boolean_t
 afr_is_fresh_lookup (loc_t *loc, xlator_t *this);