dht: block/handle create op falling to decommissioned brick

Problem:
Post remove-brick start till commit phase, the client layout
may not be in sync with disk layout because of lack of lookup.
Hence,a create call may fall on the decommissioned brick.

Solution:
Will acquire a lock on hashed subvol. So that a fix-layout or
selfheal can not step on layout while reading the layout.

Even if we read a layout before remove-brick fix-layout and the
file falls on the decommissioned brick, the file should be
migrated to a new brick as per the fix-layout.

BUG: 1256283
Change-Id: I3ef1adaf20dfb9524396a3648d1a664464eda8c1
Signed-off-by: Susant Palai <spalai@redhat.com>
Reviewed-on: http://review.gluster.org/11260
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Reviewed-by: Raghavendra G <rgowdapp@redhat.com>
Signed-off-by: Susant Palai <spalai@redhat.com>
Reviewed-on: http://review.gluster.org/12001

1 files changed, 15 insertions, 3 deletions

diff --git a/xlators/cluster/dht/src/dht-selfheal.c b/xlators/cluster/dht/src/dht-selfheal.c
index cfe7e5a63ce..cd1d97f7fc0 100644
--- a/xlators/cluster/dht/src/dht-selfheal.c
+++ b/xlators/cluster/dht/src/dht-selfheal.c
@@ -214,7 +214,7 @@ unlock:
 
         if (is_last_call (this_call_cnt)) {
                 if (local->op_ret == 0) {
-                        dht_refresh_layout_done (frame);
+                        local->refresh_layout_done (frame);
                 } else {
                         goto err;
                 }
@@ -224,7 +224,8 @@ unlock:
         return 0;
 
 err:
-        dht_selfheal_dir_finish (frame, this, -1);
+        local->refresh_layout_unlock (frame, this, -1);
+
         return 0;
 }
 
@@ -290,7 +291,7 @@ dht_refresh_layout (call_frame_t *frame)
         return 0;
 
 out:
-        dht_selfheal_dir_finish (frame, this, -1);
+        local->refresh_layout_unlock (frame, this, -1);
         return 0;
 }
 
@@ -299,10 +300,21 @@ int32_t
 dht_selfheal_layout_lock_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
                               int32_t op_ret, int32_t op_errno, dict_t *xdata)
 {
+        dht_local_t     *local = NULL;
+
+        local = frame->local;
+
+        if (!local) {
+                goto err;
+        }
+
         if (op_ret < 0) {
                 goto err;
         }
 
+        local->refresh_layout_unlock = dht_selfheal_dir_finish;
+        local->refresh_layout_done = dht_refresh_layout_done;
+
         dht_refresh_layout (frame);
         return 0;