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, 11 insertions, 0 deletions

diff --git a/xlators/cluster/dht/src/dht-common.h b/xlators/cluster/dht/src/dht-common.h
index 5e86b32263c..f583d30599d 100644
--- a/xlators/cluster/dht/src/dht-common.h
+++ b/xlators/cluster/dht/src/dht-common.h
@@ -44,6 +44,10 @@ typedef int (*dht_selfheal_dir_cbk_t) (call_frame_t *frame, void *cookie,
 typedef int (*dht_defrag_cbk_fn_t) (xlator_t        *this, xlator_t *dst_node,
                                     call_frame_t    *frame);
 
+typedef int (*dht_refresh_layout_unlock) (call_frame_t *frame, xlator_t *this,
+                                         int op_ret);
+
+typedef int (*dht_refresh_layout_done_handle) (call_frame_t *frame);
 
 struct dht_layout {
         int                spread_cnt;  /* layout spread count per directory,
@@ -212,6 +216,10 @@ struct dht_local {
                 gf_boolean_t            force_mkdir;
                 dht_layout_t           *layout, *refreshed_layout;
         } selfheal;
+
+        dht_refresh_layout_unlock              refresh_layout_unlock;
+        dht_refresh_layout_done_handle         refresh_layout_done;
+
         uint32_t                 uid;
         uint32_t                 gid;
 
@@ -510,6 +518,7 @@ typedef struct dht_migrate_info {
         GF_REF_DECL;
 } dht_migrate_info_t;
 
+
 #define ENTRY_MISSING(op_ret, op_errno) (op_ret == -1 && op_errno == ENOENT)
 
 #define is_revalidate(loc) (dht_inode_ctx_layout_get (loc->inode, this, NULL) == 0)
@@ -1067,4 +1076,6 @@ dht_layout_sort (dht_layout_t *layout);
 int
 dht_layout_missing_dirs (dht_layout_t *layout);
 
+int
+dht_refresh_layout (call_frame_t *frame);
 #endif/* _DHT_H */