cluster/dht: pass a destination subvol to fop2 variants to avoid races.

The destination subvol used in the fop2 variants is either stored in
inode-ctx1 or local->cached_subvol. However, it is not guaranteed that
a value stored in these locations before invocation of fop2 is still
present after the invocation as these locations are shared among
different concurrent operations. So, to preserve the atomicity of
"check dst-subvol and invoke fop2 variant if dst-subvol found", we
pass down the dst-subvol to fop2 variant.

This patch also fixes error handling in some fop2 variants.

Change-Id: Icc226228a246d3f223e3463519736c4495b364d2
BUG: 1225809
Signed-off-by: Raghavendra G <rgowdapp@redhat.com>
Reviewed-on: http://review.gluster.org/10966
Tested-by: Gluster Build System <jenkins@build.gluster.com>

1 files changed, 35 insertions, 6 deletions

diff --git a/xlators/cluster/dht/src/dht-helper.c b/xlators/cluster/dht/src/dht-helper.c
index 2f85066569d..85f242c0e56 100644
--- a/xlators/cluster/dht/src/dht-helper.c
+++ b/xlators/cluster/dht/src/dht-helper.c
@@ -820,11 +820,23 @@ dht_init_subvolumes (xlator_t *this, dht_conf_t *conf)
 static int
 dht_migration_complete_check_done (int op_ret, call_frame_t *frame, void *data)
 {
-        dht_local_t *local = NULL;
+        dht_local_t *local  = NULL;
+        xlator_t    *subvol = NULL;
 
         local = frame->local;
 
-        local->rebalance.target_op_fn (THIS, frame, op_ret);
+        if (op_ret == -1)
+                goto out;
+
+        if (local->cached_subvol == NULL) {
+                local->op_errno = EINVAL;
+                goto out;
+        }
+
+        subvol = local->cached_subvol;
+
+out:
+        local->rebalance.target_op_fn (THIS, subvol, frame);
 
         return 0;
 }
@@ -1003,13 +1015,30 @@ dht_rebalance_complete_check (xlator_t *this, call_frame_t *frame)
 
 /* During 'in-progress' state, both nodes should have the file */
 static int
-dht_inprogress_check_done (int op_ret, call_frame_t *sync_frame, void *data)
+dht_inprogress_check_done (int op_ret, call_frame_t *frame, void *data)
 {
-        dht_local_t *local = NULL;
+        dht_local_t *local  = NULL;
+        xlator_t    *subvol = NULL;
+        inode_t     *inode  = NULL;
 
-        local = sync_frame->local;
+        local = frame->local;
+
+        if (op_ret == -1)
+                goto out;
+
+        inode = local->loc.inode ? local->loc.inode : local->fd->inode;
+
+        dht_inode_ctx_get1 (THIS, inode, &subvol);
+        if (!subvol) {
+                subvol = dht_subvol_get_cached (THIS, inode);
+                if (!subvol) {
+                        local->op_errno = EINVAL;
+                        goto out;
+                }
+        }
 
-        local->rebalance.target_op_fn (THIS, sync_frame, op_ret);
+out:
+        local->rebalance.target_op_fn (THIS, subvol, frame);
 
         return 0;
 }