cluster/afr: Don't do transactional flush if pre-op has been nowhere done.

If a pre-op has not been done on any subvolume at all, there
is no reason to make flush a transaction call.

Signed-off-by: Vikas Gorur <vikas@gluster.com>
Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 427 (flush on a file opened read-only should not hold locks)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=427

1 files changed, 106 insertions, 18 deletions

diff --git a/xlators/cluster/afr/src/afr.c b/xlators/cluster/afr/src/afr.c
index 33cd70cd478..f81b8005da0 100644
--- a/xlators/cluster/afr/src/afr.c
+++ b/xlators/cluster/afr/src/afr.c
@@ -1250,6 +1250,73 @@ afr_flush_done (call_frame_t *frame, xlator_t *this)
 
 
 int
+afr_plain_flush_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
+                     int32_t op_ret, int32_t op_errno)
+
+{
+	afr_local_t *local = NULL;
+
+	int call_count = -1;
+
+	local = frame->local;
+
+	LOCK (&frame->lock);
+	{
+		if (op_ret == 0)
+			local->op_ret = 0;
+
+		local->op_errno = op_errno;
+	}
+	UNLOCK (&frame->lock);
+
+	call_count = afr_frame_return (frame);
+
+	if (call_count == 0)
+		AFR_STACK_UNWIND (flush, frame, local->op_ret, local->op_errno);
+
+	return 0;
+}
+
+
+static int
+__no_pre_op_done (xlator_t *this, fd_t *fd)
+{
+        int i      = 0;
+        int op_ret = 1;
+
+        int _ret = 0;
+        uint64_t       ctx;
+        afr_fd_ctx_t * fd_ctx = NULL;
+
+        afr_private_t *priv = NULL;
+
+        priv = this->private;
+
+        LOCK (&fd->lock);
+        {
+                _ret = __fd_ctx_get (fd, this, &ctx);
+
+                if (_ret < 0) {
+                        goto out;
+                }
+
+                fd_ctx = (afr_fd_ctx_t *)(long) ctx;
+
+                for (i = 0; i < priv->child_count; i++) {
+                        if (fd_ctx->pre_op_done[i]) {
+                                op_ret = 0;
+                                break;
+                        }
+                }
+        }
+out:
+        UNLOCK (&fd->lock);
+
+        return op_ret;
+}
+
+
+int
 afr_flush (call_frame_t *frame, xlator_t *this, fd_t *fd)
 {
 	afr_private_t * priv  = NULL;
@@ -1262,20 +1329,15 @@ afr_flush (call_frame_t *frame, xlator_t *this, fd_t *fd)
 	int op_ret   = -1;
 	int op_errno = 0;
 
+        int i          = 0;
+        int call_count = 0;
+
 	VALIDATE_OR_GOTO (frame, out);
 	VALIDATE_OR_GOTO (this, out);
 	VALIDATE_OR_GOTO (this->private, out);
 
 	priv = this->private;
 
-        transaction_frame = copy_frame (frame);
-        if (!transaction_frame) {
-                op_errno = ENOMEM;
-                gf_log (this->name, GF_LOG_ERROR,
-			"Out of memory.");
-		goto out;
-        }
-
 	ALLOC_OR_GOTO (local, afr_local_t, out);
 
 	ret = AFR_LOCAL_INIT (local, priv);
@@ -1284,21 +1346,47 @@ afr_flush (call_frame_t *frame, xlator_t *this, fd_t *fd)
 		goto out;
 	}
 
-	transaction_frame->local = local;
+        call_count = afr_up_children_count (priv->child_count, local->child_up);
+
+        if (__no_pre_op_done (this, fd)) {
+                frame->local = local;
 
-        local->op = GF_FOP_FLUSH;
+                for (i = 0; i < priv->child_count; i++) {
+                        if (local->child_up[i]) {
+                                STACK_WIND_COOKIE (frame, afr_plain_flush_cbk,
+                                                   (void *) (long) i,
+                                                   priv->children[i],
+                                                   priv->children[i]->fops->flush,
+                                                   fd);
+                                if (!--call_count)
+                                        break;
+                        }
+                }
+        } else {
+                transaction_frame = copy_frame (frame);
+                if (!transaction_frame) {
+                        op_errno = ENOMEM;
+                        gf_log (this->name, GF_LOG_ERROR,
+                                "Out of memory.");
+                        goto out;
+                }
+
+                transaction_frame->local = local;
+
+                local->op = GF_FOP_FLUSH;
         
-        local->transaction.fop    = afr_flush_wind;
-        local->transaction.done   = afr_flush_done;
-        local->transaction.unwind = afr_flush_unwind;
+                local->transaction.fop    = afr_flush_wind;
+                local->transaction.done   = afr_flush_done;
+                local->transaction.unwind = afr_flush_unwind;
 
-        local->fd                 = fd_ref (fd);
+                local->fd                 = fd_ref (fd);
 
-        local->transaction.main_frame = frame;
-        local->transaction.start  = LLONG_MAX - 1;
-        local->transaction.len    = 0;
+                local->transaction.main_frame = frame;
+                local->transaction.start  = LLONG_MAX - 1;
+                local->transaction.len    = 0;
 
-        afr_transaction (transaction_frame, this, AFR_FLUSH_TRANSACTION);
+                afr_transaction (transaction_frame, this, AFR_FLUSH_TRANSACTION);
+        }
 
 	op_ret = 0;
 out: