1 files changed, 33 insertions, 9 deletions

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 9a18c5a69ace..47d892a1d363 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -472,20 +472,44 @@ out:
 	return result;
 }
 
-static void
-nfs_direct_join_group(struct list_head *list, struct inode *inode)
+static void nfs_direct_add_page_head(struct list_head *list,
+				     struct nfs_page *req)
+{
+	struct nfs_page *head = req->wb_head;
+
+	if (!list_empty(&head->wb_list) || !nfs_lock_request(head))
+		return;
+	if (!list_empty(&head->wb_list)) {
+		nfs_unlock_request(head);
+		return;
+	}
+	list_add(&head->wb_list, list);
+	kref_get(&head->wb_kref);
+	kref_get(&head->wb_kref);
+}
+
+static void nfs_direct_join_group(struct list_head *list, struct inode *inode)
 {
-	struct nfs_page *req, *next;
+	struct nfs_page *req, *subreq;
 
 	list_for_each_entry(req, list, wb_list) {
-		if (req->wb_head != req || req->wb_this_page == req)
+		if (req->wb_head != req) {
+			nfs_direct_add_page_head(&req->wb_list, req);
 			continue;
-		for (next = req->wb_this_page;
-				next != req->wb_head;
-				next = next->wb_this_page) {
-			nfs_list_remove_request(next);
-			nfs_release_request(next);
 		}
+		subreq = req->wb_this_page;
+		if (subreq == req)
+			continue;
+		do {
+			/*
+			 * Remove subrequests from this list before freeing
+			 * them in the call to nfs_join_page_group().
+			 */
+			if (!list_empty(&subreq->wb_list)) {
+				nfs_list_remove_request(subreq);
+				nfs_release_request(subreq);
+			}
+		} while ((subreq = subreq->wb_this_page) != req);
 		nfs_join_page_group(req, inode);
 	}
 }