2 files changed, 28 insertions, 1 deletions

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 30c9626f96b0..4ec67f8d70aa 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -168,6 +168,23 @@ nfs_page_group_lock(struct nfs_page *req, bool nonblock)
 }
 
 /*
+ * nfs_page_group_lock_wait - wait for the lock to clear, but don't grab it
+ * @req - a request in the group
+ *
+ * This is a blocking call to wait for the group lock to be cleared.
+ */
+void
+nfs_page_group_lock_wait(struct nfs_page *req)
+{
+        struct nfs_page *head = req->wb_head;
+
+        WARN_ON_ONCE(head != head->wb_head);
+
+        wait_on_bit(&head->wb_flags, PG_HEADLOCK,
+                TASK_UNINTERRUPTIBLE);
+}
+
+/*
  * nfs_page_group_unlock - unlock the head of the page group
  * @req - request in group that is to be unlocked
  */
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index e056f617adf2..175d5d073ccf 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -478,13 +478,23 @@ try_again:
                 return NULL;
         }
 
-        /* lock each request in the page group */
+        /* holding inode lock, so always make a non-blocking call to try the
+         * page group lock */
         ret = nfs_page_group_lock(head, true);
         if (ret < 0) {
                 spin_unlock(&inode->i_lock);
+
+                if (!nonblock && ret == -EAGAIN) {
+                        nfs_page_group_lock_wait(head);
+                        nfs_release_request(head);
+                        goto try_again;
+                }
+
                 nfs_release_request(head);
                 return ERR_PTR(ret);
         }
+
+        /* lock each request in the page group */
         subreq = head;
         do {
                 /*