nfs: handle multiple reqs in nfs_wb_page_cancel

Use nfs_lock_and_join_requests to merge all subrequests into the head request -
this cancels and dereferences all subrequests.

Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 21 insertions, 20 deletions

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 9f4424c464a0..bdc4db23951e 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -1799,27 +1799,28 @@ int nfs_wb_page_cancel(struct inode *inode, struct page *page)
         struct nfs_page *req;
         int ret = 0;
 
-        for (;;) {
-                wait_on_page_writeback(page);
-                req = nfs_page_find_head_request(page);
-                if (req == NULL)
-                        break;
-                if (nfs_lock_request(req)) {
-                        nfs_clear_request_commit(req);
-                        nfs_inode_remove_request(req);
-                        /*
-                         * In case nfs_inode_remove_request has marked the
-                         * page as being dirty
-                         */
-                        cancel_dirty_page(page, PAGE_CACHE_SIZE);
-                        nfs_unlock_and_release_request(req);
-                        break;
-                }
-                ret = nfs_wait_on_request(req);
-                nfs_release_request(req);
-                if (ret < 0)
-                        break;
+        wait_on_page_writeback(page);
+
+        /* blocking call to cancel all requests and join to a single (head)
+         * request */
+        req = nfs_lock_and_join_requests(page, false);
+
+        if (IS_ERR(req)) {
+                ret = PTR_ERR(req);
+        } else if (req) {
+                /* all requests from this page have been cancelled by
+                 * nfs_lock_and_join_requests, so just remove the head
+                 * request from the inode / page_private pointer and
+                 * release it */
+                nfs_inode_remove_request(req);
+                /*
+                 * In case nfs_inode_remove_request has marked the
+                 * page as being dirty
+                 */
+                cancel_dirty_page(page, PAGE_CACHE_SIZE);
+                nfs_unlock_and_release_request(req);
         }
+
         return ret;
 }