CIFS: Fix leaking locked VFS cache pages in writeback retry

[ Upstream commit 165df9a0 ]

If we don't find a writable file handle when retrying writepages
we break of the loop and do not unlock and put pages neither from
wdata2 nor from the original wdata. Fix this by walking through
all the remaining pages and cleanup them properly.

Cc: <stable@vger.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

fs/cifs/cifssmb.c

@@ -2033,12 +2033,13 @@ cifs_writev_requeue(struct cifs_writedata *wdata)
 
 		wdata2->cfile = find_writable_file(CIFS_I(inode), false);
 		if (!wdata2->cfile) {
-			cifs_dbg(VFS, "No writable handles for inode\n");
+			cifs_dbg(VFS, "No writable handle to retry writepages\n");
 			rc = -EBADF;
-			break;
+		} else {
+			wdata2->pid = wdata2->cfile->pid;
+			rc = server->ops->async_writev(wdata2,
+						       cifs_writedata_release);
 		}
-		wdata2->pid = wdata2->cfile->pid;
-		rc = server->ops->async_writev(wdata2, cifs_writedata_release);
 
 		for (j = 0; j < nr_pages; j++) {
 			unlock_page(wdata2->pages[j]);
@@ -2053,6 +2054,7 @@ cifs_writev_requeue(struct cifs_writedata *wdata)
 			kref_put(&wdata2->refcount, cifs_writedata_release);
 			if (is_retryable_error(rc))
 				continue;
+			i += nr_pages;
 			break;
 		}
 
@@ -2060,6 +2062,13 @@ cifs_writev_requeue(struct cifs_writedata *wdata)
 		i += nr_pages;
 	} while (i < wdata->nr_pages);
 
+	/* cleanup remaining pages from the original wdata */
+	for (; i < wdata->nr_pages; i++) {
+		SetPageError(wdata->pages[i]);
+		end_page_writeback(wdata->pages[i]);
+		put_page(wdata->pages[i]);
+	}
+
 	if (rc != 0 && !is_retryable_error(rc))
 		mapping_set_error(inode->i_mapping, rc);
 	kref_put(&wdata->refcount, cifs_writedata_release);