[PATCH] splice: partial write fix

Currently if partial write has happened while ->commit_write() then page
wasn't marked as accessed and rebalanced.
Signed-off-by: NMonakhov Dmitriy <dmonakhov@openvz.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

fs/splice.c

@@ -627,18 +627,25 @@ static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 	}
 
 	ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len);
-	if (!ret) {
+	if (ret) {
+		if (ret == AOP_TRUNCATED_PAGE) {
+			page_cache_release(page);
+			goto find_page;
+		}
+		if (ret < 0)
+			goto out;
 		/*
-		 * Return the number of bytes written and mark page as
-		 * accessed, we are now done!
+		 * Partial write has happened, so 'ret' already initialized by
+		 * number of bytes written, Where is nothing we have to do here.
 		 */
+	} else
 		ret = this_len;
-		mark_page_accessed(page);
-		balance_dirty_pages_ratelimited(mapping);
-	} else if (ret == AOP_TRUNCATED_PAGE) {
-		page_cache_release(page);
-		goto find_page;
-	}
+	/*
+	 * Return the number of bytes written and mark page as
+	 * accessed, we are now done!
+	 */
+	mark_page_accessed(page);
+	balance_dirty_pages_ratelimited(mapping);
 out:
 	page_cache_release(page);
 	unlock_page(page);