From 06a0277c2aab1442c724217957fd5f915ace2753 Mon Sep 17 00:00:00 2001
From: Zhuling <zhuling8@huawei.com>
Date: Thu, 22 Jul 2021 10:15:15 +0800
Subject: [PATCH 42/72] reg-file: fix dump fail problem with null seek op

Some customizing `struct file_operations` implementation has
no `llseek`, therefore ignore the no-implementation errno.

Fix file dumping fail problem when the file seek op is null.

Signed-off-by: Jingxian He <hejingxian@huawei.com>
Signed-off-by: fu.lin <fulin10@huawei.com>
---
 criu/files-reg.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/criu/files-reg.c b/criu/files-reg.c
index 1a3b836..6dc8745 100644
--- a/criu/files-reg.c
+++ b/criu/files-reg.c
@@ -2176,9 +2176,18 @@ static int do_open_reg(int ns_root_fd, struct reg_file_info *rfi, void *arg)
 	 */
 	if (!(rfi->rfe->flags & O_PATH)) {
 		if (rfi->rfe->pos != -1ULL && lseek(fd, rfi->rfe->pos, SEEK_SET) < 0) {
-			pr_perror("Can't restore file pos");
-			close(fd);
-			return -1;
+			/*
+			 * Some customizing `struct file_operations`
+			 * implementation has no `llseek`, therefore
+			 * ignore the no-implementation errno.
+			 */
+			if (errno == ESPIPE) {
+				pr_warn("No ability to restore file ops\n");
+			} else {
+				pr_perror("Can't restore file pos");
+				close(fd);
+				return -1;
+			}
 		}
 	}
 
-- 
2.34.1