From 264b4a8d24ea86396ca508cbce24855ff704638e Mon Sep 17 00:00:00 2001
From: Liu Hua <weldonliu@tencent.com>
Date: Tue, 13 Apr 2021 13:09:17 +0800
Subject: [PATCH] tiny fix on function dump_empty_fs

return value of is_empty_dir:
*  < 0 : open directory stream failed
*    0 : directory is not empty
*    1 : directory is empty

Signed-off-by: Liu Hua <weldonliu@tencent.com>
---
 criu/filesystems.c | 4 ++--
 criu/util.c        | 7 +++++++
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/criu/filesystems.c b/criu/filesystems.c
index fc53f4e5d..94d348a8e 100644
--- a/criu/filesystems.c
+++ b/criu/filesystems.c
@@ -656,12 +656,12 @@ static int dump_empty_fs(struct mount_info *pm)
 		return fd;
 
 	ret = is_empty_dir(fd);
-	if (ret < 0) {
+	if (ret == 0) {
 		pr_err("%s isn't empty\n", pm->fstype->name);
 		return -1;
 	}
 
-	return ret ? 0 : -1;
+	return ret == 1 ? 0 : -1;
 }
 
 /*
diff --git a/criu/util.c b/criu/util.c
index 76624dc5a..ca09f02a1 100644
--- a/criu/util.c
+++ b/criu/util.c
@@ -731,7 +731,13 @@ int is_root_user(void)
 /*
  * is_empty_dir will always close the FD dirfd: either implicitly
  * via closedir or explicitly in case fdopendir had failed
+ *
+ * return values:
+ *   < 0 : open directory stream failed
+ *     0 : directory is not empty
+ *     1 : directory is empty
  */
+
 int is_empty_dir(int dirfd)
 {
 	int ret = 0;
@@ -740,6 +746,7 @@ int is_empty_dir(int dirfd)
 
 	fdir = fdopendir(dirfd);
 	if (!fdir) {
+		pr_perror("open directory stream by fd %d failed", dirfd);
 		close_safe(&dirfd);
 		return -1;
 	}