mount: add debug logging for the case when we knowingly ignore an error

diff --git a/src/mount/mount-tool.c b/src/mount/mount-tool.c
index 21c3b1302d10ddd4027909ffe47b0fafb32de33a..23083fd16ea3aea5eab5dd4982ba4c7c22647a34 100644 (file)
--- a/src/mount/mount-tool.c
+++ b/src/mount/mount-tool.c
@@ -779,8 +779,10 @@ static int find_loop_device(const char *backing_file, char **loop_dev) {
                         return -ENOMEM;
 
                 r = read_one_line_file(sys, &fname);
-                if (r < 0)
+                if (r < 0) {
+                        log_debug_errno(r, "Failed to read %s, ignoring: %m", sys);
                         continue;
+                }
 
                 if (files_same(fname, backing_file, 0) <= 0)
                         continue;