[PATCH 5/8] btrfs-progs: utils: Fallback to open without O_NOATIME flag in find_mount_root():

[Misono Tomohiro]

O_NOATIME flag requires effective UID of process matches file's owner
or has CAP_FOWNER capabilities. Fallback to open without O_NOATIME flag
so that non-privileged user can also call find_mount_root().

This is a preparation work to allow non-privileged user to call
"subvolume show".

Signed-off-by: Misono Tomohiro <misono.tomoh...@jp.fujitsu.com>
Signed-off-by: David Sterba <dste...@suse.com>
---
 utils.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/utils.c b/utils.c
index 3a4bc92a..8ce8417d 100644
--- a/utils.c
+++ b/utils.c
@@ -2054,6 +2054,9 @@ int find_mount_root(const char *path, char **mount_root)
        char *longest_match = NULL;
 
        fd = open(path, O_RDONLY | O_NOATIME);
+       if (fd < 0 && errno == EPERM)
+               fd = open(path, O_RDONLY);
+
        if (fd < 0)
                return -errno;
        close(fd);
-- 
2.19.1