[RFC,4/7] btrfs-progs: fallback to open without O_NOATIME flag in, find_mount_root()

Commit Message

Misono Tomohiro March 6, 2018, 8:35 a.m. UTC

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 normal user can also call find_mount_root().

This is a preparation work to allow normal user to call "subvolume show".

Signed-off-by: Tomohiro Misono <[e-mail]>
---
 utils.c | 3 +++
 1 file changed, 3 insertions(+)

Patch

diff --git a/utils.c b/utils.c
index 81c54faa..acea70a5 100644
--- a/utils.c
+++ b/utils.c
@@ -2045,6 +2045,9 @@  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);