@@ -29,6 +29,8 @@ static int flags_by_mnt(int mnt_flags)
flags |= ST_NODIRATIME;
if (mnt_flags & MNT_RELATIME)
flags |= ST_RELATIME;
+ if (mnt_flags & MNT_UNBINDABLE)
+ flags |= ST_UNBINDABLE;
return flags;
}
@@ -40,5 +40,6 @@ struct kstatfs {
#define ST_NOATIME (1<<10) /* do not update access times */
#define ST_NODIRATIME (1<<11) /* do not update directory access times */
#define ST_RELATIME (1<<12) /* update atime relative to mtime/ctime */
+#define ST_UNBINDABLE (1<<17) /* change to unbindable */
#endif
Currently userspace can only determine whether a mountpoint is unbindable by parsing /proc/<pid>/mountinfo. It would be convenient to simply retrieve this property with a statvfs() call. This let's userspace avoid costly parsing, supports cases where /proc is not mounted, and supports usecases where file descriptors to mountpoints are passed between processes that are inspected via fstatvfs(). Signed-off-by: Christian Brauner <christian@brauner.io> --- v0->v1: * non-functional changes: extend commit message --- fs/statfs.c | 2 ++ include/linux/statfs.h | 1 + 2 files changed, 3 insertions(+)