On Wed, Apr 1, 2020 at 11:05 AM Karel Zak wrote: > > On Tue, Mar 31, 2020 at 10:52:52PM +0100, David Howells wrote: > > Christian Brauner wrote: > > > > > querying all properties of a mount atomically all-at-once, > > > > I don't actually offer that, per se. > > > > Having an atomic all-at-once query for a single mount is actually quite a > > burden on the system. There's potentially a lot of state involved, much of > > which you don't necessarily need. > > If all means "all possible attributes" than it is unnecessary, for > example ext4 timestamps or volume uuid/label are rarely necessary. > We usually need together (as consistent set): > > source > mountpoint > FS type > FS root (FSINFO_ATTR_MOUNT_PATH) > FS options (FSINFO_ATTR_CONFIGURATION) > VFS attributes > VFS propagation flags > mount ID > parent ID > devno (or maj:min) This is trivial with mountfs (reuse format of /proc/PID/mountinfo): # cat /mnt/30/info 30 20 0:14 / /mnt rw,relatime - mountfs none rw Attached patch applies against readfile patch. We might want something more generic, and it won't get any simpler: mount.h | 1 + mountfs/super.c | 12 +++++++++++- proc_namespace.c | 2 +- 3 files changed, 13 insertions(+), 2 deletions(-) Thanks, Miklos