/proc/<pid>/mountinfo provides information about mounts.
This file contains lines of the form:
36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 - ext3 /dev/root rw,errors=continue
(1)(2)(3) (4) (5) (6) (7) (8) (9) (10) (11)
where:
(1) mount ID: unique identifier of the mount (may be reused after umount)
(2) parent ID: ID of parent (or of self for the top of the mount tree)
(3) major:minor: value of st_dev for files on filesystem
(4) root: root of the mount within the filesystem
(5) mount point: mount point relative to the process's root
(6) mount options: per mount options
(7) optional fields: zero or more fields of the form “tag[:value]”
(8) separator: marks the end of the optional fields
(9) filesystem type: name of filesystem of the form “type[.subtype]”
(10) mount source: filesystem specific information or “none”
(11) super options: per super block options
Parsers should ignore all unrecognised optional fields. Currently the possible optional fields are:
shared:X mount is shared in peer group X
master:X mount is slave to peer group X
propagate_from:X mount is slave and receives propagation from peer group X (*)
unbindable mount is unbindable
where:
(*) X is the closest dominant peer group under the process's root. If X is the immediate master of the mount, or if there's no dominant peer group under the same root, then only the “master:X” field is present and not the “propagate_from:X” field.