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NAME | DESCRIPTION | SEE ALSO | COLOPHON |
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proc_pid_mountinfo(5) File Formats Manual proc_pid_mountinfo(5)
/proc/pid/mountinfo - mount information
/proc/pid/mountinfo (since Linux 2.6.26)
This file contains information about mounts in the
process's mount namespace (see mount_namespaces(7)). It
supplies various information (e.g., propagation state, root
of mount for bind mounts, identifier for each mount and its
parent) that is missing from the (older) /proc/pid/mounts
file, and fixes various other problems with that file
(e.g., nonextensibility, failure to distinguish per-mount
versus per-superblock options).
The 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)
The numbers in parentheses are labels for the descriptions
below:
(1) mount ID: a unique ID for the mount (may be reused
after umount(2)).
(2) parent ID: the ID of the parent mount (or of self for
the root of this mount namespace's mount tree).
If a new mount is stacked on top of a previous
existing mount (so that it hides the existing mount)
at pathname P, then the parent of the new mount is the
previous mount at that location. Thus, when looking
at all the mounts stacked at a particular location,
the top-most mount is the one that is not the parent
of any other mount at the same location. (Note,
however, that this top-most mount will be accessible
only if the longest path subprefix of P that is a
mount point is not itself hidden by a stacked mount.)
If the parent mount lies outside the process's root
directory (see chroot(2)), the ID shown here won't
have a corresponding record in mountinfo whose mount
ID (field 1) matches this parent mount ID (because
mounts that lie outside the process's root directory
are not shown in mountinfo). As a special case of
this point, the process's root mount may have a parent
mount (for the initramfs filesystem) that lies outside
the process's root directory, and an entry for that
mount will not appear in mountinfo.
(3) major:minor: the value of st_dev for files on this
filesystem (see stat(2)).
(4) root: the pathname of the directory in the filesystem
which forms the root of this mount.
(5) mount point: the pathname of the mount point relative
to the process's root directory.
(6) mount options: per-mount options (see mount(2)).
(7) optional fields: zero or more fields of the form
"tag[:value]"; see below.
(8) separator: the end of the optional fields is marked by
a single hyphen.
(9) filesystem type: the filesystem type in the form
"type[.subtype]".
(10) mount source: filesystem-specific information or
"none".
(11) super options: per-superblock options (see mount(2)).
Currently, the possible optional fields are shared, master,
propagate_from, and unbindable. See mount_namespaces(7)
for a description of these fields. Parsers should ignore
all unrecognized optional fields.
For more information on mount propagation see
Documentation/filesystems/sharedsubtree.rst (or
Documentation/filesystems/sharedsubtree.txt before Linux
5.8) in the Linux kernel source tree.
proc(5)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.10.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2025-02-02. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.10 2024-05-02 proc_pid_mountinfo(5)
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HTML rendering created 2025-02-02 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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