# proc_pid_mountinfo

## NAME



           /proc/pid/mountinfo - mount information
    


## DESCRIPTION



           _/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.
    


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