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mount_attr(2type) mount_attr(2type)

NAME

mount_attr - what mount properties to set and clear

LIBRARY

Linux kernel headers

SYNOPSIS

#include <sys/mount.h>
struct mount_attr {
    u64 attr_set;     /* Mount properties to set */
    u64 attr_clr;     /* Mount properties to clear */
    u64 propagation;  /* Mount propagation type */
    u64 userns_fd;    /* User namespace file descriptor */

/* ... */ };

DESCRIPTION

Specifies which mount properties should be changed with mount_setattr(2).

The fields are as follows:

.attr_set
This field specifies which MOUNT_ATTR_* attribute flags to set.
.attr_clr
This field specifies which MOUNT_ATTR_* attribute flags to clear.
.propagation
This field specifies what mount propagation will be applied. The valid values of this field are the same propagation types described in mount_namespaces(7).
.userns_fd
This field specifies a file descriptor that indicates which user namespace to use as a reference for ID-mapped mounts with MOUNT_ATTR_IDMAP.

STANDARDS

Linux.

HISTORY

Linux 5.12. glibc 2.36.

Extra fields may be appended to the structure, with a zero value in a new field resulting in the kernel behaving as though that extension field was not present. Therefore, a user must zero-fill this structure on initialization.

SEE ALSO

mount_setattr(2)

2025-09-21 Linux man-pages (unreleased)