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quotactl

NAME

quotactl - manipulate disk quota

SYNOPSIS

 #include <sys/types.h>
 
 #include <sys/quota.h>
 
 int quotactl(int cmd, const char *special, int id, caddr_t addr);
 

DESCRIPTION

The quota system defines for each user and/or group a soft limit and a hard limit bounding the amount of disk space that can be used on a given file system. The hard limit cannot be crossed. The soft limit can be crossed, but warnings will ensue. Moreover, the user cannot be above the soft limit for more than one week (by default) at a time: after this week the soft limit counts as hard limit.

The quotactl() system call manipulates these quota. Its first argument is of the form QCMD(subcmd,type) where type is either USRQUOTA or GRPQUOTA (for user quota and group quota, respectively), and subcmd is described below.

The second argument special is the block special device these quota apply to. It must be mounted.

The third argument id is the user or group ID these quota apply to (when relevant).

The fourth argument addr is the address of a data structure, depending on the command.

The subcmd is one of

Q_QUOTAON

Enable quota. The addr argument is the pathname of the file containing the quota for the file system.

Q_QUOTAOFF

Disable quota.

Q_GETQUOTA

Get limits and current usage of disk space. The addr argument is a pointer to a dqblk structure (defined in <sys/quota.h>).

Q_SETQUOTA

Set limits and current usage; addr is as before.

Q_SETQLIM

Set limits; addr is as before.

Q_SETUSE

Set usage.

Q_SYNC

Sync disk copy of a file system's quota.

Q_GETSTATS

Get collected stats.

RETURN VALUE

On success, quotactl() returns 0. On error, -1 is returned, and errno is set appropriately.

ERRORS

EACCES

The quota file is not an ordinary file.

EBUSY

Q_QUOTAON was asked, but quotas were enabled already.

EFAULT

Bad addr value.

EINVAL

type is not a known quota type. Or, special could not be found.

EIO

Cannot read or write the quota file.

EMFILE

Too many open files: cannot open quota file.

ENODEV

special cannot be found in the mount table.

ENOPKG

The kernel was compiled without quota support.

ENOTBLK

special is not a block special device.

EPERM

The process was not root (for the file system), and Q_GETQUOTA was asked for another id than that of the process itself, or anything other than Q_GETSTATS or Q_SYNC was asked.

ESRCH

Q_GETQUOTA or Q_SETQUOTA or Q_SETUSE or Q_SETQLIM was asked for a file system that didn't have quota enabled.

CONFORMING TO

BSD.

SEE ALSO

quota(1), getrlimit(2), setrlimit(2), ulimit(3), quotacheck(8), quotaon(8)

COLOPHON

This page is part of release 3.15 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.