QUOTACTL(2)							System Calls Manual						       QUOTACTL(2)

NAME

       quotactl - manipulate disk quotas

SYNOPSIS

       #include <linux/quota.h>
       #include <linux/xqm.h>

       long quotactl(int cmd, char *special, qid_t id, caddr_t addr)

DESCRIPTION

       The  quotactl() call manipulates disk quotas.  cmd indicates a command to be applied to UID id or GID id.  To set the type of quota use the
       QCMD(cmd, type) macro.  special is a pointer to a null-terminated string containing the path name of  the  block  special  device  for  the
       filesystem  being  manipulated.	addr is the address of an optional, command specific, data structure which is copied in or out of the sys-
       tem.  The interpretation of addr is given with each command below.

       Q_QUOTAON      Turn on quotas for a filesystem.	addr points to the path name of file containing the quotas for the filesystem.	The  quota
		      file must exist; it is normally created with the quotacheck(8) program.  This call is restricted to the super-user.

       Q_QUOTAOFF     Turn off quotas for a filesystem.  addr and id are ignored.  This call is restricted to the super-user.

       Q_GETQUOTA     Get  disk  quota	limits	and  current  usage  for user or group id.  addr is a pointer to a mem_dqblk structure (defined in
		      <linux/quota.h>).  Only the super-user may get the quotas of a user other than himself.

       Q_SETQUOTA     Set disk quota limits and current usage for user or group id.  addr is a	pointer  to  a	mem_dqblk  structure  (defined	in
		      <linux/quota.h>).  This call is restricted to the super-user.

       Q_SETQLIM      Set  disk quota limits for user or group id.  addr is a pointer to a mem_dqblk structure (defined in <linux/quota.h>).  This
		      call is restricted to the super-user.

       Q_SETUSE       Set current usage for user or group id.  addr is a pointer to a mem_dqblk structure (defined in <linux/quota.h>).  This call
		      is restricted to the super-user.

       Q_SYNC	      Update  the  on-disk  copy of quota usages for a filesystem.  If special is null then all filesystems with active quotas are
		      sync'ed.	addr and id are ignored.

       Q_GETSTATS     Get statistics and other generic information about quota subsystem.  addr should be a pointer to dqstats structure  (defined
		      in <linux/quota.h>) in which data should be stored.  special and id are ignored.

       New quota format also allows following additional calls:

       Q_GETINFO      Get  information	(like  grace  times)  about  quotafile.   addr	should	be  a  pointer to mem_dqinfo structure (defined in
		      <linux/quota.h>).  id is ignored.

       Q_SETINFO      Set information about quotafile.	addr should be a pointer to mem_dqinfo structure  (defined  in	<linux/quota.h>).   id	is
		      ignored. This operation is restricted to super-user.

       Q_SETGRACE     Set  grace  times  in  information  about  quotafile.   addr  should  be	a  pointer  to	mem_dqinfo  structure  (defined in
		      <linux/quota.h>).  id is ignored. This operation is restricted to super-user.

       Q_SETFLAGS     Set flags in information about quotafile. These flags are defined in <linux/quota.h>.  Note  that  there	are  currently	no
		      defined  flags.	addr should be a pointer to mem_dqinfo structure (defined in <linux/quota.h>).	id is ignored. This opera-
		      tion is restricted to super-user.

       For XFS filesystems making use of the XFS Quota Manager (XQM), the above commands are bypassed and the following commands are used:

       Q_XQUOTAON     Turn on quotas for an XFS filesystem.  XFS provides the ability to turn on/off quota limit enforcement with  quota  account-
		      ing.   Therefore,  XFS expects the addr to be a pointer to an unsigned int that contains either the flags XFS_QUOTA_UDQ_ACCT
		      and/or XFS_QUOTA_UDQ_ENFD (for user quota), or XFS_QUOTA_GDQ_ACCT and/or XFS_QUOTA_GDQ_ENFD (for group quota), as defined in
		      <linux/xqm.h>.  This call is restricted to the superuser.

       Q_XQUOTAOFF    Turn  off quotas for an XFS filesystem.  As in Q_QUOTAON, XFS filesystems expect a pointer to an unsigned int that specifies
		      whether quota accounting and/or limit enforcement need to be turned off.	This call is restricted to the superuser.

       Q_XGETQUOTA    Get disk quota limits and current usage for  user  id.   addr  is  a  pointer  to  a  fs_disk_quota  structure  (defined	in
		      <linux/xqm.h>).  Only the superuser may get the quotas of a user other than himself.

       Q_XSETQLIM     Set disk quota limits for user id.  addr is a pointer to a fs_disk_quota structure (defined in <linux/xqm.h>).  This call is
		      restricted to the superuser.

       Q_XGETQSTAT    Returns a fs_quota_stat structure containing XFS filesystem specific quota information.  This is useful in finding  out  how
		      much space is spent to store quota information, and also to get quotaon/off status of a given local XFS filesystem.

       Q_XQUOTARM     Free the disk space taken by disk quotas.  Quotas must have already been turned off.

       There  is no command equivalent to Q_SYNC for XFS since sync(1) writes quota information to disk (in addition to the other filesystem meta-
       data it writes out).

RETURN VALUES

       quotactl() returns:

       0      on success.

       -1     on failure and sets errno to indicate the error.

ERRORS

       EFAULT	      addr or special are invalid.

       EINVAL	      The kernel has not been compiled with the QUOTA option.

		      cmd is invalid.

       ENOENT	      The file specified by special or addr does not exist.

       ENOTBLK	      special is not a block device.

       EPERM	      The call is privileged and the caller was not the super-user.

       ESRCH	      No disc quota is found for the indicated user.

		      Quotas have not been turned on for this filesystem.

       EUSERS	      The quota table is full.

       If cmd is Q_QUOTAON, quotactl() may set errno to:

       EACCES	      The quota file pointed to by addr exists but is not a regular file.

		      The quota file pointed to by addr exists but is not on the filesystem pointed to by special.

       EBUSY	      Q_QUOTAON attempted while another Q_QUOTAON has already taken place.

SEE ALSO

       quota(1), getrlimit(2), quotacheck(8), quotaon(8)

																       QUOTACTL(2)