quotactl

quotactl – Set disk quotas

#include <sys/quota.h>
       #include <sys/types.h>
       #include <xfs/xqm.h>
       #include <linux/dqblk_v1.h>
       #include <linux/dqblk_v2.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, com-
       mand specific, data structure which is copied in or out of the  system.
       The interpretation of addr is given with each command below.

       Q_QUOTAON      Turn  on quotas for a filesystem.  id is the identifica-
                      tion number of the quota format to be used. Format  num-
                      bers  are defined in the header file of appropriate for-
                      mat. Currently there are  two  supported  quota  formats
                      whose  numbers  are  defined  by  constants QFMT_VFS_OLD
                      (original quota format)  and  QFMT_VFS_V0  (new  VFS  v0
                      quota  format).   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 quo-
                      tacheck(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 an dqblk structure
                      (defined in <sys/quota.h>).  The field dqb_valid defines
                      the entries in the structure which are set correctly. On
                      Q_GETQUOTA call all entries are valid. Only  the  super-
                      user may get the quotas of a user other than himself.

       Q_SETQUOTA     Set  current  quota  information  for  user or group id.
                      addr is a pointer to  an  dqblk  structure  (defined  in
                      <sys/quota.h>).    The  field  dqb_valid  defines  which
                      entries in the quota structure are valid and  should  be
                      set.  The  constants  for dqb_valid field are defined in
                      the <sys/quota.h> header file. This call obsoletes calls
                      Q_SETQLIM and Q_SETUSE in the previous quota interfaces.
                      This call is restricted to the super-user.

       Q_GETINFO      Get information  (like  grace  times)  about  quotafile.
                      addr should be a pointer to an dqinfo structure (defined
                      in <sys/quota.h>).  The dqi_valid field in the structure
                      should be a pointer to a memory (4 bytes) where the for-
                      mat number will be stored.

       Q_SYNC         Update the on-disk copy of quota usages for  a  filesys-
                      tem.   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 struc-
                      ture (defined in <sys/quota.h>) in which data should  be
                      stored.  special and id are ignored.

       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 accounting.  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
                      <xfs/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 enforce-
                      ment 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  <xfs/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  <xfs/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 metadata
       it writes out).

                      cmd or type 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.

       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.

       EINVAL         The quota file is corrupted.

       ESRCH          Specified quota format was not found.

       EBUSY          Q_QUOTAON  attempted while another Q_QUOTAON has already
                      taken place.