quotactl

QUOTACTL(2)                Linux Programmer's Manual               QUOTACTL(2)

NAME
       quotactl - manipulate disk quotas

SYNOPSIS
       #include <sys/quota.h>
       #include <xfs/xqm.h> /* for XFS quotas */

       int quotactl(int cmd, const char *special, int id, caddr_t addr);

DESCRIPTION
       The  quota  system  can  be  used  to set per-user, per-group, and per-
       project limits on the amount of disk space used on a  filesystem.   For
       each  user  and/or  group, a soft limit and a hard limit can be set for
       each filesystem.  The hard limit can't be exceeded.  The soft limit can
       be  exceeded, but warnings will ensue.  Moreover, the user can't exceed
       the soft limit for  more  than  grace  period  duration  (one  week  by
       default) at a time; after this, the soft limit counts as a hard limit.

       The  quotactl()  call  manipulates disk quotas.  The cmd argument indi-
       cates a command to be applied to the user or group ID specified in  id.
       To  initialize the cmd argument, use the QCMD(subcmd, type) macro.  The
       type value is either USRQUOTA, for user  quotas,  GRPQUOTA,  for  group
       quotas,  or (since Linux 4.1) PRJQUOTA, for project quotas.  The subcmd
       value is described below.

       The special argument is a pointer to a null-terminated string  contain-
       ing the pathname of the (mounted) block special device for the filesys-
       tem being manipulated.

       The addr argument is the address of an optional, command-specific, data
       structure  that  is copied in or out of the system.  The interpretation
       of addr is given with each command below.

       The subcmd value is one of the following:

       Q_QUOTAON
               Turn on quotas for a filesystem.  The id argument is the  iden-
               tification  number  of the quota format to be used.  Currently,
               there are three supported quota formats:

               QFMT_VFS_OLD The original quota format.

               QFMT_VFS_V0  The standard VFS v0 quota format, which can handle
                            32-bit  UIDs  and GIDs and quota limits up to 2^42
                            bytes and 2^32 inodes.

               QFMT_VFS_V1  A quota format that can  handle  32-bit  UIDs  and
                            GIDs  and  quota  limits  of  2^64  bytes and 2^64
                            inodes.

               The addr argument points to the pathname of a  file  containing
               the  quotas  for the filesystem.  The quota file must exist; it
               is normally created with the quotacheck(8) program.  This oper-
               ation requires privilege (CAP_SYS_ADMIN).

       Q_QUOTAOFF
               Turn  off  quotas  for a filesystem.  The addr and id arguments
               are    ignored.     This    operation    requires     privilege
               (CAP_SYS_ADMIN).

       Q_GETQUOTA
               Get  disk  quota limits and current usage for user or group id.
               The addr argument is a pointer to a dqblk structure defined  in
               <sys/quota.h> as follows:

                   /* uint64_t is an unsigned 64-bit integer;
                      uint32_t is an unsigned 32-bit integer */

                   struct dqblk {      /* Definition since Linux 2.4.22 */
                       uint64_t dqb_bhardlimit;  /* Absolute limit on disk
                                                    quota blocks alloc */
                       uint64_t dqb_bsoftlimit;  /* Preferred limit on
                                                    disk quota blocks */
                       uint64_t dqb_curspace;    /* Current occupied space
                                                    (in bytes) */
                       uint64_t dqb_ihardlimit;  /* Maximum number of
                                                    allocated inodes */
                       uint64_t dqb_isoftlimit;  /* Preferred inode limit */
                       uint64_t dqb_curinodes;   /* Current number of
                                                    allocated inodes */
                       uint64_t dqb_btime;       /* Time limit for excessive
                                                    disk use */
                       uint64_t dqb_itime;       /* Time limit for excessive
                                                    files */
                       uint32_t dqb_valid;       /* Bit mask of QIF_*
                                                    constants */
                   };

                   /* Flags in dqb_valid that indicate which fields in
                      dqblk structure are valid. */

                   #define QIF_BLIMITS   1
                   #define QIF_SPACE     2
                   #define QIF_ILIMITS   4
                   #define QIF_INODES    8
                   #define QIF_BTIME     16
                   #define QIF_ITIME     32
                   #define QIF_LIMITS    (QIF_BLIMITS | QIF_ILIMITS)
                   #define QIF_USAGE     (QIF_SPACE | QIF_INODES)
                   #define QIF_TIMES     (QIF_BTIME | QIF_ITIME)
                   #define QIF_ALL       (QIF_LIMITS | QIF_USAGE | QIF_TIMES)

               The  dqb_valid  field is a bit mask that is set to indicate the
               entries in the dqblk structure that are valid.  Currently,  the
               kernel  fills  in  all entries of the dqblk structure and marks
               them as valid in the dqb_valid field.  Unprivileged  users  may
               retrieve   only   their   own   quotas;   a   privileged   user
               (CAP_SYS_ADMIN) can retrieve the quotas of any user.

       Q_GETNEXTQUOTA (since Linux 4.6)
               This operation is the same as Q_GETQUOTA, but it returns  quota
               information  for  the  next ID greater than or equal to id that
               has a quota set.

               The addr argument is a pointer to a nextdqblk  structure  whose
               fields  are  as  for  the  dqblk,  except for the addition of a
               dqb_id field that is used to return  the  ID  for  which  quota
               information is being returned:

                   struct nextdqblk {
                       uint64_t dqb_bhardlimit;
                       uint64_t dqb_bsoftlimit;
                       uint64_t dqb_curspace;
                       uint64_t dqb_ihardlimit;
                       uint64_t dqb_isoftlimit;
                       uint64_t dqb_curinodes;
                       uint64_t dqb_btime;
                       uint64_t dqb_itime;
                       uint32_t dqb_valid;
                       uint32_t dqb_id;

                   };

       Q_SETQUOTA
               Set  quota information for user or group id, using the informa-
               tion supplied in the dqblk structure pointed to by  addr.   The
               dqb_valid  field of the dqblk structure indicates which entries
               in the structure have been set by the caller.   This  operation
               supersedes  the Q_SETQLIM and Q_SETUSE operations in the previ-
               ous  quota  interfaces.   This  operation  requires   privilege
               (CAP_SYS_ADMIN).

       Q_GETINFO (since Linux 2.4.22)
               Get  information  (like grace times) about quotafile.  The addr
               argument should be a  pointer  to  a  dqinfo  structure.   This
               structure is defined in <sys/quota.h> as follows:

                   /* uint64_t is an unsigned 64-bit integer;
                      uint32_t is an unsigned 32-bit integer */

                   struct dqinfo {         /* Defined since kernel 2.4.22 */
                       uint64_t dqi_bgrace;  /* Time before block soft limit
                                                becomes hard limit */
                       uint64_t dqi_igrace;  /* Time before inode soft limit
                                                becomes hard limit */
                       uint32_t dqi_flags;   /* Flags for quotafile
                                                (DQF_*) */
                       uint32_t dqi_valid;
                   };

                   /* Bits for dqi_flags */

                   /* Quota format QFMT_VFS_OLD */

                   #define DQF_ROOT_SQUASH (1 << 0) /* Root squash enabled */
                                 /* Before Linux v4.0, this had been defined
                                    privately as V1_DQF_RSQUASH */

                   /* Quota format QFMT_VFS_V0 / QFMT_VFS_V1 */

                   #define DQF_SYS_FILE    (1 << 16)   /* Quota stored in
                                                          a system file */

                   /* Flags in dqi_valid that indicate which fields in
                      dqinfo structure are valid. */

                   #define IIF_BGRACE  1
                   #define IIF_IGRACE  2
                   #define IIF_FLAGS   4
                   #define IIF_ALL     (IIF_BGRACE | IIF_IGRACE | IIF_FLAGS)

               The  dqi_valid  field  in  the  dqinfo  structure indicates the
               entries in the structure that are valid.  Currently, the kernel
               fills in all entries of the dqinfo structure and marks them all
               as valid in the dqi_valid field.  The id argument is ignored.

       Q_SETINFO (since Linux 2.4.22)
               Set information about quotafile.  The addr argument should be a
               pointer  to  a  dqinfo  structure.   The dqi_valid field of the
               dqinfo structure indicates the entries in  the  structure  that
               have  been  set  by  the caller.  This operation supersedes the
               Q_SETGRACE and Q_SETFLAGS  operations  in  the  previous  quota
               interfaces.   The  id  argument  is  ignored.   This  operation
               requires privilege (CAP_SYS_ADMIN).

       Q_GETFMT (since Linux 2.4.22)
               Get quota format used on the specified  filesystem.   The  addr
               argument  should be a pointer to a 4-byte buffer where the for-
               mat number will be stored.

       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.  The addr and id arguments are ignored.

       Q_GETSTATS (supported up to Linux 2.4.21)
               Get statistics and other generic information  about  the  quota
               subsystem.   The addr argument should be a pointer to a dqstats
               structure in which data should be stored.   This  structure  is
               defined  in  <sys/quota.h>.   The  special and id arguments are
               ignored.

               This operation is obsolete and was  removed  in  Linux  2.4.22.
               Files in /proc/sys/fs/quota/ carry the information instead.

       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 addr to be a pointer to an unsigned  int
               that  contains a combination of the following flags (defined in
               <xfs/xqm.h>):

                   #define XFS_QUOTA_UDQ_ACCT (1<<0) /* User quota
                                                        accounting */
                   #define XFS_QUOTA_UDQ_ENFD (1<<1) /* User quota limits
                                                        enforcement */
                   #define XFS_QUOTA_GDQ_ACCT (1<<2) /* Group quota
                                                        accounting */
                   #define XFS_QUOTA_GDQ_ENFD (1<<3) /* Group quota limits
                                                        enforcement */
                   #define XFS_QUOTA_PDQ_ACCT (1<<4) /* Project quota
                                                        accounting */
                   #define XFS_QUOTA_PDQ_ENFD (1<<5) /* Project quota limits
                                                        enforcement */

               This operation  requires  privilege  (CAP_SYS_ADMIN).   The  id
               argument is ignored.

       Q_XQUOTAOFF
               Turn  off quotas for an XFS filesystem.  As with 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 (using the same flags as for Q_XQUOTAON subcommand).
               This  operation  requires  privilege  (CAP_SYS_ADMIN).   The id
               argument is ignored.

       Q_XGETQUOTA
               Get disk quota limits and current usage for user id.  The  addr
               argument  is  a pointer to an fs_disk_quota structure, which is
               defined in <xfs/xqm.h> as follows:

                   /* All the blk units are in BBs (Basic Blocks) of
                      512 bytes. */

                   #define FS_DQUOT_VERSION  1  /* fs_disk_quota.d_version */

                   #define XFS_USER_QUOTA    (1<<0)  /* User quota type */
                   #define XFS_PROJ_QUOTA    (1<<1)  /* Project quota type */
                   #define XFS_GROUP_QUOTA   (1<<2)  /* Group quota type */

                   struct fs_disk_quota {
                       int8_t   d_version;   /* Version of this structure */
                       int8_t   d_flags;     /* XFS_{USER,PROJ,GROUP}_QUOTA */
                       uint16_t d_fieldmask; /* Field specifier */
                       uint32_t d_id;        /* User, project, or group ID */
                       uint64_t d_blk_hardlimit; /* Absolute limit on
                                                    disk blocks */
                       uint64_t d_blk_softlimit; /* Preferred limit on
                                                    disk blocks */
                       uint64_t d_ino_hardlimit; /* Maximum # allocated
                                                    inodes */
                       uint64_t d_ino_softlimit; /* Preferred inode limit */
                       uint64_t d_bcount;    /* # disk blocks owned by
                                                the user */
                       uint64_t d_icount;    /* # inodes owned by the user */
                       int32_t  d_itimer;    /* Zero if within inode limits */
                                             /* If not, we refuse service */
                       int32_t  d_btimer;    /* Similar to above; for
                                                disk blocks */
                       uint16_t d_iwarns;    /* # warnings issued with
                                                respect to # of inodes */
                       uint16_t d_bwarns;    /* # warnings issued with
                                                respect to disk blocks */
                       int32_t  d_padding2;  /* Padding - for future use */
                       uint64_t d_rtb_hardlimit; /* Absolute limit on realtime
                                                    (RT) disk blocks */
                       uint64_t d_rtb_softlimit; /* Preferred limit on RT
                                                    disk blocks */
                       uint64_t d_rtbcount;  /* # realtime blocks owned */
                       int32_t  d_rtbtimer;  /* Similar to above; for RT
                                                disk blocks */
                       uint16_t d_rtbwarns;  /* # warnings issued with
                                                respect to RT disk blocks */
                       int16_t  d_padding3;  /* Padding - for future use */
                       char     d_padding4[8];   /* Yet more padding */
                   };

               Unprivileged users may retrieve only their own quotas; a privi-
               leged user (CAP_SYS_ADMIN) may retrieve the quotas of any user.

       Q_XGETNEXTQUOTA (since Linux 4.6)
               This  operation  is the same as Q_XGETQUOTA, but it returns (in
               the fs_disk_quota structure pointed by addr) quota  information
               for  the  next  ID greater than or equal to id that has a quota
               set.  Note that since fs_disk_quota already has q_id field,  no
               separate  structure type is needed (in contrast with Q_GETQUOTA
               and Q_GETNEXTQUOTA commands)

       Q_XSETQLIM
               Set disk quota limits for user id.   The  addr  argument  is  a
               pointer to an fs_disk_quota structure.  This operation requires
               privilege (CAP_SYS_ADMIN).

       Q_XGETQSTAT
               Returns  XFS  filesystem-specific  quota  information  in   the
               fs_quota_stat  structure  pointed  by addr.  This is useful for
               finding out how much space is used to store quota  information,
               and  also  to  get the quota on/off status of a given local XFS
               filesystem.  The fs_quota_stat structure itself is  defined  as
               follows:

                   #define FS_QSTAT_VERSION 1  /* fs_quota_stat.qs_version */

                   struct fs_qfilestat {
                       uint64_t qfs_ino;       /* Inode number */
                       uint64_t qfs_nblks;     /* Number of BBs
                                                  512-byte-blocks */

                       uint32_t qfs_nextents;  /* Number of extents */
                   };

                   struct fs_quota_stat {
                       int8_t   qs_version; /* Version number for
                                               future changes */
                       uint16_t qs_flags; /* XFS_QUOTA_{U,P,G}DQ_{ACCT,ENFD} */
                       int8_t   qs_pad;   /* Unused */
                       struct fs_qfilestat qs_uquota;  /* User quota storage
                                                          information */
                       struct fs_qfilestat qs_gquota;  /* Group quota storage
                                                          information */
                       uint32_t qs_incoredqs;   /* Number of dquots in core */
                       int32_t  qs_btimelimit;  /* Limit for blocks timer */
                       int32_t  qs_itimelimit;  /* Limit for inodes timer */
                       int32_t  qs_rtbtimelimit;/* Limit for RT
                                                   blocks timer */
                       uint16_t qs_bwarnlimit;  /* Limit for # of warnings */
                       uint16_t qs_iwarnlimit;  /* Limit for # of warnings */
                   };

               The id argument is ignored.

       Q_XGETQSTATV
               Returns   XFS  filesystem-specific  quota  information  in  the
               fs_quota_statv pointed to by addr.  This version of the command
               uses  a  structure  with  proper versioning support, along with
               appropriate layout (all fields are naturally aligned) and  pad-
               ding  to avoiding special compat handling; it also provides the
               ability to get statistics regarding  the  project  quota  file.
               The fs_quota_statv structure itself is defined as follows:

                   #define FS_QSTATV_VERSION1 1 /* fs_quota_statv.qs_version */

                   struct fs_qfilestatv {
                       uint64_t qfs_ino;       /* Inode number */
                       uint64_t qfs_nblks;     /* Number of BBs
                                                  512-byte-blocks */
                       uint32_t qfs_nextents;  /* Number of extents */
                       uint32_t qfs_pad;       /* Pad for 8-byte alignment */
                   };

                   struct fs_quota_statv {
                       int8_t   qs_version;    /* Version for future
                                                  changes */
                       uint8_t  qs_pad1;       /* Pad for 16-bit alignment */
                       uint16_t qs_flags;      /* XFS_QUOTA_.* flags */
                       uint32_t qs_incoredqs;  /* Number of dquots incore */
                       struct fs_qfilestatv qs_uquota;  /* User quota
                                                           information */
                       struct fs_qfilestatv qs_gquota;  /* Group quota
                                                           information */
                       struct fs_qfilestatv qs_pquota;  /* Project quota
                                                           information */
                       int32_t  qs_btimelimit;   /* Limit for blocks timer */
                       int32_t  qs_itimelimit;   /* Limit for inodes timer */
                       int32_t  qs_rtbtimelimit; /* Limit for RT blocks
                                                    timer */
                       uint16_t qs_bwarnlimit;   /* Limit for # of warnings */
                       uint16_t qs_iwarnlimit;   /* Limit for # of warnings */
                       uint64_t qs_pad2[8];      /* For future proofing */
                   };

               The qs_version field of the structure should be filled with the
               version of the structure supported by the callee (for now, only
               FS_QSTAT_VERSION1  is  supported).   The  kernel  will fill the
               structure in accordance with version provided.  The id argument
               is ignored.

       Q_XQUOTARM
               Free  the  disk  space  taken by disk quotas. The addr argument
               should be a pointer to an unsigned int value  containing  flags
               (the same as in d_flags field of fs_disk_quota structure) which
               identify what types of quota should be removed (note  that  the
               quota  type  passed  in the cmd argument is ignored, but should
               remain valid in order to pass preliminary quotactl syscall han-
               dler checks).

               Quotas  must  have already been turned off.  The id argument is
               ignored.

       Q_XQUOTASYNC (since Linux 2.6.15; no-op since Linux 3.4)
               This command was an XFS quota equivalent to Q_SYNC, but  it  is
               no-op  since  Linux 3.4, as sync(1) writes quota information to
               disk now (in addition to the other filesystem metadata that  it
               writes out).  The special, id and addr arguments are ignored.

RETURN VALUE
       On success, quotactl() returns 0; on error -1 is returned, and errno is
       set to indicate the error.

ERRORS
       EACCES cmd is Q_QUOTAON, and the quota file pointed to by addr  exists,
              but is not a regular file or is not on the filesystem pointed to
              by special.

       EBUSY  cmd is Q_QUOTAON, but another Q_QUOTAON had  already  been  per-
              formed.

       EFAULT addr or special is invalid.

       EINVAL cmd or type is invalid.

       EINVAL cmd is Q_QUOTAON, but the specified quota file is corrupted.

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

       ENOSYS The kernel has not been compiled with the CONFIG_QUOTA option.

       ENOTBLK
              special is not a block device.

       EPERM  The caller lacked the required privilege (CAP_SYS_ADMIN) for the
              specified operation.

       ERANGE cmd is Q_SETQUOTA, but the specified limits are out of the range
              allowed by the quota format.

       ESRCH  No  disk quota is found for the indicated user.  Quotas have not
              been turned on for this filesystem.

       ESRCH  cmd is Q_QUOTAON, but the specified quota format was not found.

       ESRCH  cmd is Q_GETNEXTQUOTA or Q_XGETNEXTQUOTA, but  there  is  no  ID
              greater than or equal to id that has an active quota.

NOTES
       Instead  of  <xfs/xqm.h>  one  can use <linux/dqblk_xfs.h>, taking into
       account that there are several naming discrepancies:

       o  Quota enabling flags (of format  XFS_QUOTA_[UGP]DQ_{ACCT,ENFD})  are
          defined without a leading "X", as FS_QUOTA_[UGP]DQ_{ACCT,ENFD}.

       o  The  same  is true for XFS_{USER,GROUP,PROJ}_QUOTA quota type flags,
          which are defined as FS_{USER,GROUP,PROJ}_QUOTA.

       o  The  dqblk_xfs.h  header  file   defines   its   own   XQM_USRQUOTA,
          XQM_GRPQUOTA,  and  XQM_PRJQUOTA  constants  for the available quota
          types, but their values are the same as for  constants  without  the
          XQM_ prefix.

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

COLOPHON
       This  page  is  part of release 4.15 of the Linux man-pages project.  A
       description of the project, information about reporting bugs,  and  the
       latest     version     of     this    page,    can    be    found    at
       https://www.kernel.org/doc/man-pages/.

Linux                             2017-09-15                       QUOTACTL(2)
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