QUOTACTL(2)



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  de-
       fault) 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 operation below.

       The subcmd value is one of the following operations:

       Q_QUOTAON
              Turn on quotas for a filesystem.  The id argument is the identi-
              fication  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

              Quota information can be also stored in hidden system inodes for
              ext4, XFS, and other filesystems if the filesystem is configured
              so.  In this case, there are no visible quota files and there is
              no need to use quotacheck(8).  Quota information is always  kept
              consistent  by the filesystem and the Q_QUOTAON operation serves
              only to enable enforcement of quota  limits.   The  presence  of
              hidden  system inodes with quota information is indicated by the
              DQF_SYS_FILE flag in the dqi_flags field returned by the  Q_GET-
              INFO operation.

              This operation 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_AD-
              MIN) 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 previous
              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 struc-
              ture 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  en-
              tries  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 in-
              terfaces.  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 ar-
              gument should be a pointer to a 4-byte buffer where  the  format
              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 de-
              fined in <sys/quota.h>.  The special and id  arguments  are  ig-
              nored.

              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 operations are bypassed and the following operations 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 bit-wise combination of the following flags (de-
              fined in <xfs/xqm.h>):

                  XFS_QUOTA_UDQ_ACCT  /* User quota accounting */
                  XFS_QUOTA_UDQ_ENFD  /* User quota limits enforcement */
                  XFS_QUOTA_GDQ_ACCT  /* Group quota accounting */
                  XFS_QUOTA_GDQ_ENFD  /* Group quota limits enforcement */
                  XFS_QUOTA_PDQ_ACCT  /* Project quota accounting */
                  XFS_QUOTA_PDQ_ENFD  /* Project quota limits enforcement */

              This operation requires privilege (CAP_SYS_ADMIN).  The id argu-
              ment 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 operation).
              This operation requires privilege (CAP_SYS_ADMIN).  The id argu-
              ment 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 operations)

       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 opera-
              tion 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  (since Linux 3.16)
              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 re-
              main valid in order to pass preliminary quotactl syscall handler
              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  operation 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.

       EINVAL (since Linux 5.5)
              cmd is Q_XQUOTARM, but addr does not point to valid quota types.

       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 ac-
       count 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_GR-
          PQUOTA, and XQM_PRJQUOTA constants for the  available  quota  types,
          but their values are the same as for constants without the XQM_ pre-
          fix.

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

COLOPHON
       This page is part of release 5.07 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                             2020-04-11                       QUOTACTL(2)

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