NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | NOTES | SEE ALSO | COLOPHON

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

NAME         top

       quotactl - manipulate disk quotas

SYNOPSIS         top

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

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

DESCRIPTION         top

       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
       indicates 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
       containing the pathname of the (mounted) block special device for the
       filesystem 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
               identification 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
               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_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
               information 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
               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
               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 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
               privileged 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 padding 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 handler checks).

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

       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 that it writes out).

RETURN VALUE         top

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

ERRORS         top

       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
              performed.

       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         top

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

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

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

       ·  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         top

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

COLOPHON         top

       This page is part of release 4.08 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                            2016-07-17                      QUOTACTL(2)