QUOTACTL(2)               (2020-04-11)                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

     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 argu-
          ment 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 spe-
          cial 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 oper-
          ation below.

          The subcmd value is one of the following operations:

          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 for-
               mats:

               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.

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               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 con-
               taining 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 con-
               sistent 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_GETINFO 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 privi-
               lege (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_*

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                                                    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 indi-
               cate 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 addi-
               tion 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

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               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 inter-
               faces.  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.  Cur-
               rently, 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.

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          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 filesys-
               tem.  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 infor-
               mation 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 bitwise com-
               bination of the following flags (defined 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

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               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 operation).  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

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                                                    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 quo-
               tas 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 opera-
               tion 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 */

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                       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 operation uses a structure with proper versioning
               support, along with appropriate layout (all fields are
               naturally aligned) and padding to avoiding special com-
               pat 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 */

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                   };

               The qs_version field of the structure should be filled
               with the version of the structure supported by the cal-
               lee (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
               remain valid in order to pass preliminary quotactl sys-
               call handler checks.)

               Quotas must have already been turned off.  The id argu-
               ment 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 performed.

          EFAULT
               addr or special is invalid.

          EINVAL
               cmd or type is invalid.

          EINVAL
               cmd is Q_QUOTAON, but the specified quota file is cor-
               rupted.

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          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>, tak-
          ing into account that there are several naming discrepan-
          cies:

          +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 avail-
             able quota types, but their values are the same as for
             constants without the XQM_ prefix.

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

     COLOPHON
          This page is part of release 5.10 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/.

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