bionic (2) quotactl.2.gz

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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 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.

       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 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

       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

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

COLOPHON

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