.\" Copyright (c) 2010, Jan Kara .\" A few pieces copyright (c) 1996 Andries Brouwer (aeb@cwi.nl) .\" and copyright 2010 (c) Michael Kerrisk .\" .\" %%%LICENSE_START(VERBATIM) .\" Permission is granted to make and distribute verbatim copies of this .\" manual provided the copyright notice and this permission notice are .\" preserved on all copies. .\" .\" Permission is granted to copy and distribute modified versions of .\" this manual under the conditions for verbatim copying, provided that .\" the entire resulting derived work is distributed under the terms of .\" a permission notice identical to this one. .\" .\" Since the Linux kernel and libraries are constantly changing, this .\" manual page may be incorrect or out-of-date. The author(s) assume .\" no responsibility for errors or omissions, or for damages resulting .\" from the use of the information contained herein. The author(s) may .\" not have taken the same level of care in the production of this .\" manual, which is licensed free of charge, as they might when working .\" professionally. .\" .\" Formatted or processed versions of this manual, if unaccompanied by .\" the source, must acknowledge the copyright and authors of this work. .\" %%%LICENSE_END .\" .TH QUOTACTL 2 2010-06-16 "Linux" "Linux Programmer's Manual" .SH NAME quotactl \- manipulate disk quotas .SH SYNOPSIS .nf .B #include .B #include .LP .BI "int quotactl(int " cmd ", const char *" special ", int " id \ ", caddr_t " addr ); .fi .SH DESCRIPTION .LP The quota system can be used to set per-user and per-group 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 one week (by default) at a time; after this time, the soft limit counts as a hard limit. The .BR quotactl () call manipulates disk quotas. The .I cmd argument indicates a command to be applied to the user or group ID specified in .IR id . To initialize the .IR cmd argument, use the .IR "QCMD(subcmd, type)" macro. The .I type value is either .BR USRQUOTA , for user quotas, or .BR GRPQUOTA , for group quotas. The .I subcmd value is described below. The .I 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 .I addr argument is the address of an optional, command-specific, data structure that is copied in or out of the system. The interpretation of .I addr is given with each command below. The .I subcmd value is one of the following: .TP 8 .B Q_QUOTAON Turn on quotas for a filesystem. The .I id argument is the identification number of the quota format to be used. Currently, there are three supported quota formats: .RS .TP 13 .BR QFMT_VFS_OLD The original quota format. .TP .BR 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. .TP .BR 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. .RE .IP The .IR 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 .BR quotacheck (8) program. This operation requires privilege .RB ( CAP_SYS_ADMIN ). .TP 8 .B Q_QUOTAOFF Turn off quotas for a filesystem. The .I addr and .I id arguments are ignored. This operation requires privilege .RB ( CAP_SYS_ADMIN ). .TP .B Q_GETQUOTA Get disk quota limits and current usage for user or group .IR id . The .I addr argument is a pointer to a .I dqblk structure defined in .IR as follows: .in +4n .nf /* 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 quota block count */ 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) .fi .in The .I dqb_valid field is a bit mask that is set to indicate the entries in the .I dqblk structure that are valid. Currently, the kernel fills in all entries of the .I dqblk structure and marks them as valid in the .I dqb_valid field. Unprivileged users may retrieve only their own quotas; a privileged user .RB ( CAP_SYS_ADMIN ) can retrieve the quotas of any user. .TP .B Q_SETQUOTA Set quota information for user or group .IR id , using the information supplied in the .I dqblk structure pointed to by .IR addr . The .I dqb_valid field of the .I dqblk structure indicates which entries in the structure have been set by the caller. This operation supersedes the .B Q_SETQLIM and .B Q_SETUSE operations in the previous quota interfaces. This operation requires privilege .RB ( CAP_SYS_ADMIN ). .TP .B Q_GETINFO Get information (like grace times) about quotafile. The .I addr argument should be a pointer to a .I dqinfo structure. This structure is defined in .IR as follows: .in +4n .nf /* 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 V1_DQF_RSQUASH 1 /* Root squash enabled */ /* Other quota formats have no dqi_flags bits defined */ /* 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) .fi .in The .I dqi_valid field in the .I dqinfo structure indicates the entries in the structure that are valid. Currently, the kernel fills in all entries of the .I dqinfo structure and marks them all as valid in the .I dqi_valid field. The .I id argument is ignored. .TP .B Q_SETINFO Set information about quotafile. The .I addr argument should be a pointer to a .I dqinfo structure. The .I dqi_valid field of the .I dqinfo structure indicates the entries in the structure that have been set by the caller. This operation supersedes the .B Q_SETGRACE and .B Q_SETFLAGS operations in the previous quota interfaces. The .I id argument is ignored. This operation requires privilege .RB ( CAP_SYS_ADMIN ). .TP .B Q_GETFMT Get quota format used on the specified filesystem. The .I addr argument should be a pointer to a 4-byte buffer where the format number will be stored. .TP .B Q_SYNC Update the on-disk copy of quota usages for a filesystem. If .I special is NULL, then all filesystems with active quotas are sync'ed. The .I addr and .I id arguments are ignored. .TP .B Q_GETSTATS Get statistics and other generic information about the quota subsystem. The .I addr argument should be a pointer to a .I dqstats structure in which data should be stored. This structure is defined in .IR . The .I special and .I id arguments are ignored. This operation is obsolete and not supported by recent kernels. .\" Q_GETSTATS was removed in kernel 2.4.22. Files in .I /proc/sys/fs/quota/ carry the information instead. .PP For XFS filesystems making use of the XFS Quota Manager (XQM), the above commands are bypassed and the following commands are used: .TP 8 .B 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 .I addr to be a pointer to an .I "unsigned int" that contains either the flags .B XFS_QUOTA_UDQ_ACCT and/or .B XFS_QUOTA_UDQ_ENFD (for user quota), or .B XFS_QUOTA_GDQ_ACCT and/or .B XFS_QUOTA_GDQ_ENFD (for group quota), as defined in .IR . This operation requires privilege .RB ( CAP_SYS_ADMIN ). .TP .B Q_XQUOTAOFF Turn off quotas for an XFS filesystem. As with .BR Q_QUOTAON , XFS filesystems expect a pointer to an .I "unsigned int" that specifies whether quota accounting and/or limit enforcement need to be turned off. This operation requires privilege .RB ( CAP_SYS_ADMIN ). .TP .B Q_XGETQUOTA Get disk quota limits and current usage for user .IR id . The .I addr argument is a pointer to an .I fs_disk_quota structure (defined in .IR ). Unprivileged users may retrieve only their own quotas; a privileged user .RB ( CAP_SYS_ADMIN ) may retrieve the quotas of any user. .TP .B Q_XSETQLIM Set disk quota limits for user .IR id . The .I addr argument is a pointer to an .I fs_disk_quota structure (defined in .IR ). This operation requires privilege .RB ( CAP_SYS_ADMIN ). .TP .B Q_XGETQSTAT Returns an .I fs_quota_stat structure containing XFS filesystem-specific quota information. This is useful for finding out how much space is used to store quota information, and also to get quotaon/off status of a given local XFS filesystem. .TP .B Q_XQUOTARM Free the disk space taken by disk quotas. Quotas must have already been turned off. .PP There is no command equivalent to .B Q_SYNC for XFS since .BR sync (1) writes quota information to disk (in addition to the other filesystem metadata that it writes out). .SH RETURN VALUE .LP On success, .BR quotactl () returns 0; on error \-1 is returned, and .I errno is set to indicate the error. .SH ERRORS .TP .B EFAULT .I addr or .I special is invalid. .TP .B EINVAL .I cmd or .I type is invalid. .TP .B ENOENT The file specified by .I special or .I addr does not exist. .TP .B ENOSYS The kernel has not been compiled with the .B CONFIG_QUOTA option. .TP .B ENOTBLK .I special is not a block device. .TP .B EPERM The caller lacked the required privilege .RB ( CAP_SYS_ADMIN ) for the specified operation. .TP .B ESRCH No disk quota is found for the indicated user. Quotas have not been turned on for this filesystem. .LP If .I cmd is .BR Q_SETQUOTA , .BR quotactl () may also set .I errno to: .TP .B ERANGE Specified limits are out of range allowed by quota format. .LP If .I cmd is .BR Q_QUOTAON , .BR quotactl () may also set .I errno to: .TP .B EACCES The quota file pointed to by .I addr exists, but is not a regular file; or, the quota file pointed to by .I addr exists, but is not on the filesystem pointed to by .IR special . .TP .B EBUSY .B Q_QUOTAON attempted, but another .B Q_QUOTAON had already been performed. .TP .B EINVAL The quota file is corrupted. .TP .B ESRCH Specified quota format was not found. .SH SEE ALSO .BR quota (1), .BR getrlimit (2), .BR quotacheck (8), .BR quotaon (8) .SH COLOPHON This page is part of release 3.74 of the Linux .I man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at \%http://www.kernel.org/doc/man\-pages/.