1QUOTACTL(2) Linux Programmer's Manual QUOTACTL(2)
2
6 quotactl - manipulate disk quotas
7
9 #include <sys/quota.h>
10 #include <xfs/xqm.h> /* Definition of Q_X* and XFS_QUOTA_* constants
11 (or <linux/dqblk_xfs.h>; see NOTES) */
12 int quotactl(int cmd, const char *special, int id, caddr_t addr);
14
16 The quota system can be used to set per-user, per-group, and per-
17 project limits on the amount of disk space used on a filesystem. For
18 each user and/or group, a soft limit and a hard limit can be set for
19 each filesystem. The hard limit can't be exceeded. The soft limit can
20 be exceeded, but warnings will ensue. Moreover, the user can't exceed
21 the soft limit for more than grace period duration (one week by de‐
22 fault) at a time; after this, the soft limit counts as a hard limit.
23 The quotactl() call manipulates disk quotas. The cmd argument indi‐
25 cates a command to be applied to the user or group ID specified in id.
26 To initialize the cmd argument, use the QCMD(subcmd, type) macro. The
27 type value is either USRQUOTA, for user quotas, GRPQUOTA, for group
28 quotas, or (since Linux 4.1) PRJQUOTA, for project quotas. The subcmd
29 value is described below.
30 The special argument is a pointer to a null-terminated string contain‐
32 ing the pathname of the (mounted) block special device for the filesys‐
33 tem being manipulated.
34 The addr argument is the address of an optional, command-specific, data
36 structure that is copied in or out of the system. The interpretation
37 of addr is given with each operation below.
38 The subcmd value is one of the following operations:
40 Q_QUOTAON
42 Turn on quotas for a filesystem. The id argument is the identi‐
43 fication number of the quota format to be used. Currently,
44 there are three supported quota formats:
45 QFMT_VFS_OLD The original quota format.
47 QFMT_VFS_V0 The standard VFS v0 quota format, which can handle
49 32-bit UIDs and GIDs and quota limits up to 2^42
50 bytes and 2^32 inodes.
51 QFMT_VFS_V1 A quota format that can handle 32-bit UIDs and GIDs
53 and quota limits of 2^64 bytes and 2^64 inodes.
54 The addr argument points to the pathname of a file containing
56 the quotas for the filesystem. The quota file must exist; it is
57 normally created with the quotacheck(8) program
58 Quota information can be also stored in hidden system inodes for
60 ext4, XFS, and other filesystems if the filesystem is configured
61 so. In this case, there are no visible quota files and there is
62 no need to use quotacheck(8). Quota information is always kept
63 consistent by the filesystem and the Q_QUOTAON operation serves
64 only to enable enforcement of quota limits. The presence of
65 hidden system inodes with quota information is indicated by the
66 DQF_SYS_FILE flag in the dqi_flags field returned by the Q_GET‐
67 INFO operation.
68 This operation requires privilege (CAP_SYS_ADMIN).
70 Q_QUOTAOFF
72 Turn off quotas for a filesystem. The addr and id arguments are
73 ignored. This operation requires privilege (CAP_SYS_ADMIN).
74 Q_GETQUOTA
76 Get disk quota limits and current usage for user or group id.
77 The addr argument is a pointer to a dqblk structure defined in
78 <sys/quota.h> as follows:
79 /* uint64_t is an unsigned 64-bit integer;
81 uint32_t is an unsigned 32-bit integer */
82 struct dqblk { /* Definition since Linux 2.4.22 */
84 uint64_t dqb_bhardlimit; /* Absolute limit on disk
85 quota blocks alloc */
86 uint64_t dqb_bsoftlimit; /* Preferred limit on
87 disk quota blocks */
88 uint64_t dqb_curspace; /* Current occupied space
89 (in bytes) */
90 uint64_t dqb_ihardlimit; /* Maximum number of
91 allocated inodes */
92 uint64_t dqb_isoftlimit; /* Preferred inode limit */
93 uint64_t dqb_curinodes; /* Current number of
94 allocated inodes */
95 uint64_t dqb_btime; /* Time limit for excessive
96 disk use */
97 uint64_t dqb_itime; /* Time limit for excessive
98 files */
99 uint32_t dqb_valid; /* Bit mask of QIF_*
100 constants */
101 };
102 /* Flags in dqb_valid that indicate which fields in
104 dqblk structure are valid. */
105 #define QIF_BLIMITS 1
107 #define QIF_SPACE 2
108 #define QIF_ILIMITS 4
109 #define QIF_INODES 8
110 #define QIF_BTIME 16
111 #define QIF_ITIME 32
112 #define QIF_LIMITS (QIF_BLIMITS | QIF_ILIMITS)
113 #define QIF_USAGE (QIF_SPACE | QIF_INODES)
114 #define QIF_TIMES (QIF_BTIME | QIF_ITIME)
115 #define QIF_ALL (QIF_LIMITS | QIF_USAGE | QIF_TIMES)
116 The dqb_valid field is a bit mask that is set to indicate the
118 entries in the dqblk structure that are valid. Currently, the
119 kernel fills in all entries of the dqblk structure and marks
120 them as valid in the dqb_valid field. Unprivileged users may
121 retrieve only their own quotas; a privileged user (CAP_SYS_AD‐
122 MIN) can retrieve the quotas of any user.
123 Q_GETNEXTQUOTA (since Linux 4.6)
125 This operation is the same as Q_GETQUOTA, but it returns quota
126 information for the next ID greater than or equal to id that has
127 a quota set.
128 The addr argument is a pointer to a nextdqblk structure whose
130 fields are as for the dqblk, except for the addition of a dqb_id
131 field that is used to return the ID for which quota information
132 is being returned:
133 struct nextdqblk {
135 uint64_t dqb_bhardlimit;
136 uint64_t dqb_bsoftlimit;
137 uint64_t dqb_curspace;
138 uint64_t dqb_ihardlimit;
139 uint64_t dqb_isoftlimit;
140 uint64_t dqb_curinodes;
141 uint64_t dqb_btime;
142 uint64_t dqb_itime;
143 uint32_t dqb_valid;
144 uint32_t dqb_id;
145 };
146 Q_SETQUOTA
148 Set quota information for user or group id, using the informa‐
149 tion supplied in the dqblk structure pointed to by addr. The
150 dqb_valid field of the dqblk structure indicates which entries
151 in the structure have been set by the caller. This operation
152 supersedes the Q_SETQLIM and Q_SETUSE operations in the previous
153 quota interfaces. This operation requires privilege
154 (CAP_SYS_ADMIN).
155 Q_GETINFO (since Linux 2.4.22)
157 Get information (like grace times) about quotafile. The addr
158 argument should be a pointer to a dqinfo structure. This struc‐
159 ture is defined in <sys/quota.h> as follows:
160 /* uint64_t is an unsigned 64-bit integer;
162 uint32_t is an unsigned 32-bit integer */
163 struct dqinfo { /* Defined since kernel 2.4.22 */
165 uint64_t dqi_bgrace; /* Time before block soft limit
166 becomes hard limit */
167 uint64_t dqi_igrace; /* Time before inode soft limit
168 becomes hard limit */
169 uint32_t dqi_flags; /* Flags for quotafile
170 (DQF_*) */
171 uint32_t dqi_valid;
172 };
173 /* Bits for dqi_flags */
175 /* Quota format QFMT_VFS_OLD */
177 #define DQF_ROOT_SQUASH (1 << 0) /* Root squash enabled */
179 /* Before Linux v4.0, this had been defined
180 privately as V1_DQF_RSQUASH */
181 /* Quota format QFMT_VFS_V0 / QFMT_VFS_V1 */
183 #define DQF_SYS_FILE (1 << 16) /* Quota stored in
185 a system file */
186 /* Flags in dqi_valid that indicate which fields in
188 dqinfo structure are valid. */
189 #define IIF_BGRACE 1
191 #define IIF_IGRACE 2
192 #define IIF_FLAGS 4
193 #define IIF_ALL (IIF_BGRACE | IIF_IGRACE | IIF_FLAGS)
194 The dqi_valid field in the dqinfo structure indicates the en‐
196 tries in the structure that are valid. Currently, the kernel
197 fills in all entries of the dqinfo structure and marks them all
198 as valid in the dqi_valid field. The id argument is ignored.
199 Q_SETINFO (since Linux 2.4.22)
201 Set information about quotafile. The addr argument should be a
202 pointer to a dqinfo structure. The dqi_valid field of the
203 dqinfo structure indicates the entries in the structure that
204 have been set by the caller. This operation supersedes the
205 Q_SETGRACE and Q_SETFLAGS operations in the previous quota in‐
206 terfaces. The id argument is ignored. This operation requires
207 privilege (CAP_SYS_ADMIN).
208 Q_GETFMT (since Linux 2.4.22)
210 Get quota format used on the specified filesystem. The addr ar‐
211 gument should be a pointer to a 4-byte buffer where the format
212 number will be stored.
213 Q_SYNC Update the on-disk copy of quota usages for a filesystem. If
215 special is NULL, then all filesystems with active quotas are
216 sync'ed. The addr and id arguments are ignored.
217 Q_GETSTATS (supported up to Linux 2.4.21)
219 Get statistics and other generic information about the quota
220 subsystem. The addr argument should be a pointer to a dqstats
221 structure in which data should be stored. This structure is de‐
222 fined in <sys/quota.h>. The special and id arguments are ig‐
223 nored.
224 This operation is obsolete and was removed in Linux 2.4.22.
226 Files in /proc/sys/fs/quota/ carry the information instead.
227 For XFS filesystems making use of the XFS Quota Manager (XQM), the
229 above operations are bypassed and the following operations are used:
230 Q_XQUOTAON
232 Turn on quotas for an XFS filesystem. XFS provides the ability
233 to turn on/off quota limit enforcement with quota accounting.
234 Therefore, XFS expects addr to be a pointer to an unsigned int
235 that contains a bitwise combination of the following flags (de‐
236 fined in <xfs/xqm.h>):
237 XFS_QUOTA_UDQ_ACCT /* User quota accounting */
239 XFS_QUOTA_UDQ_ENFD /* User quota limits enforcement */
240 XFS_QUOTA_GDQ_ACCT /* Group quota accounting */
241 XFS_QUOTA_GDQ_ENFD /* Group quota limits enforcement */
242 XFS_QUOTA_PDQ_ACCT /* Project quota accounting */
243 XFS_QUOTA_PDQ_ENFD /* Project quota limits enforcement */
244 This operation requires privilege (CAP_SYS_ADMIN). The id argu‐
246 ment is ignored.
247 Q_XQUOTAOFF
249 Turn off quotas for an XFS filesystem. As with Q_QUOTAON, XFS
250 filesystems expect a pointer to an unsigned int that specifies
251 whether quota accounting and/or limit enforcement need to be
252 turned off (using the same flags as for Q_XQUOTAON operation).
253 This operation requires privilege (CAP_SYS_ADMIN). The id argu‐
254 ment is ignored.
255 Q_XGETQUOTA
257 Get disk quota limits and current usage for user id. The addr
258 argument is a pointer to an fs_disk_quota structure, which is
259 defined in <xfs/xqm.h> as follows:
260 /* All the blk units are in BBs (Basic Blocks) of
262 512 bytes. */
263 #define FS_DQUOT_VERSION 1 /* fs_disk_quota.d_version */
265 #define XFS_USER_QUOTA (1<<0) /* User quota type */
267 #define XFS_PROJ_QUOTA (1<<1) /* Project quota type */
268 #define XFS_GROUP_QUOTA (1<<2) /* Group quota type */
269 struct fs_disk_quota {
271 int8_t d_version; /* Version of this structure */
272 int8_t d_flags; /* XFS_{USER,PROJ,GROUP}_QUOTA */
273 uint16_t d_fieldmask; /* Field specifier */
274 uint32_t d_id; /* User, project, or group ID */
275 uint64_t d_blk_hardlimit; /* Absolute limit on
276 disk blocks */
277 uint64_t d_blk_softlimit; /* Preferred limit on
278 disk blocks */
279 uint64_t d_ino_hardlimit; /* Maximum # allocated
280 inodes */
281 uint64_t d_ino_softlimit; /* Preferred inode limit */
282 uint64_t d_bcount; /* # disk blocks owned by
283 the user */
284 uint64_t d_icount; /* # inodes owned by the user */
285 int32_t d_itimer; /* Zero if within inode limits */
286 /* If not, we refuse service */
287 int32_t d_btimer; /* Similar to above; for
288 disk blocks */
289 uint16_t d_iwarns; /* # warnings issued with
290 respect to # of inodes */
291 uint16_t d_bwarns; /* # warnings issued with
292 respect to disk blocks */
293 int32_t d_padding2; /* Padding - for future use */
294 uint64_t d_rtb_hardlimit; /* Absolute limit on realtime
295 (RT) disk blocks */
296 uint64_t d_rtb_softlimit; /* Preferred limit on RT
297 disk blocks */
298 uint64_t d_rtbcount; /* # realtime blocks owned */
299 int32_t d_rtbtimer; /* Similar to above; for RT
300 disk blocks */
301 uint16_t d_rtbwarns; /* # warnings issued with
302 respect to RT disk blocks */
303 int16_t d_padding3; /* Padding - for future use */
304 char d_padding4[8]; /* Yet more padding */
305 };
306 Unprivileged users may retrieve only their own quotas; a privi‐
308 leged user (CAP_SYS_ADMIN) may retrieve the quotas of any user.
309 Q_XGETNEXTQUOTA (since Linux 4.6)
311 This operation is the same as Q_XGETQUOTA, but it returns (in
312 the fs_disk_quota structure pointed by addr) quota information
313 for the next ID greater than or equal to id that has a quota
314 set. Note that since fs_disk_quota already has q_id field, no
315 separate structure type is needed (in contrast with Q_GETQUOTA
316 and Q_GETNEXTQUOTA operations)
317 Q_XSETQLIM
319 Set disk quota limits for user id. The addr argument is a
320 pointer to an fs_disk_quota structure. This operation requires
321 privilege (CAP_SYS_ADMIN).
322 Q_XGETQSTAT
324 Returns XFS filesystem-specific quota information in the
325 fs_quota_stat structure pointed by addr. This is useful for
326 finding out how much space is used to store quota information,
327 and also to get the quota on/off status of a given local XFS
328 filesystem. The fs_quota_stat structure itself is defined as
329 follows:
330 #define FS_QSTAT_VERSION 1 /* fs_quota_stat.qs_version */
332 struct fs_qfilestat {
334 uint64_t qfs_ino; /* Inode number */
335 uint64_t qfs_nblks; /* Number of BBs
336 512-byte-blocks */
337 uint32_t qfs_nextents; /* Number of extents */
338 };
339 struct fs_quota_stat {
341 int8_t qs_version; /* Version number for
342 future changes */
343 uint16_t qs_flags; /* XFS_QUOTA_{U,P,G}DQ_{ACCT,ENFD} */
344 int8_t qs_pad; /* Unused */
345 struct fs_qfilestat qs_uquota; /* User quota storage
346 information */
347 struct fs_qfilestat qs_gquota; /* Group quota storage
348 information */
349 uint32_t qs_incoredqs; /* Number of dquots in core */
350 int32_t qs_btimelimit; /* Limit for blocks timer */
351 int32_t qs_itimelimit; /* Limit for inodes timer */
352 int32_t qs_rtbtimelimit;/* Limit for RT
353 blocks timer */
354 uint16_t qs_bwarnlimit; /* Limit for # of warnings */
355 uint16_t qs_iwarnlimit; /* Limit for # of warnings */
356 };
357 The id argument is ignored.
359 Q_XGETQSTATV
361 Returns XFS filesystem-specific quota information in the
362 fs_quota_statv pointed to by addr. This version of the opera‐
363 tion uses a structure with proper versioning support, along with
364 appropriate layout (all fields are naturally aligned) and pad‐
365 ding to avoiding special compat handling; it also provides the
366 ability to get statistics regarding the project quota file. The
367 fs_quota_statv structure itself is defined as follows:
368 #define FS_QSTATV_VERSION1 1 /* fs_quota_statv.qs_version */
370 struct fs_qfilestatv {
372 uint64_t qfs_ino; /* Inode number */
373 uint64_t qfs_nblks; /* Number of BBs
374 512-byte-blocks */
375 uint32_t qfs_nextents; /* Number of extents */
376 uint32_t qfs_pad; /* Pad for 8-byte alignment */
377 };
378 struct fs_quota_statv {
380 int8_t qs_version; /* Version for future
381 changes */
382 uint8_t qs_pad1; /* Pad for 16-bit alignment */
383 uint16_t qs_flags; /* XFS_QUOTA_.* flags */
384 uint32_t qs_incoredqs; /* Number of dquots incore */
385 struct fs_qfilestatv qs_uquota; /* User quota
386 information */
387 struct fs_qfilestatv qs_gquota; /* Group quota
388 information */
389 struct fs_qfilestatv qs_pquota; /* Project quota
390 information */
391 int32_t qs_btimelimit; /* Limit for blocks timer */
392 int32_t qs_itimelimit; /* Limit for inodes timer */
393 int32_t qs_rtbtimelimit; /* Limit for RT blocks
394 timer */
395 uint16_t qs_bwarnlimit; /* Limit for # of warnings */
396 uint16_t qs_iwarnlimit; /* Limit for # of warnings */
397 uint64_t qs_pad2[8]; /* For future proofing */
398 };
399 The qs_version field of the structure should be filled with the
401 version of the structure supported by the callee (for now, only
402 FS_QSTAT_VERSION1 is supported). The kernel will fill the
403 structure in accordance with version provided. The id argument
404 is ignored.
405 Q_XQUOTARM (since Linux 3.16)
407 Free the disk space taken by disk quotas. The addr argument
408 should be a pointer to an unsigned int value containing flags
409 (the same as in d_flags field of fs_disk_quota structure) which
410 identify what types of quota should be removed. (Note that the
411 quota type passed in the cmd argument is ignored, but should re‐
412 main valid in order to pass preliminary quotactl syscall handler
413 checks.)
414 Quotas must have already been turned off. The id argument is
416 ignored.
417 Q_XQUOTASYNC (since Linux 2.6.15; no-op since Linux 3.4)
419 This operation was an XFS quota equivalent to Q_SYNC, but it is
420 no-op since Linux 3.4, as sync(1) writes quota information to
421 disk now (in addition to the other filesystem metadata that it
422 writes out). The special, id and addr arguments are ignored.
423
425 On success, quotactl() returns 0; on error -1 is returned, and errno is
426 set to indicate the error.
427
429 EACCES cmd is Q_QUOTAON, and the quota file pointed to by addr exists,
430 but is not a regular file or is not on the filesystem pointed to
431 by special.
432 EBUSY cmd is Q_QUOTAON, but another Q_QUOTAON had already been per‐
434 formed.
435 EFAULT addr or special is invalid.
437 EINVAL cmd or type is invalid.
439 EINVAL cmd is Q_QUOTAON, but the specified quota file is corrupted.
441 EINVAL (since Linux 5.5)
443 cmd is Q_XQUOTARM, but addr does not point to valid quota types.
444 ENOENT The file specified by special or addr does not exist.
446 ENOSYS The kernel has not been compiled with the CONFIG_QUOTA option.
448 ENOTBLK
450 special is not a block device.
451 EPERM The caller lacked the required privilege (CAP_SYS_ADMIN) for the
453 specified operation.
454 ERANGE cmd is Q_SETQUOTA, but the specified limits are out of the range
456 allowed by the quota format.
457 ESRCH No disk quota is found for the indicated user. Quotas have not
459 been turned on for this filesystem.
460 ESRCH cmd is Q_QUOTAON, but the specified quota format was not found.
462 ESRCH cmd is Q_GETNEXTQUOTA or Q_XGETNEXTQUOTA, but there is no ID
464 greater than or equal to id that has an active quota.
465
467 Instead of <xfs/xqm.h> one can use <linux/dqblk_xfs.h>, taking into ac‐
468 count that there are several naming discrepancies:
469 • Quota enabling flags (of format XFS_QUOTA_[UGP]DQ_{ACCT,ENFD}) are
471 defined without a leading "X", as FS_QUOTA_[UGP]DQ_{ACCT,ENFD}.
472 • The same is true for XFS_{USER,GROUP,PROJ}_QUOTA quota type flags,
474 which are defined as FS_{USER,GROUP,PROJ}_QUOTA.
475 • The dqblk_xfs.h header file defines its own XQM_USRQUOTA, XQM_GR‐
477 PQUOTA, and XQM_PRJQUOTA constants for the available quota types,
478 but their values are the same as for constants without the XQM_ pre‐
479 fix.
480
482 quota(1), getrlimit(2), quotacheck(8), quotaon(8)
483
485 This page is part of release 5.13 of the Linux man-pages project. A
486 description of the project, information about reporting bugs, and the
487 latest version of this page, can be found at
488 https://www.kernel.org/doc/man-pages/.
489Linux 2021-03-22 QUOTACTL(2)