1quotactl(2) System Calls Manual quotactl(2)
2
6 quotactl - manipulate disk quotas
7
9 Standard C library (libc, -lc)
10
12 #include <sys/quota.h>
13 #include <xfs/xqm.h> /* Definition of Q_X* and XFS_QUOTA_* constants
14 (or <linux/dqblk_xfs.h>; see NOTES) */
15 int quotactl(int cmd, const char *_Nullable special, int id,
17 caddr_t addr);
18
20 The quota system can be used to set per-user, per-group, and per-
21 project limits on the amount of disk space used on a filesystem. For
22 each user and/or group, a soft limit and a hard limit can be set for
23 each filesystem. The hard limit can't be exceeded. The soft limit can
24 be exceeded, but warnings will ensue. Moreover, the user can't exceed
25 the soft limit for more than grace period duration (one week by de‐
26 fault) at a time; after this, the soft limit counts as a hard limit.
27 The quotactl() call manipulates disk quotas. The cmd argument indi‐
29 cates a command to be applied to the user or group ID specified in id.
30 To initialize the cmd argument, use the QCMD(subcmd, type) macro. The
31 type value is either USRQUOTA, for user quotas, GRPQUOTA, for group
32 quotas, or (since Linux 4.1) PRJQUOTA, for project quotas. The subcmd
33 value is described below.
34 The special argument is a pointer to a null-terminated string contain‐
36 ing the pathname of the (mounted) block special device for the filesys‐
37 tem being manipulated.
38 The addr argument is the address of an optional, command-specific, data
40 structure that is copied in or out of the system. The interpretation
41 of addr is given with each operation below.
42 The subcmd value is one of the following operations:
44 Q_QUOTAON
46 Turn on quotas for a filesystem. The id argument is the identi‐
47 fication number of the quota format to be used. Currently,
48 there are three supported quota formats:
49 QFMT_VFS_OLD The original quota format.
51 QFMT_VFS_V0 The standard VFS v0 quota format, which can handle
53 32-bit UIDs and GIDs and quota limits up to 2^42
54 bytes and 2^32 inodes.
55 QFMT_VFS_V1 A quota format that can handle 32-bit UIDs and GIDs
57 and quota limits of 2^63 - 1 bytes and 2^63 - 1 in‐
58 odes.
59 The addr argument points to the pathname of a file containing
61 the quotas for the filesystem. The quota file must exist; it is
62 normally created with the quotacheck(8) program
63 Quota information can be also stored in hidden system inodes for
65 ext4, XFS, and other filesystems if the filesystem is configured
66 so. In this case, there are no visible quota files and there is
67 no need to use quotacheck(8). Quota information is always kept
68 consistent by the filesystem and the Q_QUOTAON operation serves
69 only to enable enforcement of quota limits. The presence of
70 hidden system inodes with quota information is indicated by the
71 DQF_SYS_FILE flag in the dqi_flags field returned by the Q_GET‐
72 INFO operation.
73 This operation requires privilege (CAP_SYS_ADMIN).
75 Q_QUOTAOFF
77 Turn off quotas for a filesystem. The addr and id arguments are
78 ignored. This operation requires privilege (CAP_SYS_ADMIN).
79 Q_GETQUOTA
81 Get disk quota limits and current usage for user or group id.
82 The addr argument is a pointer to a dqblk structure defined in
83 <sys/quota.h> as follows:
84 /* uint64_t is an unsigned 64-bit integer;
86 uint32_t is an unsigned 32-bit integer */
87 struct dqblk { /* Definition since Linux 2.4.22 */
89 uint64_t dqb_bhardlimit; /* Absolute limit on disk
90 quota blocks alloc */
91 uint64_t dqb_bsoftlimit; /* Preferred limit on
92 disk quota blocks */
93 uint64_t dqb_curspace; /* Current occupied space
94 (in bytes) */
95 uint64_t dqb_ihardlimit; /* Maximum number of
96 allocated inodes */
97 uint64_t dqb_isoftlimit; /* Preferred inode limit */
98 uint64_t dqb_curinodes; /* Current number of
99 allocated inodes */
100 uint64_t dqb_btime; /* Time limit for excessive
101 disk use */
102 uint64_t dqb_itime; /* Time limit for excessive
103 files */
104 uint32_t dqb_valid; /* Bit mask of QIF_*
105 constants */
106 };
107 /* Flags in dqb_valid that indicate which fields in
109 dqblk structure are valid. */
110 #define QIF_BLIMITS 1
112 #define QIF_SPACE 2
113 #define QIF_ILIMITS 4
114 #define QIF_INODES 8
115 #define QIF_BTIME 16
116 #define QIF_ITIME 32
117 #define QIF_LIMITS (QIF_BLIMITS | QIF_ILIMITS)
118 #define QIF_USAGE (QIF_SPACE | QIF_INODES)
119 #define QIF_TIMES (QIF_BTIME | QIF_ITIME)
120 #define QIF_ALL (QIF_LIMITS | QIF_USAGE | QIF_TIMES)
121 The dqb_valid field is a bit mask that is set to indicate the
123 entries in the dqblk structure that are valid. Currently, the
124 kernel fills in all entries of the dqblk structure and marks
125 them as valid in the dqb_valid field. Unprivileged users may
126 retrieve only their own quotas; a privileged user (CAP_SYS_AD‐
127 MIN) can retrieve the quotas of any user.
128 Q_GETNEXTQUOTA (since Linux 4.6)
130 This operation is the same as Q_GETQUOTA, but it returns quota
131 information for the next ID greater than or equal to id that has
132 a quota set.
133 The addr argument is a pointer to a nextdqblk structure whose
135 fields are as for the dqblk, except for the addition of a dqb_id
136 field that is used to return the ID for which quota information
137 is being returned:
138 struct nextdqblk {
140 uint64_t dqb_bhardlimit;
141 uint64_t dqb_bsoftlimit;
142 uint64_t dqb_curspace;
143 uint64_t dqb_ihardlimit;
144 uint64_t dqb_isoftlimit;
145 uint64_t dqb_curinodes;
146 uint64_t dqb_btime;
147 uint64_t dqb_itime;
148 uint32_t dqb_valid;
149 uint32_t dqb_id;
150 };
151 Q_SETQUOTA
153 Set quota information for user or group id, using the informa‐
154 tion supplied in the dqblk structure pointed to by addr. The
155 dqb_valid field of the dqblk structure indicates which entries
156 in the structure have been set by the caller. This operation
157 supersedes the Q_SETQLIM and Q_SETUSE operations in the previous
158 quota interfaces. This operation requires privilege
159 (CAP_SYS_ADMIN).
160 Q_GETINFO (since Linux 2.4.22)
162 Get information (like grace times) about quotafile. The addr
163 argument should be a pointer to a dqinfo structure. This struc‐
164 ture is defined in <sys/quota.h> as follows:
165 /* uint64_t is an unsigned 64-bit integer;
167 uint32_t is an unsigned 32-bit integer */
168 struct dqinfo { /* Defined since Linux 2.4.22 */
170 uint64_t dqi_bgrace; /* Time before block soft limit
171 becomes hard limit */
172 uint64_t dqi_igrace; /* Time before inode soft limit
173 becomes hard limit */
174 uint32_t dqi_flags; /* Flags for quotafile
175 (DQF_*) */
176 uint32_t dqi_valid;
177 };
178 /* Bits for dqi_flags */
180 /* Quota format QFMT_VFS_OLD */
182 #define DQF_ROOT_SQUASH (1 << 0) /* Root squash enabled */
184 /* Before Linux v4.0, this had been defined
185 privately as V1_DQF_RSQUASH */
186 /* Quota format QFMT_VFS_V0 / QFMT_VFS_V1 */
188 #define DQF_SYS_FILE (1 << 16) /* Quota stored in
190 a system file */
191 /* Flags in dqi_valid that indicate which fields in
193 dqinfo structure are valid. */
194 #define IIF_BGRACE 1
196 #define IIF_IGRACE 2
197 #define IIF_FLAGS 4
198 #define IIF_ALL (IIF_BGRACE | IIF_IGRACE | IIF_FLAGS)
199 The dqi_valid field in the dqinfo structure indicates the en‐
201 tries in the structure that are valid. Currently, the kernel
202 fills in all entries of the dqinfo structure and marks them all
203 as valid in the dqi_valid field. The id argument is ignored.
204 Q_SETINFO (since Linux 2.4.22)
206 Set information about quotafile. The addr argument should be a
207 pointer to a dqinfo structure. The dqi_valid field of the
208 dqinfo structure indicates the entries in the structure that
209 have been set by the caller. This operation supersedes the
210 Q_SETGRACE and Q_SETFLAGS operations in the previous quota in‐
211 terfaces. The id argument is ignored. This operation requires
212 privilege (CAP_SYS_ADMIN).
213 Q_GETFMT (since Linux 2.4.22)
215 Get quota format used on the specified filesystem. The addr ar‐
216 gument should be a pointer to a 4-byte buffer where the format
217 number will be stored.
218 Q_SYNC Update the on-disk copy of quota usages for a filesystem. If
220 special is NULL, then all filesystems with active quotas are
221 sync'ed. The addr and id arguments are ignored.
222 Q_GETSTATS (supported up to Linux 2.4.21)
224 Get statistics and other generic information about the quota
225 subsystem. The addr argument should be a pointer to a dqstats
226 structure in which data should be stored. This structure is de‐
227 fined in <sys/quota.h>. The special and id arguments are ig‐
228 nored.
229 This operation is obsolete and was removed in Linux 2.4.22.
231 Files in /proc/sys/fs/quota/ carry the information instead.
232 For XFS filesystems making use of the XFS Quota Manager (XQM), the
234 above operations are bypassed and the following operations are used:
235 Q_XQUOTAON
237 Turn on quotas for an XFS filesystem. XFS provides the ability
238 to turn on/off quota limit enforcement with quota accounting.
239 Therefore, XFS expects addr to be a pointer to an unsigned int
240 that contains a bitwise combination of the following flags (de‐
241 fined in <xfs/xqm.h>):
242 XFS_QUOTA_UDQ_ACCT /* User quota accounting */
244 XFS_QUOTA_UDQ_ENFD /* User quota limits enforcement */
245 XFS_QUOTA_GDQ_ACCT /* Group quota accounting */
246 XFS_QUOTA_GDQ_ENFD /* Group quota limits enforcement */
247 XFS_QUOTA_PDQ_ACCT /* Project quota accounting */
248 XFS_QUOTA_PDQ_ENFD /* Project quota limits enforcement */
249 This operation requires privilege (CAP_SYS_ADMIN). The id argu‐
251 ment is ignored.
252 Q_XQUOTAOFF
254 Turn off quotas for an XFS filesystem. As with Q_QUOTAON, XFS
255 filesystems expect a pointer to an unsigned int that specifies
256 whether quota accounting and/or limit enforcement need to be
257 turned off (using the same flags as for Q_XQUOTAON operation).
258 This operation requires privilege (CAP_SYS_ADMIN). The id argu‐
259 ment is ignored.
260 Q_XGETQUOTA
262 Get disk quota limits and current usage for user id. The addr
263 argument is a pointer to an fs_disk_quota structure, which is
264 defined in <xfs/xqm.h> as follows:
265 /* All the blk units are in BBs (Basic Blocks) of
267 512 bytes. */
268 #define FS_DQUOT_VERSION 1 /* fs_disk_quota.d_version */
270 #define XFS_USER_QUOTA (1<<0) /* User quota type */
272 #define XFS_PROJ_QUOTA (1<<1) /* Project quota type */
273 #define XFS_GROUP_QUOTA (1<<2) /* Group quota type */
274 struct fs_disk_quota {
276 int8_t d_version; /* Version of this structure */
277 int8_t d_flags; /* XFS_{USER,PROJ,GROUP}_QUOTA */
278 uint16_t d_fieldmask; /* Field specifier */
279 uint32_t d_id; /* User, project, or group ID */
280 uint64_t d_blk_hardlimit; /* Absolute limit on
281 disk blocks */
282 uint64_t d_blk_softlimit; /* Preferred limit on
283 disk blocks */
284 uint64_t d_ino_hardlimit; /* Maximum # allocated
285 inodes */
286 uint64_t d_ino_softlimit; /* Preferred inode limit */
287 uint64_t d_bcount; /* # disk blocks owned by
288 the user */
289 uint64_t d_icount; /* # inodes owned by the user */
290 int32_t d_itimer; /* Zero if within inode limits */
291 /* If not, we refuse service */
292 int32_t d_btimer; /* Similar to above; for
293 disk blocks */
294 uint16_t d_iwarns; /* # warnings issued with
295 respect to # of inodes */
296 uint16_t d_bwarns; /* # warnings issued with
297 respect to disk blocks */
298 int32_t d_padding2; /* Padding - for future use */
299 uint64_t d_rtb_hardlimit; /* Absolute limit on realtime
300 (RT) disk blocks */
301 uint64_t d_rtb_softlimit; /* Preferred limit on RT
302 disk blocks */
303 uint64_t d_rtbcount; /* # realtime blocks owned */
304 int32_t d_rtbtimer; /* Similar to above; for RT
305 disk blocks */
306 uint16_t d_rtbwarns; /* # warnings issued with
307 respect to RT disk blocks */
308 int16_t d_padding3; /* Padding - for future use */
309 char d_padding4[8]; /* Yet more padding */
310 };
311 Unprivileged users may retrieve only their own quotas; a privi‐
313 leged user (CAP_SYS_ADMIN) may retrieve the quotas of any user.
314 Q_XGETNEXTQUOTA (since Linux 4.6)
316 This operation is the same as Q_XGETQUOTA, but it returns (in
317 the fs_disk_quota structure pointed by addr) quota information
318 for the next ID greater than or equal to id that has a quota
319 set. Note that since fs_disk_quota already has q_id field, no
320 separate structure type is needed (in contrast with Q_GETQUOTA
321 and Q_GETNEXTQUOTA operations)
322 Q_XSETQLIM
324 Set disk quota limits for user id. The addr argument is a
325 pointer to an fs_disk_quota structure. This operation requires
326 privilege (CAP_SYS_ADMIN).
327 Q_XGETQSTAT
329 Returns XFS filesystem-specific quota information in the
330 fs_quota_stat structure pointed by addr. This is useful for
331 finding out how much space is used to store quota information,
332 and also to get the quota on/off status of a given local XFS
333 filesystem. The fs_quota_stat structure itself is defined as
334 follows:
335 #define FS_QSTAT_VERSION 1 /* fs_quota_stat.qs_version */
337 struct fs_qfilestat {
339 uint64_t qfs_ino; /* Inode number */
340 uint64_t qfs_nblks; /* Number of BBs
341 512-byte-blocks */
342 uint32_t qfs_nextents; /* Number of extents */
343 };
344 struct fs_quota_stat {
346 int8_t qs_version; /* Version number for
347 future changes */
348 uint16_t qs_flags; /* XFS_QUOTA_{U,P,G}DQ_{ACCT,ENFD} */
349 int8_t qs_pad; /* Unused */
350 struct fs_qfilestat qs_uquota; /* User quota storage
351 information */
352 struct fs_qfilestat qs_gquota; /* Group quota storage
353 information */
354 uint32_t qs_incoredqs; /* Number of dquots in core */
355 int32_t qs_btimelimit; /* Limit for blocks timer */
356 int32_t qs_itimelimit; /* Limit for inodes timer */
357 int32_t qs_rtbtimelimit;/* Limit for RT
358 blocks timer */
359 uint16_t qs_bwarnlimit; /* Limit for # of warnings */
360 uint16_t qs_iwarnlimit; /* Limit for # of warnings */
361 };
362 The id argument is ignored.
364 Q_XGETQSTATV
366 Returns XFS filesystem-specific quota information in the
367 fs_quota_statv pointed to by addr. This version of the opera‐
368 tion uses a structure with proper versioning support, along with
369 appropriate layout (all fields are naturally aligned) and pad‐
370 ding to avoiding special compat handling; it also provides the
371 ability to get statistics regarding the project quota file. The
372 fs_quota_statv structure itself is defined as follows:
373 #define FS_QSTATV_VERSION1 1 /* fs_quota_statv.qs_version */
375 struct fs_qfilestatv {
377 uint64_t qfs_ino; /* Inode number */
378 uint64_t qfs_nblks; /* Number of BBs
379 512-byte-blocks */
380 uint32_t qfs_nextents; /* Number of extents */
381 uint32_t qfs_pad; /* Pad for 8-byte alignment */
382 };
383 struct fs_quota_statv {
385 int8_t qs_version; /* Version for future
386 changes */
387 uint8_t qs_pad1; /* Pad for 16-bit alignment */
388 uint16_t qs_flags; /* XFS_QUOTA_.* flags */
389 uint32_t qs_incoredqs; /* Number of dquots incore */
390 struct fs_qfilestatv qs_uquota; /* User quota
391 information */
392 struct fs_qfilestatv qs_gquota; /* Group quota
393 information */
394 struct fs_qfilestatv qs_pquota; /* Project quota
395 information */
396 int32_t qs_btimelimit; /* Limit for blocks timer */
397 int32_t qs_itimelimit; /* Limit for inodes timer */
398 int32_t qs_rtbtimelimit; /* Limit for RT blocks
399 timer */
400 uint16_t qs_bwarnlimit; /* Limit for # of warnings */
401 uint16_t qs_iwarnlimit; /* Limit for # of warnings */
402 uint64_t qs_pad2[8]; /* For future proofing */
403 };
404 The qs_version field of the structure should be filled with the
406 version of the structure supported by the callee (for now, only
407 FS_QSTAT_VERSION1 is supported). The kernel will fill the
408 structure in accordance with version provided. The id argument
409 is ignored.
410 Q_XQUOTARM (buggy until Linux 3.16)
412 Free the disk space taken by disk quotas. The addr argument
413 should be a pointer to an unsigned int value containing flags
414 (the same as in d_flags field of fs_disk_quota structure) which
415 identify what types of quota should be removed. (Note that the
416 quota type passed in the cmd argument is ignored, but should re‐
417 main valid in order to pass preliminary quotactl syscall handler
418 checks.)
419 Quotas must have already been turned off. The id argument is
421 ignored.
422 Q_XQUOTASYNC (since Linux 2.6.15; no-op since Linux 3.4)
424 This operation was an XFS quota equivalent to Q_SYNC, but it is
425 no-op since Linux 3.4, as sync(1) writes quota information to
426 disk now (in addition to the other filesystem metadata that it
427 writes out). The special, id and addr arguments are ignored.
428
430 On success, quotactl() returns 0; on error -1 is returned, and errno is
431 set to indicate the error.
432
434 EACCES cmd is Q_QUOTAON, and the quota file pointed to by addr exists,
435 but is not a regular file or is not on the filesystem pointed to
436 by special.
437 EBUSY cmd is Q_QUOTAON, but another Q_QUOTAON had already been per‐
439 formed.
440 EFAULT addr or special is invalid.
442 EINVAL cmd or type is invalid.
444 EINVAL cmd is Q_QUOTAON, but the specified quota file is corrupted.
446 EINVAL (since Linux 5.5)
448 cmd is Q_XQUOTARM, but addr does not point to valid quota types.
449 ENOENT The file specified by special or addr does not exist.
451 ENOSYS The kernel has not been compiled with the CONFIG_QUOTA option.
453 ENOTBLK
455 special is not a block device.
456 EPERM The caller lacked the required privilege (CAP_SYS_ADMIN) for the
458 specified operation.
459 ERANGE cmd is Q_SETQUOTA, but the specified limits are out of the range
461 allowed by the quota format.
462 ESRCH No disk quota is found for the indicated user. Quotas have not
464 been turned on for this filesystem.
465 ESRCH cmd is Q_QUOTAON, but the specified quota format was not found.
467 ESRCH cmd is Q_GETNEXTQUOTA or Q_XGETNEXTQUOTA, but there is no ID
469 greater than or equal to id that has an active quota.
470
472 Instead of <xfs/xqm.h> one can use <linux/dqblk_xfs.h>, taking into ac‐
473 count that there are several naming discrepancies:
474 • Quota enabling flags (of format XFS_QUOTA_[UGP]DQ_{ACCT,ENFD}) are
476 defined without a leading "X", as FS_QUOTA_[UGP]DQ_{ACCT,ENFD}.
477 • The same is true for XFS_{USER,GROUP,PROJ}_QUOTA quota type flags,
479 which are defined as FS_{USER,GROUP,PROJ}_QUOTA.
480 • The dqblk_xfs.h header file defines its own XQM_USRQUOTA, XQM_GR‐
482 PQUOTA, and XQM_PRJQUOTA constants for the available quota types,
483 but their values are the same as for constants without the XQM_ pre‐
484 fix.
485
487 quota(1), getrlimit(2), quotacheck(8), quotaon(8)
488Linux man-pages 6.05 2023-05-03 quotactl(2)