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> /* for XFS quotas */
11 int quotactl(int cmd, const char *special, int id, caddr_t addr);
13
15 The quota system can be used to set per-user, per-group, and per-
16 project limits on the amount of disk space used on a filesystem. For
17 each user and/or group, a soft limit and a hard limit can be set for
18 each filesystem. The hard limit can't be exceeded. The soft limit can
19 be exceeded, but warnings will ensue. Moreover, the user can't exceed
20 the soft limit for more than grace period duration (one week by de‐
21 fault) at a time; after this, the soft limit counts as a hard limit.
22 The quotactl() call manipulates disk quotas. The cmd argument indi‐
24 cates a command to be applied to the user or group ID specified in id.
25 To initialize the cmd argument, use the QCMD(subcmd, type) macro. The
26 type value is either USRQUOTA, for user quotas, GRPQUOTA, for group
27 quotas, or (since Linux 4.1) PRJQUOTA, for project quotas. The subcmd
28 value is described below.
29 The special argument is a pointer to a null-terminated string contain‐
31 ing the pathname of the (mounted) block special device for the filesys‐
32 tem being manipulated.
33 The addr argument is the address of an optional, command-specific, data
35 structure that is copied in or out of the system. The interpretation
36 of addr is given with each operation below.
37 The subcmd value is one of the following operations:
39 Q_QUOTAON
41 Turn on quotas for a filesystem. The id argument is the identi‐
42 fication number of the quota format to be used. Currently,
43 there are three supported quota formats:
44 QFMT_VFS_OLD The original quota format.
46 QFMT_VFS_V0 The standard VFS v0 quota format, which can handle
48 32-bit UIDs and GIDs and quota limits up to 2^42
49 bytes and 2^32 inodes.
50 QFMT_VFS_V1 A quota format that can handle 32-bit UIDs and GIDs
52 and quota limits of 2^64 bytes and 2^64 inodes.
53 The addr argument points to the pathname of a file containing
55 the quotas for the filesystem. The quota file must exist; it is
56 normally created with the quotacheck(8) program
57 Quota information can be also stored in hidden system inodes for
59 ext4, XFS, and other filesystems if the filesystem is configured
60 so. In this case, there are no visible quota files and there is
61 no need to use quotacheck(8). Quota information is always kept
62 consistent by the filesystem and the Q_QUOTAON operation serves
63 only to enable enforcement of quota limits. The presence of
64 hidden system inodes with quota information is indicated by the
65 DQF_SYS_FILE flag in the dqi_flags field returned by the Q_GET‐
66 INFO operation.
67 This operation requires privilege (CAP_SYS_ADMIN).
69 Q_QUOTAOFF
71 Turn off quotas for a filesystem. The addr and id arguments are
72 ignored. This operation requires privilege (CAP_SYS_ADMIN).
73 Q_GETQUOTA
75 Get disk quota limits and current usage for user or group id.
76 The addr argument is a pointer to a dqblk structure defined in
77 <sys/quota.h> as follows:
78 /* uint64_t is an unsigned 64-bit integer;
80 uint32_t is an unsigned 32-bit integer */
81 struct dqblk { /* Definition since Linux 2.4.22 */
83 uint64_t dqb_bhardlimit; /* Absolute limit on disk
84 quota blocks alloc */
85 uint64_t dqb_bsoftlimit; /* Preferred limit on
86 disk quota blocks */
87 uint64_t dqb_curspace; /* Current occupied space
88 (in bytes) */
89 uint64_t dqb_ihardlimit; /* Maximum number of
90 allocated inodes */
91 uint64_t dqb_isoftlimit; /* Preferred inode limit */
92 uint64_t dqb_curinodes; /* Current number of
93 allocated inodes */
94 uint64_t dqb_btime; /* Time limit for excessive
95 disk use */
96 uint64_t dqb_itime; /* Time limit for excessive
97 files */
98 uint32_t dqb_valid; /* Bit mask of QIF_*
99 constants */
100 };
101 /* Flags in dqb_valid that indicate which fields in
103 dqblk structure are valid. */
104 #define QIF_BLIMITS 1
106 #define QIF_SPACE 2
107 #define QIF_ILIMITS 4
108 #define QIF_INODES 8
109 #define QIF_BTIME 16
110 #define QIF_ITIME 32
111 #define QIF_LIMITS (QIF_BLIMITS | QIF_ILIMITS)
112 #define QIF_USAGE (QIF_SPACE | QIF_INODES)
113 #define QIF_TIMES (QIF_BTIME | QIF_ITIME)
114 #define QIF_ALL (QIF_LIMITS | QIF_USAGE | QIF_TIMES)
115 The dqb_valid field is a bit mask that is set to indicate the
117 entries in the dqblk structure that are valid. Currently, the
118 kernel fills in all entries of the dqblk structure and marks
119 them as valid in the dqb_valid field. Unprivileged users may
120 retrieve only their own quotas; a privileged user (CAP_SYS_AD‐
121 MIN) can retrieve the quotas of any user.
122 Q_GETNEXTQUOTA (since Linux 4.6)
124 This operation is the same as Q_GETQUOTA, but it returns quota
125 information for the next ID greater than or equal to id that has
126 a quota set.
127 The addr argument is a pointer to a nextdqblk structure whose
129 fields are as for the dqblk, except for the addition of a dqb_id
130 field that is used to return the ID for which quota information
131 is being returned:
132 struct nextdqblk {
134 uint64_t dqb_bhardlimit;
135 uint64_t dqb_bsoftlimit;
136 uint64_t dqb_curspace;
137 uint64_t dqb_ihardlimit;
138 uint64_t dqb_isoftlimit;
139 uint64_t dqb_curinodes;
140 uint64_t dqb_btime;
141 uint64_t dqb_itime;
142 uint32_t dqb_valid;
143 uint32_t dqb_id;
144 };
145 Q_SETQUOTA
147 Set quota information for user or group id, using the informa‐
148 tion supplied in the dqblk structure pointed to by addr. The
149 dqb_valid field of the dqblk structure indicates which entries
150 in the structure have been set by the caller. This operation
151 supersedes the Q_SETQLIM and Q_SETUSE operations in the previous
152 quota interfaces. This operation requires privilege
153 (CAP_SYS_ADMIN).
154 Q_GETINFO (since Linux 2.4.22)
156 Get information (like grace times) about quotafile. The addr
157 argument should be a pointer to a dqinfo structure. This struc‐
158 ture is defined in <sys/quota.h> as follows:
159 /* uint64_t is an unsigned 64-bit integer;
161 uint32_t is an unsigned 32-bit integer */
162 struct dqinfo { /* Defined since kernel 2.4.22 */
164 uint64_t dqi_bgrace; /* Time before block soft limit
165 becomes hard limit */
166 uint64_t dqi_igrace; /* Time before inode soft limit
167 becomes hard limit */
168 uint32_t dqi_flags; /* Flags for quotafile
169 (DQF_*) */
170 uint32_t dqi_valid;
171 };
172 /* Bits for dqi_flags */
174 /* Quota format QFMT_VFS_OLD */
176 #define DQF_ROOT_SQUASH (1 << 0) /* Root squash enabled */
178 /* Before Linux v4.0, this had been defined
179 privately as V1_DQF_RSQUASH */
180 /* Quota format QFMT_VFS_V0 / QFMT_VFS_V1 */
182 #define DQF_SYS_FILE (1 << 16) /* Quota stored in
184 a system file */
185 /* Flags in dqi_valid that indicate which fields in
187 dqinfo structure are valid. */
188 #define IIF_BGRACE 1
190 #define IIF_IGRACE 2
191 #define IIF_FLAGS 4
192 #define IIF_ALL (IIF_BGRACE | IIF_IGRACE | IIF_FLAGS)
193 The dqi_valid field in the dqinfo structure indicates the en‐
195 tries in the structure that are valid. Currently, the kernel
196 fills in all entries of the dqinfo structure and marks them all
197 as valid in the dqi_valid field. The id argument is ignored.
198 Q_SETINFO (since Linux 2.4.22)
200 Set information about quotafile. The addr argument should be a
201 pointer to a dqinfo structure. The dqi_valid field of the
202 dqinfo structure indicates the entries in the structure that
203 have been set by the caller. This operation supersedes the
204 Q_SETGRACE and Q_SETFLAGS operations in the previous quota in‐
205 terfaces. The id argument is ignored. This operation requires
206 privilege (CAP_SYS_ADMIN).
207 Q_GETFMT (since Linux 2.4.22)
209 Get quota format used on the specified filesystem. The addr ar‐
210 gument should be a pointer to a 4-byte buffer where the format
211 number will be stored.
212 Q_SYNC Update the on-disk copy of quota usages for a filesystem. If
214 special is NULL, then all filesystems with active quotas are
215 sync'ed. The addr and id arguments are ignored.
216 Q_GETSTATS (supported up to Linux 2.4.21)
218 Get statistics and other generic information about the quota
219 subsystem. The addr argument should be a pointer to a dqstats
220 structure in which data should be stored. This structure is de‐
221 fined in <sys/quota.h>. The special and id arguments are ig‐
222 nored.
223 This operation is obsolete and was removed in Linux 2.4.22.
225 Files in /proc/sys/fs/quota/ carry the information instead.
226 For XFS filesystems making use of the XFS Quota Manager (XQM), the
228 above operations are bypassed and the following operations are used:
229 Q_XQUOTAON
231 Turn on quotas for an XFS filesystem. XFS provides the ability
232 to turn on/off quota limit enforcement with quota accounting.
233 Therefore, XFS expects addr to be a pointer to an unsigned int
234 that contains a bitwise combination of the following flags (de‐
235 fined in <xfs/xqm.h>):
236 XFS_QUOTA_UDQ_ACCT /* User quota accounting */
238 XFS_QUOTA_UDQ_ENFD /* User quota limits enforcement */
239 XFS_QUOTA_GDQ_ACCT /* Group quota accounting */
240 XFS_QUOTA_GDQ_ENFD /* Group quota limits enforcement */
241 XFS_QUOTA_PDQ_ACCT /* Project quota accounting */
242 XFS_QUOTA_PDQ_ENFD /* Project quota limits enforcement */
243 This operation requires privilege (CAP_SYS_ADMIN). The id argu‐
245 ment is ignored.
246 Q_XQUOTAOFF
248 Turn off quotas for an XFS filesystem. As with Q_QUOTAON, XFS
249 filesystems expect a pointer to an unsigned int that specifies
250 whether quota accounting and/or limit enforcement need to be
251 turned off (using the same flags as for Q_XQUOTAON operation).
252 This operation requires privilege (CAP_SYS_ADMIN). The id argu‐
253 ment is ignored.
254 Q_XGETQUOTA
256 Get disk quota limits and current usage for user id. The addr
257 argument is a pointer to an fs_disk_quota structure, which is
258 defined in <xfs/xqm.h> as follows:
259 /* All the blk units are in BBs (Basic Blocks) of
261 512 bytes. */
262 #define FS_DQUOT_VERSION 1 /* fs_disk_quota.d_version */
264 #define XFS_USER_QUOTA (1<<0) /* User quota type */
266 #define XFS_PROJ_QUOTA (1<<1) /* Project quota type */
267 #define XFS_GROUP_QUOTA (1<<2) /* Group quota type */
268 struct fs_disk_quota {
270 int8_t d_version; /* Version of this structure */
271 int8_t d_flags; /* XFS_{USER,PROJ,GROUP}_QUOTA */
272 uint16_t d_fieldmask; /* Field specifier */
273 uint32_t d_id; /* User, project, or group ID */
274 uint64_t d_blk_hardlimit; /* Absolute limit on
275 disk blocks */
276 uint64_t d_blk_softlimit; /* Preferred limit on
277 disk blocks */
278 uint64_t d_ino_hardlimit; /* Maximum # allocated
279 inodes */
280 uint64_t d_ino_softlimit; /* Preferred inode limit */
281 uint64_t d_bcount; /* # disk blocks owned by
282 the user */
283 uint64_t d_icount; /* # inodes owned by the user */
284 int32_t d_itimer; /* Zero if within inode limits */
285 /* If not, we refuse service */
286 int32_t d_btimer; /* Similar to above; for
287 disk blocks */
288 uint16_t d_iwarns; /* # warnings issued with
289 respect to # of inodes */
290 uint16_t d_bwarns; /* # warnings issued with
291 respect to disk blocks */
292 int32_t d_padding2; /* Padding - for future use */
293 uint64_t d_rtb_hardlimit; /* Absolute limit on realtime
294 (RT) disk blocks */
295 uint64_t d_rtb_softlimit; /* Preferred limit on RT
296 disk blocks */
297 uint64_t d_rtbcount; /* # realtime blocks owned */
298 int32_t d_rtbtimer; /* Similar to above; for RT
299 disk blocks */
300 uint16_t d_rtbwarns; /* # warnings issued with
301 respect to RT disk blocks */
302 int16_t d_padding3; /* Padding - for future use */
303 char d_padding4[8]; /* Yet more padding */
304 };
305 Unprivileged users may retrieve only their own quotas; a privi‐
307 leged user (CAP_SYS_ADMIN) may retrieve the quotas of any user.
308 Q_XGETNEXTQUOTA (since Linux 4.6)
310 This operation is the same as Q_XGETQUOTA, but it returns (in
311 the fs_disk_quota structure pointed by addr) quota information
312 for the next ID greater than or equal to id that has a quota
313 set. Note that since fs_disk_quota already has q_id field, no
314 separate structure type is needed (in contrast with Q_GETQUOTA
315 and Q_GETNEXTQUOTA operations)
316 Q_XSETQLIM
318 Set disk quota limits for user id. The addr argument is a
319 pointer to an fs_disk_quota structure. This operation requires
320 privilege (CAP_SYS_ADMIN).
321 Q_XGETQSTAT
323 Returns XFS filesystem-specific quota information in the
324 fs_quota_stat structure pointed by addr. This is useful for
325 finding out how much space is used to store quota information,
326 and also to get the quota on/off status of a given local XFS
327 filesystem. The fs_quota_stat structure itself is defined as
328 follows:
329 #define FS_QSTAT_VERSION 1 /* fs_quota_stat.qs_version */
331 struct fs_qfilestat {
333 uint64_t qfs_ino; /* Inode number */
334 uint64_t qfs_nblks; /* Number of BBs
335 512-byte-blocks */
336 uint32_t qfs_nextents; /* Number of extents */
337 };
338 struct fs_quota_stat {
340 int8_t qs_version; /* Version number for
341 future changes */
342 uint16_t qs_flags; /* XFS_QUOTA_{U,P,G}DQ_{ACCT,ENFD} */
343 int8_t qs_pad; /* Unused */
344 struct fs_qfilestat qs_uquota; /* User quota storage
345 information */
346 struct fs_qfilestat qs_gquota; /* Group quota storage
347 information */
348 uint32_t qs_incoredqs; /* Number of dquots in core */
349 int32_t qs_btimelimit; /* Limit for blocks timer */
350 int32_t qs_itimelimit; /* Limit for inodes timer */
351 int32_t qs_rtbtimelimit;/* Limit for RT
352 blocks timer */
353 uint16_t qs_bwarnlimit; /* Limit for # of warnings */
354 uint16_t qs_iwarnlimit; /* Limit for # of warnings */
355 };
356 The id argument is ignored.
358 Q_XGETQSTATV
360 Returns XFS filesystem-specific quota information in the
361 fs_quota_statv pointed to by addr. This version of the opera‐
362 tion uses a structure with proper versioning support, along with
363 appropriate layout (all fields are naturally aligned) and pad‐
364 ding to avoiding special compat handling; it also provides the
365 ability to get statistics regarding the project quota file. The
366 fs_quota_statv structure itself is defined as follows:
367 #define FS_QSTATV_VERSION1 1 /* fs_quota_statv.qs_version */
369 struct fs_qfilestatv {
371 uint64_t qfs_ino; /* Inode number */
372 uint64_t qfs_nblks; /* Number of BBs
373 512-byte-blocks */
374 uint32_t qfs_nextents; /* Number of extents */
375 uint32_t qfs_pad; /* Pad for 8-byte alignment */
376 };
377 struct fs_quota_statv {
379 int8_t qs_version; /* Version for future
380 changes */
381 uint8_t qs_pad1; /* Pad for 16-bit alignment */
382 uint16_t qs_flags; /* XFS_QUOTA_.* flags */
383 uint32_t qs_incoredqs; /* Number of dquots incore */
384 struct fs_qfilestatv qs_uquota; /* User quota
385 information */
386 struct fs_qfilestatv qs_gquota; /* Group quota
387 information */
388 struct fs_qfilestatv qs_pquota; /* Project quota
389 information */
390 int32_t qs_btimelimit; /* Limit for blocks timer */
391 int32_t qs_itimelimit; /* Limit for inodes timer */
392 int32_t qs_rtbtimelimit; /* Limit for RT blocks
393 timer */
394 uint16_t qs_bwarnlimit; /* Limit for # of warnings */
395 uint16_t qs_iwarnlimit; /* Limit for # of warnings */
396 uint64_t qs_pad2[8]; /* For future proofing */
397 };
398 The qs_version field of the structure should be filled with the
400 version of the structure supported by the callee (for now, only
401 FS_QSTAT_VERSION1 is supported). The kernel will fill the
402 structure in accordance with version provided. The id argument
403 is ignored.
404 Q_XQUOTARM (since Linux 3.16)
406 Free the disk space taken by disk quotas. The addr argument
407 should be a pointer to an unsigned int value containing flags
408 (the same as in d_flags field of fs_disk_quota structure) which
409 identify what types of quota should be removed. (Note that the
410 quota type passed in the cmd argument is ignored, but should re‐
411 main valid in order to pass preliminary quotactl syscall handler
412 checks.)
413 Quotas must have already been turned off. The id argument is
415 ignored.
416 Q_XQUOTASYNC (since Linux 2.6.15; no-op since Linux 3.4)
418 This operation was an XFS quota equivalent to Q_SYNC, but it is
419 no-op since Linux 3.4, as sync(1) writes quota information to
420 disk now (in addition to the other filesystem metadata that it
421 writes out). The special, id and addr arguments are ignored.
422
424 On success, quotactl() returns 0; on error -1 is returned, and errno is
425 set to indicate the error.
426
428 EACCES cmd is Q_QUOTAON, and the quota file pointed to by addr exists,
429 but is not a regular file or is not on the filesystem pointed to
430 by special.
431 EBUSY cmd is Q_QUOTAON, but another Q_QUOTAON had already been per‐
433 formed.
434 EFAULT addr or special is invalid.
436 EINVAL cmd or type is invalid.
438 EINVAL cmd is Q_QUOTAON, but the specified quota file is corrupted.
440 EINVAL (since Linux 5.5)
442 cmd is Q_XQUOTARM, but addr does not point to valid quota types.
443 ENOENT The file specified by special or addr does not exist.
445 ENOSYS The kernel has not been compiled with the CONFIG_QUOTA option.
447 ENOTBLK
449 special is not a block device.
450 EPERM The caller lacked the required privilege (CAP_SYS_ADMIN) for the
452 specified operation.
453 ERANGE cmd is Q_SETQUOTA, but the specified limits are out of the range
455 allowed by the quota format.
456 ESRCH No disk quota is found for the indicated user. Quotas have not
458 been turned on for this filesystem.
459 ESRCH cmd is Q_QUOTAON, but the specified quota format was not found.
461 ESRCH cmd is Q_GETNEXTQUOTA or Q_XGETNEXTQUOTA, but there is no ID
463 greater than or equal to id that has an active quota.
464
466 Instead of <xfs/xqm.h> one can use <linux/dqblk_xfs.h>, taking into ac‐
467 count that there are several naming discrepancies:
468 • Quota enabling flags (of format XFS_QUOTA_[UGP]DQ_{ACCT,ENFD}) are
470 defined without a leading "X", as FS_QUOTA_[UGP]DQ_{ACCT,ENFD}.
471 • The same is true for XFS_{USER,GROUP,PROJ}_QUOTA quota type flags,
473 which are defined as FS_{USER,GROUP,PROJ}_QUOTA.
474 • The dqblk_xfs.h header file defines its own XQM_USRQUOTA, XQM_GR‐
476 PQUOTA, and XQM_PRJQUOTA constants for the available quota types,
477 but their values are the same as for constants without the XQM_ pre‐
478 fix.
479
481 quota(1), getrlimit(2), quotacheck(8), quotaon(8)
482
484 This page is part of release 5.10 of the Linux man-pages project. A
485 description of the project, information about reporting bugs, and the
486 latest version of this page, can be found at
487 https://www.kernel.org/doc/man-pages/.
488Linux 2020-04-11 QUOTACTL(2)