man2/quotactl.2

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  27 .TH QUOTACTL 2 2020-04-11 "Linux" "Linux Programmer's Manual"
  28 .SH NAME
  29 quotactl \- manipulate disk quotas
  30 .SH SYNOPSIS
  31 .nf
  32 .B #include <sys/quota.h>
  33 .B #include <xfs/xqm.h> /* for XFS quotas */
  34 .PP
  35 .BI "int quotactl(int " cmd ", const char *" special ", int " id \
  36 ", caddr_t " addr );
  37 .fi
  38 .SH DESCRIPTION
  39 .PP
  40 The quota system can be used to set per-user, per-group, and per-project limits
  41 on the amount of disk space used on a filesystem.
  42 For each user and/or group,
  43 a soft limit and a hard limit can be set for each filesystem.
  44 The hard limit can't be exceeded.
  45 The soft limit can be exceeded, but warnings will ensue.
  46 Moreover, the user can't exceed the soft limit for more than grace period
  47 duration (one week by default) at a time;
  48 after this, the soft limit counts as a hard limit.
  49 .PP
  50 The
  51 .BR quotactl ()
  52 call manipulates disk quotas.
  53 The
  54 .I cmd
  55 argument indicates a command to be applied to the user or
  56 group ID specified in
  57 .IR id .
  58 To initialize the
  59 .IR cmd
  60 argument, use the
  61 .IR "QCMD(subcmd, type)"
  62 macro.
  63 The
  64 .I type
  65 value is either
  66 .BR USRQUOTA ,
  67 for user quotas,
  68 .BR GRPQUOTA ,
  69 for group quotas, or (since Linux 4.1)
  70 .\" 847aac644e92e5624f2c153bab409bf713d5ff9a
  71 .BR PRJQUOTA ,
  72 for project quotas.
  73 The
  74 .I subcmd
  75 value is described below.
  76 .PP
  77 The
  78 .I special
  79 argument is a pointer to a null-terminated string containing the pathname
  80 of the (mounted) block special device for the filesystem being manipulated.
  81 .PP
  82 The
  83 .I addr
  84 argument is the address of an optional, command-specific, data structure
  85 that is copied in or out of the system.
  86 The interpretation of
  87 .I addr
  88 is given with each operation below.
  89 .PP
  90 The
  91 .I subcmd
  92 value is one of the following operations:
  93 .TP
  94 .B Q_QUOTAON
  95 Turn on quotas for a filesystem.
  96 The
  97 .I id
  98 argument is the identification number of the quota format to be used.
  99 Currently, there are three supported quota formats:
 100 .RS
 101 .TP 13
 102 .BR QFMT_VFS_OLD
 103 The original quota format.
 104 .TP
 105 .BR QFMT_VFS_V0
 106 The standard VFS v0 quota format, which can handle 32-bit UIDs and GIDs
 107 and quota limits up to 2^42 bytes and 2^32 inodes.
 108 .TP
 109 .BR QFMT_VFS_V1
 110 A quota format that can handle 32-bit UIDs and GIDs
 111 and quota limits of 2^64 bytes and 2^64 inodes.
 112 .RE
 113 .IP
 114 The
 115 .IR addr
 116 argument points to the pathname of a file containing the quotas for
 117 the filesystem.
 118 The quota file must exist; it is normally created with the
 119 .BR quotacheck (8)
 120 program
 121 .IP
 122 Quota information can be also stored in hidden system inodes
 123 for ext4, XFS, and other filesystems if the filesystem is configured so.
 124 In this case, there are no visible quota files and there is no need to
 125 use
 126 .BR quotacheck (8).
 127 Quota information is always kept consistent by the filesystem and the
 128 .B Q_QUOTAON
 129 operation serves only to enable enforcement of quota limits.
 130 The presence of hidden
 131 system inodes with quota information is indicated by the
 132 .B DQF_SYS_FILE
 133 flag in the
 134 .I dqi_flags
 135 field returned by the
 136 .B Q_GETINFO
 137 operation.
 138 .IP
 139 This operation requires privilege
 140 .RB ( CAP_SYS_ADMIN ).
 141 .TP
 142 .B Q_QUOTAOFF
 143 Turn off quotas for a filesystem.
 144 The
 145 .I addr
 146 and
 147 .I id
 148 arguments are ignored.
 149 This operation requires privilege
 150 .RB ( CAP_SYS_ADMIN ).
 151 .TP
 152 .B Q_GETQUOTA
 153 Get disk quota limits and current usage for user or group
 154 .IR id .
 155 The
 156 .I addr
 157 argument is a pointer to a
 158 .I dqblk
 159 structure defined in
 160 .IR <sys/quota.h>
 161 as follows:
 162 .IP
 163 .in +4n
 164 .EX
 165 /* uint64_t is an unsigned 64\-bit integer;
 166    uint32_t is an unsigned 32\-bit integer */
 167
 168 struct dqblk {      /* Definition since Linux 2.4.22 */
 169     uint64_t dqb_bhardlimit;  /* Absolute limit on disk
 170                                  quota blocks alloc */
 171     uint64_t dqb_bsoftlimit;  /* Preferred limit on
 172                                  disk quota blocks */
 173     uint64_t dqb_curspace;    /* Current occupied space
 174                                  (in bytes) */
 175     uint64_t dqb_ihardlimit;  /* Maximum number of
 176                                  allocated inodes */
 177     uint64_t dqb_isoftlimit;  /* Preferred inode limit */
 178     uint64_t dqb_curinodes;   /* Current number of
 179                                  allocated inodes */
 180     uint64_t dqb_btime;       /* Time limit for excessive
 181                                  disk use */
 182     uint64_t dqb_itime;       /* Time limit for excessive
 183                                  files */
 184     uint32_t dqb_valid;       /* Bit mask of QIF_*
 185                                  constants */
 186 };
 187
 188 /* Flags in dqb_valid that indicate which fields in
 189    dqblk structure are valid. */
 190
 191 #define QIF_BLIMITS   1
 192 #define QIF_SPACE     2
 193 #define QIF_ILIMITS   4
 194 #define QIF_INODES    8
 195 #define QIF_BTIME     16
 196 #define QIF_ITIME     32
 197 #define QIF_LIMITS    (QIF_BLIMITS | QIF_ILIMITS)
 198 #define QIF_USAGE     (QIF_SPACE | QIF_INODES)
 199 #define QIF_TIMES     (QIF_BTIME | QIF_ITIME)
 200 #define QIF_ALL       (QIF_LIMITS | QIF_USAGE | QIF_TIMES)
 201 .EE
 202 .in
 203 .IP
 204 The
 205 .I dqb_valid
 206 field is a bit mask that is set to indicate the entries in the
 207 .I dqblk
 208 structure that are valid.
 209 Currently, the kernel fills in all entries of the
 210 .I dqblk
 211 structure and marks them as valid in the
 212 .I dqb_valid
 213 field.
 214 Unprivileged users may retrieve only their own quotas;
 215 a privileged user
 216 .RB ( CAP_SYS_ADMIN )
 217 can retrieve the quotas of any user.
 218 .TP
 219 .BR Q_GETNEXTQUOTA " (since Linux 4.6)"
 220 .\" commit 926132c0257a5a8d149a6a395cc3405e55420566
 221 This operation is the same as
 222 .BR Q_GETQUOTA ,
 223 but it returns quota information for the next ID greater than or equal to
 224 .IR id
 225 that has a quota set.
 226 .IP
 227 The
 228 .I addr
 229 argument is a pointer to a
 230 .I nextdqblk
 231 structure whose fields are as for the
 232 .IR dqblk ,
 233 except for the addition of a
 234 .I dqb_id
 235 field that is used to return the ID for which
 236 quota information is being returned:
 237 .IP
 238 .in +4n
 239 .EX
 240 struct nextdqblk {
 241     uint64_t dqb_bhardlimit;
 242     uint64_t dqb_bsoftlimit;
 243     uint64_t dqb_curspace;
 244     uint64_t dqb_ihardlimit;
 245     uint64_t dqb_isoftlimit;
 246     uint64_t dqb_curinodes;
 247     uint64_t dqb_btime;
 248     uint64_t dqb_itime;
 249     uint32_t dqb_valid;
 250     uint32_t dqb_id;
 251 };
 252 .EE
 253 .in
 254 .TP
 255 .B Q_SETQUOTA
 256 Set quota information for user or group
 257 .IR id ,
 258 using the information supplied in the
 259 .I dqblk
 260 structure pointed to by
 261 .IR addr .
 262 The
 263 .I dqb_valid
 264 field of the
 265 .I dqblk
 266 structure indicates which entries in the structure have been set by the caller.
 267 This operation supersedes the
 268 .B Q_SETQLIM
 269 and
 270 .B Q_SETUSE
 271 operations in the previous quota interfaces.
 272 This operation requires privilege
 273 .RB ( CAP_SYS_ADMIN ).
 274 .TP
 275 .BR Q_GETINFO " (since Linux 2.4.22)"
 276 Get information (like grace times) about quotafile.
 277 The
 278 .I addr
 279 argument should be a pointer to a
 280 .I dqinfo
 281 structure.
 282 This structure is defined in
 283 .IR <sys/quota.h>
 284 as follows:
 285 .IP
 286 .in +4n
 287 .EX
 288 /* uint64_t is an unsigned 64\-bit integer;
 289    uint32_t is an unsigned 32\-bit integer */
 290
 291 struct dqinfo {         /* Defined since kernel 2.4.22 */
 292     uint64_t dqi_bgrace;  /* Time before block soft limit
 293                              becomes hard limit */
 294     uint64_t dqi_igrace;  /* Time before inode soft limit
 295                              becomes hard limit */
 296     uint32_t dqi_flags;   /* Flags for quotafile
 297                              (DQF_*) */
 298     uint32_t dqi_valid;
 299 };
 300
 301 /* Bits for dqi_flags */
 302
 303 /* Quota format QFMT_VFS_OLD */
 304
 305 #define DQF_ROOT_SQUASH (1 << 0) /* Root squash enabled */
 306               /* Before Linux v4.0, this had been defined
 307                  privately as V1_DQF_RSQUASH */
 308
 309 /* Quota format QFMT_VFS_V0 / QFMT_VFS_V1 */
 310
 311 #define DQF_SYS_FILE    (1 << 16)   /* Quota stored in
 312                                        a system file */
 313
 314 /* Flags in dqi_valid that indicate which fields in
 315    dqinfo structure are valid. */
 316
 317 #define IIF_BGRACE  1
 318 #define IIF_IGRACE  2
 319 #define IIF_FLAGS   4
 320 #define IIF_ALL     (IIF_BGRACE | IIF_IGRACE | IIF_FLAGS)
 321 .EE
 322 .in
 323 .IP
 324 The
 325 .I dqi_valid
 326 field in the
 327 .I dqinfo
 328 structure indicates the entries in the structure that are valid.
 329 Currently, the kernel fills in all entries of the
 330 .I dqinfo
 331 structure and marks them all as valid in the
 332 .I dqi_valid
 333 field.
 334 The
 335 .I id
 336 argument is ignored.
 337 .TP
 338 .BR Q_SETINFO " (since Linux 2.4.22)"
 339 Set information about quotafile.
 340 The
 341 .I addr
 342 argument should be a pointer to a
 343 .I dqinfo
 344 structure.
 345 The
 346 .I dqi_valid
 347 field of the
 348 .I dqinfo
 349 structure indicates the entries in the structure
 350 that have been set by the caller.
 351 This operation supersedes the
 352 .B Q_SETGRACE
 353 and
 354 .B Q_SETFLAGS
 355 operations in the previous quota interfaces.
 356 The
 357 .I id
 358 argument is ignored.
 359 This operation requires privilege
 360 .RB ( CAP_SYS_ADMIN ).
 361 .TP
 362 .BR Q_GETFMT " (since Linux 2.4.22)"
 363 Get quota format used on the specified filesystem.
 364 The
 365 .I addr
 366 argument should be a pointer to a 4-byte buffer
 367 where the format number will be stored.
 368 .TP
 369 .B Q_SYNC
 370 Update the on-disk copy of quota usages for a filesystem.
 371 If
 372 .I special
 373 is NULL, then all filesystems with active quotas are sync'ed.
 374 The
 375 .I addr
 376 and
 377 .I id
 378 arguments are ignored.
 379 .TP
 380 .BR Q_GETSTATS " (supported up to Linux 2.4.21)"
 381 Get statistics and other generic information about the quota subsystem.
 382 The
 383 .I addr
 384 argument should be a pointer to a
 385 .I dqstats
 386 structure in which data should be stored.
 387 This structure is defined in
 388 .IR <sys/quota.h> .
 389 The
 390 .I special
 391 and
 392 .I id
 393 arguments are ignored.
 394 .IP
 395 This operation is obsolete and was removed in Linux 2.4.22.
 396 Files in
 397 .I /proc/sys/fs/quota/
 398 carry the information instead.
 399 .PP
 400 For XFS filesystems making use of the XFS Quota Manager (XQM),
 401 the above operations are bypassed and the following operations are used:
 402 .TP
 403 .B Q_XQUOTAON
 404 Turn on quotas for an XFS filesystem.
 405 XFS provides the ability to turn on/off quota limit enforcement
 406 with quota accounting.
 407 Therefore, XFS expects
 408 .I addr
 409 to be a pointer to an
 410 .I "unsigned int"
 411 that contains a bit-wise combination of the following flags (defined in
 412 .IR <xfs/xqm.h> ):
 413 .IP
 414 .in +4n
 415 .EX
 416 XFS_QUOTA_UDQ_ACCT  /* User quota accounting */
 417 XFS_QUOTA_UDQ_ENFD  /* User quota limits enforcement */
 418 XFS_QUOTA_GDQ_ACCT  /* Group quota accounting */
 419 XFS_QUOTA_GDQ_ENFD  /* Group quota limits enforcement */
 420 XFS_QUOTA_PDQ_ACCT  /* Project quota accounting */
 421 XFS_QUOTA_PDQ_ENFD  /* Project quota limits enforcement */
 422 .EE
 423 .in
 424 .IP
 425 This operation requires privilege
 426 .RB ( CAP_SYS_ADMIN ).
 427 The
 428 .I id
 429 argument is ignored.
 430 .TP
 431 .B Q_XQUOTAOFF
 432 Turn off quotas for an XFS filesystem.
 433 As with
 434 .BR Q_QUOTAON ,
 435 XFS filesystems expect a pointer to an
 436 .I "unsigned int"
 437 that specifies whether quota accounting and/or limit enforcement need
 438 to be turned off (using the same flags as for
 439 .B Q_XQUOTAON
 440 operation).
 441 This operation requires privilege
 442 .RB ( CAP_SYS_ADMIN ).
 443 The
 444 .I id
 445 argument is ignored.
 446 .TP
 447 .B Q_XGETQUOTA
 448 Get disk quota limits and current usage for user
 449 .IR id .
 450 The
 451 .I addr
 452 argument is a pointer to an
 453 .I fs_disk_quota
 454 structure, which is defined in
 455 .I <xfs/xqm.h>
 456 as follows:
 457 .IP
 458 .in +4n
 459 .EX
 460 /* All the blk units are in BBs (Basic Blocks) of
 461    512 bytes. */
 462
 463 #define FS_DQUOT_VERSION  1  /* fs_disk_quota.d_version */
 464
 465 #define XFS_USER_QUOTA    (1<<0)  /* User quota type */
 466 #define XFS_PROJ_QUOTA    (1<<1)  /* Project quota type */
 467 #define XFS_GROUP_QUOTA   (1<<2)  /* Group quota type */
 468
 469 struct fs_disk_quota {
 470     int8_t   d_version;   /* Version of this structure */
 471     int8_t   d_flags;     /* XFS_{USER,PROJ,GROUP}_QUOTA */
 472     uint16_t d_fieldmask; /* Field specifier */
 473     uint32_t d_id;        /* User, project, or group ID */
 474     uint64_t d_blk_hardlimit; /* Absolute limit on
 475                                  disk blocks */
 476     uint64_t d_blk_softlimit; /* Preferred limit on
 477                                  disk blocks */
 478     uint64_t d_ino_hardlimit; /* Maximum # allocated
 479                                  inodes */
 480     uint64_t d_ino_softlimit; /* Preferred inode limit */
 481     uint64_t d_bcount;    /* # disk blocks owned by
 482                              the user */
 483     uint64_t d_icount;    /* # inodes owned by the user */
 484     int32_t  d_itimer;    /* Zero if within inode limits */
 485                           /* If not, we refuse service */
 486     int32_t  d_btimer;    /* Similar to above; for
 487                              disk blocks */
 488     uint16_t d_iwarns;    /* # warnings issued with
 489                              respect to # of inodes */
 490     uint16_t d_bwarns;    /* # warnings issued with
 491                              respect to disk blocks */
 492     int32_t  d_padding2;  /* Padding - for future use */
 493     uint64_t d_rtb_hardlimit; /* Absolute limit on realtime
 494                                  (RT) disk blocks */
 495     uint64_t d_rtb_softlimit; /* Preferred limit on RT
 496                                  disk blocks */
 497     uint64_t d_rtbcount;  /* # realtime blocks owned */
 498     int32_t  d_rtbtimer;  /* Similar to above; for RT
 499                              disk blocks */
 500     uint16_t d_rtbwarns;  /* # warnings issued with
 501                              respect to RT disk blocks */
 502     int16_t  d_padding3;  /* Padding - for future use */
 503     char     d_padding4[8];   /* Yet more padding */
 504 };
 505 .EE
 506 .in
 507 .IP
 508 Unprivileged users may retrieve only their own quotas;
 509 a privileged user
 510 .RB ( CAP_SYS_ADMIN )
 511 may retrieve the quotas of any user.
 512 .TP
 513 .BR Q_XGETNEXTQUOTA " (since Linux 4.6)"
 514 .\" commit 8b37524962b9c54423374717786198f5c0820a28
 515 This operation is the same as
 516 .BR Q_XGETQUOTA ,
 517 but it returns (in the
 518 .I fs_disk_quota
 519 structure pointed by
 520 .IR addr )
 521 quota information for the next ID greater than or equal to
 522 .IR id
 523 that has a quota set.
 524 Note that since
 525 .I fs_disk_quota
 526 already has
 527 .I q_id
 528 field, no separate structure type is needed (in contrast with
 529 .B Q_GETQUOTA
 530 and
 531 .B Q_GETNEXTQUOTA
 532 operations)
 533 .TP
 534 .B Q_XSETQLIM
 535 Set disk quota limits for user
 536 .IR id .
 537 The
 538 .I addr
 539 argument is a pointer to an
 540 .I fs_disk_quota
 541 structure.
 542 This operation requires privilege
 543 .RB ( CAP_SYS_ADMIN ).
 544 .TP
 545 .B Q_XGETQSTAT
 546 Returns XFS filesystem-specific quota information in the
 547 .I fs_quota_stat
 548 structure pointed by
 549 .IR addr .
 550 This is useful for finding out how much space is used to store quota
 551 information, and also to get the quota on/off status of a given local XFS
 552 filesystem.
 553 The
 554 .I fs_quota_stat
 555 structure itself is defined as follows:
 556 .IP
 557 .in +4n
 558 .EX
 559 #define FS_QSTAT_VERSION 1  /* fs_quota_stat.qs_version */
 560
 561 struct fs_qfilestat {
 562     uint64_t qfs_ino;       /* Inode number */
 563     uint64_t qfs_nblks;     /* Number of BBs
 564                                512-byte-blocks */
 565     uint32_t qfs_nextents;  /* Number of extents */
 566 };
 567
 568 struct fs_quota_stat {
 569     int8_t   qs_version; /* Version number for
 570                             future changes */
 571     uint16_t qs_flags; /* XFS_QUOTA_{U,P,G}DQ_{ACCT,ENFD} */
 572     int8_t   qs_pad;   /* Unused */
 573     struct fs_qfilestat qs_uquota;  /* User quota storage
 574                                        information */
 575     struct fs_qfilestat qs_gquota;  /* Group quota storage
 576                                        information */
 577     uint32_t qs_incoredqs;   /* Number of dquots in core */
 578     int32_t  qs_btimelimit;  /* Limit for blocks timer */
 579     int32_t  qs_itimelimit;  /* Limit for inodes timer */
 580     int32_t  qs_rtbtimelimit;/* Limit for RT
 581                                 blocks timer */
 582     uint16_t qs_bwarnlimit;  /* Limit for # of warnings */
 583     uint16_t qs_iwarnlimit;  /* Limit for # of warnings */
 584 };
 585 .EE
 586 .in
 587 .IP
 588 The
 589 .I id
 590 argument is ignored.
 591 .TP
 592 .B Q_XGETQSTATV
 593 Returns XFS filesystem-specific quota information in the
 594 .I fs_quota_statv
 595 pointed to by
 596 .IR addr .
 597 This version of the operation uses a structure with proper versioning support,
 598 along with appropriate layout (all fields are naturally aligned) and
 599 padding to avoiding special compat handling;
 600 it also provides the ability to get statistics regarding
 601 the project quota file.
 602 The
 603 .I fs_quota_statv
 604 structure itself is defined as follows:
 605 .IP
 606 .in +4n
 607 .EX
 608 #define FS_QSTATV_VERSION1 1 /* fs_quota_statv.qs_version */
 609
 610 struct fs_qfilestatv {
 611     uint64_t qfs_ino;       /* Inode number */
 612     uint64_t qfs_nblks;     /* Number of BBs
 613                                512-byte-blocks */
 614     uint32_t qfs_nextents;  /* Number of extents */
 615     uint32_t qfs_pad;       /* Pad for 8-byte alignment */
 616 };
 617
 618 struct fs_quota_statv {
 619     int8_t   qs_version;    /* Version for future
 620                                changes */
 621     uint8_t  qs_pad1;       /* Pad for 16-bit alignment */
 622     uint16_t qs_flags;      /* XFS_QUOTA_.* flags */
 623     uint32_t qs_incoredqs;  /* Number of dquots incore */
 624     struct fs_qfilestatv qs_uquota;  /* User quota
 625                                         information */
 626     struct fs_qfilestatv qs_gquota;  /* Group quota
 627                                         information */
 628     struct fs_qfilestatv qs_pquota;  /* Project quota
 629                                         information */
 630     int32_t  qs_btimelimit;   /* Limit for blocks timer */
 631     int32_t  qs_itimelimit;   /* Limit for inodes timer */
 632     int32_t  qs_rtbtimelimit; /* Limit for RT blocks
 633                                  timer */
 634     uint16_t qs_bwarnlimit;   /* Limit for # of warnings */
 635     uint16_t qs_iwarnlimit;   /* Limit for # of warnings */
 636     uint64_t qs_pad2[8];      /* For future proofing */
 637 };
 638 .EE
 639 .in
 640 .IP
 641 The
 642 .I qs_version
 643 field of the structure should be filled with the version of the structure
 644 supported by the callee (for now, only
 645 .I FS_QSTAT_VERSION1
 646 is supported).
 647 The kernel will fill the structure in accordance with
 648 version provided.
 649 The
 650 .I id
 651 argument is ignored.
 652 .TP
 653 .B Q_XQUOTARM " (since Linux 3.16)"
 654 .\" 9da93f9b7cdf8ab28da6b364cdc1fafc8670b4dc
 655 Free the disk space taken by disk quotas.
 656 The
 657 .I addr
 658 argument should be a pointer to an
 659 .I "unsigned int"
 660 value containing flags (the same as in
 661 .I d_flags
 662 field of
 663 .I fs_disk_quota
 664 structure)
 665 which identify what types of quota
 666 should be removed.
 667 (Note that the quota type passed in the
 668 .I cmd
 669 argument is ignored, but should remain valid in order to pass preliminary
 670 quotactl syscall handler checks.)
 671 .IP
 672 Quotas must have already been turned off.
 673 The
 674 .I id
 675 argument is ignored.
 676 .TP
 677 .BR Q_XQUOTASYNC " (since Linux 2.6.15; no-op since Linux 3.4)"
 678 .\" Added in commit ee34807a65aa0c5911dc27682863afca780a003e
 679 This operation was an XFS quota equivalent to
 680 .BR Q_SYNC ,
 681 but it is no-op since Linux 3.4,
 682 .\" 4b217ed9e30f94b6e8e5e262020ef0ceab6113af
 683 as
 684 .BR sync (1)
 685 writes quota information to disk now
 686 (in addition to the other filesystem metadata that it writes out).
 687 The
 688 .IR special ", " id " and " addr
 689 arguments are ignored.
 690 .SH RETURN VALUE
 691 .PP
 692 On success,
 693 .BR quotactl ()
 694 returns 0; on error \-1
 695 is returned, and
 696 .I errno
 697 is set to indicate the error.
 698 .SH ERRORS
 699 .TP
 700 .B EACCES
 701 .I cmd
 702 is
 703 .BR Q_QUOTAON ,
 704 and the quota file pointed to by
 705 .I addr
 706 exists, but is not a regular file or
 707 is not on the filesystem pointed to by
 708 .IR special .
 709 .TP
 710 .B EBUSY
 711 .I cmd
 712 is
 713 .BR Q_QUOTAON ,
 714 but another
 715 .B Q_QUOTAON
 716 had already been performed.
 717 .TP
 718 .B EFAULT
 719 .I addr
 720 or
 721 .I special
 722 is invalid.
 723 .TP
 724 .B EINVAL
 725 .I cmd
 726 or
 727 .I type
 728 is invalid.
 729 .TP
 730 .B EINVAL
 731 .I cmd
 732 is
 733 .BR Q_QUOTAON ,
 734 but the specified quota file is corrupted.
 735 .TP
 736 .BR EINVAL " (since Linux 5.5)"
 737 .\" 3dd4d40b420846dd35869ccc8f8627feef2cff32
 738 .I cmd
 739 is
 740 .BR Q_XQUOTARM ,
 741 but
 742 .I addr
 743 does not point to valid quota types.
 744 .TP
 745 .B ENOENT
 746 The file specified by
 747 .I special
 748 or
 749 .I addr
 750 does not exist.
 751 .TP
 752 .B ENOSYS
 753 The kernel has not been compiled with the
 754 .B CONFIG_QUOTA
 755 option.
 756 .TP
 757 .B ENOTBLK
 758 .I special
 759 is not a block device.
 760 .TP
 761 .B EPERM
 762 The caller lacked the required privilege
 763 .RB ( CAP_SYS_ADMIN )
 764 for the specified operation.
 765 .TP
 766 .B ERANGE
 767 .I cmd
 768 is
 769 .BR Q_SETQUOTA ,
 770 but the specified limits are out of the range allowed by the quota format.
 771 .TP
 772 .B ESRCH
 773 No disk quota is found for the indicated user.
 774 Quotas have not been turned on for this filesystem.
 775 .TP
 776 .B ESRCH
 777 .I cmd
 778 is
 779 .BR Q_QUOTAON ,
 780 but the specified quota format was not found.
 781 .TP
 782 .B ESRCH
 783 .I cmd
 784 is
 785 .B Q_GETNEXTQUOTA
 786 or
 787 .BR Q_XGETNEXTQUOTA ,
 788 but there is no ID greater than or equal to
 789 .IR id
 790 that has an active quota.
 791 .SH NOTES
 792 Instead of
 793 .I <xfs/xqm.h>
 794 one can use
 795 .IR <linux/dqblk_xfs.h> ,
 796 taking into account that there are several naming discrepancies:
 797 .IP \(bu 3
 798 Quota enabling flags (of format
 799 .BR XFS_QUOTA_[UGP]DQ_{ACCT,ENFD} )
 800 are defined without a leading "X", as
 801 .BR FS_QUOTA_[UGP]DQ_{ACCT,ENFD} .
 802 .IP \(bu
 803 The same is true for
 804 .B XFS_{USER,GROUP,PROJ}_QUOTA
 805 quota type flags, which are defined as
 806 .BR FS_{USER,GROUP,PROJ}_QUOTA .
 807 .IP \(bu
 808 The
 809 .I dqblk_xfs.h
 810 header file defines its own
 811 .BR XQM_USRQUOTA ,
 812 .BR XQM_GRPQUOTA ,
 813 and
 814 .B XQM_PRJQUOTA
 815 constants for the available quota types, but their values are the same as for
 816 constants without the
 817 .B XQM_
 818 prefix.
 819 .SH SEE ALSO
 820 .BR quota (1),
 821 .BR getrlimit (2),
 822 .BR quotacheck (8),
 823 .BR quotaon (8)