манипулировать дисковыми квотами (manipulate disk quotas)
Описание (Description)
The quota system can be used to set per-user, per-group, and per-
project 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 grace period
duration (one week by default) at a time; after this, the soft
limit counts as a hard limit.
The quotactl() call manipulates disk quotas. The cmd argument
indicates a command to be applied to the user or group ID
specified in id. To initialize the cmd argument, use the
QCMD(subcmd, type) macro. The type value is either USRQUOTA, for
user quotas, GRPQUOTA, for group quotas, or (since Linux 4.1)
PRJQUOTA, for project quotas. The subcmd value is described
below.
The 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 addr argument is the address of an optional, command-
specific, data structure that is copied in or out of the system.
The interpretation of addr is given with each operation below.
The subcmd value is one of the following operations:
Q_QUOTAON
Turn on quotas for a filesystem. The id argument is the
identification number of the quota format to be used.
Currently, there are three supported quota formats:
QFMT_VFS_OLD
The original quota format.
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.
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.
The 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 quotacheck(8)
program
Quota information can be also stored in hidden system
inodes for ext4, XFS, and other filesystems if the
filesystem is configured so. In this case, there are no
visible quota files and there is no need to use
quotacheck(8). Quota information is always kept
consistent by the filesystem and the Q_QUOTAON operation
serves only to enable enforcement of quota limits. The
presence of hidden system inodes with quota information is
indicated by the DQF_SYS_FILE flag in the dqi_flags field
returned by the Q_GETINFO operation.
This operation requires privilege (CAP_SYS_ADMIN).
Q_QUOTAOFF
Turn off quotas for a filesystem. The addr and id
arguments are ignored. This operation requires privilege
(CAP_SYS_ADMIN).
Q_GETQUOTA
Get disk quota limits and current usage for user or group
id. The addr argument is a pointer to a dqblk structure
defined in <sys/quota.h> as follows:
/* 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 occupied space
(in bytes) */
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)
The dqb_valid field is a bit mask that is set to indicate
the entries in the dqblk structure that are valid.
Currently, the kernel fills in all entries of the dqblk
structure and marks them as valid in the dqb_valid field.
Unprivileged users may retrieve only their own quotas; a
privileged user (CAP_SYS_ADMIN) can retrieve the quotas of
any user.
Q_GETNEXTQUOTA (since Linux 4.6)
This operation is the same as Q_GETQUOTA, but it returns
quota information for the next ID greater than or equal to
id that has a quota set.
The addr argument is a pointer to a nextdqblk structure
whose fields are as for the dqblk, except for the addition
of a dqb_id field that is used to return the ID for which
quota information is being returned:
struct nextdqblk {
uint64_t dqb_bhardlimit;
uint64_t dqb_bsoftlimit;
uint64_t dqb_curspace;
uint64_t dqb_ihardlimit;
uint64_t dqb_isoftlimit;
uint64_t dqb_curinodes;
uint64_t dqb_btime;
uint64_t dqb_itime;
uint32_t dqb_valid;
uint32_t dqb_id;
};
Q_SETQUOTA
Set quota information for user or group id, using the
information supplied in the dqblk structure pointed to by
addr. The dqb_valid field of the dqblk structure
indicates which entries in the structure have been set by
the caller. This operation supersedes the Q_SETQLIM and
Q_SETUSE operations in the previous quota interfaces.
This operation requires privilege (CAP_SYS_ADMIN).
Q_GETINFO (since Linux 2.4.22)
Get information (like grace times) about quotafile. The
addr argument should be a pointer to a dqinfo structure.
This structure is defined in <sys/quota.h> as follows:
/* 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 DQF_ROOT_SQUASH (1 << 0) /* Root squash enabled */
/* Before Linux v4.0, this had been defined
privately as V1_DQF_RSQUASH */
/* Quota format QFMT_VFS_V0 / QFMT_VFS_V1 */
#define DQF_SYS_FILE (1 << 16) /* Quota stored in
a system file */
/* 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)
The dqi_valid field in the dqinfo structure indicates the
entries in the structure that are valid. Currently, the
kernel fills in all entries of the dqinfo structure and
marks them all as valid in the dqi_valid field. The id
argument is ignored.
Q_SETINFO (since Linux 2.4.22)
Set information about quotafile. The addr argument should
be a pointer to a dqinfo structure. The dqi_valid field
of the dqinfo structure indicates the entries in the
structure that have been set by the caller. This
operation supersedes the Q_SETGRACE and Q_SETFLAGS
operations in the previous quota interfaces. The id
argument is ignored. This operation requires privilege
(CAP_SYS_ADMIN).
Q_GETFMT (since Linux 2.4.22)
Get quota format used on the specified filesystem. The
addr argument should be a pointer to a 4-byte buffer where
the format number will be stored.
Q_SYNC Update the on-disk copy of quota usages for a filesystem.
If special is NULL, then all filesystems with active
quotas are sync'ed. The addr and id arguments are
ignored.
Q_GETSTATS (supported up to Linux 2.4.21)
Get statistics and other generic information about the
quota subsystem. The addr argument should be a pointer to
a dqstats structure in which data should be stored. This
structure is defined in <sys/quota.h>. The special and id
arguments are ignored.
This operation is obsolete and was removed in Linux
2.4.22. Files in /proc/sys/fs/quota/ carry the
information instead.
For XFS filesystems making use of the XFS Quota Manager (XQM),
the above operations are bypassed and the following operations
are used:
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 addr to be a pointer
to an unsigned int that contains a bitwise combination of
the following flags (defined in <xfs/xqm.h>):
XFS_QUOTA_UDQ_ACCT /* User quota accounting */
XFS_QUOTA_UDQ_ENFD /* User quota limits enforcement */
XFS_QUOTA_GDQ_ACCT /* Group quota accounting */
XFS_QUOTA_GDQ_ENFD /* Group quota limits enforcement */
XFS_QUOTA_PDQ_ACCT /* Project quota accounting */
XFS_QUOTA_PDQ_ENFD /* Project quota limits enforcement */
This operation requires privilege (CAP_SYS_ADMIN). The id
argument is ignored.
Q_XQUOTAOFF
Turn off quotas for an XFS filesystem. As with Q_QUOTAON,
XFS filesystems expect a pointer to an unsigned int that
specifies whether quota accounting and/or limit
enforcement need to be turned off (using the same flags as
for Q_XQUOTAON operation). This operation requires
privilege (CAP_SYS_ADMIN). The id argument is ignored.
Q_XGETQUOTA
Get disk quota limits and current usage for user id. The
addr argument is a pointer to an fs_disk_quota structure,
which is defined in <xfs/xqm.h> as follows:
/* All the blk units are in BBs (Basic Blocks) of
512 bytes. */
#define FS_DQUOT_VERSION 1 /* fs_disk_quota.d_version */
#define XFS_USER_QUOTA (1<<0) /* User quota type */
#define XFS_PROJ_QUOTA (1<<1) /* Project quota type */
#define XFS_GROUP_QUOTA (1<<2) /* Group quota type */
struct fs_disk_quota {
int8_t d_version; /* Version of this structure */
int8_t d_flags; /* XFS_{USER,PROJ,GROUP}_QUOTA */
uint16_t d_fieldmask; /* Field specifier */
uint32_t d_id; /* User, project, or group ID */
uint64_t d_blk_hardlimit; /* Absolute limit on
disk blocks */
uint64_t d_blk_softlimit; /* Preferred limit on
disk blocks */
uint64_t d_ino_hardlimit; /* Maximum # allocated
inodes */
uint64_t d_ino_softlimit; /* Preferred inode limit */
uint64_t d_bcount; /* # disk blocks owned by
the user */
uint64_t d_icount; /* # inodes owned by the user */
int32_t d_itimer; /* Zero if within inode limits */
/* If not, we refuse service */
int32_t d_btimer; /* Similar to above; for
disk blocks */
uint16_t d_iwarns; /* # warnings issued with
respect to # of inodes */
uint16_t d_bwarns; /* # warnings issued with
respect to disk blocks */
int32_t d_padding2; /* Padding - for future use */
uint64_t d_rtb_hardlimit; /* Absolute limit on realtime
(RT) disk blocks */
uint64_t d_rtb_softlimit; /* Preferred limit on RT
disk blocks */
uint64_t d_rtbcount; /* # realtime blocks owned */
int32_t d_rtbtimer; /* Similar to above; for RT
disk blocks */
uint16_t d_rtbwarns; /* # warnings issued with
respect to RT disk blocks */
int16_t d_padding3; /* Padding - for future use */
char d_padding4[8]; /* Yet more padding */
};
Unprivileged users may retrieve only their own quotas; a
privileged user (CAP_SYS_ADMIN) may retrieve the quotas of
any user.
Q_XGETNEXTQUOTA (since Linux 4.6)
This operation is the same as Q_XGETQUOTA, but it returns
(in the fs_disk_quota structure pointed by addr) quota
information for the next ID greater than or equal to id
that has a quota set. Note that since fs_disk_quota
already has q_id field, no separate structure type is
needed (in contrast with Q_GETQUOTA and Q_GETNEXTQUOTA
operations)
Q_XSETQLIM
Set disk quota limits for user id. The addr argument is a
pointer to an fs_disk_quota structure. This operation
requires privilege (CAP_SYS_ADMIN).
Q_XGETQSTAT
Returns XFS filesystem-specific quota information in the
fs_quota_stat structure pointed by addr. This is useful
for finding out how much space is used to store quota
information, and also to get the quota on/off status of a
given local XFS filesystem. The fs_quota_stat structure
itself is defined as follows:
#define FS_QSTAT_VERSION 1 /* fs_quota_stat.qs_version */
struct fs_qfilestat {
uint64_t qfs_ino; /* Inode number */
uint64_t qfs_nblks; /* Number of BBs
512-byte-blocks */
uint32_t qfs_nextents; /* Number of extents */
};
struct fs_quota_stat {
int8_t qs_version; /* Version number for
future changes */
uint16_t qs_flags; /* XFS_QUOTA_{U,P,G}DQ_{ACCT,ENFD} */
int8_t qs_pad; /* Unused */
struct fs_qfilestat qs_uquota; /* User quota storage
information */
struct fs_qfilestat qs_gquota; /* Group quota storage
information */
uint32_t qs_incoredqs; /* Number of dquots in core */
int32_t qs_btimelimit; /* Limit for blocks timer */
int32_t qs_itimelimit; /* Limit for inodes timer */
int32_t qs_rtbtimelimit;/* Limit for RT
blocks timer */
uint16_t qs_bwarnlimit; /* Limit for # of warnings */
uint16_t qs_iwarnlimit; /* Limit for # of warnings */
};
The id argument is ignored.
Q_XGETQSTATV
Returns XFS filesystem-specific quota information in the
fs_quota_statv pointed to by addr. This version of the
operation uses a structure with proper versioning support,
along with appropriate layout (all fields are naturally
aligned) and padding to avoiding special compat handling;
it also provides the ability to get statistics regarding
the project quota file. The fs_quota_statv structure
itself is defined as follows:
#define FS_QSTATV_VERSION1 1 /* fs_quota_statv.qs_version */
struct fs_qfilestatv {
uint64_t qfs_ino; /* Inode number */
uint64_t qfs_nblks; /* Number of BBs
512-byte-blocks */
uint32_t qfs_nextents; /* Number of extents */
uint32_t qfs_pad; /* Pad for 8-byte alignment */
};
struct fs_quota_statv {
int8_t qs_version; /* Version for future
changes */
uint8_t qs_pad1; /* Pad for 16-bit alignment */
uint16_t qs_flags; /* XFS_QUOTA_.* flags */
uint32_t qs_incoredqs; /* Number of dquots incore */
struct fs_qfilestatv qs_uquota; /* User quota
information */
struct fs_qfilestatv qs_gquota; /* Group quota
information */
struct fs_qfilestatv qs_pquota; /* Project quota
information */
int32_t qs_btimelimit; /* Limit for blocks timer */
int32_t qs_itimelimit; /* Limit for inodes timer */
int32_t qs_rtbtimelimit; /* Limit for RT blocks
timer */
uint16_t qs_bwarnlimit; /* Limit for # of warnings */
uint16_t qs_iwarnlimit; /* Limit for # of warnings */
uint64_t qs_pad2[8]; /* For future proofing */
};
The qs_version field of the structure should be filled
with the version of the structure supported by the callee
(for now, only FS_QSTAT_VERSION1 is supported). The
kernel will fill the structure in accordance with version
provided. The id argument is ignored.
Q_XQUOTARM (since Linux 3.16)
Free the disk space taken by disk quotas. The addr
argument should be a pointer to an unsigned int value
containing flags (the same as in d_flags field of
fs_disk_quota structure) which identify what types of
quota should be removed. (Note that the quota type passed
in the cmd argument is ignored, but should remain valid in
order to pass preliminary quotactl syscall handler
checks.)
Quotas must have already been turned off. The id argument
is ignored.
Q_XQUOTASYNC (since Linux 2.6.15; no-op since Linux 3.4)
This operation was an XFS quota equivalent to Q_SYNC, but
it is no-op since Linux 3.4, as sync(1) writes quota
information to disk now (in addition to the other
filesystem metadata that it writes out). The special, id
and addr arguments are ignored.
