long quotactl(int cmd, char *special, qid_t id, caddr_t addr)
描述
The%uA0quotactl()ꃊll manipulates disk quotas.%uA0cmd%uA0indicates a command to be applied toUID%uA0id%uA0or%uA0GID%uA0id. To set the type of quota use the%uA0QCMD(cmd, type)%uA0macro.%uA0special%uA0is a pointer to a null-terminated string containing the path name of the block special device for the filesystem being manipulated.%uA0addr%uA0is the address of an optional, command specific, data structure which is copied in or out of the system. The interpretation of%uA0addris given with each command below.
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描述
Q_QUOTAON
Turn on quotas for a filesystem.%uA0id%uA0is the identification number of the quota format to be used. Format numbers are defined in the header file of appropriate format. Currently there are two supported quota formats whose numbers are defined by constants%uA0QFMT_VFS_OLD%uA0(original quota format) andQFMT_VFS_V0%uA0(new VFS v0 quota format).%uA0addr%uA0points to the path name of file containing the quotas for the filesystem. The quota file must exist it is normally created with thequotacheck(8) program. This call is restricted to the super-user.
Q_QUOTAOFF
Turn off quotas for a filesystem.%uA0addr%uA0and%uA0id%uA0are ignored. This call is restricted to the super-user.
Q_GETQUOTA
Get disk quota limits and current usage for user or group%uA0id.%uA0addris a pointer to an%uA0if_dqblk%uA0structure (defined in<sys/quota.h>). The field%uA0dqb_validꃞfines the entries in the structure which are set correctly. On%uA0Q_GETQUOTAꃊll all entries are valid. Only the super-user may get the quotas of a user other than himself.
Q_SETQUOTA
Set current quota information for user or group%uA0id.%uA0addr%uA0is a pointer to an%uA0if_dqblk%uA0structure (defined in%uA0<sys/quota.h>). The field%uA0dqb_validꃞfines which entries in the quota structure are valid and should be set. The constants for%uA0dqb_valid%uA0field are defined in the%uA0<sys/quota.h>%uA0header file. This call obsoletes calls%uA0Q_SETQLIM%uA0and%uA0Q_SETUSE%uA0in the previous quota interfaces. This call is restricted to the super-user.
Q_GETINFO
Get information (like grace times) about quotafile.%uA0addr%uA0should be a pointer to an%uA0if_dqinfo%uA0structure (defined in<sys/quota.h>). The%uA0dqi_valid%uA0field in the structure defines entries in it which are valid. On%uA0Q_GETINFOꃊll all entries are valid. Parameter%uA0id%uA0is ignored.
Q_SETINFO
Set information about quotafile.%uA0addr%uA0should be a pointer toif_dqinfo%uA0structure (defined in%uA0<sys/quota.h>). The field%uA0dqi_validdefines which entries in the quota info structure are valid and should be set. The constants for%uA0dqi_valid%uA0field are defined in the<sys/quota.h>%uA0header file. This call obsoletes callsQ_SETGRACE%uA0and%uA0Q_SETFLAGS%uA0in the previous quota interfaces. Parameter%uA0id%uA0is ignored. This operation is restricted to super-user.
Q_GETFMT
Get quota format used on the specified filesystem.%uA0addr%uA0should be a pointer to a memory (4 bytes) where the format number will be stored.
Q_SYNC
Update the on-disk copy of quota usages for a filesystem. Ifspecial%uA0is null then all filesystems with active quotas are sync’ed.addr%uA0and%uA0id%uA0are ignored.
Q_GETSTATS
Get statistics and other generic information about quota subsystem.%uA0addr%uA0should be a pointer to%uA0dqstats%uA0structure (defined in%uA0<sys/quota.h>) in which data should be stored.special%uA0and%uA0id%uA0are ignored.
For XFS filesystems making use of the XFS Quota Manager (XQM), the above commands are bypassed and the following commands are used:%uA0 Q_XQUOTAON
%uA0
Turn on quotas for an XFS filesystem. XFS provides the ability to turn on/off quota limit enforcement with quota accounting. Therefore, XFS expects the addr to be a pointer to an unsigned int that contains either the flags XFS_QUOTA_UDQ_ACCT and/or XFS_QUOTA_UDQ_ENFD (for user quota), or XFS_QUOTA_GDQ_ACCT and/or XFS_QUOTA_GDQ_ENFD (for group quota), as defined in%uA0<xfs/xqm.h>. This call is restricted to the superuser.
Q_XQUOTAOFF
Turn off quotas for an XFS filesystem. As in 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. This call is restricted to the superuser.
Q_XGETQUOTA
Get disk quota limits and current usage for user%uA0id.%uA0addr%uA0is a pointer to a%uA0fs_disk_quota%uA0structure (defined in%uA0<xfs/xqm.h>). Only the superuser may get the quotas of a user other than himself.
Q_XSETQLIM
Set disk quota limits for user%uA0id.%uA0addr%uA0is a pointer to afs_disk_quota%uA0structure (defined in%uA0<xfs/xqm.h>). This call is restricted to the superuser.
Q_XGETQSTAT
Returns a%uA0fs_quota_stat%uA0structure containing XFS filesystem specific quota information. This is useful in finding out how much space is spent to store quota information, and also to get quotaon/off status of a given local XFS filesystem.
Q_XQUOTARM
Free the disk space taken by disk quotas. Quotas must have already been turned off.
There is no command equivalent to%uA0Q_SYNC%uA0for XFS since%uA0sync(1) writes quota information to disk (in addition to the other filesystem metadata it writes out).
RETURN VALUES
quotactl()%uA0returns:
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描述
0
on success.
-1
on failure and sets%uA0errno%uA0to indicate the error.
错误
标签
描述
EFAULT
addr%uA0or%uA0special%uA0are invalid.
ENOSYS
The kernel has not been compiled with the%uA0QUOTA%uA0option.
EINVAL
%uA0
cmd%uA0or%uA0type%uA0is invalid.
ENOENT
The file specified by%uA0special%uA0or%uA0addr%uA0does not exist.
ENOTBLK
special%uA0is not a block device.
EPERM
The call is privileged and the caller was not the super-user.
ESRCH
No disc quota is found for the indicated user.
%uA0
Quotas have not been turned on for this filesystem.
If%uA0cmd%uA0is%uA0Q_QUOTAON,%uA0quotactl()%uA0may set errno to:
EACCES
The quota file pointed to by%uA0addr%uA0exists but is not a regular file.
%uA0
The quota file pointed to by%uA0addr%uA0exists but is not on the filesystem pointed to by%uA0special.
EINVAL
The quota file is corrupted.
ESRCH
Specified quota format was not found.
EBUSY
Q_QUOTAON%uA0attempted while another%uA0Q_QUOTAON%uA0has already taken place.