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Diffstat (limited to 'Documentation/filesystems/quota.txt')
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diff --git a/Documentation/filesystems/quota.txt b/Documentation/filesystems/quota.txt deleted file mode 100644 index 32874b06ebe9..000000000000 --- a/Documentation/filesystems/quota.txt +++ /dev/null @@ -1,68 +0,0 @@ - -Quota subsystem -=============== - -Quota subsystem allows system administrator to set limits on used space and -number of used inodes (inode is a filesystem structure which is associated with -each file or directory) for users and/or groups. For both used space and number -of used inodes there are actually two limits. The first one is called softlimit -and the second one hardlimit. A user can never exceed a hardlimit for any -resource (unless he has CAP_SYS_RESOURCE capability). User is allowed to exceed -softlimit but only for limited period of time. This period is called "grace -period" or "grace time". When grace time is over, user is not able to allocate -more space/inodes until he frees enough of them to get below softlimit. - -Quota limits (and amount of grace time) are set independently for each -filesystem. - -For more details about quota design, see the documentation in quota-tools package -(http://sourceforge.net/projects/linuxquota). - -Quota netlink interface -======================= -When user exceeds a softlimit, runs out of grace time or reaches hardlimit, -quota subsystem traditionally printed a message to the controlling terminal of -the process which caused the excess. This method has the disadvantage that -when user is using a graphical desktop he usually cannot see the message. -Thus quota netlink interface has been designed to pass information about -the above events to userspace. There they can be captured by an application -and processed accordingly. - -The interface uses generic netlink framework (see -http://lwn.net/Articles/208755/ and http://people.suug.ch/~tgr/libnl/ for more -details about this layer). The name of the quota generic netlink interface -is "VFS_DQUOT". Definitions of constants below are in <linux/quota.h>. -Since the quota netlink protocol is not namespace aware, quota netlink messages -are sent only in initial network namespace. - -Currently, the interface supports only one message type QUOTA_NL_C_WARNING. -This command is used to send a notification about any of the above mentioned -events. Each message has six attributes. These are (type of the argument is -in parentheses): - QUOTA_NL_A_QTYPE (u32) - - type of quota being exceeded (one of USRQUOTA, GRPQUOTA) - QUOTA_NL_A_EXCESS_ID (u64) - - UID/GID (depends on quota type) of user / group whose limit - is being exceeded. - QUOTA_NL_A_CAUSED_ID (u64) - - UID of a user who caused the event - QUOTA_NL_A_WARNING (u32) - - what kind of limit is exceeded: - QUOTA_NL_IHARDWARN - inode hardlimit - QUOTA_NL_ISOFTLONGWARN - inode softlimit is exceeded longer - than given grace period - QUOTA_NL_ISOFTWARN - inode softlimit - QUOTA_NL_BHARDWARN - space (block) hardlimit - QUOTA_NL_BSOFTLONGWARN - space (block) softlimit is exceeded - longer than given grace period. - QUOTA_NL_BSOFTWARN - space (block) softlimit - - four warnings are also defined for the event when user stops - exceeding some limit: - QUOTA_NL_IHARDBELOW - inode hardlimit - QUOTA_NL_ISOFTBELOW - inode softlimit - QUOTA_NL_BHARDBELOW - space (block) hardlimit - QUOTA_NL_BSOFTBELOW - space (block) softlimit - QUOTA_NL_A_DEV_MAJOR (u32) - - major number of a device with the affected filesystem - QUOTA_NL_A_DEV_MINOR (u32) - - minor number of a device with the affected filesystem |