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diff --git a/Documentation/filesystems/afs.txt b/Documentation/filesystems/afs.txt deleted file mode 100644 index 8c6ea7b41048..000000000000 --- a/Documentation/filesystems/afs.txt +++ /dev/null @@ -1,258 +0,0 @@ - ==================== - kAFS: AFS FILESYSTEM - ==================== - -Contents: - - - Overview. - - Usage. - - Mountpoints. - - Dynamic root. - - Proc filesystem. - - The cell database. - - Security. - - The @sys substitution. - - -======== -OVERVIEW -======== - -This filesystem provides a fairly simple secure AFS filesystem driver. It is -under development and does not yet provide the full feature set. The features -it does support include: - - (*) Security (currently only AFS kaserver and KerberosIV tickets). - - (*) File reading and writing. - - (*) Automounting. - - (*) Local caching (via fscache). - -It does not yet support the following AFS features: - - (*) pioctl() system call. - - -=========== -COMPILATION -=========== - -The filesystem should be enabled by turning on the kernel configuration -options: - - CONFIG_AF_RXRPC - The RxRPC protocol transport - CONFIG_RXKAD - The RxRPC Kerberos security handler - CONFIG_AFS - The AFS filesystem - -Additionally, the following can be turned on to aid debugging: - - CONFIG_AF_RXRPC_DEBUG - Permit AF_RXRPC debugging to be enabled - CONFIG_AFS_DEBUG - Permit AFS debugging to be enabled - -They permit the debugging messages to be turned on dynamically by manipulating -the masks in the following files: - - /sys/module/af_rxrpc/parameters/debug - /sys/module/kafs/parameters/debug - - -===== -USAGE -===== - -When inserting the driver modules the root cell must be specified along with a -list of volume location server IP addresses: - - modprobe rxrpc - modprobe kafs rootcell=cambridge.redhat.com:172.16.18.73:172.16.18.91 - -The first module is the AF_RXRPC network protocol driver. This provides the -RxRPC remote operation protocol and may also be accessed from userspace. See: - - Documentation/networking/rxrpc.txt - -The second module is the kerberos RxRPC security driver, and the third module -is the actual filesystem driver for the AFS filesystem. - -Once the module has been loaded, more modules can be added by the following -procedure: - - echo add grand.central.org 18.9.48.14:128.2.203.61:130.237.48.87 >/proc/fs/afs/cells - -Where the parameters to the "add" command are the name of a cell and a list of -volume location servers within that cell, with the latter separated by colons. - -Filesystems can be mounted anywhere by commands similar to the following: - - mount -t afs "%cambridge.redhat.com:root.afs." /afs - mount -t afs "#cambridge.redhat.com:root.cell." /afs/cambridge - mount -t afs "#root.afs." /afs - mount -t afs "#root.cell." /afs/cambridge - -Where the initial character is either a hash or a percent symbol depending on -whether you definitely want a R/W volume (percent) or whether you'd prefer a -R/O volume, but are willing to use a R/W volume instead (hash). - -The name of the volume can be suffixes with ".backup" or ".readonly" to -specify connection to only volumes of those types. - -The name of the cell is optional, and if not given during a mount, then the -named volume will be looked up in the cell specified during modprobe. - -Additional cells can be added through /proc (see later section). - - -=========== -MOUNTPOINTS -=========== - -AFS has a concept of mountpoints. In AFS terms, these are specially formatted -symbolic links (of the same form as the "device name" passed to mount). kAFS -presents these to the user as directories that have a follow-link capability -(ie: symbolic link semantics). If anyone attempts to access them, they will -automatically cause the target volume to be mounted (if possible) on that site. - -Automatically mounted filesystems will be automatically unmounted approximately -twenty minutes after they were last used. Alternatively they can be unmounted -directly with the umount() system call. - -Manually unmounting an AFS volume will cause any idle submounts upon it to be -culled first. If all are culled, then the requested volume will also be -unmounted, otherwise error EBUSY will be returned. - -This can be used by the administrator to attempt to unmount the whole AFS tree -mounted on /afs in one go by doing: - - umount /afs - - -============ -DYNAMIC ROOT -============ - -A mount option is available to create a serverless mount that is only usable -for dynamic lookup. Creating such a mount can be done by, for example: - - mount -t afs none /afs -o dyn - -This creates a mount that just has an empty directory at the root. Attempting -to look up a name in this directory will cause a mountpoint to be created that -looks up a cell of the same name, for example: - - ls /afs/grand.central.org/ - - -=============== -PROC FILESYSTEM -=============== - -The AFS modules creates a "/proc/fs/afs/" directory and populates it: - - (*) A "cells" file that lists cells currently known to the afs module and - their usage counts: - - [root@andromeda ~]# cat /proc/fs/afs/cells - USE NAME - 3 cambridge.redhat.com - - (*) A directory per cell that contains files that list volume location - servers, volumes, and active servers known within that cell. - - [root@andromeda ~]# cat /proc/fs/afs/cambridge.redhat.com/servers - USE ADDR STATE - 4 172.16.18.91 0 - [root@andromeda ~]# cat /proc/fs/afs/cambridge.redhat.com/vlservers - ADDRESS - 172.16.18.91 - [root@andromeda ~]# cat /proc/fs/afs/cambridge.redhat.com/volumes - USE STT VLID[0] VLID[1] VLID[2] NAME - 1 Val 20000000 20000001 20000002 root.afs - - -================= -THE CELL DATABASE -================= - -The filesystem maintains an internal database of all the cells it knows and the -IP addresses of the volume location servers for those cells. The cell to which -the system belongs is added to the database when modprobe is performed by the -"rootcell=" argument or, if compiled in, using a "kafs.rootcell=" argument on -the kernel command line. - -Further cells can be added by commands similar to the following: - - echo add CELLNAME VLADDR[:VLADDR][:VLADDR]... >/proc/fs/afs/cells - echo add grand.central.org 18.9.48.14:128.2.203.61:130.237.48.87 >/proc/fs/afs/cells - -No other cell database operations are available at this time. - - -======== -SECURITY -======== - -Secure operations are initiated by acquiring a key using the klog program. A -very primitive klog program is available at: - - http://people.redhat.com/~dhowells/rxrpc/klog.c - -This should be compiled by: - - make klog LDLIBS="-lcrypto -lcrypt -lkrb4 -lkeyutils" - -And then run as: - - ./klog - -Assuming it's successful, this adds a key of type RxRPC, named for the service -and cell, eg: "afs@<cellname>". This can be viewed with the keyctl program or -by cat'ing /proc/keys: - - [root@andromeda ~]# keyctl show - Session Keyring - -3 --alswrv 0 0 keyring: _ses.3268 - 2 --alswrv 0 0 \_ keyring: _uid.0 - 111416553 --als--v 0 0 \_ rxrpc: afs@CAMBRIDGE.REDHAT.COM - -Currently the username, realm, password and proposed ticket lifetime are -compiled in to the program. - -It is not required to acquire a key before using AFS facilities, but if one is -not acquired then all operations will be governed by the anonymous user parts -of the ACLs. - -If a key is acquired, then all AFS operations, including mounts and automounts, -made by a possessor of that key will be secured with that key. - -If a file is opened with a particular key and then the file descriptor is -passed to a process that doesn't have that key (perhaps over an AF_UNIX -socket), then the operations on the file will be made with key that was used to -open the file. - - -===================== -THE @SYS SUBSTITUTION -===================== - -The list of up to 16 @sys substitutions for the current network namespace can -be configured by writing a list to /proc/fs/afs/sysname: - - [root@andromeda ~]# echo foo amd64_linux_26 >/proc/fs/afs/sysname - -or cleared entirely by writing an empty list: - - [root@andromeda ~]# echo >/proc/fs/afs/sysname - -The current list for current network namespace can be retrieved by: - - [root@andromeda ~]# cat /proc/fs/afs/sysname - foo - amd64_linux_26 - -When @sys is being substituted for, each element of the list is tried in the -order given. - -By default, the list will contain one item that conforms to the pattern -"<arch>_linux_26", amd64 being the name for x86_64. |