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author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-25 13:48:29 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-25 13:48:29 -0700 |
commit | 74eb94b218d087798a52c0b4f1379b635287a4b8 (patch) | |
tree | 4e467c3014c2b1169f6f71d88cf5d1598f3ce28e /Documentation/filesystems/nfs/idmapper.txt | |
parent | 7b6181e06841f5ad15c4ff708b967b4db65a64de (diff) | |
parent | 9a84d38031c258a17bb39beed1e500eadee67407 (diff) | |
download | linux-stable-74eb94b218d087798a52c0b4f1379b635287a4b8.tar.gz linux-stable-74eb94b218d087798a52c0b4f1379b635287a4b8.tar.bz2 linux-stable-74eb94b218d087798a52c0b4f1379b635287a4b8.zip |
Merge branch 'nfs-for-2.6.37' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6
* 'nfs-for-2.6.37' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6: (67 commits)
SUNRPC: Cleanup duplicate assignment in rpcauth_refreshcred
nfs: fix unchecked value
Ask for time_delta during fsinfo probe
Revalidate caches on lock
SUNRPC: After calling xprt_release(), we must restart from call_reserve
NFSv4: Fix up the 'dircount' hint in encode_readdir
NFSv4: Clean up nfs4_decode_dirent
NFSv4: nfs4_decode_dirent must clear entry->fattr->valid
NFSv4: Fix a regression in decode_getfattr
NFSv4: Fix up decode_attr_filehandle() to handle the case of empty fh pointer
NFS: Ensure we check all allocation return values in new readdir code
NFS: Readdir plus in v4
NFS: introduce generic decode_getattr function
NFS: check xdr_decode for errors
NFS: nfs_readdir_filler catch all errors
NFS: readdir with vmapped pages
NFS: remove page size checking code
NFS: decode_dirent should use an xdr_stream
SUNRPC: Add a helper function xdr_inline_peek
NFS: remove readdir plus limit
...
Diffstat (limited to 'Documentation/filesystems/nfs/idmapper.txt')
-rw-r--r-- | Documentation/filesystems/nfs/idmapper.txt | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/Documentation/filesystems/nfs/idmapper.txt b/Documentation/filesystems/nfs/idmapper.txt new file mode 100644 index 000000000000..c3852041a21f --- /dev/null +++ b/Documentation/filesystems/nfs/idmapper.txt @@ -0,0 +1,67 @@ + +========= +ID Mapper +========= +Id mapper is used by NFS to translate user and group ids into names, and to +translate user and group names into ids. Part of this translation involves +performing an upcall to userspace to request the information. Id mapper will +user request-key to perform this upcall and cache the result. The program +/usr/sbin/nfs.upcall should be called by request-key, and will perform the +translation and initialize a key with the resulting information. + + NFS_USE_NEW_IDMAPPER must be selected when configuring the kernel to use this + feature. + +=========== +Configuring +=========== +The file /etc/request-key.conf will need to be modified so /sbin/request-key can +direct the upcall. The following line should be added: + +#OP TYPE DESCRIPTION CALLOUT INFO PROGRAM ARG1 ARG2 ARG3 ... +#====== ======= =============== =============== =============================== +create id_resolver * * /usr/sbin/nfs.upcall %k %d 600 + +This will direct all id_resolver requests to the program /usr/sbin/nfs.upcall. +The last parameter, 600, defines how many seconds into the future the key will +expire. This parameter is optional for /usr/sbin/nfs.upcall. When the timeout +is not specified, nfs.upcall will default to 600 seconds. + +id mapper uses for key descriptions: + uid: Find the UID for the given user + gid: Find the GID for the given group + user: Find the user name for the given UID + group: Find the group name for the given GID + +You can handle any of these individually, rather than using the generic upcall +program. If you would like to use your own program for a uid lookup then you +would edit your request-key.conf so it look similar to this: + +#OP TYPE DESCRIPTION CALLOUT INFO PROGRAM ARG1 ARG2 ARG3 ... +#====== ======= =============== =============== =============================== +create id_resolver uid:* * /some/other/program %k %d 600 +create id_resolver * * /usr/sbin/nfs.upcall %k %d 600 + +Notice that the new line was added above the line for the generic program. +request-key will find the first matching line and corresponding program. In +this case, /some/other/program will handle all uid lookups and +/usr/sbin/nfs.upcall will handle gid, user, and group lookups. + +See <file:Documentation/keys-request-keys.txt> for more information about the +request-key function. + + +========== +nfs.upcall +========== +nfs.upcall is designed to be called by request-key, and should not be run "by +hand". This program takes two arguments, a serialized key and a key +description. The serialized key is first converted into a key_serial_t, and +then passed as an argument to keyctl_instantiate (both are part of keyutils.h). + +The actual lookups are performed by functions found in nfsidmap.h. nfs.upcall +determines the correct function to call by looking at the first part of the +description string. For example, a uid lookup description will appear as +"uid:user@domain". + +nfs.upcall will return 0 if the key was instantiated, and non-zero otherwise. |