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-rw-r--r--Documentation/filesystems/nfs/idmapper.txt20
-rw-r--r--Documentation/filesystems/nfs/pnfs.txt54
2 files changed, 68 insertions, 6 deletions
diff --git a/Documentation/filesystems/nfs/idmapper.txt b/Documentation/filesystems/nfs/idmapper.txt
index 120fd3c..fe03d10 100644
--- a/Documentation/filesystems/nfs/idmapper.txt
+++ b/Documentation/filesystems/nfs/idmapper.txt
@@ -4,13 +4,21 @@ 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.idmap should be called by request-key, and will perform the
-translation and initialize a key with the resulting information.
+performing an upcall to userspace to request the information. There are two
+ways NFS could obtain this information: placing a call to /sbin/request-key
+or by placing a call to the rpc.idmap daemon.
+
+NFS will attempt to call /sbin/request-key first. If this succeeds, the
+result will be cached using the generic request-key cache. This call should
+only fail if /etc/request-key.conf is not configured for the id_resolver key
+type, see the "Configuring" section below if you wish to use the request-key
+method.
+
+If the call to /sbin/request-key fails (if /etc/request-key.conf is not
+configured with the id_resolver key type), then the idmapper will ask the
+legacy rpc.idmap daemon for the id mapping. This result will be stored
+in a custom NFS idmap cache.
- NFS_USE_NEW_IDMAPPER must be selected when configuring the kernel to use this
- feature.
===========
Configuring
diff --git a/Documentation/filesystems/nfs/pnfs.txt b/Documentation/filesystems/nfs/pnfs.txt
index 983e14a..c7919c6 100644
--- a/Documentation/filesystems/nfs/pnfs.txt
+++ b/Documentation/filesystems/nfs/pnfs.txt
@@ -53,3 +53,57 @@ lseg maintains an extra reference corresponding to the NFS_LSEG_VALID
bit which holds it in the pnfs_layout_hdr's list. When the final lseg
is removed from the pnfs_layout_hdr's list, the NFS_LAYOUT_DESTROYED
bit is set, preventing any new lsegs from being added.
+
+layout drivers
+--------------
+
+PNFS utilizes what is called layout drivers. The STD defines 3 basic
+layout types: "files" "objects" and "blocks". For each of these types
+there is a layout-driver with a common function-vectors table which
+are called by the nfs-client pnfs-core to implement the different layout
+types.
+
+Files-layout-driver code is in: fs/nfs/nfs4filelayout.c && nfs4filelayoutdev.c
+Objects-layout-deriver code is in: fs/nfs/objlayout/.. directory
+Blocks-layout-deriver code is in: fs/nfs/blocklayout/.. directory
+
+objects-layout setup
+--------------------
+
+As part of the full STD implementation the objlayoutdriver.ko needs, at times,
+to automatically login to yet undiscovered iscsi/osd devices. For this the
+driver makes up-calles to a user-mode script called *osd_login*
+
+The path_name of the script to use is by default:
+ /sbin/osd_login.
+This name can be overridden by the Kernel module parameter:
+ objlayoutdriver.osd_login_prog
+
+If Kernel does not find the osd_login_prog path it will zero it out
+and will not attempt farther logins. An admin can then write new value
+to the objlayoutdriver.osd_login_prog Kernel parameter to re-enable it.
+
+The /sbin/osd_login is part of the nfs-utils package, and should usually
+be installed on distributions that support this Kernel version.
+
+The API to the login script is as follows:
+ Usage: $0 -u <URI> -o <OSDNAME> -s <SYSTEMID>
+ Options:
+ -u target uri e.g. iscsi://<ip>:<port>
+ (allways exists)
+ (More protocols can be defined in the future.
+ The client does not interpret this string it is
+ passed unchanged as recieved from the Server)
+ -o osdname of the requested target OSD
+ (Might be empty)
+ (A string which denotes the OSD name, there is a
+ limit of 64 chars on this string)
+ -s systemid of the requested target OSD
+ (Might be empty)
+ (This string, if not empty is always an hex
+ representation of the 20 bytes osd_system_id)
+
+blocks-layout setup
+-------------------
+
+TODO: Document the setup needs of the blocks layout driver
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