From 18d98f6c04991dd3c12acf6f39cea40e9510640a Mon Sep 17 00:00:00 2001 From: Sachin Bhamare Date: Mon, 19 Mar 2012 20:47:58 -0700 Subject: pnfs-obj: autologin: Add support for protocol autologin The pnfs-objects protocol mandates that we autologin into devices not present in the system, according to information specified in the get_device_info returned from the server. The Protocol specifies two login hints. 1. An IP address:port combination 2. A string URI which is constructed as a URL with a protocol prefix followed by :// and a string as address. For each protocol prefix the string-address format might be different. We only support the second option. The first option is just redundant to the second one. NOTE: The Kernel part of autologin does not parse the URI string. It just channels it to a user-mode script. So any new login protocols should only update the user-mode script which is a part of the nfs-utils package, but the Kernel need not change. We implement the autologin by using the call_usermodehelper() API. (Thanks to Steve Dickson for pointing it out) So there is no running daemon needed, and/or special setup. We Add the osd_login_prog Kernel module parameters which defaults to: /sbin/osd_login Kernel try's to upcall the program specified in osd_login_prog. If the file is not found or the execution fails Kernel will disable any farther upcalls, by zeroing out osd_login_prog, Until Admin re-enables it by setting the osd_login_prog parameter to a proper program. Also add text about the osd_login program command line API to: Documentation/filesystems/nfs/pnfs.txt and documentation of the new osd_login_prog module parameter to: Documentation/kernel-parameters.txt TODO: Add timeout option in the case osd_login program gets stuck Signed-off-by: Sachin Bhamare Signed-off-by: Boaz Harrosh Signed-off-by: Trond Myklebust --- Documentation/filesystems/nfs/pnfs.txt | 54 ++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) (limited to 'Documentation/filesystems') diff --git a/Documentation/filesystems/nfs/pnfs.txt b/Documentation/filesystems/nfs/pnfs.txt index 983e14abe7e..c7919c6e3be 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 -o -s + Options: + -u target uri e.g. iscsi://: + (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 -- cgit v1.2.3-70-g09d2