From: Trond Myklebust Subject: Re: [PATCH 1/5] NFS: Update help text for CONFIG_NFS_FS Date: Mon, 04 Feb 2008 19:18:02 -0500 Message-ID: <1202170682.28484.55.camel@heimdal.trondhjem.org> References: <20080205000421.18602.44285.stgit@manray.1015granger.net> Mime-Version: 1.0 Content-Type: text/plain Cc: bfields@citi.umich.edu, linux-nfs@vger.kernel.org To: Chuck Lever Return-path: Received: from pat.uio.no ([129.240.10.15]:48407 "EHLO pat.uio.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757263AbYBEASJ (ORCPT ); Mon, 4 Feb 2008 19:18:09 -0500 In-Reply-To: <20080205000421.18602.44285.stgit-meopP2rzCrTwdl/1UfZZQIVfYA8g3rJ/@public.gmane.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, 2008-02-04 at 19:04 -0500, Chuck Lever wrote: > Refresh the help text for Kconfig items related to the NFS client. Remove > obsolete URLs, and make the language consistent among the options. > > Also move the ROOT_NFS config option next to the options related to the NFS > client. > > Signed-off-by: Chuck Lever > --- > > fs/Kconfig | 136 ++++++++++++++++++++++++++++++------------------------------ > 1 files changed, 69 insertions(+), 67 deletions(-) > > diff --git a/fs/Kconfig b/fs/Kconfig > index 987b5d7..5c7f6ee 100644 > --- a/fs/Kconfig > +++ b/fs/Kconfig > @@ -1517,10 +1517,6 @@ config UFS_FS > The recently released UFS2 variant (used in FreeBSD 5.x) is > READ-ONLY supported. > > - If you only intend to mount files from some other Unix over the > - network using NFS, you don't need the UFS file system support (but > - you need NFS file system support obviously). > - > Note that this option is generally not needed for floppies, since a > good portable way to transport files and directories between unixes > (and even other operating systems) is given by the tar program ("man > @@ -1560,6 +1556,7 @@ menuconfig NETWORK_FILESYSTEMS > Say Y here to get to see options for network filesystems and > filesystem-related networking code, such as NFS daemon and > RPCSEC security modules. > + > This option alone does not add any kernel code. > > If you say N, all options in this submenu will be skipped and > @@ -1574,44 +1571,35 @@ config NFS_FS > select SUNRPC > select NFS_ACL_SUPPORT if NFS_V3_ACL > help > - If you are connected to some other (usually local) Unix computer > - (using SLIP, PLIP, PPP or Ethernet) and want to mount files residing > - on that computer (the NFS server) using the Network File Sharing > - protocol, say Y. "Mounting files" means that the client can access > - the files with usual UNIX commands as if they were sitting on the > - client's hard disk. For this to work, the server must run the > - programs nfsd and mountd (but does not need to have NFS file system > - support enabled in its kernel). NFS is explained in the Network > - Administrator's Guide, available from > - , on its man page: "man > - nfs", and in the NFS-HOWTO. > - > - A superior but less widely used alternative to NFS is provided by > - the Coda file system; see "Coda file system support" below. > + Say Y here if you want to access files residing on other computers > + using the internet standard Network File System protocol. To Tsk, tsk.... NFS isn't an internet standard (yet!). > + compile this file system support as a module, choose M here: the > + module will be called nfs. > > - If you say Y here, you should have said Y to TCP/IP networking also. > - This option would enlarge your kernel by about 27 KB. > + To mount file systems exported by NFS servers, you also need to > + install the user space mount.nfs command which can be found in > + the Linux nfs-utils package, available from http://linux-nfs.org/. > + Information about using the mount command is available in the > + mount(8) man page. More detail about the Linux NFS client > + implementation is available via the nfs(5) man page. > > - To compile this file system support as a module, choose M here: the > - module will be called nfs. > + Below you can select which versions of the NFS protocol are > + available in the kernel to mount NFS servers. Support for NFS > + version 2 (RFC 1094) is always available when NFS_FS is selected. > > - If you are configuring a diskless machine which will mount its root > - file system over NFS at boot time, say Y here and to "Kernel > - level IP autoconfiguration" above and to "Root file system on NFS" > - below. You cannot compile this driver as a module in this case. > - There are two packages designed for booting diskless machines over > - the net: netboot, available from > - , and Etherboot, > - available from . > + To configure a system which mounts its root file system via NFS at > + boot time, say Y here, select "Kernel level IP autoconfiguration" > + in the NETWORK menu, and select "Root file system on NFS" below. > + You cannot compile this driver as a module in this case. > > - If you don't know what all this is about, say N. > + If unsure, say N. > > config NFS_V3 > bool "Provide NFSv3 client support" > depends on NFS_FS > help > - Say Y here if you want your NFS client to be able to speak version > - 3 of the NFS protocol. > + This option enables support for version 3 of the NFS protocol > + (RFC 1813) in the kernel's NFS client. > > If unsure, say Y. > > @@ -1619,9 +1607,21 @@ config NFS_V3_ACL > bool "Provide client support for the NFSv3 ACL protocol extension" > depends on NFS_V3 > help > - Implement the NFSv3 ACL protocol extension for manipulating POSIX > - Access Control Lists. The server should also be compiled with > - the NFSv3 ACL protocol extension; see the CONFIG_NFSD_V3_ACL option. > + Some NFS servers support an auxiliary NFSv3 ACL protocol that > + Sun added to Solaris but never became an official part of the > + NFS version 3 protocol. This nonstandard side-band protocol > + allows applications on NFS clients to manipulate POSIX Access > + Control Lists on files residing on NFS servers. NFS servers > + enforce ACLs on local files whether this protocol is available > + or not. > + > + Say Y here if your NFS server supports the Solaris NFSv3 ACL > + protocol and you want your NFS client to allow applications to > + access and modify ACLs on files on the server. > + > + Some NFS servers don't support the Solaris NFSv3 ACL protocol. ^^^^ Most? > + You can say N here or specify the "noacl" mount option to prevent > + your NFS client from trying to use the NFSv3 ACL protocol. > > If unsure, say N. > > @@ -1630,38 +1630,54 @@ config NFS_V4 > depends on NFS_FS && EXPERIMENTAL > select RPCSEC_GSS_KRB5 > help > - Say Y here if you want your NFS client to be able to speak the newer > - version 4 of the NFS protocol. > + This option enables support for version 4 of the NFS protocol > + (RFC 3530) in the kernel's NFS client. > > - Note: Requires auxiliary userspace daemons which may be found on > - http://www.citi.umich.edu/projects/nfsv4/ > + To mount NFS servers using NFSv4, you also need to install user > + space programs which can be found in the Linux nfs-utils package, > + available from http://linux-nfs.org/. > > If unsure, say N. > > config NFS_DIRECTIO > bool "Allow direct I/O on NFS files" > depends on NFS_FS > + default N Why? Isn't O_DIRECT pretty much a standard feature that is enabled in most distros at this time? IMO we should rather be aiming to phase out NFS_DIRECTIO. > help > - This option enables applications to perform uncached I/O on files > - in NFS file systems using the O_DIRECT open() flag. When O_DIRECT > - is set for a file, its data is not cached in the system's page > - cache. Data is moved to and from user-level application buffers > - directly. Unlike local disk-based file systems, NFS O_DIRECT has > - no alignment restrictions. > + This option enables support for uncached I/O on files accessed > + via an NFS mount point. Applications request direct I/O by > + setting the O_DIRECT flag when opening a file. > + > + When direct I/O is requested, the NFS client moves data to and > + from user-level application buffers directly to NFS servers. > + Direct I/O on NFS files does not suffer from any I/O or buffer > + alignment restrictions, as does direct I/O on files that reside > + in local file systems. > + > + For details, see the open(2) man page. > > Unless your program is designed to use O_DIRECT properly, you are > - much better off allowing the NFS client to manage data caching for > - you. Misusing O_DIRECT can cause poor server performance or network > - storms. This kernel build option defaults OFF to avoid exposing > + better off allowing the NFS client to manage data caching for you. > + Misusing O_DIRECT can cause poor server performance or network > + storms. This kernel build option defaults to N to avoid exposing > system administrators unwittingly to a potentially hazardous > feature. > > - For more details on NFS O_DIRECT, see fs/nfs/direct.c. > - > - If unsure, say N. This reduces the size of the NFS client, and > - causes open() to return EINVAL if a file residing in NFS is > + If unsure, say N. This reduces the size of the kernel NFS client, > + and causes open(2) to return EINVAL if a file residing in NFS is > opened with the O_DIRECT flag. > > +config ROOT_NFS > + bool "Root file system on NFS" > + depends on NFS_FS=y && IP_PNP > + help > + If you want your system to mount its root file system via NFS, say > + Y here. This is common practice for managing systems without > + local permanent storage. Read > + for details. > + > + Most people say N here. > + > config NFSD > tristate "NFS server support" > depends on INET > @@ -1738,20 +1754,6 @@ config NFSD_TCP > TCP connections usually perform better than the default UDP when > the network is lossy or congested. If unsure, say Y. > > -config ROOT_NFS > - bool "Root file system on NFS" > - depends on NFS_FS=y && IP_PNP > - help > - If you want your Linux box to mount its whole root file system (the > - one containing the directory /) from some other computer over the > - net via NFS (presumably because your box doesn't have a hard disk), > - say Y. Read for details. It is > - likely that in this case, you also want to say Y to "Kernel level IP > - autoconfiguration" so that your box can discover its network address > - at boot time. > - > - Most people say N here. > - > config LOCKD > tristate > > > - > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html