From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756539Ab2IQO2G (ORCPT ); Mon, 17 Sep 2012 10:28:06 -0400 Received: from fieldses.org ([174.143.236.118]:59867 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756335Ab2IQO2E (ORCPT ); Mon, 17 Sep 2012 10:28:04 -0400 Date: Mon, 17 Sep 2012 10:28:00 -0400 From: "J. Bruce Fields" To: Namjae Jeon Cc: hirofumi@mail.parknet.co.jp, akpm@linux-foundation.org, viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org, Namjae Jeon , Ravishankar N , Amit Sahrawat Subject: Re: [PATCH v3 5/5] Documentation: update nfs option in filesystem/vfat.txt Message-ID: <20120917142800.GH30673@fieldses.org> References: <1347798200-2765-1-git-send-email-linkinjeon@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1347798200-2765-1-git-send-email-linkinjeon@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Sep 16, 2012 at 08:23:20AM -0400, Namjae Jeon wrote: > From: Namjae Jeon > > update nfs option in filesystem/vfat.txt > > Signed-off-by: Namjae Jeon > Signed-off-by: Ravishankar N > Signed-off-by: Amit Sahrawat > --- > Documentation/filesystems/vfat.txt | 19 ++++++++++++++----- > 1 file changed, 14 insertions(+), 5 deletions(-) > > diff --git a/Documentation/filesystems/vfat.txt b/Documentation/filesystems/vfat.txt > index de1e6c4..3371b8e 100644 > --- a/Documentation/filesystems/vfat.txt > +++ b/Documentation/filesystems/vfat.txt > @@ -141,13 +141,22 @@ discard -- If set, issues discard/TRIM commands to the block > device when blocks are freed. This is useful for SSD devices > and sparse/thinly-provisoned LUNs. > > -nfs -- This option maintains an index (cache) of directory > - inodes by i_logstart which is used by the nfs-related code to > - improve look-ups. > - > - Enable this only if you want to export the FAT filesystem > +nfs=full_unstable|limited_stable You still want to accept just "nfs" (defaulting to "full_unstable" behavior), for backwards compatibility. Also I don't find this full_unstable/limited_stable terminology very intuitive. "stable" and "limited" could mean too many different things. Maybe "nostale_ro|stale_rw" ? > + -- Enable this only if you want to export the FAT filesystem > over NFS > > + full_unstable:This option maintains an index (cache) of > + directory inodes by i_logstart which is used by > + the nfs-related code to improve look-ups.Full file operations > + (read/write) over NFS is supported but with cache eviction > + at NFS server, this could result in ESTALE issues. > + > + limited_stable:This options makes NFS support for FAT as > + read-only and provides stable inode based on the on-disk > + location of the MS-DOS directory entry.This helps in > + reconstruction of the inodes in case of lookup failure, > + making FAT behaviour stable with respect to ESTALE issues. This option still scares me a little. Maybe a little more explanation: This option bases the inode number and filehandle on the location of an file in the MS-DOS directory entry. This ensures that ESTALE will not be returned after a file is evicted from the inode cache. However, it means that operations such as rename, create, and unlink could cause filehandles that previously pointed at one file to point at a different file, potentially causing data corruption. For this reason, this option also mounts the filesystem readonly. --b. > + > : 0,1,yes,no,true,false > > TODO > -- > 1.7.9.5 >