From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marco Stornelli Subject: Re: [PATCH 01/17] pramfs: documentation Date: Sat, 08 Jan 2011 09:16:37 +0100 Message-ID: <4D281D65.1070102@gmail.com> References: <4D25AF02.60208@gmail.com> <4D2777FC.6040509@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Linux Kernel , Linux Embedded , Linux FS Devel , Tim Bird To: Tony Luck Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On 07/01/2011 22:59, Tony Luck wrote: > On Fri, Jan 7, 2011 at 12:30 PM, Marco Stornelli > wrote: >> constraint). About the errors: pramfs does not maintain file data in the >> page caches for normal file I/O, so no writeback, the read/write >> operation are done with direct io and they are always sync. The data are >> write protected in hw when the arch provide this facility (x86 does). >> Inode contains a checksum and when there are problems they are marked as >> bad. Superblock contains checksum and there is a redundant superblock. > > But you can still get pramfs inconsistencies if the system crashes at an > inopportune moment. E.g. when making files you write the new inode to > pramfs, and then you insert the entry into the directory. A crash between > these two operations leaves an allocated inode that doesn't appear in > any directory. Without a fsck option, it will be hard to see that you have > this problem, and your only recovery option is to wipe *all* files by making > a new filesystem. Is it a problem if you lost some logs? However do you expect that fsck in this case will drop the inode?