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From: Ted Ts'o <tytso@mit.edu>
To: Yongqiang Yang <xiaoqiangnk@gmail.com>
Cc: linux-ext4@vger.kernel.org
Subject: Re: [PATCH 3/3] e2fsprogs: add a function computing old desc blocks without reserved ones
Date: Mon, 23 Jan 2012 11:45:27 -0500	[thread overview]
Message-ID: <20120123164527.GA4439@thunk.org> (raw)
In-Reply-To: <1325674932-26069-3-git-send-email-xiaoqiangnk@gmail.com>

On Wed, Jan 04, 2012 at 07:02:12PM +0800, Yongqiang Yang wrote:
> If first_meta_bg > desc_blocks, ext2fs_open reads more decs_blocks,
> however desc buffer in memory is allocated based on desc_blocks.
> Maybe there are similar problems in other places, so this patch adds a
> function which computes right old_desc_blocks.
> 
> The problem can be reproduced by setting first_meta_bg.

s_first_meta_bg should never be greater than desc_blocks.  If it is,
the file system is corrupt.  This is something that we should check in
ext2fs_open() and in e2fsck as well.

A much better thing to do would be to have ext2fs_open simply fail the
open with an EXT2_ET_CORRUPT_SUPERBLOCK error.  Then e2fsck will
automatically try using the backup superblock, which will hopefully
allow the user to recover from the corrupted superblock.

      	       	  	       	   	     - Ted

  reply	other threads:[~2012-01-23 18:09 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-04 11:02 [PATCH V2 1/3] mke2fs: correct help text for option -G of mke2fs Yongqiang Yang
2012-01-04 11:02 ` [PATCH 2/3] e2fsprogs: move code computing old_desc_blocks to a function Yongqiang Yang
2012-01-23 16:56   ` Ted Ts'o
2012-01-04 11:02 ` [PATCH 3/3] e2fsprogs: add a function computing old desc blocks without reserved ones Yongqiang Yang
2012-01-23 16:45   ` Ted Ts'o [this message]
2012-01-23 16:47 ` [PATCH V2 1/3] mke2fs: correct help text for option -G of mke2fs Ted Ts'o

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