linux-ext4 - Re: [e2fsprogs] Bug in salvage

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Message-Id: <1184003549.4347.6.camel@garfield>
Date:	Mon, 09 Jul 2007 23:22:05 +0530
From:	Kalpak Shah <kalpak@...sterfs.com>
To:	Theodore Tso <tytso@....edu>
Cc:	linux-ext4 <linux-ext4@...r.kernel.org>,
	Andreas Dilger <adilger@...sterfs.com>
Subject: Re: [e2fsprogs] Bug in salvage_directory

On Mon, 2007-07-09 at 12:50 -0400, Theodore Tso wrote:
> On Mon, Jul 09, 2007 at 03:02:02PM +0530, Kalpak Shah wrote:
> > Hi Ted,
> > 
> > Recently, one of our customers found this message in pass2 of e2fsck while doing some regression testing:
> > "Entry '4, 0x695a, 0x81ff, 0x0040, 0x8320, 0xa192, 0x0021' in ??? (136554) has
> > rec_len of 14200, should be 26908."
> > 
> > Both the displayed rec_len and the "should be" value are bogus. The
> > reason is that salvage_directory sets a offset beyond blocksize
> > leading to bogus messages.
> 
> Do you have a test case where this happens?  I don't think your patch
> is right, because if dirent->rec_len is too big, this yes, your patch
> will make sure offset doesn't get set beyond fs->blocksize, but it
> ends up leaving prev->rec_len also pointing beyond fs->blocksize ---
> which means a 2nd e2fsck should result in a complaint about that.

Yes even prev->rec_len cannot be beyond fs->blocksize. I do have the
corrupt filesystem image but it is a large one. 

This patch certainly works well and corrects the problem in a single run
of e2fsck.

Thanks,
Kalpak.

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