linux-ext4 - Re: [PATCH 10/18] e2fsck: write dir blocks after new inode when reconstructing root/lost+found

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Date:	Sat, 26 Jul 2014 17:18:46 -0400
From:	Theodore Ts'o <tytso@....edu>
To:	"Darrick J. Wong" <darrick.wong@...cle.com>
Cc:	linux-ext4@...r.kernel.org
Subject: Re: [PATCH 10/18] e2fsck: write dir blocks after new inode when
 reconstructing root/lost+found

On Fri, Jul 25, 2014 at 05:34:41PM -0700, Darrick J. Wong wrote:
> If we trash the root directory block, e2fsck will find inode 11 (the
> old lost+found) and try to attach it to l+f.  The lost+found checker
> also fails to find l+f and tries to add one to the root dir.  The root
> dir is not found but is recreated with incorrect checksums, so linking
> in the l+f dir fails and the l+f '..' entry isn't set.  Since both
> dirs now fail checksum verification, they're both referred to rehash
> to have that fixed, but because l+f doesn't have a '..' entry, rehash
> crashes because l+f has < 2 entries.
> 
> On a checksumming filesystem, the routines in e2fsck that recreate
> /lost+found and / must write the new directory block *after* the inode
> has been written to disk because the checksum depends on i_generation.
> Add a regression test while we're at it.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com>

Thanks, applied.

						- Ted
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