lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Sun, 18 Mar 2012 16:41:53 -0400
From:	Ted Ts'o <tytso@....edu>
To:	Phillip Susi <psusi@...ntu.com>
Cc:	Andreas Dilger <adilger@...ger.ca>,
	ext4 development <linux-ext4@...r.kernel.org>
Subject: Re: Status of META_BG?

On Thu, Mar 15, 2012 at 01:55:36PM -0400, Phillip Susi wrote:
> >META_BG addresses both of these issues by distributing the group
> >descriptor blocks into the filesystem for each "meta group" (= the
> >number of groups whose descriptors fit into a single block).
> 
> So it puts one GD block at the start of every several block groups?
> Wouldn't that drastically slow down opening/mounting the fs since
> the disk has to seek to every block group?

Not necessarily; right now we pull in every single block group
descriptor at mount time because we need to update s_free_inodes_count
and s_free_blocks_count.  If we change things so that we only pull in
the block group descriptors at mount time after a journal replay (but
not after a clean umount, when the last inodes count and free blocks
count should be correctly updated), that would avoid seeking to every
16th block group at mount time.  

						- Ted
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Powered by blists - more mailing lists