linux-ext4 - Re: [RFC][PATCH 1/7]ext4: Add EXT4_IOC_ADD_GLOBAL_ALLOC

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 linux-cve-announce 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]

Message-id: <20090624001158.GQ31668@webber.adilger.int>
Date:	Wed, 24 Jun 2009 02:11:58 +0200
From:	Andreas Dilger <adilger@....com>
To:	Greg Freemyer <greg.freemyer@...il.com>
Cc:	Akira Fujita <a-fujita@...jp.nec.com>, linux-ext4@...r.kernel.org,
	"Theodore Ts'o" <tytso@....edu>, linux-fsdevel@...r.kernel.org
Subject: Re: [RFC][PATCH 1/7]ext4: Add EXT4_IOC_ADD_GLOBAL_ALLOC_RULE	restricts
 block allocation

On Jun 23, 2009  20:02 -0400, Greg Freemyer wrote:
> On Tue, Jun 23, 2009 at 7:19 PM, Andreas Dilger<adilger@....com> wrote:
> > On Jun 23, 2009  17:25 +0900, Akira Fujita wrote:
> >> alloc_flag of ext4_alloc_rule structure is set as "mandatory" or "advisory".
> >> Restricted blocks with "mandatory" are never used by block allocator.
> >> But in "advisory" case, block allocator is allowed to use restricted blocks
> >> when there are no free blocks on FS.
> >
> > Would it make more sense to implement the range protections via the
> > existing preallocation ranges (PA)?  An inode can have multiple
> > PAs attached to it to have it prefer allocations from that range.
> >
> > We could also attach PAs to the superblock to prevent other files from
> > allocating out of those ranges.  This would work better with the existing
> > allocation code instead of creating a second similar mechanism.
> 
> Where can I find documentation about how PA works?  Or is it just in
> the source?  If so, what are one or two calls that cause the PA ranges
> to be set, etc.

Aneesh is the expert on the preallocation code.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.

--
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