lzma

Tim Gardner tcanonical at tpi.com
Fri May 16 06:58:10 UTC 2008


Phillip Lougher wrote:
> On Wed, May 14, 2008 at 12:17 PM, Alessio Igor Bogani
> <abogani at texware.it> wrote:
>> Hi Kernel Team,
>>
>>  I'm sure that someone will request it at UDS. :-)
>>
>>       UBUNTU: Add lzma support
>>       UBUNTU: Add lzma support in squashfs kernel module
>>
> 
> You don't mention where you got the squashfs-lzma patches from, I
> assume they're unmodified patches from http://www.squashfs-lzma.org?
> 
> I'm not going to comment on the merits of adding these patches to
> Squashfs in the Ubuntu kernel, I have mentioned elsewhere (as the
> author of Squashfs) my reluctance and the reasons for my reluctance in
> supporting lzma in Squashfs.  All I will say is it is very likely
> Squashfs will be merged into the mainline kernel later this year, but
> it is extremely unlikely the mainline version will ever support lzma.
> 
> However, there is an important bug in the patches.  The following
> change is wrong.  If these patches are incorporated, this change
> should be removed.  The inode_number in the squashfs_dir_entry is a
> signed 16 bit difference from the reference 32 bit inode_number stored
> in the squashfs_dir_header.
> 
> --- a/ubuntu/fs/squashfs/linux/squashfs_fs.h
> +++ b/ubuntu/fs/squashfs/linux/squashfs_fs.h
> @@ -341,7 +341,7 @@ struct squashfs_dir_entry {
>         unsigned int            offset:13;
>         unsigned int            type:3;
>         unsigned int            size:8;
> -       int                     inode_number:16;
> +       unsigned int            inode_number:16;
>         char                    name[0];
>  } __attribute__ ((packed));
> 
> 
> The following change in inode.c is also wrong, it reverts the version
> of Squashfs to 3.2-r2-CVS.  The version of Squashfs in the Ubuntu
> kernel is Squashfs 3.3.
> 
> -MODULE_DESCRIPTION("squashfs 3.3, a compressed read-only filesystem");
> -MODULE_AUTHOR("Phillip Lougher <phillip at lougher.demon.co.uk>");
> +MODULE_DESCRIPTION("squashfs 3.2-r2-CVS, a compressed read-only
> filesystem, and LZMA suppport for slax.org");
> +MODULE_AUTHOR("Phillip Lougher <phillip at lougher.demon.co.uk>, and
> LZMA suppport for slax.org by jro");
> 
> Phillip
> 

Phillip - can you point me at your arguments regarding lzma so I can at
least appear somewhat knowledgeable when asked? The
www.squashfs-lzma.org site doesn't go into much detail. Thanks.

-- 
Tim Gardner tim.gardner at ubuntu.com




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