Phillip Lougher phillip.lougher at gmail.com
Wed May 14 13:49:01 UTC 2008

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");


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