broken commit 25567a7b0fa98b390fd1ff0d4702b29c23a75bbb

broken commit 25567a7b0fa98b390fd1ff0d4702b29c23a75bbb

[Andreas Dilger]

In my pull from e2fsprogs git "master" branch, it contains commit
25567a7b0fa98b390fd1ff0d4702b29c23a75bbb "support for bigalloc
file systems with a blocksize of 1024" that deletes the initialization
of the flexbg_size variable from lib/ext2fs/alloc_tables.c::flexbg_offset():

-       flexbg_size = 1 << fs->super->s_log_groups_per_flex;
-       flexbg = group / flexbg_size;
+       size = rem_grp * elem_size;

but it continues to use flexbg_size later on in this function:

       start_blk = ext2fs_group_first_block2(fs, flexbg_size * flexbg);
       last_grp = group | (flexbg_size - 1);

This provokes an uninitialized compiler warning (I always use CFLAGS=-Wall),
but it isn't clear to me at first glance what the intention of this change
is or how to fix it.

It doesn't cause any "make check" errors, but that is almost certainly
only because very few tests run with flex_bg enabled, but it is definitely
a bug that would cause strange behaviour.

Cheers, Andreas

Re: broken commit 25567a7b0fa98b390fd1ff0d4702b29c23a75bbb

[Ted Ts'o]

On Fri, Jul 08, 2011 at 06:07:14PM -0600, Andreas Dilger wrote:
> In my pull from e2fsprogs git "master" branch, it contains commit
> 25567a7b0fa98b390fd1ff0d4702b29c23a75bbb "support for bigalloc
> file systems with a blocksize of 1024" that deletes the initialization
> of the flexbg_size variable from lib/ext2fs/alloc_tables.c::flexbg_offset():
> 
> -       flexbg_size = 1 << fs->super->s_log_groups_per_flex;
> -       flexbg = group / flexbg_size;
> +       size = rem_grp * elem_size;
> 
> but it continues to use flexbg_size later on in this function:

Yeah, sorry, fixed in the next branch.  I thought I had advanced the
master branch enough to fix it, but I didn't advance it enough.  Try a
pull now.

						- Ted