[Ocfs2-devel] [PATCH 2/3] ocfs2: implement discontiguous localalloc bitmap

[Srinivas Eeda <srinivas.eeda@oracle.com>]

Joel Becker wrote:
> On Mon, May 07, 2012 at 04:21:29PM -0700, Srinivas Eeda wrote:
>   
>
> 	OH MY DOG NO.  NEVER EVER DO THIS.  You cannot update an old
> filesystem on the fly!  What about other nodes that are running older
> versions of the software?  They will crash or corrupt data!  The entire
> point of feature bits is to make sure all nodes are speaking the same
> code.
>
> NAK NAK NAK
>
> 	This explains why you trusted la_rec_count earlier.  But that is
> broken.  When your patches are done, the code should use la_bm_off and
> la_bitmap when !DISCONTIG_LA and then use la_rec_count, etc when
> DISCONTIG_LA.  The only way to transition between them is a tunefs.ocfs2
> operation that walks the filesystem, flushes the bitmap, and then
> sets/clears la_rec_count appropriately depending on the direction..
>   
Please please don't hate me :( ... the changes takes care of old formats 
as well ...  I used the reserved space in the structure so that the code 
changes will be minimal and still compatible with old file system 
formats. I agree that we need to have some reserved space still 
available. So as discussed I'll redo the changes accordingly. Please 
ignore all the patches.

Thanks,
--Srini