Re: [PATCH 2/2] OCFS2: Allow huge (> 16 TiB) volumes to mount

[Andreas Dilger <adilger@dilger.ca>]

On 2010-07-12, at 19:08, Patrick J. LoPresti wrote:
> On Mon, Jul 12, 2010 at 5:21 PM, Andreas Dilger <adilger@dilger.ca> wrote:
>> On 2010-07-11, at 11:04, Patrick J. LoPresti wrote:
>>> 
>>> +     /* Absolute addressability check (borrowed from ext4/super.c) */
>>> +     if ((max_block >
>>> +          (sector_t)(~0LL) >> (osb->sb->s_blocksize_bits - 9)) ||
>>> +         (max_block > (pgoff_t)(~0LL) >> (PAGE_CACHE_SHIFT -
>>> +                                          osb->sb->s_blocksize_bits))) {
>>> +             mlog(ML_ERROR, "Volume too large "
>>> +                  "to mount safely on this system");
>>> +             status = -EFBIG;
>>> +             goto out;
>>> +     }
>> 
>> This hunk of code is actually in several filesystems.  It wouldn't be a bad idea to make it a library function that can be called by the filesystem to check the kernel page cache and block layer can handle these large filesystems.
> 
> True, but some of them do it differently (e.g. see the #if switch in
> xfs_sb_validate_fsb_count).  Tracking down all variants and changing
> them is a much larger task than my simple patch.
> 
> Are you suggesting I need to do this before my patch is accepted at
> all?  Or is this a refactoring that can happen later?

I'm just suggesting it should be done at some point.  I thought it would be better to do it first, rather than add yet another copy of this code.  That said, I hate to block useful fixes because of cleanup (and I have no control over OCFS2 anyway :-).  However, I've found that once the fix is in people usually forget (or become too busy) to do the cleanup and it just lingers on unseen.

Cheers, Andreas