Re: [PATCH, RFC V3] ext4: limit block allocations for indirect-block files to < 2^32

[Eric Sandeen <sandeen@redhat.com>]

Andreas Dilger wrote:
> On Sep 10, 2009  16:16 -0500, Eric Sandeen wrote:
>> Any suggestions on the naming issues?  (what's the official name for a
>> "not-extent-based-file?")
> 
> I've always used "block mapped" (i.e. mapped block-by-block) vs.
> "extent mapped".
> 
>> However, Ric just ran a massive fs_mark test on a 60T filesystem that he
>> created with "mke2fs" (no extents and no journal - accidentally) and we
>> got no corruption even without this patch.
>>
>> I need to see if a filesystem w/o the extents feature (at all, vs. some
>> old-format files on an extents fs) never even tries to allocate past
>> 2^32; I didn't think so, but now not so sure.
> 
> Well, it may depend a lot on which inodes are in use.  That will set the
> goal block, and may prevent any above-16TB allocations.  Either you could

yep, though I had many, many inodes in the high groups ...

Problem is I don't quite trust debugfs etc to get it right, so when I
see < 32 bits, I'm not sure if it's really there, or if the
reporting/debug tool wrapped it ;)

-Eric