Re: [Ext2-devel] [RFC 0/13] extents and 48bit ext3

From: Qi Yong
Date: Tue Jun 20 2006 - 02:14:13 EST


Linus Torvalds wrote:

On Fri, 9 Jun 2006, Stephen C. Tweedie wrote:


When is the Linux syscall interface enough? When should we just bump it
and cut out all the compatibility interfaces?

No, we don't; we let people configure certain obsolete bits out (a.out
support etc), but we keep it in the tree despite the indirection cost to
maintain multiple interfaces etc.



Right. WE ADD NEW SYSTEM CALLS. WE DO NOT EXTEND THE OLD ONES IN WAYS THAT MIGHT BREAK OLD USERS.

Your point was exactly what?

Btw, where did that 2TB limit number come from? Afaik, it should be 16TB for a 4kB filesystem, no?



Partition tables describe partitions in units of one sector.
2^(32+9) = 2T

To prevent integer overflow, we should use only 31 bits of a 32-bit integer.
2^(31+12) = 8T

There's _terrible_ hacks to really get to 16T.

-- qiyong
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