Re: ext4 features

[Bill Davidsen <davidsen@tmr.com>]

Benny Amorsen wrote:
>>>>>> "DC" == Diego Calleja <diegocg@gmail.com> writes:
> 
> DC> El Mon, 03 Jul 2006 15:46:55 -0600, "Jeff V. Merkey"
> DC> <jmerkey@wolfmountaingroup.com> escribió:
> 
>>> Add a salvagable file system to ext4, i.e. when a file is deleted,
>>> you just rename it and move it to a directory called DELETED.SAV
>>> and recycle the files as people allocate new ones. Easy to do
>>> (internal "mv" of
> 
> 
> DC> Easily doable in userspace, why bother with kernel programming
> 
> In userspace you can't automatically delete the files when the space
> becomes needed. The LD_PRELOAD/glibc methods also have the
> disadvantage of having to figure out where a file goes when it's
> deleted, depending on which device it happens to reside on. Demanding
> read access to /proc/mounts just to do rm could cause problems.
> 
> Userspace has had 10 years to invent a good solution. If it was so
> easy, it would probably have been done.
> 
Actually, if it were so important it WOULD have been done. I suspect 
that the issue is not lack of a good solution, but lack of a good 
problem. The behavior you propose requires a lot of kernel cleverness, 
including make the inodes seem to go away, so the count is "right" for 
what the user sees.

-- 
Bill Davidsen <davidsen@tmr.com>
   Obscure bug of 2004: BASH BUFFER OVERFLOW - if bash is being run by a
normal user and is setuid root, with the "vi" line edit mode selected,
and the character set is "big5," an off-by-one errors occurs during
wildcard (glob) expansion.