Re: Flash erase groups and filesystems

[Pavel Machek <pavel@ucw.cz>]

Hi!

> >Question came up before, albeit with a different phrasing.  One
> >possible approach to benefit from this ability would be to create a
> >"forget" operation.  When a filesystem already knows that some data is
> >unneeded (after a truncate or erase operation), it will ask the device
> >to forget previously occupied blocks.
> >
> >The device then has the _option_ of handling the forget operation.
> >Further reads on these blocks may return random data.
> >
> >And since noone stepped up to implement this yet, you can still get
> >all the fame and glory yourself! ;)
> >  
> >
> 
> I'm not sure we're talking about the same thing. I'm not suggesting new
> features in the VFS layer. I want to know if something breaks if I
> implement this erase feature in the MMC layer. In essence the file
> system has marked the sectors as "forget" by issuing a write to them.
> The question is if it is assumed that they are unchanged if the write
> fails half-way through.

Journaling filesystems may not like finding 0xff's all over their journal...
-- 
64 bytes from 195.113.31.123: icmp_seq=28 ttl=51 time=448769.1 ms