[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Flash erase groups and filesystems
Jörn Engel wrote:
>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.
I'd have to say that this is a dangerous assumption to make already
today since some systems might not be able to tell where it fails if a
large chunk of data is given to it, perhaps because of a deep pipeline
before it actually reaches the physical storage.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/