Race to power off harming SATA SSDs

[David Woodhouse]

On Mon, 2017-05-08 at 11:28 +0200, Pavel Machek wrote:
> 
> Are you sure you have it right in JFFS2? Do you journal block erases?
> Apparently, that was pretty much non-issue on older flashes.

It isn't necessary in JFFS2. It is a *purely* log-structured file
system (which is why it doesn't scale well past the 1GiB or so that we
made it handle for OLPC).

So we don't erase a block until all its contents are obsolete. And if
we fail to complete the erase... well the contents are either going to
fail a CRC check, or... still be obsoleted by later entries elsewhere.

And even if it *looks* like an erase has completed and the block is all
0xFF, we erase it again and write a 'clean marker' to it to indicate
that the erase was completed successfully. Because otherwise it can't
be trusted.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/x-pkcs7-signature
Size: 4938 bytes
Desc: not available
URL: <http://lists.infradead.org/pipermail/linux-mtd/attachments/20170508/f95ae320/attachment.bin>