Re: [linux-pm] pm loss development

[Alan Cox]

> I know nothing about journalling file systems or how well they limit the
> critical sections of time where the file system is exposed to corruption
> from sudden power failure.  Its an interesting question though.

A properly written journalling file system has no critical sections. The
only things it relies upon are

- store ordering in the drive working properly
- a single disk block write being atomic

the former is well specified even for ATA devices, the latter is a pretty
safe property of rotating media, although in theory you have a finite
chance of getting a bad sector.

For flash it's a lot lot more complicated but for a flash device claiming
to be ATA compliant you ought to get ATA behaviour.

All that said there is still (as ever) a tiny chance your system may
malfunction. It's all down to probabilities and if your laptop explodes
you need a backup (trust me, I've tested this case).

Alan

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