Re: xt4 - True Readonly mount [WAS - Re: [Bug 14354] Bad corruption with 2.6.32-rc1 and upwards]

2009/10/30 Eric Sandeen [off-list ref]:

Alexey Fisher wrote:

quoted

Hmm... bdev. any chance to do temporary recovery and load it as external
journal if ro used? Anyway, you already pointed me to hdparm, so i can
use it too.

There were patches floated to in-ram recovery for those blocks so that you
could have a consistent fs w/o touching the disk but it didn't seem to get
far.

Those were mine, I think. I got stuck at the point of needing to
handle escaped blocks -- I couldn't find any way of reliably and
efficiently getting hold of a buffer after it had been read from disk
but before anybody else had a chance to access it. I think if I could
have cracked that then I could have got it working. The only other
missing piece of functionality was handling the transition from
read-only (unrecovered) to read-write.

It would have needed a very thorough audit of the places where ext3
was doing ll_rw_block and such like, though.

Cheers,
Duane.

-- 
"I never could learn to drink that blood and call it wine" - Bob Dylan