Re: [PATCH 0/3] Handle bad dev_root properly with rescue=all

On 3/17/21 8:27 AM, David Sterba wrote:

On Thu, Mar 11, 2021 at 11:23:13AM -0500, Josef Bacik wrote:

quoted

Hello,

My recent debugging session with Neal's broken filesystem uncovered a glaring
hole in my rescue=all patches, they don't deal with a NULL dev_root properly.
In testing I only ever tested corrupting the extent tree or the csum tree, since
those are the most problematic.  The following 3 fixes allowed Neal to get
rescue=all working without panicing the machine, and I verified everything by
using btrfs-corrupt-block to corrupt a dev root of a file system.  Thanks,

When rescue= is set lots of things can't work, I was wondering if we
should add messages once the "if (!dev_root)" cases are hit but I don't
think we need it, it should be clear enough from the other rescue=
related messages.

Yeah I went back and forth on this, and I came to the same conclusion as you. 
If we're doing rescue=all we know things are bad, and we just want our data 
back.  Thanks,

Josef