Re: Bcache stuck at writeback of a key, consuming 100% CPU, not possible to detach

[Emmanuel Florac <eflorac@intellique.com>]

Le Mon, 31 Aug 2015 16:49:49 +0200
Vojtech Pavlik <vojtech@suse.cz> écrivait:

> > 
> > The bcache_writeback stays at 100% _even_ when in writethrough mode,
> > alas. So this looks normal. However dirty_data definitely should
> > drop to zero...  
> 
> This most certainly isn't normal. The ftrace shows it's looping in a
> loop doing nothing useful.
> 

Yep, I've had a quick look at the code, however it's not very
inspiring. It very much looks like there's a missing test. From your
trace it looks like it finds a key_bad (?) -- from the struct
bch_extent_keys_ops in bcache/extents.c -- but there is no code anywhere
to manage this case apparently.

Ah, and I can't download your complete trace, too : twilight.ucw.cz
isn't responding. :)

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