Re: [Nbd] NBD, DISCARD/TRIM

[folkert <folkert@...421...>]

> >> I had suspected the kill_bdev patch, as it's the only thing of any
> >> significance that has changed recently related to nbd shutdown, but it
> >
> > As a note: this does not happen during shutdown. Well, maybe it does but
> > that was not invoked at the time of the crash.
> > The test was:
> >  mount /dev/nbd0 /mnt -o noatime,discard,barrier=1  (or without -o)
> >  and then on that mountpoint
> >  iozone3 [...]
> So maybe iozone is doing something odd here? Can you make this happen
> without that?

Well iozone3 works on files, not directly on the device so from the nbd
point of view nothings strange happens. I did see it happen too with a
script I wrote that did all kinds of things in parallel: iso copy, tar
of kernel sources. Unfortunately I lost that script.

> >> As for what is causing your client to stop in the first place, I'm not
> >> sure. How do you have the FS mounted? Are you testing discard, i.e.,
> >> you have the option enabled in the nbd-server?
> >
> > As I wrote above.
> > But also with just plain mount /dev/nbd0 /mnt. This is always with a
> > filesystem build with mkfs.ext4 -j. Furthermore, this is with the stock
> 
> You're saying _any_ mount of ext4 over nbd does this sudden shutdown,
> with 3.2+ kernel? Surely that's not the case?

Yes, it does unfortunately.


Folkert van Heusden

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