Re: Block layer projects that I haven't had time for

[Dongsu Park]

On 11.12.2014 22:32, Ming Lin wrote:
> On 12/11/2014 02:07 AM, Dongsu Park wrote:
> > On 10.12.2014 23:11, Ming Lin wrote:
> >> Just tried to edit a btrfs file.
> >>
> >> [   45.216351] BTRFS error (device sdb1): partial page write in btrfs with
> >> offset 0 and length 8192
> >> [   45.217522] BTRFS critical (device sdb1): bad ordered accounting left 0
> >> size 4096
> > 
> > @ming: I guess you managed to see this error as you're testing with a
> > SCSI device, not virtio-blk device like me.
> > Are you seeing it without any back traces?
> > Does the attached patch fix your issue?
> > (This is already included in the branch block-mpage-bvecs-for-next.)
> 
> How about below fix?
> "bvec.bv_len != PAGE_CACHE_SIZE" should be not valid any more, because now bio
> handles arbitrary size, right?

Thanks for figuring it out. :-)
I applied the change not only in _writepage(), but also in _readpage(),
also with some minor changes. See the attached patch.

I've just tested it under btrfs on a SCSI device via scsi_debug.
No such errors any more. Hope it works also for you.
Probably there will be a lot of places where a single page is assumed.

Cheers,
Dongsu

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