Re: [patch 0/15] LogFS take five

[Jens Axboe]

On Tue, Apr 01 2008, joern@xxxxxxxxx wrote:
> And it is currently reasonably simple to run into a deadlock when
> using logfs on a block device.  The problem appears to be the block
> layer allocating memory for its cache without GFP_NOFS, so that under
> memory pressure logfs writes through block layer may recurse back to
> logfs writes.

So you mean for writes through the page cache, you are seeing pages
allocated with __GFP_FS set?

> Not entirely sure who is to blame for this bug and how to
> solve it.

A good starting point would be doing a stack trace dump in logfs if you
see such back recursion into the fs. A quick guess would be a missing
setting of mapping gfp mask?

-- 
Jens Axboe

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