Re: [PATCH 01/11] btrfs: add missing device::flush_bio puts

[David Sterba <dsterba@suse.cz>]

On Thu, Nov 02, 2017 at 11:41:44AM +0200, Nikolay Borisov wrote:
> 
> 
> On 31.10.2017 19:44, David Sterba wrote:
> > This fixes potential bio leaks, in several error paths. Unfortunatelly
> > the device structure freeing is opencoded in many places and I missed
> > them when introducing the flush_bio.
> > 
> > Most of the time, devices get freed through call_rcu(..., free_device),
> > so it at least it's not that easy to hit the leak, but it's still
> > possible through the path that frees stale devices.
> > 
> > Fixes: e0ae99941423 ("btrfs: preallocate device flush bio")
> > Signed-off-by: David Sterba <dsterba@suse.com>
> 
> Verified that every kfree(device) has a matching bio_put via:
> 
> grep -ir -B2 "kfree(dev.*)" fs/btrfs/volumes.c

I've used this coccinelle script to cross-check, in case the variable is
is not named 'dev*':

<smpl>
@@
struct btrfs_device *DEV;
@@
* kfree(DEV);
</smpl>