Corruption of root fs during git bisect of drm system hang

[Markus Trippelsdorf]

On 2013.07.11 at 10:31 +1000, Dave Chinner wrote:
> On Wed, Jul 10, 2013 at 11:06:34AM +0200, Markus Trippelsdorf wrote:
> > While bisecting a system hang, caused by the drm gpu subsystem, my root fs got
> > corrupted:
> 
> I don't see any corruption being repaired....
> 
> > 
> >  # xfs_repair /dev/sdc2
> > Phase 1 - find and verify superblock...
> > Phase 2 - using internal log
> >         - zero log...
> >         - scan filesystem freespace and inode maps...
> > agi unlinked bucket 6 is 682886 in ag 3 (inode=101346182)
> > agi unlinked bucket 7 is 11335 in ag 3 (inode=100674631)
> > agi unlinked bucket 10 is 682890 in ag 3 (inode=101346186)
> > agi unlinked bucket 21 is 981 in ag 3 (inode=100664277)
> > agi unlinked bucket 23 is 5704343 in ag 3 (inode=106367639)
> > agi unlinked bucket 29 is 211421 in ag 3 (inode=100874717)
> > agi unlinked bucket 31 is 7681375 in ag 3 (inode=108344671)
> > agi unlinked bucket 34 is 3480162 in ag 3 (inode=104143458)
> > agi unlinked bucket 40 is 211432 in ag 3 (inode=100874728)
> > agi unlinked bucket 41 is 2704937 in ag 3 (inode=103368233)
> > agi unlinked bucket 45 is 594669 in ag 3 (inode=101257965)
> > agi unlinked bucket 62 is 11902 in ag 3 (inode=100675198)
> 
> That's a filesystem that has unlinked inodes on the unlinked list.
> They get cleaned up during log replay. All the other "errors" are
> related to cleaning these up....
> 
> So what is making you think there is a corruption? What's the error
> being reported when you are using the filesystem? i.e. what's the
> entire process you go through before you get to finding this
> problem?

I was loosing my KDE settings bit by bit with every reboot during the
bisection. First my window-rules disappeared, then my desktop background
changed to default, then my taskbar moved from top to the bottom, etc.
In the end I had to restore all my .files from backup. 
And please note that xfs_repair unlinked the inodes _after_ the
filesystem has been mounted and unmounted normally. 

-- 
Markus