Re: video archive on a microSD card

[Jaegeuk Kim <jaegeuk@kernel.org>]

On Wed, Aug 31, 2016 at 11:52:00AM +0300, Alexander Gordeev wrote:
> Hi Jaegeuk,
> 
> 29.08.2016, 21:00, "Jaegeuk Kim" <jaegeuk@kernel.org>:
> > On Mon, Aug 29, 2016 at 07:50:24PM +0300, Alexander Gordeev wrote:
> >>  Hi,
> >>
> >>  I have an update about the first of the bugs, that I reported.
> >>
> >>  19.08.2016, 20:23, "Alexander Gordeev" <alex@gordick.net>:
> >>  > Hi,
> >>  >
> >>  > I'd also like to report two bugs. I used f2fs-stable branch linux-3.10.y.
> >>  > I'm using some proprietary modules also, but in my understanding they shouldn't affect the fs.
> >>  >
> >>  > 1. I have a Sandisk 16GB microSDHC card, that is quite old and may be at its end of life.
> >>  > The bug is produced every time I try to delete any file on it.
> >>  >
> >
> > ...
> >
> >>  As you can see, after to warnings goes an oops. I think it was overlooked.
> >>  But it makes the most trouble to me.
> >>
> >>  I tried to understand what's going on.
> >>  It turns out that se->cur_valid_map is NULL in update_sit_entry().
> >>  Probably, this is not expected.
> >
> > Thank you for the analysis. :)
> > It seems the blkaddr is out-of-range.
> > Can you print out its blkaddr?
> >
> > If possible, could you print out:
> >   curseg->segno, curseg->next_blkoff,a curseg->next_segno
> >   at the end of allocate_segment_by_default()?
> 
> Thank you for the help!
> Here are the new traces:

Thank you.

> 
> [   49.274678] ------------[ cut here ]------------
> [   49.280216] WARNING: at /home/alex/work/s2l/amb_S2l_SDK_2.5/SDK2.5/s2l_linux_sdk/ambarella/kernel/linux-3.10/fs/f2fs/segment.c:1105 new_curseg+0x268/0x394 [f2fs]()

This means there is no free segment.
Could you print out the below information before this f2fs_bug_on?
- prefree_segments(sbi)
- free_segments(sbi)

> ...
> [   49.518054] ---[ end trace 49dca462b4f988ff ]---
> [   49.522689] ------------[ cut here ]------------
> [   49.527375] WARNING: at /home/alex/work/s2l/amb_S2l_SDK_2.5/SDK2.5/s2l_linux_sdk/ambarella/kernel/linux-3.10/fs/f2fs/segment.c:1144 new_curseg+0x2f0/0x394 [f2fs]()

This is caused by the above segno which was -1.

> ...
> [   49.764853] ---[ end trace 49dca462b4f98900 ]---
> [   49.857344] ------ segno = 7540, next_blkoff = 0, next_segno = 4294967295 --------
> [   49.913664] ------ blkaddr = 3889152 --------
> [   49.918173] Unable to handle kernel NULL pointer dereference at virtual address 00000000

Also, we can see next_segno was -1, which incur no se entry for this segment.
At this moment, I'd really like to see its /sys/kernel/debug/f2fs/status whether
there is really not enough free segments.

Thanks,

> ...
> 
> -- 
>  Alexander

------------------------------------------------------------------------------