Re: Processes blocked on ufs or getblk

On Thu, 15 Jan 2004, Lachlan O'Dea wrote:

> -----BEGIN PGP SIGNED MESSAGE-----
>
> I found some discussion about this in December, but I don't think
> anyone has been able to get to the bottom of it yet. The symptom is
> that processes become permanently blocked in a state of ufs or getblk.
> I can reproduce it with find at will:
>
> % ps axl | grep ufs
>      0 13225 13215   1  -4  0  1300  804 ufs    D     ??    0:00.96 find
> /var -xdev -type f ( -perm -u+x -or -perm -g+x -or -perm -o+
>      0 28778 28765   0  -4  0  1300  804 ufs    D     ??    0:00.97 find
> /var -xdev -type f ( -perm -u+x -or -perm -g+x -or -perm -o+
>      0 33017 32933   2  -4  0  1304  788 ufs    D     p2-   0:10.69 find
> / -name samba
>
> It has also happened several times in single user mode to makewhatis
> running at the end of installworld.
>
> System details: 5.2-RC FreeBSD 5.2-RC #1: Fri Jan  9 04:45:51 EST 2004.
> Dell PowerEdge 2500. All filesystems are on a single raid 5 volume
> using the aac driver. The box has two CPUs, but I'm currently running
> with kern.smp.disabled=1.
>
> % mount
> /dev/aacd0s1a on / (ufs, local)
> devfs on /dev (devfs, local)
> /dev/aacd0s1e on /usr (ufs, local, with quotas, soft-updates)
> /dev/aacd0s1d on /var (ufs, local, soft-updates)
> procfs on /proc (procfs, local)
> linprocfs on /usr/compat/linux/proc (linprocfs, local)
>
> I also have ACLs enabled on /usr, if that's at all relevant.
>
> The kernel has DDB and DEBUG_LOCKS. Please let me know if there's
> anything I can do to help debug this.
>
> I don't know if this is related, but another problem is that when
> shutting down, it always gives up on a bunch of buffers. I think I've
> seen over 100, but usually it's 4-10 buffers.

I'm seeing the same thing on my desktop machine. It usually occurs while
scanning large directories and/or dealing with large collections of files
rather quickly. I came across this bug while using gqview to go through my
image collection and a second time while re-checking out my ports tree
from local cvs. The programs appear to grab an exclusive lock and anything
that tries to read or write to the directory (or get a directory listing)
gets stuck in ufs state.

My kernel config is rather simple, GENERIC without a lot of cruft except
amr, ata, scsi, usb and pcm. I'll try to get the output of a ddb ps and a
show lockedvnods.

The system in question is:
FreeBSD bling.home 5.2-CURRENT FreeBSD 5.2-CURRENT #5: Tue Jan  6 22:32:09
EST 2004     root_at_bling.home:/usr/src/sys/i386/compile/BLING  i386

I'm currently recompiling my kernel to see if this behavior is still
around in newer CURRENT.

Regards,

> Andre Guibert de Bruet | Enterprise Software Consultant >
> Silicon Landmark, LLC. | http://siliconlandmark.com/    >