BUG() in end_page_writeback(), stack overflows and system speed decrease with XFS over USB
sandeen at sandeen.net
Fri Nov 20 10:36:31 CST 2009
Juergen Urban wrote:
> On Thursday 19 November 2009 19:00:16 Eric Sandeen wrote:
>> Juergen Urban wrote:
>>> my machine is running very unstable since I use XFS on an external USB
>>> harddisc (855 GByte XFS partition on 1TByte). One problem was the stack
>>> overflows caused by the large stack use of XFS, USB, SCSI and VFS in
>>> Linux 184.108.40.206. NFS on XFS caused much more stack overflows. I think I
>>> got around the stack overflows by disabling preemption, SMP and NFS in
>>> Linux, but I am not sure about it. I think that I didn't got a message
>>> from the stack overflow detection after this.
>> Are you on 4k stacks? To be honest I'd still expect things to be mostly
>> ok stack-wise even if so.
> No, I am using 8k stacks.
> Now I tried linux-220.127.116.11. My system hangs in the start scripts. Maybe this
> is caused by network scripts. I got the message that ehci_hcd need to be
> loaded before uhci_hcd and ohci_hcd. I skipped uhci_hcd and ohci_hcd in
> /etc/discover.conf. Now I have a higher performance with linux-18.104.22.168 and I
> can record 3 normal streams in parallel on the with USB and XFS. But it is
> still unstable. The last error what I got was in block_prepare_write
> (fs/buffer.c). This caused follow up errors in do_invalidate_page() called by
> Sometimes there are file system deadlocks. I can do everything, but not access
> the file system. Every try to access the file system leads to a deadlock of the
> program. This normally happens after a kernel exception.
I guess including the kernel messages you see would help us know what
might be going on.
>>> Is there an easy way to backup the data or replace the file system
>>> without kernel crash in between?
>> You should certainly be able to copy data off xfs via usb; if it's
>> failing, I guess we'll need more info to find out why, but I'd suggest
>> at least booting a newer livecd to do that copy and see if things fare
> My idea was to shrink it and create a new partition where I can copy the data.
> As far as I understand I need to mount it for the shrink process, so I may
> have the problem of kernel exceptions while shrinking.
You can't shrink xfs, if that's what you mean.
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