Re: 2.6.9-mm1: LVM stopped working (dio-handle-eof.patch)

[jfannin1@columbus.rr.com]

On Tue, Oct 26, 2004 at 02:59:55PM +0100, Alasdair G Kergon wrote:
> On Tue, Oct 26, 2004 at 08:36:51AM -0400, jfannin1@columbus.rr.com wrote:
> > LVM doesn't work with 2.6.9-mm1 here either, complaining that it
> > can't find all the pv's. I'm not using any sort of encryption. Here,
> > pvdisplay reports:
> 
> > I can open the device nodes for the 'missing' pv's in a hexeditor and see the
> > uuid magic; if I reboot into 2.6.9-rc4-mm1 they are found without a
> > problem, and everything works.

> [To check for repeat of old problems with related symptoms:]
>   Were both kernels compiled with the same compiler version? Which version?
>   Does it make any difference if you rebuild lvm with --disable-o_direct?

    Chris Han (BCC'ed) mailed me to let me know he'd narrowed the
problem down to the 'dio-handle-eof.patch'.  Reverting it makes things
work for me too.  Yay!

> Firstly enable lvm debugging.  lvm.conf: log { file="/tmp/lvm2.log" level=7 }
> Compare the lvm log files for the kernels to see where it's going wrong.
> Then take complete straces (incl. read/write data) of the lvm process 
> with each kernel and again compare them. [Or put files on web and send URLs.]

vgchange -a y logs that it 'Failed to read label area' for the
'missing' pv's.

I've put up some possibly useful traces, but I think I've picked out
the relevant bits just below:
http://home.columbus.rr.com/jfannin1/vgchange-trace-good.txt
http://home.columbus.rr.com/jfannin1/vgchange-trace-bad.txt

Some (but not all) partitions opened are reading alternately (the -1024 is
constant): 

read(4, 0xbfffe600, 2048)               = ? ERESTARTSYS (To be restarted)
read(4, "\300;9\230", 2048)             = -1024

    If there's anything else that wants investigating, I'm still
willing as my free time allows.  Thanks!

-- 
Joseph Fannin
jfannin1@columbus.rr.com