[linux-lvm] Re: Problems running my home-built LVM2

[Stefan Monnier <monnier iro umontreal ca>]

>> _io in dev-io.c) would often return garbage (tho not always).  Not sure
>> if it's a problem in LVM2, or in uClibc, or in the kernel, but I think
>> I've already wasted more than enough time on this, so I'll just use
>> the --disable-o_direct workaround.
> We had a problem with O-direct several years ago which we blamed on a rogue
> version of gcc.

Based on my experience I'd say that it seems to still be around.
At least on `mipsel'.  I have since discovered that Debian's `lvm2'
package disables O_DIRECT with the following lines:

   ifneq (,$(findstring $(DEB_HOST_ARCH), arm armeb hppa mips mipsel))
   CONFIGURE_FLAGS += --disable-o_direct
   endif

so that's probably why the Debian package worked fine.  It's probably
unrelated to uClibc.  My wild gut feeling is that it's a bug in the
kernel's handling of cache coherency.

Related Debian bugs are #351632 #330166 #267157 #247896.


        Stefan