rsync + hammer + nfs = trouble

[Aggelos Economopoulos]

On Monday 14 July 2008, Matthew Dillon wrote:
> 
> :> :Aggelos
> :> 
> :>     It sounds like a buffer cache deadlock, which should be easy for me to
> :>     fix.  Were you reading from the NFS mount or writing to the NFS mount?
> :
> :Only rsync (via nfs) was accessing the filesystem.
> :
> :>     I'm assuming you are running the latest HEAD.  If so, please drop
> :>     into the debugger (e.g. ctl-alt-esc) and generate a crash dump, and
> :>     get it onto leaf so I can take a look.
> :
> :I am running HEAD from ~28h ago. Unfortunately, IIRC the machine doesn't have
> :a dumpdev configured (yeah, I know). Is there any information I can get you
> :via DDB?
[...]
>     Try it with latest head, to make sure the bug is still there.

Sure.

>     I need to know whether rdist was reading HAMMER via NFS or writing to
>     HAMMER via NFS, and what kinds of file structure was being copied?
>     (big files, little files, hundreds of files, thousands of files.. what?).

Just an rsync -av src dst, where dst is the nfs-mounted hammer volume, which
was just created, so I don't think rsync could read much. It got stuck in
the devel/ directory (in an old dragonfly sys/ checkout even). The file was
some version of ibcs2_stat.c. Before getting there it had copied over a few
hundread thousands of files, some small, some average-sized. I'm going to
make sure I can get a dump and then try it with latest head.

Aggelos