[OpenAFS-devel] AFS and UFS logging (fwd)

[Quanah Gibson-Mount]

Does anyone know if this particular problem has been fixed inside of 
OpenAFS?  We are looking at using ufs logging, but will keep it off of the 
AFS cache location until it is know if this if fixed.

--Quanah


---------- Forwarded Message ----------
Date: Friday, June 14, 2002 11:05 AM -0700
From: Jim Stosick <jws@lindy.stanford.edu>
To: Quanah Gibson-Mount <quanah@Stanford.EDU>
Subject: AFS and UFS logging

This is the note that I got from Sun about the problem with putting
the AFS cache on a file system with UFS logging enabled.  This was
the diagnosis from a dump we sent to Sun.

-------- Original Message --------
Subject: case 62699913) STANFORD UNIVER, (Bug# 4506059)]
Date: Wed, 21 Nov 2001 10:58:29 -0700
From: john harres <john.harres@Sun.COM>
Organization: Sun Microsystems
To: jws@Stanford.EDU

Sorry it took so long to get this paragraph put together.  Here is a
description of why AFS's usage of logging UFS (lufs) causes a system
hang:


A ufs_write starts a transaction and generates a page_fault through
VOP_GETPAGE() which becomes afs_getpage.  afs_getpage decides to
truncate the file, but also then calls ufs_setattr, generating a second
transaction.  Due to how these two transactions are stacked, and with a
specific timing of fsflush actions generates a deadlock.

---------- End Forwarded Message ----------