kern/85503: panic: wrong dirclust using msdosfs in RELENG_6

[Dmitry Pryanishnikov]

The following reply was made to PR kern/85503; it has been noted by GNATS.

From: Dmitry Pryanishnikov <dmitry at atlantis.dp.ua>
To: Poul-Henning Kamp <phk at haven.freebsd.dk>
Cc: freebsd-arch at freebsd.org, bug-followup at freebsd.org
Subject: Re: kern/85503: panic: wrong dirclust using msdosfs in RELENG_6 
Date: Mon, 5 Sep 2005 13:50:01 +0300 (EEST)

 Hello!
 
 On Fri, 2 Sep 2005, Poul-Henning Kamp wrote:
 >> found the primary error (lack of casts leaded to 32-bit result), but then
 >> we should transfer this 64-bit "inode" number to vfs_hash_get(). Oops,
 >> it also limited to u_int (32 bits on i386). Finally, I see that the
 >> primary shortcoming here: in sys/vnode.h we have
 >
 > NFS has the same sort of problem, it has 16 or 32 *bytes* filehandles
 > that need to hash to 32 bit "inode numbers".
 >
 > If you look at vfs_hash_get calls in sys/nfsclient you can see that
 > it calculates a 32bit hash but then provides a "nfs_vncmpf" function
 > to do the actual comparison to resolve hash collisions.
 
   Indeed, I've missed last 2 arguments of vfs_hash_get(). Actually it seems
 that the only error here is missing cast. After application of the following
 patch:
 
  	ftp://external.atlantis.dp.ua/FreeBSD/PR/85503/msdosfs.patch
 
 problem has gone away. Please, if possible, review and commit it. I think this
 patch is a good MFC candidate for RELENG_6 and RELENG_6_0, since it prevents 
 panic in quite common environment.
 
 Sincerely, Dmitry
 -- 
 Atlantis ISP, System Administrator
 e-mail:  dmitry at atlantis.dp.ua
 nic-hdl: LYNX-RIPE