Re: kern/38892: msdosfs panic

[Tom Spindler <dogcow%babymeat.com@localhost>]

The following reply was made to PR kern/38892; it has been noted by GNATS.

From: Tom Spindler <dogcow%babymeat.com@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: kern-bug-people%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost, 
hannken%netbsd.org@localhost
Subject: Re: kern/38892: msdosfs panic
Date: Tue, 17 Jun 2008 01:17:32 -0700

 To summarize the current state of investigation, AFAICT:
 <20080616155344.GA5467%aardappel.13thmonkey.org@localhost> on tech-kern
 points out that the getblk() semantics changed so that it's possible
 for it to return NULL. (This change was made around Jan-Feb by ad.)
 
 Around 15 May, hannken made a bunch of changes to msdosfs and friends
 to change the semantics of bread; at that time, sys/kern/vfs_bio.c was
 also changed to add a bunch of KASSERT()s. One of the asserts is the
        bp->b_vp == NULL || bp->b_vp->v_tag != VT_UFS ||
            ISSET(bp->b_flags, B_COWDONE)
 one that's actually causing the panics. Why UFS gets special treatment,
 I don't know.