Re: VOP_WRITE without vnode lock

[David Holland <dholland-tech%netbsd.org@localhost>]

On Thu, Aug 07, 2008 at 11:35:24AM +0200, Juergen Hannken-Illjes wrote:
 > Is it safe (regarding data consistency) to VOP_WRITE() to a vnode
 > without holding the vnode lock when:
 > 
 > - The write is always a full size block. 
 > - A block gets only written once and writes are serialized.
 > - No others are allowed to write the vnode. 
 > - Data written is always the same that would have been read before.

It seems like a bad idea; even if it works now it's the kind of thing
that will blow up mysteriously four years down the road. So I'd avoid
it if reasonably possible.

Also the VOP_* wrappers check for the lock being held properly; you'd
have to circumvent that somehow and that seems unwise too.

-- 
David A. Holland
dholland%netbsd.org@localhost