> On Jul 31, 2019, at 1:45 AM, Edgar Fuß <[email protected]> wrote:
> 
> NetBSD design error (or so Taylor says) that a vnode lock may be held accross 
> I/O

100%

NetBSD's VFS locking protocol needs a serious overhaul.  At least one other 
BSD-family VFS (the one in XNU) completely eliminated locking of vnodes at the 
VFS layer (it's all pushed into the file system back-ends who now have more 
control over their own locking requirements).  It does have some additional 
complexities around reference / busy counting and vnode identity, but it works 
very well in practice.

I don't know what FreeBSD has done in this area.

-- thorpej

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