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Re: NFS lockup after UDP fragments getting lost (was: 8.1 tstile lockup after nfs send error 51)

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


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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