Date: Mon, 4 Aug 2008 17:04:58 -0400 (EDT) From: Rick Macklem <rmacklem@uoguelph.ca> To: freebsd-fs@freebsd.org Subject: doing vfs_hash_get when vnode locked Message-ID: <Pine.GSO.4.63.0808041657200.3482@muncher.cs.uoguelph.ca>
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There's a place in my nfsv4 client where I need to vfs_hash_get() when another blocked thread may be holding a lock on the vnode. (It's during a recovery case where the other threads are blocked, so there isn't a race problem, as far as I understand it.) For FreeBSD7, all I did was call vfs_hash_get() with flags == 0 and it gave me what I wanted (the vnode for the file handle with a reference count, but no lock). For FreeBSD-CURRENT/8, this no longer works, because vfs_hash_get() calls vget(), which calls _vn_lock() and _vn_lock() now complains if the lock type field of "flags" is 0. I came up with a really ugly workaround, by setting the flags arg. to LK_EXCLOTHER for vfs_hash_get() and then providing my own VOP_LOCK1() which just VI_UNLOCK()s and returns 0 for this case (doing the same as vop_stdlock() for other cases). Yuck!! Is it possible to re-enable the case of _vn_lock() getting a locktype field == 0 (or defining one that says "just return 0 unless VI_DOOMED"), so I don't need the dirty hack? Have a good week, rick
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