Re: Weirdness when writing to pseudofs file

From: Johannes Lundberg <johalun_at_FreeBSD.org>
Date: Wed, 22 May 2019 16:12:19 -0700
On 5/22/19 3:02 PM, Conrad Meyer wrote:
> On Wed, May 22, 2019 at 1:58 PM Johannes Lundberg <johalun_at_freebsd.org> wrote:
>>> It seems, a single '>' will cause it to try to create the file (even
>>> though it already exists) and that fails (kern_openat).
>>>
>> I would guess because of
>>
>> https://github.com/freebsd/freebsd/blob/master/sys/fs/pseudofs/pseudofs_vnops.c#L1042
>>
>> struct vop_vector pfs_vnodeops = {
>> ...
>> .vop_create = VOP_EOPNOTSUPP,
>> ...
>> }
> kern_openat -> vn_open(_cred) should only call VOP_CREATE if namei()
> cannot find the named vnode (ni_vp == NULL).  Otherwise, it should
> just invoke VOP_OPEN.  This suggests there might be a lookup bug in
> pfs?  Tracing VOPs as Mark suggested seems like a good next step.
>
> Best,
> Conrad

Thanks Conrad. Yeah, that makes sense that it would open instead of
recreating. Tracing a'la Mark points to

vop_getwritemount

failing.
Received on Wed May 22 2019 - 21:12:22 UTC

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