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Date:   Wed, 12 May 2021 13:45:25 +0000
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     David Howells <dhowells@redhat.com>
Cc:     Dominique Martinet <asmadeus@codewreck.org>,
        Luis Henriques <lhenriques@suse.de>,
        Eric Van Hensbergen <ericvh@gmail.com>,
        Latchesar Ionkov <lucho@ionkov.net>,
        linux-fsdevel@vger.kernel.org, v9fs-developer@lists.sourceforge.net
Subject: Re: What sort of inode state does ->evict_inode() expect to see?
 [was Re: 9p: fscache duplicate cookie]
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On Wed, May 12, 2021 at 01:57:11PM +0100, David Howells wrote:
> Hi Al,
> 
> We're seeing cases where fscache is reporting cookie collisions that appears
> to be due to ->evict_inode() running parallel with a new inode for the same
> filesystem object getting set up.

Huh?  Details, please.  What we are guaranteed is that iget{,5}_locked() et.al.
on the same object will either prevent the call of ->evict_inode() (if they
manage to grab the sucker before I_FREEING is set) or will wait until after
->evict_inode() returns.