On Thu, 5 Jun 2014 12:18:09 -0400
Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> wrote:
> On Thu, Jun 5, 2014 at 12:12 PM, J. Bruce Fields <bfields@xxxxxxxxxxxx> wrote:
> > On Fri, May 30, 2014 at 09:09:32AM -0400, Jeff Layton wrote:
> >> From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
> >>
> >> Ensure that we only can have a single struct nfs4_file per inode
> >> in the file_hashtbl and make addition atomic with respect to lookup.
> >>
> >> Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
> >> ---
> >> fs/nfsd/nfs4state.c | 46 +++++++++++++++++++++++++++++++++++-----------
> >> 1 file changed, 35 insertions(+), 11 deletions(-)
> >>
> >> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> >> index a500033a2f87..553c2d6d48dc 100644
> >> --- a/fs/nfsd/nfs4state.c
> >> +++ b/fs/nfsd/nfs4state.c
> >> @@ -2519,6 +2519,8 @@ static void nfsd4_init_file(struct nfs4_file *fp, struct inode *ino)
> >> {
> >> unsigned int hashval = file_hashval(ino);
> >>
> >> + lockdep_assert_held(&state_lock);
> >> +
> >
> > Oops, lockdep points out we overlooked a deadlock here: this function
> > also calls igrab(), which takes the i_lock, the reverse ordering from
> > what we take in the delegation-break case.
> >
> > Dropping this patch for now.
> >
>
> This was the reason for the delegation recall locking changes which
> are also part of the series.
>
> That said, why do we need igrab here as opposed to just ihold()?
>
Yeah, that would be a lot simpler. We certainly already have a
reference by virtue of the dentry in the filehandle so ihold is
reasonable. I'll change it to use that.
--
Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
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