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()?
--
Trond Myklebust
Linux NFS client maintainer, PrimaryData
trond.myklebust@xxxxxxxxxxxxxxx
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