> On Aug 24, 2020, at 10:22 AM, Bruce Fields <bfields@xxxxxxxxxxxx> wrote:
>
> On Mon, Aug 24, 2020 at 09:39:31AM -0400, Chuck Lever wrote:
>>
>>
>>> On Aug 19, 2020, at 5:29 PM, Bruce Fields <bfields@xxxxxxxxxxxx> wrote:
>>>
>>> On Tue, Aug 18, 2020 at 05:26:26PM -0400, Chuck Lever wrote:
>>>>
>>>>> On Aug 17, 2020, at 6:20 PM, Bruce Fields <bfields@xxxxxxxxxxxx> wrote:
>>>>>
>>>>> On Sun, Aug 16, 2020 at 04:46:00PM -0400, Chuck Lever wrote:
>>>>>
>>>>>> In order of application:
>>>>>>
>>>>>> 5920afa3c85f ("nfsd: hook nfsd_commit up to the nfsd_file cache")
>>>>>> 961.68user 5252.40system 20:12.30elapsed 512%CPU, 2541 DELAY errors
>>>>>> These results are similar to v5.3.
>>>>>>
>>>>>> fd4f83fd7dfb ("nfsd: convert nfs4_file->fi_fds array to use nfsd_files")
>>>>>> Does not build
>>>>>>
>>>>>> eb82dd393744 ("nfsd: convert fi_deleg_file and ls_file fields to nfsd_file")
>>>>>> 966.92user 5425.47system 33:52.79elapsed 314%CPU, 1330 DELAY errors
>>>>>>
>>>>>> Can you take a look and see if there's anything obvious?
>>>>>
>>>>> Unfortunately nothing about the file cache code is very obvious to me.
>>>>> I'm looking at it....
>>>>>
>>>>> It adds some new nfserr_jukebox returns in nfsd_file_acquire. Those
>>>>> mostly look like kmalloc failures, the one I'm not sure about is the
>>>>> NFSD_FILE_HASHED check.
>>>>>
>>>>> Or maybe it's the lease break there.
>>>>
>>>> nfsd_file_acquire() always calls fh_verify() before it invokes nfsd_open().
>>>> Replacing nfs4_get_vfs_file's nfsd_open() call with nfsd_file_acquire() adds
>>>> almost 10 million fh_verify() calls to my test run.
>>>
>>> Checking out the code as of fd4f83fd7dfb....
>>>
>>> nfsd_file_acquire() calls nfsd_open_verified().
>>>
>>> And nfsd_open() is basically just fh_verify()+nfsd_open_verified().
>>>
>>> So it doesn't look like the replacement of nfsd_open() by
>>> nfsd_file_acquire() should have changed the number of fh_verify() calls.
>>
>> I see a lot more vfs_setlease() failures after fd4f83fd7dfb.
>> check_conflicting_open() fails because "inode is open for write":
>>
>> 1780 if (arg == F_RDLCK)
>> 1781 return inode_is_open_for_write(inode) ? -EAGAIN : 0;
>>
>> The behavior on the wire is that the server simply doesn't hand out
>> many delegations.
>>
>> NFSv4 OPEN uses nfsd_file_acquire() now, but I don't see CLOSE
>> releasing the cached file descriptor. Wouldn't that cached
>> descriptor conflict with subsequent OPENs?
>
> Could be, yes.
>
> That also reminds me of this patch, did I already send it to you?
I don't have this one. I can try it.
> --b.
>
> commit 055e7b94ef32
> Author: J. Bruce Fields <bfields@xxxxxxxxxx>
> Date: Fri Jul 17 18:54:54 2020 -0400
>
> nfsd: Cache R, RW, and W opens separately
>
> The nfsd open code has always kept separate read-only, read-write, and
> write-only opens as necessary to ensure that when a client closes or
> downgrades, we don't retain more access than necessary.
>
> Honestly, I'm not sure if that's completely necessary, but I'd rather
> stick to that behavior.
>
> Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
>
> diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
> index 82198d747c4c..4b6f70e0d987 100644
> --- a/fs/nfsd/filecache.c
> +++ b/fs/nfsd/filecache.c
> @@ -891,7 +891,7 @@ nfsd_file_find_locked(struct inode *inode, unsigned int may_flags,
>
> hlist_for_each_entry_rcu(nf, &nfsd_file_hashtbl[hashval].nfb_head,
> nf_node, lockdep_is_held(&nfsd_file_hashtbl[hashval].nfb_lock)) {
> - if ((need & nf->nf_may) != need)
> + if (nf->nf_may != need)
> continue;
> if (nf->nf_inode != inode)
> continue;
--
Chuck Lever
