Re: [PATCH 2/5] NFS: Request a directory delegation on ACCESS, CREATE, and UNLINK

[Jon Hunter <jonathanh@nvidia.com>]

Hi Trond,

On 03/12/2025 16:23, Trond Myklebust wrote:
> Hi Jon,
> 
> On Wed, 2025-12-03 at 15:56 +0000, Jon Hunter wrote:
>>
>> On 02/12/2025 16:01, Jon Hunter wrote:
>>> Hi Anna,
>>>
>>> On 04/11/2025 15:06, Anna Schumaker wrote:
>>>> From: Anna Schumaker <anna.schumaker@oracle.com>
>>>>
>>>> This patch adds a new flag: NFS_INO_REQ_DIR_DELEG to signal that
>>>> a
>>>> directory wants to request a directory delegation the next time
>>>> it does
>>>> a GETATTR. I have the client request a directory delegation when
>>>> doing
>>>> an access, create, or unlink call since these calls indicate that
>>>> a user
>>>> is working with a directory.
>>>>
>>>> Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
>>>
>>>
>>> We use NFS for boot testing our boards and once this commit landed
>>> in -
>>> next a lot of them, but no all, started failing to boot. Bisect is
>>> pointing to this change.
>>>
>>> We have a custom init script that runs to mount the rootfs and I
>>> see
>>> that it displays ...
>>>
>>> [   10.238091] Run /init as init process
>>> [   10.266026] ERROR: mounting debugfs fail...
>>> [   10.286535] Root device found: nfs
>>> [   10.300342] Ethernet interface: eth0
>>> [   10.313920] IP Address: 192.168.99.2
>>> [   10.382738] Rootfs mounted over nfs
>>> [   10.416010] Switching from initrd to actual rootfs
>>
>> It appears that there are multiple boot issues on -next at the moment
>> and the above it not the relevant part for this particular issue.
>> Looking further at the logs I am seeing the following errors which
>> are related to this change ...
>>
>> [   11.100334] systemd[1]: Failed to open directory
>> /etc/systemd/system, ignoring: Unknown error 524
>> [   11.119234] systemd[1]: Failed to open directory
>> /lib/systemd/system, ignoring: Unknown error 524
>> [   11.143487] systemd[1]: Failed to load default target: No such
>> file or directory
>> [   11.158620] systemd[1]: Trying to load rescue target...
>> [   11.169388] systemd[1]: Failed to load rescue target: No such file
>> or directory
>> [   11.188856] systemd[1]: Freezing execution.
>>
>> Thanks
>> Jon
> 
> Does the following patch fix it for you?
> 
> 8<---------------------------------------------
>  From 849bdbd3a2136a86c809ce6a7fa6ae30e9f0728a Mon Sep 17 00:00:00 2001
> Message-ID: <849bdbd3a2136a86c809ce6a7fa6ae30e9f0728a.1764778907.git.trond.myklebust@hammerspace.com>
> From: Trond Myklebust <trond.myklebust@hammerspace.com>
> Date: Wed, 3 Dec 2025 11:17:25 -0500
> Subject: [PATCH] NFSv4: Handle NFS4ERR_NOTSUPP errors for directory
>   delegations
> 
> The error NFS4ERR_NOTSUPP will be returned for operations that are
> legal, but not supported by the server.
> 
> Fixes: 156b09482933 ("NFS: Request a directory delegation on ACCESS, CREATE, and UNLINK")
> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
> ---
>   fs/nfs/nfs4proc.c | 25 +++++++++++++++++--------
>   1 file changed, 17 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index c53ddb185aa3..ec1ce593dea2 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -4533,12 +4533,17 @@ static int _nfs4_proc_getattr(struct nfs_server *server, struct nfs_fh *fhandle,
>   	status = nfs4_do_call_sync(server->client, server, &msg,
>   				   &args.seq_args, &res.seq_res, task_flags);
>   	if (args.get_dir_deleg) {
> -		if (status == -EOPNOTSUPP) {
> +		switch (status) {
> +		case 0:
> +			if (gdd_res.status != GDD4_OK)
> +				break;
> +			status = nfs_inode_set_delegation(
> +				inode, current_cred(), FMODE_READ,
> +				&gdd_res.deleg, 0, NFS4_OPEN_DELEGATE_READ);
> +			break;
> +		case -ENOTSUPP:
> +		case -EOPNOTSUPP:
>   			server->caps &= ~NFS_CAP_DIR_DELEG;
> -		} else if (status == 0 && gdd_res.status == GDD4_OK) {
> -			status = nfs_inode_set_delegation(inode, current_cred(),
> -							  FMODE_READ, &gdd_res.deleg,
> -							  0, NFS4_OPEN_DELEGATE_READ);
>   		}
>   	}
>   	return status;
> @@ -4554,10 +4559,14 @@ int nfs4_proc_getattr(struct nfs_server *server, struct nfs_fh *fhandle,
>   	do {
>   		err = _nfs4_proc_getattr(server, fhandle, fattr, inode);
>   		trace_nfs4_getattr(server, fhandle, fattr, err);
> -		if (err == -EOPNOTSUPP)
> -			exception.retry = true;
> -		else
> +		switch (err) {
> +		default:
>   			err = nfs4_handle_exception(server, err, &exception);
> +			break;
> +		case -ENOTSUPP:
> +		case -EOPNOTSUPP:
> +			exception.retry = true;
> +		}
>   	} while (exception.retry);
>   	return err;
>   }

Yes that does appear to fix it thanks!

Cheers
Jon

-- 
nvpublic