diff mbox series

[v4,01/11] nfsd: fix initial getattr on write delegation

Message ID 20240905-delstid-v4-1-d3e5fd34d107@kernel.org (mailing list archive)
State New
Headers show
Series nfsd: implement the "delstid" draft | expand

Commit Message

Jeff Layton Sept. 5, 2024, 12:41 p.m. UTC
At this point in compound processing, currentfh refers to the parent of
the file, not the file itself. Get the correct dentry from the delegation
stateid instead.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/nfsd/nfs4state.c | 31 +++++++++++++++++++++++--------
 1 file changed, 23 insertions(+), 8 deletions(-)

Comments

Chuck Lever III Sept. 5, 2024, 3:46 p.m. UTC | #1
On Thu, Sep 05, 2024 at 08:41:45AM -0400, Jeff Layton wrote:
> At this point in compound processing, currentfh refers to the parent of
> the file, not the file itself. Get the correct dentry from the delegation
> stateid instead.
> 
> Signed-off-by: Jeff Layton <jlayton@kernel.org>

Subject says "fixes ..." so IMO a Fixes: tag is warranted.
Suggestions welcome.


> ---
>  fs/nfsd/nfs4state.c | 31 +++++++++++++++++++++++--------
>  1 file changed, 23 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index df69dc6af467..db90677fc016 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -5914,6 +5914,26 @@ static void nfsd4_open_deleg_none_ext(struct nfsd4_open *open, int status)
>  	}
>  }
>  
> +static bool
> +nfs4_delegation_stat(struct nfs4_delegation *dp, struct svc_fh *currentfh,
> +		     struct kstat *stat)
> +{
> +	struct nfsd_file *nf = find_rw_file(dp->dl_stid.sc_file);
> +	struct path path;
> +
> +	if (!nf)
> +		return false;
> +
> +	path.mnt = currentfh->fh_export->ex_path.mnt;
> +	path.dentry = file_dentry(nf->nf_file);
> +
> +	if (vfs_getattr(&path, stat,
> +			(STATX_INO | STATX_SIZE | STATX_CTIME | STATX_CHANGE_COOKIE),
> +			AT_STATX_SYNC_AS_STAT))
> +		return false;
> +	return true;
> +}
> +
>  /*
>   * The Linux NFS server does not offer write delegations to NFSv4.0
>   * clients in order to avoid conflicts between write delegations and
> @@ -5949,7 +5969,6 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
>  	int cb_up;
>  	int status = 0;
>  	struct kstat stat;
> -	struct path path;
>  
>  	cb_up = nfsd4_cb_channel_good(oo->oo_owner.so_client);
>  	open->op_recall = false;
> @@ -5985,20 +6004,16 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
>  	memcpy(&open->op_delegate_stateid, &dp->dl_stid.sc_stateid, sizeof(dp->dl_stid.sc_stateid));
>  
>  	if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE) {
> -		open->op_delegate_type = NFS4_OPEN_DELEGATE_WRITE;
> -		trace_nfsd_deleg_write(&dp->dl_stid.sc_stateid);
> -		path.mnt = currentfh->fh_export->ex_path.mnt;
> -		path.dentry = currentfh->fh_dentry;
> -		if (vfs_getattr(&path, &stat,
> -				(STATX_SIZE | STATX_CTIME | STATX_CHANGE_COOKIE),
> -				AT_STATX_SYNC_AS_STAT)) {
> +		if (!nfs4_delegation_stat(dp, currentfh, &stat)) {
>  			nfs4_put_stid(&dp->dl_stid);
>  			destroy_delegation(dp);
>  			goto out_no_deleg;
>  		}
> +		open->op_delegate_type = NFS4_OPEN_DELEGATE_WRITE;
>  		dp->dl_cb_fattr.ncf_cur_fsize = stat.size;
>  		dp->dl_cb_fattr.ncf_initial_cinfo =
>  			nfsd4_change_attribute(&stat, d_inode(currentfh->fh_dentry));
> +		trace_nfsd_deleg_write(&dp->dl_stid.sc_stateid);
>  	} else {
>  		open->op_delegate_type = NFS4_OPEN_DELEGATE_READ;
>  		trace_nfsd_deleg_read(&dp->dl_stid.sc_stateid);
> 
> -- 
> 2.46.0
>
Jeff Layton Sept. 5, 2024, 5:37 p.m. UTC | #2
On Thu, 2024-09-05 at 11:46 -0400, Chuck Lever wrote:
> On Thu, Sep 05, 2024 at 08:41:45AM -0400, Jeff Layton wrote:
> > At this point in compound processing, currentfh refers to the parent of
> > the file, not the file itself. Get the correct dentry from the delegation
> > stateid instead.
> > 
> > Signed-off-by: Jeff Layton <jlayton@kernel.org>
> 
> Subject says "fixes ..." so IMO a Fixes: tag is warranted.
> Suggestions welcome.
> 
> 

Yes, sorry. I think we want:

Fixes: c5967721e106 ("NFSD: handle GETATTR conflict with write delegation")

> > ---
> >  fs/nfsd/nfs4state.c | 31 +++++++++++++++++++++++--------
> >  1 file changed, 23 insertions(+), 8 deletions(-)
> > 
> > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> > index df69dc6af467..db90677fc016 100644
> > --- a/fs/nfsd/nfs4state.c
> > +++ b/fs/nfsd/nfs4state.c
> > @@ -5914,6 +5914,26 @@ static void nfsd4_open_deleg_none_ext(struct nfsd4_open *open, int status)
> >  	}
> >  }
> >  
> > +static bool
> > +nfs4_delegation_stat(struct nfs4_delegation *dp, struct svc_fh *currentfh,
> > +		     struct kstat *stat)
> > +{
> > +	struct nfsd_file *nf = find_rw_file(dp->dl_stid.sc_file);
> > +	struct path path;
> > +
> > +	if (!nf)
> > +		return false;
> > +
> > +	path.mnt = currentfh->fh_export->ex_path.mnt;
> > +	path.dentry = file_dentry(nf->nf_file);
> > +
> > +	if (vfs_getattr(&path, stat,
> > +			(STATX_INO | STATX_SIZE | STATX_CTIME | STATX_CHANGE_COOKIE),
> > +			AT_STATX_SYNC_AS_STAT))
> > +		return false;
> > +	return true;
> > +}
> > +
> >  /*
> >   * The Linux NFS server does not offer write delegations to NFSv4.0
> >   * clients in order to avoid conflicts between write delegations and
> > @@ -5949,7 +5969,6 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
> >  	int cb_up;
> >  	int status = 0;
> >  	struct kstat stat;
> > -	struct path path;
> >  
> >  	cb_up = nfsd4_cb_channel_good(oo->oo_owner.so_client);
> >  	open->op_recall = false;
> > @@ -5985,20 +6004,16 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
> >  	memcpy(&open->op_delegate_stateid, &dp->dl_stid.sc_stateid, sizeof(dp->dl_stid.sc_stateid));
> >  
> >  	if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE) {
> > -		open->op_delegate_type = NFS4_OPEN_DELEGATE_WRITE;
> > -		trace_nfsd_deleg_write(&dp->dl_stid.sc_stateid);
> > -		path.mnt = currentfh->fh_export->ex_path.mnt;
> > -		path.dentry = currentfh->fh_dentry;
> > -		if (vfs_getattr(&path, &stat,
> > -				(STATX_SIZE | STATX_CTIME | STATX_CHANGE_COOKIE),
> > -				AT_STATX_SYNC_AS_STAT)) {
> > +		if (!nfs4_delegation_stat(dp, currentfh, &stat)) {
> >  			nfs4_put_stid(&dp->dl_stid);
> >  			destroy_delegation(dp);
> >  			goto out_no_deleg;
> >  		}
> > +		open->op_delegate_type = NFS4_OPEN_DELEGATE_WRITE;
> >  		dp->dl_cb_fattr.ncf_cur_fsize = stat.size;
> >  		dp->dl_cb_fattr.ncf_initial_cinfo =
> >  			nfsd4_change_attribute(&stat, d_inode(currentfh->fh_dentry));
> > +		trace_nfsd_deleg_write(&dp->dl_stid.sc_stateid);
> >  	} else {
> >  		open->op_delegate_type = NFS4_OPEN_DELEGATE_READ;
> >  		trace_nfsd_deleg_read(&dp->dl_stid.sc_stateid);
> > 
> > -- 
> > 2.46.0
> > 
>
Jeff Layton Sept. 6, 2024, 2:08 p.m. UTC | #3
On Thu, 2024-09-05 at 08:41 -0400, Jeff Layton wrote:
> At this point in compound processing, currentfh refers to the parent of
> the file, not the file itself. Get the correct dentry from the delegation
> stateid instead.
> 
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
>  fs/nfsd/nfs4state.c | 31 +++++++++++++++++++++++--------
>  1 file changed, 23 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index df69dc6af467..db90677fc016 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -5914,6 +5914,26 @@ static void nfsd4_open_deleg_none_ext(struct nfsd4_open *open, int status)
>  	}
>  }
>  
> +static bool
> +nfs4_delegation_stat(struct nfs4_delegation *dp, struct svc_fh *currentfh,
> +		     struct kstat *stat)
> +{
> +	struct nfsd_file *nf = find_rw_file(dp->dl_stid.sc_file);
> +	struct path path;
> +
> +	if (!nf)
> +		return false;
> +
> +	path.mnt = currentfh->fh_export->ex_path.mnt;
> +	path.dentry = file_dentry(nf->nf_file);
> +
> +	if (vfs_getattr(&path, stat,
> +			(STATX_INO | STATX_SIZE | STATX_CTIME | STATX_CHANGE_COOKIE),

Minor oversight here.

I added STATX_INO when I was debugging, but we don't need it here. We
should probably drop that flag (though it's mostly harmless). Chuck,
would you be ok with fixing that up?

> +			AT_STATX_SYNC_AS_STAT))
> +		return false;
> +	return true;
> +}
> +
>  /*
>   * The Linux NFS server does not offer write delegations to NFSv4.0
>   * clients in order to avoid conflicts between write delegations and
> @@ -5949,7 +5969,6 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
>  	int cb_up;
>  	int status = 0;
>  	struct kstat stat;
> -	struct path path;
>  
>  	cb_up = nfsd4_cb_channel_good(oo->oo_owner.so_client);
>  	open->op_recall = false;
> @@ -5985,20 +6004,16 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
>  	memcpy(&open->op_delegate_stateid, &dp->dl_stid.sc_stateid, sizeof(dp->dl_stid.sc_stateid));
>  
>  	if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE) {
> -		open->op_delegate_type = NFS4_OPEN_DELEGATE_WRITE;
> -		trace_nfsd_deleg_write(&dp->dl_stid.sc_stateid);
> -		path.mnt = currentfh->fh_export->ex_path.mnt;
> -		path.dentry = currentfh->fh_dentry;
> -		if (vfs_getattr(&path, &stat,
> -				(STATX_SIZE | STATX_CTIME | STATX_CHANGE_COOKIE),
> -				AT_STATX_SYNC_AS_STAT)) {
> +		if (!nfs4_delegation_stat(dp, currentfh, &stat)) {
>  			nfs4_put_stid(&dp->dl_stid);
>  			destroy_delegation(dp);
>  			goto out_no_deleg;
>  		}
> +		open->op_delegate_type = NFS4_OPEN_DELEGATE_WRITE;
>  		dp->dl_cb_fattr.ncf_cur_fsize = stat.size;
>  		dp->dl_cb_fattr.ncf_initial_cinfo =
>  			nfsd4_change_attribute(&stat, d_inode(currentfh->fh_dentry));
> +		trace_nfsd_deleg_write(&dp->dl_stid.sc_stateid);
>  	} else {
>  		open->op_delegate_type = NFS4_OPEN_DELEGATE_READ;
>  		trace_nfsd_deleg_read(&dp->dl_stid.sc_stateid);
> 

Thanks!
Chuck Lever III Sept. 6, 2024, 2:36 p.m. UTC | #4
On Fri, Sep 06, 2024 at 10:08:29AM -0400, Jeff Layton wrote:
> On Thu, 2024-09-05 at 08:41 -0400, Jeff Layton wrote:
> > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> > index df69dc6af467..db90677fc016 100644
> > --- a/fs/nfsd/nfs4state.c
> > +++ b/fs/nfsd/nfs4state.c
> > @@ -5914,6 +5914,26 @@ static void nfsd4_open_deleg_none_ext(struct nfsd4_open *open, int status)
> >  	}
> >  }
> >  
> > +static bool
> > +nfs4_delegation_stat(struct nfs4_delegation *dp, struct svc_fh *currentfh,
> > +		     struct kstat *stat)
> > +{
> > +	struct nfsd_file *nf = find_rw_file(dp->dl_stid.sc_file);
> > +	struct path path;
> > +
> > +	if (!nf)
> > +		return false;
> > +
> > +	path.mnt = currentfh->fh_export->ex_path.mnt;
> > +	path.dentry = file_dentry(nf->nf_file);
> > +
> > +	if (vfs_getattr(&path, stat,
> > +			(STATX_INO | STATX_SIZE | STATX_CTIME | STATX_CHANGE_COOKIE),
> 
> Minor oversight here.
> 
> I added STATX_INO when I was debugging, but we don't need it here. We
> should probably drop that flag (though it's mostly harmless). Chuck,
> would you be ok with fixing that up?

Fixed and squashed into nfsd-next.
Chuck Lever III Sept. 8, 2024, 6 p.m. UTC | #5
On Thu, Sep 05, 2024 at 08:41:45AM -0400, Jeff Layton wrote:
> At this point in compound processing, currentfh refers to the parent of
> the file, not the file itself. Get the correct dentry from the delegation
> stateid instead.
> 
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
>  fs/nfsd/nfs4state.c | 31 +++++++++++++++++++++++--------
>  1 file changed, 23 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index df69dc6af467..db90677fc016 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -5914,6 +5914,26 @@ static void nfsd4_open_deleg_none_ext(struct nfsd4_open *open, int status)
>  	}
>  }
>  
> +static bool
> +nfs4_delegation_stat(struct nfs4_delegation *dp, struct svc_fh *currentfh,
> +		     struct kstat *stat)
> +{
> +	struct nfsd_file *nf = find_rw_file(dp->dl_stid.sc_file);

The xfstests workflow on NFSv4.2 exhausts the capacity of both the
main and scratch devices (backed by xfs) about half-way through
each test run.

Deleting all visible files on both devices frees only a little bit
of space. The test exports can be unshared but not unmounted
(EBUSY). Looks like unlinked but still open files, maybe.

Bisected to this here patch.

Should there be a matching nfsd_file_put() book-end for the new
find_rw_file() call site?


> +	struct path path;
> +
> +	if (!nf)
> +		return false;
> +
> +	path.mnt = currentfh->fh_export->ex_path.mnt;
> +	path.dentry = file_dentry(nf->nf_file);
> +
> +	if (vfs_getattr(&path, stat,
> +			(STATX_INO | STATX_SIZE | STATX_CTIME | STATX_CHANGE_COOKIE),
> +			AT_STATX_SYNC_AS_STAT))
> +		return false;
> +	return true;
> +}
> +
>  /*
>   * The Linux NFS server does not offer write delegations to NFSv4.0
>   * clients in order to avoid conflicts between write delegations and
> @@ -5949,7 +5969,6 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
>  	int cb_up;
>  	int status = 0;
>  	struct kstat stat;
> -	struct path path;
>  
>  	cb_up = nfsd4_cb_channel_good(oo->oo_owner.so_client);
>  	open->op_recall = false;
> @@ -5985,20 +6004,16 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
>  	memcpy(&open->op_delegate_stateid, &dp->dl_stid.sc_stateid, sizeof(dp->dl_stid.sc_stateid));
>  
>  	if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE) {
> -		open->op_delegate_type = NFS4_OPEN_DELEGATE_WRITE;
> -		trace_nfsd_deleg_write(&dp->dl_stid.sc_stateid);
> -		path.mnt = currentfh->fh_export->ex_path.mnt;
> -		path.dentry = currentfh->fh_dentry;
> -		if (vfs_getattr(&path, &stat,
> -				(STATX_SIZE | STATX_CTIME | STATX_CHANGE_COOKIE),
> -				AT_STATX_SYNC_AS_STAT)) {
> +		if (!nfs4_delegation_stat(dp, currentfh, &stat)) {
>  			nfs4_put_stid(&dp->dl_stid);
>  			destroy_delegation(dp);
>  			goto out_no_deleg;
>  		}
> +		open->op_delegate_type = NFS4_OPEN_DELEGATE_WRITE;
>  		dp->dl_cb_fattr.ncf_cur_fsize = stat.size;
>  		dp->dl_cb_fattr.ncf_initial_cinfo =
>  			nfsd4_change_attribute(&stat, d_inode(currentfh->fh_dentry));
> +		trace_nfsd_deleg_write(&dp->dl_stid.sc_stateid);
>  	} else {
>  		open->op_delegate_type = NFS4_OPEN_DELEGATE_READ;
>  		trace_nfsd_deleg_read(&dp->dl_stid.sc_stateid);
> 
> -- 
> 2.46.0
>
Jeff Layton Sept. 8, 2024, 8:40 p.m. UTC | #6
On Sun, 2024-09-08 at 14:00 -0400, Chuck Lever wrote:
> On Thu, Sep 05, 2024 at 08:41:45AM -0400, Jeff Layton wrote:
> > At this point in compound processing, currentfh refers to the parent of
> > the file, not the file itself. Get the correct dentry from the delegation
> > stateid instead.
> > 
> > Signed-off-by: Jeff Layton <jlayton@kernel.org>
> > ---
> >  fs/nfsd/nfs4state.c | 31 +++++++++++++++++++++++--------
> >  1 file changed, 23 insertions(+), 8 deletions(-)
> > 
> > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> > index df69dc6af467..db90677fc016 100644
> > --- a/fs/nfsd/nfs4state.c
> > +++ b/fs/nfsd/nfs4state.c
> > @@ -5914,6 +5914,26 @@ static void nfsd4_open_deleg_none_ext(struct nfsd4_open *open, int status)
> >  	}
> >  }
> >  
> > +static bool
> > +nfs4_delegation_stat(struct nfs4_delegation *dp, struct svc_fh *currentfh,
> > +		     struct kstat *stat)
> > +{
> > +	struct nfsd_file *nf = find_rw_file(dp->dl_stid.sc_file);
> 
> The xfstests workflow on NFSv4.2 exhausts the capacity of both the
> main and scratch devices (backed by xfs) about half-way through
> each test run.
> 
> Deleting all visible files on both devices frees only a little bit
> of space. The test exports can be unshared but not unmounted
> (EBUSY). Looks like unlinked but still open files, maybe.
> 
> Bisected to this here patch.
> 
> Should there be a matching nfsd_file_put() book-end for the new
> find_rw_file() call site?
> 

Yes. Braino on my end. I was thinking that find_rw_file didn't take a
reference, but it does and we do need to put it. Would you like me to
respin, or do you just want to add it in the appropriate spot?

> 
> > +	struct path path;
> > +
> > +	if (!nf)
> > +		return false;
> > +
> > +	path.mnt = currentfh->fh_export->ex_path.mnt;
> > +	path.dentry = file_dentry(nf->nf_file);
> > +
> > +	if (vfs_getattr(&path, stat,
> > +			(STATX_INO | STATX_SIZE | STATX_CTIME | STATX_CHANGE_COOKIE),
> > +			AT_STATX_SYNC_AS_STAT))
> > +		return false;
> > +	return true;
> > +}
> > +
> >  /*
> >   * The Linux NFS server does not offer write delegations to NFSv4.0
> >   * clients in order to avoid conflicts between write delegations and
> > @@ -5949,7 +5969,6 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
> >  	int cb_up;
> >  	int status = 0;
> >  	struct kstat stat;
> > -	struct path path;
> >  
> >  	cb_up = nfsd4_cb_channel_good(oo->oo_owner.so_client);
> >  	open->op_recall = false;
> > @@ -5985,20 +6004,16 @@ nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
> >  	memcpy(&open->op_delegate_stateid, &dp->dl_stid.sc_stateid, sizeof(dp->dl_stid.sc_stateid));
> >  
> >  	if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE) {
> > -		open->op_delegate_type = NFS4_OPEN_DELEGATE_WRITE;
> > -		trace_nfsd_deleg_write(&dp->dl_stid.sc_stateid);
> > -		path.mnt = currentfh->fh_export->ex_path.mnt;
> > -		path.dentry = currentfh->fh_dentry;
> > -		if (vfs_getattr(&path, &stat,
> > -				(STATX_SIZE | STATX_CTIME | STATX_CHANGE_COOKIE),
> > -				AT_STATX_SYNC_AS_STAT)) {
> > +		if (!nfs4_delegation_stat(dp, currentfh, &stat)) {
> >  			nfs4_put_stid(&dp->dl_stid);
> >  			destroy_delegation(dp);
> >  			goto out_no_deleg;
> >  		}
> > +		open->op_delegate_type = NFS4_OPEN_DELEGATE_WRITE;
> >  		dp->dl_cb_fattr.ncf_cur_fsize = stat.size;
> >  		dp->dl_cb_fattr.ncf_initial_cinfo =
> >  			nfsd4_change_attribute(&stat, d_inode(currentfh->fh_dentry));
> > +		trace_nfsd_deleg_write(&dp->dl_stid.sc_stateid);
> >  	} else {
> >  		open->op_delegate_type = NFS4_OPEN_DELEGATE_READ;
> >  		trace_nfsd_deleg_read(&dp->dl_stid.sc_stateid);
> > 
> > -- 
> > 2.46.0
> > 
>
diff mbox series

Patch

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index df69dc6af467..db90677fc016 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -5914,6 +5914,26 @@  static void nfsd4_open_deleg_none_ext(struct nfsd4_open *open, int status)
 	}
 }
 
+static bool
+nfs4_delegation_stat(struct nfs4_delegation *dp, struct svc_fh *currentfh,
+		     struct kstat *stat)
+{
+	struct nfsd_file *nf = find_rw_file(dp->dl_stid.sc_file);
+	struct path path;
+
+	if (!nf)
+		return false;
+
+	path.mnt = currentfh->fh_export->ex_path.mnt;
+	path.dentry = file_dentry(nf->nf_file);
+
+	if (vfs_getattr(&path, stat,
+			(STATX_INO | STATX_SIZE | STATX_CTIME | STATX_CHANGE_COOKIE),
+			AT_STATX_SYNC_AS_STAT))
+		return false;
+	return true;
+}
+
 /*
  * The Linux NFS server does not offer write delegations to NFSv4.0
  * clients in order to avoid conflicts between write delegations and
@@ -5949,7 +5969,6 @@  nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
 	int cb_up;
 	int status = 0;
 	struct kstat stat;
-	struct path path;
 
 	cb_up = nfsd4_cb_channel_good(oo->oo_owner.so_client);
 	open->op_recall = false;
@@ -5985,20 +6004,16 @@  nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *stp,
 	memcpy(&open->op_delegate_stateid, &dp->dl_stid.sc_stateid, sizeof(dp->dl_stid.sc_stateid));
 
 	if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE) {
-		open->op_delegate_type = NFS4_OPEN_DELEGATE_WRITE;
-		trace_nfsd_deleg_write(&dp->dl_stid.sc_stateid);
-		path.mnt = currentfh->fh_export->ex_path.mnt;
-		path.dentry = currentfh->fh_dentry;
-		if (vfs_getattr(&path, &stat,
-				(STATX_SIZE | STATX_CTIME | STATX_CHANGE_COOKIE),
-				AT_STATX_SYNC_AS_STAT)) {
+		if (!nfs4_delegation_stat(dp, currentfh, &stat)) {
 			nfs4_put_stid(&dp->dl_stid);
 			destroy_delegation(dp);
 			goto out_no_deleg;
 		}
+		open->op_delegate_type = NFS4_OPEN_DELEGATE_WRITE;
 		dp->dl_cb_fattr.ncf_cur_fsize = stat.size;
 		dp->dl_cb_fattr.ncf_initial_cinfo =
 			nfsd4_change_attribute(&stat, d_inode(currentfh->fh_dentry));
+		trace_nfsd_deleg_write(&dp->dl_stid.sc_stateid);
 	} else {
 		open->op_delegate_type = NFS4_OPEN_DELEGATE_READ;
 		trace_nfsd_deleg_read(&dp->dl_stid.sc_stateid);