diff mbox series

[4/9] nfs: Add export support for weak cache consistency attributes

Message ID 20211217215046.40316-5-trondmy@kernel.org (mailing list archive)
State New, archived
Headers show
Series Assorted patches for knfsd | expand

Commit Message

Trond Myklebust Dec. 17, 2021, 9:50 p.m. UTC 
From: Trond Myklebust <trond.myklebust@primarydata.com>

Allow knfsd to request weak cache consistency attributes on files that
have delegations and/or have up to date attribute caches.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Lance Shelton <lance.shelton@hammerspace.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 fs/nfs/export.c          | 24 ++++++++++++
 fs/nfsd/nfs3xdr.c        | 83 +++++++++++++++++++++++++++-------------
 fs/nfsd/nfs4xdr.c        |  6 +--
 fs/nfsd/vfs.c            | 14 +++++++
 fs/nfsd/vfs.h            |  5 ++-
 include/linux/exportfs.h |  3 ++
 6 files changed, 103 insertions(+), 32 deletions(-)

Comments

Chuck Lever Dec. 18, 2021, 9:16 p.m. UTC | #1 
> On Dec 17, 2021, at 4:50 PM, trondmy@kernel.org wrote:
> 
> From: Trond Myklebust <trond.myklebust@primarydata.com>
> 
> Allow knfsd to request weak cache consistency attributes on files that
> have delegations and/or have up to date attribute caches.
> 
> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
> Signed-off-by: Lance Shelton <lance.shelton@hammerspace.com>
> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

This one does not apply to v5.16-rc. Please rebase this series
and resend.

More below:


> ---
> fs/nfs/export.c          | 24 ++++++++++++
> fs/nfsd/nfs3xdr.c        | 83 +++++++++++++++++++++++++++-------------
> fs/nfsd/nfs4xdr.c        |  6 +--
> fs/nfsd/vfs.c            | 14 +++++++
> fs/nfsd/vfs.h            |  5 ++-
> include/linux/exportfs.h |  3 ++
> 6 files changed, 103 insertions(+), 32 deletions(-)
> 
> diff --git a/fs/nfs/export.c b/fs/nfs/export.c
> index 171c424cb6d5..967f8902c49b 100644
> --- a/fs/nfs/export.c
> +++ b/fs/nfs/export.c
> @@ -151,10 +151,34 @@ static u64 nfs_fetch_iversion(struct inode *inode)
> 	return inode_peek_iversion_raw(inode);
> }
> 
> +static int nfs_exp_getattr(struct path *path, struct kstat *stat, bool force)
> +{
> +	const unsigned long check_valid =
> +		NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_ATIME |
> +		NFS_INO_INVALID_CTIME | NFS_INO_INVALID_MTIME |
> +		NFS_INO_INVALID_SIZE | /* NFS_INO_INVALID_BLOCKS | */
> +		NFS_INO_INVALID_OTHER | NFS_INO_INVALID_NLINK;
> +	struct inode *inode = d_inode(path->dentry);
> +	int flags = force ? AT_STATX_SYNC_AS_STAT : AT_STATX_DONT_SYNC;
> +	int ret, ret2 = 0;
> +
> +	if (!force && nfs_check_cache_invalid(inode, check_valid))
> +		ret2 = -EAGAIN;
> +	ret = vfs_getattr(path, stat, STATX_BASIC_STATS & ~STATX_BLOCKS, flags);
> +	if (ret < 0)
> +		return ret;
> +	stat->blocks = nfs_calc_block_size(stat->size);
> +	if (S_ISDIR(inode->i_mode))
> +		stat->blksize = NFS_SERVER(inode)->dtsize;
> +	stat->result_mask |= STATX_BLOCKS;
> +	return ret2;
> +}
> +
> const struct export_operations nfs_export_ops = {
> 	.encode_fh = nfs_encode_fh,
> 	.fh_to_dentry = nfs_fh_to_dentry,
> 	.get_parent = nfs_get_parent,
> +	.getattr = nfs_exp_getattr,
> 	.fetch_iversion = nfs_fetch_iversion,
> 	.flags = EXPORT_OP_NOWCC|EXPORT_OP_NOSUBTREECHK|
> 		EXPORT_OP_CLOSE_BEFORE_UNLINK|EXPORT_OP_REMOTE_FS|
> diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
> index 0a5ebc52e6a9..81b6cf228517 100644
> --- a/fs/nfsd/nfs3xdr.c
> +++ b/fs/nfsd/nfs3xdr.c
> @@ -415,21 +415,14 @@ svcxdr_encode_pre_op_attr(struct xdr_stream *xdr, const struct svc_fh *fhp)
> 	return svcxdr_encode_wcc_attr(xdr, fhp);
> }
> 
> -/**
> - * svcxdr_encode_post_op_attr - Encode NFSv3 post-op attributes
> - * @rqstp: Context of a completed RPC transaction
> - * @xdr: XDR stream
> - * @fhp: File handle to encode
> - *
> - * Return values:
> - *   %false: Send buffer space was exhausted
> - *   %true: Success
> - */
> -bool
> -svcxdr_encode_post_op_attr(struct svc_rqst *rqstp, struct xdr_stream *xdr,
> -			   const struct svc_fh *fhp)
> +static bool
> +__svcxdr_encode_post_op_attr(struct svc_rqst *rqstp, struct xdr_stream *xdr,
> +			     const struct svc_fh *fhp, bool force)
> {
> 	struct dentry *dentry = fhp->fh_dentry;
> +	struct path path = {
> +		.dentry = dentry,
> +	};
> 	struct kstat stat;
> 
> 	/*
> @@ -437,9 +430,10 @@ svcxdr_encode_post_op_attr(struct svc_rqst *rqstp, struct xdr_stream *xdr,
> 	 * stale file handle. In this case, no attributes are
> 	 * returned.
> 	 */
> -	if (fhp->fh_no_wcc || !dentry || !d_really_is_positive(dentry))
> +	if (!dentry || !d_really_is_positive(dentry))
> 		goto no_post_op_attrs;
> -	if (fh_getattr(fhp, &stat) != nfs_ok)
> +	path.mnt = fhp->fh_export->ex_path.mnt;
> +	if (nfsd_getattr(&path, &stat, force) != nfs_ok)
> 		goto no_post_op_attrs;
> 
> 	if (xdr_stream_encode_item_present(xdr) < 0)
> @@ -454,6 +448,31 @@ svcxdr_encode_post_op_attr(struct svc_rqst *rqstp, struct xdr_stream *xdr,
> 	return xdr_stream_encode_item_absent(xdr) > 0;
> }
> 
> +/**
> + * svcxdr_encode_post_op_attr - Encode NFSv3 post-op attributes
> + * @rqstp: Context of a completed RPC transaction
> + * @xdr: XDR stream
> + * @fhp: File handle to encode
> + *
> + * Return values:
> + *   %false: Send buffer space was exhausted
> + *   %true: Success
> + */
> +bool
> +svcxdr_encode_post_op_attr(struct svc_rqst *rqstp, struct xdr_stream *xdr,
> +			   const struct svc_fh *fhp)
> +{
> +	return __svcxdr_encode_post_op_attr(rqstp, xdr, fhp, true);
> +}
> +
> +static bool
> +svcxdr_encode_post_op_attr_opportunistic(struct svc_rqst *rqstp,
> +					 struct xdr_stream *xdr,
> +					 const struct svc_fh *fhp)
> +{
> +	return __svcxdr_encode_post_op_attr(rqstp, xdr, fhp, !fhp->fh_no_wcc);
> +}

I don't quite understand the need for splitting encode_post_op_attr.
At the least, more commentary in the patch description would help.
For now, I will study this and get back to you.


> +
> /*
>  * Encode weak cache consistency data
>  */
> @@ -481,7 +500,7 @@ svcxdr_encode_wcc_data(struct svc_rqst *rqstp, struct xdr_stream *xdr,
> neither:
> 	if (xdr_stream_encode_item_absent(xdr) < 0)
> 		return false;
> -	if (!svcxdr_encode_post_op_attr(rqstp, xdr, fhp))
> +	if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr, fhp))
> 		return false;
> 
> 	return true;
> @@ -879,11 +898,13 @@ int nfs3svc_encode_lookupres(struct svc_rqst *rqstp, __be32 *p)
> 			return 0;
> 		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
> 			return 0;
> -		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->dirfh))
> +		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
> +							      &resp->dirfh))
> 			return 0;
> 		break;
> 	default:
> -		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->dirfh))
> +		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
> +							      &resp->dirfh))
> 			return 0;
> 	}
> 
> @@ -901,13 +922,15 @@ nfs3svc_encode_accessres(struct svc_rqst *rqstp, __be32 *p)
> 		return 0;
> 	switch (resp->status) {
> 	case nfs_ok:
> -		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
> +		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
> +							      &resp->fh))
> 			return 0;
> 		if (xdr_stream_encode_u32(xdr, resp->access) < 0)
> 			return 0;
> 		break;
> 	default:
> -		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
> +		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
> +							      &resp->fh))
> 			return 0;
> 	}
> 
> @@ -926,7 +949,8 @@ nfs3svc_encode_readlinkres(struct svc_rqst *rqstp, __be32 *p)
> 		return 0;
> 	switch (resp->status) {
> 	case nfs_ok:
> -		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
> +		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
> +							      &resp->fh))
> 			return 0;
> 		if (xdr_stream_encode_u32(xdr, resp->len) < 0)
> 			return 0;
> @@ -935,7 +959,8 @@ nfs3svc_encode_readlinkres(struct svc_rqst *rqstp, __be32 *p)
> 			return 0;
> 		break;
> 	default:
> -		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
> +		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
> +							      &resp->fh))
> 			return 0;
> 	}
> 
> @@ -954,7 +979,8 @@ nfs3svc_encode_readres(struct svc_rqst *rqstp, __be32 *p)
> 		return 0;
> 	switch (resp->status) {
> 	case nfs_ok:
> -		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
> +		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
> +							      &resp->fh))
> 			return 0;
> 		if (xdr_stream_encode_u32(xdr, resp->count) < 0)
> 			return 0;
> @@ -968,7 +994,8 @@ nfs3svc_encode_readres(struct svc_rqst *rqstp, __be32 *p)
> 			return 0;
> 		break;
> 	default:
> -		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
> +		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
> +							      &resp->fh))
> 			return 0;
> 	}
> 
> @@ -1065,7 +1092,8 @@ nfs3svc_encode_readdirres(struct svc_rqst *rqstp, __be32 *p)
> 		return 0;
> 	switch (resp->status) {
> 	case nfs_ok:
> -		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
> +		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
> +							      &resp->fh))
> 			return 0;
> 		if (!svcxdr_encode_cookieverf3(xdr, resp->verf))
> 			return 0;
> @@ -1077,7 +1105,8 @@ nfs3svc_encode_readdirres(struct svc_rqst *rqstp, __be32 *p)
> 			return 0;
> 		break;
> 	default:
> -		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
> +		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
> +							      &resp->fh))
> 			return 0;
> 	}
> 
> @@ -1221,7 +1250,7 @@ svcxdr_encode_entry3_plus(struct nfsd3_readdirres *resp, const char *name,
> 	if (compose_entry_fh(resp, fhp, name, namlen, ino) != nfs_ok)
> 		goto out_noattrs;
> 
> -	if (!svcxdr_encode_post_op_attr(resp->rqstp, xdr, fhp))
> +	if (!svcxdr_encode_post_op_attr_opportunistic(resp->rqstp, xdr, fhp))
> 		goto out;
> 	if (!svcxdr_encode_post_op_fh3(xdr, fhp))
> 		goto out;
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index 7abeccb975b2..e14af0383b70 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -2865,9 +2865,9 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
> 			goto out;
> 	}
> 
> -	err = vfs_getattr(&path, &stat, STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
> -	if (err)
> -		goto out_nfserr;
> +	status = nfsd_getattr(&path, &stat, true);
> +	if (status)
> +		goto out;
> 	if ((bmval0 & (FATTR4_WORD0_FILES_AVAIL | FATTR4_WORD0_FILES_FREE |
> 			FATTR4_WORD0_FILES_TOTAL | FATTR4_WORD0_MAXNAME)) ||
> 	    (bmval1 & (FATTR4_WORD1_SPACE_AVAIL | FATTR4_WORD1_SPACE_FREE |
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index a90cc08211a3..4d57befdac6e 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -2412,3 +2412,17 @@ nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
> 
> 	return err? nfserrno(err) : 0;
> }
> +
> +
> +__be32
> +nfsd_getattr(struct path *p, struct kstat *stat, bool force)
> +{
> +	const struct export_operations *ops = p->dentry->d_sb->s_export_op;
> +	int err;
> +
> +	if (ops->getattr)
> +		err = ops->getattr(p, stat, force);
> +	else
> +		err = vfs_getattr(p, stat, STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
> +	return err ? nfserrno(err) : 0;
> +}

Please add nfsd_getattr() in a separate patch ("Refactor:").
And please include a kerneldoc comment for it.


> diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
> index b21b76e6b9a8..6edae1b9a96e 100644
> --- a/fs/nfsd/vfs.h
> +++ b/fs/nfsd/vfs.h
> @@ -132,6 +132,8 @@ __be32		nfsd_statfs(struct svc_rqst *, struct svc_fh *,
> __be32		nfsd_permission(struct svc_rqst *, struct svc_export *,
> 				struct dentry *, int);
> 
> +__be32		nfsd_getattr(struct path *p, struct kstat *, bool);
> +
> static inline int fh_want_write(struct svc_fh *fh)
> {
> 	int ret;
> @@ -156,8 +158,7 @@ static inline __be32 fh_getattr(const struct svc_fh *fh, struct kstat *stat)
> {
> 	struct path p = {.mnt = fh->fh_export->ex_path.mnt,
> 			 .dentry = fh->fh_dentry};
> -	return nfserrno(vfs_getattr(&p, stat, STATX_BASIC_STATS,
> -				    AT_STATX_SYNC_AS_STAT));
> +	return nfsd_getattr(&p, stat, true);
> }
> 
> static inline int nfsd_create_is_exclusive(int createmode)
> diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
> index 3260fe714846..58f36022787e 100644
> --- a/include/linux/exportfs.h
> +++ b/include/linux/exportfs.h
> @@ -10,6 +10,8 @@ struct inode;
> struct iomap;
> struct super_block;
> struct vfsmount;
> +struct path;
> +struct kstat;
> 
> /* limit the handle size to NFSv4 handle size now */
> #define MAX_HANDLE_SZ 128
> @@ -224,6 +226,7 @@ struct export_operations {
> #define EXPORT_OP_SYNC_LOCKS		(0x20) /* Filesystem can't do
> 						  asychronous blocking locks */
> 	unsigned long	flags;
> +	int (*getattr)(struct path *, struct kstat *, bool);
> };
> 
> extern int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid,
> -- 
> 2.33.1
> 

--
Chuck Lever
diff mbox series

Patch

diff --git a/fs/nfs/export.c b/fs/nfs/export.c
index 171c424cb6d5..967f8902c49b 100644
--- a/fs/nfs/export.c
+++ b/fs/nfs/export.c
@@ -151,10 +151,34 @@  static u64 nfs_fetch_iversion(struct inode *inode)
 	return inode_peek_iversion_raw(inode);
 }
 
+static int nfs_exp_getattr(struct path *path, struct kstat *stat, bool force)
+{
+	const unsigned long check_valid =
+		NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_ATIME |
+		NFS_INO_INVALID_CTIME | NFS_INO_INVALID_MTIME |
+		NFS_INO_INVALID_SIZE | /* NFS_INO_INVALID_BLOCKS | */
+		NFS_INO_INVALID_OTHER | NFS_INO_INVALID_NLINK;
+	struct inode *inode = d_inode(path->dentry);
+	int flags = force ? AT_STATX_SYNC_AS_STAT : AT_STATX_DONT_SYNC;
+	int ret, ret2 = 0;
+
+	if (!force && nfs_check_cache_invalid(inode, check_valid))
+		ret2 = -EAGAIN;
+	ret = vfs_getattr(path, stat, STATX_BASIC_STATS & ~STATX_BLOCKS, flags);
+	if (ret < 0)
+		return ret;
+	stat->blocks = nfs_calc_block_size(stat->size);
+	if (S_ISDIR(inode->i_mode))
+		stat->blksize = NFS_SERVER(inode)->dtsize;
+	stat->result_mask |= STATX_BLOCKS;
+	return ret2;
+}
+
 const struct export_operations nfs_export_ops = {
 	.encode_fh = nfs_encode_fh,
 	.fh_to_dentry = nfs_fh_to_dentry,
 	.get_parent = nfs_get_parent,
+	.getattr = nfs_exp_getattr,
 	.fetch_iversion = nfs_fetch_iversion,
 	.flags = EXPORT_OP_NOWCC|EXPORT_OP_NOSUBTREECHK|
 		EXPORT_OP_CLOSE_BEFORE_UNLINK|EXPORT_OP_REMOTE_FS|
diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
index 0a5ebc52e6a9..81b6cf228517 100644
--- a/fs/nfsd/nfs3xdr.c
+++ b/fs/nfsd/nfs3xdr.c
@@ -415,21 +415,14 @@  svcxdr_encode_pre_op_attr(struct xdr_stream *xdr, const struct svc_fh *fhp)
 	return svcxdr_encode_wcc_attr(xdr, fhp);
 }
 
-/**
- * svcxdr_encode_post_op_attr - Encode NFSv3 post-op attributes
- * @rqstp: Context of a completed RPC transaction
- * @xdr: XDR stream
- * @fhp: File handle to encode
- *
- * Return values:
- *   %false: Send buffer space was exhausted
- *   %true: Success
- */
-bool
-svcxdr_encode_post_op_attr(struct svc_rqst *rqstp, struct xdr_stream *xdr,
-			   const struct svc_fh *fhp)
+static bool
+__svcxdr_encode_post_op_attr(struct svc_rqst *rqstp, struct xdr_stream *xdr,
+			     const struct svc_fh *fhp, bool force)
 {
 	struct dentry *dentry = fhp->fh_dentry;
+	struct path path = {
+		.dentry = dentry,
+	};
 	struct kstat stat;
 
 	/*
@@ -437,9 +430,10 @@  svcxdr_encode_post_op_attr(struct svc_rqst *rqstp, struct xdr_stream *xdr,
 	 * stale file handle. In this case, no attributes are
 	 * returned.
 	 */
-	if (fhp->fh_no_wcc || !dentry || !d_really_is_positive(dentry))
+	if (!dentry || !d_really_is_positive(dentry))
 		goto no_post_op_attrs;
-	if (fh_getattr(fhp, &stat) != nfs_ok)
+	path.mnt = fhp->fh_export->ex_path.mnt;
+	if (nfsd_getattr(&path, &stat, force) != nfs_ok)
 		goto no_post_op_attrs;
 
 	if (xdr_stream_encode_item_present(xdr) < 0)
@@ -454,6 +448,31 @@  svcxdr_encode_post_op_attr(struct svc_rqst *rqstp, struct xdr_stream *xdr,
 	return xdr_stream_encode_item_absent(xdr) > 0;
 }
 
+/**
+ * svcxdr_encode_post_op_attr - Encode NFSv3 post-op attributes
+ * @rqstp: Context of a completed RPC transaction
+ * @xdr: XDR stream
+ * @fhp: File handle to encode
+ *
+ * Return values:
+ *   %false: Send buffer space was exhausted
+ *   %true: Success
+ */
+bool
+svcxdr_encode_post_op_attr(struct svc_rqst *rqstp, struct xdr_stream *xdr,
+			   const struct svc_fh *fhp)
+{
+	return __svcxdr_encode_post_op_attr(rqstp, xdr, fhp, true);
+}
+
+static bool
+svcxdr_encode_post_op_attr_opportunistic(struct svc_rqst *rqstp,
+					 struct xdr_stream *xdr,
+					 const struct svc_fh *fhp)
+{
+	return __svcxdr_encode_post_op_attr(rqstp, xdr, fhp, !fhp->fh_no_wcc);
+}
+
 /*
  * Encode weak cache consistency data
  */
@@ -481,7 +500,7 @@  svcxdr_encode_wcc_data(struct svc_rqst *rqstp, struct xdr_stream *xdr,
 neither:
 	if (xdr_stream_encode_item_absent(xdr) < 0)
 		return false;
-	if (!svcxdr_encode_post_op_attr(rqstp, xdr, fhp))
+	if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr, fhp))
 		return false;
 
 	return true;
@@ -879,11 +898,13 @@  int nfs3svc_encode_lookupres(struct svc_rqst *rqstp, __be32 *p)
 			return 0;
 		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
 			return 0;
-		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->dirfh))
+		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
+							      &resp->dirfh))
 			return 0;
 		break;
 	default:
-		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->dirfh))
+		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
+							      &resp->dirfh))
 			return 0;
 	}
 
@@ -901,13 +922,15 @@  nfs3svc_encode_accessres(struct svc_rqst *rqstp, __be32 *p)
 		return 0;
 	switch (resp->status) {
 	case nfs_ok:
-		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
+		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
+							      &resp->fh))
 			return 0;
 		if (xdr_stream_encode_u32(xdr, resp->access) < 0)
 			return 0;
 		break;
 	default:
-		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
+		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
+							      &resp->fh))
 			return 0;
 	}
 
@@ -926,7 +949,8 @@  nfs3svc_encode_readlinkres(struct svc_rqst *rqstp, __be32 *p)
 		return 0;
 	switch (resp->status) {
 	case nfs_ok:
-		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
+		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
+							      &resp->fh))
 			return 0;
 		if (xdr_stream_encode_u32(xdr, resp->len) < 0)
 			return 0;
@@ -935,7 +959,8 @@  nfs3svc_encode_readlinkres(struct svc_rqst *rqstp, __be32 *p)
 			return 0;
 		break;
 	default:
-		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
+		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
+							      &resp->fh))
 			return 0;
 	}
 
@@ -954,7 +979,8 @@  nfs3svc_encode_readres(struct svc_rqst *rqstp, __be32 *p)
 		return 0;
 	switch (resp->status) {
 	case nfs_ok:
-		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
+		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
+							      &resp->fh))
 			return 0;
 		if (xdr_stream_encode_u32(xdr, resp->count) < 0)
 			return 0;
@@ -968,7 +994,8 @@  nfs3svc_encode_readres(struct svc_rqst *rqstp, __be32 *p)
 			return 0;
 		break;
 	default:
-		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
+		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
+							      &resp->fh))
 			return 0;
 	}
 
@@ -1065,7 +1092,8 @@  nfs3svc_encode_readdirres(struct svc_rqst *rqstp, __be32 *p)
 		return 0;
 	switch (resp->status) {
 	case nfs_ok:
-		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
+		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
+							      &resp->fh))
 			return 0;
 		if (!svcxdr_encode_cookieverf3(xdr, resp->verf))
 			return 0;
@@ -1077,7 +1105,8 @@  nfs3svc_encode_readdirres(struct svc_rqst *rqstp, __be32 *p)
 			return 0;
 		break;
 	default:
-		if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh))
+		if (!svcxdr_encode_post_op_attr_opportunistic(rqstp, xdr,
+							      &resp->fh))
 			return 0;
 	}
 
@@ -1221,7 +1250,7 @@  svcxdr_encode_entry3_plus(struct nfsd3_readdirres *resp, const char *name,
 	if (compose_entry_fh(resp, fhp, name, namlen, ino) != nfs_ok)
 		goto out_noattrs;
 
-	if (!svcxdr_encode_post_op_attr(resp->rqstp, xdr, fhp))
+	if (!svcxdr_encode_post_op_attr_opportunistic(resp->rqstp, xdr, fhp))
 		goto out;
 	if (!svcxdr_encode_post_op_fh3(xdr, fhp))
 		goto out;
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 7abeccb975b2..e14af0383b70 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2865,9 +2865,9 @@  nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 			goto out;
 	}
 
-	err = vfs_getattr(&path, &stat, STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
-	if (err)
-		goto out_nfserr;
+	status = nfsd_getattr(&path, &stat, true);
+	if (status)
+		goto out;
 	if ((bmval0 & (FATTR4_WORD0_FILES_AVAIL | FATTR4_WORD0_FILES_FREE |
 			FATTR4_WORD0_FILES_TOTAL | FATTR4_WORD0_MAXNAME)) ||
 	    (bmval1 & (FATTR4_WORD1_SPACE_AVAIL | FATTR4_WORD1_SPACE_FREE |
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index a90cc08211a3..4d57befdac6e 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -2412,3 +2412,17 @@  nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
 
 	return err? nfserrno(err) : 0;
 }
+
+
+__be32
+nfsd_getattr(struct path *p, struct kstat *stat, bool force)
+{
+	const struct export_operations *ops = p->dentry->d_sb->s_export_op;
+	int err;
+
+	if (ops->getattr)
+		err = ops->getattr(p, stat, force);
+	else
+		err = vfs_getattr(p, stat, STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
+	return err ? nfserrno(err) : 0;
+}
diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
index b21b76e6b9a8..6edae1b9a96e 100644
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -132,6 +132,8 @@  __be32		nfsd_statfs(struct svc_rqst *, struct svc_fh *,
 __be32		nfsd_permission(struct svc_rqst *, struct svc_export *,
 				struct dentry *, int);
 
+__be32		nfsd_getattr(struct path *p, struct kstat *, bool);
+
 static inline int fh_want_write(struct svc_fh *fh)
 {
 	int ret;
@@ -156,8 +158,7 @@  static inline __be32 fh_getattr(const struct svc_fh *fh, struct kstat *stat)
 {
 	struct path p = {.mnt = fh->fh_export->ex_path.mnt,
 			 .dentry = fh->fh_dentry};
-	return nfserrno(vfs_getattr(&p, stat, STATX_BASIC_STATS,
-				    AT_STATX_SYNC_AS_STAT));
+	return nfsd_getattr(&p, stat, true);
 }
 
 static inline int nfsd_create_is_exclusive(int createmode)
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index 3260fe714846..58f36022787e 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -10,6 +10,8 @@  struct inode;
 struct iomap;
 struct super_block;
 struct vfsmount;
+struct path;
+struct kstat;
 
 /* limit the handle size to NFSv4 handle size now */
 #define MAX_HANDLE_SZ 128
@@ -224,6 +226,7 @@  struct export_operations {
 #define EXPORT_OP_SYNC_LOCKS		(0x20) /* Filesystem can't do
 						  asychronous blocking locks */
 	unsigned long	flags;
+	int (*getattr)(struct path *, struct kstat *, bool);
 };
 
 extern int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid,