nfsd: have nfsd4_deleg_getattr_conflict pass back write deleg pointer

Currently we pass back the size and whether it has been modified, but
those just mirror values tracked inside the delegation. In a later
patch, we'll need to get at the timestamps in the delegation too, so
just pass back a reference to the write delegation, and use that to
properly override values in the iattr.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfs4state.c

@@ -8863,8 +8863,7 @@ nfsd4_get_writestateid(struct nfsd4_compound_state *cstate,
  * nfsd4_deleg_getattr_conflict - Recall if GETATTR causes conflict
  * @rqstp: RPC transaction context
  * @dentry: dentry of inode to be checked for a conflict
- * @modified: return true if file was modified
- * @size: new size of file if modified is true
+ * @pdp: returned WRITE delegation, if one was found
  *
  * This function is called when there is a conflict between a write
  * delegation and a change/size GETATTR from another client. The server
@@ -8874,11 +8873,12 @@ nfsd4_get_writestateid(struct nfsd4_compound_state *cstate,
  * 18.7.4.
  *
  * Returns 0 if there is no conflict; otherwise an nfs_stat
- * code is returned.
+ * code is returned. If @pdp is set to a non-NULL value, then the
+ * caller must put the reference.
  */
 __be32
 nfsd4_deleg_getattr_conflict(struct svc_rqst *rqstp, struct dentry *dentry,
-				bool *modified, u64 *size)
+			     struct nfs4_delegation **pdp)
 {
 	__be32 status;
 	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
@@ -8889,10 +8889,9 @@ nfsd4_deleg_getattr_conflict(struct svc_rqst *rqstp, struct dentry *dentry,
 	struct nfs4_cb_fattr *ncf;
 	struct inode *inode = d_inode(dentry);
 
-	*modified = false;
 	ctx = locks_inode_context(inode);
 	if (!ctx)
-		return 0;
+		return nfs_ok;
 
 #define NON_NFSD_LEASE ((void *)1)
 
@@ -8958,10 +8957,10 @@ nfsd4_deleg_getattr_conflict(struct svc_rqst *rqstp, struct dentry *dentry,
 			goto out_status;
 		}
 		ncf->ncf_cur_fsize = ncf->ncf_cb_fsize;
-		*size = ncf->ncf_cur_fsize;
-		*modified = true;
+		*pdp = dp;
+		return nfs_ok;
 	}
-	status = 0;
+	status = nfs_ok;
 out_status:
 	nfs4_put_stid(&dp->dl_stid);
 	return status;

fs/nfsd/nfs4xdr.c

@@ -3511,6 +3511,7 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr,
 		    int ignore_crossmnt)
 {
 	DECLARE_BITMAP(attr_bitmap, ARRAY_SIZE(nfsd4_enc_fattr4_encode_ops));
+	struct nfs4_delegation *dp = NULL;
 	struct nfsd4_fattr_args args;
 	struct svc_fh *tempfh = NULL;
 	int starting_len = xdr->buf->len;
@@ -3525,8 +3526,6 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr,
 		.dentry	= dentry,
 	};
 	unsigned long bit;
-	bool file_modified = false;
-	u64 size = 0;
 
 	WARN_ON_ONCE(bmval[1] & NFSD_WRITEONLY_ATTRS_WORD1);
 	WARN_ON_ONCE(!nfsd_attrs_supported(minorversion, bmval));
@@ -3555,19 +3554,24 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr,
 			goto out;
 	}
 	if (attrmask[0] & (FATTR4_WORD0_CHANGE | FATTR4_WORD0_SIZE)) {
-		status = nfsd4_deleg_getattr_conflict(rqstp, dentry,
-					&file_modified, &size);
+		status = nfsd4_deleg_getattr_conflict(rqstp, dentry, &dp);
 		if (status)
 			goto out;
 	}
 
 	err = vfs_getattr(&path, &args.stat,
 			  STATX_BASIC_STATS | STATX_BTIME | STATX_CHANGE_COOKIE,
 			  AT_STATX_SYNC_AS_STAT);
+	if (dp) {
+		struct nfs4_cb_fattr *ncf = &dp->dl_cb_fattr;
+
+		if (ncf->ncf_file_modified)
+			args.stat.size = ncf->ncf_cur_fsize;
+
+		nfs4_put_stid(&dp->dl_stid);
+	}
 	if (err)
 		goto out_nfserr;
-	if (file_modified)
-		args.stat.size = size;
 
 	if (!(args.stat.result_mask & STATX_BTIME))
 		/* underlying FS does not offer btime so we can't share it */

fs/nfsd/state.h

@@ -783,5 +783,5 @@ static inline bool try_to_expire_client(struct nfs4_client *clp)
 }
 
 extern __be32 nfsd4_deleg_getattr_conflict(struct svc_rqst *rqstp,
-		struct dentry *dentry, bool *file_modified, u64 *size);
+		struct dentry *dentry, struct nfs4_delegation **pdp);
 #endif   /* NFSD4_STATE_H */