[PATCH v6 17/20] nfsd: add the filehandle to returned attributes in CB_NOTIFY

nfsd's usual fh_compose routine requires a svc_export and fills out a
svc_fh. In the context of a CB_NOTIFY there is no such export to
consult.

Add a new routine that composes a filehandle with only a parent
filehandle and nfs4_file. Use that to fill out the fhandle field in the
nfsd4_fattr_args.

Signed-off-by: Jeff Layton <[email protected]>
---
 fs/nfsd/nfs4xdr.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 7b19248b1503..15ccd54ffdb6 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -4197,6 +4197,39 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr,
 	goto out;
 }
 
+static bool
+setup_notify_fhandle(struct dentry *dentry, struct nfs4_file *fi,
+		     struct nfsd_file *nf, struct nfsd4_fattr_args *args)
+{
+	int fileid_type, fsid_len, maxsize, flags = 0;
+	struct knfsd_fh *fhp = &args->fhandle;
+	struct inode *inode = d_inode(dentry);
+	struct inode *parent = NULL;
+	struct fid *fid;
+
+	fsid_len = key_len(fi->fi_fhandle.fh_fsid_type);
+	fhp->fh_size = 4 + fsid_len;
+
+	/* Copy first 4 bytes + fsid */
+	memcpy(&fhp->fh_raw, &fi->fi_fhandle.fh_raw, fhp->fh_size);
+
+	fid = (struct fid *)(fh_fsid(fhp) + fsid_len/4);
+	maxsize = (NFS4_FHSIZE - fhp->fh_size)/4;
+
+	if (fi->fi_connectable && !S_ISDIR(inode->i_mode)) {
+		parent = d_inode(nf->nf_file->f_path.dentry);
+		flags = EXPORT_FH_CONNECTABLE;
+	}
+
+	fileid_type = exportfs_encode_inode_fh(inode, fid, &maxsize, parent, flags);
+	if (fileid_type < 0 || fileid_type == FILEID_INVALID)
+		return false;
+
+	fhp->fh_fileid_type = fileid_type;
+	fhp->fh_size += maxsize * 4;
+	return true;
+}
+
 #define CB_NOTIFY_STATX_REQUEST_MASK (STATX_BASIC_STATS   | \
 				      STATX_BTIME	  | \
 				      STATX_CHANGE_COOKIE)
@@ -4206,6 +4239,7 @@ nfsd4_setup_notify_entry4(struct notify_entry4 *ne, struct xdr_stream *xdr,
 			  struct dentry *dentry, struct nfs4_delegation *dp,
 			  struct nfsd_file *nf, char *name, u32 namelen)
 {
+	struct nfs4_file *fi = dp->dl_stid.sc_file;
 	struct path path =  { .mnt = nf->nf_file->f_path.mnt,
 			      .dentry = dentry };
 	struct nfsd4_fattr_args args = { };
@@ -4244,6 +4278,9 @@ nfsd4_setup_notify_entry4(struct notify_entry4 *ne, struct xdr_stream *xdr,
 		      FATTR4_WORD1_TIME_METADATA | FATTR4_WORD1_TIME_MODIFY;
 	attrmask[2] = 0;
 
+	if (setup_notify_fhandle(dentry, fi, nf, &args))
+		attrmask[0] |= FATTR4_WORD0_FILEHANDLE;
+
 	if (args.stat.result_mask & STATX_BTIME)
 		attrmask[1] |= FATTR4_WORD1_TIME_CREATE;
 

-- 
2.54.0