Merge tag 'nfs-for-5.3-4' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client bugfix from Trond Myklebust:
 "Regression fix inode fileid checks in attribute revalidation code"

* tag 'nfs-for-5.3-4' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  NFS: Fix inode fileid checks in attribute revalidation code

fs/nfs/inode.c

@@ -1403,11 +1403,12 @@ static int nfs_check_inode_attributes(struct inode *inode, struct nfs_fattr *fat
 	if (NFS_PROTO(inode)->have_delegation(inode, FMODE_READ))
 		return 0;
 
-	/* No fileid? Just exit */
-	if (!(fattr->valid & NFS_ATTR_FATTR_FILEID))
-		return 0;
+	if (!(fattr->valid & NFS_ATTR_FATTR_FILEID)) {
+		/* Only a mounted-on-fileid? Just exit */
+		if (fattr->valid & NFS_ATTR_FATTR_MOUNTED_ON_FILEID)
+			return 0;
 	/* Has the inode gone and changed behind our back? */
-	if (nfsi->fileid != fattr->fileid) {
+	} else if (nfsi->fileid != fattr->fileid) {
 		/* Is this perhaps the mounted-on fileid? */
 		if ((fattr->valid & NFS_ATTR_FATTR_MOUNTED_ON_FILEID) &&
 		    nfsi->fileid == fattr->mounted_on_fileid)
@@ -1807,11 +1808,12 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
 			nfs_display_fhandle_hash(NFS_FH(inode)),
 			atomic_read(&inode->i_count), fattr->valid);
 
-	/* No fileid? Just exit */
-	if (!(fattr->valid & NFS_ATTR_FATTR_FILEID))
-		return 0;
+	if (!(fattr->valid & NFS_ATTR_FATTR_FILEID)) {
+		/* Only a mounted-on-fileid? Just exit */
+		if (fattr->valid & NFS_ATTR_FATTR_MOUNTED_ON_FILEID)
+			return 0;
 	/* Has the inode gone and changed behind our back? */
-	if (nfsi->fileid != fattr->fileid) {
+	} else if (nfsi->fileid != fattr->fileid) {
 		/* Is this perhaps the mounted-on fileid? */
 		if ((fattr->valid & NFS_ATTR_FATTR_MOUNTED_ON_FILEID) &&
 		    nfsi->fileid == fattr->mounted_on_fileid)