NFS: Fix up statx() results

If statx has valid attributes available that weren't asked for, then
return them and set the result mask appropriately.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/inode.c

@@ -806,6 +806,28 @@ static bool nfs_need_revalidate_inode(struct inode *inode)
 	return false;
 }
 
+static u32 nfs_get_valid_attrmask(struct inode *inode)
+{
+	unsigned long cache_validity = READ_ONCE(NFS_I(inode)->cache_validity);
+	u32 reply_mask = STATX_INO | STATX_TYPE;
+
+	if (!(cache_validity & NFS_INO_INVALID_ATIME))
+		reply_mask |= STATX_ATIME;
+	if (!(cache_validity & NFS_INO_REVAL_PAGECACHE)) {
+		if (!(cache_validity & NFS_INO_INVALID_CTIME))
+			reply_mask |= STATX_CTIME;
+		if (!(cache_validity & NFS_INO_INVALID_MTIME))
+			reply_mask |= STATX_MTIME;
+		if (!(cache_validity & NFS_INO_INVALID_SIZE))
+			reply_mask |= STATX_SIZE;
+	}
+	if (!(cache_validity & NFS_INO_INVALID_OTHER))
+		reply_mask |= STATX_UID | STATX_GID | STATX_MODE | STATX_NLINK;
+	if (!(cache_validity & NFS_INO_INVALID_BLOCKS))
+		reply_mask |= STATX_BLOCKS;
+	return reply_mask;
+}
+
 int nfs_getattr(struct user_namespace *mnt_userns, const struct path *path,
 		struct kstat *stat, u32 request_mask, unsigned int query_flags)
 {
@@ -824,7 +846,7 @@ int nfs_getattr(struct user_namespace *mnt_userns, const struct path *path,
 
 	if ((query_flags & AT_STATX_DONT_SYNC) && !force_sync) {
 		nfs_readdirplus_parent_cache_hit(path->dentry);
-		goto out_no_update;
+		goto out_no_revalidate;
 	}
 
 	/* Flush out writes to the server in order to update c/mtime.  */
@@ -870,6 +892,7 @@ int nfs_getattr(struct user_namespace *mnt_userns, const struct path *path,
 		do_update |= cache_validity & NFS_INO_INVALID_OTHER;
 	if (request_mask & STATX_BLOCKS)
 		do_update |= cache_validity & NFS_INO_INVALID_BLOCKS;
+
 	if (do_update) {
 		/* Update the attribute cache */
 		if (!(server->flags & NFS_MOUNT_NOAC))
@@ -883,8 +906,8 @@ int nfs_getattr(struct user_namespace *mnt_userns, const struct path *path,
 		nfs_readdirplus_parent_cache_hit(path->dentry);
 out_no_revalidate:
 	/* Only return attributes that were revalidated. */
-	stat->result_mask &= request_mask;
-out_no_update:
+	stat->result_mask = nfs_get_valid_attrmask(inode) | request_mask;
+
 	generic_fillattr(&init_user_ns, inode, stat);
 	stat->ino = nfs_compat_user_ino64(NFS_FILEID(inode));
 	if (S_ISDIR(inode->i_mode))