142 	struct dentry *upper;  in ovl_dentry_revalidate_common()  local
150 	upper = ovl_i_dentry_upper(inode);  in ovl_dentry_revalidate_common()
151 	if (upper)  in ovl_dentry_revalidate_common()
152 		ret = ovl_revalidate_real(upper, flags, weak);  in ovl_dentry_revalidate_common()
265 /* Sync real dirty inodes in upper filesystem (if it exists) */
311  * Get the filesystem statistics.  As writes always target the upper layer
312  * filesystem pass the statfs to the upper filesystem (if it exists)
612 	/* Workdir/index are useless in non-upper mount */  in ovl_parse_opt()
615 			pr_info("option \"workdir=%s\" is useless in a non-upper mount, ignore\n",  in ovl_parse_opt()
621 			pr_info("option \"index=on\" is useless in a non-upper mount, ignore\n");  in ovl_parse_opt()
628 		pr_info("option \"volatile\" is meaningless in a non-upper mount, ignoring it.\n");  in ovl_parse_opt()
638 	 * difference, since config->redirect_dir is only used for upper.  in ovl_parse_opt()
667 …pr_info("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_exp…  in ovl_parse_opt()
770 		 * allowed as upper are limited to "normal" ones, where checking  in ovl_workdir_create()
1130 	/* Upper fs should not be r/o */  in ovl_get_upper()
1132 		pr_err("upper fs is r/o, try multi-lower layers mount\n");  in ovl_get_upper()
1309 	 * Upper should support d_type, else whiteouts are visible.  Given  in ovl_make_workdir()
1310 	 * workdir and upper are on same fs, we can do iterate_dir() on  in ovl_make_workdir()
1320 		pr_warn("upper fs needs to support d_type.\n");  in ovl_make_workdir()
1322 	/* Check if upper/work fs supports O_TMPFILE */  in ovl_make_workdir()
1328 		pr_warn("upper fs does not support tmpfile.\n");  in ovl_make_workdir()
1331 	/* Check if upper/work fs supports RENAME_WHITEOUT */  in ovl_make_workdir()
1338 		pr_warn("upper fs does not support RENAME_WHITEOUT.\n");  in ovl_make_workdir()
1341 	 * Check if upper/work fs supports trusted.overlay.* xattr  in ovl_make_workdir()
1348 		pr_warn("upper fs does not support xattr, falling back to index=off and metacopy=off.\n");  in ovl_make_workdir()
1355 	 * We allowed sub-optimal upper fs configuration and don't want to break  in ovl_make_workdir()
1356 	 * users over kernel upgrade, but we never allowed remote upper fs, so  in ovl_make_workdir()
1357 	 * we can enforce strict requirements for remote upper fs.  in ovl_make_workdir()
1361 		pr_err("upper fs missing required features.\n");  in ovl_make_workdir()
1378 	/* Check if upper/work fs supports file handles */  in ovl_make_workdir()
1382 		pr_warn("upper fs does not support file handles, falling back to index=off.\n");  in ovl_make_workdir()
1385 	/* Check if upper fs has 32bit inode numbers */  in ovl_make_workdir()
1453 	/* Verify lower root is upper root origin */  in ovl_get_indexdir()
1457 		pr_err("failed to verify upper root origin\n");  in ovl_get_indexdir()
1479 		 * Verify upper root is exclusively associated with index dir.  in ovl_get_indexdir()
1480 		 * Older kernels stored upper fh in "trusted.overlay.origin"  in ovl_get_indexdir()
1482 		 * upper dir file handle. In any case, verify or set xattr  in ovl_get_indexdir()
1483 		 * "trusted.overlay.upper" to indicate that index may have  in ovl_get_indexdir()
1496 			pr_err("failed to verify index dir 'upper' xattr\n");  in ovl_get_indexdir()
1523 	 * lower inode of non-dir upper.  in ovl_lower_uuid_ok()
1597 	/* idx/fsid 0 are reserved for upper fs even with lower only overlay */  in ovl_get_layers()
1601 	 * All lower layers that share the same fs as upper layer, use the same  in ovl_get_layers()
1602 	 * pseudo_dev as upper layer.  Allocate fs[0].pseudo_dev even for lower  in ovl_get_layers()
1604 	 * is_lower will be set if upper fs is shared with a lower layer.  in ovl_get_layers()
1608 		pr_err("failed to get anonymous bdev for upper fs\n");  in ovl_get_layers()
1686 		 * fsid, where fsid 0 is reserved for upper fs (even with  in ovl_get_layers()
1696 		pr_info("\"xino\" feature enabled using %d upper inode bits.\n",  in ovl_get_layers()
1768  * - upper/work dir of any overlayfs instance
1858 		/* Root inode uses upper st_ino/i_ino */  in ovl_get_root()
1934 	/* Layer 0 is reserved for upper even if there's no upper */  in ovl_fill_super()
1989 	/* If the upper fs is nonexistent, we mark overlayfs r/o too */  in ovl_fill_super()