20 /* Get write access to upper mnt - may fail if upper sb was remounted ro */
27 /* Get write access to upper sb - may block if upper sb is frozen */
493  * to return positive, while there's no actual upper alias for the inode.
494  * Copy up code needs to know about the existence of the upper alias, so it
632  * Use this over ovl_is_whiteout for upper and lower files, as it also
690 	 * Check if copy-up has happened as well as for upper alias (in  in ovl_already_copied_up()
697 	 *      upper dentry is up-to-date  in ovl_already_copied_up()
699 	 *      upper parent i_rwsem to prevent reordering copy-up  in ovl_already_copied_up()
711  * The copy up "transaction" keeps an elevated mnt write count on upper mnt,
712  * but leaves taking freeze protection on upper sb to lower level helpers.
792 	 * of new overlays where upper root dir is not yet marked as impure.  in ovl_init_uuid_xattr()
793 	 * An upper dir is marked as impure on copy up or lookup of its subdirs.  in ovl_init_uuid_xattr()
850 #define OVL_XATTR_UPPER_POSTFIX		"upper"
885 		pr_warn("cannot set %s xattr on upper\n", ovl_xattr(ofs, ox));  in ovl_check_setxattr()
902 	 * Do not fail when upper doesn't support xattrs.  in ovl_set_impure()
903 	 * Upper inodes won't have origin nor redirect xattr anyway.  in ovl_set_impure()
915 void ovl_check_protattr(struct inode *inode, struct dentry *upper)  in ovl_check_protattr()  argument
922 	res = ovl_getxattr_upper(ofs, upper, OVL_XATTR_PROTATTR, buf,  in ovl_check_protattr()
928 	 * Initialize inode flags from overlay.protattr xattr and upper inode  in ovl_check_protattr()
929 	 * flags.  If upper inode has those fileattr flags set (i.e. from old  in ovl_check_protattr()
944 				    upper, res);  in ovl_check_protattr()
950 int ovl_set_protattr(struct inode *inode, struct dentry *upper,  in ovl_set_protattr()  argument
970 	 * Do not allow to set protection flags when upper doesn't support  in ovl_set_protattr()
971 	 * xattrs, because we do not set those fileattr flags on upper inode.  in ovl_set_protattr()
975 		err = ovl_check_setxattr(ofs, upper, OVL_XATTR_PROTATTR,  in ovl_set_protattr()
978 		err = ovl_removexattr(ofs, upper, OVL_XATTR_PROTATTR);  in ovl_set_protattr()
987 	/* Mask out the fileattr flags that should not be set in upper inode */  in ovl_set_protattr()
1089 		 * overlay nlink to zero before all upper inodes are unlinked.  in ovl_cleanup_index()
1130  * Operations that change overlay inode and upper inode nlink need to be
1146 	 * first copy up, we have no upper index inode to store the xattr.  in ovl_nlink_start()
1149 	 * copy up to create the upper index. Creating the upper index will  in ovl_nlink_start()
1176 	 * upper operation succeeds, along with nlink change of upper inode.  in ovl_nlink_start()
1178 	 * value relative to the upper inode nlink in an upper inode xattr.  in ovl_nlink_start()
1504  * When overlay copies inode information from an upper or lower layer to the
1505  * relevant overlay inode it will apply the idmapping of the upper or lower
1507  * reflect the ownership of the idmapped upper or lower layer. For example, an
1508  * idmapped upper or lower layer mapping id 1001 to id 1000 will take care to
1509  * map any lower or upper inode owned by id 1001 to id 1000. These mapping