> Related to this, nothing sets STATX_ATTR_DAX into statx->attributes_mask, > anywhere in the kernel. > > The flag is set into statx->attributes in vfs_getattr_nosec(), but that > does not know whether the particular filesystem under query supports dax > or not. > > This is related to my other email about exactly what attributes_mask > means, so should STATX_ATTR_DAX be set in statx->attributes_mask only > in the filesystems that support dax? > > (And should that be done only if CONFIG_DAX is turned on, etc?) I think the mask/flag combinations should mean: mask:off, flag:off -> value unknown mask:off, flag:on -> N/A mask:on, flag:off -> value is off mask:on, flag:on -> value is on So mask should be off iff STATX_ATTR_DAX will not be set even if DAX is enabled on a particular inode (such as on an old kernel not supporting STATX_ATTR_DAX). Thanks, Miklos