On Fri, Oct 05, 2012 at 08:56:44PM +0900, ????????? wrote: > +struct node_footer { > + __le32 nid; /* node id */ > + __le32 ino; /* inode nunmber */ > + __le32 cold:1; /* cold mark */ > + __le32 fsync:1; /* fsync mark */ > + __le32 dentry:1; /* dentry mark */ > + __le32 offset:29; /* offset in inode's node space */
A bitfield for a on-disk structure? This will have endianity issues, (but I don't know if you intend to support big-endian). It's not enough to use cpu_to_le* as in fill_node_footer(...) { rn->footer.offset = cpu_to_le32(ofs); } because the bitfield inside the structure will be already defined reversed. The cpu_to_le macro will only convert value of 'ofs' but will place it to different bits than it would on a little-endian arch. There are macros to define bitfields in an endian-neutral way (or do it by #ifdefs though it also involves duplicating the item names), or you can alternatively use two structs fr disk-only and memory-only access, the disk one stores __le32 with value combined of all and the in-memory gets set up properly and will look like your current version of the structure. (More about not using bitfields http://yarchive.net/comp/linux/bitfields.html) > + __le64 cp_ver; /* checkpoint version */ > + __le32 next_blkaddr; /* next node page block address */ > +} __packed; > + david -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/