On Sat, Sep 24, 2016 at 02:00:41PM +0800, Chao Yu wrote:
> On 2016/9/21 8:45, Jaegeuk Kim wrote:
> > @@ -259,40 +290,26 @@ static inline void fill_node_footer_blkaddr(struct
> > page *page, block_t blkaddr)
> > {
> > struct f2fs_checkpoint *ckpt = F2FS_CKPT(F2FS_P_SB(page));
> > struct f2fs_node *rn = F2FS_NODE(page);
> > + size_t crc_offset = le32_to_cpu(ckpt->checksum_offset);
> > + __u64 cp_ver = le64_to_cpu(ckpt->checkpoint_ver);
> > + __u64 crc;
> >
> > - rn->footer.cp_ver = ckpt->checkpoint_ver;
> > + crc = le32_to_cpu(*((__le32 *)((unsigned char *)ckpt + crc_offset)));
> > + cp_ver |= (crc << 32);
>
> How about using '^=' here?
The crc is already random enough, but has 32bits only.
The cp_ver is not easy to use over 32bits, so we don't need to keep the other
32bits untouched in most of life.
Thanks,
>
> > + rn->footer.cp_ver = cpu_to_le64(cp_ver);
> > rn->footer.next_blkaddr = cpu_to_le32(blkaddr);
> > }
> >
> > -static inline nid_t ino_of_node(struct page *node_page)
> > -{
> > - struct f2fs_node *rn = F2FS_NODE(node_page);
> > - return le32_to_cpu(rn->footer.ino);
> > -}
> > -
> > -static inline nid_t nid_of_node(struct page *node_page)
> > -{
> > - struct f2fs_node *rn = F2FS_NODE(node_page);
> > - return le32_to_cpu(rn->footer.nid);
> > -}
> > -
> > -static inline unsigned int ofs_of_node(struct page *node_page)
> > -{
> > - struct f2fs_node *rn = F2FS_NODE(node_page);
> > - unsigned flag = le32_to_cpu(rn->footer.flag);
> > - return flag >> OFFSET_BIT_SHIFT;
> > -}
> > -
> > -static inline unsigned long long cpver_of_node(struct page *node_page)
> > +static inline bool is_recoverable_dnode(struct page *page)
> > {
> > - struct f2fs_node *rn = F2FS_NODE(node_page);
> > - return le64_to_cpu(rn->footer.cp_ver);
> > -}
> > + struct f2fs_checkpoint *ckpt = F2FS_CKPT(F2FS_P_SB(page));
> > + size_t crc_offset = le32_to_cpu(ckpt->checksum_offset);
> > + __u64 cp_ver = cur_cp_version(ckpt);
> > + __u64 crc;
> >
> > -static inline block_t next_blkaddr_of_node(struct page *node_page)
> > -{
> > - struct f2fs_node *rn = F2FS_NODE(node_page);
> > - return le32_to_cpu(rn->footer.next_blkaddr);
> > + crc = le32_to_cpu(*((__le32 *)((unsigned char *)ckpt + crc_offset)));
> > + cp_ver |= (crc << 32);
> > + return cpu_to_le64(cp_ver) == cpver_of_node(page);
> > }
>
> cpu_to_le64(cp_ver) == cpver_of_node(page) ^ (crc << 32)
>
> Thanks,
