On Mon, 14 Apr 2014 07:14:51 +0900 OGAWA Hirofumi <hirof...@mail.parknet.co.jp> wrote:
> Conrad Meyer <cse....@gmail.com> writes: > > > + sbi->sec_per_clus = fdefaults->sec_per_clus; > > + sbi->cluster_size = sb->s_blocksize * > > sbi->sec_per_clus; > > + sbi->cluster_bits = ffs(sbi->cluster_size) - 1; > > + sbi->fats = 2; > > + sbi->fat_start = 1; > > + sbi->fat_length = fdefaults->fat_length; > > + > > + sbi->dir_per_block = sb->s_blocksize / > > sizeof(struct msdos_dir_entry); > > + sbi->dir_per_block_bits = > > ffs(sbi->dir_per_block) - 1; > > + sbi->dir_start = sbi->fat_start + sbi->fats * > > sbi->fat_length; > > + sbi->dir_entries = fdefaults->dir_entries; > > + > > + rootdir_sectors = sbi->dir_entries > > + * sizeof(struct msdos_dir_entry) / > > sb->s_blocksize; > > + sbi->data_start = sbi->dir_start + > > rootdir_sectors; > > + total_sectors = fdefaults->nr_sectors; > > + total_clusters = (total_sectors - > > sbi->data_start) / sbi->sec_per_clus; > > + sbi->fat_bits = (total_clusters > MAX_FAT12) ? > > 16 : 12; + > > + /* some OSes set FAT_STATE_DIRTY and clean it on > > unmount. */ > > + sbi->dirty = b->fat16.state & FAT_STATE_DIRTY; > > + > > + /* check that FAT table does not overflow */ > > + fat_clusters = calc_fat_clusters(sb); > > + total_clusters = min(total_clusters, > > fat_clusters - FAT_START_ENT); > > Ah, you meant this duplicated one. > > Let's use structure like fat_boot_sector (but more cpu > friendly) on stack or something, instead of modify bh > (BPB). Modifying bh in bdev is visible via /dev/foo, this > is why I want to avoid to modify. > > With this, we can share almost all codes on both of > read_bpb() and static_bpb(), and avoids to modify bdev > buffer? And those 2 helpers only has small chunk of code, > and provide the required parameters? > > Thanks. Hi, I think I understand the idea, sounds good to me. Working to clean up now. Thanks again, Conrad -- 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/
