Messages in this thread | | | From | OGAWA Hirofumi <> | Subject | Re: [PATCH v5] fs: FAT: Add support for DOS 1.x formatted volumes | Date | Mon, 14 Apr 2014 07:14:51 +0900 |
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Conrad Meyer <cse.cem@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. -- OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
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