Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753877AbaDMD5t (ORCPT ); Sat, 12 Apr 2014 23:57:49 -0400 Received: from mail.parknet.co.jp ([210.171.160.6]:38787 "EHLO mail.parknet.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751548AbaDMD5r (ORCPT ); Sat, 12 Apr 2014 23:57:47 -0400 From: OGAWA Hirofumi To: Conrad Meyer Cc: linux-kernel@vger.kernel.org, Conrad Meyer Subject: Re: [PATCH v4] fs: FAT: Add support for DOS 1.x formatted volumes References: <1396279369-17855-1-git-send-email-cse.cem@gmail.com> <1396315037-12725-1-git-send-email-cse.cem@gmail.com> Date: Sun, 13 Apr 2014 12:57:42 +0900 In-Reply-To: <1396315037-12725-1-git-send-email-cse.cem@gmail.com> (Conrad Meyer's message of "Mon, 31 Mar 2014 18:17:17 -0700") Message-ID: <87zjjpvq2x.fsf@devron.myhome.or.jp> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Conrad Meyer writes: Hi, Sorry for late reply. > + > + bd_sects = part_nr_sects_read(sb->s_bdev->bd_part); This would be better to use i_read_size(&sb->s_bdev->bd_inode->i_size) > + if (!fat_bpb_is_zero(b)) { > + fat_msg(sb, KERN_ERR, "%s; DOS 2.x BPB is non-zero", > + notdos1x); > + brelse(bh); > + goto out_invalid; > + } Please don't message if silent. While auto detection, user don't want to see message from kernel. > + if (sbi->options.dos1xfloppy) { > + /* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */ > + if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) { > + fat_msg(sb, KERN_ERR, "%s; no bootstrapping code", > + notdos1x); > + brelse(bh); > + goto out_invalid; > + } [...] Looks like I was not explain my suggestion correctly. I was intended to allow dos1xfloppy by option, not allow dos1xfloppy only. I.e. err = read-from-bpb(); if (err == -ENOTFATFS) if (dos1xfloppy) err = read-from-static-bpb(); if (err) goto error; > + if (sbi->options.dos1xfloppy) > + total_sectors = fdefaults->nr_sectors; > + else > + total_sectors = get_unaligned_le16(&b->sectors); > if (total_sectors == 0) > total_sectors = le32_to_cpu(b->total_sect); Can we make 2 helpers to read from BPB and static BPB? If possible, we would not be bothered by if (dos1xfloppy), like above crappy pseudo. Thanks. -- OGAWA Hirofumi > + > + for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) { > + if (floppy_defaults[i].nr_sectors == bd_sects) { > + fdefaults = &floppy_defaults[i]; > + break; > + } > + } > + > + if (fdefaults == NULL) { > + fat_msg(sb, KERN_WARNING, > + "This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)", > + (u64)bd_sects); > + brelse(bh); > + goto out_invalid; > + } > + > + fat_msg(sb, KERN_INFO, > + "This looks like a DOS 1.x volume; assuming default BPB values"); > + } else { > + if (!b->reserved) { > + if (!silent) > + fat_msg(sb, KERN_ERR, > + "bogus number of reserved sectors"); > + brelse(bh); > + goto out_invalid; > + } > + if (!b->fats) { > + if (!silent) > + fat_msg(sb, KERN_ERR, > + "bogus number of FAT structure"); > + brelse(bh); > + goto out_invalid; > + } > } > > /* > @@ -1397,6 +1510,8 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat, > */ > > media = b->media; > + if (sbi->options.dos1xfloppy) > + media = fdefaults->media; > if (!fat_valid_media(media)) { > if (!silent) > fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)", > @@ -1404,7 +1519,10 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat, > brelse(bh); > goto out_invalid; > } > - logical_sector_size = get_unaligned_le16(&b->sector_size); > + if (sbi->options.dos1xfloppy) > + logical_sector_size = SECTOR_SIZE; > + else > + logical_sector_size = get_unaligned_le16(&b->sector_size); > if (!is_power_of_2(logical_sector_size) > || (logical_sector_size < 512) > || (logical_sector_size > 4096)) { > @@ -1414,7 +1532,10 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat, > brelse(bh); > goto out_invalid; > } > - sbi->sec_per_clus = b->sec_per_clus; > + if (sbi->options.dos1xfloppy) > + sbi->sec_per_clus = fdefaults->sec_per_clus; > + else > + sbi->sec_per_clus = b->sec_per_clus; > if (!is_power_of_2(sbi->sec_per_clus)) { > if (!silent) > fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u", > @@ -1450,10 +1571,18 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat, > mutex_init(&sbi->s_lock); > sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus; > sbi->cluster_bits = ffs(sbi->cluster_size) - 1; > - sbi->fats = b->fats; > + if (sbi->options.dos1xfloppy) > + sbi->fats = 2; > + else > + sbi->fats = b->fats; > sbi->fat_bits = 0; /* Don't know yet */ > - sbi->fat_start = le16_to_cpu(b->reserved); > - sbi->fat_length = le16_to_cpu(b->fat_length); > + if (sbi->options.dos1xfloppy) { > + sbi->fat_start = 1; > + sbi->fat_length = fdefaults->fat_length; > + } else { > + sbi->fat_start = le16_to_cpu(b->reserved); > + sbi->fat_length = le16_to_cpu(b->fat_length); > + } > sbi->root_cluster = 0; > sbi->free_clusters = -1; /* Don't know yet */ > sbi->free_clus_valid = 0; > @@ -1515,7 +1644,10 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat, > 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 = get_unaligned_le16(&b->dir_entries); > + if (sbi->options.dos1xfloppy) > + sbi->dir_entries = fdefaults->dir_entries; > + else > + sbi->dir_entries = get_unaligned_le16(&b->dir_entries); > if (sbi->dir_entries & (sbi->dir_per_block - 1)) { > if (!silent) > fat_msg(sb, KERN_ERR, "bogus directory-entries per block" > @@ -1527,7 +1659,10 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat, > rootdir_sectors = sbi->dir_entries > * sizeof(struct msdos_dir_entry) / sb->s_blocksize; > sbi->data_start = sbi->dir_start + rootdir_sectors; > - total_sectors = get_unaligned_le16(&b->sectors); > + if (sbi->options.dos1xfloppy) > + total_sectors = fdefaults->nr_sectors; > + else > + total_sectors = get_unaligned_le16(&b->sectors); > if (total_sectors == 0) > total_sectors = le32_to_cpu(b->total_sect); -- OGAWA Hirofumi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/