staging: exfat: Remove FAT/VFAT mount support, part 1

Remove the top-level mount functionality, to make this driver handle
only exfat file systems.
Signed-off-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Link: https://lore.kernel.org/r/20191112211238.156490-2-Valdis.Kletnieks@vt.eduSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/exfat/Kconfig

@@ -6,15 +6,6 @@ config EXFAT_FS
 	help
 	  This adds support for the exFAT file system.
 
-config EXFAT_DONT_MOUNT_VFAT
-	bool "Prohibit mounting of fat/vfat filesystems by exFAT"
-	depends on EXFAT_FS
-	default y
-	help
-	  By default, the exFAT driver will only mount exFAT filesystems, and refuse
-	  to mount fat/vfat filesystems.  Set this to 'n' to allow the exFAT driver
-	  to mount these filesystems.
-
 config EXFAT_DISCARD
 	bool "enable discard support"
 	depends on EXFAT_FS

drivers/staging/exfat/exfat.h

@@ -915,8 +915,6 @@ s32 resolve_path(struct inode *inode, char *path, struct chain_t *p_dir,
 s32 resolve_name(u8 *name, u8 **arg);
 
 /* file operation functions */
-s32 fat16_mount(struct super_block *sb, struct pbr_sector_t *p_pbr);
-s32 fat32_mount(struct super_block *sb, struct pbr_sector_t *p_pbr);
 s32 exfat_mount(struct super_block *sb, struct pbr_sector_t *p_pbr);
 s32 create_dir(struct inode *inode, struct chain_t *p_dir,
 	       struct uni_name_t *p_uniname, struct file_id_t *fid);

drivers/staging/exfat/exfat_core.c

@@ -1284,57 +1284,6 @@ s32 exfat_init_dir_entry(struct super_block *sb, struct chain_t *p_dir,
 	return 0;
 }
 
-static s32 fat_init_ext_entry(struct super_block *sb, struct chain_t *p_dir,
-			      s32 entry, s32 num_entries,
-			      struct uni_name_t *p_uniname,
-			      struct dos_name_t *p_dosname)
-{
-	int i;
-	sector_t sector;
-	u8 chksum;
-	u16 *uniname = p_uniname->name;
-	struct dos_dentry_t *dos_ep;
-	struct ext_dentry_t *ext_ep;
-
-	dos_ep = (struct dos_dentry_t *)get_entry_in_dir(sb, p_dir, entry,
-							 &sector);
-	if (!dos_ep)
-		return -EIO;
-
-	dos_ep->lcase = p_dosname->name_case;
-	memcpy(dos_ep->name, p_dosname->name, DOS_NAME_LENGTH);
-	buf_modify(sb, sector);
-
-	if ((--num_entries) > 0) {
-		chksum = calc_checksum_1byte((void *)dos_ep->name,
-					     DOS_NAME_LENGTH, 0);
-
-		for (i = 1; i < num_entries; i++) {
-			ext_ep = (struct ext_dentry_t *)get_entry_in_dir(sb,
-									 p_dir,
-									 entry - i,
-									 &sector);
-			if (!ext_ep)
-				return -EIO;
-
-			init_ext_entry(ext_ep, i, chksum, uniname);
-			buf_modify(sb, sector);
-			uniname += 13;
-		}
-
-		ext_ep = (struct ext_dentry_t *)get_entry_in_dir(sb, p_dir,
-								 entry - i,
-								 &sector);
-		if (!ext_ep)
-			return -EIO;
-
-		init_ext_entry(ext_ep, i + 0x40, chksum, uniname);
-		buf_modify(sb, sector);
-	}
-
-	return 0;
-}
-
 static s32 exfat_init_ext_entry(struct super_block *sb, struct chain_t *p_dir,
 				s32 entry, s32 num_entries,
 				struct uni_name_t *p_uniname,
@@ -2981,148 +2930,6 @@ s32 resolve_path(struct inode *inode, char *path, struct chain_t *p_dir,
 /*
  *  File Operation Functions
  */
-static struct fs_func fat_fs_func = {
-	.alloc_cluster = fat_alloc_cluster,
-	.free_cluster = fat_free_cluster,
-	.count_used_clusters = fat_count_used_clusters,
-
-	.init_dir_entry = fat_init_dir_entry,
-	.init_ext_entry = fat_init_ext_entry,
-	.find_dir_entry = fat_find_dir_entry,
-	.delete_dir_entry = fat_delete_dir_entry,
-	.get_uni_name_from_ext_entry = fat_get_uni_name_from_ext_entry,
-	.count_ext_entries = fat_count_ext_entries,
-	.calc_num_entries = fat_calc_num_entries,
-
-	.get_entry_type = fat_get_entry_type,
-	.set_entry_type = fat_set_entry_type,
-	.get_entry_attr = fat_get_entry_attr,
-	.set_entry_attr = fat_set_entry_attr,
-	.get_entry_flag = fat_get_entry_flag,
-	.set_entry_flag = fat_set_entry_flag,
-	.get_entry_clu0 = fat_get_entry_clu0,
-	.set_entry_clu0 = fat_set_entry_clu0,
-	.get_entry_size = fat_get_entry_size,
-	.set_entry_size = fat_set_entry_size,
-	.get_entry_time = fat_get_entry_time,
-	.set_entry_time = fat_set_entry_time,
-};
-
-s32 fat16_mount(struct super_block *sb, struct pbr_sector_t *p_pbr)
-{
-	s32 num_reserved, num_root_sectors;
-	struct bpb16_t *p_bpb = (struct bpb16_t *)p_pbr->bpb;
-	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
-	struct bd_info_t *p_bd = &(EXFAT_SB(sb)->bd_info);
-
-	if (p_bpb->num_fats == 0)
-		return -EFSCORRUPTED;
-
-	num_root_sectors = GET16(p_bpb->num_root_entries) << DENTRY_SIZE_BITS;
-	num_root_sectors = ((num_root_sectors - 1) >>
-			    p_bd->sector_size_bits) + 1;
-
-	p_fs->sectors_per_clu = p_bpb->sectors_per_clu;
-	p_fs->sectors_per_clu_bits = ilog2(p_bpb->sectors_per_clu);
-	p_fs->cluster_size_bits = p_fs->sectors_per_clu_bits +
-				  p_bd->sector_size_bits;
-	p_fs->cluster_size = 1 << p_fs->cluster_size_bits;
-
-	p_fs->num_FAT_sectors = GET16(p_bpb->num_fat_sectors);
-
-	p_fs->FAT1_start_sector = p_fs->PBR_sector + GET16(p_bpb->num_reserved);
-	if (p_bpb->num_fats == 1)
-		p_fs->FAT2_start_sector = p_fs->FAT1_start_sector;
-	else
-		p_fs->FAT2_start_sector = p_fs->FAT1_start_sector +
-					  p_fs->num_FAT_sectors;
-
-	p_fs->root_start_sector = p_fs->FAT2_start_sector +
-				  p_fs->num_FAT_sectors;
-	p_fs->data_start_sector = p_fs->root_start_sector + num_root_sectors;
-
-	p_fs->num_sectors = GET16(p_bpb->num_sectors);
-	if (p_fs->num_sectors == 0)
-		p_fs->num_sectors = GET32(p_bpb->num_huge_sectors);
-
-	num_reserved = p_fs->data_start_sector - p_fs->PBR_sector;
-	p_fs->num_clusters = ((p_fs->num_sectors - num_reserved) >>
-			      p_fs->sectors_per_clu_bits) + 2;
-	/* because the cluster index starts with 2 */
-
-	if (p_fs->num_clusters < FAT12_THRESHOLD)
-		p_fs->vol_type = FAT12;
-	else
-		p_fs->vol_type = FAT16;
-	p_fs->vol_id = GET32(p_bpb->vol_serial);
-
-	p_fs->root_dir = 0;
-	p_fs->dentries_in_root = GET16(p_bpb->num_root_entries);
-	p_fs->dentries_per_clu = 1 << (p_fs->cluster_size_bits -
-				       DENTRY_SIZE_BITS);
-
-	p_fs->vol_flag = VOL_CLEAN;
-	p_fs->clu_srch_ptr = 2;
-	p_fs->used_clusters = UINT_MAX;
-
-	p_fs->fs_func = &fat_fs_func;
-
-	return 0;
-}
-
-s32 fat32_mount(struct super_block *sb, struct pbr_sector_t *p_pbr)
-{
-	s32 num_reserved;
-	struct bpb32_t *p_bpb = (struct bpb32_t *)p_pbr->bpb;
-	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
-	struct bd_info_t *p_bd = &(EXFAT_SB(sb)->bd_info);
-
-	if (p_bpb->num_fats == 0)
-		return -EFSCORRUPTED;
-
-	p_fs->sectors_per_clu = p_bpb->sectors_per_clu;
-	p_fs->sectors_per_clu_bits = ilog2(p_bpb->sectors_per_clu);
-	p_fs->cluster_size_bits = p_fs->sectors_per_clu_bits +
-				  p_bd->sector_size_bits;
-	p_fs->cluster_size = 1 << p_fs->cluster_size_bits;
-
-	p_fs->num_FAT_sectors = GET32(p_bpb->num_fat32_sectors);
-
-	p_fs->FAT1_start_sector = p_fs->PBR_sector + GET16(p_bpb->num_reserved);
-	if (p_bpb->num_fats == 1)
-		p_fs->FAT2_start_sector = p_fs->FAT1_start_sector;
-	else
-		p_fs->FAT2_start_sector = p_fs->FAT1_start_sector +
-					  p_fs->num_FAT_sectors;
-
-	p_fs->root_start_sector = p_fs->FAT2_start_sector +
-				  p_fs->num_FAT_sectors;
-	p_fs->data_start_sector = p_fs->root_start_sector;
-
-	p_fs->num_sectors = GET32(p_bpb->num_huge_sectors);
-	num_reserved = p_fs->data_start_sector - p_fs->PBR_sector;
-
-	p_fs->num_clusters = ((p_fs->num_sectors - num_reserved) >>
-			      p_fs->sectors_per_clu_bits) + 2;
-	/* because the cluster index starts with 2 */
-
-	p_fs->vol_type = FAT32;
-	p_fs->vol_id = GET32(p_bpb->vol_serial);
-
-	p_fs->root_dir = GET32(p_bpb->root_cluster);
-	p_fs->dentries_in_root = 0;
-	p_fs->dentries_per_clu = 1 << (p_fs->cluster_size_bits -
-				       DENTRY_SIZE_BITS);
-
-	p_fs->vol_flag = VOL_CLEAN;
-	p_fs->clu_srch_ptr = 2;
-	p_fs->used_clusters = UINT_MAX;
-
-	p_fs->fs_func = &fat_fs_func;
-
-	return 0;
-}
-
 static struct fs_func exfat_fs_func = {
 	.alloc_cluster = exfat_alloc_cluster,
 	.free_cluster = exfat_free_cluster,

drivers/staging/exfat/exfat_super.c

@@ -396,16 +396,10 @@ static int ffsMountVol(struct super_block *sb)
 			break;
 
 	if (i < 53) {
-#ifdef CONFIG_EXFAT_DONT_MOUNT_VFAT
+		/* Not sure how we'd get here, but complain if it does */
 		ret = -EINVAL;
 		pr_info("EXFAT: Attempted to mount VFAT filesystem\n");
 		goto out;
-#else
-		if (GET16(p_pbr->bpb + 11)) /* num_fat_sectors */
-			ret = fat16_mount(sb, p_pbr);
-		else
-			ret = fat32_mount(sb, p_pbr);
-#endif
 	} else {
 		ret = exfat_mount(sb, p_pbr);
 	}