Re: [PATCH v2 01/13] exfat: add in-memory and on-disk structures and headers

[Nikolay Borisov]

On 19.11.19 Ð. 9:10 Ñ., Namjae Jeon wrote:
> This adds in-memory and on-disk structures and headers.
> 
> Signed-off-by: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>
> Signed-off-by: Sungjong Seo <sj1557.seo@xxxxxxxxxxx>
> ---
>  fs/exfat/exfat_fs.h  | 534 +++++++++++++++++++++++++++++++++++++++++++
>  fs/exfat/exfat_raw.h | 190 +++++++++++++++
>  2 files changed, 724 insertions(+)
>  create mode 100644 fs/exfat/exfat_fs.h
>  create mode 100644 fs/exfat/exfat_raw.h
> 
> diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h
> new file mode 100644
> index 000000000000..6e1c738e520a
> --- /dev/null
> +++ b/fs/exfat/exfat_fs.h
> @@ -0,0 +1,534 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
> + */
> +
> +#ifndef _EXFAT_H
> +#define _EXFAT_H
> +
> +#include <linux/fs.h>
> +#include <linux/ratelimit.h>
> +
> +#define EXFAT_SUPER_MAGIC       (0x2011BAB0UL)
> +#define EXFAT_ROOT_INO		1
> +
> +enum exfat_time_mode {
> +	TM_CREATE,
> +	TM_MODIFY,
> +	TM_ACCESS,
> +};
> +
> +/*
> + * exfat error flags
> + */
> +enum exfat_error_mode {
> +	EXFAT_ERRORS_CONT,	/* ignore error and continue */
> +	EXFAT_ERRORS_PANIC,	/* panic on error */
> +	EXFAT_ERRORS_RO,	/* remount r/o on error */
> +};
> +
> +/*
> + * exfat nls lossy flag
> + */
> +#define NLS_NAME_NO_LOSSY	(0x00) /* no lossy */
> +#define NLS_NAME_LOSSY		(0x01) /* just detected incorrect filename(s) */
> +#define NLS_NAME_OVERLEN	(0x02) /* the length is over than its limit */
> +
> +/*
> + * exfat common MACRO
> + */
> +#define CLUSTER_32(x)	((unsigned int)((x) & 0xFFFFFFFFU))
> +#define EOF_CLUSTER	CLUSTER_32(~0)
> +#define BAD_CLUSTER	(0xFFFFFFF7U)
> +#define FREE_CLUSTER	(0)
> +#define BASE_CLUSTER	(2)
> +
> +#define EXFAT_HASH_BITS		8
> +#define EXFAT_HASH_SIZE		(1UL << EXFAT_HASH_BITS)
> +
> +/*
> + * Type Definitions
> + */
> +#define ES_2_ENTRIES	2
> +#define ES_ALL_ENTRIES	0
> +
> +#define DIR_DELETED	0xFFFF0321
> +
> +/* type values */
> +#define TYPE_UNUSED		0x0000
> +#define TYPE_DELETED		0x0001
> +#define TYPE_INVALID		0x0002
> +#define TYPE_CRITICAL_PRI	0x0100
> +#define TYPE_BITMAP		0x0101
> +#define TYPE_UPCASE		0x0102
> +#define TYPE_VOLUME		0x0103
> +#define TYPE_DIR		0x0104
> +#define TYPE_FILE		0x011F
> +#define TYPE_CRITICAL_SEC	0x0200
> +#define TYPE_STREAM		0x0201
> +#define TYPE_EXTEND		0x0202
> +#define TYPE_ACL		0x0203
> +#define TYPE_BENIGN_PRI		0x0400
> +#define TYPE_GUID		0x0401
> +#define TYPE_PADDING		0x0402
> +#define TYPE_ACLTAB		0x0403
> +#define TYPE_BENIGN_SEC		0x0800
> +#define TYPE_ALL		0x0FFF
> +
> +#define MAX_CHARSET_SIZE	6 /* max size of multi-byte character */
> +#define MAX_NAME_LENGTH		255 /* max len of file name excluding NULL */
> +#define MAX_VFSNAME_BUF_SIZE	((MAX_NAME_LENGTH + 1) * MAX_CHARSET_SIZE)
> +
> +#define FAT_CACHE_SIZE		128
> +#define FAT_CACHE_HASH_SIZE	64
> +#define BUF_CACHE_SIZE		256
> +#define BUF_CACHE_HASH_SIZE	64
> +
> +#define EXFAT_HINT_NONE		-1
> +#define EXFAT_MIN_SUBDIR	2
> +
> +/*
> + * helpers for cluster size to byte conversion.
> + */
> +#define EXFAT_CLU_TO_B(b, sbi)		((b) << (sbi)->cluster_size_bits)
> +#define EXFAT_B_TO_CLU(b, sbi)		((b) >> (sbi)->cluster_size_bits)
> +#define EXFAT_B_TO_CLU_ROUND_UP(b, sbi)	\
> +	(((b - 1) >> (sbi)->cluster_size_bits) + 1)
> +#define EXFAT_CLU_OFFSET(off, sbi)	((off) & ((sbi)->cluster_size - 1))
> +
> +/*
> + * helpers for block size to byte conversion.
> + */
> +#define EXFAT_BLK_TO_B(b, sb)		((b) << (sb)->s_blocksize_bits)
> +#define EXFAT_B_TO_BLK(b, sb)		((b) >> (sb)->s_blocksize_bits)
> +#define EXFAT_B_TO_BLK_ROUND_UP(b, sb)	\
> +	(((b - 1) >> (sb)->s_blocksize_bits) + 1)
> +#define EXFAT_BLK_OFFSET(off, sb)	((off) & ((sb)->s_blocksize - 1))
> +
> +/*
> + * helpers for block size to dentry size conversion.
> + */
> +#define EXFAT_B_TO_DEN_IDX(b, sbi)	\
> +	((b) << ((sbi)->cluster_size_bits - DENTRY_SIZE_BITS))
> +#define EXFAT_B_TO_DEN(b)		((b) >> DENTRY_SIZE_BITS)
> +#define EXFAT_DEN_TO_B(b)		((b) << DENTRY_SIZE_BITS)
> +
> +struct exfat_timestamp {
> +	unsigned short sec;	/* 0 ~ 59 */
> +	unsigned short min;	/* 0 ~ 59 */
> +	unsigned short hour;	/* 0 ~ 23 */
> +	unsigned short day;	/* 1 ~ 31 */
> +	unsigned short mon;	/* 1 ~ 12 */
> +	unsigned short year;	/* 0 ~ 127 (since 1980) */
> +};
> +
> +struct exfat_date_time {
> +	unsigned short year;
> +	unsigned short month;
> +	unsigned short day;
> +	unsigned short hour;
> +	unsigned short minute;
> +	unsigned short second;
> +	unsigned short milli_second;
> +};
> +
> +struct exfat_dentry_namebuf {
> +	char *lfn;
> +	int lfnbuf_len; /* usally MAX_UNINAME_BUF_SIZE */
> +};
> +
> +/* unicode name structure */
> +struct exfat_uni_name {
> +	/* +3 for null and for converting */
> +	unsigned short name[MAX_NAME_LENGTH + 3];
> +	unsigned short name_hash;
> +	unsigned char name_len;
> +};
> +
> +/* directory structure */
> +struct exfat_chain {
> +	unsigned int dir;
> +	unsigned int size;
> +	unsigned char flags;
> +};
> +
> +/* first empty entry hint information */
> +struct exfat_hint_femp {
> +	/* entry index of a directory */
> +	int eidx;
> +	/* count of continuous empty entry */
> +	int count;
> +	/* the cluster that first empty slot exists in */
> +	struct exfat_chain cur;
> +};
> +
> +/* hint structure */
> +struct exfat_hint {
> +	unsigned int clu;
> +	union {
> +		unsigned int off; /* cluster offset */
> +		int eidx; /* entry index */
> +	};
> +};
> +
> +struct exfat_entry_set_cache {
> +	/* sector number that contains file_entry */
> +	sector_t sector;
> +	/* byte offset in the sector */
> +	unsigned int offset;
> +	/* flag in stream entry. 01 for cluster chain, 03 for contig. */
> +	int alloc_flag;
> +	unsigned int num_entries;
> +	struct exfat_dentry entries[];
> +};
> +
> +struct exfat_dir_entry {
> +	struct exfat_chain dir;
> +	int entry;
> +	unsigned int type;
> +	unsigned int start_clu;
> +	unsigned char flags;
> +	unsigned short attr;
> +	loff_t size;
> +	unsigned int num_subdirs;
> +	struct exfat_date_time create_timestamp;
> +	struct exfat_date_time modify_timestamp;
> +	struct exfat_date_time access_timestamp;
> +	struct exfat_dentry_namebuf namebuf;
> +};
> +
> +/*
> + * exfat mount in-memory data
> + */
> +struct exfat_mount_options {
> +	kuid_t fs_uid;
> +	kgid_t fs_gid;
> +	unsigned short fs_fmask;
> +	unsigned short fs_dmask;
> +	/* permission for setting the [am]time */
> +	unsigned short allow_utime;
> +	/* charset for filename input/display */
> +	char *iocharset;
> +	unsigned char utf8;
> +	unsigned char case_sensitive;
> +	unsigned char tz_utc;
> +	/* on error: continue, panic, remount-ro */
> +	enum exfat_error_mode errors;
> +	/* flag on if -o dicard specified and device support discard() */
> +	unsigned char discard;
> +};
> +
> +/*
> + * EXFAT file system superblock in-memory data
> + */
> +struct exfat_sb_info {
> +	unsigned int vol_type; /* volume FAT type */
> +	unsigned int vol_id; /* volume serial number */
> +	unsigned long long num_sectors; /* num of sectors in volume */
> +	unsigned int num_clusters; /* num of clusters in volume */
> +	unsigned int cluster_size; /* cluster size in bytes */
> +	unsigned int cluster_size_bits;
> +	unsigned int sect_per_clus; /* cluster size in sectors */
> +	unsigned int sect_per_clus_bits;
> +	unsigned long long FAT1_start_sector; /* FAT1 start sector */
> +	unsigned long long FAT2_start_sector; /* FAT2 start sector */
> +	unsigned long long root_start_sector; /* root dir start sector */
> +	unsigned long long data_start_sector; /* data area start sector */
> +	unsigned int num_FAT_sectors; /* num of FAT sectors */
> +	unsigned int root_dir; /* root dir cluster */
> +	unsigned int dentries_in_root; /* num of dentries in root dir */
> +	unsigned int dentries_per_clu; /* num of dentries per cluster */
> +	unsigned int vol_flag; /* volume dirty flag */
> +	struct buffer_head *pbr_bh; /* buffer_head of PBR sector */
> +
> +	unsigned int map_clu; /* allocation bitmap start cluster */
> +	unsigned int map_sectors; /* num of allocation bitmap sectors */
> +	struct buffer_head **vol_amap; /* allocation bitmap */
> +
> +	unsigned short *vol_utbl; /* upcase table */
> +
> +	unsigned int clu_srch_ptr; /* cluster search pointer */
> +	unsigned int used_clusters; /* number of used clusters */
> +
> +	bool s_dirt;
> +	struct mutex s_lock; /* superblock lock */
> +	struct super_block *host_sb; /* sb pointer */
> +	struct exfat_mount_options options;
> +	struct nls_table *nls_io; /* Charset used for input and display */
> +	struct ratelimit_state ratelimit;
> +
> +	spinlock_t inode_hash_lock;
> +	struct hlist_head inode_hashtable[EXFAT_HASH_SIZE];
> +};
> +
> +/*
> + * EXFAT file system inode in-memory data
> + */
> +struct exfat_inode_info {
> +	struct exfat_chain dir;
> +	int entry;
> +	unsigned int type;
> +	unsigned short attr;
> +	unsigned int start_clu;
> +	unsigned char flags;
> +	/*
> +	 * the copy of low 32bit of i_version to check
> +	 * the validation of hint_stat.
> +	 */
> +	unsigned int version;
> +	/* file offset or dentry index for readdir */
> +	loff_t rwoffset;
> +
> +	/* hint for cluster last accessed */
> +	struct exfat_hint hint_bmap;
> +	/* hint for entry index we try to lookup next time */
> +	struct exfat_hint hint_stat;
> +	/* hint for first empty entry */
> +	struct exfat_hint_femp hint_femp;
> +
> +	spinlock_t cache_lru_lock;
> +	struct list_head cache_lru;
> +	int nr_caches;
> +	/* for avoiding the race between alloc and free */
> +	unsigned int cache_valid_id;
> +
> +	/*
> +	 * NOTE: i_size_ondisk is 64bits, so must hold ->inode_lock to access.
> +	 * physically allocated size.
> +	 */
> +	loff_t i_size_ondisk;
> +	/* block-aligned i_size (used in cont_write_begin) */
> +	loff_t i_size_aligned;
> +	/* on-disk position of directory entry or 0 */
> +	loff_t i_pos;
> +	/* hash by i_location */
> +	struct hlist_node i_hash_fat;
> +	/* protect bmap against truncate */
> +	struct rw_semaphore truncate_lock;
> +	struct inode vfs_inode;
> +};
> +
> +static inline struct exfat_sb_info *EXFAT_SB(struct super_block *sb)
> +{
> +	return sb->s_fs_info;
> +}
> +
> +static inline struct exfat_inode_info *EXFAT_I(struct inode *inode)
> +{
> +	return container_of(inode, struct exfat_inode_info, vfs_inode);
> +}
> +
> +/*
> + * If ->i_mode can't hold 0222 (i.e. ATTR_RO), we use ->i_attrs to
> + * save ATTR_RO instead of ->i_mode.
> + *
> + * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
> + * bit, it's just used as flag for app.
> + */
> +static inline int exfat_mode_can_hold_ro(struct inode *inode)
> +{
> +	struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb);
> +
> +	if (S_ISDIR(inode->i_mode))
> +		return 0;
> +
> +	if ((~sbi->options.fs_fmask) & 0222)
> +		return 1;
> +	return 0;
> +}
> +
> +/* Convert attribute bits and a mask to the UNIX mode. */
> +static inline mode_t exfat_make_mode(struct exfat_sb_info *sbi,
> +		unsigned short attr, mode_t mode)
> +{
> +	if ((attr & ATTR_READONLY) && !(attr & ATTR_SUBDIR))
> +		mode &= ~0222;
> +
> +	if (attr & ATTR_SUBDIR)
> +		return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
> +
> +	return (mode & ~sbi->options.fs_fmask) | S_IFREG;
> +}
> +
> +/* Return the FAT attribute byte for this inode */
> +static inline unsigned short exfat_make_attr(struct inode *inode)
> +{
> +	unsigned short attr = EXFAT_I(inode)->attr;
> +
> +	if (S_ISDIR(inode->i_mode))
> +		attr |= ATTR_SUBDIR;
> +	if (exfat_mode_can_hold_ro(inode) && !(inode->i_mode & 0222))
> +		attr |= ATTR_READONLY;
> +	return attr;
> +}
> +
> +static inline void exfat_save_attr(struct inode *inode, unsigned short attr)
> +{
> +	if (exfat_mode_can_hold_ro(inode))
> +		EXFAT_I(inode)->attr = attr & (ATTR_RWMASK | ATTR_READONLY);
> +	else
> +		EXFAT_I(inode)->attr = attr & ATTR_RWMASK;
> +}
> +
> +static inline bool exfat_is_last_sector_in_cluster(struct exfat_sb_info *sbi,
> +		sector_t sec)
> +{
> +	return ((sec - sbi->data_start_sector + 1) &
> +			((1 << sbi->sect_per_clus_bits) - 1)) == 0;
> +}
> +
> +static inline sector_t exfat_cluster_to_sector(struct exfat_sb_info *sbi,
> +		unsigned int clus)
> +{
> +	return ((clus - BASE_CLUSTER) << sbi->sect_per_clus_bits)
> +			+ sbi->data_start_sector;
> +}
> +
> +static inline int exfat_sector_to_cluster(struct exfat_sb_info *sbi,
> +		sector_t sec)
> +{
> +	return ((sec - sbi->data_start_sector) >> sbi->sect_per_clus_bits) +
> +			BASE_CLUSTER;
> +}
> +
> +/* super.c */
> +int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flag);
> +
> +/* fatent.c */
> +#define exfat_get_next_cluster(sb, pclu) exfat_ent_get(sb, *(pclu), pclu)
> +
> +int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
> +		struct exfat_chain *p_chain);
> +int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain);
> +int exfat_ent_get(struct super_block *sb, unsigned int loc,
> +		unsigned int *content);
> +int exfat_ent_set(struct super_block *sb, unsigned int loc,
> +		unsigned int content);
> +int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
> +		int entry, struct exfat_dentry *p_entry);
> +int exfat_chain_cont_cluster(struct super_block *sb, unsigned int chain,
> +		unsigned int len);
> +struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
> +		struct exfat_chain *p_dir, int entry, struct buffer_head **bh,
> +		sector_t *sector);
> +struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
> +		struct exfat_chain *p_dir, int entry, unsigned int type,
> +		struct exfat_dentry **file_ep);
> +int exfat_zeroed_cluster(struct inode *dir, unsigned int clu);
> +int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
> +		int entry, sector_t *sector, int *offset);
> +int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain,
> +		unsigned int *ret_clu);
> +int exfat_mirror_bh(struct super_block *sb, sector_t sec,
> +		struct buffer_head *bh);
> +int exfat_count_num_clusters(struct super_block *sb,
> +		struct exfat_chain *p_chain, unsigned int *ret_count);
> +int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir);
> +
> +/* balloc.c */
> +int exfat_load_bitmap(struct super_block *sb);
> +void exfat_free_bitmap(struct super_block *sb);
> +int exfat_set_bitmap(struct inode *inode, unsigned int clu);
> +void exfat_clear_bitmap(struct inode *inode, unsigned int clu);
> +unsigned int exfat_test_bitmap(struct super_block *sb, unsigned int clu);
> +int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count);
> +
> +/* file.c */
> +extern const struct file_operations exfat_file_operations;
> +int __exfat_truncate(struct inode *inode, loff_t new_size);
> +void exfat_truncate(struct inode *inode, loff_t size);
> +int exfat_setattr(struct dentry *dentry, struct iattr *attr);
> +int exfat_getattr(const struct path *path, struct kstat *stat,
> +		unsigned int request_mask, unsigned int query_flags);
> +
> +/* namei.c */
> +extern const struct dentry_operations exfat_dentry_ops;
> +extern const struct dentry_operations exfat_ci_dentry_ops;
> +int exfat_find_empty_entry(struct inode *inode, struct exfat_chain *p_dir,
> +		int num_entries);
> +
> +/* cache.c */
> +int exfat_cache_init(void);
> +void exfat_cache_shutdown(void);
> +void exfat_cache_init_inode(struct inode *inode);
> +void exfat_cache_inval_inode(struct inode *inode);
> +int exfat_get_cluster(struct inode *inode, unsigned int cluster,
> +		unsigned int *fclus, unsigned int *dclus,
> +		unsigned int *last_dclus, int allow_eof);
> +
> +/* dir.c */
> +extern const struct inode_operations exfat_dir_inode_operations;
> +extern const struct file_operations exfat_dir_operations;
> +void exfat_get_uniname_from_ext_entry(struct super_block *sb,
> +		struct exfat_chain *p_dir, int entry, unsigned short *uniname);
> +unsigned int exfat_get_entry_type(struct exfat_dentry *p_entry);
> +void exfat_get_entry_time(struct exfat_dentry *p_entry,
> +		struct exfat_timestamp *tp, unsigned char mode);
> +void exfat_set_entry_time(struct exfat_dentry *p_entry,
> +		struct exfat_timestamp *tp, unsigned char mode);
> +int exfat_init_dir_entry(struct inode *inode, struct exfat_chain *p_dir,
> +		int entry, unsigned int type, unsigned int start_clu,
> +		unsigned long long size);
> +int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
> +		int entry, int num_entries, struct exfat_uni_name *p_uniname);
> +int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir,
> +		int entry, int order, int num_entries);
> +int update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
> +		int entry);
> +int exfat_update_dir_chksum_with_entry_set(struct super_block *sb,
> +		struct exfat_entry_set_cache *es, int sync);
> +int exfat_get_num_entries(struct exfat_uni_name *p_uniname);
> +int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
> +		struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
> +		int num_entries, unsigned int type);
> +int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu);
> +
> +/* inode.c */
> +extern const struct inode_operations exfat_file_inode_operations;
> +void exfat_sync_inode(struct inode *inode);
> +struct inode *exfat_build_inode(struct super_block *sb,
> +		struct exfat_dir_entry *info, loff_t i_pos);
> +void exfat_hash_inode(struct inode *inode, loff_t i_pos);
> +void exfat_unhash_inode(struct inode *inode);
> +void exfat_truncate(struct inode *inode, loff_t size);
> +struct inode *exfat_iget(struct super_block *sb, loff_t i_pos);
> +int exfat_write_inode(struct inode *inode, struct writeback_control *wbc);
> +void exfat_evict_inode(struct inode *inode);
> +int exfat_read_inode(struct inode *inode, struct exfat_dir_entry *info);
> +
> +/* exfat/nls.c */
> +int exfat_nls_cmp_uniname(struct super_block *sb, unsigned short *a,
> +		unsigned short *b);
> +int exfat_nls_uni16s_to_vfsname(struct super_block *sb,
> +		struct exfat_uni_name *uniname, unsigned char *p_cstring,
> +		int len);
> +int exfat_nls_vfsname_to_uni16s(struct super_block *sb,
> +		const unsigned char *p_cstring, const int len,
> +		struct exfat_uni_name *uniname, int *p_lossy);
> +int exfat_create_upcase_table(struct super_block *sb);
> +void exfat_free_upcase_table(struct super_block *sb);
> +
> +/* exfat/misc.c */
> +void __exfat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
> +		__printf(3, 4) __cold;
> +#define exfat_fs_error(sb, fmt, args...)          \
> +		__exfat_fs_error(sb, 1, fmt, ## args)
> +#define exfat_fs_error_ratelimit(sb, fmt, args...) \
> +		__exfat_fs_error(sb, __ratelimit(&EXFAT_SB(sb)->ratelimit), \
> +		fmt, ## args)
> +void exfat_msg(struct super_block *sb, const char *lv, const char *fmt, ...)
> +		__printf(3, 4) __cold;
> +void exfat_time_fat2unix(struct exfat_sb_info *sbi, struct timespec64 *ts,
> +		struct exfat_date_time *tp);
> +void exfat_time_unix2fat(struct exfat_sb_info *sbi, struct timespec64 *ts,
> +		struct exfat_date_time *tp);
> +struct exfat_timestamp *exfat_tm_now(struct exfat_sb_info *sbi,
> +		struct exfat_timestamp *tm);
> +unsigned short exfat_calc_chksum_2byte(void *data, int len,
> +		unsigned short chksum, int type);
> +void exfat_update_bh(struct super_block *sb, struct buffer_head *bh, int sync);
> +void exfat_chain_set(struct exfat_chain *ec, unsigned int dir,
> +		unsigned int size, unsigned char flags);

nit: You declare the function here and subsequent patches also use yet
it's not introduced until patch 8. This clearly will break the build
with only some patches applied of this series. This is likely not the
only offending function.

> +struct exfat_chain *exfat_chain_dup(struct exfat_chain *dir);
> +
> +#endif /* !_EXFAT_H */
> diff --git a/fs/exfat/exfat_raw.h b/fs/exfat/exfat_raw.h
> new file mode 100644
> index 000000000000..f40603992e0b
> --- /dev/null
> +++ b/fs/exfat/exfat_raw.h
> @@ -0,0 +1,190 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
> + */
> +
> +#ifndef _EXFAT_RAW_H
> +#define _EXFAT_RAW_H
> +
> +#include <linux/types.h>
> +
> +#define PBR_SIGNATURE		0xAA55
> +
> +#define VOL_CLEAN		0x0000
> +#define VOL_DIRTY		0x0002
> +
> +#define DENTRY_SIZE		32 /* directory entry size */
> +#define DENTRY_SIZE_BITS	5
> +/* exFAT allows 8388608(256MB) directory entries */
> +#define MAX_EXFAT_DENTRIES	8388608
> +
> +/* dentry types */
> +#define MSDOS_DELETED		0xE5	/* deleted mark */
> +#define MSDOS_UNUSED		0x00	/* end of directory */
> +
> +#define EXFAT_UNUSED		0x00	/* end of directory */
> +#define EXFAT_DELETE		~(0x80)
> +#define IS_EXFAT_DELETED(x)	((x) < 0x80) /* deleted file (0x01~0x7F) */
> +#define EXFAT_INVAL		0x80	/* invalid value */
> +#define EXFAT_BITMAP		0x81	/* allocation bitmap */
> +#define EXFAT_UPCASE		0x82	/* upcase table */
> +#define EXFAT_VOLUME		0x83	/* volume label */
> +#define EXFAT_FILE		0x85	/* file or dir */
> +#define EXFAT_GUID		0xA0
> +#define EXFAT_PADDING		0xA1
> +#define EXFAT_ACLTAB		0xA2
> +#define EXFAT_STREAM		0xC0	/* stream entry */
> +#define EXFAT_NAME		0xC1	/* file name entry */
> +#define EXFAT_ACL		0xC2	/* stream entry */
> +
> +/* checksum types */
> +#define CS_DIR_ENTRY		0
> +#define CS_PBR_SECTOR		1
> +#define CS_DEFAULT		2
> +
> +/* file attributes */
> +#define ATTR_READONLY		0x0001
> +#define ATTR_HIDDEN		0x0002
> +#define ATTR_SYSTEM		0x0004
> +#define ATTR_VOLUME		0x0008
> +#define ATTR_SUBDIR		0x0010
> +#define ATTR_ARCHIVE		0x0020
> +#define ATTR_EXTEND		(ATTR_READONLY | ATTR_HIDDEN | ATTR_SYSTEM | \
> +				 ATTR_VOLUME) /* 0x000F */
> +
> +#define ATTR_EXTEND_MASK	(ATTR_EXTEND | ATTR_SUBDIR | ATTR_ARCHIVE)
> +#define ATTR_RWMASK		(ATTR_HIDDEN | ATTR_SYSTEM | ATTR_VOLUME | \
> +				 ATTR_SUBDIR | ATTR_ARCHIVE)
> +
> +#define ATTR_READONLY_LE	cpu_to_le16(0x0001)
> +#define ATTR_HIDDEN_LE		cpu_to_le16(0x0002)
> +#define ATTR_SYSTEM_LE		cpu_to_le16(0x0004)
> +#define ATTR_VOLUME_LE		cpu_to_le16(0x0008)
> +#define ATTR_SUBDIR_LE		cpu_to_le16(0x0010)
> +#define ATTR_ARCHIVE_LE		cpu_to_le16(0x0020)
> +
> +/* EXFAT BIOS parameter block (64 bytes) */
> +struct bpb64 {
> +	__u8 jmp_boot[3];
> +	__u8 oem_name[8];
> +	__u8 res_zero[53];
> +};
> +
> +/* EXFAT EXTEND BIOS parameter block (56 bytes) */
> +struct bsx64 {
> +	__le64 vol_offset;
> +	__le64 vol_length;
> +	__le32 fat_offset;
> +	__le32 fat_length;
> +	__le32 clu_offset;
> +	__le32 clu_count;
> +	__le32 root_cluster;
> +	__le32 vol_serial;
> +	__u8 fs_version[2];
> +	__le16 vol_flags;
> +	__u8 sect_size_bits;
> +	__u8 sect_per_clus_bits;
> +	__u8 num_fats;
> +	__u8 phy_drv_no;
> +	__u8 perc_in_use;
> +	__u8 reserved2[7];
> +};
> +
> +/* EXFAT PBR[BPB+BSX] (120 bytes) */
> +struct pbr64 {
> +	struct bpb64 bpb;
> +	struct bsx64 bsx;
> +};
> +
> +/* Common PBR[Partition Boot Record] (512 bytes) */
> +struct pbr {
> +	union {
> +		__u8 raw[64];
> +		struct bpb64 f64;
> +	} bpb;
> +	union {
> +		__u8 raw[56];
> +		struct bsx64 f64;
> +	} bsx;
> +	__u8 boot_code[390];
> +	__le16 signature;
> +};
> +
> +struct exfat_dentry {
> +	__u8 type;
> +	union {
> +		struct {
> +			__u8 num_ext;
> +			__le16 checksum;
> +			__le16 attr;
> +			__le16 reserved1;
> +			__le16 create_time;
> +			__le16 create_date;
> +			__le16 modify_time;
> +			__le16 modify_date;
> +			__le16 access_time;
> +			__le16 access_date;
> +			__u8 create_time_ms;
> +			__u8 modify_time_ms;
> +			__u8 access_time_ms;
> +			__u8 reserved2[9];
> +		} __packed file; /* file directory entry */
> +		struct {
> +			__u8 flags;
> +			__u8 reserved1;
> +			__u8 name_len;
> +			__le16 name_hash;
> +			__le16 reserved2;
> +			__le64 valid_size;
> +			__le32 reserved3;
> +			__le32 start_clu;
> +			__le64 size;
> +		} __packed stream; /* stream extension directory entry */
> +		struct {
> +			__u8 flags;
> +			__le16 unicode_0_14[15];
> +		} __packed name; /* file name directory entry */
> +		struct {
> +			__u8 flags;
> +			__u8 reserved[18];
> +			__le32 start_clu;
> +			__le64 size;
> +		} __packed bitmap; /* allocation bitmap directory entry */
> +		struct {
> +			__u8 reserved1[3];
> +			__le32 checksum;
> +			__u8 reserved2[12];
> +			__le32 start_clu;
> +			__le64 size;
> +		} __packed upcase; /* up-case table directory entry */
> +	} __packed dentry;
> +} __packed;
> +
> +#define file_num_ext			dentry.file.num_ext
> +#define file_checksum			dentry.file.checksum
> +#define file_attr			dentry.file.attr
> +#define file_create_time		dentry.file.create_time
> +#define file_create_date		dentry.file.create_date
> +#define file_modify_time		dentry.file.modify_time
> +#define file_modify_date		dentry.file.modify_date
> +#define file_access_time		dentry.file.access_time
> +#define file_access_date		dentry.file.access_date
> +#define file_create_time_ms		dentry.file.create_time_ms
> +#define file_modify_time_ms		dentry.file.modify_time_ms
> +#define file_access_time_ms		dentry.file.access_time_ms
> +#define stream_flags			dentry.stream.flags
> +#define stream_name_len			dentry.stream.name_len
> +#define stream_name_hash		dentry.stream.name_hash
> +#define stream_start_clu		dentry.stream.start_clu
> +#define stream_valid_size		dentry.stream.valid_size
> +#define stream_size			dentry.stream.size
> +#define name_flags			dentry.name.flags
> +#define name_unicode			dentry.name.unicode_0_14
> +#define bitmap_flags			dentry.bitmap.flags
> +#define bitmap_start_clu		dentry.bitmap.start_clu
> +#define bitmap_size			dentry.bitmap.size
> +#define upcase_start_clu		dentry.upcase.start_clu
> +#define upcase_size			dentry.upcase.size
> +#define upcase_checksum			dentry.upcase.checksum
> +
> +#endif /* !_EXFAT_RAW_H */
>