text: /* SPDX-License-Identifier: GPL-2.0 */
  #include <linux/buffer_head.h>
  #include <linux/fs.h>
  #include <linux/adfs_fs.h>
  
  /* Internal data structures for ADFS */
  
  #define ADFS_FREE_FRAG		 0
  #define ADFS_BAD_FRAG		 1
  #define ADFS_ROOT_FRAG		 2
  
  #define ADFS_FILETYPE_NONE	((u16)~0)
  
  /* RISC OS 12-bit filetype is stored in load_address[19:8] */
  static inline u16 adfs_filetype(u32 loadaddr)
  {
  	return (loadaddr & 0xfff00000) == 0xfff00000 ?
  	       (loadaddr >> 8) & 0xfff : ADFS_FILETYPE_NONE;
  }
  
  #define ADFS_NDA_OWNER_READ	(1 << 0)
  #define ADFS_NDA_OWNER_WRITE	(1 << 1)
  #define ADFS_NDA_LOCKED		(1 << 2)
  #define ADFS_NDA_DIRECTORY	(1 << 3)
  #define ADFS_NDA_EXECUTE	(1 << 4)
  #define ADFS_NDA_PUBLIC_READ	(1 << 5)
  #define ADFS_NDA_PUBLIC_WRITE	(1 << 6)
  
  #include "dir_f.h"
  
  /*
   * adfs file system inode data in memory
   */
  struct adfs_inode_info {
  	loff_t		mmu_private;
  	__u32		parent_id;	/* parent indirect disc address	*/
  	__u32		loadaddr;	/* RISC OS load address		*/
  	__u32		execaddr;	/* RISC OS exec address		*/
  	unsigned int	attr;		/* RISC OS permissions		*/
  	struct inode vfs_inode;
  };
  
  static inline struct adfs_inode_info *ADFS_I(struct inode *inode)
  {
  	return container_of(inode, struct adfs_inode_info, vfs_inode);
  }
  
  static inline bool adfs_inode_is_stamped(struct inode *inode)
  {
  	return (ADFS_I(inode)->loadaddr & 0xfff00000) == 0xfff00000;
  }
  
  /*
   * Forward-declare this
   */
  struct adfs_discmap;
  struct adfs_dir_ops;
  
  /*
   * ADFS file system superblock data in memory
   */
  struct adfs_sb_info {
  	union { struct {
  		struct adfs_discmap *s_map;	/* bh list containing map */
  		const struct adfs_dir_ops *s_dir; /* directory operations */
  		};
  		struct rcu_head rcu;	/* used only at shutdown time	 */
  	};
  	kuid_t		s_uid;		/* owner uid */
  	kgid_t		s_gid;		/* owner gid */
  	umode_t		s_owner_mask;	/* ADFS owner perm -> unix perm */
  	umode_t		s_other_mask;	/* ADFS other perm -> unix perm	*/
  	int		s_ftsuffix;	/* ,xyz hex filetype suffix option */
  
  	__u32		s_ids_per_zone;	/* max. no ids in one zone */
  	__u32		s_idlen;	/* length of ID in map */
  	__u32		s_map_size;	/* sector size of a map	*/
  	signed int	s_map2blk;	/* shift left by this for map->sector*/
  	unsigned int	s_log2sharesize;/* log2 share size */
  	unsigned int	s_namelen;	/* maximum number of characters in name	 */
  };
  
  static inline struct adfs_sb_info *ADFS_SB(struct super_block *sb)
  {
  	return sb->s_fs_info;
  }
  
  /*
   * Directory handling
   */
  struct adfs_dir {
  	struct super_block	*sb;
  
  	int			nr_buffers;
  	struct buffer_head	*bh[4];
  
  	/* big directories need allocated buffers */
  	struct buffer_head	**bh_fplus;
  
  	unsigned int		pos;
  	__u32			parent_id;
  
  	struct adfs_dirheader	dirhead;
  	union  adfs_dirtail	dirtail;
  };
  
  /*
   * This is the overall maximum name length
   */
  #define ADFS_MAX_NAME_LEN	(256 + 4) /* +4 for ,xyz hex filetype suffix */
  struct object_info {
  	__u32		parent_id;		/* parent object id	*/
  	__u32		indaddr;		/* indirect disc addr	*/
  	__u32		loadaddr;		/* load address		*/
  	__u32		execaddr;		/* execution address	*/
  	__u32		size;			/* size			*/
  	__u8		attr;			/* RISC OS attributes	*/
  	unsigned int	name_len;		/* name length		*/
  	char		name[ADFS_MAX_NAME_LEN];/* file name		*/
  };
  
  struct adfs_dir_ops {
  	int	(*read)(struct super_block *sb, unsigned int indaddr,
  			unsigned int size, struct adfs_dir *dir);
  	int	(*setpos)(struct adfs_dir *dir, unsigned int fpos);
  	int	(*getnext)(struct adfs_dir *dir, struct object_info *obj);
  	int	(*update)(struct adfs_dir *dir, struct object_info *obj);
  	int	(*create)(struct adfs_dir *dir, struct object_info *obj);
  	int	(*remove)(struct adfs_dir *dir, struct object_info *obj);
  	int	(*sync)(struct adfs_dir *dir);
  	void	(*free)(struct adfs_dir *dir);
  };
  
  struct adfs_discmap {
  	struct buffer_head	*dm_bh;
  	__u32			dm_startblk;
  	unsigned int		dm_startbit;
  	unsigned int		dm_endbit;
  };
  
  /* Inode stuff */
  struct inode *adfs_iget(struct super_block *sb, struct object_info *obj);
  int adfs_write_inode(struct inode *inode, struct writeback_control *wbc);
  int adfs_notify_change(struct dentry *dentry, struct iattr *attr);
  
  /* map.c */
  int adfs_map_lookup(struct super_block *sb, u32 frag_id, unsigned int offset);
  extern unsigned int adfs_map_free(struct super_block *sb);
  
  /* Misc */
  __printf(3, 4)
  void __adfs_error(struct super_block *sb, const char *function,
  		  const char *fmt, ...);
  #define adfs_error(sb, fmt...) __adfs_error(sb, __func__, fmt)
  void adfs_msg(struct super_block *sb, const char *pfx, const char *fmt, ...);
  
  /* super.c */
  
  /*
   * Inodes and file operations
   */
  
  /* dir_*.c */
  extern const struct inode_operations adfs_dir_inode_operations;
  extern const struct file_operations adfs_dir_operations;
  extern const struct dentry_operations adfs_dentry_operations;
  extern const struct adfs_dir_ops adfs_f_dir_ops;
  extern const struct adfs_dir_ops adfs_fplus_dir_ops;
  
  void adfs_object_fixup(struct adfs_dir *dir, struct object_info *obj);
  extern int adfs_dir_update(struct super_block *sb, struct object_info *obj,
  			   int wait);
  
  /* file.c */
  extern const struct inode_operations adfs_file_inode_operations;
  extern const struct file_operations adfs_file_operations;
  
  static inline __u32 signed_asl(__u32 val, signed int shift)
  {
  	if (shift >= 0)
  		val <<= shift;
  	else
  		val >>= -shift;
  	return val;
  }
  
  /*
   * Calculate the address of a block in an object given the block offset
   * and the object identity.
   *
   * The root directory ID should always be looked up in the map [3.4]
   */
  static inline int __adfs_block_map(struct super_block *sb, u32 indaddr,
  				   unsigned int block)
  {
  	if (indaddr & 255) {
  		unsigned int off;
  
  		off = (indaddr & 255) - 1;
  		block += off << ADFS_SB(sb)->s_log2sharesize;
  	}
  
  	return adfs_map_lookup(sb, indaddr >> 8, block);
  }
  
  /* Return the disc record from the map */
  static inline
  struct adfs_discrecord *adfs_map_discrecord(struct adfs_discmap *dm)
  {
  	return (void *)(dm[0].dm_bh->b_data + 4);
  }
  
  static inline u64 adfs_disc_size(const struct adfs_discrecord *dr)
  {
  	return (u64)le32_to_cpu(dr->disc_size_high) << 32 |
  		    le32_to_cpu(dr->disc_size);
  }
  