ext2_fs.h

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/**
*

 *  linux/include/linux/ext2_fs.h
 *
 *  Copyright (C) 1992, 1993, 1994  Remy Card (card@masi.ibp.fr)
 *                                  Laboratoire MASI - Institut Blaise Pascal
 *                                  Universite Pierre et Marie Curie (Paris VI)
 *
 *  from
 *
 *  linux/include/linux/minix_fs.h
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds


*/

#ifndef _LINUX_EXT2_FS_H
#define _LINUX_EXT2_FS_H

/**
*

 * The second extended filesystem constants/structures


*/

/**
*

 * Define EXT2FS_DEBUG to produce debug messages


*/
#undef EXT2FS_DEBUG

/**
*

 * Define EXT2FS_DEBUG_CACHE to produce cache debug messages


*/
#undef EXT2FS_DEBUG_CACHE

/**
*

 * Define EXT2FS_CHECK_CACHE to add some checks to the name cache code


*/
#undef EXT2FS_CHECK_CACHE

/**
*

 * Define EXT2FS_PRE_02B_COMPAT to convert ext 2 fs prior to 0.2b


*/
#undef EXT2FS_PRE_02B_COMPAT

/**
*

 * Define DONT_USE_DCACHE to inhibit the directory cache


*/
#define DONT_USE_DCACHE

/**
*

 * Define EXT2_PREALLOCATE to preallocate data blocks for expanding files


*/
#define EXT2_PREALLOCATE

/**
*

 * The second extended file system version


*/
#define EXT2FS_DATE             "94/03/10"
#define EXT2FS_VERSION          "0.5"

/**
*

 * Debug code


*/
#ifdef EXT2FS_DEBUG
#       define ext2_debug(f, a...)      { \
                                        printk ("EXT2-fs DEBUG (%s, %d): %s:", \
                                                __FILE__, __LINE__, __FUNCTION__); \
                                        printk (f, ## a); \
                                        }
#else
#       define ext2_debug(f, a...)      ///<
#endif

/**
*

 * Special inodes numbers


*/
#define EXT2_BAD_INO             1      ///< Bad blocks inode 
#define EXT2_ROOT_INO            2      ///< Root inode 
#define EXT2_ACL_IDX_INO         3      ///< ACL inode 
#define EXT2_ACL_DATA_INO        4      ///< ACL inode 
#define EXT2_BOOT_LOADER_INO     5      ///< Boot loader inode 
#define EXT2_UNDEL_DIR_INO       6      ///< Undelete directory inode 
#define EXT2_FIRST_INO          11      ///< First non reserved inode 

/**
*

 * The second extended file system magic number


*/
#define EXT2_PRE_02B_MAGIC      0xEF51
#define EXT2_SUPER_MAGIC        0xEF53

/**
*

 * Maximal count of links to a file


*/
#define EXT2_LINK_MAX           32000

/**
*

 * Macro-instructions used to manage several block sizes


*/
#define EXT2_MIN_BLOCK_SIZE             1024
#define EXT2_MAX_BLOCK_SIZE             4096
#define EXT2_MIN_BLOCK_LOG_SIZE           10
#ifdef __KERNEL__
# define EXT2_BLOCK_SIZE(s)             ((s)->s_blocksize)
#else
# define EXT2_BLOCK_SIZE(s)             (EXT2_MIN_BLOCK_SIZE << (s)->s_log_block_size)
#endif
#define EXT2_ACLE_PER_BLOCK(s)          (EXT2_BLOCK_SIZE(s) / sizeof (struct ext2_acl_entry))
#define EXT2_ADDR_PER_BLOCK(s)          (EXT2_BLOCK_SIZE(s) / sizeof (unsigned long))
#ifdef __KERNEL__
# define EXT2_BLOCK_SIZE_BITS(s)        ((s)->u.ext2_sb.s_es->s_log_block_size + 10)
#else
# define EXT2_BLOCK_SIZE_BITS(s)        ((s)->s_log_block_size + 10)
#endif
#define EXT2_INODES_PER_BLOCK(s)        (EXT2_BLOCK_SIZE(s) / sizeof (struct ext2_inode))

/**
*

 * Macro-instructions used to manage fragments


*/
#define EXT2_MIN_FRAG_SIZE              1024
#define EXT2_MAX_FRAG_SIZE              4096
#define EXT2_MIN_FRAG_LOG_SIZE            10
#ifdef __KERNEL__
# define EXT2_FRAG_SIZE(s)              ((s)->u.ext2_sb.s_frag_size)
# define EXT2_FRAGS_PER_BLOCK(s)        ((s)->u.ext2_sb.s_frags_per_block)
#else
# define EXT2_FRAG_SIZE(s)              (EXT2_MIN_FRAG_SIZE << (s)->s_log_frag_size)
# define EXT2_FRAGS_PER_BLOCK(s)        (EXT2_BLOCK_SIZE(s) / EXT2_FRAG_SIZE(s))
#endif

/**
*

 * ACL structures


*/
struct ext2_acl_header  ///< Header of Access Control Lists 
{
        unsigned long aclh_size;
        unsigned long aclh_file_count;
        unsigned long aclh_acle_count;
        unsigned long aclh_first_acle;
};

struct ext2_acl_entry   ///< Access Control List Entry 
{
        unsigned long  acle_size;
        unsigned short acle_perms;      ///< Access permissions 
        unsigned short acle_type;       ///< Type of entry 
        unsigned short acle_tag;        ///< User or group identity 
        unsigned short acle_pad1;
        unsigned long  acle_next;       ///< Pointer on next entry for the 
                                        /// same inode or on next free entry 
};

/**
*

 * Structure of a blocks group descriptor


*/
struct ext2_old_group_desc
{
        unsigned long  bg_block_bitmap;         ///< Blocks bitmap block 
        unsigned long  bg_inode_bitmap;         ///< Inodes bitmap block 
        unsigned long  bg_inode_table;          ///< Inodes table block 
        unsigned short bg_free_blocks_count;    ///< Free blocks count 
        unsigned short bg_free_inodes_count;    ///< Free inodes count 
};

struct ext2_group_desc
{
        unsigned long  bg_block_bitmap;         ///< Blocks bitmap block 
        unsigned long  bg_inode_bitmap;         ///< Inodes bitmap block 
        unsigned long  bg_inode_table;          ///< Inodes table block 
        unsigned short bg_free_blocks_count;    ///< Free blocks count 
        unsigned short bg_free_inodes_count;    ///< Free inodes count 
        unsigned short bg_used_dirs_count;      ///< Directories count 
        unsigned short bg_pad;
        unsigned long  bg_reserved[3];
};

/**
*

 * Macro-instructions used to manage group descriptors


*/
#ifdef __KERNEL__
# define EXT2_BLOCKS_PER_GROUP(s)       ((s)->u.ext2_sb.s_blocks_per_group)
# define EXT2_DESC_PER_BLOCK(s)         ((s)->u.ext2_sb.s_desc_per_block)
# define EXT2_INODES_PER_GROUP(s)       ((s)->u.ext2_sb.s_inodes_per_group)
#else
# define EXT2_BLOCKS_PER_GROUP(s)       ((s)->s_blocks_per_group)
# define EXT2_DESC_PER_BLOCK(s)         (EXT2_BLOCK_SIZE(s) / sizeof (struct ext2_group_desc))
# define EXT2_INODES_PER_GROUP(s)       ((s)->s_inodes_per_group)
#endif

/**
*

 * Constants relative to the data blocks


*/
#define EXT2_NDIR_BLOCKS                12
#define EXT2_IND_BLOCK                  EXT2_NDIR_BLOCKS
#define EXT2_DIND_BLOCK                 (EXT2_IND_BLOCK + 1)
#define EXT2_TIND_BLOCK                 (EXT2_DIND_BLOCK + 1)
#define EXT2_N_BLOCKS                   (EXT2_TIND_BLOCK + 1)

/**
*

 * Inode flags


*/
#define EXT2_SECRM_FL                   0x0001  ///< Secure deletion 
#define EXT2_UNRM_FL                    0x0002  ///< Undelete 
#define EXT2_COMPR_FL                   0x0004  ///< Compress file 
#define EXT2_SYNC_FL                    0x0008  ///< Synchronous updates 

/**
*

 * ioctl commands


*/
#define EXT2_IOC_GETFLAGS               _IOR('f', 1, long)
#define EXT2_IOC_SETFLAGS               _IOW('f', 2, long)
#define EXT2_IOC_GETVERSION             _IOR('v', 1, long)
#define EXT2_IOC_SETVERSION             _IOW('v', 2, long)

/**
*

 * Structure of an inode on the disk


*/
struct ext2_inode {
        unsigned short i_mode;          ///< File mode 
        unsigned short i_uid;           ///< Owner Uid 
        unsigned long  i_size;          ///< Size in bytes 
        unsigned long  i_atime;         ///< Access time 
        unsigned long  i_ctime;         ///< Creation time 
        unsigned long  i_mtime;         ///< Modification time 
        unsigned long  i_dtime;         ///< Deletion Time 
        unsigned short i_gid;           ///< Group Id 
        unsigned short i_links_count;   ///< Links count 
        unsigned long  i_blocks;        ///< Blocks count 
        unsigned long  i_flags;         ///< File flags 
        unsigned long  i_reserved1;
        unsigned long  i_block[EXT2_N_BLOCKS];///< Pointers to blocks 
        unsigned long  i_version;       ///< File version (for NFS) 
        unsigned long  i_file_acl;      ///< File ACL 
        unsigned long  i_dir_acl;       ///< Directory ACL 
        unsigned long  i_faddr;         ///< Fragment address 
        unsigned char  i_frag;          ///< Fragment number 
        unsigned char  i_fsize;         ///< Fragment size 
        unsigned short i_pad1;
        unsigned long  i_reserved2[2];
};

/**
*

 * File system states


*/
#define EXT2_VALID_FS                   0x0001  ///< Unmounted cleany 
#define EXT2_ERROR_FS                   0x0002  ///< Errors detected 

/**
*

 * Mount flags


*/
#define EXT2_MOUNT_CHECK_NORMAL         0x0001  ///< Do some more checks 
#define EXT2_MOUNT_CHECK_STRICT         0x0002  ///< Do again more checks 
#define EXT2_MOUNT_CHECK                (EXT2_MOUNT_CHECK_NORMAL | \
                                         EXT2_MOUNT_CHECK_STRICT)
#define EXT2_MOUNT_GRPID                0x0004  ///< Create files with directory's group 
#define EXT2_MOUNT_DEBUG                0x0008  ///< Some debugging messages 
#define EXT2_MOUNT_ERRORS_CONT          0x0010  ///< Continue on errors 
#define EXT2_MOUNT_ERRORS_RO            0x0020  ///< Remount fs ro on errors 
#define EXT2_MOUNT_ERRORS_PANIC         0x0040  ///< Panic on errors 

#define clear_opt(o, opt)               o &= ~EXT2_MOUNT_##opt
#define set_opt(o, opt)                 o |= EXT2_MOUNT_##opt
#define test_opt(sb, opt)               ((sb)->u.ext2_sb.s_mount_opt & \
                                         EXT2_MOUNT_##opt)
/**
*

 * Maximal mount counts between two filesystem checks


*/
#define EXT2_DFL_MAX_MNT_COUNT          20      ///< Allow 20 mounts 
#define EXT2_DFL_CHECKINTERVAL          0       ///< Don't use interval check 

/**
*

 * Behaviour when detecting errors


*/
#define EXT2_ERRORS_CONTINUE            1       ///< Continue execution 
#define EXT2_ERRORS_RO                  2       ///< Remount fs read-only 
#define EXT2_ERRORS_PANIC               3       ///< Panic 
#define EXT2_ERRORS_DEFAULT             EXT2_ERRORS_CONTINUE

/**
*

 * Structure of the super block


*/
struct ext2_super_block {
        unsigned long  s_inodes_count;  ///< Inodes count 
        unsigned long  s_blocks_count;  ///< Blocks count 
        unsigned long  s_r_blocks_count;///< Reserved blocks count 
        unsigned long  s_free_blocks_count;///< Free blocks count 
        unsigned long  s_free_inodes_count;///< Free inodes count 
        unsigned long  s_first_data_block;///< First Data Block 
        unsigned long  s_log_block_size;///< Block size 
        long           s_log_frag_size; ///< Fragment size 
        unsigned long  s_blocks_per_group;///< # Blocks per group 
        unsigned long  s_frags_per_group;///< # Fragments per group 
        unsigned long  s_inodes_per_group;///< # Inodes per group 
        unsigned long  s_mtime;         ///< Mount time 
        unsigned long  s_wtime;         ///< Write time 
        unsigned short s_mnt_count;     ///< Mount count 
        short          s_max_mnt_count; ///< Maximal mount count 
        unsigned short s_magic;         ///< Magic signature 
        unsigned short s_state;         ///< File system state 
        unsigned short s_errors;        ///< Behaviour when detecting errors 
        unsigned short s_pad;
        unsigned long  s_lastcheck;     ///< time of last check 
        unsigned long  s_checkinterval; ///< max. time between checks 
        unsigned long  s_reserved[238]; ///< Padding to the end of the block 
};

/**
*

 * Structure of a directory entry


*/
#define EXT2_NAME_LEN 255

struct ext2_dir_entry {
        unsigned long  inode;                   ///< Inode number 
        unsigned short rec_len;                 ///< Directory entry length 
        unsigned short name_len;                ///< Name length 
        char           name[EXT2_NAME_LEN];     ///< File name 
};

/**
*

 * EXT2_DIR_PAD defines the directory entries boundaries
 *
 * NOTE: It must be a multiple of 4


*/
#define EXT2_DIR_PAD                    4
#define EXT2_DIR_ROUND                  (EXT2_DIR_PAD - 1)
#define EXT2_DIR_REC_LEN(name_len)      (((name_len) + 8 + EXT2_DIR_ROUND) & \
                                         ~EXT2_DIR_ROUND)

#ifdef __KERNEL__
/**
*

 * Function prototypes


*/

/**
*

 * Ok, these declarations are also in <linux/kernel.h> but none of the
 * ext2 source programs needs to include it so they are duplicated here.


*/
#if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 5)
# define NORET_TYPE    __volatile__
# define ATTRIB_NORET  ///<
# define NORET_AND     ///<
#else
# define NORET_TYPE    ///<
# define ATTRIB_NORET  __attribute__((noreturn))
# define NORET_AND     noreturn,
#endif

/// acl.c 
extern int ext2_permission (struct inode *, int);

/// balloc.c 
extern int ext2_new_block (struct super_block *, unsigned long,
                           unsigned long *, unsigned long *);
extern void ext2_free_blocks (struct super_block *, unsigned long,
                              unsigned long);
extern unsigned long ext2_count_free_blocks (struct super_block *);
extern void ext2_check_blocks_bitmap (struct super_block *);

/// bitmap.c 
extern unsigned long ext2_count_free (struct buffer_head *, unsigned);

#ifndef DONT_USE_DCACHE
/// dcache.c 
extern void ext2_dcache_invalidate (unsigned short);
extern unsigned long ext2_dcache_lookup (unsigned short, unsigned long,
                                         const char *, int);
extern void ext2_dcache_add (unsigned short, unsigned long, const char *,
                             int, unsigned long);
extern void ext2_dcache_remove (unsigned short, unsigned long, const char *,
                                int);
#endif

/// dir.c 
extern int ext2_check_dir_entry (char *, struct inode *,
                                 struct ext2_dir_entry *, struct buffer_head *,
                                 unsigned long);

/// file.c 
extern int ext2_read (struct inode *, struct file *, char *, int);
extern int ext2_write (struct inode *, struct file *, char *, int);

/// fsync.c 
extern int ext2_sync_file (struct inode *, struct file *);

/// ialloc.c 
extern struct inode * ext2_new_inode (const struct inode *, int);
extern void ext2_free_inode (struct inode *);
extern unsigned long ext2_count_free_inodes (struct super_block *);
extern void ext2_check_inodes_bitmap (struct super_block *);

/// inode.c 
extern int ext2_bmap (struct inode *, int);

extern struct buffer_head * ext2_getblk (struct inode *, long, int, int *);
extern struct buffer_head * ext2_bread (struct inode *, int, int, int *);

extern void ext2_read_inode (struct inode *);
extern void ext2_write_inode (struct inode *);
extern void ext2_put_inode (struct inode *);
extern int ext2_sync_inode (struct inode *);
extern void ext2_discard_prealloc (struct inode *);

/// ioctl.c 
extern int ext2_ioctl (struct inode *, struct file *, unsigned int,
                       unsigned long);

/// namei.c 
extern int ext2_open (struct inode *, struct file *);
extern void ext2_release (struct inode *, struct file *);
extern int ext2_lookup (struct inode *,const char *, int, struct inode **);
extern int ext2_create (struct inode *,const char *, int, int,
                        struct inode **);
extern int ext2_mkdir (struct inode *, const char *, int, int);
extern int ext2_rmdir (struct inode *, const char *, int);
extern int ext2_unlink (struct inode *, const char *, int);
extern int ext2_symlink (struct inode *, const char *, int, const char *);
extern int ext2_link (struct inode *, struct inode *, const char *, int);
extern int ext2_mknod (struct inode *, const char *, int, int, int);
extern int ext2_rename (struct inode *, const char *, int,
                        struct inode *, const char *, int);

/// super.c 
extern void ext2_error (struct super_block *, const char *, const char *, ...)
        __attribute__ ((format (printf, 3, 4)));
extern NORET_TYPE void ext2_panic (struct super_block *, const char *,
                                   const char *, ...)
        __attribute__ ((NORET_AND format (printf, 3, 4)));
extern void ext2_warning (struct super_block *, const char *, const char *, ...)
        __attribute__ ((format (printf, 3, 4)));
extern void ext2_put_super (struct super_block *);
extern void ext2_write_super (struct super_block *);
extern int ext2_remount (struct super_block *, int *, char *);
extern struct super_block * ext2_read_super (struct super_block *,void *,int);
extern void ext2_statfs (struct super_block *, struct statfs *);

/// truncate.c 
extern void ext2_truncate (struct inode *);

/**
*

 * Inodes and files operations


*/

/// dir.c 
extern struct inode_operations ext2_dir_inode_operations;

/// file.c 
extern struct inode_operations ext2_file_inode_operations;

/// symlink.c 
extern struct inode_operations ext2_symlink_inode_operations;

#endif  // __KERNEL__ 

#endif  // _LINUX_EXT2_FS_H 

---