ext3_fs.h

Go to the documentation of this file.

/*
 *  linux/include/linux/ext3_fs.h
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * 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_EXT3_FS_H
#define _LINUX_EXT3_FS_H

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/magic.h>

/*
 * The second extended filesystem constants/structures
 */

/*
 * Define EXT3FS_DEBUG to produce debug messages
 */
#undef EXT3FS_DEBUG

/*
 * Define EXT3_RESERVATION to reserve data blocks for expanding files
 */
#define EXT3_DEFAULT_RESERVE_BLOCKS     8
/*max window size: 1024(direct blocks) + 3([t,d]indirect blocks) */
#define EXT3_MAX_RESERVE_BLOCKS         1027
#define EXT3_RESERVE_WINDOW_NOT_ALLOCATED 0

/*
 * Debug code
 */
#ifdef EXT3FS_DEBUG
#define ext3_debug(f, a...)                     \
    do {                                \
        printk (KERN_DEBUG "EXT3-fs DEBUG (%s, %d): %s:",   \
            __FILE__, __LINE__, __FUNCTION__);      \
        printk (KERN_DEBUG f, ## a);                \
    } while (0)
#else
#define ext3_debug
#endif

/*
 * Special inodes numbers
 */
#define EXT3_BAD_INO         1  /* Bad blocks inode */
#define EXT3_ROOT_INO        2  /* Root inode */
#define EXT3_BOOT_LOADER_INO     5  /* Boot loader inode */
#define EXT3_UNDEL_DIR_INO   6  /* Undelete directory inode */
#define EXT3_RESIZE_INO      7  /* Reserved group descriptors inode */
#define EXT3_JOURNAL_INO     8  /* Journal inode */

/* First non-reserved inode for old ext3 filesystems */
#define EXT3_GOOD_OLD_FIRST_INO 11

/*
 * Maximal count of links to a file
 */
#define EXT3_LINK_MAX       32000

/*
 * Macro-instructions used to manage several block sizes
 */
#define EXT3_MIN_BLOCK_SIZE     1024
#define EXT3_MAX_BLOCK_SIZE     65536
#define EXT3_MIN_BLOCK_LOG_SIZE     10
#ifdef __KERNEL__
# define EXT3_BLOCK_SIZE(s)     ((s)->s_blocksize)
#else
# define EXT3_BLOCK_SIZE(s)     (EXT3_MIN_BLOCK_SIZE << (s)->s_log_block_size)
#endif
#define EXT3_ADDR_PER_BLOCK(s)      (EXT3_BLOCK_SIZE(s) / sizeof (__u32))
#ifdef __KERNEL__
# define EXT3_BLOCK_SIZE_BITS(s)    ((s)->s_blocksize_bits)
#else
# define EXT3_BLOCK_SIZE_BITS(s)    ((s)->s_log_block_size + 10)
#endif
#ifdef __KERNEL__
#define EXT3_ADDR_PER_BLOCK_BITS(s) (EXT3_SB(s)->s_addr_per_block_bits)
#define EXT3_INODE_SIZE(s)      (EXT3_SB(s)->s_inode_size)
#define EXT3_FIRST_INO(s)       (EXT3_SB(s)->s_first_ino)
#else
#define EXT3_INODE_SIZE(s)  (((s)->s_rev_level == EXT3_GOOD_OLD_REV) ? \
                 EXT3_GOOD_OLD_INODE_SIZE : \
                 (s)->s_inode_size)
#define EXT3_FIRST_INO(s)   (((s)->s_rev_level == EXT3_GOOD_OLD_REV) ? \
                 EXT3_GOOD_OLD_FIRST_INO : \
                 (s)->s_first_ino)
#endif

/*
 * Macro-instructions used to manage fragments
 */
#define EXT3_MIN_FRAG_SIZE      1024
#define EXT3_MAX_FRAG_SIZE      4096
#define EXT3_MIN_FRAG_LOG_SIZE        10
#ifdef __KERNEL__
# define EXT3_FRAG_SIZE(s)      (EXT3_SB(s)->s_frag_size)
# define EXT3_FRAGS_PER_BLOCK(s)    (EXT3_SB(s)->s_frags_per_block)
#else
# define EXT3_FRAG_SIZE(s)      (EXT3_MIN_FRAG_SIZE << (s)->s_log_frag_size)
# define EXT3_FRAGS_PER_BLOCK(s)    (EXT3_BLOCK_SIZE(s) / EXT3_FRAG_SIZE(s))
#endif

/*
 * Structure of a blocks group descriptor
 */
struct ext3_group_desc
{
    __le32  bg_block_bitmap;        /* Blocks bitmap block */
    __le32  bg_inode_bitmap;        /* Inodes bitmap block */
    __le32  bg_inode_table;     /* Inodes table block */
    __le16  bg_free_blocks_count;   /* Free blocks count */
    __le16  bg_free_inodes_count;   /* Free inodes count */
    __le16  bg_used_dirs_count; /* Directories count */
    __u16   bg_pad;
    __le32  bg_reserved[3];
};

/*
 * Structure of a blocks group descriptor
 */
struct ext4_group_desc
{
    __le32  bg_block_bitmap;    /* Blocks bitmap block */
    __le32  bg_inode_bitmap;    /* Inodes bitmap block */
    __le32  bg_inode_table; /* Inodes table block */
    __le16  bg_free_blocks_count;/* Free blocks count */
    __le16  bg_free_inodes_count;/* Free inodes count */
    __le16  bg_used_dirs_count; /* Directories count */
    __le16  bg_flags;       /* EXT4_BG_flags (INODE_UNINIT, etc) */
    __u32   bg_reserved[2];     /* Likely block/inode bitmap checksum */
    __le16  bg_itable_unused;   /* Unused inodes count */
    __le16  bg_checksum;        /* crc16(sb_uuid+group+desc) */
    __le32  bg_block_bitmap_hi; /* Blocks bitmap block MSB */
    __le32  bg_inode_bitmap_hi; /* Inodes bitmap block MSB */
    __le32  bg_inode_table_hi;  /* Inodes table block MSB */
    __le16  bg_free_blocks_count_hi;/* Free blocks count MSB */
    __le16  bg_free_inodes_count_hi;/* Free inodes count MSB */
    __le16  bg_used_dirs_count_hi;  /* Directories count MSB */
    __le16  bg_itable_unused_hi;    /* Unused inodes count MSB */
    __u32   bg_reserved2[3];
};

/*
 * Structure of a flex block group info
 */

struct flex_groups {
    __u32 free_inodes;
    __u32 free_blocks;
};

#define EXT4_BG_INODE_UNINIT    0x0001 /* Inode table/bitmap not in use */
#define EXT4_BG_BLOCK_UNINIT    0x0002 /* Block bitmap not in use */
#define EXT4_BG_INODE_ZEROED    0x0004 /* On-disk itable initialized to zero */

#define EXT4_MIN_BLOCK_SIZE     1024
#define EXT4_MIN_DESC_SIZE      32
#define EXT4_MIN_DESC_SIZE_64BIT    64
#define EXT4_MAX_DESC_SIZE      EXT4_MIN_BLOCK_SIZE

#define EXT4_DESC_SIZE(s)       (EXT3_SB(s)->s_desc_size)

/*
 * Macro-instructions used to manage group descriptors
 */
#ifdef __KERNEL__
# define EXT3_BLOCKS_PER_GROUP(s)   (EXT3_SB(s)->s_blocks_per_group)
# define EXT3_DESC_PER_BLOCK(s)     (EXT3_SB(s)->s_desc_per_block)
# define EXT3_INODES_PER_GROUP(s)   (EXT3_SB(s)->s_inodes_per_group)
# define EXT3_DESC_PER_BLOCK_BITS(s)    (EXT3_SB(s)->s_desc_per_block_bits)
# define EXT4_BLOCKS_PER_GROUP(s)   (EXT3_SB(s)->s_blocks_per_group)
# define EXT4_DESC_PER_BLOCK(s)     (EXT3_SB(s)->s_desc_per_block)
# define EXT4_INODES_PER_GROUP(s)   (EXT3_SB(s)->s_inodes_per_group)
# define EXT4_DESC_PER_BLOCK_BITS(s)    (EXT3_SB(s)->s_desc_per_block_bits)
#else
# define EXT3_BLOCKS_PER_GROUP(s)   ((s)->s_blocks_per_group)
# define EXT3_DESC_PER_BLOCK(s)     (EXT3_BLOCK_SIZE(s) / sizeof (struct ext3_group_desc))
# define EXT3_INODES_PER_GROUP(s)   ((s)->s_inodes_per_group)
#endif

/*
 * Constants relative to the data blocks
 */
#define EXT3_NDIR_BLOCKS        12
#define EXT3_IND_BLOCK          EXT3_NDIR_BLOCKS
#define EXT3_DIND_BLOCK         (EXT3_IND_BLOCK + 1)
#define EXT3_TIND_BLOCK         (EXT3_DIND_BLOCK + 1)
#define EXT3_N_BLOCKS           (EXT3_TIND_BLOCK + 1)

/*
 * Inode flags
 */
#define EXT3_SECRM_FL           0x00000001 /* Secure deletion */
#define EXT3_UNRM_FL            0x00000002 /* Undelete */
#define EXT3_COMPR_FL           0x00000004 /* Compress file */
#define EXT3_SYNC_FL            0x00000008 /* Synchronous updates */
#define EXT3_IMMUTABLE_FL       0x00000010 /* Immutable file */
#define EXT3_APPEND_FL          0x00000020 /* writes to file may only append */
#define EXT3_NODUMP_FL          0x00000040 /* do not dump file */
#define EXT3_NOATIME_FL         0x00000080 /* do not update atime */
/* Reserved for compression usage... */
#define EXT3_DIRTY_FL           0x00000100
#define EXT3_COMPRBLK_FL        0x00000200 /* One or more compressed clusters */
#define EXT3_NOCOMPR_FL         0x00000400 /* Don't compress */
#define EXT3_ECOMPR_FL          0x00000800 /* Compression error */
/* End compression flags --- maybe not all used */
#define EXT3_INDEX_FL           0x00001000 /* hash-indexed directory */
#define EXT3_IMAGIC_FL          0x00002000 /* AFS directory */
#define EXT3_JOURNAL_DATA_FL        0x00004000 /* file data should be journaled */
#define EXT3_NOTAIL_FL          0x00008000 /* file tail should not be merged */
#define EXT3_DIRSYNC_FL         0x00010000 /* dirsync behaviour (directories only) */
#define EXT3_TOPDIR_FL          0x00020000 /* Top of directory hierarchies*/
#define EXT3_RESERVED_FL        0x80000000 /* reserved for ext3 lib */

#define EXT3_FL_USER_VISIBLE        0x0003DFFF /* User visible flags */
#define EXT3_FL_USER_MODIFIABLE     0x000380FF /* User modifiable flags */

/*
 * Inode dynamic state flags
 */
#define EXT3_STATE_JDATA        0x00000001 /* journaled data exists */
#define EXT3_STATE_NEW          0x00000002 /* inode is newly created */
#define EXT3_STATE_XATTR        0x00000004 /* has in-inode xattrs */


/*
 * Ext4 Inode flags
 */
#define EXT4_SECRM_FL           0x00000001 /* Secure deletion */
#define EXT4_UNRM_FL            0x00000002 /* Undelete */
#define EXT4_COMPR_FL           0x00000004 /* Compress file */
#define EXT4_SYNC_FL            0x00000008 /* Synchronous updates */
#define EXT4_IMMUTABLE_FL       0x00000010 /* Immutable file */
#define EXT4_APPEND_FL          0x00000020 /* writes to file may only append */
#define EXT4_NODUMP_FL          0x00000040 /* do not dump file */
#define EXT4_NOATIME_FL         0x00000080 /* do not update atime */
/* Reserved for compression usage... */
#define EXT4_DIRTY_FL           0x00000100
#define EXT4_COMPRBLK_FL        0x00000200 /* One or more compressed clusters */
#define EXT4_NOCOMPR_FL         0x00000400 /* Don't compress */
#define EXT4_ECOMPR_FL          0x00000800 /* Compression error */
/* End compression flags --- maybe not all used */
#define EXT4_INDEX_FL           0x00001000 /* hash-indexed directory */
#define EXT4_IMAGIC_FL          0x00002000 /* AFS directory */
#define EXT4_JOURNAL_DATA_FL        0x00004000 /* file data should be journaled */
#define EXT4_NOTAIL_FL          0x00008000 /* file tail should not be merged */
#define EXT4_DIRSYNC_FL         0x00010000 /* dirsync behaviour (directories only) */
#define EXT4_TOPDIR_FL          0x00020000 /* Top of directory hierarchies*/
#define EXT4_HUGE_FILE_FL               0x00040000 /* Set to each huge file */
#define EXT4_EXTENTS_FL         0x00080000 /* Inode uses extents */
#define EXT4_EXT_MIGRATE        0x00100000 /* Inode is migrating */
#define EXT4_RESERVED_FL        0x80000000 /* reserved for ext4 lib */

#define EXT4_FL_USER_VISIBLE        0x000BDFFF /* User visible flags */
#define EXT4_FL_USER_MODIFIABLE     0x000B80FF /* User modifiable flags */

/* Used to pass group descriptor data when online resize is done */
struct ext3_new_group_input {
    __u32 group;            /* Group number for this data */
    __u32 block_bitmap;     /* Absolute block number of block bitmap */
    __u32 inode_bitmap;     /* Absolute block number of inode bitmap */
    __u32 inode_table;      /* Absolute block number of inode table start */
    __u32 blocks_count;     /* Total number of blocks in this group */
    __u16 reserved_blocks;  /* Number of reserved blocks in this group */
    __u16 unused;
};

/* The struct ext3_new_group_input in kernel space, with free_blocks_count */
struct ext3_new_group_data {
    __u32 group;
    __u32 block_bitmap;
    __u32 inode_bitmap;
    __u32 inode_table;
    __u32 blocks_count;
    __u16 reserved_blocks;
    __u16 unused;
    __u32 free_blocks_count;
};


/*
 * ioctl commands
 */
#define EXT3_IOC_GETFLAGS       FS_IOC_GETFLAGS
#define EXT3_IOC_SETFLAGS       FS_IOC_SETFLAGS
#define EXT3_IOC_GETVERSION     _IOR('f', 3, long)
#define EXT3_IOC_SETVERSION     _IOW('f', 4, long)
#define EXT3_IOC_GROUP_EXTEND       _IOW('f', 7, unsigned long)
#define EXT3_IOC_GROUP_ADD      _IOW('f', 8,struct ext3_new_group_input)
#define EXT3_IOC_GETVERSION_OLD     FS_IOC_GETVERSION
#define EXT3_IOC_SETVERSION_OLD     FS_IOC_SETVERSION
#ifdef CONFIG_JBD_DEBUG
#define EXT3_IOC_WAIT_FOR_READONLY  _IOR('f', 99, long)
#endif
#define EXT3_IOC_GETRSVSZ       _IOR('f', 5, long)
#define EXT3_IOC_SETRSVSZ       _IOW('f', 6, long)

/*
 * ioctl commands in 32 bit emulation
 */
#define EXT3_IOC32_GETFLAGS     FS_IOC32_GETFLAGS
#define EXT3_IOC32_SETFLAGS     FS_IOC32_SETFLAGS
#define EXT3_IOC32_GETVERSION       _IOR('f', 3, int)
#define EXT3_IOC32_SETVERSION       _IOW('f', 4, int)
#define EXT3_IOC32_GETRSVSZ     _IOR('f', 5, int)
#define EXT3_IOC32_SETRSVSZ     _IOW('f', 6, int)
#define EXT3_IOC32_GROUP_EXTEND     _IOW('f', 7, unsigned int)
#ifdef CONFIG_JBD_DEBUG
#define EXT3_IOC32_WAIT_FOR_READONLY    _IOR('f', 99, int)
#endif
#define EXT3_IOC32_GETVERSION_OLD   FS_IOC32_GETVERSION
#define EXT3_IOC32_SETVERSION_OLD   FS_IOC32_SETVERSION


/*
 *  Mount options
 */
struct ext3_mount_options {
    unsigned long s_mount_opt;
    uid_t s_resuid;
    gid_t s_resgid;
    unsigned long s_commit_interval;
#ifdef CONFIG_QUOTA
    int s_jquota_fmt;
    char *s_qf_names[MAXQUOTAS];
#endif
};

/*
 * Structure of an inode on the disk
 */
struct ext3_inode {
    __le16  i_mode;     /* File mode */
    __le16  i_uid;      /* Low 16 bits of Owner Uid */
    __le32  i_size;     /* Size in bytes */
    __le32  i_atime;    /* Access time */
    __le32  i_ctime;    /* Creation time */
    __le32  i_mtime;    /* Modification time */
    __le32  i_dtime;    /* Deletion Time */
    __le16  i_gid;      /* Low 16 bits of Group Id */
    __le16  i_links_count;  /* Links count */
    __le32  i_blocks;   /* Blocks count */
    __le32  i_flags;    /* File flags */
    union {
        struct {
            __le32  l_i_version;
        } linux1;
        struct {
            __u32  h_i_translator;
        } hurd1;
        struct {
            __u32  m_i_reserved1;
        } masix1;
    } osd1;             /* OS dependent 1 */
    __le32  i_block[EXT3_N_BLOCKS];/* Pointers to blocks */
    __le32  i_generation;   /* File version (for NFS) */
    __le32  i_file_acl_lo;  /* File ACL */
    __le32  i_size_high;
    __le32  i_obso_faddr;   /* Obsoleted fragment address */
    union {
        struct {
            __le16  l_i_blocks_high; /* were l_i_reserved1 */
            __le16  l_i_file_acl_high;
            __le16  l_i_uid_high;   /* these 2 fields */
            __le16  l_i_gid_high;   /* were reserved2[0] */
            __u32   l_i_reserved2;
        } linux2;
        struct {
            __le16  h_i_reserved1;  /* Obsoleted fragment number/size which are removed in ext4 */
            __u16   h_i_mode_high;
            __u16   h_i_uid_high;
            __u16   h_i_gid_high;
            __u32   h_i_author;
        } hurd2;
        struct {
            __le16  h_i_reserved1;  /* Obsoleted fragment number/size which are removed in ext4 */
            __le16  m_i_file_acl_high;
            __u32   m_i_reserved2[2];
        } masix2;
    } osd2;             /* OS dependent 2 */
    __le16  i_extra_isize;
    __le16  i_pad1;
    __le32  i_ctime_extra;  /* extra Change time      (nsec << 2 | epoch) */
    __le32  i_mtime_extra;  /* extra Modification time(nsec << 2 | epoch) */
    __le32  i_atime_extra;  /* extra Access time      (nsec << 2 | epoch) */
    __le32  i_crtime;       /* File Creation time */
    __le32  i_crtime_extra; /* extra FileCreationtime (nsec << 2 | epoch) */
    __le32  i_version_hi;   /* high 32 bits for 64-bit version */
};

#define i_disk_version osd1.linux1.l_i_version

#if defined(__KERNEL__) || defined(__linux__)
#define i_reserved1 osd1.linux1.l_i_reserved1
#define i_file_acl_high osd2.linux2.l_i_file_acl_high
#define i_blocks_high   osd2.linux2.l_i_blocks_high
#define i_uid_low   i_uid
#define i_gid_low   i_gid
#define i_uid_high  osd2.linux2.l_i_uid_high
#define i_gid_high  osd2.linux2.l_i_gid_high
#define i_reserved2 osd2.linux2.l_i_reserved2
#endif
/*
 * File system states
 */
#define EXT3_VALID_FS           0x0001  /* Unmounted cleanly */
#define EXT3_ERROR_FS           0x0002  /* Errors detected */
#define EXT3_ORPHAN_FS          0x0004  /* Orphans being recovered */

/*
 * Mount flags
 */
#define EXT3_MOUNT_CHECK        0x00001 /* Do mount-time checks */
#define EXT3_MOUNT_OLDALLOC     0x00002  /* Don't use the new Orlov allocator */
#define EXT3_MOUNT_GRPID        0x00004 /* Create files with directory's group */
#define EXT3_MOUNT_DEBUG        0x00008 /* Some debugging messages */
#define EXT3_MOUNT_ERRORS_CONT      0x00010 /* Continue on errors */
#define EXT3_MOUNT_ERRORS_RO        0x00020 /* Remount fs ro on errors */
#define EXT3_MOUNT_ERRORS_PANIC     0x00040 /* Panic on errors */
#define EXT3_MOUNT_MINIX_DF     0x00080 /* Mimics the Minix statfs */
#define EXT3_MOUNT_NOLOAD       0x00100 /* Don't use existing journal*/
#define EXT3_MOUNT_ABORT        0x00200 /* Fatal error detected */
#define EXT3_MOUNT_DATA_FLAGS       0x00C00 /* Mode for data writes: */
#define EXT3_MOUNT_JOURNAL_DATA     0x00400 /* Write data to journal */
#define EXT3_MOUNT_ORDERED_DATA     0x00800 /* Flush data before commit */
#define EXT3_MOUNT_WRITEBACK_DATA   0x00C00 /* No data ordering */
#define EXT3_MOUNT_UPDATE_JOURNAL   0x01000 /* Update the journal format */
#define EXT3_MOUNT_NO_UID32     0x02000  /* Disable 32-bit UIDs */
#define EXT3_MOUNT_XATTR_USER       0x04000 /* Extended user attributes */
#define EXT3_MOUNT_POSIX_ACL        0x08000 /* POSIX Access Control Lists */
#define EXT3_MOUNT_RESERVATION      0x10000 /* Preallocation */
#define EXT3_MOUNT_BARRIER      0x20000 /* Use block barriers */
#define EXT3_MOUNT_NOBH         0x40000 /* No bufferheads */
#define EXT3_MOUNT_QUOTA        0x80000 /* Some quota option set */
#define EXT3_MOUNT_USRQUOTA     0x100000 /* "old" user quota */
#define EXT3_MOUNT_GRPQUOTA     0x200000 /* "old" group quota */

/* Compatibility, for having both ext2_fs.h and ext3_fs.h included at once */
#ifndef _LINUX_EXT2_FS_H
#define clear_opt(o, opt)       o &= ~EXT3_MOUNT_##opt
#define set_opt(o, opt)         o |= EXT3_MOUNT_##opt
#define test_opt(sb, opt)       (EXT3_SB(sb)->s_mount_opt & \
                     EXT3_MOUNT_##opt)
#else
#define EXT2_MOUNT_NOLOAD       EXT3_MOUNT_NOLOAD
#define EXT2_MOUNT_ABORT        EXT3_MOUNT_ABORT
#define EXT2_MOUNT_DATA_FLAGS       EXT3_MOUNT_DATA_FLAGS
#endif

#define ext3_set_bit            ext2_set_bit
#define ext3_set_bit_atomic     ext2_set_bit_atomic
#define ext3_clear_bit          ext2_clear_bit
#define ext3_clear_bit_atomic       ext2_clear_bit_atomic
#define ext3_test_bit           ext2_test_bit
#define ext3_find_first_zero_bit    ext2_find_first_zero_bit
#define ext3_find_next_zero_bit     ext2_find_next_zero_bit

/*
 * Maximal mount counts between two filesystem checks
 */
#define EXT3_DFL_MAX_MNT_COUNT      20  /* Allow 20 mounts */
#define EXT3_DFL_CHECKINTERVAL      0   /* Don't use interval check */

/*
 * Behaviour when detecting errors
 */
#define EXT3_ERRORS_CONTINUE        1   /* Continue execution */
#define EXT3_ERRORS_RO          2   /* Remount fs read-only */
#define EXT3_ERRORS_PANIC       3   /* Panic */
#define EXT3_ERRORS_DEFAULT     EXT3_ERRORS_CONTINUE

/*
 * Structure of the super block
 */
struct ext3_super_block {
    /*00*/
    __le32  s_inodes_count;     /* Inodes count */
    __le32  s_blocks_count; /* Blocks count */
    __le32  s_r_blocks_count;   /* Reserved blocks count */
    __le32  s_free_blocks_count;    /* Free blocks count */
    /*10*/
    __le32  s_free_inodes_count;    /* Free inodes count */
    __le32  s_first_data_block; /* First Data Block */
    __le32  s_log_block_size;   /* Block size */
    __le32  s_obso_log_frag_size;   /* Obsoleted fragment size */
    /*20*/
    __le32  s_blocks_per_group; /* # Blocks per group */
    __le32  s_obso_frags_per_group; /* Obsoleted fragments per group */
    __le32  s_inodes_per_group; /* # Inodes per group */
    __le32  s_mtime;        /* Mount time */
    /*30*/
    __le32  s_wtime;        /* Write time */
    __le16  s_mnt_count;        /* Mount count */
    __le16  s_max_mnt_count;    /* Maximal mount count */
    __le16  s_magic;        /* Magic signature */
    __le16  s_state;        /* File system state */
    __le16  s_errors;       /* Behaviour when detecting errors */
    __le16  s_minor_rev_level;  /* minor revision level */
    /*40*/
    __le32  s_lastcheck;        /* time of last check */
    __le32  s_checkinterval;    /* max. time between checks */
    __le32  s_creator_os;       /* OS */
    __le32  s_rev_level;        /* Revision level */
    /*50*/
    __le16  s_def_resuid;       /* Default uid for reserved blocks */
    __le16  s_def_resgid;       /* Default gid for reserved blocks */
    /*
     * These fields are for EXT4_DYNAMIC_REV superblocks only.
     *
     * Note: the difference between the compatible feature set and
     * the incompatible feature set is that if there is a bit set
     * in the incompatible feature set that the kernel doesn't
     * know about, it should refuse to mount the filesystem.
     *
     * e2fsck's requirements are more strict; if it doesn't know
     * about a feature in either the compatible or incompatible
     * feature set, it must abort and not try to meddle with
     * things it doesn't understand...
     */
    __le32  s_first_ino;        /* First non-reserved inode */
    __le16  s_inode_size;       /* size of inode structure */
    __le16  s_block_group_nr;   /* block group # of this superblock */
    __le32  s_feature_compat;   /* compatible feature set */
    /*60*/
    __le32  s_feature_incompat; /* incompatible feature set */
    __le32  s_feature_ro_compat;    /* readonly-compatible feature set */
    /*68*/
    __u8    s_uuid[16];     /* 128-bit uuid for volume */
    /*78*/
    char    s_volume_name[16];  /* volume name */
    /*88*/
    char    s_last_mounted[64]; /* directory where last mounted */
    /*C8*/
    __le32  s_algorithm_usage_bitmap; /* For compression */
    /*
     * Performance hints.  Directory preallocation should only
     * happen if the EXT4_FEATURE_COMPAT_DIR_PREALLOC flag is on.
     */
    __u8    s_prealloc_blocks;  /* Nr of blocks to try to preallocate*/
    __u8    s_prealloc_dir_blocks;  /* Nr to preallocate for dirs */
    __le16  s_reserved_gdt_blocks;  /* Per group desc for online growth */
    /*
     * Journaling support valid if EXT4_FEATURE_COMPAT_HAS_JOURNAL set.
     */
    /*D0*/
    __u8    s_journal_uuid[16]; /* uuid of journal superblock */
    /*E0*/
    __le32  s_journal_inum;     /* inode number of journal file */
    __le32  s_journal_dev;      /* device number of journal file */
    __le32  s_last_orphan;      /* start of list of inodes to delete */
    __le32  s_hash_seed[4];     /* HTREE hash seed */
    __u8    s_def_hash_version; /* Default hash version to use */
    __u8    s_reserved_char_pad;
    __le16  s_desc_size;        /* size of group descriptor */
    /*100*/
    __le32  s_default_mount_opts;
    __le32  s_first_meta_bg;    /* First metablock block group */
    __le32  s_mkfs_time;        /* When the filesystem was created */
    __le32  s_jnl_blocks[17];   /* Backup of the journal inode */
    /* 64bit support valid if EXT4_FEATURE_COMPAT_64BIT */
    /*150*/
    __le32  s_blocks_count_hi;  /* Blocks count */
    __le32  s_r_blocks_count_hi;    /* Reserved blocks count */
    __le32  s_free_blocks_count_hi; /* Free blocks count */
    __le16  s_min_extra_isize;  /* All inodes have at least # bytes */
    __le16  s_want_extra_isize;     /* New inodes should reserve # bytes */
    __le32  s_flags;        /* Miscellaneous flags */
    __le16  s_raid_stride;      /* RAID stride */
    __le16  s_mmp_interval;         /* # seconds to wait in MMP checking */
    __le64  s_mmp_block;            /* Block for multi-mount protection */
    __le32  s_raid_stripe_width;    /* blocks on all data disks (N*stride)*/
    __u8    s_log_groups_per_flex;  /* FLEX_BG group size */
    __u8    s_reserved_char_pad2;
    __le16  s_reserved_pad;
    __u32   s_reserved[162];        /* Padding to the end of the block */
};

#ifdef __KERNEL__
#include <linux/ext3_fs_i.h>
#include <linux/ext3_fs_sb.h>
static inline struct ext3_sb_info * EXT3_SB(struct super_block *sb)
{
    return sb->s_fs_info;
}
static inline struct inode *EXT3_I(struct inode *inode)
{
    return inode;
}

static inline int ext3_valid_inum(struct super_block *sb, unsigned long ino)
{
    return ino == EXT3_ROOT_INO ||
           ino == EXT3_JOURNAL_INO ||
           ino == EXT3_RESIZE_INO ||
           (ino >= EXT3_FIRST_INO(sb) &&
            ino <= le32_to_cpu(EXT3_SB(sb)->s_es->s_inodes_count));
}
#else
/* Assume that user mode programs are passing in an ext3fs superblock, not
 * a kernel struct super_block.  This will allow us to call the feature-test
 * macros from user land. */
#define EXT3_SB(sb) (sb)
#endif


#define NEXT_ORPHAN(inode) EXT3_I(inode)->i_dtime

/*
 * Codes for operating systems
 */
#define EXT3_OS_LINUX       0
#define EXT3_OS_HURD        1
#define EXT3_OS_MASIX       2
#define EXT3_OS_FREEBSD     3
#define EXT3_OS_LITES       4

/*
 * Revision levels
 */
#define EXT3_GOOD_OLD_REV   0   /* The good old (original) format */
#define EXT3_DYNAMIC_REV    1   /* V2 format w/ dynamic inode sizes */

#define EXT3_CURRENT_REV    EXT3_GOOD_OLD_REV
#define EXT3_MAX_SUPP_REV   EXT3_DYNAMIC_REV

#define EXT3_GOOD_OLD_INODE_SIZE 128

/*
 * Feature set definitions
 */

#define EXT3_HAS_COMPAT_FEATURE(sb,mask)            \
    ( EXT3_SB(sb)->s_es->s_feature_compat & cpu_to_le32(mask) )
#define EXT3_HAS_RO_COMPAT_FEATURE(sb,mask)         \
    ( EXT3_SB(sb)->s_es->s_feature_ro_compat & cpu_to_le32(mask) )
#define EXT3_HAS_INCOMPAT_FEATURE(sb,mask)          \
    ( EXT3_SB(sb)->s_es->s_feature_incompat & cpu_to_le32(mask) )
#define EXT3_SET_COMPAT_FEATURE(sb,mask)            \
    EXT3_SB(sb)->s_es->s_feature_compat |= cpu_to_le32(mask)
#define EXT3_SET_RO_COMPAT_FEATURE(sb,mask)         \
    EXT3_SB(sb)->s_es->s_feature_ro_compat |= cpu_to_le32(mask)
#define EXT3_SET_INCOMPAT_FEATURE(sb,mask)          \
    EXT3_SB(sb)->s_es->s_feature_incompat |= cpu_to_le32(mask)
#define EXT3_CLEAR_COMPAT_FEATURE(sb,mask)          \
    EXT3_SB(sb)->s_es->s_feature_compat &= ~cpu_to_le32(mask)
#define EXT3_CLEAR_RO_COMPAT_FEATURE(sb,mask)           \
    EXT3_SB(sb)->s_es->s_feature_ro_compat &= ~cpu_to_le32(mask)
#define EXT3_CLEAR_INCOMPAT_FEATURE(sb,mask)            \
    EXT3_SB(sb)->s_es->s_feature_incompat &= ~cpu_to_le32(mask)

#define EXT3_FEATURE_COMPAT_DIR_PREALLOC    0x0001
#define EXT3_FEATURE_COMPAT_IMAGIC_INODES   0x0002
#define EXT3_FEATURE_COMPAT_HAS_JOURNAL     0x0004
#define EXT3_FEATURE_COMPAT_EXT_ATTR        0x0008
#define EXT3_FEATURE_COMPAT_RESIZE_INODE    0x0010
#define EXT3_FEATURE_COMPAT_DIR_INDEX       0x0020

#define EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001
#define EXT3_FEATURE_RO_COMPAT_LARGE_FILE   0x0002
#define EXT3_FEATURE_RO_COMPAT_BTREE_DIR    0x0004
#define EXT4_FEATURE_RO_COMPAT_GDT_CSUM     0x0010
#define EXT4_FEATURE_RO_COMPAT_DIR_NLINK    0x0020
#define EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE  0x0040

#define EXT3_FEATURE_INCOMPAT_COMPRESSION   0x0001
#define EXT3_FEATURE_INCOMPAT_FILETYPE      0x0002
#define EXT3_FEATURE_INCOMPAT_RECOVER       0x0004 /* Needs recovery */
#define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV   0x0008 /* Journal device */
#define EXT3_FEATURE_INCOMPAT_META_BG       0x0010
#define EXT3_FEATURE_INCOMPAT_EXTENTS       0x0040 /* extents support */
#define EXT3_FEATURE_INCOMPAT_MMP           0x0100
#define EXT3_FEATURE_INCOMPAT_DIRDATA       0x1000

#define EXT3_FEATURE_COMPAT_SUPP    EXT2_FEATURE_COMPAT_EXT_ATTR

#define EXT4_FEATURE_COMPAT_DIR_PREALLOC    0x0001
#define EXT4_FEATURE_COMPAT_IMAGIC_INODES   0x0002
#define EXT4_FEATURE_COMPAT_HAS_JOURNAL     0x0004
#define EXT4_FEATURE_COMPAT_EXT_ATTR        0x0008
#define EXT4_FEATURE_COMPAT_RESIZE_INODE    0x0010
#define EXT4_FEATURE_COMPAT_DIR_INDEX       0x0020

#define EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001
#define EXT4_FEATURE_RO_COMPAT_LARGE_FILE   0x0002
#define EXT4_FEATURE_RO_COMPAT_BTREE_DIR    0x0004
#define EXT4_FEATURE_RO_COMPAT_HUGE_FILE    0x0008
#define EXT4_FEATURE_RO_COMPAT_GDT_CSUM     0x0010
#define EXT4_FEATURE_RO_COMPAT_DIR_NLINK    0x0020
#define EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE  0x0040

#define EXT4_FEATURE_INCOMPAT_COMPRESSION   0x0001
#define EXT4_FEATURE_INCOMPAT_FILETYPE      0x0002
#define EXT4_FEATURE_INCOMPAT_RECOVER       0x0004 /* Needs recovery */
#define EXT4_FEATURE_INCOMPAT_JOURNAL_DEV   0x0008 /* Journal device */
#define EXT4_FEATURE_INCOMPAT_META_BG       0x0010
#define EXT4_FEATURE_INCOMPAT_EXTENTS       0x0040 /* extents support */
#define EXT4_FEATURE_INCOMPAT_64BIT         0x0080
#define EXT4_FEATURE_INCOMPAT_MMP           0x0100
#define EXT4_FEATURE_INCOMPAT_FLEX_BG       0x0200
#define EXT4_FEATURE_INCOMPAT_DIRDATA       0x1000  /* used by Lustre - ldiskfs */
#define EXT4_FEATURE_INCOMPAT_BG_USE_META_CSUM  0x2000 /* use crc32c for bg */
#define EXT4_FEATURE_INCOMPAT_LARGEDIR      0x4000 /* >2GB or 3-lvl htree */
#define EXT4_FEATURE_INCOMPAT_INLINEDATA    0x8000 /* data in inode */

#define EXT4_FEATURE_INCOMPAT_SUPP  (                       \
                    EXT4_FEATURE_INCOMPAT_FILETYPE|         \
                    EXT4_FEATURE_INCOMPAT_RECOVER|          \
                    EXT4_FEATURE_INCOMPAT_META_BG|          \
                    EXT4_FEATURE_INCOMPAT_EXTENTS|          \
                    EXT4_FEATURE_INCOMPAT_FLEX_BG)
#define EXT4_FEATURE_RO_COMPAT_SUPP (                       \
                    EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER|    \
                    EXT4_FEATURE_RO_COMPAT_LARGE_FILE|      \
                    EXT4_FEATURE_RO_COMPAT_GDT_CSUM|        \
                    EXT4_FEATURE_RO_COMPAT_DIR_NLINK |      \
                    EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE |    \
                    EXT4_FEATURE_RO_COMPAT_BTREE_DIR |      \
                    EXT4_FEATURE_RO_COMPAT_HUGE_FILE)

#define EXT4_BG_INODE_UNINIT    0x0001 /* Inode table/bitmap not in use */
#define EXT4_BG_BLOCK_UNINIT    0x0002 /* Block bitmap not in use */
#define EXT4_BG_INODE_ZEROED    0x0004 /* On-disk itable initialized to zero */

/*
 * Default values for user and/or group using reserved blocks
 */
#define EXT3_DEF_RESUID     0
#define EXT3_DEF_RESGID     0

/*
 * Default mount options
 */
#define EXT3_DEFM_DEBUG     0x0001
#define EXT3_DEFM_BSDGROUPS 0x0002
#define EXT3_DEFM_XATTR_USER    0x0004
#define EXT3_DEFM_ACL       0x0008
#define EXT3_DEFM_UID16     0x0010
#define EXT3_DEFM_JMODE     0x0060
#define EXT3_DEFM_JMODE_DATA    0x0020
#define EXT3_DEFM_JMODE_ORDERED 0x0040
#define EXT3_DEFM_JMODE_WBACK   0x0060

/*
 * Structure of a directory entry
 */
#define EXT3_NAME_LEN 255

struct ext3_dir_entry {
    __le32  inode;          /* Inode number */
    __le16  rec_len;        /* Directory entry length */
    __le16  name_len;       /* Name length */
    char    name[EXT3_NAME_LEN];    /* File name */
};

/*
 * The new version of the directory entry.  Since EXT3 structures are
 * stored in intel byte order, and the name_len field could never be
 * bigger than 255 chars, it's safe to reclaim the extra byte for the
 * file_type field.
 */
struct ext3_dir_entry_2 {
    __le32  inode;          /* Inode number */
    __le16  rec_len;        /* Directory entry length */
    __u8    name_len;       /* Name length */
    __u8    file_type;
    char    name[EXT3_NAME_LEN];    /* File name */
};

/*
 * Ext3 directory file types.  Only the low 3 bits are used.  The
 * other bits are reserved for now.
 */
#define EXT3_FT_UNKNOWN     0
#define EXT3_FT_REG_FILE    1
#define EXT3_FT_DIR     2
#define EXT3_FT_CHRDEV      3
#define EXT3_FT_BLKDEV      4
#define EXT3_FT_FIFO        5
#define EXT3_FT_SOCK        6
#define EXT3_FT_SYMLINK     7

#define EXT3_FT_MAX     8
#define EXT3_FT_MASK        0xf

#if EXT3_FT_MAX > EXT3_FT_MASK
#error "conflicting EXT3_FT_MAX and EXT3_FT_MASK"
#endif

#define EXT3_LUFID_MAGIC    0xAD200907UL

#pragma pack(1)
struct ext3_dentry_param {
    __u32  edp_magic;       /* EXT3_LUFID_MAGIC */
    char   edp_len;         /* size of edp_data in bytes */
    char   edp_data[0];     /* packed array of data */
} __attribute__((packed));
#pragma pack()

static inline unsigned char *ext3_dentry_get_data(struct super_block *sb,
        struct ext3_dentry_param* p)

{
    if (!EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_DIRDATA))
        return NULL;
    if (p && p->edp_magic == EXT3_LUFID_MAGIC)
        return &p->edp_len;
    else
        return NULL;
}

/*
 * Compute the total directory entry data length.
 * This includes the filename and an implicit NUL terminator (always present),
 * and optional extensions.  Each extension has a bit set in the high 4 bits of
 * de->file_type, and the extension length is the first byte in each entry.
 */

static inline int ext3_get_dirent_data_len(struct ext3_dir_entry_2 *de)
{
    char *len = de->name + de->name_len + 1 /* NUL terminator */;
    int dlen = 0;
    __u8 extra_data_flags = (de->file_type & ~EXT3_FT_MASK) >> 4;

    while (extra_data_flags) {
        if (extra_data_flags & 1) {
            dlen += *len + (dlen == 0);
            len += *len;
        }
        extra_data_flags >>= 1;
    }
    return dlen;
}

/*
 * d_type has 4 unused bits, so it can hold four types data. these different
 * type of data (e.g. lustre data, high 32 bits of 64-bit inode number) can be
 * stored, in flag order, after file-name in ext3 dirent.
*/
/*
 * this flag is added to d_type if ext3 dirent has extra data after
 * filename. this data length is variable and length is stored in first byte
 * of data. data start after filename NUL byte.
 * This is used by Lustre FS.
 */

#define EXT3_DIRENT_LUFID       0x10
/*
 * EXT3_DIR_PAD defines the directory entries boundaries
 *
 * NOTE: It must be a multiple of 4
 */
#define EXT3_DIR_PAD            4
#define EXT3_DIR_ROUND          (EXT3_DIR_PAD - 1)
#define EXT3_DIR_REC_LEN(len)   (((len) + 8 + EXT3_DIR_ROUND) & \
                                 ~EXT3_DIR_ROUND)
#define EXT3_MAX_REC_LEN        ((1<<16)-1)

static inline unsigned ext3_rec_len_from_disk(__le16 dlen)
{
    unsigned len = le16_to_cpu(dlen);

    if (len == EXT3_MAX_REC_LEN || len == 0)
        return 1 << 16;
    return len;
}

static inline __le16 ext3_rec_len_to_disk(unsigned len)
{
    if (len == (1 << 16))
        return cpu_to_le16(EXT3_MAX_REC_LEN);
    else if (len > (1 << 16))
        BUG();
    return cpu_to_le16(len);
}

/*
 * Hash Tree Directory indexing
 * (c) Daniel Phillips, 2001
 */

#ifdef EXT2_HTREE_INDEX
#define is_dx(dir) (EXT3_HAS_COMPAT_FEATURE(dir->i_sb, \
                          EXT3_FEATURE_COMPAT_DIR_INDEX) && \
              (EXT3_I(dir)->i_flags & EXT3_INDEX_FL))
#define EXT3_DIR_LINK_MAX(dir) (!is_dx(dir) && (dir)->i_nlink >= EXT3_LINK_MAX)
#define EXT3_DIR_LINK_EMPTY(dir) ((dir)->i_nlink == 2 || (dir)->i_nlink == 1)
#else
#define is_dx(dir) 0
#define EXT3_DIR_LINK_MAX(dir) ((dir)->i_nlink >= EXT3_LINK_MAX)
#define EXT3_DIR_LINK_EMPTY(dir) ((dir)->i_nlink == 2)
#endif

/* Legal values for the dx_root hash_version field: */

#define DX_HASH_LEGACY              0
#define DX_HASH_HALF_MD4            1
#define DX_HASH_TEA                 2
#define DX_HASH_LEGACY_UNSIGNED     3
#define DX_HASH_HALF_MD4_UNSIGNED   4
#define DX_HASH_TEA_UNSIGNED        5


#ifdef __KERNEL__

/* hash info structure used by the directory hash */
struct dx_hash_info
{
    u32     hash;
    u32     minor_hash;
    int     hash_version;
    u32     *seed;
};

#define EXT3_HTREE_EOF  0x7fffffff

/* 32 and 64 bit signed EOF for dx directories */
#define EXT4_HTREE_EOF_32BIT   ((1UL  << (32 - 1)) - 1)
#define EXT4_HTREE_EOF_64BIT   ((1ULL << (64 - 1)) - 1

/*
 * Control parameters used by ext3_htree_next_block
 */
#define HASH_NB_ALWAYS      1


/*
 * Describe an inode's exact location on disk and in memory
 */
struct ext3_iloc
{
    struct buffer_head *bh;
    unsigned long offset;
    unsigned long block_group;
};

static inline struct ext3_inode *ext3_raw_inode(struct ext3_iloc *iloc)
{
    return (struct ext3_inode *) (iloc->bh->b_data + iloc->offset);
}

/*
 * This structure is stuffed into the struct file's private_data field
 * for directories.  It is where we put information so that we can do
 * readdir operations in hash tree order.
 */
struct dir_private_info {
    struct rb_root  root;
    struct rb_node  *curr_node;
    struct fname    *extra_fname;
    loff_t      last_pos;
    __u32       curr_hash;
    __u32       curr_minor_hash;
    __u32       next_hash;
};

/* calculate the first block number of the group */
static inline ext3_fsblk_t
ext3_group_first_block_no(struct super_block *sb, unsigned long group_no)
{
    return group_no * (ext3_fsblk_t)EXT3_BLOCKS_PER_GROUP(sb) +
           le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block);
}

/*
 * Special error return code only used by dx_probe() and its callers.
 */
#define ERR_BAD_DX_DIR  -75000

/*
 * This structure will be used for multiple mount protection. It will be
 * written into the block number saved in the s_mmp_block field in the
 * superblock. Programs that check MMP should assume that if
 * SEQ_FSCK (or any unknown code above SEQ_MAX) is present then it is NOT safe
 * to use the filesystem, regardless of how old the timestamp is.
 */
#define EXT3_MMP_MAGIC     0x004D4D50U /* ASCII for MMP */
#define EXT3_MMP_SEQ_CLEAN 0xFF4D4D50U /* mmp_seq value for clean unmount */
#define EXT3_MMP_SEQ_FSCK  0xE24D4D50U /* mmp_seq value when being fscked */
#define EXT3_MMP_SEQ_MAX   0xE24D4D4FU /* maximum valid mmp_seq value */

struct mmp_struct {
    __le32  mmp_magic;
    __le32  mmp_seq;
    __le64  mmp_time;
    char    mmp_nodename[64];
    char    mmp_bdevname[32];
    __le16  mmp_check_interval;
    __le16  mmp_pad1;
    __le32  mmp_pad2[227];
};

/*
 * Default interval in seconds to update the MMP sequence number.
 */
#define EXT3_MMP_UPDATE_INTERVAL   1

/*
 * Minimum interval for MMP checking in seconds.
 */
#define EXT3_MMP_MIN_CHECK_INTERVAL 5

/*
 * Indicates that ctime should not be updated in ext3_xattr_set_handle()
 */
#ifndef XATTR_NO_CTIME
#define XATTR_NO_CTIME 0x80
#endif

/*
 * NOTE! unlike strncmp, ext3_match returns 1 for success, 0 for failure.
 *
 * `len <= EXT3_NAME_LEN' is guaranteed by caller.
 * `de != NULL' is guaranteed by caller.
 */
static inline int ext3_match (int len, const char * const name,
                              struct ext3_dir_entry_2 * de)
{
    if (len != de->name_len)
        return 0;
    if (!de->inode)
        return 0;
    return !_strnicmp(name, de->name, len);
}

#endif  /* __KERNEL__ */
#endif  /* _LINUX_EXT3_FS_H */