os/linux-2.6-tag--devboard-R2_10-4/include/linux/ext2_fs.h

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/*
 *  linux/include/linux/ext2_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_EXT2_FS_H
#define _LINUX_EXT2_FS_H

#include <linux/types.h>
#include <linux/magic.h>

#if defined(CONFIG_ETRAX_ARCH_V32) || defined(CONFIG_ETRAX_ARCH_V10)
#include <asm-generic/bitops/ext2-non-atomic.h>
#endif

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

/*
 * Define EXT2FS_DEBUG to produce debug messages
 */
#undef EXT2FS_DEBUG

/*
 * Define EXT2_PREALLOCATE to preallocate data blocks for expanding files
 */
#define EXT2_PREALLOCATE
#define EXT2_DEFAULT_PREALLOC_BLOCKS    8

/*
 * The second extended file system version
 */
#define EXT2FS_DATE             "95/08/09"
#define EXT2FS_VERSION          "0.5b"

/*
 * 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 inode numbers
 */
#define EXT2_BAD_INO             1      /* Bad blocks inode */
#define EXT2_ROOT_INO            2      /* Root inode */
#define EXT2_BOOT_LOADER_INO     5      /* Boot loader inode */
#define EXT2_UNDEL_DIR_INO       6      /* Undelete directory inode */

/* First non-reserved inode for old ext2 filesystems */
#define EXT2_GOOD_OLD_FIRST_INO 11

#ifdef __KERNEL__
#include <linux/ext2_fs_sb.h>
static inline struct ext2_sb_info *EXT2_SB(struct super_block *sb)
{
        return sb->s_fs_info;
}
#else
/* Assume that user mode programs are passing in an ext2fs superblock, not
 * a kernel struct super_block.  This will allow us to call the feature-test
 * macros from user land. */
#define EXT2_SB(sb)     (sb)
#endif

/*
 * 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_ADDR_PER_BLOCK(s)          (EXT2_BLOCK_SIZE(s) / sizeof (__u32))
#ifdef __KERNEL__
# define EXT2_BLOCK_SIZE_BITS(s)        ((s)->s_blocksize_bits)
#else
# define EXT2_BLOCK_SIZE_BITS(s)        ((s)->s_log_block_size + 10)
#endif
#ifdef __KERNEL__
#define EXT2_ADDR_PER_BLOCK_BITS(s)     (EXT2_SB(s)->s_addr_per_block_bits)
#define EXT2_INODE_SIZE(s)              (EXT2_SB(s)->s_inode_size)
#define EXT2_FIRST_INO(s)               (EXT2_SB(s)->s_first_ino)
#else
#define EXT2_INODE_SIZE(s)      (((s)->s_rev_level == EXT2_GOOD_OLD_REV) ? \
                                 EXT2_GOOD_OLD_INODE_SIZE : \
                                 (s)->s_inode_size)
#define EXT2_FIRST_INO(s)       (((s)->s_rev_level == EXT2_GOOD_OLD_REV) ? \
                                 EXT2_GOOD_OLD_FIRST_INO : \
                                 (s)->s_first_ino)
#endif

/*
 * 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)              (EXT2_SB(s)->s_frag_size)
# define EXT2_FRAGS_PER_BLOCK(s)        (EXT2_SB(s)->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

/*
 * Structure of a blocks group descriptor
 */
struct ext2_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_pad;
        __le32  bg_reserved[3];
};

/*
 * Macro-instructions used to manage group descriptors
 */
#ifdef __KERNEL__
# define EXT2_BLOCKS_PER_GROUP(s)       (EXT2_SB(s)->s_blocks_per_group)
# define EXT2_DESC_PER_BLOCK(s)         (EXT2_SB(s)->s_desc_per_block)
# define EXT2_INODES_PER_GROUP(s)       (EXT2_SB(s)->s_inodes_per_group)
# define EXT2_DESC_PER_BLOCK_BITS(s)    (EXT2_SB(s)->s_desc_per_block_bits)
#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 (GETFLAGS/SETFLAGS)
 */
#define EXT2_SECRM_FL                   FS_SECRM_FL     /* Secure deletion */
#define EXT2_UNRM_FL                    FS_UNRM_FL      /* Undelete */
#define EXT2_COMPR_FL                   FS_COMPR_FL     /* Compress file */
#define EXT2_SYNC_FL                    FS_SYNC_FL      /* Synchronous updates */
#define EXT2_IMMUTABLE_FL               FS_IMMUTABLE_FL /* Immutable file */
#define EXT2_APPEND_FL                  FS_APPEND_FL    /* writes to file may only append */
#define EXT2_NODUMP_FL                  FS_NODUMP_FL    /* do not dump file */
#define EXT2_NOATIME_FL                 FS_NOATIME_FL   /* do not update atime */
/* Reserved for compression usage... */
#define EXT2_DIRTY_FL                   FS_DIRTY_FL
#define EXT2_COMPRBLK_FL                FS_COMPRBLK_FL  /* One or more compressed clusters */
#define EXT2_NOCOMP_FL                  FS_NOCOMP_FL    /* Don't compress */
#define EXT2_ECOMPR_FL                  FS_ECOMPR_FL    /* Compression error */
/* End compression flags --- maybe not all used */      
#define EXT2_BTREE_FL                   FS_BTREE_FL     /* btree format dir */
#define EXT2_INDEX_FL                   FS_INDEX_FL     /* hash-indexed directory */
#define EXT2_IMAGIC_FL                  FS_IMAGIC_FL    /* AFS directory */
#define EXT2_JOURNAL_DATA_FL            FS_JOURNAL_DATA_FL /* Reserved for ext3 */
#define EXT2_NOTAIL_FL                  FS_NOTAIL_FL    /* file tail should not be merged */
#define EXT2_DIRSYNC_FL                 FS_DIRSYNC_FL   /* dirsync behaviour (directories only) */
#define EXT2_TOPDIR_FL                  FS_TOPDIR_FL    /* Top of directory hierarchies*/
#define EXT2_RESERVED_FL                FS_RESERVED_FL  /* reserved for ext2 lib */

#define EXT2_FL_USER_VISIBLE            FS_FL_USER_VISIBLE      /* User visible flags */
#define EXT2_FL_USER_MODIFIABLE         FS_FL_USER_MODIFIABLE   /* User modifiable flags */

/*
 * ioctl commands
 */
#define EXT2_IOC_GETFLAGS               FS_IOC_GETFLAGS
#define EXT2_IOC_SETFLAGS               FS_IOC_SETFLAGS
#define EXT2_IOC_GETVERSION             FS_IOC_GETVERSION
#define EXT2_IOC_SETVERSION             FS_IOC_SETVERSION

/*
 * ioctl commands in 32 bit emulation
 */
#define EXT2_IOC32_GETFLAGS             FS_IOC32_GETFLAGS
#define EXT2_IOC32_SETFLAGS             FS_IOC32_SETFLAGS
#define EXT2_IOC32_GETVERSION           FS_IOC32_GETVERSION
#define EXT2_IOC32_SETVERSION           FS_IOC32_SETVERSION

/*
 * Structure of an inode on the disk
 */
struct ext2_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_reserved1;
                } linux1;
                struct {
                        __le32  h_i_translator;
                } hurd1;
                struct {
                        __le32  m_i_reserved1;
                } masix1;
        } osd1;                         /* OS dependent 1 */
        __le32  i_block[EXT2_N_BLOCKS];/* Pointers to blocks */
        __le32  i_generation;   /* File version (for NFS) */
        __le32  i_file_acl;     /* File ACL */
        __le32  i_dir_acl;      /* Directory ACL */
        __le32  i_faddr;        /* Fragment address */
        union {
                struct {
                        __u8    l_i_frag;       /* Fragment number */
                        __u8    l_i_fsize;      /* Fragment size */
                        __u16   i_pad1;
                        __le16  l_i_uid_high;   /* these 2 fields    */
                        __le16  l_i_gid_high;   /* were reserved2[0] */
                        __u32   l_i_reserved2;
                } linux2;
                struct {
                        __u8    h_i_frag;       /* Fragment number */
                        __u8    h_i_fsize;      /* Fragment size */
                        __le16  h_i_mode_high;
                        __le16  h_i_uid_high;
                        __le16  h_i_gid_high;
                        __le32  h_i_author;
                } hurd2;
                struct {
                        __u8    m_i_frag;       /* Fragment number */
                        __u8    m_i_fsize;      /* Fragment size */
                        __u16   m_pad1;
                        __u32   m_i_reserved2[2];
                } masix2;
        } osd2;                         /* OS dependent 2 */
};

#define i_size_high     i_dir_acl

#if defined(__KERNEL__) || defined(__linux__)
#define i_reserved1     osd1.linux1.l_i_reserved1
#define i_frag          osd2.linux2.l_i_frag
#define i_fsize         osd2.linux2.l_i_fsize
#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

#ifdef  __hurd__
#define i_translator    osd1.hurd1.h_i_translator
#define i_frag          osd2.hurd2.h_i_frag;
#define i_fsize         osd2.hurd2.h_i_fsize;
#define i_uid_high      osd2.hurd2.h_i_uid_high
#define i_gid_high      osd2.hurd2.h_i_gid_high
#define i_author        osd2.hurd2.h_i_author
#endif

#ifdef  __masix__
#define i_reserved1     osd1.masix1.m_i_reserved1
#define i_frag          osd2.masix2.m_i_frag
#define i_fsize         osd2.masix2.m_i_fsize
#define i_reserved2     osd2.masix2.m_i_reserved2
#endif

/*
 * File system states
 */
#define EXT2_VALID_FS                   0x0001  /* Unmounted cleanly */
#define EXT2_ERROR_FS                   0x0002  /* Errors detected */

/*
 * Mount flags
 */
#define EXT2_MOUNT_CHECK                0x000001  /* Do mount-time checks */
#define EXT2_MOUNT_OLDALLOC             0x000002  /* Don't use the new Orlov allocator */
#define EXT2_MOUNT_GRPID                0x000004  /* Create files with directory's group */
#define EXT2_MOUNT_DEBUG                0x000008  /* Some debugging messages */
#define EXT2_MOUNT_ERRORS_CONT          0x000010  /* Continue on errors */
#define EXT2_MOUNT_ERRORS_RO            0x000020  /* Remount fs ro on errors */
#define EXT2_MOUNT_ERRORS_PANIC         0x000040  /* Panic on errors */
#define EXT2_MOUNT_MINIX_DF             0x000080  /* Mimics the Minix statfs */
#define EXT2_MOUNT_NOBH                 0x000100  /* No buffer_heads */
#define EXT2_MOUNT_NO_UID32             0x000200  /* Disable 32-bit UIDs */
#define EXT2_MOUNT_XATTR_USER           0x004000  /* Extended user attributes */
#define EXT2_MOUNT_POSIX_ACL            0x008000  /* POSIX Access Control Lists */
#define EXT2_MOUNT_XIP                  0x010000  /* Execute in place */
#define EXT2_MOUNT_USRQUOTA             0x020000 /* user quota */
#define EXT2_MOUNT_GRPQUOTA             0x040000 /* group quota */


#define clear_opt(o, opt)               o &= ~EXT2_MOUNT_##opt
#define set_opt(o, opt)                 o |= EXT2_MOUNT_##opt
#define test_opt(sb, opt)               (EXT2_SB(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 {
        __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 */
        __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_log_frag_size;        /* Fragment size */
        __le32  s_blocks_per_group;     /* # Blocks per group */
        __le32  s_frags_per_group;      /* # Fragments per group */
        __le32  s_inodes_per_group;     /* # Inodes per group */
        __le32  s_mtime;                /* Mount time */
        __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 */
        __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 */
        __le16  s_def_resuid;           /* Default uid for reserved blocks */
        __le16  s_def_resgid;           /* Default gid for reserved blocks */
        /*
         * These fields are for EXT2_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 */
        __le32  s_feature_incompat;     /* incompatible feature set */
        __le32  s_feature_ro_compat;    /* readonly-compatible feature set */
        __u8    s_uuid[16];             /* 128-bit uuid for volume */
        char    s_volume_name[16];      /* volume name */
        char    s_last_mounted[64];     /* directory where last mounted */
        __le32  s_algorithm_usage_bitmap; /* For compression */
        /*
         * Performance hints.  Directory preallocation should only
         * happen if the EXT2_COMPAT_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 */
        __u16   s_padding1;
        /*
         * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.
         */
        __u8    s_journal_uuid[16];     /* uuid of journal superblock */
        __u32   s_journal_inum;         /* inode number of journal file */
        __u32   s_journal_dev;          /* device number of journal file */
        __u32   s_last_orphan;          /* start of list of inodes to delete */
        __u32   s_hash_seed[4];         /* HTREE hash seed */
        __u8    s_def_hash_version;     /* Default hash version to use */
        __u8    s_reserved_char_pad;
        __u16   s_reserved_word_pad;
        __le32  s_default_mount_opts;
        __le32  s_first_meta_bg;        /* First metablock block group */
        __u32   s_reserved[190];        /* Padding to the end of the block */
};

/*
 * Codes for operating systems
 */
#define EXT2_OS_LINUX           0
#define EXT2_OS_HURD            1
#define EXT2_OS_MASIX           2
#define EXT2_OS_FREEBSD         3
#define EXT2_OS_LITES           4

/*
 * Revision levels
 */
#define EXT2_GOOD_OLD_REV       0       /* The good old (original) format */
#define EXT2_DYNAMIC_REV        1       /* V2 format w/ dynamic inode sizes */

#define EXT2_CURRENT_REV        EXT2_GOOD_OLD_REV
#define EXT2_MAX_SUPP_REV       EXT2_DYNAMIC_REV

#define EXT2_GOOD_OLD_INODE_SIZE 128

/*
 * Feature set definitions
 */

#define EXT2_HAS_COMPAT_FEATURE(sb,mask)                        \
        ( EXT2_SB(sb)->s_es->s_feature_compat & cpu_to_le32(mask) )
#define EXT2_HAS_RO_COMPAT_FEATURE(sb,mask)                     \
        ( EXT2_SB(sb)->s_es->s_feature_ro_compat & cpu_to_le32(mask) )
#define EXT2_HAS_INCOMPAT_FEATURE(sb,mask)                      \
        ( EXT2_SB(sb)->s_es->s_feature_incompat & cpu_to_le32(mask) )
#define EXT2_SET_COMPAT_FEATURE(sb,mask)                        \
        EXT2_SB(sb)->s_es->s_feature_compat |= cpu_to_le32(mask)
#define EXT2_SET_RO_COMPAT_FEATURE(sb,mask)                     \
        EXT2_SB(sb)->s_es->s_feature_ro_compat |= cpu_to_le32(mask)
#define EXT2_SET_INCOMPAT_FEATURE(sb,mask)                      \
        EXT2_SB(sb)->s_es->s_feature_incompat |= cpu_to_le32(mask)
#define EXT2_CLEAR_COMPAT_FEATURE(sb,mask)                      \
        EXT2_SB(sb)->s_es->s_feature_compat &= ~cpu_to_le32(mask)
#define EXT2_CLEAR_RO_COMPAT_FEATURE(sb,mask)                   \
        EXT2_SB(sb)->s_es->s_feature_ro_compat &= ~cpu_to_le32(mask)
#define EXT2_CLEAR_INCOMPAT_FEATURE(sb,mask)                    \
        EXT2_SB(sb)->s_es->s_feature_incompat &= ~cpu_to_le32(mask)

#define EXT2_FEATURE_COMPAT_DIR_PREALLOC        0x0001
#define EXT2_FEATURE_COMPAT_IMAGIC_INODES       0x0002
#define EXT3_FEATURE_COMPAT_HAS_JOURNAL         0x0004
#define EXT2_FEATURE_COMPAT_EXT_ATTR            0x0008
#define EXT2_FEATURE_COMPAT_RESIZE_INO          0x0010
#define EXT2_FEATURE_COMPAT_DIR_INDEX           0x0020
#define EXT2_FEATURE_COMPAT_ANY                 0xffffffff

#define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER     0x0001
#define EXT2_FEATURE_RO_COMPAT_LARGE_FILE       0x0002
#define EXT2_FEATURE_RO_COMPAT_BTREE_DIR        0x0004
#define EXT2_FEATURE_RO_COMPAT_ANY              0xffffffff

#define EXT2_FEATURE_INCOMPAT_COMPRESSION       0x0001
#define EXT2_FEATURE_INCOMPAT_FILETYPE          0x0002
#define EXT3_FEATURE_INCOMPAT_RECOVER           0x0004
#define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV       0x0008
#define EXT2_FEATURE_INCOMPAT_META_BG           0x0010
#define EXT2_FEATURE_INCOMPAT_ANY               0xffffffff

#define EXT2_FEATURE_COMPAT_SUPP        EXT2_FEATURE_COMPAT_EXT_ATTR
#define EXT2_FEATURE_INCOMPAT_SUPP      (EXT2_FEATURE_INCOMPAT_FILETYPE| \
                                         EXT2_FEATURE_INCOMPAT_META_BG)
#define EXT2_FEATURE_RO_COMPAT_SUPP     (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
                                         EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
                                         EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
#define EXT2_FEATURE_RO_COMPAT_UNSUPPORTED      ~EXT2_FEATURE_RO_COMPAT_SUPP
#define EXT2_FEATURE_INCOMPAT_UNSUPPORTED       ~EXT2_FEATURE_INCOMPAT_SUPP

/*
 * Default values for user and/or group using reserved blocks
 */
#define EXT2_DEF_RESUID         0
#define EXT2_DEF_RESGID         0

/*
 * Default mount options
 */
#define EXT2_DEFM_DEBUG         0x0001
#define EXT2_DEFM_BSDGROUPS     0x0002
#define EXT2_DEFM_XATTR_USER    0x0004
#define EXT2_DEFM_ACL           0x0008
#define EXT2_DEFM_UID16         0x0010
    /* Not used by ext2, but reserved for use by ext3 */
#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 EXT2_NAME_LEN 255

struct ext2_dir_entry {
        __le32  inode;                  /* Inode number */
        __le16  rec_len;                /* Directory entry length */
        __le16  name_len;               /* Name length */
        char    name[EXT2_NAME_LEN];    /* File name */
};

/*
 * The new version of the directory entry.  Since EXT2 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 ext2_dir_entry_2 {
        __le32  inode;                  /* Inode number */
        __le16  rec_len;                /* Directory entry length */
        __u8    name_len;               /* Name length */
        __u8    file_type;
        char    name[EXT2_NAME_LEN];    /* File name */
};

/*
 * Ext2 directory file types.  Only the low 3 bits are used.  The
 * other bits are reserved for now.
 */
enum {
        EXT2_FT_UNKNOWN,
        EXT2_FT_REG_FILE,
        EXT2_FT_DIR,
        EXT2_FT_CHRDEV,
        EXT2_FT_BLKDEV,
        EXT2_FT_FIFO,
        EXT2_FT_SOCK,
        EXT2_FT_SYMLINK,
        EXT2_FT_MAX
};

/*
 * 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)

#endif  /* _LINUX_EXT2_FS_H */

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