/src/e2fsprogs/lib/ext2fs/ext2_fs.h

Source
/*
 *  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 <ext2fs/ext2_types.h>    /* Changed from linux/types.h */

#ifndef __GNUC_PREREQ
#if defined(__GNUC__) && defined(__GNUC_MINOR__)
#define __GNUC_PREREQ(maj, min) \
  ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
#else
#define __GNUC_PREREQ(maj, min) 0
#endif
#endif

#ifndef __nonstring
#ifdef __has_attribute
#if __has_attribute(__nonstring__)
#define __nonstring                    __attribute__((__nonstring__))
#else
#define __nonstring
#endif /* __has_attribute(__nonstring__) */
#else
# define __nonstring
#endif /* __has_attribute */
#endif /* __nonstring */

/*
 * 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"

/*
 * Special inode numbers
 */
#define EXT2_BAD_INO     1  /* Bad blocks inode */
#define EXT2_ROOT_INO    2  /* Root inode */
#define EXT4_USR_QUOTA_INO   3  /* User quota inode */
#define EXT4_GRP_QUOTA_INO   4  /* Group quota inode */
#define EXT2_BOOT_LOADER_INO   5  /* Boot loader inode */
#define EXT2_UNDEL_DIR_INO   6  /* Undelete directory inode */
#define EXT2_RESIZE_INO    7  /* Reserved group descriptors inode */
#define EXT2_JOURNAL_INO   8  /* Journal inode */
#define EXT2_EXCLUDE_INO   9  /* The "exclude" inode, for snapshots */
#define EXT4_REPLICA_INO  10  /* Used by non-upstream feature */

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

/*
 * The second extended file system magic number
 */
#define EXT2_SUPER_MAGIC  0xEF53

#ifdef __KERNEL__
#define EXT2_SB(sb) (&((sb)->u.ext2_sb))
#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   65000

/*
 * Macro-instructions used to manage several block sizes
 */
#define EXT2_MIN_BLOCK_LOG_SIZE   10  /* 1024 */
#define EXT2_MAX_BLOCK_LOG_SIZE   16  /* 65536 */
#define EXT2_MIN_BLOCK_SIZE (1 << EXT2_MIN_BLOCK_LOG_SIZE)
#define EXT2_MAX_BLOCK_SIZE (1 << EXT2_MAX_BLOCK_LOG_SIZE)
#ifdef __KERNEL__
#define EXT2_BLOCK_SIZE(s)  ((s)->s_blocksize)
#define EXT2_BLOCK_SIZE_BITS(s) ((s)->s_blocksize_bits)
#define EXT2_ADDR_PER_BLOCK_BITS(s) (EXT2_SB(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_BLOCK_SIZE(s)  (EXT2_MIN_BLOCK_SIZE << (s)->s_log_block_size)
#define EXT2_BLOCK_SIZE_BITS(s) ((s)->s_log_block_size + 10)
#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
#define EXT2_ADDR_PER_BLOCK(s)  (EXT2_BLOCK_SIZE(s) / sizeof(__u32))

/*
 * Macro-instructions used to manage allocation clusters
 */
#define EXT2_MIN_CLUSTER_LOG_SIZE EXT2_MIN_BLOCK_LOG_SIZE
#define EXT2_MAX_CLUSTER_LOG_SIZE 29  /* 512MB  */
#define EXT2_MIN_CLUSTER_SIZE   EXT2_MIN_BLOCK_SIZE
#define EXT2_MAX_CLUSTER_SIZE   (1 << EXT2_MAX_CLUSTER_LOG_SIZE)
#define EXT2_CLUSTER_SIZE(s)    (EXT2_MIN_BLOCK_SIZE << \
            (s)->s_log_cluster_size)
#define EXT2_CLUSTER_SIZE_BITS(s) ((s)->s_log_cluster_size + 10)

/*
 * Macro-instructions used to manage fragments
 *
 * Note: for backwards compatibility only, for the dump program.
 * Ext2/3/4 will never support fragments....
 */
#define EXT2_MIN_FRAG_SIZE              EXT2_MIN_BLOCK_SIZE
#define EXT2_MAX_FRAG_SIZE              EXT2_MAX_BLOCK_SIZE
#define EXT2_MIN_FRAG_LOG_SIZE          EXT2_MIN_BLOCK_LOG_SIZE
#define EXT2_FRAG_SIZE(s)   EXT2_BLOCK_SIZE(s)
#define EXT2_FRAGS_PER_BLOCK(s)   1

/*
 * ACL structures
 */
struct ext2_acl_header  /* Header of Access Control Lists */
{
  __u32 aclh_size;
  __u32 aclh_file_count;
  __u32 aclh_acle_count;
  __u32 aclh_first_acle;
};

struct ext2_acl_entry /* Access Control List Entry */
{
  __u32 acle_size;
  __u16 acle_perms; /* Access permissions */
  __u16 acle_type;  /* Type of entry */
  __u16 acle_tag; /* User or group identity */
  __u16 acle_pad1;
  __u32 acle_next;  /* Pointer on next entry for the */
          /* same inode or on next free entry */
};

/*
 * Structure of a blocks group descriptor
 */
struct ext2_group_desc
{
  __u32 bg_block_bitmap;  /* Blocks bitmap block */
  __u32 bg_inode_bitmap;  /* Inodes bitmap block */
  __u32 bg_inode_table;   /* Inodes table block */
  __u16 bg_free_blocks_count; /* Free blocks count */
  __u16 bg_free_inodes_count; /* Free inodes count */
  __u16 bg_used_dirs_count; /* Directories count */
  __u16 bg_flags;
  __u32 bg_exclude_bitmap_lo; /* Exclude bitmap for snapshots */
  __u16 bg_block_bitmap_csum_lo;/* crc32c(s_uuid+grp_num+bitmap) LSB */
  __u16 bg_inode_bitmap_csum_lo;/* crc32c(s_uuid+grp_num+bitmap) LSB */
  __u16 bg_itable_unused; /* Unused inodes count */
  __u16 bg_checksum;    /* crc16(s_uuid+group_num+group_desc)*/
};

/*
 * Structure of a blocks group descriptor
 */
struct ext4_group_desc
{
  __u32 bg_block_bitmap;  /* Blocks bitmap block */
  __u32 bg_inode_bitmap;  /* Inodes bitmap block */
  __u32 bg_inode_table;   /* Inodes table block */
  __u16 bg_free_blocks_count; /* Free blocks count */
  __u16 bg_free_inodes_count; /* Free inodes count */
  __u16 bg_used_dirs_count; /* Directories count */
  __u16 bg_flags;   /* EXT4_BG_flags (INODE_UNINIT, etc) */
  __u32 bg_exclude_bitmap_lo; /* Exclude bitmap for snapshots */
  __u16 bg_block_bitmap_csum_lo;/* crc32c(s_uuid+grp_num+bitmap) LSB */
  __u16 bg_inode_bitmap_csum_lo;/* crc32c(s_uuid+grp_num+bitmap) LSB */
  __u16 bg_itable_unused; /* Unused inodes count */
  __u16 bg_checksum;    /* crc16(sb_uuid+group+desc) */
  __u32 bg_block_bitmap_hi; /* Blocks bitmap block MSB */
  __u32 bg_inode_bitmap_hi; /* Inodes bitmap block MSB */
  __u32 bg_inode_table_hi;  /* Inodes table block MSB */
  __u16 bg_free_blocks_count_hi;/* Free blocks count MSB */
  __u16 bg_free_inodes_count_hi;/* Free inodes count MSB */
  __u16 bg_used_dirs_count_hi;  /* Directories count MSB */
  __u16 bg_itable_unused_hi;  /* Unused inodes count MSB */
  __u32 bg_exclude_bitmap_hi; /* Exclude bitmap block MSB */
  __u16 bg_block_bitmap_csum_hi;/* crc32c(s_uuid+grp_num+bitmap) MSB */
  __u16 bg_inode_bitmap_csum_hi;/* crc32c(s_uuid+grp_num+bitmap) MSB */
  __u32 bg_reserved;
};

#define EXT4_BG_INODE_BITMAP_CSUM_HI_END  \
  (offsetof(struct ext4_group_desc, bg_inode_bitmap_csum_hi) + \
   sizeof(__u16))
#define EXT4_BG_BLOCK_BITMAP_CSUM_HI_LOCATION \
  (offsetof(struct ext4_group_desc, bg_block_bitmap_csum_hi) + \
   sizeof(__u16))

#define EXT2_BG_INODE_UNINIT  0x0001 /* Inode table/bitmap not initialized */
#define EXT2_BG_BLOCK_UNINIT  0x0002 /* Block bitmap not initialized */
#define EXT2_BG_INODE_ZEROED  0x0004 /* On-disk itable initialized to zero */

/*
 * Data structures used by the directory indexing feature
 *
 * Note: all of the multibyte integer fields are little endian.
 */

/*
 * Note: dx_root_info is laid out so that if it should somehow get
 * overlaid by a dirent the two low bits of the hash version will be
 * zero.  Therefore, the hash version mod 4 should never be 0.
 * Sincerely, the paranoia department.
 */
struct ext2_dx_root_info {
  __u32 reserved_zero;
  __u8 hash_version; /* 0 now, 1 at release */
  __u8 info_length; /* 8 */
  __u8 indirect_levels;
  __u8 unused_flags;
};

#define EXT2_HASH_LEGACY    0
#define EXT2_HASH_HALF_MD4    1
#define EXT2_HASH_TEA     2
#define EXT2_HASH_LEGACY_UNSIGNED 3 /* reserved for userspace lib */
#define EXT2_HASH_HALF_MD4_UNSIGNED 4 /* reserved for userspace lib */
#define EXT2_HASH_TEA_UNSIGNED    5 /* reserved for userspace lib */
#define EXT2_HASH_SIPHASH   6

#define EXT2_HASH_FLAG_INCOMPAT 0x1

#define EXT4_DX_BLOCK_MASK 0x0fffffff

struct ext2_dx_entry {
  __le32 hash;
  __le32 block;
};

struct ext2_dx_countlimit {
  __le16 limit;
  __le16 count;
};

/*
 * This goes at the end of each htree block.
 */
struct ext2_dx_tail {
  __le32 dt_reserved;
  __le32 dt_checksum; /* crc32c(uuid+inum+dxblock) */
};

/*
 * Macro-instructions used to manage group descriptors
 */
#define EXT2_MIN_DESC_SIZE             32
#define EXT2_MIN_DESC_SIZE_64BIT       64
#define EXT2_MAX_DESC_SIZE             EXT2_MIN_BLOCK_SIZE
#define EXT2_DESC_SIZE(s)                                                \
  (ext2fs_has_feature_64bit(s) ? (s)->s_desc_size : EXT2_MIN_DESC_SIZE)

#define EXT2_BLOCKS_PER_GROUP(s)  (EXT2_SB(s)->s_blocks_per_group)
#define EXT2_INODES_PER_GROUP(s)  (EXT2_SB(s)->s_inodes_per_group)
#define EXT2_CLUSTERS_PER_GROUP(s)  (EXT2_SB(s)->s_clusters_per_group)
#define EXT2_INODES_PER_BLOCK(s)  (EXT2_BLOCK_SIZE(s)/EXT2_INODE_SIZE(s))
/* limits imposed by 16-bit value gd_free_{blocks,inode}_count */
#define EXT2_MAX_BLOCKS_PER_GROUP(s)  ((((unsigned) 1 << 16) - 8) * \
           (EXT2_CLUSTER_SIZE(s) / \
            EXT2_BLOCK_SIZE(s)))
#define EXT2_MAX_CLUSTERS_PER_GROUP(s)  (((unsigned) 1 << 16) - 8)
#define EXT2_MAX_INODES_PER_GROUP(s)  (((unsigned) 1 << 16) - \
           EXT2_INODES_PER_BLOCK(s))
#ifdef __KERNEL__
#define EXT2_DESC_PER_BLOCK(s)    (EXT2_SB(s)->s_desc_per_block)
#define EXT2_DESC_PER_BLOCK_BITS(s) (EXT2_SB(s)->s_desc_per_block_bits)
#else
#define EXT2_DESC_PER_BLOCK(s)    (EXT2_BLOCK_SIZE(s) / EXT2_DESC_SIZE(s))
#endif

#define EXT2_GROUPS_TO_BLOCKS(s, g)   ((blk64_t) EXT2_BLOCKS_PER_GROUP(s) * \
               (g))
#define EXT2_GROUPS_TO_CLUSTERS(s, g) ((blk64_t) EXT2_CLUSTERS_PER_GROUP(s) * \
               (g))

/*
 * 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     0x00000001 /* Secure deletion */
#define EXT2_UNRM_FL      0x00000002 /* Undelete */
#define EXT2_COMPR_FL     0x00000004 /* Compress file */
#define EXT2_SYNC_FL      0x00000008 /* Synchronous updates */
#define EXT2_IMMUTABLE_FL   0x00000010 /* Immutable file */
#define EXT2_APPEND_FL      0x00000020 /* writes to file may only append */
#define EXT2_NODUMP_FL      0x00000040 /* do not dump file */
#define EXT2_NOATIME_FL     0x00000080 /* do not update atime */
/* Reserved for compression usage... */
#define EXT2_DIRTY_FL     0x00000100
#define EXT2_COMPRBLK_FL    0x00000200 /* One or more compressed clusters */
#define EXT2_NOCOMPR_FL     0x00000400 /* Access raw compressed data */
  /* nb: was previously EXT2_ECOMPR_FL */
#define EXT4_ENCRYPT_FL     0x00000800 /* encrypted inode */
/* End compression flags --- maybe not all used */
#define EXT2_BTREE_FL     0x00001000 /* btree format dir */
#define EXT2_INDEX_FL     0x00001000 /* hash-indexed directory */
#define EXT2_IMAGIC_FL      0x00002000
#define EXT3_JOURNAL_DATA_FL    0x00004000 /* file data should be journaled */
#define EXT2_NOTAIL_FL      0x00008000 /* file tail should not be merged */
#define EXT2_DIRSYNC_FL     0x00010000 /* Synchronous directory modifications */
#define EXT2_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_VERITY_FL      0x00100000 /* Verity protected inode */
#define EXT4_EA_INODE_FL          0x00200000 /* Inode used for large EA */
/* EXT4_EOFBLOCKS_FL 0x00400000 was here */
#define FS_NOCOW_FL     0x00800000 /* Do not cow file */
#define EXT4_SNAPFILE_FL    0x01000000  /* Inode is a snapshot */
#define FS_DAX_FL     0x02000000 /* Inode is DAX */
#define EXT4_SNAPFILE_DELETED_FL  0x04000000  /* Snapshot is being deleted */
#define EXT4_SNAPFILE_SHRUNK_FL   0x08000000  /* Snapshot shrink has completed */
#define EXT4_INLINE_DATA_FL   0x10000000 /* Inode has inline data */
#define EXT4_PROJINHERIT_FL   0x20000000 /* Create with parents projid */
#define EXT4_CASEFOLD_FL    0x40000000 /* Casefolded file */
#define EXT2_RESERVED_FL    0x80000000 /* reserved for ext2 lib */

#define EXT2_FL_USER_VISIBLE    0x604BDFFF /* User visible flags */
#define EXT2_FL_USER_MODIFIABLE   0x604B80FF /* User modifiable flags */

/*
 * ioctl commands
 */

/* Used for online resize */
struct ext2_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;   /* Number of reserved GDT blocks in group */
};

struct ext4_new_group_input {
  __u32 group;    /* Group number for this data */
  __u64 block_bitmap; /* Absolute block number of block bitmap */
  __u64 inode_bitmap; /* Absolute block number of inode bitmap */
  __u64 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;
};

#ifdef __GNU__      /* Needed for the Hurd */
#define _IOT_ext2_new_group_input _IOT (_IOTS(__u32), 5, _IOTS(__u16), 2, 0, 0)
#endif

#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)
#define EXT2_IOC_GETVERSION_NEW   _IOR('f', 3, long)
#define EXT2_IOC_SETVERSION_NEW   _IOW('f', 4, long)
#define EXT2_IOC_GROUP_EXTEND   _IOW('f', 7, unsigned long)
#define EXT2_IOC_GROUP_ADD    _IOW('f', 8,struct ext2_new_group_input)
#define EXT4_IOC_GROUP_ADD    _IOW('f', 8,struct ext4_new_group_input)
#define EXT4_IOC_RESIZE_FS    _IOW('f', 16, __u64)

/*
 * Structure of an inode on the disk
 */
struct ext2_inode {
/*00*/  __u16 i_mode;   /* File mode */
  __u16 i_uid;    /* Low 16 bits of Owner Uid */
  __u32 i_size;   /* Size in bytes */
  __u32 i_atime;  /* Access time */
  __u32 i_ctime;  /* Inode change time */
/*10*/  __u32 i_mtime;  /* Modification time */
  __u32 i_dtime;  /* Deletion Time */
  __u16 i_gid;    /* Low 16 bits of Group Id */
  __u16 i_links_count;  /* Links count */
  __u32 i_blocks; /* Blocks count */
/*20*/  __u32 i_flags;  /* File flags */
  union {
    struct {
      __u32 l_i_version; /* was l_i_reserved1 */
    } linux1;
    struct {
      __u32  h_i_translator;
    } hurd1;
  } osd1;       /* OS dependent 1 */
/*28*/  __u32 i_block[EXT2_N_BLOCKS];/* Pointers to blocks */
/*64*/  __u32 i_generation; /* File version (for NFS) */
  __u32 i_file_acl; /* File ACL */
  __u32 i_size_high;
/*70*/  __u32 i_faddr;  /* Fragment address */
  union {
    struct {
      __u16 l_i_blocks_hi;
      __u16 l_i_file_acl_high;
      __u16 l_i_uid_high; /* these 2 fields    */
      __u16 l_i_gid_high; /* were reserved2[0] */
      __u16 l_i_checksum_lo; /* crc32c(uuid+inum+inode) */
      __u16 l_i_reserved;
    } linux2;
    struct {
      __u8  h_i_frag; /* Fragment number */
      __u8  h_i_fsize;  /* Fragment size */
      __u16 h_i_mode_high;
      __u16 h_i_uid_high;
      __u16 h_i_gid_high;
      __u32 h_i_author;
    } hurd2;
  } osd2;       /* OS dependent 2 */
};

/*
 * Permanent part of an large inode on the disk
 */
struct ext2_inode_large {
/*00*/  __u16 i_mode;   /* File mode */
  __u16 i_uid;    /* Low 16 bits of Owner Uid */
  __u32 i_size;   /* Size in bytes */
  __u32 i_atime;  /* Access time */
  __u32 i_ctime;  /* Inode Change time */
/*10*/  __u32 i_mtime;  /* Modification time */
  __u32 i_dtime;  /* Deletion Time */
  __u16 i_gid;    /* Low 16 bits of Group Id */
  __u16 i_links_count;  /* Links count */
  __u32 i_blocks; /* Blocks count */
/*20*/  __u32 i_flags;  /* File flags */
  union {
    struct {
      __u32 l_i_version; /* was l_i_reserved1 */
    } linux1;
    struct {
      __u32  h_i_translator;
    } hurd1;
  } osd1;       /* OS dependent 1 */
/*28*/  __u32 i_block[EXT2_N_BLOCKS];/* Pointers to blocks */
/*64*/  __u32 i_generation; /* File version (for NFS) */
  __u32 i_file_acl; /* File ACL */
  __u32 i_size_high;
/*70*/  __u32 i_faddr;  /* Fragment address */
  union {
    struct {
      __u16 l_i_blocks_hi;
      __u16 l_i_file_acl_high;
      __u16 l_i_uid_high; /* these 2 fields    */
      __u16 l_i_gid_high; /* were reserved2[0] */
      __u16 l_i_checksum_lo; /* crc32c(uuid+inum+inode) */
      __u16 l_i_reserved;
    } linux2;
    struct {
      __u8  h_i_frag; /* Fragment number */
      __u8  h_i_fsize;  /* Fragment size */
      __u16 h_i_mode_high;
      __u16 h_i_uid_high;
      __u16 h_i_gid_high;
      __u32 h_i_author;
    } hurd2;
  } osd2;       /* OS dependent 2 */
/*80*/  __u16 i_extra_isize;
  __u16 i_checksum_hi;  /* crc32c(uuid+inum+inode) */
  __u32 i_ctime_extra;  /* extra Change time (nsec << 2 | epoch) */
  __u32 i_mtime_extra;  /* extra Modification time (nsec << 2 | epoch) */
  __u32 i_atime_extra;  /* extra Access time (nsec << 2 | epoch) */
/*90*/  __u32 i_crtime; /* File creation time */
  __u32 i_crtime_extra; /* extra File creation time (nsec << 2 | epoch)*/
  __u32 i_version_hi; /* high 32 bits for 64-bit version */
/*9c*/  __u32   i_projid;       /* Project ID */
};

#define EXT4_INODE_CSUM_HI_EXTRA_END  \
  (offsetof(struct ext2_inode_large, i_checksum_hi) + sizeof(__u16) - \
   EXT2_GOOD_OLD_INODE_SIZE)

#define EXT4_EPOCH_BITS 2
#define EXT4_EPOCH_MASK ((1 << EXT4_EPOCH_BITS) - 1)

#define i_checksum_lo osd2.linux2.l_i_checksum_lo

#define ext2fs_inode_includes(size, field)        \
  ((size) >= (sizeof(((struct ext2_inode_large *)0)->field) + \
        offsetof(struct ext2_inode_large, field)))

#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
#else
#if defined(__GNU__)

#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  /* __GNU__ */
#endif  /* defined(__KERNEL__) || defined(__linux__) */

#define inode_uid(inode)  ((inode).i_uid | (unsigned)(inode).osd2.linux2.l_i_uid_high << 16)
#define inode_gid(inode)  ((inode).i_gid | (unsigned)(inode).osd2.linux2.l_i_gid_high << 16)
#define inode_projid(inode) ((inode).i_projid)
#define ext2fs_set_i_uid_high(inode,x) ((inode).osd2.linux2.l_i_uid_high = (x))
#define ext2fs_set_i_gid_high(inode,x) ((inode).osd2.linux2.l_i_gid_high = (x))

static inline
struct ext2_inode *EXT2_INODE(struct ext2_inode_large *large_inode)
{
  return (struct ext2_inode *) large_inode;
}

/*
 * File system states
 */
#define EXT2_VALID_FS     0x0001  /* Unmounted cleanly */
#define EXT2_ERROR_FS     0x0002  /* Errors detected */
#define EXT3_ORPHAN_FS      0x0004  /* Orphans being recovered */
#define EXT4_FC_REPLAY      0x0020  /* Ext4 fast commit replay ongoing */

/*
 * Misc. filesystem flags
 */
#define EXT2_FLAGS_SIGNED_HASH    0x0001  /* Signed dirhash in use */
#define EXT2_FLAGS_UNSIGNED_HASH  0x0002  /* Unsigned dirhash in use */
#define EXT2_FLAGS_TEST_FILESYS   0x0004  /* OK for use on development code */
#define EXT2_FLAGS_IS_SNAPSHOT    0x0010  /* This is a snapshot image */
#define EXT2_FLAGS_FIX_SNAPSHOT   0x0020  /* Snapshot inodes corrupted */
#define EXT2_FLAGS_FIX_EXCLUDE    0x0040  /* Exclude bitmaps corrupted */

/*
 * Mount flags
 */
#define EXT2_MOUNT_CHECK    0x0001  /* Do mount-time checks */
#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 EXT2_MOUNT_MINIX_DF   0x0080  /* Mimics the Minix statfs */
#define EXT2_MOUNT_NO_UID32   0x0200  /* Disable 32-bit UIDs */

#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

#if (__GNUC__ >= 4)
#define ext4_offsetof(TYPE,MEMBER) __builtin_offsetof(TYPE,MEMBER)
#else
#define ext4_offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
#endif

/* Metadata checksum algorithms */
#define EXT2_CRC32C_CHKSUM    1

/* Encryption algorithms, key size and key reference len */
#define EXT4_ENCRYPTION_MODE_INVALID    0
#define EXT4_ENCRYPTION_MODE_AES_256_XTS  1
#define EXT4_ENCRYPTION_MODE_AES_256_GCM  2
#define EXT4_ENCRYPTION_MODE_AES_256_CBC  3
#define EXT4_ENCRYPTION_MODE_AES_256_CTS  4

#define EXT4_AES_256_XTS_KEY_SIZE   64
#define EXT4_AES_256_GCM_KEY_SIZE   32
#define EXT4_AES_256_CBC_KEY_SIZE   32
#define EXT4_AES_256_CTS_KEY_SIZE   32
#define EXT4_MAX_KEY_SIZE     64

#define EXT4_KEY_DESCRIPTOR_SIZE    8
#define EXT4_CRYPTO_BLOCK_SIZE      16

/* Password derivation constants */
#define EXT4_MAX_PASSPHRASE_SIZE    1024
#define EXT4_MAX_SALT_SIZE      256
#define EXT4_PBKDF2_ITERATIONS      0xFFFF

#define EXT2_LABEL_LEN        16

/*
 * Policy provided via an ioctl on the topmost directory. This
 * structure is also in the kernel.
 */
struct ext4_encryption_policy {
  char version;
  char contents_encryption_mode;
  char filenames_encryption_mode;
  char flags;
  char master_key_descriptor[EXT4_KEY_DESCRIPTOR_SIZE];
} __attribute__((__packed__));

struct ext4_encryption_key {
        __u32 mode;
        char raw[EXT4_MAX_KEY_SIZE];
        __u32 size;
} __attribute__((__packed__));

/*
 * Structure of the super block
 */
struct ext2_super_block {
/*000*/ __u32 s_inodes_count;   /* Inodes count */
  __u32 s_blocks_count;   /* Blocks count */
  __u32 s_r_blocks_count; /* Reserved blocks count */
  __u32 s_free_blocks_count;  /* Free blocks count */
/*010*/ __u32 s_free_inodes_count;  /* Free inodes count */
  __u32 s_first_data_block; /* First Data Block */
  __u32 s_log_block_size; /* Block size */
  __u32 s_log_cluster_size; /* Allocation cluster size */
/*020*/ __u32 s_blocks_per_group; /* # Blocks per group */
  __u32 s_clusters_per_group; /* # Fragments per group */
  __u32 s_inodes_per_group; /* # Inodes per group */
  __u32 s_mtime;    /* Mount time */
/*030*/ __u32 s_wtime;    /* Write time */
  __u16 s_mnt_count;    /* Mount count */
  __s16 s_max_mnt_count;  /* Maximal mount count */
  __u16 s_magic;    /* Magic signature */
  __u16 s_state;    /* File system state */
  __u16 s_errors;   /* Behaviour when detecting errors */
  __u16 s_minor_rev_level;  /* minor revision level */
/*040*/ __u32 s_lastcheck;    /* time of last check */
  __u32 s_checkinterval;  /* max. time between checks */
  __u32 s_creator_os;   /* OS */
  __u32 s_rev_level;    /* Revision level */
/*050*/ __u16 s_def_resuid;   /* Default uid for reserved blocks */
  __u16 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...
   */
  __u32 s_first_ino;    /* First non-reserved inode */
  __u16   s_inode_size;   /* size of inode structure */
  __u16 s_block_group_nr; /* block group # of this superblock */
  __u32 s_feature_compat; /* compatible feature set */
/*060*/ __u32 s_feature_incompat; /* incompatible feature set */
  __u32 s_feature_ro_compat;  /* readonly-compatible feature set */
/*068*/ __u8  s_uuid[16] __nonstring;   /* 128-bit uuid for volume */
/*078*/ __u8  s_volume_name[EXT2_LABEL_LEN] __nonstring;  /* volume name, no NUL? */
/*088*/ __u8  s_last_mounted[64] __nonstring; /* directory last mounted on, no NUL? */
/*0c8*/ __u32 s_algorithm_usage_bitmap; /* For compression */
  /*
   * Performance hints.  Directory preallocation should only
   * happen if the EXT2_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 */
  __u16 s_reserved_gdt_blocks;  /* Per group table for online growth */
  /*
   * Journaling support valid if EXT2_FEATURE_COMPAT_HAS_JOURNAL set.
   */
/*0d0*/ __u8  s_journal_uuid[16] __nonstring; /* uuid of journal superblock */
/*0e0*/ __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 */
/*0ec*/ __u32 s_hash_seed[4];   /* HTREE hash seed */
/*0fc*/ __u8  s_def_hash_version; /* Default hash version to use */
  __u8  s_jnl_backup_type;  /* Default type of journal backup */
  __u16 s_desc_size;    /* Group desc. size: INCOMPAT_64BIT */
/*100*/ __u32 s_default_mount_opts; /* default EXT2_MOUNT_* flags used */
  __u32 s_first_meta_bg;  /* First metablock group */
  __u32 s_mkfs_time;    /* When the filesystem was created */
/*10c*/ __u32 s_jnl_blocks[17]; /* Backup of the journal inode */
/*150*/ __u32 s_blocks_count_hi;  /* Blocks count high 32bits */
  __u32 s_r_blocks_count_hi;  /* Reserved blocks count high 32 bits*/
  __u32 s_free_blocks_hi; /* Free blocks count */
  __u16 s_min_extra_isize;  /* All inodes have at least # bytes */
  __u16 s_want_extra_isize; /* New inodes should reserve # bytes */
/*160*/ __u32 s_flags;    /* Miscellaneous flags */
  __u16 s_raid_stride;    /* RAID stride in blocks */
  __u16 s_mmp_update_interval;  /* # seconds to wait in MMP checking */
  __u64 s_mmp_block;    /* Block for multi-mount protection */
/*170*/ __u32 s_raid_stripe_width;  /* blocks on all data disks (N*stride)*/
  __u8  s_log_groups_per_flex;  /* FLEX_BG group size */
  __u8  s_checksum_type;  /* metadata checksum algorithm */
  __u8  s_encryption_level; /* versioning level for encryption */
  __u8  s_reserved_pad;   /* Padding to next 32bits */
  __u64 s_kbytes_written; /* nr of lifetime kilobytes written */
/*180*/ __u32 s_snapshot_inum;  /* Inode number of active snapshot */
  __u32 s_snapshot_id;    /* sequential ID of active snapshot */
  __u64 s_snapshot_r_blocks_count; /* active snapshot reserved blocks */
/*190*/ __u32 s_snapshot_list;  /* inode number of disk snapshot list */
#define EXT4_S_ERR_START ext4_offsetof(struct ext2_super_block, s_error_count)
  __u32 s_error_count;    /* number of fs errors */
  __u32 s_first_error_time; /* first time an error happened */
  __u32 s_first_error_ino;  /* inode involved in first error */
/*1a0*/ __u64 s_first_error_block;  /* block involved in first error */
  __u8  s_first_error_func[32] __nonstring; /* function where error hit, no NUL? */
/*1c8*/ __u32 s_first_error_line; /* line number where error happened */
  __u32 s_last_error_time;  /* most recent time of an error */
/*1d0*/ __u32 s_last_error_ino; /* inode involved in last error */
  __u32 s_last_error_line;  /* line number where error happened */
  __u64 s_last_error_block; /* block involved of last error */
/*1e0*/ __u8  s_last_error_func[32] __nonstring;  /* function where error hit, no NUL? */
#define EXT4_S_ERR_END ext4_offsetof(struct ext2_super_block, s_mount_opts)
/*200*/ __u8  s_mount_opts[64] __nonstring; /* default mount options, no NUL? */
/*240*/ __u32 s_usr_quota_inum; /* inode number of user quota file */
  __u32 s_grp_quota_inum; /* inode number of group quota file */
  __u32 s_overhead_clusters;  /* overhead blocks/clusters in fs */
/*24c*/ __u32 s_backup_bgs[2];  /* If sparse_super2 enabled */
/*254*/ __u8  s_encrypt_algos[4]; /* Encryption algorithms in use  */
/*258*/ __u8  s_encrypt_pw_salt[16];  /* Salt used for string2key algorithm */
/*268*/ __le32  s_lpf_ino;    /* Location of the lost+found inode */
  __le32  s_prj_quota_inum; /* inode for tracking project quota */
/*270*/ __le32  s_checksum_seed;  /* crc32c(orig_uuid) if csum_seed set */
/*274*/ __u8  s_wtime_hi;
  __u8  s_mtime_hi;
  __u8  s_mkfs_time_hi;
  __u8  s_lastcheck_hi;
  __u8  s_first_error_time_hi;
  __u8  s_last_error_time_hi;
  __u8  s_first_error_errcode;
  __u8    s_last_error_errcode;
/*27c*/ __le16  s_encoding;   /* Filename charset encoding */
  __le16  s_encoding_flags; /* Filename charset encoding flags */
  __le32  s_orphan_file_inum; /* Inode for tracking orphan inodes */
  __le32  s_reserved[94];   /* Padding to the end of the block */
/*3fc*/ __u32 s_checksum;   /* crc32c(superblock) */
};

#define EXT4_S_ERR_LEN (EXT4_S_ERR_END - EXT4_S_ERR_START)
#define EXT2_LEN_STR(buf) (int)sizeof(buf), (char *)buf

/*
 * Codes for operating systems
 */
#define EXT2_OS_LINUX   0
#define EXT2_OS_HURD    1
#define EXT2_OBSO_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

#define EXT4_EXTRA_TIMESTAMP_MAX  (((int64_t)1 << 34) - 1  + INT32_MIN)
#define EXT4_NON_EXTRA_TIMESTAMP_MAX  INT32_MAX
#define EXT4_TIMESTAMP_MIN    INT32_MIN

/*
 * Journal inode backup types
 */
#define EXT3_JNL_BACKUP_BLOCKS  1

/*
 * Feature set definitions
 */

#define EXT2_HAS_COMPAT_FEATURE(sb,mask)      \
  ( EXT2_SB(sb)->s_feature_compat & (mask) )
#define EXT2_HAS_RO_COMPAT_FEATURE(sb,mask)     \
  ( EXT2_SB(sb)->s_feature_ro_compat & (mask) )
#define EXT2_HAS_INCOMPAT_FEATURE(sb,mask)      \
  ( EXT2_SB(sb)->s_feature_incompat & (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_INODE  0x0010
#define EXT2_FEATURE_COMPAT_DIR_INDEX   0x0020
#define EXT2_FEATURE_COMPAT_LAZY_BG   0x0040
/* #define EXT2_FEATURE_COMPAT_EXCLUDE_INODE  0x0080 not used, legacy */
#define EXT2_FEATURE_COMPAT_EXCLUDE_BITMAP  0x0100
#define EXT4_FEATURE_COMPAT_SPARSE_SUPER2 0x0200
#define EXT4_FEATURE_COMPAT_FAST_COMMIT   0x0400
#define EXT4_FEATURE_COMPAT_STABLE_INODES 0x0800
#define EXT4_FEATURE_COMPAT_ORPHAN_FILE   0x1000

#define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001
#define EXT2_FEATURE_RO_COMPAT_LARGE_FILE 0x0002
/* #define EXT2_FEATURE_RO_COMPAT_BTREE_DIR 0x0004 not used */
#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_RO_COMPAT_HAS_SNAPSHOT 0x0080
#define EXT4_FEATURE_RO_COMPAT_QUOTA    0x0100
#define EXT4_FEATURE_RO_COMPAT_BIGALLOC   0x0200
/*
 * METADATA_CSUM implies GDT_CSUM.  When METADATA_CSUM is set, group
 * descriptor checksums use the same algorithm as all other data
 * structures' checksums.
 */
#define EXT4_FEATURE_RO_COMPAT_METADATA_CSUM  0x0400
#define EXT4_FEATURE_RO_COMPAT_REPLICA    0x0800
#define EXT4_FEATURE_RO_COMPAT_READONLY   0x1000
#define EXT4_FEATURE_RO_COMPAT_PROJECT    0x2000 /* Project quota */
#define EXT4_FEATURE_RO_COMPAT_SHARED_BLOCKS  0x4000
#define EXT4_FEATURE_RO_COMPAT_VERITY   0x8000
#define EXT4_FEATURE_RO_COMPAT_ORPHAN_PRESENT 0x10000

#define EXT2_FEATURE_INCOMPAT_COMPRESSION 0x0001
#define EXT2_FEATURE_INCOMPAT_FILETYPE    0x0002
#define EXT3_FEATURE_INCOMPAT_RECOVER   0x0004 /* Needs recovery */
#define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV 0x0008 /* Journal device */
#define EXT2_FEATURE_INCOMPAT_META_BG   0x0010
#define EXT3_FEATURE_INCOMPAT_EXTENTS   0x0040
#define EXT4_FEATURE_INCOMPAT_64BIT   0x0080
#define EXT4_FEATURE_INCOMPAT_MMP   0x0100
#define EXT4_FEATURE_INCOMPAT_FLEX_BG   0x0200
#define EXT4_FEATURE_INCOMPAT_EA_INODE    0x0400
#define EXT4_FEATURE_INCOMPAT_DIRDATA   0x1000
#define EXT4_FEATURE_INCOMPAT_CSUM_SEED   0x2000
#define EXT4_FEATURE_INCOMPAT_LARGEDIR    0x4000 /* >2GB or 3-lvl htree */
#define EXT4_FEATURE_INCOMPAT_INLINE_DATA 0x8000 /* data in inode */
#define EXT4_FEATURE_INCOMPAT_ENCRYPT   0x10000
#define EXT4_FEATURE_INCOMPAT_CASEFOLD    0x20000

#define EXT4_FEATURE_COMPAT_FUNCS(name, ver, flagname) \
static inline int ext2fs_has_feature_##name(struct ext2_super_block *sb) \
{ \
  return ((EXT2_SB(sb)->s_feature_compat & \
     EXT##ver##_FEATURE_COMPAT_##flagname) != 0); \
} \
static inline void ext2fs_set_feature_##name(struct ext2_super_block *sb) \
{ \
  EXT2_SB(sb)->s_feature_compat |= \
    EXT##ver##_FEATURE_COMPAT_##flagname; \
} \
static inline void ext2fs_clear_feature_##name(struct ext2_super_block *sb) \
{ \
  EXT2_SB(sb)->s_feature_compat &= \
    ~EXT##ver##_FEATURE_COMPAT_##flagname; \
}

#define EXT4_FEATURE_RO_COMPAT_FUNCS(name, ver, flagname) \
static inline int ext2fs_has_feature_##name(struct ext2_super_block *sb) \
{ \
  return ((EXT2_SB(sb)->s_feature_ro_compat & \
     EXT##ver##_FEATURE_RO_COMPAT_##flagname) != 0); \
} \
static inline void ext2fs_set_feature_##name(struct ext2_super_block *sb) \
{ \
  EXT2_SB(sb)->s_feature_ro_compat |= \
    EXT##ver##_FEATURE_RO_COMPAT_##flagname; \
} \
static inline void ext2fs_clear_feature_##name(struct ext2_super_block *sb) \
{ \
  EXT2_SB(sb)->s_feature_ro_compat &= \
    ~EXT##ver##_FEATURE_RO_COMPAT_##flagname; \
}

#define EXT4_FEATURE_INCOMPAT_FUNCS(name, ver, flagname) \
static inline int ext2fs_has_feature_##name(struct ext2_super_block *sb) \
{ \
  return ((EXT2_SB(sb)->s_feature_incompat & \
     EXT##ver##_FEATURE_INCOMPAT_##flagname) != 0); \
} \
static inline void ext2fs_set_feature_##name(struct ext2_super_block *sb) \
{ \
  EXT2_SB(sb)->s_feature_incompat |= \
    EXT##ver##_FEATURE_INCOMPAT_##flagname; \
} \
static inline void ext2fs_clear_feature_##name(struct ext2_super_block *sb) \
{ \
  EXT2_SB(sb)->s_feature_incompat &= \
    ~EXT##ver##_FEATURE_INCOMPAT_##flagname; \
}

EXT4_FEATURE_COMPAT_FUNCS(dir_prealloc,   2, DIR_PREALLOC)
EXT4_FEATURE_COMPAT_FUNCS(imagic_inodes,  2, IMAGIC_INODES)
EXT4_FEATURE_COMPAT_FUNCS(journal,    3, HAS_JOURNAL)
EXT4_FEATURE_COMPAT_FUNCS(xattr,    2, EXT_ATTR)
EXT4_FEATURE_COMPAT_FUNCS(resize_inode,   2, RESIZE_INODE)
EXT4_FEATURE_COMPAT_FUNCS(dir_index,    2, DIR_INDEX)
EXT4_FEATURE_COMPAT_FUNCS(lazy_bg,    2, LAZY_BG)
EXT4_FEATURE_COMPAT_FUNCS(exclude_bitmap, 2, EXCLUDE_BITMAP)
EXT4_FEATURE_COMPAT_FUNCS(sparse_super2,  4, SPARSE_SUPER2)
EXT4_FEATURE_COMPAT_FUNCS(fast_commit,    4, FAST_COMMIT)
EXT4_FEATURE_COMPAT_FUNCS(stable_inodes,  4, STABLE_INODES)
EXT4_FEATURE_COMPAT_FUNCS(orphan_file,    4, ORPHAN_FILE)

EXT4_FEATURE_RO_COMPAT_FUNCS(sparse_super,  2, SPARSE_SUPER)
EXT4_FEATURE_RO_COMPAT_FUNCS(large_file,  2, LARGE_FILE)
EXT4_FEATURE_RO_COMPAT_FUNCS(huge_file,   4, HUGE_FILE)
EXT4_FEATURE_RO_COMPAT_FUNCS(gdt_csum,    4, GDT_CSUM)
EXT4_FEATURE_RO_COMPAT_FUNCS(dir_nlink,   4, DIR_NLINK)
EXT4_FEATURE_RO_COMPAT_FUNCS(extra_isize, 4, EXTRA_ISIZE)
EXT4_FEATURE_RO_COMPAT_FUNCS(has_snapshot,  4, HAS_SNAPSHOT)
EXT4_FEATURE_RO_COMPAT_FUNCS(quota,   4, QUOTA)
EXT4_FEATURE_RO_COMPAT_FUNCS(bigalloc,    4, BIGALLOC)
EXT4_FEATURE_RO_COMPAT_FUNCS(metadata_csum, 4, METADATA_CSUM)
EXT4_FEATURE_RO_COMPAT_FUNCS(replica,   4, REPLICA)
EXT4_FEATURE_RO_COMPAT_FUNCS(readonly,    4, READONLY)
EXT4_FEATURE_RO_COMPAT_FUNCS(project,   4, PROJECT)
EXT4_FEATURE_RO_COMPAT_FUNCS(shared_blocks, 4, SHARED_BLOCKS)
EXT4_FEATURE_RO_COMPAT_FUNCS(verity,    4, VERITY)
EXT4_FEATURE_RO_COMPAT_FUNCS(orphan_present,  4, ORPHAN_PRESENT)

EXT4_FEATURE_INCOMPAT_FUNCS(compression,  2, COMPRESSION)
EXT4_FEATURE_INCOMPAT_FUNCS(filetype,   2, FILETYPE)
EXT4_FEATURE_INCOMPAT_FUNCS(journal_needs_recovery, 3, RECOVER)
EXT4_FEATURE_INCOMPAT_FUNCS(journal_dev,  3, JOURNAL_DEV)
EXT4_FEATURE_INCOMPAT_FUNCS(meta_bg,    2, META_BG)
EXT4_FEATURE_INCOMPAT_FUNCS(extents,    3, EXTENTS)
EXT4_FEATURE_INCOMPAT_FUNCS(64bit,    4, 64BIT)
EXT4_FEATURE_INCOMPAT_FUNCS(mmp,    4, MMP)
EXT4_FEATURE_INCOMPAT_FUNCS(flex_bg,    4, FLEX_BG)
EXT4_FEATURE_INCOMPAT_FUNCS(ea_inode,   4, EA_INODE)
EXT4_FEATURE_INCOMPAT_FUNCS(dirdata,    4, DIRDATA)
EXT4_FEATURE_INCOMPAT_FUNCS(csum_seed,    4, CSUM_SEED)
EXT4_FEATURE_INCOMPAT_FUNCS(largedir,   4, LARGEDIR)
EXT4_FEATURE_INCOMPAT_FUNCS(inline_data,  4, INLINE_DATA)
EXT4_FEATURE_INCOMPAT_FUNCS(encrypt,    4, ENCRYPT)
EXT4_FEATURE_INCOMPAT_FUNCS(casefold,   4, CASEFOLD)

#define EXT2_FEATURE_COMPAT_SUPP  0
#define EXT2_FEATURE_INCOMPAT_SUPP    (EXT2_FEATURE_INCOMPAT_FILETYPE| \
               EXT4_FEATURE_INCOMPAT_MMP| \
               EXT4_FEATURE_INCOMPAT_LARGEDIR| \
               EXT4_FEATURE_INCOMPAT_EA_INODE)
#define EXT2_FEATURE_RO_COMPAT_SUPP (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
           EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
           EXT4_FEATURE_RO_COMPAT_DIR_NLINK| \
           EXT2_FEATURE_RO_COMPAT_BTREE_DIR| \
           EXT4_FEATURE_RO_COMPAT_VERITY)

/*
 * 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
#define EXT3_DEFM_JMODE   0x0060
#define EXT3_DEFM_JMODE_DATA  0x0020
#define EXT3_DEFM_JMODE_ORDERED 0x0040
#define EXT3_DEFM_JMODE_WBACK 0x0060
#define EXT4_DEFM_NOBARRIER 0x0100
#define EXT4_DEFM_BLOCK_VALIDITY 0x0200
#define EXT4_DEFM_DISCARD 0x0400
#define EXT4_DEFM_NODELALLOC  0x0800

static inline int ext4_hash_in_dirent(const struct ext2_inode *inode)
{
  return (inode->i_flags & EXT4_ENCRYPT_FL) &&
    (inode->i_flags & EXT4_CASEFOLD_FL);
}

/*
 * Structure of a directory entry
 */
#define EXT2_NAME_LEN 255

struct ext2_dir_entry {
  __u32 inode;      /* Inode number */
  __u16 rec_len;    /* Directory entry length */
  __u16 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.
 *
 * This structure is deprecated due to endian issues. Please use struct
 * ext2_dir_entry and accessor functions
 *   ext2fs_dirent_name_len
 *   ext2fs_dirent_set_name_len
 *   ext2fs_dirent_file_type
 *   ext2fs_dirent_set_file_type
 * to get and set name_len and file_type fields.
 */
struct ext2_dir_entry_2 {
  __u32 inode;      /* Inode number */
  __u16 rec_len;    /* Directory entry length */
  __u8  name_len;   /* Name length */
  __u8  file_type;
  char  name[EXT2_NAME_LEN];  /* File name */
};

/*
 * Hashes for ext4_dir_entry for casefolded and ecrypted directories.
 * This is located at the first 4 bit aligned location after the name.
 */

struct ext2_dir_entry_hash {
  __le32 hash;
  __le32 minor_hash;
};

#define EXT2_DIRENT_HASHES(entry) \
  ((struct ext2_dir_entry_hash *) &entry->name[\
    (ext2fs_dirent_name_len(entry) + \
      EXT2_DIR_ROUND) & ~EXT2_DIR_ROUND])
#define EXT2_DIRENT_HASH(entry) \
    ext2fs_le32_to_cpu(EXT2_DIRENT_HASHES(entry)->hash)
#define EXT2_DIRENT_MINOR_HASH(entry) \
    ext2fs_le32_to_cpu(EXT2_DIRENT_HASHES(entry)->minor_hash)

/*
 * This is a bogus directory entry at the end of each leaf block that
 * records checksums.
 */
struct ext2_dir_entry_tail {
  __u32 det_reserved_zero1; /* Pretend to be unused */
  __u16 det_rec_len;    /* 12 */
  __u16 det_reserved_name_len;  /* 0xDE00, fake namelen/filetype */
  __u32 det_checksum;   /* crc32c(uuid+inode+dirent) */
};

/*
 * Ext2 directory file types.  Only the low 3 bits are used.  The
 * other bits are reserved for now.
 */
#define EXT2_FT_UNKNOWN   0
#define EXT2_FT_REG_FILE  1
#define EXT2_FT_DIR   2
#define EXT2_FT_CHRDEV    3
#define EXT2_FT_BLKDEV    4
#define EXT2_FT_FIFO    5
#define EXT2_FT_SOCK    6
#define EXT2_FT_SYMLINK   7

#define EXT2_FT_MAX   8

/*
 * Annoyingly, e2fsprogs always swab16s ext2_dir_entry.name_len, so we
 * have to build ext2_dir_entry_tail with that assumption too.  This
 * constant helps to build the dir_entry_tail to look like it has an
 * "invalid" file type.
 */
#define EXT2_DIR_NAME_LEN_CSUM  0xDE00

/*
 * EXT2_DIR_PAD defines the directory entries boundaries
 *
 * NOTE: It must be a multiple of 4
 */
#define EXT2_DIR_ENTRY_HEADER_LEN 8
#define EXT2_DIR_ENTRY_HASH_LEN   8
#define EXT2_DIR_PAD      4
#define EXT2_DIR_ROUND      (EXT2_DIR_PAD - 1)
#define EXT2_DIR_REC_LEN(name_len) ext2fs_dir_rec_len(name_len, 0)

static inline unsigned int ext2fs_dir_rec_len(__u8 name_len,
            int extended)
{
  int rec_len = (name_len + EXT2_DIR_ENTRY_HEADER_LEN + EXT2_DIR_ROUND);

  rec_len &= ~EXT2_DIR_ROUND;
  if (extended)
    rec_len += EXT2_DIR_ENTRY_HASH_LEN;
  return rec_len;
}

#define EXT4_ORPHAN_BLOCK_MAGIC 0x0b10ca04

/* Structure at the tail of orphan block */
struct ext4_orphan_block_tail {
  __le32 ob_magic;
  __le32 ob_checksum;
};

/*
 * Constants for ext4's extended time encoding
 */
#define EXT4_EPOCH_BITS 2
#define EXT4_EPOCH_MASK ((1 << EXT4_EPOCH_BITS) - 1)
#define EXT4_NSEC_MASK  (~0UL << EXT4_EPOCH_BITS)

/*
 * This structure is used for multiple mount protection. It is 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.
 *
 * The timestamp in the MMP structure will be updated by e2fsck at some
 * arbitrary intervals (start of passes, after every few groups of inodes
 * in pass1 and pass1b).  There is no guarantee that e2fsck is updating
 * the MMP block in a timely manner, and the updates it does are purely
 * for the convenience of the sysadmin and not for automatic validation.
 *
 * Note: Only the mmp_seq value is used to determine whether the MMP block
 *  is being updated.  The mmp_time, mmp_nodename, and mmp_bdevname
 *  fields are only for informational purposes for the administrator,
 *  due to clock skew between nodes and hostname HA service takeover.
 */
#define EXT4_MMP_MAGIC     0x004D4D50U /* ASCII for MMP */
#define EXT4_MMP_SEQ_CLEAN 0xFF4D4D50U /* mmp_seq value for clean unmount */
#define EXT4_MMP_SEQ_FSCK  0xE24D4D50U /* mmp_seq value when being fscked */
#define EXT4_MMP_SEQ_MAX   0xE24D4D4FU /* maximum valid mmp_seq value */

/* Not endian-annotated; it's swapped at read/write time */
struct mmp_struct {
  __u32 mmp_magic;    /* Magic number for MMP */
  __u32 mmp_seq;    /* Sequence no. updated periodically */
  __u64 mmp_time;   /* Time last updated (seconds) */
  __u8  mmp_nodename[64] __nonstring; /* Node updating MMP block, no NUL? */
  __u8  mmp_bdevname[32] __nonstring; /* Bdev updating MMP block, no NUL? */
  __u16 mmp_check_interval; /* Changed mmp_check_interval */
  __u16 mmp_pad1;
  __u32 mmp_pad2[226];
  __u32 mmp_checksum;   /* crc32c(uuid+mmp_block) */
};

/*
 * Default interval for MMP update in seconds.
 */
#define EXT4_MMP_UPDATE_INTERVAL  5

/*
 * Maximum interval for MMP update in seconds.
 */
#define EXT4_MMP_MAX_UPDATE_INTERVAL  300

/*
 * Minimum interval for MMP checking in seconds.
 */
#define EXT4_MMP_MIN_CHECK_INTERVAL     5

/*
 * Minimum size of inline data.
 */
#define EXT4_MIN_INLINE_DATA_SIZE ((sizeof(__u32) * EXT2_N_BLOCKS))

/*
 * Size of a parent inode in inline data directory.
 */
#define EXT4_INLINE_DATA_DOTDOT_SIZE  (4)

#define EXT4_ENC_UTF8_12_1  1

#define EXT4_ENC_STRICT_MODE_FL     (1 << 0) /* Reject invalid sequences */

#endif  /* _LINUX_EXT2_FS_H */

Coverage Report

Created: 2026-06-15 06:49