fs/ext2/ext2.h

   1 /*
   2  * Copyright (C) 1992, 1993, 1994, 1995
   3  * Remy Card (card@masi.ibp.fr)
   4  * Laboratoire MASI - Institut Blaise Pascal
   5  * Universite Pierre et Marie Curie (Paris VI)
   6  *
   7  *  from
   8  *
   9  *  linux/include/linux/minix_fs.h
  10  *
  11  *  Copyright (C) 1991, 1992  Linus Torvalds
  12  */
  13 #include <linux/fs.h>
  14 #include <linux/ext2_fs.h>
  15 #include <linux/blockgroup_lock.h>
  16 #include <linux/percpu_counter.h>
  17 #include <linux/rbtree.h>
  18
  19 /* XXX Here for now... not interested in restructing headers JUST now */
  20
  21 /* data type for block offset of block group */
  22 typedef int ext2_grpblk_t;
  23
  24 /* data type for filesystem-wide blocks number */
  25 typedef unsigned long ext2_fsblk_t;
  26
  27 #define E2FSBLK "%lu"
  28
  29 struct ext2_reserve_window {
  30         ext2_fsblk_t            _rsv_start;     /* First byte reserved */
  31         ext2_fsblk_t            _rsv_end;       /* Last byte reserved or 0 */
  32 };
  33
  34 struct ext2_reserve_window_node {
  35         struct rb_node          rsv_node;
  36         __u32                   rsv_goal_size;
  37         __u32                   rsv_alloc_hit;
  38         struct ext2_reserve_window      rsv_window;
  39 };
  40
  41 struct ext2_block_alloc_info {
  42         /* information about reservation window */
  43         struct ext2_reserve_window_node rsv_window_node;
  44         /*
  45          * was i_next_alloc_block in ext2_inode_info
  46          * is the logical (file-relative) number of the
  47          * most-recently-allocated block in this file.
  48          * We use this for detecting linearly ascending allocation requests.
  49          */
  50         __u32                   last_alloc_logical_block;
  51         /*
  52          * Was i_next_alloc_goal in ext2_inode_info
  53          * is the *physical* companion to i_next_alloc_block.
  54          * it the the physical block number of the block which was most-recentl
  55          * allocated to this file.  This give us the goal (target) for the next
  56          * allocation when we detect linearly ascending requests.
  57          */
  58         ext2_fsblk_t            last_alloc_physical_block;
  59 };
  60
  61 #define rsv_start rsv_window._rsv_start
  62 #define rsv_end rsv_window._rsv_end
  63
  64 /*
  65  * second extended-fs super-block data in memory
  66  */
  67 struct ext2_sb_info {
  68         unsigned long s_frag_size;      /* Size of a fragment in bytes */
  69         unsigned long s_frags_per_block;/* Number of fragments per block */
  70         unsigned long s_inodes_per_block;/* Number of inodes per block */
  71         unsigned long s_frags_per_group;/* Number of fragments in a group */
  72         unsigned long s_blocks_per_group;/* Number of blocks in a group */
  73         unsigned long s_inodes_per_group;/* Number of inodes in a group */
  74         unsigned long s_itb_per_group;  /* Number of inode table blocks per group */
  75         unsigned long s_gdb_count;      /* Number of group descriptor blocks */
  76         unsigned long s_desc_per_block; /* Number of group descriptors per block */
  77         unsigned long s_groups_count;   /* Number of groups in the fs */
  78         unsigned long s_overhead_last;  /* Last calculated overhead */
  79         unsigned long s_blocks_last;    /* Last seen block count */
  80         struct buffer_head * s_sbh;     /* Buffer containing the super block */
  81         struct ext2_super_block * s_es; /* Pointer to the super block in the buffer */
  82         struct buffer_head ** s_group_desc;
  83         unsigned long  s_mount_opt;
  84         unsigned long s_sb_block;
  85         kuid_t s_resuid;
  86         kgid_t s_resgid;
  87         unsigned short s_mount_state;
  88         unsigned short s_pad;
  89         int s_addr_per_block_bits;
  90         int s_desc_per_block_bits;
  91         int s_inode_size;
  92         int s_first_ino;
  93         spinlock_t s_next_gen_lock;
  94         u32 s_next_generation;
  95         unsigned long s_dir_count;
  96         u8 *s_debts;
  97         struct percpu_counter s_freeblocks_counter;
  98         struct percpu_counter s_freeinodes_counter;
  99         struct percpu_counter s_dirs_counter;
 100         struct blockgroup_lock *s_blockgroup_lock;
 101         /* root of the per fs reservation window tree */
 102         spinlock_t s_rsv_window_lock;
 103         struct rb_root s_rsv_window_root;
 104         struct ext2_reserve_window_node s_rsv_window_head;
 105         /*
 106          * s_lock protects against concurrent modifications of s_mount_state,
 107          * s_blocks_last, s_overhead_last and the content of superblock's
 108          * buffer pointed to by sbi->s_es.
 109          *
 110          * Note: It is used in ext2_show_options() to provide a consistent view
 111          * of the mount options.
 112          */
 113         spinlock_t s_lock;
 114 };
 115
 116 static inline spinlock_t *
 117 sb_bgl_lock(struct ext2_sb_info *sbi, unsigned int block_group)
 118 {
 119         return bgl_lock_ptr(sbi->s_blockgroup_lock, block_group);
 120 }
 121
 122 /*
 123  * Define EXT2FS_DEBUG to produce debug messages
 124  */
 125 #undef EXT2FS_DEBUG
 126
 127 /*
 128  * Define EXT2_RESERVATION to reserve data blocks for expanding files
 129  */
 130 #define EXT2_DEFAULT_RESERVE_BLOCKS     8
 131 /*max window size: 1024(direct blocks) + 3([t,d]indirect blocks) */
 132 #define EXT2_MAX_RESERVE_BLOCKS         1027
 133 #define EXT2_RESERVE_WINDOW_NOT_ALLOCATED 0
 134 /*
 135  * The second extended file system version
 136  */
 137 #define EXT2FS_DATE             "95/08/09"
 138 #define EXT2FS_VERSION          "0.5b"
 139
 140 /*
 141  * Debug code
 142  */
 143 #ifdef EXT2FS_DEBUG
 144 #       define ext2_debug(f, a...)      { \
 145                                         printk ("EXT2-fs DEBUG (%s, %d): %s:", \
 146                                                 __FILE__, __LINE__, __func__); \
 147                                         printk (f, ## a); \
 148                                         }
 149 #else
 150 #       define ext2_debug(f, a...)      /**/
 151 #endif
 152
 153 /*
 154  * Special inode numbers
 155  */
 156 #define EXT2_BAD_INO             1      /* Bad blocks inode */
 157 #define EXT2_ROOT_INO            2      /* Root inode */
 158 #define EXT2_BOOT_LOADER_INO     5      /* Boot loader inode */
 159 #define EXT2_UNDEL_DIR_INO       6      /* Undelete directory inode */
 160
 161 /* First non-reserved inode for old ext2 filesystems */
 162 #define EXT2_GOOD_OLD_FIRST_INO 11
 163
 164 static inline struct ext2_sb_info *EXT2_SB(struct super_block *sb)
 165 {
 166         return sb->s_fs_info;
 167 }
 168
 169 /*
 170  * Macro-instructions used to manage several block sizes
 171  */
 172 #define EXT2_MIN_BLOCK_SIZE             1024
 173 #define EXT2_MAX_BLOCK_SIZE             4096
 174 #define EXT2_MIN_BLOCK_LOG_SIZE           10
 175 #define EXT2_BLOCK_SIZE(s)              ((s)->s_blocksize)
 176 #define EXT2_ADDR_PER_BLOCK(s)          (EXT2_BLOCK_SIZE(s) / sizeof (__u32))
 177 #define EXT2_BLOCK_SIZE_BITS(s)         ((s)->s_blocksize_bits)
 178 #define EXT2_ADDR_PER_BLOCK_BITS(s)     (EXT2_SB(s)->s_addr_per_block_bits)
 179 #define EXT2_INODE_SIZE(s)              (EXT2_SB(s)->s_inode_size)
 180 #define EXT2_FIRST_INO(s)               (EXT2_SB(s)->s_first_ino)
 181
 182 /*
 183  * Macro-instructions used to manage fragments
 184  */
 185 #define EXT2_MIN_FRAG_SIZE              1024
 186 #define EXT2_MAX_FRAG_SIZE              4096
 187 #define EXT2_MIN_FRAG_LOG_SIZE            10
 188 #define EXT2_FRAG_SIZE(s)               (EXT2_SB(s)->s_frag_size)
 189 #define EXT2_FRAGS_PER_BLOCK(s)         (EXT2_SB(s)->s_frags_per_block)
 190
 191 /*
 192  * Structure of a blocks group descriptor
 193  */
 194 struct ext2_group_desc
 195 {
 196         __le32  bg_block_bitmap;                /* Blocks bitmap block */
 197         __le32  bg_inode_bitmap;                /* Inodes bitmap block */
 198         __le32  bg_inode_table;         /* Inodes table block */
 199         __le16  bg_free_blocks_count;   /* Free blocks count */
 200         __le16  bg_free_inodes_count;   /* Free inodes count */
 201         __le16  bg_used_dirs_count;     /* Directories count */
 202         __le16  bg_pad;
 203         __le32  bg_reserved[3];
 204 };
 205
 206 /*
 207  * Macro-instructions used to manage group descriptors
 208  */
 209 #define EXT2_BLOCKS_PER_GROUP(s)        (EXT2_SB(s)->s_blocks_per_group)
 210 #define EXT2_DESC_PER_BLOCK(s)          (EXT2_SB(s)->s_desc_per_block)
 211 #define EXT2_INODES_PER_GROUP(s)        (EXT2_SB(s)->s_inodes_per_group)
 212 #define EXT2_DESC_PER_BLOCK_BITS(s)     (EXT2_SB(s)->s_desc_per_block_bits)
 213
 214 /*
 215  * Constants relative to the data blocks
 216  */
 217 #define EXT2_NDIR_BLOCKS                12
 218 #define EXT2_IND_BLOCK                  EXT2_NDIR_BLOCKS
 219 #define EXT2_DIND_BLOCK                 (EXT2_IND_BLOCK + 1)
 220 #define EXT2_TIND_BLOCK                 (EXT2_DIND_BLOCK + 1)
 221 #define EXT2_N_BLOCKS                   (EXT2_TIND_BLOCK + 1)
 222
 223 /*
 224  * Inode flags (GETFLAGS/SETFLAGS)
 225  */
 226 #define EXT2_SECRM_FL                   FS_SECRM_FL     /* Secure deletion */
 227 #define EXT2_UNRM_FL                    FS_UNRM_FL      /* Undelete */
 228 #define EXT2_COMPR_FL                   FS_COMPR_FL     /* Compress file */
 229 #define EXT2_SYNC_FL                    FS_SYNC_FL      /* Synchronous updates */
 230 #define EXT2_IMMUTABLE_FL               FS_IMMUTABLE_FL /* Immutable file */
 231 #define EXT2_APPEND_FL                  FS_APPEND_FL    /* writes to file may only append */
 232 #define EXT2_NODUMP_FL                  FS_NODUMP_FL    /* do not dump file */
 233 #define EXT2_NOATIME_FL                 FS_NOATIME_FL   /* do not update atime */
 234 /* Reserved for compression usage... */
 235 #define EXT2_DIRTY_FL                   FS_DIRTY_FL
 236 #define EXT2_COMPRBLK_FL                FS_COMPRBLK_FL  /* One or more compressed clusters */
 237 #define EXT2_NOCOMP_FL                  FS_NOCOMP_FL    /* Don't compress */
 238 #define EXT2_ECOMPR_FL                  FS_ECOMPR_FL    /* Compression error */
 239 /* End compression flags --- maybe not all used */
 240 #define EXT2_BTREE_FL                   FS_BTREE_FL     /* btree format dir */
 241 #define EXT2_INDEX_FL                   FS_INDEX_FL     /* hash-indexed directory */
 242 #define EXT2_IMAGIC_FL                  FS_IMAGIC_FL    /* AFS directory */
 243 #define EXT2_JOURNAL_DATA_FL            FS_JOURNAL_DATA_FL /* Reserved for ext3 */
 244 #define EXT2_NOTAIL_FL                  FS_NOTAIL_FL    /* file tail should not be merged */
 245 #define EXT2_DIRSYNC_FL                 FS_DIRSYNC_FL   /* dirsync behaviour (directories only) */
 246 #define EXT2_TOPDIR_FL                  FS_TOPDIR_FL    /* Top of directory hierarchies*/
 247 #define EXT2_RESERVED_FL                FS_RESERVED_FL  /* reserved for ext2 lib */
 248
 249 #define EXT2_FL_USER_VISIBLE            FS_FL_USER_VISIBLE      /* User visible flags */
 250 #define EXT2_FL_USER_MODIFIABLE         FS_FL_USER_MODIFIABLE   /* User modifiable flags */
 251
 252 /* Flags that should be inherited by new inodes from their parent. */
 253 #define EXT2_FL_INHERITED (EXT2_SECRM_FL | EXT2_UNRM_FL | EXT2_COMPR_FL |\
 254                            EXT2_SYNC_FL | EXT2_NODUMP_FL |\
 255                            EXT2_NOATIME_FL | EXT2_COMPRBLK_FL |\
 256                            EXT2_NOCOMP_FL | EXT2_JOURNAL_DATA_FL |\
 257                            EXT2_NOTAIL_FL | EXT2_DIRSYNC_FL)
 258
 259 /* Flags that are appropriate for regular files (all but dir-specific ones). */
 260 #define EXT2_REG_FLMASK (~(EXT2_DIRSYNC_FL | EXT2_TOPDIR_FL))
 261
 262 /* Flags that are appropriate for non-directories/regular files. */
 263 #define EXT2_OTHER_FLMASK (EXT2_NODUMP_FL | EXT2_NOATIME_FL)
 264
 265 /* Mask out flags that are inappropriate for the given type of inode. */
 266 static inline __u32 ext2_mask_flags(umode_t mode, __u32 flags)
 267 {
 268         if (S_ISDIR(mode))
 269                 return flags;
 270         else if (S_ISREG(mode))
 271                 return flags & EXT2_REG_FLMASK;
 272         else
 273                 return flags & EXT2_OTHER_FLMASK;
 274 }
 275
 276 /*
 277  * ioctl commands
 278  */
 279 #define EXT2_IOC_GETFLAGS               FS_IOC_GETFLAGS
 280 #define EXT2_IOC_SETFLAGS               FS_IOC_SETFLAGS
 281 #define EXT2_IOC_GETVERSION             FS_IOC_GETVERSION
 282 #define EXT2_IOC_SETVERSION             FS_IOC_SETVERSION
 283 #define EXT2_IOC_GETRSVSZ               _IOR('f', 5, long)
 284 #define EXT2_IOC_SETRSVSZ               _IOW('f', 6, long)
 285
 286 /*
 287  * ioctl commands in 32 bit emulation
 288  */
 289 #define EXT2_IOC32_GETFLAGS             FS_IOC32_GETFLAGS
 290 #define EXT2_IOC32_SETFLAGS             FS_IOC32_SETFLAGS
 291 #define EXT2_IOC32_GETVERSION           FS_IOC32_GETVERSION
 292 #define EXT2_IOC32_SETVERSION           FS_IOC32_SETVERSION
 293
 294 /*
 295  * Structure of an inode on the disk
 296  */
 297 struct ext2_inode {
 298         __le16  i_mode;         /* File mode */
 299         __le16  i_uid;          /* Low 16 bits of Owner Uid */
 300         __le32  i_size;         /* Size in bytes */
 301         __le32  i_atime;        /* Access time */
 302         __le32  i_ctime;        /* Creation time */
 303         __le32  i_mtime;        /* Modification time */
 304         __le32  i_dtime;        /* Deletion Time */
 305         __le16  i_gid;          /* Low 16 bits of Group Id */
 306         __le16  i_links_count;  /* Links count */
 307         __le32  i_blocks;       /* Blocks count */
 308         __le32  i_flags;        /* File flags */
 309         union {
 310                 struct {
 311                         __le32  l_i_reserved1;
 312                 } linux1;
 313                 struct {
 314                         __le32  h_i_translator;
 315                 } hurd1;
 316                 struct {
 317                         __le32  m_i_reserved1;
 318                 } masix1;
 319         } osd1;                         /* OS dependent 1 */
 320         __le32  i_block[EXT2_N_BLOCKS];/* Pointers to blocks */
 321         __le32  i_generation;   /* File version (for NFS) */
 322         __le32  i_file_acl;     /* File ACL */
 323         __le32  i_dir_acl;      /* Directory ACL */
 324         __le32  i_faddr;        /* Fragment address */
 325         union {
 326                 struct {
 327                         __u8    l_i_frag;       /* Fragment number */
 328                         __u8    l_i_fsize;      /* Fragment size */
 329                         __u16   i_pad1;
 330                         __le16  l_i_uid_high;   /* these 2 fields    */
 331                         __le16  l_i_gid_high;   /* were reserved2[0] */
 332                         __u32   l_i_reserved2;
 333                 } linux2;
 334                 struct {
 335                         __u8    h_i_frag;       /* Fragment number */
 336                         __u8    h_i_fsize;      /* Fragment size */
 337                         __le16  h_i_mode_high;
 338                         __le16  h_i_uid_high;
 339                         __le16  h_i_gid_high;
 340                         __le32  h_i_author;
 341                 } hurd2;
 342                 struct {
 343                         __u8    m_i_frag;       /* Fragment number */
 344                         __u8    m_i_fsize;      /* Fragment size */
 345                         __u16   m_pad1;
 346                         __u32   m_i_reserved2[2];
 347                 } masix2;
 348         } osd2;                         /* OS dependent 2 */
 349 };
 350
 351 #define i_size_high     i_dir_acl
 352
 353 #define i_reserved1     osd1.linux1.l_i_reserved1
 354 #define i_frag          osd2.linux2.l_i_frag
 355 #define i_fsize         osd2.linux2.l_i_fsize
 356 #define i_uid_low       i_uid
 357 #define i_gid_low       i_gid
 358 #define i_uid_high      osd2.linux2.l_i_uid_high
 359 #define i_gid_high      osd2.linux2.l_i_gid_high
 360 #define i_reserved2     osd2.linux2.l_i_reserved2
 361
 362 /*
 363  * File system states
 364  */
 365 #define EXT2_VALID_FS                   0x0001  /* Unmounted cleanly */
 366 #define EXT2_ERROR_FS                   0x0002  /* Errors detected */
 367
 368 /*
 369  * Mount flags
 370  */
 371 #define EXT2_MOUNT_CHECK                0x000001  /* Do mount-time checks */
 372 #define EXT2_MOUNT_OLDALLOC             0x000002  /* Don't use the new Orlov allocator */
 373 #define EXT2_MOUNT_GRPID                0x000004  /* Create files with directory's group */
 374 #define EXT2_MOUNT_DEBUG                0x000008  /* Some debugging messages */
 375 #define EXT2_MOUNT_ERRORS_CONT          0x000010  /* Continue on errors */
 376 #define EXT2_MOUNT_ERRORS_RO            0x000020  /* Remount fs ro on errors */
 377 #define EXT2_MOUNT_ERRORS_PANIC         0x000040  /* Panic on errors */
 378 #define EXT2_MOUNT_MINIX_DF             0x000080  /* Mimics the Minix statfs */
 379 #define EXT2_MOUNT_NOBH                 0x000100  /* No buffer_heads */
 380 #define EXT2_MOUNT_NO_UID32             0x000200  /* Disable 32-bit UIDs */
 381 #define EXT2_MOUNT_XATTR_USER           0x004000  /* Extended user attributes */
 382 #define EXT2_MOUNT_POSIX_ACL            0x008000  /* POSIX Access Control Lists */
 383 #define EXT2_MOUNT_XIP                  0x010000  /* Execute in place */
 384 #define EXT2_MOUNT_USRQUOTA             0x020000  /* user quota */
 385 #define EXT2_MOUNT_GRPQUOTA             0x040000  /* group quota */
 386 #define EXT2_MOUNT_RESERVATION          0x080000  /* Preallocation */
 387
 388
 389 #define clear_opt(o, opt)               o &= ~EXT2_MOUNT_##opt
 390 #define set_opt(o, opt)                 o |= EXT2_MOUNT_##opt
 391 #define test_opt(sb, opt)               (EXT2_SB(sb)->s_mount_opt & \
 392                                          EXT2_MOUNT_##opt)
 393 /*
 394  * Maximal mount counts between two filesystem checks
 395  */
 396 #define EXT2_DFL_MAX_MNT_COUNT          20      /* Allow 20 mounts */
 397 #define EXT2_DFL_CHECKINTERVAL          0       /* Don't use interval check */
 398
 399 /*
 400  * Behaviour when detecting errors
 401  */
 402 #define EXT2_ERRORS_CONTINUE            1       /* Continue execution */
 403 #define EXT2_ERRORS_RO                  2       /* Remount fs read-only */
 404 #define EXT2_ERRORS_PANIC               3       /* Panic */
 405 #define EXT2_ERRORS_DEFAULT             EXT2_ERRORS_CONTINUE
 406
 407 /*
 408  * Structure of the super block
 409  */
 410 struct ext2_super_block {
 411         __le32  s_inodes_count;         /* Inodes count */
 412         __le32  s_blocks_count;         /* Blocks count */
 413         __le32  s_r_blocks_count;       /* Reserved blocks count */
 414         __le32  s_free_blocks_count;    /* Free blocks count */
 415         __le32  s_free_inodes_count;    /* Free inodes count */
 416         __le32  s_first_data_block;     /* First Data Block */
 417         __le32  s_log_block_size;       /* Block size */
 418         __le32  s_log_frag_size;        /* Fragment size */
 419         __le32  s_blocks_per_group;     /* # Blocks per group */
 420         __le32  s_frags_per_group;      /* # Fragments per group */
 421         __le32  s_inodes_per_group;     /* # Inodes per group */
 422         __le32  s_mtime;                /* Mount time */
 423         __le32  s_wtime;                /* Write time */
 424         __le16  s_mnt_count;            /* Mount count */
 425         __le16  s_max_mnt_count;        /* Maximal mount count */
 426         __le16  s_magic;                /* Magic signature */
 427         __le16  s_state;                /* File system state */
 428         __le16  s_errors;               /* Behaviour when detecting errors */
 429         __le16  s_minor_rev_level;      /* minor revision level */
 430         __le32  s_lastcheck;            /* time of last check */
 431         __le32  s_checkinterval;        /* max. time between checks */
 432         __le32  s_creator_os;           /* OS */
 433         __le32  s_rev_level;            /* Revision level */
 434         __le16  s_def_resuid;           /* Default uid for reserved blocks */
 435         __le16  s_def_resgid;           /* Default gid for reserved blocks */
 436         /*
 437          * These fields are for EXT2_DYNAMIC_REV superblocks only.
 438          *
 439          * Note: the difference between the compatible feature set and
 440          * the incompatible feature set is that if there is a bit set
 441          * in the incompatible feature set that the kernel doesn't
 442          * know about, it should refuse to mount the filesystem.
 443          *
 444          * e2fsck's requirements are more strict; if it doesn't know
 445          * about a feature in either the compatible or incompatible
 446          * feature set, it must abort and not try to meddle with
 447          * things it doesn't understand...
 448          */
 449         __le32  s_first_ino;            /* First non-reserved inode */
 450         __le16   s_inode_size;          /* size of inode structure */
 451         __le16  s_block_group_nr;       /* block group # of this superblock */
 452         __le32  s_feature_compat;       /* compatible feature set */
 453         __le32  s_feature_incompat;     /* incompatible feature set */
 454         __le32  s_feature_ro_compat;    /* readonly-compatible feature set */
 455         __u8    s_uuid[16];             /* 128-bit uuid for volume */
 456         char    s_volume_name[16];      /* volume name */
 457         char    s_last_mounted[64];     /* directory where last mounted */
 458         __le32  s_algorithm_usage_bitmap; /* For compression */
 459         /*
 460          * Performance hints.  Directory preallocation should only
 461          * happen if the EXT2_COMPAT_PREALLOC flag is on.
 462          */
 463         __u8    s_prealloc_blocks;      /* Nr of blocks to try to preallocate*/
 464         __u8    s_prealloc_dir_blocks;  /* Nr to preallocate for dirs */
 465         __u16   s_padding1;
 466         /*
 467          * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.
 468          */
 469         __u8    s_journal_uuid[16];     /* uuid of journal superblock */
 470         __u32   s_journal_inum;         /* inode number of journal file */
 471         __u32   s_journal_dev;          /* device number of journal file */
 472         __u32   s_last_orphan;          /* start of list of inodes to delete */
 473         __u32   s_hash_seed[4];         /* HTREE hash seed */
 474         __u8    s_def_hash_version;     /* Default hash version to use */
 475         __u8    s_reserved_char_pad;
 476         __u16   s_reserved_word_pad;
 477         __le32  s_default_mount_opts;
 478         __le32  s_first_meta_bg;        /* First metablock block group */
 479         __u32   s_reserved[190];        /* Padding to the end of the block */
 480 };
 481
 482 /*
 483  * Codes for operating systems
 484  */
 485 #define EXT2_OS_LINUX           0
 486 #define EXT2_OS_HURD            1
 487 #define EXT2_OS_MASIX           2
 488 #define EXT2_OS_FREEBSD         3
 489 #define EXT2_OS_LITES           4
 490
 491 /*
 492  * Revision levels
 493  */
 494 #define EXT2_GOOD_OLD_REV       0       /* The good old (original) format */
 495 #define EXT2_DYNAMIC_REV        1       /* V2 format w/ dynamic inode sizes */
 496
 497 #define EXT2_CURRENT_REV        EXT2_GOOD_OLD_REV
 498 #define EXT2_MAX_SUPP_REV       EXT2_DYNAMIC_REV
 499
 500 #define EXT2_GOOD_OLD_INODE_SIZE 128
 501
 502 /*
 503  * Feature set definitions
 504  */
 505
 506 #define EXT2_HAS_COMPAT_FEATURE(sb,mask)                        \
 507         ( EXT2_SB(sb)->s_es->s_feature_compat & cpu_to_le32(mask) )
 508 #define EXT2_HAS_RO_COMPAT_FEATURE(sb,mask)                     \
 509         ( EXT2_SB(sb)->s_es->s_feature_ro_compat & cpu_to_le32(mask) )
 510 #define EXT2_HAS_INCOMPAT_FEATURE(sb,mask)                      \
 511         ( EXT2_SB(sb)->s_es->s_feature_incompat & cpu_to_le32(mask) )
 512 #define EXT2_SET_COMPAT_FEATURE(sb,mask)                        \
 513         EXT2_SB(sb)->s_es->s_feature_compat |= cpu_to_le32(mask)
 514 #define EXT2_SET_RO_COMPAT_FEATURE(sb,mask)                     \
 515         EXT2_SB(sb)->s_es->s_feature_ro_compat |= cpu_to_le32(mask)
 516 #define EXT2_SET_INCOMPAT_FEATURE(sb,mask)                      \
 517         EXT2_SB(sb)->s_es->s_feature_incompat |= cpu_to_le32(mask)
 518 #define EXT2_CLEAR_COMPAT_FEATURE(sb,mask)                      \
 519         EXT2_SB(sb)->s_es->s_feature_compat &= ~cpu_to_le32(mask)
 520 #define EXT2_CLEAR_RO_COMPAT_FEATURE(sb,mask)                   \
 521         EXT2_SB(sb)->s_es->s_feature_ro_compat &= ~cpu_to_le32(mask)
 522 #define EXT2_CLEAR_INCOMPAT_FEATURE(sb,mask)                    \
 523         EXT2_SB(sb)->s_es->s_feature_incompat &= ~cpu_to_le32(mask)
 524
 525 #define EXT2_FEATURE_COMPAT_DIR_PREALLOC        0x0001
 526 #define EXT2_FEATURE_COMPAT_IMAGIC_INODES       0x0002
 527 #define EXT3_FEATURE_COMPAT_HAS_JOURNAL         0x0004
 528 #define EXT2_FEATURE_COMPAT_EXT_ATTR            0x0008
 529 #define EXT2_FEATURE_COMPAT_RESIZE_INO          0x0010
 530 #define EXT2_FEATURE_COMPAT_DIR_INDEX           0x0020
 531 #define EXT2_FEATURE_COMPAT_ANY                 0xffffffff
 532
 533 #define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER     0x0001
 534 #define EXT2_FEATURE_RO_COMPAT_LARGE_FILE       0x0002
 535 #define EXT2_FEATURE_RO_COMPAT_BTREE_DIR        0x0004
 536 #define EXT2_FEATURE_RO_COMPAT_ANY              0xffffffff
 537
 538 #define EXT2_FEATURE_INCOMPAT_COMPRESSION       0x0001
 539 #define EXT2_FEATURE_INCOMPAT_FILETYPE          0x0002
 540 #define EXT3_FEATURE_INCOMPAT_RECOVER           0x0004
 541 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV       0x0008
 542 #define EXT2_FEATURE_INCOMPAT_META_BG           0x0010
 543 #define EXT2_FEATURE_INCOMPAT_ANY               0xffffffff
 544
 545 #define EXT2_FEATURE_COMPAT_SUPP        EXT2_FEATURE_COMPAT_EXT_ATTR
 546 #define EXT2_FEATURE_INCOMPAT_SUPP      (EXT2_FEATURE_INCOMPAT_FILETYPE| \
 547                                          EXT2_FEATURE_INCOMPAT_META_BG)
 548 #define EXT2_FEATURE_RO_COMPAT_SUPP     (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
 549                                          EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
 550                                          EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
 551 #define EXT2_FEATURE_RO_COMPAT_UNSUPPORTED      ~EXT2_FEATURE_RO_COMPAT_SUPP
 552 #define EXT2_FEATURE_INCOMPAT_UNSUPPORTED       ~EXT2_FEATURE_INCOMPAT_SUPP
 553
 554 /*
 555  * Default values for user and/or group using reserved blocks
 556  */
 557 #define EXT2_DEF_RESUID         0
 558 #define EXT2_DEF_RESGID         0
 559
 560 /*
 561  * Default mount options
 562  */
 563 #define EXT2_DEFM_DEBUG         0x0001
 564 #define EXT2_DEFM_BSDGROUPS     0x0002
 565 #define EXT2_DEFM_XATTR_USER    0x0004
 566 #define EXT2_DEFM_ACL           0x0008
 567 #define EXT2_DEFM_UID16         0x0010
 568     /* Not used by ext2, but reserved for use by ext3 */
 569 #define EXT3_DEFM_JMODE         0x0060
 570 #define EXT3_DEFM_JMODE_DATA    0x0020
 571 #define EXT3_DEFM_JMODE_ORDERED 0x0040
 572 #define EXT3_DEFM_JMODE_WBACK   0x0060
 573
 574 /*
 575  * Structure of a directory entry
 576  */
 577
 578 struct ext2_dir_entry {
 579         __le32  inode;                  /* Inode number */
 580         __le16  rec_len;                /* Directory entry length */
 581         __le16  name_len;               /* Name length */
 582         char    name[];                 /* File name, up to EXT2_NAME_LEN */
 583 };
 584
 585 /*
 586  * The new version of the directory entry.  Since EXT2 structures are
 587  * stored in intel byte order, and the name_len field could never be
 588  * bigger than 255 chars, it's safe to reclaim the extra byte for the
 589  * file_type field.
 590  */
 591 struct ext2_dir_entry_2 {
 592         __le32  inode;                  /* Inode number */
 593         __le16  rec_len;                /* Directory entry length */
 594         __u8    name_len;               /* Name length */
 595         __u8    file_type;
 596         char    name[];                 /* File name, up to EXT2_NAME_LEN */
 597 };
 598
 599 /*
 600  * Ext2 directory file types.  Only the low 3 bits are used.  The
 601  * other bits are reserved for now.
 602  */
 603 enum {
 604         EXT2_FT_UNKNOWN         = 0,
 605         EXT2_FT_REG_FILE        = 1,
 606         EXT2_FT_DIR             = 2,
 607         EXT2_FT_CHRDEV          = 3,
 608         EXT2_FT_BLKDEV          = 4,
 609         EXT2_FT_FIFO            = 5,
 610         EXT2_FT_SOCK            = 6,
 611         EXT2_FT_SYMLINK         = 7,
 612         EXT2_FT_MAX
 613 };
 614
 615 /*
 616  * EXT2_DIR_PAD defines the directory entries boundaries
 617  *
 618  * NOTE: It must be a multiple of 4
 619  */
 620 #define EXT2_DIR_PAD                    4
 621 #define EXT2_DIR_ROUND                  (EXT2_DIR_PAD - 1)
 622 #define EXT2_DIR_REC_LEN(name_len)      (((name_len) + 8 + EXT2_DIR_ROUND) & \
 623                                          ~EXT2_DIR_ROUND)
 624 #define EXT2_MAX_REC_LEN                ((1<<16)-1)
 625
 626 static inline void verify_offsets(void)
 627 {
 628 #define A(x,y) BUILD_BUG_ON(x != offsetof(struct ext2_super_block, y));
 629         A(EXT2_SB_MAGIC_OFFSET, s_magic);
 630         A(EXT2_SB_BLOCKS_OFFSET, s_blocks_count);
 631         A(EXT2_SB_BSIZE_OFFSET, s_log_block_size);
 632 #undef A
 633 }
 634
 635 /*
 636  * ext2 mount options
 637  */
 638 struct ext2_mount_options {
 639         unsigned long s_mount_opt;
 640         kuid_t s_resuid;
 641         kgid_t s_resgid;
 642 };
 643
 644 /*
 645  * second extended file system inode data in memory
 646  */
 647 struct ext2_inode_info {
 648         __le32  i_data[15];
 649         __u32   i_flags;
 650         __u32   i_faddr;
 651         __u8    i_frag_no;
 652         __u8    i_frag_size;
 653         __u16   i_state;
 654         __u32   i_file_acl;
 655         __u32   i_dir_acl;
 656         __u32   i_dtime;
 657
 658         /*
 659          * i_block_group is the number of the block group which contains
 660          * this file's inode.  Constant across the lifetime of the inode,
 661          * it is used for making block allocation decisions - we try to
 662          * place a file's data blocks near its inode block, and new inodes
 663          * near to their parent directory's inode.
 664          */
 665         __u32   i_block_group;
 666
 667         /* block reservation info */
 668         struct ext2_block_alloc_info *i_block_alloc_info;
 669
 670         __u32   i_dir_start_lookup;
 671 #ifdef CONFIG_EXT2_FS_XATTR
 672         /*
 673          * Extended attributes can be read independently of the main file
 674          * data. Taking i_mutex even when reading would cause contention
 675          * between readers of EAs and writers of regular file data, so
 676          * instead we synchronize on xattr_sem when reading or changing
 677          * EAs.
 678          */
 679         struct rw_semaphore xattr_sem;
 680 #endif
 681         rwlock_t i_meta_lock;
 682
 683         /*
 684          * truncate_mutex is for serialising ext2_truncate() against
 685          * ext2_getblock().  It also protects the internals of the inode's
 686          * reservation data structures: ext2_reserve_window and
 687          * ext2_reserve_window_node.
 688          */
 689         struct mutex truncate_mutex;
 690         struct inode    vfs_inode;
 691         struct list_head i_orphan;      /* unlinked but open inodes */
 692 };
 693
 694 /*
 695  * Inode dynamic state flags
 696  */
 697 #define EXT2_STATE_NEW                  0x00000001 /* inode is newly created */
 698
 699
 700 /*
 701  * Function prototypes
 702  */
 703
 704 /*
 705  * Ok, these declarations are also in <linux/kernel.h> but none of the
 706  * ext2 source programs needs to include it so they are duplicated here.
 707  */
 708
 709 static inline struct ext2_inode_info *EXT2_I(struct inode *inode)
 710 {
 711         return container_of(inode, struct ext2_inode_info, vfs_inode);
 712 }
 713
 714 /* balloc.c */
 715 extern int ext2_bg_has_super(struct super_block *sb, int group);
 716 extern unsigned long ext2_bg_num_gdb(struct super_block *sb, int group);
 717 extern ext2_fsblk_t ext2_new_block(struct inode *, unsigned long, int *);
 718 extern ext2_fsblk_t ext2_new_blocks(struct inode *, unsigned long,
 719                                 unsigned long *, int *);
 720 extern void ext2_free_blocks (struct inode *, unsigned long,
 721                               unsigned long);
 722 extern unsigned long ext2_count_free_blocks (struct super_block *);
 723 extern unsigned long ext2_count_dirs (struct super_block *);
 724 extern void ext2_check_blocks_bitmap (struct super_block *);
 725 extern struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb,
 726                                                     unsigned int block_group,
 727                                                     struct buffer_head ** bh);
 728 extern void ext2_discard_reservation (struct inode *);
 729 extern int ext2_should_retry_alloc(struct super_block *sb, int *retries);
 730 extern void ext2_init_block_alloc_info(struct inode *);
 731 extern void ext2_rsv_window_add(struct super_block *sb, struct ext2_reserve_window_node *rsv);
 732
 733 /* dir.c */
 734 extern int ext2_add_link (struct dentry *, struct inode *);
 735 extern ino_t ext2_inode_by_name(struct inode *, struct qstr *);
 736 extern int ext2_make_empty(struct inode *, struct inode *);
 737 extern struct ext2_dir_entry_2 * ext2_find_entry (struct inode *,struct qstr *, struct page **);
 738 extern int ext2_delete_entry (struct ext2_dir_entry_2 *, struct page *);
 739 extern int ext2_empty_dir (struct inode *);
 740 extern struct ext2_dir_entry_2 * ext2_dotdot (struct inode *, struct page **);
 741 extern void ext2_set_link(struct inode *, struct ext2_dir_entry_2 *, struct page *, struct inode *, int);
 742
 743 /* ialloc.c */
 744 extern struct inode * ext2_new_inode (struct inode *, umode_t, const struct qstr *);
 745 extern void ext2_free_inode (struct inode *);
 746 extern unsigned long ext2_count_free_inodes (struct super_block *);
 747 extern void ext2_check_inodes_bitmap (struct super_block *);
 748 extern unsigned long ext2_count_free (struct buffer_head *, unsigned);
 749
 750 /* inode.c */
 751 extern struct inode *ext2_iget (struct super_block *, unsigned long);
 752 extern int ext2_write_inode (struct inode *, struct writeback_control *);
 753 extern void ext2_evict_inode(struct inode *);
 754 extern int ext2_get_block(struct inode *, sector_t, struct buffer_head *, int);
 755 extern int ext2_setattr (struct dentry *, struct iattr *);
 756 extern void ext2_set_inode_flags(struct inode *inode);
 757 extern void ext2_get_inode_flags(struct ext2_inode_info *);
 758 extern int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 759                        u64 start, u64 len);
 760
 761 /* ioctl.c */
 762 extern long ext2_ioctl(struct file *, unsigned int, unsigned long);
 763 extern long ext2_compat_ioctl(struct file *, unsigned int, unsigned long);
 764
 765 /* namei.c */
 766 struct dentry *ext2_get_parent(struct dentry *child);
 767
 768 /* super.c */
 769 extern __printf(3, 4)
 770 void ext2_error(struct super_block *, const char *, const char *, ...);
 771 extern __printf(3, 4)
 772 void ext2_msg(struct super_block *, const char *, const char *, ...);
 773 extern void ext2_update_dynamic_rev (struct super_block *sb);
 774 extern void ext2_write_super (struct super_block *);
 775
 776 /*
 777  * Inodes and files operations
 778  */
 779
 780 /* dir.c */
 781 extern const struct file_operations ext2_dir_operations;
 782
 783 /* file.c */
 784 extern int ext2_fsync(struct file *file, loff_t start, loff_t end,
 785                       int datasync);
 786 extern const struct inode_operations ext2_file_inode_operations;
 787 extern const struct file_operations ext2_file_operations;
 788 extern const struct file_operations ext2_xip_file_operations;
 789
 790 /* inode.c */
 791 extern const struct address_space_operations ext2_aops;
 792 extern const struct address_space_operations ext2_aops_xip;
 793 extern const struct address_space_operations ext2_nobh_aops;
 794
 795 /* namei.c */
 796 extern const struct inode_operations ext2_dir_inode_operations;
 797 extern const struct inode_operations ext2_special_inode_operations;
 798
 799 /* symlink.c */
 800 extern const struct inode_operations ext2_fast_symlink_inode_operations;
 801 extern const struct inode_operations ext2_symlink_inode_operations;
 802
 803 static inline ext2_fsblk_t
 804 ext2_group_first_block_no(struct super_block *sb, unsigned long group_no)
 805 {
 806         return group_no * (ext2_fsblk_t)EXT2_BLOCKS_PER_GROUP(sb) +
 807                 le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block);
 808 }
 809
 810 #define ext2_set_bit    __test_and_set_bit_le
 811 #define ext2_clear_bit  __test_and_clear_bit_le
 812 #define ext2_test_bit   test_bit_le
 813 #define ext2_find_first_zero_bit        find_first_zero_bit_le
 814 #define ext2_find_next_zero_bit         find_next_zero_bit_le