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 struct mb_cache;
  65
  66 /*
  67  * second extended-fs super-block data in memory
  68  */
  69 struct ext2_sb_info {
  70         unsigned long s_frag_size;      /* Size of a fragment in bytes */
  71         unsigned long s_frags_per_block;/* Number of fragments per block */
  72         unsigned long s_inodes_per_block;/* Number of inodes per block */
  73         unsigned long s_frags_per_group;/* Number of fragments in a group */
  74         unsigned long s_blocks_per_group;/* Number of blocks in a group */
  75         unsigned long s_inodes_per_group;/* Number of inodes in a group */
  76         unsigned long s_itb_per_group;  /* Number of inode table blocks per group */
  77         unsigned long s_gdb_count;      /* Number of group descriptor blocks */
  78         unsigned long s_desc_per_block; /* Number of group descriptors per block */
  79         unsigned long s_groups_count;   /* Number of groups in the fs */
  80         unsigned long s_overhead_last;  /* Last calculated overhead */
  81         unsigned long s_blocks_last;    /* Last seen block count */
  82         struct buffer_head * s_sbh;     /* Buffer containing the super block */
  83         struct ext2_super_block * s_es; /* Pointer to the super block in the buffer */
  84         struct buffer_head ** s_group_desc;
  85         unsigned long  s_mount_opt;
  86         unsigned long s_sb_block;
  87         kuid_t s_resuid;
  88         kgid_t s_resgid;
  89         unsigned short s_mount_state;
  90         unsigned short s_pad;
  91         int s_addr_per_block_bits;
  92         int s_desc_per_block_bits;
  93         int s_inode_size;
  94         int s_first_ino;
  95         spinlock_t s_next_gen_lock;
  96         u32 s_next_generation;
  97         unsigned long s_dir_count;
  98         u8 *s_debts;
  99         struct percpu_counter s_freeblocks_counter;
 100         struct percpu_counter s_freeinodes_counter;
 101         struct percpu_counter s_dirs_counter;
 102         struct blockgroup_lock *s_blockgroup_lock;
 103         /* root of the per fs reservation window tree */
 104         spinlock_t s_rsv_window_lock;
 105         struct rb_root s_rsv_window_root;
 106         struct ext2_reserve_window_node s_rsv_window_head;
 107         /*
 108          * s_lock protects against concurrent modifications of s_mount_state,
 109          * s_blocks_last, s_overhead_last and the content of superblock's
 110          * buffer pointed to by sbi->s_es.
 111          *
 112          * Note: It is used in ext2_show_options() to provide a consistent view
 113          * of the mount options.
 114          */
 115         spinlock_t s_lock;
 116         struct mb_cache *s_ea_block_cache;
 117 };
 118
 119 static inline spinlock_t *
 120 sb_bgl_lock(struct ext2_sb_info *sbi, unsigned int block_group)
 121 {
 122         return bgl_lock_ptr(sbi->s_blockgroup_lock, block_group);
 123 }
 124
 125 /*
 126  * Define EXT2FS_DEBUG to produce debug messages
 127  */
 128 #undef EXT2FS_DEBUG
 129
 130 /*
 131  * Define EXT2_RESERVATION to reserve data blocks for expanding files
 132  */
 133 #define EXT2_DEFAULT_RESERVE_BLOCKS     8
 134 /*max window size: 1024(direct blocks) + 3([t,d]indirect blocks) */
 135 #define EXT2_MAX_RESERVE_BLOCKS         1027
 136 #define EXT2_RESERVE_WINDOW_NOT_ALLOCATED 0
 137 /*
 138  * The second extended file system version
 139  */
 140 #define EXT2FS_DATE             "95/08/09"
 141 #define EXT2FS_VERSION          "0.5b"
 142
 143 /*
 144  * Debug code
 145  */
 146 #ifdef EXT2FS_DEBUG
 147 #       define ext2_debug(f, a...)      { \
 148                                         printk ("EXT2-fs DEBUG (%s, %d): %s:", \
 149                                                 __FILE__, __LINE__, __func__); \
 150                                         printk (f, ## a); \
 151                                         }
 152 #else
 153 #       define ext2_debug(f, a...)      /**/
 154 #endif
 155
 156 /*
 157  * Special inode numbers
 158  */
 159 #define EXT2_BAD_INO             1      /* Bad blocks inode */
 160 #define EXT2_ROOT_INO            2      /* Root inode */
 161 #define EXT2_BOOT_LOADER_INO     5      /* Boot loader inode */
 162 #define EXT2_UNDEL_DIR_INO       6      /* Undelete directory inode */
 163
 164 /* First non-reserved inode for old ext2 filesystems */
 165 #define EXT2_GOOD_OLD_FIRST_INO 11
 166
 167 static inline struct ext2_sb_info *EXT2_SB(struct super_block *sb)
 168 {
 169         return sb->s_fs_info;
 170 }
 171
 172 /*
 173  * Macro-instructions used to manage several block sizes
 174  */
 175 #define EXT2_MIN_BLOCK_SIZE             1024
 176 #define EXT2_MAX_BLOCK_SIZE             4096
 177 #define EXT2_MIN_BLOCK_LOG_SIZE           10
 178 #define EXT2_BLOCK_SIZE(s)              ((s)->s_blocksize)
 179 #define EXT2_ADDR_PER_BLOCK(s)          (EXT2_BLOCK_SIZE(s) / sizeof (__u32))
 180 #define EXT2_BLOCK_SIZE_BITS(s)         ((s)->s_blocksize_bits)
 181 #define EXT2_ADDR_PER_BLOCK_BITS(s)     (EXT2_SB(s)->s_addr_per_block_bits)
 182 #define EXT2_INODE_SIZE(s)              (EXT2_SB(s)->s_inode_size)
 183 #define EXT2_FIRST_INO(s)               (EXT2_SB(s)->s_first_ino)
 184
 185 /*
 186  * Macro-instructions used to manage fragments
 187  */
 188 #define EXT2_MIN_FRAG_SIZE              1024
 189 #define EXT2_MAX_FRAG_SIZE              4096
 190 #define EXT2_MIN_FRAG_LOG_SIZE            10
 191 #define EXT2_FRAG_SIZE(s)               (EXT2_SB(s)->s_frag_size)
 192 #define EXT2_FRAGS_PER_BLOCK(s)         (EXT2_SB(s)->s_frags_per_block)
 193
 194 /*
 195  * Structure of a blocks group descriptor
 196  */
 197 struct ext2_group_desc
 198 {
 199         __le32  bg_block_bitmap;                /* Blocks bitmap block */
 200         __le32  bg_inode_bitmap;                /* Inodes bitmap block */
 201         __le32  bg_inode_table;         /* Inodes table block */
 202         __le16  bg_free_blocks_count;   /* Free blocks count */
 203         __le16  bg_free_inodes_count;   /* Free inodes count */
 204         __le16  bg_used_dirs_count;     /* Directories count */
 205         __le16  bg_pad;
 206         __le32  bg_reserved[3];
 207 };
 208
 209 /*
 210  * Macro-instructions used to manage group descriptors
 211  */
 212 #define EXT2_BLOCKS_PER_GROUP(s)        (EXT2_SB(s)->s_blocks_per_group)
 213 #define EXT2_DESC_PER_BLOCK(s)          (EXT2_SB(s)->s_desc_per_block)
 214 #define EXT2_INODES_PER_GROUP(s)        (EXT2_SB(s)->s_inodes_per_group)
 215 #define EXT2_DESC_PER_BLOCK_BITS(s)     (EXT2_SB(s)->s_desc_per_block_bits)
 216
 217 /*
 218  * Constants relative to the data blocks
 219  */
 220 #define EXT2_NDIR_BLOCKS                12
 221 #define EXT2_IND_BLOCK                  EXT2_NDIR_BLOCKS
 222 #define EXT2_DIND_BLOCK                 (EXT2_IND_BLOCK + 1)
 223 #define EXT2_TIND_BLOCK                 (EXT2_DIND_BLOCK + 1)
 224 #define EXT2_N_BLOCKS                   (EXT2_TIND_BLOCK + 1)
 225
 226 /*
 227  * Inode flags (GETFLAGS/SETFLAGS)
 228  */
 229 #define EXT2_SECRM_FL                   FS_SECRM_FL     /* Secure deletion */
 230 #define EXT2_UNRM_FL                    FS_UNRM_FL      /* Undelete */
 231 #define EXT2_COMPR_FL                   FS_COMPR_FL     /* Compress file */
 232 #define EXT2_SYNC_FL                    FS_SYNC_FL      /* Synchronous updates */
 233 #define EXT2_IMMUTABLE_FL               FS_IMMUTABLE_FL /* Immutable file */
 234 #define EXT2_APPEND_FL                  FS_APPEND_FL    /* writes to file may only append */
 235 #define EXT2_NODUMP_FL                  FS_NODUMP_FL    /* do not dump file */
 236 #define EXT2_NOATIME_FL                 FS_NOATIME_FL   /* do not update atime */
 237 /* Reserved for compression usage... */
 238 #define EXT2_DIRTY_FL                   FS_DIRTY_FL
 239 #define EXT2_COMPRBLK_FL                FS_COMPRBLK_FL  /* One or more compressed clusters */
 240 #define EXT2_NOCOMP_FL                  FS_NOCOMP_FL    /* Don't compress */
 241 #define EXT2_ECOMPR_FL                  FS_ECOMPR_FL    /* Compression error */
 242 /* End compression flags --- maybe not all used */
 243 #define EXT2_BTREE_FL                   FS_BTREE_FL     /* btree format dir */
 244 #define EXT2_INDEX_FL                   FS_INDEX_FL     /* hash-indexed directory */
 245 #define EXT2_IMAGIC_FL                  FS_IMAGIC_FL    /* AFS directory */
 246 #define EXT2_JOURNAL_DATA_FL            FS_JOURNAL_DATA_FL /* Reserved for ext3 */
 247 #define EXT2_NOTAIL_FL                  FS_NOTAIL_FL    /* file tail should not be merged */
 248 #define EXT2_DIRSYNC_FL                 FS_DIRSYNC_FL   /* dirsync behaviour (directories only) */
 249 #define EXT2_TOPDIR_FL                  FS_TOPDIR_FL    /* Top of directory hierarchies*/
 250 #define EXT2_RESERVED_FL                FS_RESERVED_FL  /* reserved for ext2 lib */
 251
 252 #define EXT2_FL_USER_VISIBLE            FS_FL_USER_VISIBLE      /* User visible flags */
 253 #define EXT2_FL_USER_MODIFIABLE         FS_FL_USER_MODIFIABLE   /* User modifiable flags */
 254
 255 /* Flags that should be inherited by new inodes from their parent. */
 256 #define EXT2_FL_INHERITED (EXT2_SECRM_FL | EXT2_UNRM_FL | EXT2_COMPR_FL |\
 257                            EXT2_SYNC_FL | EXT2_NODUMP_FL |\
 258                            EXT2_NOATIME_FL | EXT2_COMPRBLK_FL |\
 259                            EXT2_NOCOMP_FL | EXT2_JOURNAL_DATA_FL |\
 260                            EXT2_NOTAIL_FL | EXT2_DIRSYNC_FL)
 261
 262 /* Flags that are appropriate for regular files (all but dir-specific ones). */
 263 #define EXT2_REG_FLMASK (~(EXT2_DIRSYNC_FL | EXT2_TOPDIR_FL))
 264
 265 /* Flags that are appropriate for non-directories/regular files. */
 266 #define EXT2_OTHER_FLMASK (EXT2_NODUMP_FL | EXT2_NOATIME_FL)
 267
 268 /* Mask out flags that are inappropriate for the given type of inode. */
 269 static inline __u32 ext2_mask_flags(umode_t mode, __u32 flags)
 270 {
 271         if (S_ISDIR(mode))
 272                 return flags;
 273         else if (S_ISREG(mode))
 274                 return flags & EXT2_REG_FLMASK;
 275         else
 276                 return flags & EXT2_OTHER_FLMASK;
 277 }
 278
 279 /*
 280  * ioctl commands
 281  */
 282 #define EXT2_IOC_GETFLAGS               FS_IOC_GETFLAGS
 283 #define EXT2_IOC_SETFLAGS               FS_IOC_SETFLAGS
 284 #define EXT2_IOC_GETVERSION             FS_IOC_GETVERSION
 285 #define EXT2_IOC_SETVERSION             FS_IOC_SETVERSION
 286 #define EXT2_IOC_GETRSVSZ               _IOR('f', 5, long)
 287 #define EXT2_IOC_SETRSVSZ               _IOW('f', 6, long)
 288
 289 /*
 290  * ioctl commands in 32 bit emulation
 291  */
 292 #define EXT2_IOC32_GETFLAGS             FS_IOC32_GETFLAGS
 293 #define EXT2_IOC32_SETFLAGS             FS_IOC32_SETFLAGS
 294 #define EXT2_IOC32_GETVERSION           FS_IOC32_GETVERSION
 295 #define EXT2_IOC32_SETVERSION           FS_IOC32_SETVERSION
 296
 297 /*
 298  * Structure of an inode on the disk
 299  */
 300 struct ext2_inode {
 301         __le16  i_mode;         /* File mode */
 302         __le16  i_uid;          /* Low 16 bits of Owner Uid */
 303         __le32  i_size;         /* Size in bytes */
 304         __le32  i_atime;        /* Access time */
 305         __le32  i_ctime;        /* Creation time */
 306         __le32  i_mtime;        /* Modification time */
 307         __le32  i_dtime;        /* Deletion Time */
 308         __le16  i_gid;          /* Low 16 bits of Group Id */
 309         __le16  i_links_count;  /* Links count */
 310         __le32  i_blocks;       /* Blocks count */
 311         __le32  i_flags;        /* File flags */
 312         union {
 313                 struct {
 314                         __le32  l_i_reserved1;
 315                 } linux1;
 316                 struct {
 317                         __le32  h_i_translator;
 318                 } hurd1;
 319                 struct {
 320                         __le32  m_i_reserved1;
 321                 } masix1;
 322         } osd1;                         /* OS dependent 1 */
 323         __le32  i_block[EXT2_N_BLOCKS];/* Pointers to blocks */
 324         __le32  i_generation;   /* File version (for NFS) */
 325         __le32  i_file_acl;     /* File ACL */
 326         __le32  i_dir_acl;      /* Directory ACL */
 327         __le32  i_faddr;        /* Fragment address */
 328         union {
 329                 struct {
 330                         __u8    l_i_frag;       /* Fragment number */
 331                         __u8    l_i_fsize;      /* Fragment size */
 332                         __u16   i_pad1;
 333                         __le16  l_i_uid_high;   /* these 2 fields    */
 334                         __le16  l_i_gid_high;   /* were reserved2[0] */
 335                         __u32   l_i_reserved2;
 336                 } linux2;
 337                 struct {
 338                         __u8    h_i_frag;       /* Fragment number */
 339                         __u8    h_i_fsize;      /* Fragment size */
 340                         __le16  h_i_mode_high;
 341                         __le16  h_i_uid_high;
 342                         __le16  h_i_gid_high;
 343                         __le32  h_i_author;
 344                 } hurd2;
 345                 struct {
 346                         __u8    m_i_frag;       /* Fragment number */
 347                         __u8    m_i_fsize;      /* Fragment size */
 348                         __u16   m_pad1;
 349                         __u32   m_i_reserved2[2];
 350                 } masix2;
 351         } osd2;                         /* OS dependent 2 */
 352 };
 353
 354 #define i_size_high     i_dir_acl
 355
 356 #define i_reserved1     osd1.linux1.l_i_reserved1
 357 #define i_frag          osd2.linux2.l_i_frag
 358 #define i_fsize         osd2.linux2.l_i_fsize
 359 #define i_uid_low       i_uid
 360 #define i_gid_low       i_gid
 361 #define i_uid_high      osd2.linux2.l_i_uid_high
 362 #define i_gid_high      osd2.linux2.l_i_gid_high
 363 #define i_reserved2     osd2.linux2.l_i_reserved2
 364
 365 /*
 366  * File system states
 367  */
 368 #define EXT2_VALID_FS                   0x0001  /* Unmounted cleanly */
 369 #define EXT2_ERROR_FS                   0x0002  /* Errors detected */
 370 #define EFSCORRUPTED                    EUCLEAN /* Filesystem is corrupted */
 371
 372 /*
 373  * Mount flags
 374  */
 375 #define EXT2_MOUNT_CHECK                0x000001  /* Do mount-time checks */
 376 #define EXT2_MOUNT_OLDALLOC             0x000002  /* Don't use the new Orlov allocator */
 377 #define EXT2_MOUNT_GRPID                0x000004  /* Create files with directory's group */
 378 #define EXT2_MOUNT_DEBUG                0x000008  /* Some debugging messages */
 379 #define EXT2_MOUNT_ERRORS_CONT          0x000010  /* Continue on errors */
 380 #define EXT2_MOUNT_ERRORS_RO            0x000020  /* Remount fs ro on errors */
 381 #define EXT2_MOUNT_ERRORS_PANIC         0x000040  /* Panic on errors */
 382 #define EXT2_MOUNT_MINIX_DF             0x000080  /* Mimics the Minix statfs */
 383 #define EXT2_MOUNT_NOBH                 0x000100  /* No buffer_heads */
 384 #define EXT2_MOUNT_NO_UID32             0x000200  /* Disable 32-bit UIDs */
 385 #define EXT2_MOUNT_XATTR_USER           0x004000  /* Extended user attributes */
 386 #define EXT2_MOUNT_POSIX_ACL            0x008000  /* POSIX Access Control Lists */
 387 #define EXT2_MOUNT_XIP                  0x010000  /* Obsolete, use DAX */
 388 #define EXT2_MOUNT_USRQUOTA             0x020000  /* user quota */
 389 #define EXT2_MOUNT_GRPQUOTA             0x040000  /* group quota */
 390 #define EXT2_MOUNT_RESERVATION          0x080000  /* Preallocation */
 391 #ifdef CONFIG_FS_DAX
 392 #define EXT2_MOUNT_DAX                  0x100000  /* Direct Access */
 393 #else
 394 #define EXT2_MOUNT_DAX                  0
 395 #endif
 396
 397
 398 #define clear_opt(o, opt)               o &= ~EXT2_MOUNT_##opt
 399 #define set_opt(o, opt)                 o |= EXT2_MOUNT_##opt
 400 #define test_opt(sb, opt)               (EXT2_SB(sb)->s_mount_opt & \
 401                                          EXT2_MOUNT_##opt)
 402 /*
 403  * Maximal mount counts between two filesystem checks
 404  */
 405 #define EXT2_DFL_MAX_MNT_COUNT          20      /* Allow 20 mounts */
 406 #define EXT2_DFL_CHECKINTERVAL          0       /* Don't use interval check */
 407
 408 /*
 409  * Behaviour when detecting errors
 410  */
 411 #define EXT2_ERRORS_CONTINUE            1       /* Continue execution */
 412 #define EXT2_ERRORS_RO                  2       /* Remount fs read-only */
 413 #define EXT2_ERRORS_PANIC               3       /* Panic */
 414 #define EXT2_ERRORS_DEFAULT             EXT2_ERRORS_CONTINUE
 415
 416 /*
 417  * Structure of the super block
 418  */
 419 struct ext2_super_block {
 420         __le32  s_inodes_count;         /* Inodes count */
 421         __le32  s_blocks_count;         /* Blocks count */
 422         __le32  s_r_blocks_count;       /* Reserved blocks count */
 423         __le32  s_free_blocks_count;    /* Free blocks count */
 424         __le32  s_free_inodes_count;    /* Free inodes count */
 425         __le32  s_first_data_block;     /* First Data Block */
 426         __le32  s_log_block_size;       /* Block size */
 427         __le32  s_log_frag_size;        /* Fragment size */
 428         __le32  s_blocks_per_group;     /* # Blocks per group */
 429         __le32  s_frags_per_group;      /* # Fragments per group */
 430         __le32  s_inodes_per_group;     /* # Inodes per group */
 431         __le32  s_mtime;                /* Mount time */
 432         __le32  s_wtime;                /* Write time */
 433         __le16  s_mnt_count;            /* Mount count */
 434         __le16  s_max_mnt_count;        /* Maximal mount count */
 435         __le16  s_magic;                /* Magic signature */
 436         __le16  s_state;                /* File system state */
 437         __le16  s_errors;               /* Behaviour when detecting errors */
 438         __le16  s_minor_rev_level;      /* minor revision level */
 439         __le32  s_lastcheck;            /* time of last check */
 440         __le32  s_checkinterval;        /* max. time between checks */
 441         __le32  s_creator_os;           /* OS */
 442         __le32  s_rev_level;            /* Revision level */
 443         __le16  s_def_resuid;           /* Default uid for reserved blocks */
 444         __le16  s_def_resgid;           /* Default gid for reserved blocks */
 445         /*
 446          * These fields are for EXT2_DYNAMIC_REV superblocks only.
 447          *
 448          * Note: the difference between the compatible feature set and
 449          * the incompatible feature set is that if there is a bit set
 450          * in the incompatible feature set that the kernel doesn't
 451          * know about, it should refuse to mount the filesystem.
 452          *
 453          * e2fsck's requirements are more strict; if it doesn't know
 454          * about a feature in either the compatible or incompatible
 455          * feature set, it must abort and not try to meddle with
 456          * things it doesn't understand...
 457          */
 458         __le32  s_first_ino;            /* First non-reserved inode */
 459         __le16   s_inode_size;          /* size of inode structure */
 460         __le16  s_block_group_nr;       /* block group # of this superblock */
 461         __le32  s_feature_compat;       /* compatible feature set */
 462         __le32  s_feature_incompat;     /* incompatible feature set */
 463         __le32  s_feature_ro_compat;    /* readonly-compatible feature set */
 464         __u8    s_uuid[16];             /* 128-bit uuid for volume */
 465         char    s_volume_name[16];      /* volume name */
 466         char    s_last_mounted[64];     /* directory where last mounted */
 467         __le32  s_algorithm_usage_bitmap; /* For compression */
 468         /*
 469          * Performance hints.  Directory preallocation should only
 470          * happen if the EXT2_COMPAT_PREALLOC flag is on.
 471          */
 472         __u8    s_prealloc_blocks;      /* Nr of blocks to try to preallocate*/
 473         __u8    s_prealloc_dir_blocks;  /* Nr to preallocate for dirs */
 474         __u16   s_padding1;
 475         /*
 476          * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.
 477          */
 478         __u8    s_journal_uuid[16];     /* uuid of journal superblock */
 479         __u32   s_journal_inum;         /* inode number of journal file */
 480         __u32   s_journal_dev;          /* device number of journal file */
 481         __u32   s_last_orphan;          /* start of list of inodes to delete */
 482         __u32   s_hash_seed[4];         /* HTREE hash seed */
 483         __u8    s_def_hash_version;     /* Default hash version to use */
 484         __u8    s_reserved_char_pad;
 485         __u16   s_reserved_word_pad;
 486         __le32  s_default_mount_opts;
 487         __le32  s_first_meta_bg;        /* First metablock block group */
 488         __u32   s_reserved[190];        /* Padding to the end of the block */
 489 };
 490
 491 /*
 492  * Codes for operating systems
 493  */
 494 #define EXT2_OS_LINUX           0
 495 #define EXT2_OS_HURD            1
 496 #define EXT2_OS_MASIX           2
 497 #define EXT2_OS_FREEBSD         3
 498 #define EXT2_OS_LITES           4
 499
 500 /*
 501  * Revision levels
 502  */
 503 #define EXT2_GOOD_OLD_REV       0       /* The good old (original) format */
 504 #define EXT2_DYNAMIC_REV        1       /* V2 format w/ dynamic inode sizes */
 505
 506 #define EXT2_CURRENT_REV        EXT2_GOOD_OLD_REV
 507 #define EXT2_MAX_SUPP_REV       EXT2_DYNAMIC_REV
 508
 509 #define EXT2_GOOD_OLD_INODE_SIZE 128
 510
 511 /*
 512  * Feature set definitions
 513  */
 514
 515 #define EXT2_HAS_COMPAT_FEATURE(sb,mask)                        \
 516         ( EXT2_SB(sb)->s_es->s_feature_compat & cpu_to_le32(mask) )
 517 #define EXT2_HAS_RO_COMPAT_FEATURE(sb,mask)                     \
 518         ( EXT2_SB(sb)->s_es->s_feature_ro_compat & cpu_to_le32(mask) )
 519 #define EXT2_HAS_INCOMPAT_FEATURE(sb,mask)                      \
 520         ( EXT2_SB(sb)->s_es->s_feature_incompat & cpu_to_le32(mask) )
 521 #define EXT2_SET_COMPAT_FEATURE(sb,mask)                        \
 522         EXT2_SB(sb)->s_es->s_feature_compat |= cpu_to_le32(mask)
 523 #define EXT2_SET_RO_COMPAT_FEATURE(sb,mask)                     \
 524         EXT2_SB(sb)->s_es->s_feature_ro_compat |= cpu_to_le32(mask)
 525 #define EXT2_SET_INCOMPAT_FEATURE(sb,mask)                      \
 526         EXT2_SB(sb)->s_es->s_feature_incompat |= cpu_to_le32(mask)
 527 #define EXT2_CLEAR_COMPAT_FEATURE(sb,mask)                      \
 528         EXT2_SB(sb)->s_es->s_feature_compat &= ~cpu_to_le32(mask)
 529 #define EXT2_CLEAR_RO_COMPAT_FEATURE(sb,mask)                   \
 530         EXT2_SB(sb)->s_es->s_feature_ro_compat &= ~cpu_to_le32(mask)
 531 #define EXT2_CLEAR_INCOMPAT_FEATURE(sb,mask)                    \
 532         EXT2_SB(sb)->s_es->s_feature_incompat &= ~cpu_to_le32(mask)
 533
 534 #define EXT2_FEATURE_COMPAT_DIR_PREALLOC        0x0001
 535 #define EXT2_FEATURE_COMPAT_IMAGIC_INODES       0x0002
 536 #define EXT3_FEATURE_COMPAT_HAS_JOURNAL         0x0004
 537 #define EXT2_FEATURE_COMPAT_EXT_ATTR            0x0008
 538 #define EXT2_FEATURE_COMPAT_RESIZE_INO          0x0010
 539 #define EXT2_FEATURE_COMPAT_DIR_INDEX           0x0020
 540 #define EXT2_FEATURE_COMPAT_ANY                 0xffffffff
 541
 542 #define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER     0x0001
 543 #define EXT2_FEATURE_RO_COMPAT_LARGE_FILE       0x0002
 544 #define EXT2_FEATURE_RO_COMPAT_BTREE_DIR        0x0004
 545 #define EXT2_FEATURE_RO_COMPAT_ANY              0xffffffff
 546
 547 #define EXT2_FEATURE_INCOMPAT_COMPRESSION       0x0001
 548 #define EXT2_FEATURE_INCOMPAT_FILETYPE          0x0002
 549 #define EXT3_FEATURE_INCOMPAT_RECOVER           0x0004
 550 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV       0x0008
 551 #define EXT2_FEATURE_INCOMPAT_META_BG           0x0010
 552 #define EXT2_FEATURE_INCOMPAT_ANY               0xffffffff
 553
 554 #define EXT2_FEATURE_COMPAT_SUPP        EXT2_FEATURE_COMPAT_EXT_ATTR
 555 #define EXT2_FEATURE_INCOMPAT_SUPP      (EXT2_FEATURE_INCOMPAT_FILETYPE| \
 556                                          EXT2_FEATURE_INCOMPAT_META_BG)
 557 #define EXT2_FEATURE_RO_COMPAT_SUPP     (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
 558                                          EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
 559                                          EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
 560 #define EXT2_FEATURE_RO_COMPAT_UNSUPPORTED      ~EXT2_FEATURE_RO_COMPAT_SUPP
 561 #define EXT2_FEATURE_INCOMPAT_UNSUPPORTED       ~EXT2_FEATURE_INCOMPAT_SUPP
 562
 563 /*
 564  * Default values for user and/or group using reserved blocks
 565  */
 566 #define EXT2_DEF_RESUID         0
 567 #define EXT2_DEF_RESGID         0
 568
 569 /*
 570  * Default mount options
 571  */
 572 #define EXT2_DEFM_DEBUG         0x0001
 573 #define EXT2_DEFM_BSDGROUPS     0x0002
 574 #define EXT2_DEFM_XATTR_USER    0x0004
 575 #define EXT2_DEFM_ACL           0x0008
 576 #define EXT2_DEFM_UID16         0x0010
 577     /* Not used by ext2, but reserved for use by ext3 */
 578 #define EXT3_DEFM_JMODE         0x0060
 579 #define EXT3_DEFM_JMODE_DATA    0x0020
 580 #define EXT3_DEFM_JMODE_ORDERED 0x0040
 581 #define EXT3_DEFM_JMODE_WBACK   0x0060
 582
 583 /*
 584  * Structure of a directory entry
 585  */
 586
 587 struct ext2_dir_entry {
 588         __le32  inode;                  /* Inode number */
 589         __le16  rec_len;                /* Directory entry length */
 590         __le16  name_len;               /* Name length */
 591         char    name[];                 /* File name, up to EXT2_NAME_LEN */
 592 };
 593
 594 /*
 595  * The new version of the directory entry.  Since EXT2 structures are
 596  * stored in intel byte order, and the name_len field could never be
 597  * bigger than 255 chars, it's safe to reclaim the extra byte for the
 598  * file_type field.
 599  */
 600 struct ext2_dir_entry_2 {
 601         __le32  inode;                  /* Inode number */
 602         __le16  rec_len;                /* Directory entry length */
 603         __u8    name_len;               /* Name length */
 604         __u8    file_type;
 605         char    name[];                 /* File name, up to EXT2_NAME_LEN */
 606 };
 607
 608 /*
 609  * Ext2 directory file types.  Only the low 3 bits are used.  The
 610  * other bits are reserved for now.
 611  */
 612 enum {
 613         EXT2_FT_UNKNOWN         = 0,
 614         EXT2_FT_REG_FILE        = 1,
 615         EXT2_FT_DIR             = 2,
 616         EXT2_FT_CHRDEV          = 3,
 617         EXT2_FT_BLKDEV          = 4,
 618         EXT2_FT_FIFO            = 5,
 619         EXT2_FT_SOCK            = 6,
 620         EXT2_FT_SYMLINK         = 7,
 621         EXT2_FT_MAX
 622 };
 623
 624 /*
 625  * EXT2_DIR_PAD defines the directory entries boundaries
 626  *
 627  * NOTE: It must be a multiple of 4
 628  */
 629 #define EXT2_DIR_PAD                    4
 630 #define EXT2_DIR_ROUND                  (EXT2_DIR_PAD - 1)
 631 #define EXT2_DIR_REC_LEN(name_len)      (((name_len) + 8 + EXT2_DIR_ROUND) & \
 632                                          ~EXT2_DIR_ROUND)
 633 #define EXT2_MAX_REC_LEN                ((1<<16)-1)
 634
 635 static inline void verify_offsets(void)
 636 {
 637 #define A(x,y) BUILD_BUG_ON(x != offsetof(struct ext2_super_block, y));
 638         A(EXT2_SB_MAGIC_OFFSET, s_magic);
 639         A(EXT2_SB_BLOCKS_OFFSET, s_blocks_count);
 640         A(EXT2_SB_BSIZE_OFFSET, s_log_block_size);
 641 #undef A
 642 }
 643
 644 /*
 645  * ext2 mount options
 646  */
 647 struct ext2_mount_options {
 648         unsigned long s_mount_opt;
 649         kuid_t s_resuid;
 650         kgid_t s_resgid;
 651 };
 652
 653 /*
 654  * second extended file system inode data in memory
 655  */
 656 struct ext2_inode_info {
 657         __le32  i_data[15];
 658         __u32   i_flags;
 659         __u32   i_faddr;
 660         __u8    i_frag_no;
 661         __u8    i_frag_size;
 662         __u16   i_state;
 663         __u32   i_file_acl;
 664         __u32   i_dir_acl;
 665         __u32   i_dtime;
 666
 667         /*
 668          * i_block_group is the number of the block group which contains
 669          * this file's inode.  Constant across the lifetime of the inode,
 670          * it is used for making block allocation decisions - we try to
 671          * place a file's data blocks near its inode block, and new inodes
 672          * near to their parent directory's inode.
 673          */
 674         __u32   i_block_group;
 675
 676         /* block reservation info */
 677         struct ext2_block_alloc_info *i_block_alloc_info;
 678
 679         __u32   i_dir_start_lookup;
 680 #ifdef CONFIG_EXT2_FS_XATTR
 681         /*
 682          * Extended attributes can be read independently of the main file
 683          * data. Taking i_mutex even when reading would cause contention
 684          * between readers of EAs and writers of regular file data, so
 685          * instead we synchronize on xattr_sem when reading or changing
 686          * EAs.
 687          */
 688         struct rw_semaphore xattr_sem;
 689 #endif
 690         rwlock_t i_meta_lock;
 691 #ifdef CONFIG_FS_DAX
 692         struct rw_semaphore dax_sem;
 693 #endif
 694
 695         /*
 696          * truncate_mutex is for serialising ext2_truncate() against
 697          * ext2_getblock().  It also protects the internals of the inode's
 698          * reservation data structures: ext2_reserve_window and
 699          * ext2_reserve_window_node.
 700          */
 701         struct mutex truncate_mutex;
 702         struct inode    vfs_inode;
 703         struct list_head i_orphan;      /* unlinked but open inodes */
 704 #ifdef CONFIG_QUOTA
 705         struct dquot *i_dquot[MAXQUOTAS];
 706 #endif
 707 };
 708
 709 #ifdef CONFIG_FS_DAX
 710 #define dax_sem_down_write(ext2_inode)  down_write(&(ext2_inode)->dax_sem)
 711 #define dax_sem_up_write(ext2_inode)    up_write(&(ext2_inode)->dax_sem)
 712 #else
 713 #define dax_sem_down_write(ext2_inode)
 714 #define dax_sem_up_write(ext2_inode)
 715 #endif
 716
 717 /*
 718  * Inode dynamic state flags
 719  */
 720 #define EXT2_STATE_NEW                  0x00000001 /* inode is newly created */
 721
 722
 723 /*
 724  * Function prototypes
 725  */
 726
 727 /*
 728  * Ok, these declarations are also in <linux/kernel.h> but none of the
 729  * ext2 source programs needs to include it so they are duplicated here.
 730  */
 731
 732 static inline struct ext2_inode_info *EXT2_I(struct inode *inode)
 733 {
 734         return container_of(inode, struct ext2_inode_info, vfs_inode);
 735 }
 736
 737 /* balloc.c */
 738 extern int ext2_bg_has_super(struct super_block *sb, int group);
 739 extern unsigned long ext2_bg_num_gdb(struct super_block *sb, int group);
 740 extern ext2_fsblk_t ext2_new_block(struct inode *, unsigned long, int *);
 741 extern ext2_fsblk_t ext2_new_blocks(struct inode *, unsigned long,
 742                                 unsigned long *, int *);
 743 extern int ext2_data_block_valid(struct ext2_sb_info *sbi, ext2_fsblk_t start_blk,
 744                                  unsigned int count);
 745 extern void ext2_free_blocks (struct inode *, unsigned long,
 746                               unsigned long);
 747 extern unsigned long ext2_count_free_blocks (struct super_block *);
 748 extern unsigned long ext2_count_dirs (struct super_block *);
 749 extern void ext2_check_blocks_bitmap (struct super_block *);
 750 extern struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb,
 751                                                     unsigned int block_group,
 752                                                     struct buffer_head ** bh);
 753 extern void ext2_discard_reservation (struct inode *);
 754 extern int ext2_should_retry_alloc(struct super_block *sb, int *retries);
 755 extern void ext2_init_block_alloc_info(struct inode *);
 756 extern void ext2_rsv_window_add(struct super_block *sb, struct ext2_reserve_window_node *rsv);
 757
 758 /* dir.c */
 759 extern int ext2_add_link (struct dentry *, struct inode *);
 760 extern ino_t ext2_inode_by_name(struct inode *, const struct qstr *);
 761 extern int ext2_make_empty(struct inode *, struct inode *);
 762 extern struct ext2_dir_entry_2 * ext2_find_entry (struct inode *,const struct qstr *, struct page **);
 763 extern int ext2_delete_entry (struct ext2_dir_entry_2 *, struct page *);
 764 extern int ext2_empty_dir (struct inode *);
 765 extern struct ext2_dir_entry_2 * ext2_dotdot (struct inode *, struct page **);
 766 extern void ext2_set_link(struct inode *, struct ext2_dir_entry_2 *, struct page *, struct inode *, int);
 767
 768 /* ialloc.c */
 769 extern struct inode * ext2_new_inode (struct inode *, umode_t, const struct qstr *);
 770 extern void ext2_free_inode (struct inode *);
 771 extern unsigned long ext2_count_free_inodes (struct super_block *);
 772 extern void ext2_check_inodes_bitmap (struct super_block *);
 773 extern unsigned long ext2_count_free (struct buffer_head *, unsigned);
 774
 775 /* inode.c */
 776 extern struct inode *ext2_iget (struct super_block *, unsigned long);
 777 extern int ext2_write_inode (struct inode *, struct writeback_control *);
 778 extern void ext2_evict_inode(struct inode *);
 779 extern int ext2_get_block(struct inode *, sector_t, struct buffer_head *, int);
 780 extern int ext2_setattr (struct dentry *, struct iattr *);
 781 extern void ext2_set_inode_flags(struct inode *inode);
 782 extern int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 783                        u64 start, u64 len);
 784
 785 /* ioctl.c */
 786 extern long ext2_ioctl(struct file *, unsigned int, unsigned long);
 787 extern long ext2_compat_ioctl(struct file *, unsigned int, unsigned long);
 788
 789 /* namei.c */
 790 struct dentry *ext2_get_parent(struct dentry *child);
 791
 792 /* super.c */
 793 extern __printf(3, 4)
 794 void ext2_error(struct super_block *, const char *, const char *, ...);
 795 extern __printf(3, 4)
 796 void ext2_msg(struct super_block *, const char *, const char *, ...);
 797 extern void ext2_update_dynamic_rev (struct super_block *sb);
 798 extern void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
 799                             int wait);
 800
 801 /*
 802  * Inodes and files operations
 803  */
 804
 805 /* dir.c */
 806 extern const struct file_operations ext2_dir_operations;
 807
 808 /* file.c */
 809 extern int ext2_fsync(struct file *file, loff_t start, loff_t end,
 810                       int datasync);
 811 extern const struct inode_operations ext2_file_inode_operations;
 812 extern const struct file_operations ext2_file_operations;
 813
 814 /* inode.c */
 815 extern const struct address_space_operations ext2_aops;
 816 extern const struct address_space_operations ext2_nobh_aops;
 817 extern const struct iomap_ops ext2_iomap_ops;
 818
 819 /* namei.c */
 820 extern const struct inode_operations ext2_dir_inode_operations;
 821 extern const struct inode_operations ext2_special_inode_operations;
 822
 823 /* symlink.c */
 824 extern const struct inode_operations ext2_fast_symlink_inode_operations;
 825 extern const struct inode_operations ext2_symlink_inode_operations;
 826
 827 static inline ext2_fsblk_t
 828 ext2_group_first_block_no(struct super_block *sb, unsigned long group_no)
 829 {
 830         return group_no * (ext2_fsblk_t)EXT2_BLOCKS_PER_GROUP(sb) +
 831                 le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block);
 832 }
 833
 834 #define ext2_set_bit    __test_and_set_bit_le
 835 #define ext2_clear_bit  __test_and_clear_bit_le
 836 #define ext2_test_bit   test_bit_le
 837 #define ext2_find_first_zero_bit        find_first_zero_bit_le
 838 #define ext2_find_next_zero_bit         find_next_zero_bit_le