fs/ext2/ext2.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright (C) 1992, 1993, 1994, 1995
   4  * Remy Card (card@masi.ibp.fr)
   5  * Laboratoire MASI - Institut Blaise Pascal
   6  * Universite Pierre et Marie Curie (Paris VI)
   7  *
   8  *  from
   9  *
  10  *  linux/include/linux/minix_fs.h
  11  *
  12  *  Copyright (C) 1991, 1992  Linus Torvalds
  13  */
  14 #include <linux/fs.h>
  15 #include <linux/ext2_fs.h>
  16 #include <linux/blockgroup_lock.h>
  17 #include <linux/percpu_counter.h>
  18 #include <linux/rbtree.h>
  19 #include <linux/mm.h>
  20 #include <linux/highmem.h>
  21
  22 /* XXX Here for now... not interested in restructing headers JUST now */
  23
  24 /* data type for block offset of block group */
  25 typedef int ext2_grpblk_t;
  26
  27 /* data type for filesystem-wide blocks number */
  28 typedef unsigned long ext2_fsblk_t;
  29
  30 #define E2FSBLK "%lu"
  31
  32 struct ext2_reserve_window {
  33         ext2_fsblk_t            _rsv_start;     /* First byte reserved */
  34         ext2_fsblk_t            _rsv_end;       /* Last byte reserved or 0 */
  35 };
  36
  37 struct ext2_reserve_window_node {
  38         struct rb_node          rsv_node;
  39         __u32                   rsv_goal_size;
  40         __u32                   rsv_alloc_hit;
  41         struct ext2_reserve_window      rsv_window;
  42 };
  43
  44 struct ext2_block_alloc_info {
  45         /* information about reservation window */
  46         struct ext2_reserve_window_node rsv_window_node;
  47         /*
  48          * was i_next_alloc_block in ext2_inode_info
  49          * is the logical (file-relative) number of the
  50          * most-recently-allocated block in this file.
  51          * We use this for detecting linearly ascending allocation requests.
  52          */
  53         __u32                   last_alloc_logical_block;
  54         /*
  55          * Was i_next_alloc_goal in ext2_inode_info
  56          * is the *physical* companion to i_next_alloc_block.
  57          * it is the physical block number of the block which was most-recently
  58          * allocated to this file.  This gives us the goal (target) for the next
  59          * allocation when we detect linearly ascending requests.
  60          */
  61         ext2_fsblk_t            last_alloc_physical_block;
  62 };
  63
  64 #define rsv_start rsv_window._rsv_start
  65 #define rsv_end rsv_window._rsv_end
  66
  67 struct mb_cache;
  68
  69 /*
  70  * second extended-fs super-block data in memory
  71  */
  72 struct ext2_sb_info {
  73         unsigned long s_frag_size;      /* Size of a fragment in bytes */
  74         unsigned long s_frags_per_block;/* Number of fragments per block */
  75         unsigned long s_inodes_per_block;/* Number of inodes per block */
  76         unsigned long s_frags_per_group;/* Number of fragments in a group */
  77         unsigned long s_blocks_per_group;/* Number of blocks in a group */
  78         unsigned long s_inodes_per_group;/* Number of inodes in a group */
  79         unsigned long s_itb_per_group;  /* Number of inode table blocks per group */
  80         unsigned long s_gdb_count;      /* Number of group descriptor blocks */
  81         unsigned long s_desc_per_block; /* Number of group descriptors per block */
  82         unsigned long s_groups_count;   /* Number of groups in the fs */
  83         unsigned long s_overhead_last;  /* Last calculated overhead */
  84         unsigned long s_blocks_last;    /* Last seen block count */
  85         struct buffer_head * s_sbh;     /* Buffer containing the super block */
  86         struct ext2_super_block * s_es; /* Pointer to the super block in the buffer */
  87         struct buffer_head ** s_group_desc;
  88         unsigned long  s_mount_opt;
  89         unsigned long s_sb_block;
  90         kuid_t s_resuid;
  91         kgid_t s_resgid;
  92         unsigned short s_mount_state;
  93         unsigned short s_pad;
  94         int s_addr_per_block_bits;
  95         int s_desc_per_block_bits;
  96         int s_inode_size;
  97         int s_first_ino;
  98         spinlock_t s_next_gen_lock;
  99         u32 s_next_generation;
 100         unsigned long s_dir_count;
 101         u8 *s_debts;
 102         struct percpu_counter s_freeblocks_counter;
 103         struct percpu_counter s_freeinodes_counter;
 104         struct percpu_counter s_dirs_counter;
 105         struct blockgroup_lock *s_blockgroup_lock;
 106         /* root of the per fs reservation window tree */
 107         spinlock_t s_rsv_window_lock;
 108         struct rb_root s_rsv_window_root;
 109         struct ext2_reserve_window_node s_rsv_window_head;
 110         /*
 111          * s_lock protects against concurrent modifications of s_mount_state,
 112          * s_blocks_last, s_overhead_last and the content of superblock's
 113          * buffer pointed to by sbi->s_es.
 114          *
 115          * Note: It is used in ext2_show_options() to provide a consistent view
 116          * of the mount options.
 117          */
 118         spinlock_t s_lock;
 119         struct mb_cache *s_ea_block_cache;
 120         struct dax_device *s_daxdev;
 121 };
 122
 123 static inline spinlock_t *
 124 sb_bgl_lock(struct ext2_sb_info *sbi, unsigned int block_group)
 125 {
 126         return bgl_lock_ptr(sbi->s_blockgroup_lock, block_group);
 127 }
 128
 129 /*
 130  * Define EXT2FS_DEBUG to produce debug messages
 131  */
 132 #undef EXT2FS_DEBUG
 133
 134 /*
 135  * Define EXT2_RESERVATION to reserve data blocks for expanding files
 136  */
 137 #define EXT2_DEFAULT_RESERVE_BLOCKS     8
 138 /*max window size: 1024(direct blocks) + 3([t,d]indirect blocks) */
 139 #define EXT2_MAX_RESERVE_BLOCKS         1027
 140 #define EXT2_RESERVE_WINDOW_NOT_ALLOCATED 0
 141 /*
 142  * The second extended file system version
 143  */
 144 #define EXT2FS_DATE             "95/08/09"
 145 #define EXT2FS_VERSION          "0.5b"
 146
 147 /*
 148  * Debug code
 149  */
 150 #ifdef EXT2FS_DEBUG
 151 #       define ext2_debug(f, a...)      { \
 152                                         printk ("EXT2-fs DEBUG (%s, %d): %s:", \
 153                                                 __FILE__, __LINE__, __func__); \
 154                                         printk (f, ## a); \
 155                                         }
 156 #else
 157 #       define ext2_debug(f, a...)      /**/
 158 #endif
 159
 160 /*
 161  * Special inode numbers
 162  */
 163 #define EXT2_BAD_INO             1      /* Bad blocks inode */
 164 #define EXT2_ROOT_INO            2      /* Root inode */
 165 #define EXT2_BOOT_LOADER_INO     5      /* Boot loader inode */
 166 #define EXT2_UNDEL_DIR_INO       6      /* Undelete directory inode */
 167
 168 /* First non-reserved inode for old ext2 filesystems */
 169 #define EXT2_GOOD_OLD_FIRST_INO 11
 170
 171 static inline struct ext2_sb_info *EXT2_SB(struct super_block *sb)
 172 {
 173         return sb->s_fs_info;
 174 }
 175
 176 /*
 177  * Macro-instructions used to manage several block sizes
 178  */
 179 #define EXT2_MIN_BLOCK_SIZE             1024
 180 #define EXT2_MAX_BLOCK_SIZE             4096
 181 #define EXT2_MIN_BLOCK_LOG_SIZE           10
 182 #define EXT2_BLOCK_SIZE(s)              ((s)->s_blocksize)
 183 #define EXT2_ADDR_PER_BLOCK(s)          (EXT2_BLOCK_SIZE(s) / sizeof (__u32))
 184 #define EXT2_BLOCK_SIZE_BITS(s)         ((s)->s_blocksize_bits)
 185 #define EXT2_ADDR_PER_BLOCK_BITS(s)     (EXT2_SB(s)->s_addr_per_block_bits)
 186 #define EXT2_INODE_SIZE(s)              (EXT2_SB(s)->s_inode_size)
 187 #define EXT2_FIRST_INO(s)               (EXT2_SB(s)->s_first_ino)
 188
 189 /*
 190  * Macro-instructions used to manage fragments
 191  */
 192 #define EXT2_MIN_FRAG_SIZE              1024
 193 #define EXT2_MAX_FRAG_SIZE              4096
 194 #define EXT2_MIN_FRAG_LOG_SIZE            10
 195 #define EXT2_FRAG_SIZE(s)               (EXT2_SB(s)->s_frag_size)
 196 #define EXT2_FRAGS_PER_BLOCK(s)         (EXT2_SB(s)->s_frags_per_block)
 197
 198 /*
 199  * Structure of a blocks group descriptor
 200  */
 201 struct ext2_group_desc
 202 {
 203         __le32  bg_block_bitmap;                /* Blocks bitmap block */
 204         __le32  bg_inode_bitmap;                /* Inodes bitmap block */
 205         __le32  bg_inode_table;         /* Inodes table block */
 206         __le16  bg_free_blocks_count;   /* Free blocks count */
 207         __le16  bg_free_inodes_count;   /* Free inodes count */
 208         __le16  bg_used_dirs_count;     /* Directories count */
 209         __le16  bg_pad;
 210         __le32  bg_reserved[3];
 211 };
 212
 213 /*
 214  * Macro-instructions used to manage group descriptors
 215  */
 216 #define EXT2_BLOCKS_PER_GROUP(s)        (EXT2_SB(s)->s_blocks_per_group)
 217 #define EXT2_DESC_PER_BLOCK(s)          (EXT2_SB(s)->s_desc_per_block)
 218 #define EXT2_INODES_PER_GROUP(s)        (EXT2_SB(s)->s_inodes_per_group)
 219 #define EXT2_DESC_PER_BLOCK_BITS(s)     (EXT2_SB(s)->s_desc_per_block_bits)
 220
 221 /*
 222  * Constants relative to the data blocks
 223  */
 224 #define EXT2_NDIR_BLOCKS                12
 225 #define EXT2_IND_BLOCK                  EXT2_NDIR_BLOCKS
 226 #define EXT2_DIND_BLOCK                 (EXT2_IND_BLOCK + 1)
 227 #define EXT2_TIND_BLOCK                 (EXT2_DIND_BLOCK + 1)
 228 #define EXT2_N_BLOCKS                   (EXT2_TIND_BLOCK + 1)
 229
 230 /*
 231  * Inode flags (GETFLAGS/SETFLAGS)
 232  */
 233 #define EXT2_SECRM_FL                   FS_SECRM_FL     /* Secure deletion */
 234 #define EXT2_UNRM_FL                    FS_UNRM_FL      /* Undelete */
 235 #define EXT2_COMPR_FL                   FS_COMPR_FL     /* Compress file */
 236 #define EXT2_SYNC_FL                    FS_SYNC_FL      /* Synchronous updates */
 237 #define EXT2_IMMUTABLE_FL               FS_IMMUTABLE_FL /* Immutable file */
 238 #define EXT2_APPEND_FL                  FS_APPEND_FL    /* writes to file may only append */
 239 #define EXT2_NODUMP_FL                  FS_NODUMP_FL    /* do not dump file */
 240 #define EXT2_NOATIME_FL                 FS_NOATIME_FL   /* do not update atime */
 241 /* Reserved for compression usage... */
 242 #define EXT2_DIRTY_FL                   FS_DIRTY_FL
 243 #define EXT2_COMPRBLK_FL                FS_COMPRBLK_FL  /* One or more compressed clusters */
 244 #define EXT2_NOCOMP_FL                  FS_NOCOMP_FL    /* Don't compress */
 245 #define EXT2_ECOMPR_FL                  FS_ECOMPR_FL    /* Compression error */
 246 /* End compression flags --- maybe not all used */
 247 #define EXT2_BTREE_FL                   FS_BTREE_FL     /* btree format dir */
 248 #define EXT2_INDEX_FL                   FS_INDEX_FL     /* hash-indexed directory */
 249 #define EXT2_IMAGIC_FL                  FS_IMAGIC_FL    /* AFS directory */
 250 #define EXT2_JOURNAL_DATA_FL            FS_JOURNAL_DATA_FL /* Reserved for ext3 */
 251 #define EXT2_NOTAIL_FL                  FS_NOTAIL_FL    /* file tail should not be merged */
 252 #define EXT2_DIRSYNC_FL                 FS_DIRSYNC_FL   /* dirsync behaviour (directories only) */
 253 #define EXT2_TOPDIR_FL                  FS_TOPDIR_FL    /* Top of directory hierarchies*/
 254 #define EXT2_RESERVED_FL                FS_RESERVED_FL  /* reserved for ext2 lib */
 255
 256 #define EXT2_FL_USER_VISIBLE            FS_FL_USER_VISIBLE      /* User visible flags */
 257 #define EXT2_FL_USER_MODIFIABLE         FS_FL_USER_MODIFIABLE   /* User modifiable flags */
 258
 259 /* Flags that should be inherited by new inodes from their parent. */
 260 #define EXT2_FL_INHERITED (EXT2_SECRM_FL | EXT2_UNRM_FL | EXT2_COMPR_FL |\
 261                            EXT2_SYNC_FL | EXT2_NODUMP_FL |\
 262                            EXT2_NOATIME_FL | EXT2_COMPRBLK_FL |\
 263                            EXT2_NOCOMP_FL | EXT2_JOURNAL_DATA_FL |\
 264                            EXT2_NOTAIL_FL | EXT2_DIRSYNC_FL)
 265
 266 /* Flags that are appropriate for regular files (all but dir-specific ones). */
 267 #define EXT2_REG_FLMASK (~(EXT2_DIRSYNC_FL | EXT2_TOPDIR_FL))
 268
 269 /* Flags that are appropriate for non-directories/regular files. */
 270 #define EXT2_OTHER_FLMASK (EXT2_NODUMP_FL | EXT2_NOATIME_FL)
 271
 272 /* Mask out flags that are inappropriate for the given type of inode. */
 273 static inline __u32 ext2_mask_flags(umode_t mode, __u32 flags)
 274 {
 275         if (S_ISDIR(mode))
 276                 return flags;
 277         else if (S_ISREG(mode))
 278                 return flags & EXT2_REG_FLMASK;
 279         else
 280                 return flags & EXT2_OTHER_FLMASK;
 281 }
 282
 283 /*
 284  * ioctl commands
 285  */
 286 #define EXT2_IOC_GETFLAGS               FS_IOC_GETFLAGS
 287 #define EXT2_IOC_SETFLAGS               FS_IOC_SETFLAGS
 288 #define EXT2_IOC_GETVERSION             FS_IOC_GETVERSION
 289 #define EXT2_IOC_SETVERSION             FS_IOC_SETVERSION
 290 #define EXT2_IOC_GETRSVSZ               _IOR('f', 5, long)
 291 #define EXT2_IOC_SETRSVSZ               _IOW('f', 6, long)
 292
 293 /*
 294  * ioctl commands in 32 bit emulation
 295  */
 296 #define EXT2_IOC32_GETFLAGS             FS_IOC32_GETFLAGS
 297 #define EXT2_IOC32_SETFLAGS             FS_IOC32_SETFLAGS
 298 #define EXT2_IOC32_GETVERSION           FS_IOC32_GETVERSION
 299 #define EXT2_IOC32_SETVERSION           FS_IOC32_SETVERSION
 300
 301 /*
 302  * Structure of an inode on the disk
 303  */
 304 struct ext2_inode {
 305         __le16  i_mode;         /* File mode */
 306         __le16  i_uid;          /* Low 16 bits of Owner Uid */
 307         __le32  i_size;         /* Size in bytes */
 308         __le32  i_atime;        /* Access time */
 309         __le32  i_ctime;        /* Creation time */
 310         __le32  i_mtime;        /* Modification time */
 311         __le32  i_dtime;        /* Deletion Time */
 312         __le16  i_gid;          /* Low 16 bits of Group Id */
 313         __le16  i_links_count;  /* Links count */
 314         __le32  i_blocks;       /* Blocks count */
 315         __le32  i_flags;        /* File flags */
 316         union {
 317                 struct {
 318                         __le32  l_i_reserved1;
 319                 } linux1;
 320                 struct {
 321                         __le32  h_i_translator;
 322                 } hurd1;
 323                 struct {
 324                         __le32  m_i_reserved1;
 325                 } masix1;
 326         } osd1;                         /* OS dependent 1 */
 327         __le32  i_block[EXT2_N_BLOCKS];/* Pointers to blocks */
 328         __le32  i_generation;   /* File version (for NFS) */
 329         __le32  i_file_acl;     /* File ACL */
 330         __le32  i_dir_acl;      /* Directory ACL */
 331         __le32  i_faddr;        /* Fragment address */
 332         union {
 333                 struct {
 334                         __u8    l_i_frag;       /* Fragment number */
 335                         __u8    l_i_fsize;      /* Fragment size */
 336                         __u16   i_pad1;
 337                         __le16  l_i_uid_high;   /* these 2 fields    */
 338                         __le16  l_i_gid_high;   /* were reserved2[0] */
 339                         __u32   l_i_reserved2;
 340                 } linux2;
 341                 struct {
 342                         __u8    h_i_frag;       /* Fragment number */
 343                         __u8    h_i_fsize;      /* Fragment size */
 344                         __le16  h_i_mode_high;
 345                         __le16  h_i_uid_high;
 346                         __le16  h_i_gid_high;
 347                         __le32  h_i_author;
 348                 } hurd2;
 349                 struct {
 350                         __u8    m_i_frag;       /* Fragment number */
 351                         __u8    m_i_fsize;      /* Fragment size */
 352                         __u16   m_pad1;
 353                         __u32   m_i_reserved2[2];
 354                 } masix2;
 355         } osd2;                         /* OS dependent 2 */
 356 };
 357
 358 #define i_size_high     i_dir_acl
 359
 360 #define i_reserved1     osd1.linux1.l_i_reserved1
 361 #define i_frag          osd2.linux2.l_i_frag
 362 #define i_fsize         osd2.linux2.l_i_fsize
 363 #define i_uid_low       i_uid
 364 #define i_gid_low       i_gid
 365 #define i_uid_high      osd2.linux2.l_i_uid_high
 366 #define i_gid_high      osd2.linux2.l_i_gid_high
 367 #define i_reserved2     osd2.linux2.l_i_reserved2
 368
 369 /*
 370  * File system states
 371  */
 372 #define EXT2_VALID_FS                   0x0001  /* Unmounted cleanly */
 373 #define EXT2_ERROR_FS                   0x0002  /* Errors detected */
 374 #define EFSCORRUPTED                    EUCLEAN /* Filesystem is corrupted */
 375
 376 /*
 377  * Mount flags
 378  */
 379 #define EXT2_MOUNT_OLDALLOC             0x000002  /* Don't use the new Orlov allocator */
 380 #define EXT2_MOUNT_GRPID                0x000004  /* Create files with directory's group */
 381 #define EXT2_MOUNT_DEBUG                0x000008  /* Some debugging messages */
 382 #define EXT2_MOUNT_ERRORS_CONT          0x000010  /* Continue on errors */
 383 #define EXT2_MOUNT_ERRORS_RO            0x000020  /* Remount fs ro on errors */
 384 #define EXT2_MOUNT_ERRORS_PANIC         0x000040  /* Panic on errors */
 385 #define EXT2_MOUNT_MINIX_DF             0x000080  /* Mimics the Minix statfs */
 386 #define EXT2_MOUNT_NOBH                 0x000100  /* No buffer_heads */
 387 #define EXT2_MOUNT_NO_UID32             0x000200  /* Disable 32-bit UIDs */
 388 #define EXT2_MOUNT_XATTR_USER           0x004000  /* Extended user attributes */
 389 #define EXT2_MOUNT_POSIX_ACL            0x008000  /* POSIX Access Control Lists */
 390 #define EXT2_MOUNT_XIP                  0x010000  /* Obsolete, use DAX */
 391 #define EXT2_MOUNT_USRQUOTA             0x020000  /* user quota */
 392 #define EXT2_MOUNT_GRPQUOTA             0x040000  /* group quota */
 393 #define EXT2_MOUNT_RESERVATION          0x080000  /* Preallocation */
 394 #define EXT2_MOUNT_DAX                  0x100000  /* Direct Access */
 395
 396
 397 #define clear_opt(o, opt)               o &= ~EXT2_MOUNT_##opt
 398 #define set_opt(o, opt)                 o |= EXT2_MOUNT_##opt
 399 #define test_opt(sb, opt)               (EXT2_SB(sb)->s_mount_opt & \
 400                                          EXT2_MOUNT_##opt)
 401 /*
 402  * Maximal mount counts between two filesystem checks
 403  */
 404 #define EXT2_DFL_MAX_MNT_COUNT          20      /* Allow 20 mounts */
 405 #define EXT2_DFL_CHECKINTERVAL          0       /* Don't use interval check */
 406
 407 /*
 408  * Behaviour when detecting errors
 409  */
 410 #define EXT2_ERRORS_CONTINUE            1       /* Continue execution */
 411 #define EXT2_ERRORS_RO                  2       /* Remount fs read-only */
 412 #define EXT2_ERRORS_PANIC               3       /* Panic */
 413 #define EXT2_ERRORS_DEFAULT             EXT2_ERRORS_CONTINUE
 414
 415 /*
 416  * Structure of the super block
 417  */
 418 struct ext2_super_block {
 419         __le32  s_inodes_count;         /* Inodes count */
 420         __le32  s_blocks_count;         /* Blocks count */
 421         __le32  s_r_blocks_count;       /* Reserved blocks count */
 422         __le32  s_free_blocks_count;    /* Free blocks count */
 423         __le32  s_free_inodes_count;    /* Free inodes count */
 424         __le32  s_first_data_block;     /* First Data Block */
 425         __le32  s_log_block_size;       /* Block size */
 426         __le32  s_log_frag_size;        /* Fragment size */
 427         __le32  s_blocks_per_group;     /* # Blocks per group */
 428         __le32  s_frags_per_group;      /* # Fragments per group */
 429         __le32  s_inodes_per_group;     /* # Inodes per group */
 430         __le32  s_mtime;                /* Mount time */
 431         __le32  s_wtime;                /* Write time */
 432         __le16  s_mnt_count;            /* Mount count */
 433         __le16  s_max_mnt_count;        /* Maximal mount count */
 434         __le16  s_magic;                /* Magic signature */
 435         __le16  s_state;                /* File system state */
 436         __le16  s_errors;               /* Behaviour when detecting errors */
 437         __le16  s_minor_rev_level;      /* minor revision level */
 438         __le32  s_lastcheck;            /* time of last check */
 439         __le32  s_checkinterval;        /* max. time between checks */
 440         __le32  s_creator_os;           /* OS */
 441         __le32  s_rev_level;            /* Revision level */
 442         __le16  s_def_resuid;           /* Default uid for reserved blocks */
 443         __le16  s_def_resgid;           /* Default gid for reserved blocks */
 444         /*
 445          * These fields are for EXT2_DYNAMIC_REV superblocks only.
 446          *
 447          * Note: the difference between the compatible feature set and
 448          * the incompatible feature set is that if there is a bit set
 449          * in the incompatible feature set that the kernel doesn't
 450          * know about, it should refuse to mount the filesystem.
 451          *
 452          * e2fsck's requirements are more strict; if it doesn't know
 453          * about a feature in either the compatible or incompatible
 454          * feature set, it must abort and not try to meddle with
 455          * things it doesn't understand...
 456          */
 457         __le32  s_first_ino;            /* First non-reserved inode */
 458         __le16   s_inode_size;          /* size of inode structure */
 459         __le16  s_block_group_nr;       /* block group # of this superblock */
 460         __le32  s_feature_compat;       /* compatible feature set */
 461         __le32  s_feature_incompat;     /* incompatible feature set */
 462         __le32  s_feature_ro_compat;    /* readonly-compatible feature set */
 463         __u8    s_uuid[16];             /* 128-bit uuid for volume */
 464         char    s_volume_name[16];      /* volume name */
 465         char    s_last_mounted[64];     /* directory where last mounted */
 466         __le32  s_algorithm_usage_bitmap; /* For compression */
 467         /*
 468          * Performance hints.  Directory preallocation should only
 469          * happen if the EXT2_COMPAT_PREALLOC flag is on.
 470          */
 471         __u8    s_prealloc_blocks;      /* Nr of blocks to try to preallocate*/
 472         __u8    s_prealloc_dir_blocks;  /* Nr to preallocate for dirs */
 473         __u16   s_padding1;
 474         /*
 475          * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.
 476          */
 477         __u8    s_journal_uuid[16];     /* uuid of journal superblock */
 478         __u32   s_journal_inum;         /* inode number of journal file */
 479         __u32   s_journal_dev;          /* device number of journal file */
 480         __u32   s_last_orphan;          /* start of list of inodes to delete */
 481         __u32   s_hash_seed[4];         /* HTREE hash seed */
 482         __u8    s_def_hash_version;     /* Default hash version to use */
 483         __u8    s_reserved_char_pad;
 484         __u16   s_reserved_word_pad;
 485         __le32  s_default_mount_opts;
 486         __le32  s_first_meta_bg;        /* First metablock block group */
 487         __u32   s_reserved[190];        /* Padding to the end of the block */
 488 };
 489
 490 /*
 491  * Codes for operating systems
 492  */
 493 #define EXT2_OS_LINUX           0
 494 #define EXT2_OS_HURD            1
 495 #define EXT2_OS_MASIX           2
 496 #define EXT2_OS_FREEBSD         3
 497 #define EXT2_OS_LITES           4
 498
 499 /*
 500  * Revision levels
 501  */
 502 #define EXT2_GOOD_OLD_REV       0       /* The good old (original) format */
 503 #define EXT2_DYNAMIC_REV        1       /* V2 format w/ dynamic inode sizes */
 504
 505 #define EXT2_CURRENT_REV        EXT2_GOOD_OLD_REV
 506 #define EXT2_MAX_SUPP_REV       EXT2_DYNAMIC_REV
 507
 508 #define EXT2_GOOD_OLD_INODE_SIZE 128
 509
 510 /*
 511  * Feature set definitions
 512  */
 513
 514 #define EXT2_HAS_COMPAT_FEATURE(sb,mask)                        \
 515         ( EXT2_SB(sb)->s_es->s_feature_compat & cpu_to_le32(mask) )
 516 #define EXT2_HAS_RO_COMPAT_FEATURE(sb,mask)                     \
 517         ( EXT2_SB(sb)->s_es->s_feature_ro_compat & cpu_to_le32(mask) )
 518 #define EXT2_HAS_INCOMPAT_FEATURE(sb,mask)                      \
 519         ( EXT2_SB(sb)->s_es->s_feature_incompat & cpu_to_le32(mask) )
 520 #define EXT2_SET_COMPAT_FEATURE(sb,mask)                        \
 521         EXT2_SB(sb)->s_es->s_feature_compat |= cpu_to_le32(mask)
 522 #define EXT2_SET_RO_COMPAT_FEATURE(sb,mask)                     \
 523         EXT2_SB(sb)->s_es->s_feature_ro_compat |= cpu_to_le32(mask)
 524 #define EXT2_SET_INCOMPAT_FEATURE(sb,mask)                      \
 525         EXT2_SB(sb)->s_es->s_feature_incompat |= cpu_to_le32(mask)
 526 #define EXT2_CLEAR_COMPAT_FEATURE(sb,mask)                      \
 527         EXT2_SB(sb)->s_es->s_feature_compat &= ~cpu_to_le32(mask)
 528 #define EXT2_CLEAR_RO_COMPAT_FEATURE(sb,mask)                   \
 529         EXT2_SB(sb)->s_es->s_feature_ro_compat &= ~cpu_to_le32(mask)
 530 #define EXT2_CLEAR_INCOMPAT_FEATURE(sb,mask)                    \
 531         EXT2_SB(sb)->s_es->s_feature_incompat &= ~cpu_to_le32(mask)
 532
 533 #define EXT2_FEATURE_COMPAT_DIR_PREALLOC        0x0001
 534 #define EXT2_FEATURE_COMPAT_IMAGIC_INODES       0x0002
 535 #define EXT3_FEATURE_COMPAT_HAS_JOURNAL         0x0004
 536 #define EXT2_FEATURE_COMPAT_EXT_ATTR            0x0008
 537 #define EXT2_FEATURE_COMPAT_RESIZE_INO          0x0010
 538 #define EXT2_FEATURE_COMPAT_DIR_INDEX           0x0020
 539 #define EXT2_FEATURE_COMPAT_ANY                 0xffffffff
 540
 541 #define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER     0x0001
 542 #define EXT2_FEATURE_RO_COMPAT_LARGE_FILE       0x0002
 543 #define EXT2_FEATURE_RO_COMPAT_BTREE_DIR        0x0004
 544 #define EXT2_FEATURE_RO_COMPAT_ANY              0xffffffff
 545
 546 #define EXT2_FEATURE_INCOMPAT_COMPRESSION       0x0001
 547 #define EXT2_FEATURE_INCOMPAT_FILETYPE          0x0002
 548 #define EXT3_FEATURE_INCOMPAT_RECOVER           0x0004
 549 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV       0x0008
 550 #define EXT2_FEATURE_INCOMPAT_META_BG           0x0010
 551 #define EXT2_FEATURE_INCOMPAT_ANY               0xffffffff
 552
 553 #define EXT2_FEATURE_COMPAT_SUPP        EXT2_FEATURE_COMPAT_EXT_ATTR
 554 #define EXT2_FEATURE_INCOMPAT_SUPP      (EXT2_FEATURE_INCOMPAT_FILETYPE| \
 555                                          EXT2_FEATURE_INCOMPAT_META_BG)
 556 #define EXT2_FEATURE_RO_COMPAT_SUPP     (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
 557                                          EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
 558                                          EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
 559 #define EXT2_FEATURE_RO_COMPAT_UNSUPPORTED      ~EXT2_FEATURE_RO_COMPAT_SUPP
 560 #define EXT2_FEATURE_INCOMPAT_UNSUPPORTED       ~EXT2_FEATURE_INCOMPAT_SUPP
 561
 562 /*
 563  * Default values for user and/or group using reserved blocks
 564  */
 565 #define EXT2_DEF_RESUID         0
 566 #define EXT2_DEF_RESGID         0
 567
 568 /*
 569  * Default mount options
 570  */
 571 #define EXT2_DEFM_DEBUG         0x0001
 572 #define EXT2_DEFM_BSDGROUPS     0x0002
 573 #define EXT2_DEFM_XATTR_USER    0x0004
 574 #define EXT2_DEFM_ACL           0x0008
 575 #define EXT2_DEFM_UID16         0x0010
 576     /* Not used by ext2, but reserved for use by ext3 */
 577 #define EXT3_DEFM_JMODE         0x0060
 578 #define EXT3_DEFM_JMODE_DATA    0x0020
 579 #define EXT3_DEFM_JMODE_ORDERED 0x0040
 580 #define EXT3_DEFM_JMODE_WBACK   0x0060
 581
 582 /*
 583  * Structure of a directory entry
 584  */
 585
 586 struct ext2_dir_entry {
 587         __le32  inode;                  /* Inode number */
 588         __le16  rec_len;                /* Directory entry length */
 589         __le16  name_len;               /* Name length */
 590         char    name[];                 /* File name, up to EXT2_NAME_LEN */
 591 };
 592
 593 /*
 594  * The new version of the directory entry.  Since EXT2 structures are
 595  * stored in intel byte order, and the name_len field could never be
 596  * bigger than 255 chars, it's safe to reclaim the extra byte for the
 597  * file_type field.
 598  */
 599 struct ext2_dir_entry_2 {
 600         __le32  inode;                  /* Inode number */
 601         __le16  rec_len;                /* Directory entry length */
 602         __u8    name_len;               /* Name length */
 603         __u8    file_type;
 604         char    name[];                 /* File name, up to EXT2_NAME_LEN */
 605 };
 606
 607 /*
 608  * EXT2_DIR_PAD defines the directory entries boundaries
 609  *
 610  * NOTE: It must be a multiple of 4
 611  */
 612 #define EXT2_DIR_PAD                    4
 613 #define EXT2_DIR_ROUND                  (EXT2_DIR_PAD - 1)
 614 #define EXT2_DIR_REC_LEN(name_len)      (((name_len) + 8 + EXT2_DIR_ROUND) & \
 615                                          ~EXT2_DIR_ROUND)
 616 #define EXT2_MAX_REC_LEN                ((1<<16)-1)
 617
 618 static inline void verify_offsets(void)
 619 {
 620 #define A(x,y) BUILD_BUG_ON(x != offsetof(struct ext2_super_block, y));
 621         A(EXT2_SB_MAGIC_OFFSET, s_magic);
 622         A(EXT2_SB_BLOCKS_OFFSET, s_blocks_count);
 623         A(EXT2_SB_BSIZE_OFFSET, s_log_block_size);
 624 #undef A
 625 }
 626
 627 /*
 628  * ext2 mount options
 629  */
 630 struct ext2_mount_options {
 631         unsigned long s_mount_opt;
 632         kuid_t s_resuid;
 633         kgid_t s_resgid;
 634 };
 635
 636 /*
 637  * second extended file system inode data in memory
 638  */
 639 struct ext2_inode_info {
 640         __le32  i_data[15];
 641         __u32   i_flags;
 642         __u32   i_faddr;
 643         __u8    i_frag_no;
 644         __u8    i_frag_size;
 645         __u16   i_state;
 646         __u32   i_file_acl;
 647         __u32   i_dir_acl;
 648         __u32   i_dtime;
 649
 650         /*
 651          * i_block_group is the number of the block group which contains
 652          * this file's inode.  Constant across the lifetime of the inode,
 653          * it is used for making block allocation decisions - we try to
 654          * place a file's data blocks near its inode block, and new inodes
 655          * near to their parent directory's inode.
 656          */
 657         __u32   i_block_group;
 658
 659         /* block reservation info */
 660         struct ext2_block_alloc_info *i_block_alloc_info;
 661
 662         __u32   i_dir_start_lookup;
 663 #ifdef CONFIG_EXT2_FS_XATTR
 664         /*
 665          * Extended attributes can be read independently of the main file
 666          * data. Taking i_mutex even when reading would cause contention
 667          * between readers of EAs and writers of regular file data, so
 668          * instead we synchronize on xattr_sem when reading or changing
 669          * EAs.
 670          */
 671         struct rw_semaphore xattr_sem;
 672 #endif
 673         rwlock_t i_meta_lock;
 674 #ifdef CONFIG_FS_DAX
 675         struct rw_semaphore dax_sem;
 676 #endif
 677
 678         /*
 679          * truncate_mutex is for serialising ext2_truncate() against
 680          * ext2_getblock().  It also protects the internals of the inode's
 681          * reservation data structures: ext2_reserve_window and
 682          * ext2_reserve_window_node.
 683          */
 684         struct mutex truncate_mutex;
 685         struct inode    vfs_inode;
 686         struct list_head i_orphan;      /* unlinked but open inodes */
 687 #ifdef CONFIG_QUOTA
 688         struct dquot *i_dquot[MAXQUOTAS];
 689 #endif
 690 };
 691
 692 #ifdef CONFIG_FS_DAX
 693 #define dax_sem_down_write(ext2_inode)  down_write(&(ext2_inode)->dax_sem)
 694 #define dax_sem_up_write(ext2_inode)    up_write(&(ext2_inode)->dax_sem)
 695 #else
 696 #define dax_sem_down_write(ext2_inode)
 697 #define dax_sem_up_write(ext2_inode)
 698 #endif
 699
 700 /*
 701  * Inode dynamic state flags
 702  */
 703 #define EXT2_STATE_NEW                  0x00000001 /* inode is newly created */
 704
 705
 706 /*
 707  * Function prototypes
 708  */
 709
 710 /*
 711  * Ok, these declarations are also in <linux/kernel.h> but none of the
 712  * ext2 source programs needs to include it so they are duplicated here.
 713  */
 714
 715 static inline struct ext2_inode_info *EXT2_I(struct inode *inode)
 716 {
 717         return container_of(inode, struct ext2_inode_info, vfs_inode);
 718 }
 719
 720 /* balloc.c */
 721 extern int ext2_bg_has_super(struct super_block *sb, int group);
 722 extern unsigned long ext2_bg_num_gdb(struct super_block *sb, int group);
 723 extern ext2_fsblk_t ext2_new_block(struct inode *, unsigned long, int *);
 724 extern ext2_fsblk_t ext2_new_blocks(struct inode *, unsigned long,
 725                                 unsigned long *, int *);
 726 extern int ext2_data_block_valid(struct ext2_sb_info *sbi, ext2_fsblk_t start_blk,
 727                                  unsigned int count);
 728 extern void ext2_free_blocks (struct inode *, unsigned long,
 729                               unsigned long);
 730 extern unsigned long ext2_count_free_blocks (struct super_block *);
 731 extern unsigned long ext2_count_dirs (struct super_block *);
 732 extern struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb,
 733                                                     unsigned int block_group,
 734                                                     struct buffer_head ** bh);
 735 extern void ext2_discard_reservation (struct inode *);
 736 extern int ext2_should_retry_alloc(struct super_block *sb, int *retries);
 737 extern void ext2_init_block_alloc_info(struct inode *);
 738 extern void ext2_rsv_window_add(struct super_block *sb, struct ext2_reserve_window_node *rsv);
 739
 740 /* dir.c */
 741 extern int ext2_add_link (struct dentry *, struct inode *);
 742 extern int ext2_inode_by_name(struct inode *dir,
 743                               const struct qstr *child, ino_t *ino);
 744 extern int ext2_make_empty(struct inode *, struct inode *);
 745 extern struct ext2_dir_entry_2 * ext2_find_entry (struct inode *,const struct qstr *, struct page **);
 746 extern int ext2_delete_entry (struct ext2_dir_entry_2 *, struct page *);
 747 extern int ext2_empty_dir (struct inode *);
 748 extern struct ext2_dir_entry_2 * ext2_dotdot (struct inode *, struct page **);
 749 extern void ext2_set_link(struct inode *, struct ext2_dir_entry_2 *, struct page *, struct inode *, int);
 750 static inline void ext2_put_page(struct page *page)
 751 {
 752         kunmap(page);
 753         put_page(page);
 754 }
 755
 756 /* ialloc.c */
 757 extern struct inode * ext2_new_inode (struct inode *, umode_t, const struct qstr *);
 758 extern void ext2_free_inode (struct inode *);
 759 extern unsigned long ext2_count_free_inodes (struct super_block *);
 760 extern unsigned long ext2_count_free (struct buffer_head *, unsigned);
 761
 762 /* inode.c */
 763 extern struct inode *ext2_iget (struct super_block *, unsigned long);
 764 extern int ext2_write_inode (struct inode *, struct writeback_control *);
 765 extern void ext2_evict_inode(struct inode *);
 766 extern int ext2_get_block(struct inode *, sector_t, struct buffer_head *, int);
 767 extern int ext2_setattr (struct dentry *, struct iattr *);
 768 extern int ext2_getattr (const struct path *, struct kstat *, u32, unsigned int);
 769 extern void ext2_set_inode_flags(struct inode *inode);
 770 extern int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 771                        u64 start, u64 len);
 772
 773 /* ioctl.c */
 774 extern long ext2_ioctl(struct file *, unsigned int, unsigned long);
 775 extern long ext2_compat_ioctl(struct file *, unsigned int, unsigned long);
 776
 777 /* namei.c */
 778 struct dentry *ext2_get_parent(struct dentry *child);
 779
 780 /* super.c */
 781 extern __printf(3, 4)
 782 void ext2_error(struct super_block *, const char *, const char *, ...);
 783 extern __printf(3, 4)
 784 void ext2_msg(struct super_block *, const char *, const char *, ...);
 785 extern void ext2_update_dynamic_rev (struct super_block *sb);
 786 extern void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
 787                             int wait);
 788
 789 /*
 790  * Inodes and files operations
 791  */
 792
 793 /* dir.c */
 794 extern const struct file_operations ext2_dir_operations;
 795
 796 /* file.c */
 797 extern int ext2_fsync(struct file *file, loff_t start, loff_t end,
 798                       int datasync);
 799 extern const struct inode_operations ext2_file_inode_operations;
 800 extern const struct file_operations ext2_file_operations;
 801
 802 /* inode.c */
 803 extern void ext2_set_file_ops(struct inode *inode);
 804 extern const struct address_space_operations ext2_aops;
 805 extern const struct address_space_operations ext2_nobh_aops;
 806 extern const struct iomap_ops ext2_iomap_ops;
 807
 808 /* namei.c */
 809 extern const struct inode_operations ext2_dir_inode_operations;
 810 extern const struct inode_operations ext2_special_inode_operations;
 811
 812 /* symlink.c */
 813 extern const struct inode_operations ext2_fast_symlink_inode_operations;
 814 extern const struct inode_operations ext2_symlink_inode_operations;
 815
 816 static inline ext2_fsblk_t
 817 ext2_group_first_block_no(struct super_block *sb, unsigned long group_no)
 818 {
 819         return group_no * (ext2_fsblk_t)EXT2_BLOCKS_PER_GROUP(sb) +
 820                 le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block);
 821 }
 822
 823 static inline ext2_fsblk_t
 824 ext2_group_last_block_no(struct super_block *sb, unsigned long group_no)
 825 {
 826         struct ext2_sb_info *sbi = EXT2_SB(sb);
 827
 828         if (group_no == sbi->s_groups_count - 1)
 829                 return le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
 830         else
 831                 return ext2_group_first_block_no(sb, group_no) +
 832                         EXT2_BLOCKS_PER_GROUP(sb) - 1;
 833 }
 834
 835 #define ext2_set_bit    __test_and_set_bit_le
 836 #define ext2_clear_bit  __test_and_clear_bit_le
 837 #define ext2_test_bit   test_bit_le
 838 #define ext2_find_first_zero_bit        find_first_zero_bit_le
 839 #define ext2_find_next_zero_bit         find_next_zero_bit_le