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