include/linux/sysv_fs.h

   1 #ifndef _LINUX_SYSV_FS_H
   2 #define _LINUX_SYSV_FS_H
   3
   4 /*
   5  * The SystemV/Coherent filesystem constants/structures/macros
   6  */
   7
   8
   9 /* This code assumes
  10    - a little endian processor like 386,
  11    - sizeof(short) = 2, sizeof(int) = 4, sizeof(long) = 4,
  12    - alignof(short) = 2, alignof(long) = 4.
  13 */
  14
  15 #ifdef __GNUC__
  16 #define __packed2__  __attribute__ ((packed, aligned(2)))
  17 #else
  18 #error I want gcc!
  19 #endif
  20
  21 #include <linux/stat.h>         /* declares S_IFLNK etc. */
  22 #include <linux/sched.h>        /* declares wake_up() */
  23 #include <linux/sysv_fs_sb.h>   /* defines the sv_... shortcuts */
  24
  25
  26 /* Layout on disk */
  27 /* ============== */
  28
  29
  30 /* The block size is sb->sv_block_size which may be smaller than BLOCK_SIZE. */
  31
  32 /* zones (= data allocation units) are blocks */
  33
  34 /* On Coherent FS, 32 bit quantities are stored using (I quote the Coherent
  35    manual) a "canonical byte ordering". This is the PDP-11 byte ordering:
  36    x = 2^24 * byte3 + 2^16 * byte2 + 2^8 * byte1 + byte0 is stored
  37    as { byte2, byte3, byte0, byte1 }. We need conversions.
  38 */
  39
  40 typedef u32 coh_ulong;
  41
  42 static inline coh_ulong to_coh_ulong (u32 x)
  43 {
  44         return ((x & 0xffff) << 16) | ((x & 0xffff0000) >> 16);
  45 }
  46
  47 static inline u32 from_coh_ulong (coh_ulong x)
  48 {
  49         return ((x & 0xffff) << 16) | ((x & 0xffff0000) >> 16);
  50 }
  51
  52 /* inode numbers are 16 bit */
  53
  54 typedef u16 sysv_ino_t;
  55
  56 /* Block numbers are 24 bit, sometimes stored in 32 bit.
  57    On Coherent FS, they are always stored in PDP-11 manner: the least
  58    significant 16 bits come last.
  59 */
  60
  61 typedef u32 sysv_zone_t;
  62
  63 /* Among the blocks ... */
  64 /* Xenix FS, Coherent FS: block 0 is the boot block, block 1 the super-block.
  65    SystemV FS: block 0 contains both the boot sector and the super-block. */
  66 /* The first inode zone is sb->sv_firstinodezone (1 or 2). */
  67
  68 /* Among the inodes ... */
  69 /* 0 is non-existent */
  70 #define SYSV_BADBL_INO  1       /* inode of bad blocks file */
  71 #define SYSV_ROOT_INO   2       /* inode of root directory */
  72
  73
  74 /* Xenix super-block data on disk */
  75 #define XENIX_NICINOD   100     /* number of inode cache entries */
  76 #define XENIX_NICFREE   100     /* number of free block list chunk entries */
  77 struct xenix_super_block {
  78         u16             s_isize; /* index of first data zone */
  79         u32             s_fsize __packed2__; /* total number of zones of this fs */
  80         /* the start of the free block list: */
  81         u16             s_nfree;        /* number of free blocks in s_free, <= XENIX_NICFREE */
  82         u32             s_free[XENIX_NICFREE]; /* first free block list chunk */
  83         /* the cache of free inodes: */
  84         u16             s_ninode; /* number of free inodes in s_inode, <= XENIX_NICINOD */
  85         sysv_ino_t      s_inode[XENIX_NICINOD]; /* some free inodes */
  86         /* locks, not used by Linux: */
  87         char            s_flock;        /* lock during free block list manipulation */
  88         char            s_ilock;        /* lock during inode cache manipulation */
  89         char            s_fmod;         /* super-block modified flag */
  90         char            s_ronly;        /* flag whether fs is mounted read-only */
  91         u32             s_time __packed2__; /* time of last super block update */
  92         u32             s_tfree __packed2__; /* total number of free zones */
  93         u16             s_tinode;       /* total number of free inodes */
  94         s16             s_dinfo[4];     /* device information ?? */
  95         char            s_fname[6];     /* file system volume name */
  96         char            s_fpack[6];     /* file system pack name */
  97         char            s_clean;        /* set to 0x46 when filesystem is properly unmounted */
  98         char            s_fill[371];
  99         s32             s_magic;        /* version of file system */
 100         s32             s_type;         /* type of file system: 1 for 512 byte blocks
 101                                                                 2 for 1024 byte blocks
 102                                                                 3 for 2048 byte blocks */
 103
 104 };
 105
 106 /* Xenix free list block on disk */
 107 struct xenix_freelist_chunk {
 108         u16     fl_nfree;       /* number of free blocks in fl_free, <= XENIX_NICFREE] */
 109         u32     fl_free[XENIX_NICFREE] __packed2__;
 110 };
 111
 112 /* SystemV FS comes in two variants:
 113  * sysv2: System V Release 2 (e.g. Microport), structure elements aligned(2).
 114  * sysv4: System V Release 4 (e.g. Consensys), structure elements aligned(4).
 115  */
 116 #define SYSV_NICINOD    100     /* number of inode cache entries */
 117 #define SYSV_NICFREE    50      /* number of free block list chunk entries */
 118
 119 /* SystemV4 super-block data on disk */
 120 struct sysv4_super_block {
 121         u16     s_isize;        /* index of first data zone */
 122         u16     s_pad0;
 123         u32     s_fsize;        /* total number of zones of this fs */
 124         /* the start of the free block list: */
 125         u16     s_nfree;        /* number of free blocks in s_free, <= SYSV_NICFREE */
 126         u16     s_pad1;
 127         u32     s_free[SYSV_NICFREE]; /* first free block list chunk */
 128         /* the cache of free inodes: */
 129         u16     s_ninode;       /* number of free inodes in s_inode, <= SYSV_NICINOD */
 130         u16     s_pad2;
 131         sysv_ino_t     s_inode[SYSV_NICINOD]; /* some free inodes */
 132         /* locks, not used by Linux: */
 133         char    s_flock;        /* lock during free block list manipulation */
 134         char    s_ilock;        /* lock during inode cache manipulation */
 135         char    s_fmod;         /* super-block modified flag */
 136         char    s_ronly;        /* flag whether fs is mounted read-only */
 137         u32     s_time;         /* time of last super block update */
 138         s16     s_dinfo[4];     /* device information ?? */
 139         u32     s_tfree;        /* total number of free zones */
 140         u16     s_tinode;       /* total number of free inodes */
 141         u16     s_pad3;
 142         char    s_fname[6];     /* file system volume name */
 143         char    s_fpack[6];     /* file system pack name */
 144         s32     s_fill[12];
 145         s32     s_state;        /* file system state: 0x7c269d38-s_time means clean */
 146         s32     s_magic;        /* version of file system */
 147         s32     s_type;         /* type of file system: 1 for 512 byte blocks
 148                                                                 2 for 1024 byte blocks */
 149 };
 150
 151 /* SystemV4 free list block on disk */
 152 struct sysv4_freelist_chunk {
 153         u16 fl_nfree;   /* number of free blocks in fl_free, <= SYSV_NICFREE] */
 154         u32  fl_free[SYSV_NICFREE];
 155 };
 156
 157 /* SystemV2 super-block data on disk */
 158 struct sysv2_super_block {
 159         u16     s_isize;                /* index of first data zone */
 160         u32     s_fsize __packed2__;    /* total number of zones of this fs */
 161         /* the start of the free block list: */
 162         u16     s_nfree;                /* number of free blocks in s_free, <= SYSV_NICFREE */
 163         u32     s_free[SYSV_NICFREE];   /* first free block list chunk */
 164         /* the cache of free inodes: */
 165         u16     s_ninode;               /* number of free inodes in s_inode, <= SYSV_NICINOD */
 166         sysv_ino_t     s_inode[SYSV_NICINOD]; /* some free inodes */
 167         /* locks, not used by Linux: */
 168         char    s_flock;                /* lock during free block list manipulation */
 169         char    s_ilock;                /* lock during inode cache manipulation */
 170         char    s_fmod;                 /* super-block modified flag */
 171         char    s_ronly;                /* flag whether fs is mounted read-only */
 172         u32     s_time __packed2__;     /* time of last super block update */
 173         s16     s_dinfo[4];             /* device information ?? */
 174         u32     s_tfree __packed2__;    /* total number of free zones */
 175         u16     s_tinode;               /* total number of free inodes */
 176         char    s_fname[6];             /* file system volume name */
 177         char    s_fpack[6];             /* file system pack name */
 178         s32     s_fill[14];
 179         s32     s_state;                /* file system state: 0xcb096f43 means clean */
 180         s32     s_magic;                /* version of file system */
 181         s32     s_type;                 /* type of file system: 1 for 512 byte blocks
 182                                                                 2 for 1024 byte blocks */
 183 };
 184
 185 /* SystemV2 free list block on disk */
 186 struct sysv2_freelist_chunk {
 187         u16     fl_nfree;       /* number of free blocks in fl_free, <= SYSV_NICFREE] */
 188         u32     fl_free[SYSV_NICFREE] __packed2__;
 189 };
 190
 191 /* Coherent super-block data on disk */
 192 #define COH_NICINOD     100     /* number of inode cache entries */
 193 #define COH_NICFREE     64      /* number of free block list chunk entries */
 194 struct coh_super_block {
 195         u16             s_isize;        /* index of first data zone */
 196         coh_ulong       s_fsize __packed2__; /* total number of zones of this fs */
 197         /* the start of the free block list: */
 198         u16 s_nfree;    /* number of free blocks in s_free, <= COH_NICFREE */
 199         coh_ulong       s_free[COH_NICFREE] __packed2__; /* first free block list chunk */
 200         /* the cache of free inodes: */
 201         u16             s_ninode;       /* number of free inodes in s_inode, <= COH_NICINOD */
 202         sysv_ino_t      s_inode[COH_NICINOD]; /* some free inodes */
 203         /* locks, not used by Linux: */
 204         char            s_flock;        /* lock during free block list manipulation */
 205         char            s_ilock;        /* lock during inode cache manipulation */
 206         char            s_fmod;         /* super-block modified flag */
 207         char            s_ronly;        /* flag whether fs is mounted read-only */
 208         coh_ulong       s_time __packed2__; /* time of last super block update */
 209         coh_ulong       s_tfree __packed2__; /* total number of free zones */
 210         u16             s_tinode;       /* total number of free inodes */
 211         u16             s_interleave_m; /* interleave factor */
 212         u16             s_interleave_n;
 213         char            s_fname[6];     /* file system volume name */
 214         char            s_fpack[6];     /* file system pack name */
 215         u32             s_unique;       /* zero, not used */
 216 };
 217
 218 /* Coherent free list block on disk */
 219 struct coh_freelist_chunk {
 220         u16 fl_nfree;   /* number of free blocks in fl_free, <= COH_NICFREE] */
 221         u32  fl_free[COH_NICFREE] __packed2__;
 222 };
 223
 224
 225 /* SystemV/Coherent inode data on disk */
 226
 227 struct sysv_inode {
 228         u16 i_mode;
 229         u16 i_nlink;
 230         u16 i_uid;
 231         u16 i_gid;
 232         u32 i_size;
 233         union { /* directories, regular files, ... */
 234                 unsigned char i_addb[3*(10+1+1+1)+1]; /* zone numbers: max. 10 data blocks,
 235                                               * then 1 indirection block,
 236                                               * then 1 double indirection block,
 237                                               * then 1 triple indirection block.
 238                                               * Then maybe a "file generation number" ??
 239                                               */
 240                 /* devices */
 241                 dev_t i_rdev;
 242                 /* named pipes on Coherent */
 243                 struct {
 244                         char p_addp[30];
 245                         s16 p_pnc;
 246                         s16 p_prx;
 247                         s16 p_pwx;
 248                 } i_p;
 249         } i_a;
 250         u32 i_atime;    /* time of last access */
 251         u32 i_mtime;    /* time of last modification */
 252         u32 i_ctime;    /* time of creation */
 253 };
 254
 255 /* The admissible values for i_mode are listed in <linux/stat.h> :
 256  * #define S_IFMT  00170000  mask for type
 257  * #define S_IFREG  0100000  type = regular file
 258  * #define S_IFBLK  0060000  type = block device
 259  * #define S_IFDIR  0040000  type = directory
 260  * #define S_IFCHR  0020000  type = character device
 261  * #define S_IFIFO  0010000  type = named pipe
 262  * #define S_ISUID  0004000  set user id
 263  * #define S_ISGID  0002000  set group id
 264  * #define S_ISVTX  0001000  save swapped text even after use
 265  * Additionally for SystemV:
 266  * #define S_IFLNK  0120000  type = symbolic link
 267  * #define S_IFNAM  0050000  type = XENIX special named file ??
 268  * Additionally for Coherent:
 269  * #define S_IFMPB  0070000  type = multiplexed block device ??
 270  * #define S_IFMPC  0030000  type = multiplexed character device ??
 271  *
 272  * Since Coherent doesn't know about symbolic links, we use a kludgey
 273  * implementation of symbolic links: i_mode = COH_KLUDGE_SYMLINK_MODE
 274  * denotes a symbolic link. When a regular file should get this mode by
 275  * accident, it is automatically converted to COH_KLUDGE_NOT_SYMLINK.
 276  * We use S_IFREG because only regular files (and Coherent pipes...) can have
 277  * data blocks with arbitrary contents associated with them, and S_ISVTX
 278  * ("save swapped text after use") because it is unused on both Linux and
 279  * Coherent: Linux does much more intelligent paging, and Coherent hasn't
 280  * virtual memory at all.
 281  * Same trick for Xenix.
 282  */
 283 #define COH_KLUDGE_SYMLINK_MODE (S_IFREG | S_ISVTX)
 284 #define COH_KLUDGE_NOT_SYMLINK  (S_IFREG | S_ISVTX | S_IRUSR) /* force read access */
 285 extern inline mode_t from_coh_imode(unsigned short mode)
 286 {
 287         if (mode == COH_KLUDGE_SYMLINK_MODE)
 288                 return (S_IFLNK | 0777);
 289         else
 290                 return mode;
 291 }
 292 extern inline unsigned short to_coh_imode(mode_t mode)
 293 {
 294         if (S_ISLNK(mode))
 295                 return COH_KLUDGE_SYMLINK_MODE;
 296         else if (mode == COH_KLUDGE_SYMLINK_MODE)
 297                 return COH_KLUDGE_NOT_SYMLINK;
 298         else
 299                 return mode;
 300 }
 301
 302 /* Admissible values for i_nlink: 0.._LINK_MAX */
 303 #define XENIX_LINK_MAX  126     /* ?? */
 304 #define SYSV_LINK_MAX   126     /* 127? 251? */
 305 #define COH_LINK_MAX    10000   /* max number of hard links to an inode */
 306
 307 /* The number of inodes per block is
 308    sb->sv_inodes_per_block = block_size / sizeof(struct sysv_inode) */
 309 /* The number of indirect pointers per block is
 310    sb->sv_ind_per_block = block_size / sizeof(u32) */
 311
 312
 313 /* SystemV/Coherent directory entry on disk */
 314
 315 #define SYSV_NAMELEN    14      /* max size of name in struct sysv_dir_entry */
 316
 317 struct sysv_dir_entry {
 318         sysv_ino_t inode;
 319         char name[SYSV_NAMELEN]; /* up to 14 characters, the rest are zeroes */
 320 };
 321
 322 #define SYSV_DIRSIZE    sizeof(struct sysv_dir_entry)   /* size of every directory entry */
 323
 324
 325 /* Operations */
 326 /* ========== */
 327
 328
 329 /* identify the FS in memory */
 330 #define FSTYPE_XENIX    1
 331 #define FSTYPE_SYSV4    2
 332 #define FSTYPE_SYSV2    3
 333 #define FSTYPE_COH      4
 334
 335 #define SYSV_MAGIC_BASE         0x012FF7B3
 336
 337 #define XENIX_SUPER_MAGIC       (SYSV_MAGIC_BASE+FSTYPE_XENIX)
 338 #define SYSV4_SUPER_MAGIC       (SYSV_MAGIC_BASE+FSTYPE_SYSV4)
 339 #define SYSV2_SUPER_MAGIC       (SYSV_MAGIC_BASE+FSTYPE_SYSV2)
 340 #define COH_SUPER_MAGIC         (SYSV_MAGIC_BASE+FSTYPE_COH)
 341
 342 #ifdef __KERNEL__
 343
 344 /* sv_get_hash_table(sb,dev,block) is equivalent to  get_hash_table(dev,block,block_size)  */
 345 static inline struct buffer_head *
 346 sv_get_hash_table (struct super_block *sb, kdev_t dev, unsigned int block)
 347 {
 348         return get_hash_table (dev, block + sb->sv_block_base, sb->sv_block_size);
 349 }
 350
 351 /* sv_getblk(sb,dev,block) is equivalent to  getblk(dev,block,block_size)  */
 352 static inline struct buffer_head *
 353 sv_getblk (struct super_block *sb, kdev_t dev, unsigned int block)
 354 {
 355         return getblk (dev, block + sb->sv_block_base, sb->sv_block_size);
 356 }
 357
 358 /* sv_bread(sb,dev,block) is equivalent to  bread(dev,block,block_size)  */
 359 static inline struct buffer_head *
 360 sv_bread (struct super_block *sb, kdev_t dev, unsigned int block)
 361 {
 362         return bread (dev, block + sb->sv_block_base, sb->sv_block_size);
 363 }
 364
 365
 366 /*
 367  * Function prototypes
 368  */
 369
 370 extern struct inode * sysv_new_inode(const struct inode * dir);
 371 extern void sysv_free_inode(struct inode * inode);
 372 extern unsigned long sysv_count_free_inodes(struct super_block *sb);
 373 extern int sysv_new_block(struct super_block * sb);
 374 extern void sysv_free_block(struct super_block * sb, unsigned int block);
 375 extern unsigned long sysv_count_free_blocks(struct super_block *sb);
 376
 377 extern struct buffer_head * sysv_file_bread(struct inode *, int, int);
 378
 379 extern void sysv_truncate(struct inode *);
 380 extern void sysv_write_inode(struct inode *, int);
 381 extern int sysv_sync_inode(struct inode *);
 382 extern int sysv_sync_file(struct file *, struct dentry *, int);
 383 extern int sysv_notify_change(struct dentry *, struct iattr *);
 384
 385 extern struct inode_operations sysv_file_inode_operations;
 386 extern struct inode_operations sysv_symlink_inode_operations;
 387 extern struct inode_operations sysv_dir_inode_operations;
 388 extern struct file_operations sysv_file_operations;
 389 extern struct file_operations sysv_dir_operations;
 390 extern struct address_space_operations sysv_aops;
 391
 392 #endif /* __KERNEL__ */
 393
 394 #endif
 395