root/fs/msdos/inode.c

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DEFINITIONS

This source file includes following definitions.
  1. msdos_put_inode
  2. msdos_put_super
  3. parse_options
  4. msdos_read_super
  5. msdos_statfs
  6. msdos_bmap
  7. msdos_read_inode
  8. msdos_write_inode
  9. msdos_notify_change

   1 /*
   2  *  linux/fs/msdos/inode.c
   3  *
   4  *  Written 1992,1993 by Werner Almesberger
   5  */
   6 
   7 #include <linux/msdos_fs.h>
   8 #include <linux/kernel.h>
   9 #include <linux/sched.h>
  10 #include <linux/errno.h>
  11 #include <linux/string.h>
  12 #include <linux/ctype.h>
  13 #include <linux/stat.h>
  14 #include <linux/locks.h>
  15 
  16 #include <asm/segment.h>
  17 
  18 
  19 void msdos_put_inode(struct inode *inode)
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  20 {
  21         struct inode *depend;
  22         struct super_block *sb;
  23 
  24         if (inode->i_nlink) {
  25                 if (MSDOS_I(inode)->i_busy) cache_inval_inode(inode);
  26                 return;
  27         }
  28         inode->i_size = 0;
  29         msdos_truncate(inode);
  30         depend = MSDOS_I(inode)->i_depend;
  31         sb = inode->i_sb;
  32         clear_inode(inode);
  33         if (depend) {
  34                 if (MSDOS_I(depend)->i_old != inode) {
  35                         printk("Invalid link (0x%X): expected 0x%X, got 0x%X\n",
  36                             (int) depend,(int) inode,(int) MSDOS_I(depend)->
  37                             i_old);
  38                         fs_panic(sb,"...");
  39                         return;
  40                 }
  41                 MSDOS_I(depend)->i_old = NULL;
  42                 iput(depend);
  43         }
  44 }
  45 
  46 
  47 void msdos_put_super(struct super_block *sb)
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  48 {
  49         cache_inval_dev(sb->s_dev);
  50         lock_super(sb);
  51         sb->s_dev = 0;
  52         unlock_super(sb);
  53         return;
  54 }
  55 
  56 
  57 static struct super_operations msdos_sops = { 
  58         msdos_read_inode,
  59         msdos_notify_change,
  60         msdos_write_inode,
  61         msdos_put_inode,
  62         msdos_put_super,
  63         NULL, /* added in 0.96c */
  64         msdos_statfs,
  65         NULL
  66 };
  67 
  68 
  69 static int parse_options(char *options,char *check,char *conversion,uid_t *uid,
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  70     gid_t *gid,int *umask,int *debug,int *fat,int *quiet)
  71 {
  72         char *this_char,*value;
  73 
  74         *check = 'n';
  75         *conversion = 'b';
  76         *uid = current->uid;
  77         *gid = current->gid;
  78         *umask = current->umask;
  79         *debug = *fat = *quiet = 0;
  80         if (!options) return 1;
  81         for (this_char = strtok(options,","); this_char; this_char = strtok(NULL,",")) {
  82                 if ((value = strchr(this_char,'=')) != NULL)
  83                         *value++ = 0;
  84                 if (!strcmp(this_char,"check") && value) {
  85                         if (value[0] && !value[1] && strchr("rns",*value))
  86                                 *check = *value;
  87                         else if (!strcmp(value,"relaxed")) *check = 'r';
  88                         else if (!strcmp(value,"normal")) *check = 'n';
  89                         else if (!strcmp(value,"strict")) *check = 's';
  90                         else return 0;
  91                 }
  92                 else if (!strcmp(this_char,"conv") && value) {
  93                         if (value[0] && !value[1] && strchr("bta",*value))
  94                                 *conversion = *value;
  95                         else if (!strcmp(value,"binary")) *conversion = 'b';
  96                         else if (!strcmp(value,"text")) *conversion = 't';
  97                         else if (!strcmp(value,"auto")) *conversion = 'a';
  98                         else return 0;
  99                 }
 100                 else if (!strcmp(this_char,"uid")) {
 101                         if (!value || !*value)
 102                                 return 0;
 103                         *uid = simple_strtoul(value,&value,0);
 104                         if (*value)
 105                                 return 0;
 106                 }
 107                 else if (!strcmp(this_char,"gid")) {
 108                         if (!value || !*value)
 109                                 return 0;
 110                         *gid = simple_strtoul(value,&value,0);
 111                         if (*value)
 112                                 return 0;
 113                 }
 114                 else if (!strcmp(this_char,"umask")) {
 115                         if (!value || !*value)
 116                                 return 0;
 117                         *umask = simple_strtoul(value,&value,8);
 118                         if (*value)
 119                                 return 0;
 120                 }
 121                 else if (!strcmp(this_char,"debug")) {
 122                         if (value) return 0;
 123                         *debug = 1;
 124                 }
 125                 else if (!strcmp(this_char,"fat")) {
 126                         if (!value || !*value)
 127                                 return 0;
 128                         *fat = simple_strtoul(value,&value,0);
 129                         if (*value || (*fat != 12 && *fat != 16))
 130                                 return 0;
 131                 }
 132                 else if (!strcmp(this_char,"quiet")) {
 133                         if (value) return 0;
 134                         *quiet = 1;
 135                 }
 136                 else return 0;
 137         }
 138         return 1;
 139 }
 140 
 141 
 142 /* Read the super block of an MS-DOS FS. */
 143 
 144 struct super_block *msdos_read_super(struct super_block *s,void *data,
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 145                                      int silent)
 146 {
 147         struct buffer_head *bh;
 148         struct msdos_boot_sector *b;
 149         int data_sectors,logical_sector_size,sector_mult;
 150         int debug,error,fat,quiet;
 151         char check,conversion;
 152         uid_t uid;
 153         gid_t gid;
 154         int umask;
 155 
 156         if (!parse_options((char *) data,&check,&conversion,&uid,&gid,&umask,
 157             &debug,&fat,&quiet)) {
 158                 s->s_dev = 0;
 159                 return NULL;
 160         }
 161         cache_init();
 162         lock_super(s);
 163         bh = bread(s->s_dev, 0, BLOCK_SIZE);
 164         unlock_super(s);
 165         if (bh == NULL) {
 166                 s->s_dev = 0;
 167                 printk("MSDOS bread failed\n");
 168                 return NULL;
 169         }
 170         b = (struct msdos_boot_sector *) bh->b_data;
 171         s->s_blocksize = 1024;  /* we cannot handle anything else yet */
 172         s->s_blocksize_bits = 10;       /* we cannot handle anything else yet */
 173 
 174 /*
 175  * The DOS3 partition size limit is *not* 32M as many people think.  
 176  * Instead, it is 64K sectors (with the usual sector size being
 177  * 512 bytes, leading to a 32M limit).
 178  * 
 179  * DOS 3 partition managers got around this problem by faking a 
 180  * larger sector size, ie treating multiple physical sectors as 
 181  * a single logical sector.
 182  * 
 183  * We can accommodate this scheme by adjusting our cluster size,
 184  * fat_start, and data_start by an appropriate value.
 185  *
 186  * (by Drew Eckhardt)
 187  */
 188 
 189 #define ROUND_TO_MULTIPLE(n,m) ((n) && (m) ? (n)+(m)-1-((n)-1)%(m) : 0)
 190     /* don't divide by zero */
 191 
 192         logical_sector_size = CF_LE_W(*(unsigned short *) &b->sector_size);
 193         sector_mult = logical_sector_size >> SECTOR_BITS;
 194         MSDOS_SB(s)->cluster_size = b->cluster_size*sector_mult;
 195         MSDOS_SB(s)->fats = b->fats;
 196         MSDOS_SB(s)->fat_start = CF_LE_W(b->reserved)*sector_mult;
 197         MSDOS_SB(s)->fat_length = CF_LE_W(b->fat_length)*sector_mult;
 198         MSDOS_SB(s)->dir_start = (CF_LE_W(b->reserved)+b->fats*CF_LE_W(
 199             b->fat_length))*sector_mult;
 200         MSDOS_SB(s)->dir_entries = CF_LE_W(*((unsigned short *) &b->dir_entries
 201             ));
 202         MSDOS_SB(s)->data_start = MSDOS_SB(s)->dir_start+ROUND_TO_MULTIPLE((
 203             MSDOS_SB(s)->dir_entries << MSDOS_DIR_BITS) >> SECTOR_BITS,
 204             sector_mult);
 205         data_sectors = (CF_LE_W(*((unsigned short *) &b->sectors)) ?
 206             CF_LE_W(*((unsigned short *) &b->sectors)) :
 207             CF_LE_L(b->total_sect))*sector_mult-MSDOS_SB(s)->data_start;
 208         error = !b->cluster_size || !sector_mult;
 209         if (!error) {
 210                 MSDOS_SB(s)->clusters = b->cluster_size ? data_sectors/
 211                     b->cluster_size/sector_mult : 0;
 212                 MSDOS_SB(s)->fat_bits = fat ? fat : MSDOS_SB(s)->clusters >
 213                     MSDOS_FAT12 ? 16 : 12;
 214                 error = !MSDOS_SB(s)->fats || (MSDOS_SB(s)->dir_entries &
 215                     (MSDOS_DPS-1)) || MSDOS_SB(s)->clusters+2 > MSDOS_SB(s)->
 216                     fat_length*SECTOR_SIZE*8/MSDOS_SB(s)->fat_bits ||
 217                     (logical_sector_size & (SECTOR_SIZE-1)) || !b->secs_track ||
 218                     !b->heads;
 219         }
 220         brelse(bh);
 221         if (error || debug) {
 222                 printk("[MS-DOS FS Rel. 12,FAT %d,check=%c,conv=%c,"
 223                     "uid=%d,gid=%d,umask=%03o%s]\n",MSDOS_SB(s)->fat_bits,check,
 224                     conversion,uid,gid,umask,MSDOS_CAN_BMAP(MSDOS_SB(s)) ?
 225                     ",bmap" : "");
 226                 printk("[me=0x%x,cs=%d,#f=%d,fs=%d,fl=%d,ds=%d,de=%d,data=%d,"
 227                     "se=%d,ts=%ld,ls=%d]\n",b->media,MSDOS_SB(s)->cluster_size,
 228                     MSDOS_SB(s)->fats,MSDOS_SB(s)->fat_start,MSDOS_SB(s)->
 229                     fat_length,MSDOS_SB(s)->dir_start,MSDOS_SB(s)->dir_entries,
 230                     MSDOS_SB(s)->data_start,CF_LE_W(*(unsigned short *) &b->
 231                     sectors),b->total_sect,logical_sector_size);
 232         }
 233         if (error) {
 234                 if (!silent)
 235                         printk("VFS: Can't find a valid MSDOS filesystem on dev 0x%04x.\n",
 236                                    s->s_dev);
 237                 s->s_dev = 0;
 238                 return NULL;
 239         }
 240         s->s_magic = MSDOS_SUPER_MAGIC;
 241         MSDOS_SB(s)->name_check = check;
 242         MSDOS_SB(s)->conversion = conversion;
 243         /* set up enough so that it can read an inode */
 244         s->s_op = &msdos_sops;
 245         MSDOS_SB(s)->fs_uid = uid;
 246         MSDOS_SB(s)->fs_gid = gid;
 247         MSDOS_SB(s)->fs_umask = umask;
 248         MSDOS_SB(s)->quiet = quiet;
 249         MSDOS_SB(s)->free_clusters = -1; /* don't know yet */
 250         MSDOS_SB(s)->fat_wait = NULL;
 251         MSDOS_SB(s)->fat_lock = 0;
 252         MSDOS_SB(s)->prev_free = 0;
 253         if (!(s->s_mounted = iget(s,MSDOS_ROOT_INO))) {
 254                 s->s_dev = 0;
 255                 printk("get root inode failed\n");
 256                 return NULL;
 257         }
 258         return s;
 259 }
 260 
 261 
 262 void msdos_statfs(struct super_block *sb,struct statfs *buf)
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 263 {
 264         int free,nr;
 265 
 266         put_fs_long(sb->s_magic,&buf->f_type);
 267         put_fs_long(MSDOS_SB(sb)->cluster_size*SECTOR_SIZE,&buf->f_bsize);
 268         put_fs_long(MSDOS_SB(sb)->clusters,&buf->f_blocks);
 269         lock_fat(sb);
 270         if (MSDOS_SB(sb)->free_clusters != -1)
 271                 free = MSDOS_SB(sb)->free_clusters;
 272         else {
 273                 free = 0;
 274                 for (nr = 2; nr < MSDOS_SB(sb)->clusters+2; nr++)
 275                         if (!fat_access(sb,nr,-1)) free++;
 276                 MSDOS_SB(sb)->free_clusters = free;
 277         }
 278         unlock_fat(sb);
 279         put_fs_long(free,&buf->f_bfree);
 280         put_fs_long(free,&buf->f_bavail);
 281         put_fs_long(0,&buf->f_files);
 282         put_fs_long(0,&buf->f_ffree);
 283         put_fs_long(12,&buf->f_namelen);
 284 }
 285 
 286 
 287 int msdos_bmap(struct inode *inode,int block)
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 288 {
 289         struct msdos_sb_info *sb;
 290         int cluster,offset;
 291 
 292         sb = MSDOS_SB(inode->i_sb);
 293         if ((sb->cluster_size & 1) || (sb->data_start & 1)) return 0;
 294         if (inode->i_ino == MSDOS_ROOT_INO) {
 295                 if (sb->dir_start & 1) return 0;
 296                 return (sb->dir_start >> 1)+block;
 297         }
 298         cluster = (block*2)/sb->cluster_size;
 299         offset = (block*2) % sb->cluster_size;
 300         if (!(cluster = get_cluster(inode,cluster))) return 0;
 301         return ((cluster-2)*sb->cluster_size+sb->data_start+offset) >> 1;
 302 }
 303 
 304 
 305 void msdos_read_inode(struct inode *inode)
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 306 {
 307         struct buffer_head *bh;
 308         struct msdos_dir_entry *raw_entry;
 309         int nr;
 310 
 311 /* printk("read inode %d\n",inode->i_ino); */
 312         MSDOS_I(inode)->i_busy = 0;
 313         MSDOS_I(inode)->i_depend = MSDOS_I(inode)->i_old = NULL;
 314         MSDOS_I(inode)->i_binary = 1;
 315         inode->i_uid = MSDOS_SB(inode->i_sb)->fs_uid;
 316         inode->i_gid = MSDOS_SB(inode->i_sb)->fs_gid;
 317         if (inode->i_ino == MSDOS_ROOT_INO) {
 318                 inode->i_mode = (S_IRWXUGO & ~MSDOS_SB(inode->i_sb)->fs_umask) |
 319                     S_IFDIR;
 320                 inode->i_op = &msdos_dir_inode_operations;
 321                 inode->i_nlink = msdos_subdirs(inode)+2;
 322                     /* subdirs (neither . nor ..) plus . and "self" */
 323                 inode->i_size = MSDOS_SB(inode->i_sb)->dir_entries*
 324                     sizeof(struct msdos_dir_entry);
 325                 inode->i_blksize = MSDOS_SB(inode->i_sb)->cluster_size*
 326                     SECTOR_SIZE;
 327                 inode->i_blocks = (inode->i_size+inode->i_blksize-1)/
 328                     inode->i_blksize*MSDOS_SB(inode->i_sb)->cluster_size;
 329                 MSDOS_I(inode)->i_start = 0;
 330                 MSDOS_I(inode)->i_attrs = 0;
 331                 inode->i_mtime = inode->i_atime = inode->i_ctime = 0;
 332                 return;
 333         }
 334         if (!(bh = bread(inode->i_dev,inode->i_ino >> MSDOS_DPB_BITS,
 335             BLOCK_SIZE))) {
 336                 printk("dev = 0x%04X, ino = %ld\n",inode->i_dev,inode->i_ino);
 337                 panic("msdos_read_inode: unable to read i-node block");
 338         }
 339         raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
 340             [inode->i_ino & (MSDOS_DPB-1)];
 341         if ((raw_entry->attr & ATTR_DIR) && !IS_FREE(raw_entry->name)) {
 342                 inode->i_mode = MSDOS_MKMODE(raw_entry->attr,S_IRWXUGO &
 343                     ~MSDOS_SB(inode->i_sb)->fs_umask) | S_IFDIR;
 344                 inode->i_op = &msdos_dir_inode_operations;
 345                 MSDOS_I(inode)->i_start = CF_LE_W(raw_entry->start);
 346                 inode->i_nlink = msdos_subdirs(inode);
 347                     /* includes .., compensating for "self" */
 348 #ifdef DEBUG
 349                 if (!inode->i_nlink) {
 350                         printk("directory %d: i_nlink == 0\n",inode->i_ino);
 351                         inode->i_nlink = 1;
 352                 }
 353 #endif
 354                 inode->i_size = 0;
 355                 if ((nr = CF_LE_W(raw_entry->start)) != 0)
 356                         while (nr != -1) {
 357                                 inode->i_size += SECTOR_SIZE*MSDOS_SB(inode->
 358                                     i_sb)->cluster_size;
 359                                 if (!(nr = fat_access(inode->i_sb,nr,-1))) {
 360                                         printk("Directory %ld: bad FAT\n",
 361                                             inode->i_ino);
 362                                         break;
 363                                 }
 364                         }
 365         }
 366         else {
 367                 inode->i_mode = MSDOS_MKMODE(raw_entry->attr,(IS_NOEXEC(inode)
 368                     ? S_IRUGO|S_IWUGO : S_IRWXUGO) & ~MSDOS_SB(inode->i_sb)->fs_umask) |
 369                     S_IFREG;
 370                 inode->i_op = MSDOS_CAN_BMAP(MSDOS_SB(inode->i_sb)) ? 
 371                     &msdos_file_inode_operations :
 372                     &msdos_file_inode_operations_no_bmap;
 373                 MSDOS_I(inode)->i_start = CF_LE_W(raw_entry->start);
 374                 inode->i_nlink = 1;
 375                 inode->i_size = CF_LE_L(raw_entry->size);
 376         }
 377         MSDOS_I(inode)->i_binary = is_binary(MSDOS_SB(inode->i_sb)->conversion,
 378             raw_entry->ext);
 379         MSDOS_I(inode)->i_attrs = raw_entry->attr & ATTR_UNUSED;
 380         /* this is as close to the truth as we can get ... */
 381         inode->i_blksize = MSDOS_SB(inode->i_sb)->cluster_size*SECTOR_SIZE;
 382         inode->i_blocks = (inode->i_size+inode->i_blksize-1)/
 383             inode->i_blksize*MSDOS_SB(inode->i_sb)->cluster_size;
 384         inode->i_mtime = inode->i_atime = inode->i_ctime =
 385             date_dos2unix(CF_LE_W(raw_entry->time),CF_LE_W(raw_entry->date));
 386         brelse(bh);
 387 }
 388 
 389 
 390 void msdos_write_inode(struct inode *inode)
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 391 {
 392         struct buffer_head *bh;
 393         struct msdos_dir_entry *raw_entry;
 394 
 395         inode->i_dirt = 0;
 396         if (inode->i_ino == MSDOS_ROOT_INO || !inode->i_nlink) return;
 397         if (!(bh = bread(inode->i_dev,inode->i_ino >> MSDOS_DPB_BITS,
 398             BLOCK_SIZE))) {
 399                 printk("dev = 0x%04X, ino = %ld\n",inode->i_dev,inode->i_ino);
 400                 panic("msdos_write_inode: unable to read i-node block");
 401         }
 402         raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
 403             [inode->i_ino & (MSDOS_DPB-1)];
 404         if (S_ISDIR(inode->i_mode)) {
 405                 raw_entry->attr = ATTR_DIR;
 406                 raw_entry->size = 0;
 407         }
 408         else {
 409                 raw_entry->attr = ATTR_NONE;
 410                 raw_entry->size = CT_LE_L(inode->i_size);
 411         }
 412         raw_entry->attr |= MSDOS_MKATTR(inode->i_mode) |
 413             MSDOS_I(inode)->i_attrs;
 414         raw_entry->start = CT_LE_L(MSDOS_I(inode)->i_start);
 415         date_unix2dos(inode->i_mtime,&raw_entry->time,&raw_entry->date);
 416         raw_entry->time = CT_LE_W(raw_entry->time);
 417         raw_entry->date = CT_LE_W(raw_entry->date);
 418         mark_buffer_dirty(bh, 1);
 419         brelse(bh);
 420 }
 421 
 422 
 423 int msdos_notify_change(int flags,struct inode *inode)
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 424 {
 425         int error;
 426 
 427         error = 0;
 428         if ((flags & NOTIFY_UIDGID) && (inode->i_uid != MSDOS_SB(inode->i_sb)->
 429             fs_uid || inode->i_gid != MSDOS_SB(inode->i_sb)->fs_gid)) {
 430                 inode->i_uid = MSDOS_SB(inode->i_sb)->fs_uid;
 431                 inode->i_gid = MSDOS_SB(inode->i_sb)->fs_gid;
 432                 error = -EPERM;
 433         }
 434         if (!(flags & NOTIFY_MODE))
 435                 return MSDOS_SB(inode->i_sb)->quiet ? 0 : error;
 436         if (inode->i_mode & ~MSDOS_VALID_MODE) {
 437                 inode->i_mode &= MSDOS_VALID_MODE;
 438                 error = -EPERM;
 439         }
 440         if (IS_NOEXEC(inode) && !S_ISDIR(inode->i_mode))
 441                 inode->i_mode &= S_IFMT | S_IRUGO | S_IWUGO;
 442         else inode->i_mode |= S_IXUGO;
 443         inode->i_mode = ((inode->i_mode & S_IFMT) | ((((inode->i_mode & S_IRWXU
 444             & ~MSDOS_SB(inode->i_sb)->fs_umask) | S_IRUSR) >> 6)*S_IXUGO)) &
 445             ~MSDOS_SB(inode->i_sb)->fs_umask;
 446         return MSDOS_SB(inode->i_sb)->quiet ? 0 : error;
 447 }

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