fs/msdos/inode.c

/* */
This source file includes following definitions.
msdos_put_inode
msdos_put_super
parse_options
msdos_read_super
msdos_statfs
msdos_bmap
msdos_read_inode
msdos_write_inode
msdos_notify_change
init_module
cleanup_module
   1 /*
   2  *  linux/fs/msdos/inode.c
   3  *
   4  *  Written 1992,1993 by Werner Almesberger
   5  */
   6 
   7 #ifdef MODULE
   8 #include <linux/module.h>
   9 #include <linux/version.h>
  10 #else
  11 #define MOD_INC_USE_COUNT
  12 #define MOD_DEC_USE_COUNT
  13 #endif
  14 
  15 #include <linux/msdos_fs.h>
  16 #include <linux/kernel.h>
  17 #include <linux/sched.h>
  18 #include <linux/errno.h>
  19 #include <linux/string.h>
  20 #include <linux/ctype.h>
  21 #include <linux/major.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/fs.h>
  24 #include <linux/stat.h>
  25 #include <linux/locks.h>
  26 
  27 #include "msbuffer.h"
  28 
  29 #include <asm/segment.h>
  30 
  31 void msdos_put_inode(struct inode *inode)
     /*  */
  32 {
  33         struct inode *depend;
  34         struct super_block *sb;
  35 
  36         if (inode->i_nlink) {
  37                 if (MSDOS_I(inode)->i_busy) cache_inval_inode(inode);
  38                 return;
  39         }
  40         inode->i_size = 0;
  41         msdos_truncate(inode);
  42         depend = MSDOS_I(inode)->i_depend;
  43         sb = inode->i_sb;
  44         clear_inode(inode);
  45         if (depend) {
  46                 if (MSDOS_I(depend)->i_old != inode) {
  47                         printk("Invalid link (0x%p): expected 0x%p, got 0x%p\n",
  48                             depend, inode, MSDOS_I(depend)->i_old);
  49                         fs_panic(sb,"...");
  50                         return;
  51                 }
  52                 MSDOS_I(depend)->i_old = NULL;
  53                 iput(depend);
  54         }
  55 }
  56 
  57 
  58 void msdos_put_super(struct super_block *sb)
     /*  */
  59 {
  60         cache_inval_dev(sb->s_dev);
  61         set_blocksize (sb->s_dev,BLOCK_SIZE);
  62         lock_super(sb);
  63         sb->s_dev = 0;
  64         unlock_super(sb);
  65         MOD_DEC_USE_COUNT;
  66         return;
  67 }
  68 
  69 
  70 static struct super_operations msdos_sops = { 
  71         msdos_read_inode,
  72         msdos_notify_change,
  73         msdos_write_inode,
  74         msdos_put_inode,
  75         msdos_put_super,
  76         NULL, /* added in 0.96c */
  77         msdos_statfs,
  78         NULL
  79 };
  80 
  81 
  82 static int parse_options(char *options,char *check,char *conversion,uid_t *uid,
     /*  */
  83     gid_t *gid,int *umask,int *debug,int *fat,int *quiet,
  84         int *blksize)
  85 {
  86         char *this_char,*value;
  87 
  88         *check = 'n';
  89         *conversion = 'b';
  90         *uid = current->uid;
  91         *gid = current->gid;
  92         *umask = current->fs->umask;
  93         *debug = *fat = *quiet = 0;
  94         if (!options) return 1;
  95         for (this_char = strtok(options,","); this_char; this_char = strtok(NULL,",")) {
  96                 if ((value = strchr(this_char,'=')) != NULL)
  97                         *value++ = 0;
  98                 if (!strcmp(this_char,"check") && value) {
  99                         if (value[0] && !value[1] && strchr("rns",*value))
 100                                 *check = *value;
 101                         else if (!strcmp(value,"relaxed")) *check = 'r';
 102                         else if (!strcmp(value,"normal")) *check = 'n';
 103                         else if (!strcmp(value,"strict")) *check = 's';
 104                         else return 0;
 105                 }
 106                 else if (!strcmp(this_char,"conv") && value) {
 107                         if (value[0] && !value[1] && strchr("bta",*value))
 108                                 *conversion = *value;
 109                         else if (!strcmp(value,"binary")) *conversion = 'b';
 110                         else if (!strcmp(value,"text")) *conversion = 't';
 111                         else if (!strcmp(value,"auto")) *conversion = 'a';
 112                         else return 0;
 113                 }
 114                 else if (!strcmp(this_char,"uid")) {
 115                         if (!value || !*value)
 116                                 return 0;
 117                         *uid = simple_strtoul(value,&value,0);
 118                         if (*value)
 119                                 return 0;
 120                 }
 121                 else if (!strcmp(this_char,"gid")) {
 122                         if (!value || !*value)
 123                                 return 0;
 124                         *gid = simple_strtoul(value,&value,0);
 125                         if (*value)
 126                                 return 0;
 127                 }
 128                 else if (!strcmp(this_char,"umask")) {
 129                         if (!value || !*value)
 130                                 return 0;
 131                         *umask = simple_strtoul(value,&value,8);
 132                         if (*value)
 133                                 return 0;
 134                 }
 135                 else if (!strcmp(this_char,"debug")) {
 136                         if (value) return 0;
 137                         *debug = 1;
 138                 }
 139                 else if (!strcmp(this_char,"fat")) {
 140                         if (!value || !*value)
 141                                 return 0;
 142                         *fat = simple_strtoul(value,&value,0);
 143                         if (*value || (*fat != 12 && *fat != 16))
 144                                 return 0;
 145                 }
 146                 else if (!strcmp(this_char,"quiet")) {
 147                         if (value) return 0;
 148                         *quiet = 1;
 149                 }
 150                 else if (!strcmp(this_char,"blocksize")) {
 151                         *blksize = simple_strtoul(value,&value,0);
 152                         if (*value)
 153                                 return 0;
 154                         if (*blksize != 512 && *blksize != 1024){
 155                                 printk ("MSDOS FS: Invalid blocksize (512 or 1024)\n");
 156                         }
 157                 }
 158                 else return 0;
 159         }
 160         return 1;
 161 }
 162 
 163 
 164 /* Read the super block of an MS-DOS FS. */
 165 
 166 struct super_block *msdos_read_super(struct super_block *sb,void *data,
     /*  */
 167                                      int silent)
 168 {
 169         struct buffer_head *bh;
 170         struct msdos_boot_sector *b;
 171         int data_sectors,logical_sector_size,sector_mult;
 172         int debug,error,fat,quiet;
 173         char check,conversion;
 174         uid_t uid;
 175         gid_t gid;
 176         int umask;
 177         int blksize = 512;
 178 
 179         MOD_INC_USE_COUNT;
 180         if (hardsect_size[MAJOR(sb->s_dev)] != NULL){
 181                 blksize = hardsect_size[MAJOR(sb->s_dev)][MINOR(sb->s_dev)];
 182                 if (blksize != 512){
 183                         printk ("MSDOS: Hardware sector size is %d\n",blksize);
 184                 }
 185         }
 186         if (!parse_options((char *) data,&check,&conversion,&uid,&gid,&umask,
 187             &debug,&fat,&quiet,&blksize)
 188                 || (blksize != 512 && blksize != 1024)) {
 189                 sb->s_dev = 0;
 190                 MOD_DEC_USE_COUNT;
 191                 return NULL;
 192         }
 193         cache_init();
 194         lock_super(sb);
 195         /* The first read is always 1024 bytes */
 196         sb->s_blocksize = 1024;
 197         set_blocksize(sb->s_dev, 1024);
 198         bh = bread(sb->s_dev, 0, 1024);
 199         unlock_super(sb);
 200         if (bh == NULL || !msdos_is_uptodate(sb,bh)) {
 201                 brelse (bh);
 202                 sb->s_dev = 0;
 203                 printk("MSDOS bread failed\n");
 204                 MOD_DEC_USE_COUNT;
 205                 return NULL;
 206         }
 207         b = (struct msdos_boot_sector *) bh->b_data;
 208         set_blocksize(sb->s_dev, blksize);
 209 /*
 210  * The DOS3 partition size limit is *not* 32M as many people think.  
 211  * Instead, it is 64K sectors (with the usual sector size being
 212  * 512 bytes, leading to a 32M limit).
 213  * 
 214  * DOS 3 partition managers got around this problem by faking a 
 215  * larger sector size, ie treating multiple physical sectors as 
 216  * a single logical sector.
 217  * 
 218  * We can accommodate this scheme by adjusting our cluster size,
 219  * fat_start, and data_start by an appropriate value.
 220  *
 221  * (by Drew Eckhardt)
 222  */
 223 
 224 #define ROUND_TO_MULTIPLE(n,m) ((n) && (m) ? (n)+(m)-1-((n)-1)%(m) : 0)
 225     /* don't divide by zero */
 226 
 227         logical_sector_size = CF_LE_W(*(unsigned short *) &b->sector_size);
 228         sector_mult = logical_sector_size >> SECTOR_BITS;
 229         MSDOS_SB(sb)->cluster_size = b->cluster_size*sector_mult;
 230         MSDOS_SB(sb)->fats = b->fats;
 231         MSDOS_SB(sb)->fat_start = CF_LE_W(b->reserved)*sector_mult;
 232         MSDOS_SB(sb)->fat_length = CF_LE_W(b->fat_length)*sector_mult;
 233         MSDOS_SB(sb)->dir_start = (CF_LE_W(b->reserved)+b->fats*CF_LE_W(
 234             b->fat_length))*sector_mult;
 235         MSDOS_SB(sb)->dir_entries = CF_LE_W(*((unsigned short *) &b->dir_entries
 236             ));
 237         MSDOS_SB(sb)->data_start = MSDOS_SB(sb)->dir_start+ROUND_TO_MULTIPLE((
 238             MSDOS_SB(sb)->dir_entries << MSDOS_DIR_BITS) >> SECTOR_BITS,
 239             sector_mult);
 240         data_sectors = (CF_LE_W(*((unsigned short *) &b->sectors)) ?
 241             CF_LE_W(*((unsigned short *) &b->sectors)) :
 242             CF_LE_L(b->total_sect))*sector_mult-MSDOS_SB(sb)->data_start;
 243         error = !b->cluster_size || !sector_mult;
 244         if (!error) {
 245                 MSDOS_SB(sb)->clusters = b->cluster_size ? data_sectors/
 246                     b->cluster_size/sector_mult : 0;
 247                 MSDOS_SB(sb)->fat_bits = fat ? fat : MSDOS_SB(sb)->clusters >
 248                     MSDOS_FAT12 ? 16 : 12;
 249                 error = !MSDOS_SB(sb)->fats || (MSDOS_SB(sb)->dir_entries &
 250                     (MSDOS_DPS-1)) || MSDOS_SB(sb)->clusters+2 > MSDOS_SB(sb)->
 251                     fat_length*SECTOR_SIZE*8/MSDOS_SB(sb)->fat_bits ||
 252                     (logical_sector_size & (SECTOR_SIZE-1)) || !b->secs_track ||
 253                     !b->heads;
 254         }
 255         brelse(bh);
 256         /*
 257                 This must be done after the brelse because the bh is a dummy
 258                 allocated by msdos_bread (see buffer.c)
 259         */
 260         sb->s_blocksize = blksize;      /* Using this small block size solve the */
 261                                 /* the misfit with buffer cache and cluster */
 262                                 /* because cluster (DOS) are often aligned */
 263                                 /* on odd sector */
 264         sb->s_blocksize_bits = blksize == 512 ? 9 : 10;
 265         if (error || debug) {
 266                 /* The MSDOS_CAN_BMAP is obsolete, but left just to remember */
 267                 printk("[MS-DOS FS Rel. 12,FAT %d,check=%c,conv=%c,"
 268                     "uid=%d,gid=%d,umask=%03o%s]\n",MSDOS_SB(sb)->fat_bits,check,
 269                     conversion,uid,gid,umask,MSDOS_CAN_BMAP(MSDOS_SB(sb)) ?
 270                     ",bmap" : "");
 271                 printk("[me=0x%x,cs=%d,#f=%d,fs=%d,fl=%d,ds=%d,de=%d,data=%d,"
 272                     "se=%d,ts=%ld,ls=%d]\n",b->media,MSDOS_SB(sb)->cluster_size,
 273                     MSDOS_SB(sb)->fats,MSDOS_SB(sb)->fat_start,MSDOS_SB(sb)->
 274                     fat_length,MSDOS_SB(sb)->dir_start,MSDOS_SB(sb)->dir_entries,
 275                     MSDOS_SB(sb)->data_start,CF_LE_W(*(unsigned short *) &b->
 276                     sectors),(unsigned long)b->total_sect,logical_sector_size);
 277                 printk ("Transaction block size = %d\n",blksize);
 278         }
 279         if (error) {
 280                 if (!silent)
 281                         printk("VFS: Can't find a valid MSDOS filesystem on dev 0x%04x.\n",
 282                                    sb->s_dev);
 283                 sb->s_dev = 0;
 284                 MOD_DEC_USE_COUNT;
 285                 return NULL;
 286         }
 287         sb->s_magic = MSDOS_SUPER_MAGIC;
 288         MSDOS_SB(sb)->name_check = check;
 289         MSDOS_SB(sb)->conversion = conversion;
 290         /* set up enough so that it can read an inode */
 291         sb->s_op = &msdos_sops;
 292         MSDOS_SB(sb)->fs_uid = uid;
 293         MSDOS_SB(sb)->fs_gid = gid;
 294         MSDOS_SB(sb)->fs_umask = umask;
 295         MSDOS_SB(sb)->quiet = quiet;
 296         MSDOS_SB(sb)->free_clusters = -1; /* don't know yet */
 297         MSDOS_SB(sb)->fat_wait = NULL;
 298         MSDOS_SB(sb)->fat_lock = 0;
 299         MSDOS_SB(sb)->prev_free = 0;
 300         if (!(sb->s_mounted = iget(sb,MSDOS_ROOT_INO))) {
 301                 sb->s_dev = 0;
 302                 printk("get root inode failed\n");
 303                 MOD_DEC_USE_COUNT;
 304                 return NULL;
 305         }
 306         return sb;
 307 }
 308 
 309 
 310 void msdos_statfs(struct super_block *sb,struct statfs *buf, int bufsiz)
     /*  */
 311 {
 312         int free,nr;
 313         struct statfs tmp;
 314 
 315         lock_fat(sb);
 316         if (MSDOS_SB(sb)->free_clusters != -1)
 317                 free = MSDOS_SB(sb)->free_clusters;
 318         else {
 319                 free = 0;
 320                 for (nr = 2; nr < MSDOS_SB(sb)->clusters+2; nr++)
 321                         if (!fat_access(sb,nr,-1)) free++;
 322                 MSDOS_SB(sb)->free_clusters = free;
 323         }
 324         unlock_fat(sb);
 325         tmp.f_type = sb->s_magic;
 326         tmp.f_bsize = MSDOS_SB(sb)->cluster_size*SECTOR_SIZE;
 327         tmp.f_blocks = MSDOS_SB(sb)->clusters;
 328         tmp.f_bfree = free;
 329         tmp.f_bavail = free;
 330         tmp.f_files = 0;
 331         tmp.f_ffree = 0;
 332         tmp.f_namelen = 12;
 333         memcpy_tofs(buf, &tmp, bufsiz);
 334 }
 335 
 336 
 337 int msdos_bmap(struct inode *inode,int block)
     /*  */
 338 {
 339         struct msdos_sb_info *sb;
 340         int cluster,offset;
 341 
 342         sb = MSDOS_SB(inode->i_sb);
 343         if (inode->i_ino == MSDOS_ROOT_INO) {
 344                 return sb->dir_start + block;
 345         }
 346         cluster = block/sb->cluster_size;
 347         offset = block % sb->cluster_size;
 348         if (!(cluster = get_cluster(inode,cluster))) return 0;
 349         return (cluster-2)*sb->cluster_size+sb->data_start+offset;
 350 }
 351 
 352 
 353 void msdos_read_inode(struct inode *inode)
     /*  */
 354 {
 355         struct super_block *sb = inode->i_sb;
 356         struct buffer_head *bh;
 357         struct msdos_dir_entry *raw_entry;
 358         int nr;
 359 
 360 /* printk("read inode %d\n",inode->i_ino); */
 361         MSDOS_I(inode)->i_busy = 0;
 362         MSDOS_I(inode)->i_depend = MSDOS_I(inode)->i_old = NULL;
 363         MSDOS_I(inode)->i_binary = 1;
 364         inode->i_uid = MSDOS_SB(inode->i_sb)->fs_uid;
 365         inode->i_gid = MSDOS_SB(inode->i_sb)->fs_gid;
 366         if (inode->i_ino == MSDOS_ROOT_INO) {
 367                 inode->i_mode = (S_IRWXUGO & ~MSDOS_SB(inode->i_sb)->fs_umask) |
 368                     S_IFDIR;
 369                 inode->i_op = &msdos_dir_inode_operations;
 370                 inode->i_nlink = msdos_subdirs(inode)+2;
 371                     /* subdirs (neither . nor ..) plus . and "self" */
 372                 inode->i_size = MSDOS_SB(inode->i_sb)->dir_entries*
 373                     sizeof(struct msdos_dir_entry);
 374                 inode->i_blksize = MSDOS_SB(inode->i_sb)->cluster_size*
 375                     SECTOR_SIZE;
 376                 inode->i_blocks = (inode->i_size+inode->i_blksize-1)/
 377                     inode->i_blksize*MSDOS_SB(inode->i_sb)->cluster_size;
 378                 MSDOS_I(inode)->i_start = 0;
 379                 MSDOS_I(inode)->i_attrs = 0;
 380                 inode->i_mtime = inode->i_atime = inode->i_ctime = 0;
 381                 return;
 382         }
 383         if (!(bh = bread(inode->i_dev,inode->i_ino >> MSDOS_DPB_BITS,
 384             SECTOR_SIZE))) {
 385                 printk("dev = 0x%04X, ino = %ld\n",inode->i_dev,inode->i_ino);
 386                 panic("msdos_read_inode: unable to read i-node block");
 387         }
 388         raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
 389             [inode->i_ino & (MSDOS_DPB-1)];
 390         if ((raw_entry->attr & ATTR_DIR) && !IS_FREE(raw_entry->name)) {
 391                 inode->i_mode = MSDOS_MKMODE(raw_entry->attr,S_IRWXUGO &
 392                     ~MSDOS_SB(inode->i_sb)->fs_umask) | S_IFDIR;
 393                 inode->i_op = &msdos_dir_inode_operations;
 394                 MSDOS_I(inode)->i_start = CF_LE_W(raw_entry->start);
 395                 inode->i_nlink = msdos_subdirs(inode);
 396                     /* includes .., compensating for "self" */
 397 #ifdef DEBUG
 398                 if (!inode->i_nlink) {
 399                         printk("directory %d: i_nlink == 0\n",inode->i_ino);
 400                         inode->i_nlink = 1;
 401                 }
 402 #endif
 403                 inode->i_size = 0;
 404                 if ((nr = CF_LE_W(raw_entry->start)) != 0)
 405                         while (nr != -1) {
 406                                 inode->i_size += SECTOR_SIZE*MSDOS_SB(inode->
 407                                     i_sb)->cluster_size;
 408                                 if (!(nr = fat_access(inode->i_sb,nr,-1))) {
 409                                         printk("Directory %ld: bad FAT\n",
 410                                             inode->i_ino);
 411                                         break;
 412                                 }
 413                         }
 414         }
 415         else {
 416                 inode->i_mode = MSDOS_MKMODE(raw_entry->attr,(IS_NOEXEC(inode)
 417                     ? S_IRUGO|S_IWUGO : S_IRWXUGO) & ~MSDOS_SB(inode->i_sb)->fs_umask) |
 418                     S_IFREG;
 419                 inode->i_op = sb->s_blocksize == 1024
 420                         ? &msdos_file_inode_operations_1024
 421                         : &msdos_file_inode_operations;
 422                 MSDOS_I(inode)->i_start = CF_LE_W(raw_entry->start);
 423                 inode->i_nlink = 1;
 424                 inode->i_size = CF_LE_L(raw_entry->size);
 425         }
 426         MSDOS_I(inode)->i_binary = is_binary(MSDOS_SB(inode->i_sb)->conversion,
 427             raw_entry->ext);
 428         MSDOS_I(inode)->i_attrs = raw_entry->attr & ATTR_UNUSED;
 429         /* this is as close to the truth as we can get ... */
 430         inode->i_blksize = MSDOS_SB(inode->i_sb)->cluster_size*SECTOR_SIZE;
 431         inode->i_blocks = (inode->i_size+inode->i_blksize-1)/
 432             inode->i_blksize*MSDOS_SB(inode->i_sb)->cluster_size;
 433         inode->i_mtime = inode->i_atime = inode->i_ctime =
 434             date_dos2unix(CF_LE_W(raw_entry->time),CF_LE_W(raw_entry->date));
 435         brelse(bh);
 436 }
 437 
 438 
 439 void msdos_write_inode(struct inode *inode)
     /*  */
 440 {
 441         struct super_block *sb = inode->i_sb;
 442         struct buffer_head *bh;
 443         struct msdos_dir_entry *raw_entry;
 444 
 445         inode->i_dirt = 0;
 446         if (inode->i_ino == MSDOS_ROOT_INO || !inode->i_nlink) return;
 447         if (!(bh = bread(inode->i_dev,inode->i_ino >> MSDOS_DPB_BITS,
 448             SECTOR_SIZE))) {
 449                 printk("dev = 0x%04X, ino = %ld\n",inode->i_dev,inode->i_ino);
 450                 panic("msdos_write_inode: unable to read i-node block");
 451         }
 452         raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
 453             [inode->i_ino & (MSDOS_DPB-1)];
 454         if (S_ISDIR(inode->i_mode)) {
 455                 raw_entry->attr = ATTR_DIR;
 456                 raw_entry->size = 0;
 457         }
 458         else {
 459                 raw_entry->attr = ATTR_NONE;
 460                 raw_entry->size = CT_LE_L(inode->i_size);
 461         }
 462         raw_entry->attr |= MSDOS_MKATTR(inode->i_mode) |
 463             MSDOS_I(inode)->i_attrs;
 464         raw_entry->start = CT_LE_L(MSDOS_I(inode)->i_start);
 465         date_unix2dos(inode->i_mtime,&raw_entry->time,&raw_entry->date);
 466         raw_entry->time = CT_LE_W(raw_entry->time);
 467         raw_entry->date = CT_LE_W(raw_entry->date);
 468         mark_buffer_dirty(bh, 1);
 469         brelse(bh);
 470 }
 471 
 472 
 473 int msdos_notify_change(struct inode * inode,struct iattr * attr)
     /*  */
 474 {
 475         int error;
 476 
 477         error = inode_change_ok(inode, attr);
 478         if (error)
 479                 return error;
 480 
 481         if (((attr->ia_valid & ATTR_UID) && 
 482              (attr->ia_uid != MSDOS_SB(inode->i_sb)->fs_uid)) ||
 483             ((attr->ia_valid & ATTR_GID) && 
 484              (attr->ia_gid != MSDOS_SB(inode->i_sb)->fs_gid)) ||
 485             ((attr->ia_valid & ATTR_MODE) &&
 486              (attr->ia_mode & ~MSDOS_VALID_MODE)))
 487                 error = -EPERM;
 488 
 489         if (error)
 490                 return MSDOS_SB(inode->i_sb)->quiet ? 0 : error;
 491 
 492         inode_setattr(inode, attr);
 493 
 494         if (IS_NOEXEC(inode) && !S_ISDIR(inode->i_mode))
 495                 inode->i_mode &= S_IFMT | S_IRUGO | S_IWUGO;
 496         else
 497                 inode->i_mode |= S_IXUGO;
 498 
 499         inode->i_mode = ((inode->i_mode & S_IFMT) | ((((inode->i_mode & S_IRWXU
 500             & ~MSDOS_SB(inode->i_sb)->fs_umask) | S_IRUSR) >> 6)*S_IXUGO)) &
 501             ~MSDOS_SB(inode->i_sb)->fs_umask;
 502         return 0;
 503 }
 504 #ifdef MODULE
 505 
 506 char kernel_version[] = UTS_RELEASE;
 507 
 508 static struct file_system_type msdos_fs_type = {
 509         msdos_read_super, "msdos", 1, NULL
 510 };
 511 
 512 int init_module(void)
     /*  */
 513 {
 514         register_filesystem(&msdos_fs_type);
 515         return 0;
 516 }
 517 
 518 void cleanup_module(void)
     /*  */
 519 {
 520         unregister_filesystem(&msdos_fs_type);
 521 }
 522 
 523 #endif
 524
/* */
root/fs/msdos/inode.c

DEFINITIONS
