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 #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/major.h>
  14 #include <linux/blkdev.h>
  15 #include <linux/fs.h>
  16 #include <linux/stat.h>
  17 #include <linux/locks.h>
  18 
  19 #include "msbuffer.h"
  20 
  21 #ifdef MODULE
  22         #include <linux/module.h>
  23         #include <linux/version.h>
  24 #endif
  25 
  26 #include <asm/segment.h>
  27 
  28 extern int *blksize_size[];
  29 
  30 void msdos_put_inode(struct inode *inode)
     /*  */
  31 {
  32         struct inode *depend;
  33         struct super_block *sb;
  34 
  35         if (inode->i_nlink) {
  36                 if (MSDOS_I(inode)->i_busy) cache_inval_inode(inode);
  37                 return;
  38         }
  39         inode->i_size = 0;
  40         msdos_truncate(inode);
  41         depend = MSDOS_I(inode)->i_depend;
  42         sb = inode->i_sb;
  43         clear_inode(inode);
  44         if (depend) {
  45                 if (MSDOS_I(depend)->i_old != inode) {
  46                         printk("Invalid link (0x%X): expected 0x%X, got 0x%X\n",
  47                             (int) depend,(int) inode,(int) MSDOS_I(depend)->
  48                             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         #ifdef MODULE
  66                 MOD_DEC_USE_COUNT;
  67         #endif
  68         return;
  69 }
  70 
  71 
  72 static struct super_operations msdos_sops = { 
  73         msdos_read_inode,
  74         msdos_notify_change,
  75         msdos_write_inode,
  76         msdos_put_inode,
  77         msdos_put_super,
  78         NULL, /* added in 0.96c */
  79         msdos_statfs,
  80         NULL
  81 };
  82 
  83 
  84 static int parse_options(char *options,char *check,char *conversion,uid_t *uid,
     /*  */
  85     gid_t *gid,int *umask,int *debug,int *fat,int *quiet,
  86         int *blksize)
  87 {
  88         char *this_char,*value;
  89 
  90         *check = 'n';
  91         *conversion = 'b';
  92         *uid = current->uid;
  93         *gid = current->gid;
  94         *umask = current->fs->umask;
  95         *debug = *fat = *quiet = 0;
  96         if (!options) return 1;
  97         for (this_char = strtok(options,","); this_char; this_char = strtok(NULL,",")) {
  98                 if ((value = strchr(this_char,'=')) != NULL)
  99                         *value++ = 0;
 100                 if (!strcmp(this_char,"check") && value) {
 101                         if (value[0] && !value[1] && strchr("rns",*value))
 102                                 *check = *value;
 103                         else if (!strcmp(value,"relaxed")) *check = 'r';
 104                         else if (!strcmp(value,"normal")) *check = 'n';
 105                         else if (!strcmp(value,"strict")) *check = 's';
 106                         else return 0;
 107                 }
 108                 else if (!strcmp(this_char,"conv") && value) {
 109                         if (value[0] && !value[1] && strchr("bta",*value))
 110                                 *conversion = *value;
 111                         else if (!strcmp(value,"binary")) *conversion = 'b';
 112                         else if (!strcmp(value,"text")) *conversion = 't';
 113                         else if (!strcmp(value,"auto")) *conversion = 'a';
 114                         else return 0;
 115                 }
 116                 else if (!strcmp(this_char,"uid")) {
 117                         if (!value || !*value)
 118                                 return 0;
 119                         *uid = simple_strtoul(value,&value,0);
 120                         if (*value)
 121                                 return 0;
 122                 }
 123                 else if (!strcmp(this_char,"gid")) {
 124                         if (!value || !*value)
 125                                 return 0;
 126                         *gid = simple_strtoul(value,&value,0);
 127                         if (*value)
 128                                 return 0;
 129                 }
 130                 else if (!strcmp(this_char,"umask")) {
 131                         if (!value || !*value)
 132                                 return 0;
 133                         *umask = simple_strtoul(value,&value,8);
 134                         if (*value)
 135                                 return 0;
 136                 }
 137                 else if (!strcmp(this_char,"debug")) {
 138                         if (value) return 0;
 139                         *debug = 1;
 140                 }
 141                 else if (!strcmp(this_char,"fat")) {
 142                         if (!value || !*value)
 143                                 return 0;
 144                         *fat = simple_strtoul(value,&value,0);
 145                         if (*value || (*fat != 12 && *fat != 16))
 146                                 return 0;
 147                 }
 148                 else if (!strcmp(this_char,"quiet")) {
 149                         if (value) return 0;
 150                         *quiet = 1;
 151                 }
 152                 else if (!strcmp(this_char,"blocksize")) {
 153                         *blksize = simple_strtoul(value,&value,0);
 154                         if (*value)
 155                                 return 0;
 156                         if (*blksize != 512 && *blksize != 1024){
 157                                 printk ("MSDOS FS: Invalid blocksize (512 or 1024)\n");
 158                         }
 159                 }
 160                 else return 0;
 161         }
 162         return 1;
 163 }
 164 
 165 
 166 /* Read the super block of an MS-DOS FS. */
 167 
 168 struct super_block *msdos_read_super(struct super_block *sb,void *data,
     /*  */
 169                                      int silent)
 170 {
 171         struct buffer_head *bh;
 172         struct msdos_boot_sector *b;
 173         int data_sectors,logical_sector_size,sector_mult;
 174         int debug,error,fat,quiet;
 175         char check,conversion;
 176         uid_t uid;
 177         gid_t gid;
 178         int umask;
 179         int blksize = 512;
 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                 return NULL;
 191         }
 192         cache_init();
 193         lock_super(sb);
 194         /* The first read is always 1024 bytes */
 195         sb->s_blocksize = 1024;
 196         set_blocksize(sb->s_dev, 1024);
 197         bh = bread(sb->s_dev, 0, 1024);
 198         unlock_super(sb);
 199         if (bh == NULL || !msdos_is_uptodate(sb,bh)) {
 200                 brelse (bh);
 201                 sb->s_dev = 0;
 202                 printk("MSDOS bread failed\n");
 203                 return NULL;
 204         }
 205         b = (struct msdos_boot_sector *) bh->b_data;
 206         set_blocksize(sb->s_dev, blksize);
 207 /*
 208  * The DOS3 partition size limit is *not* 32M as many people think.  
 209  * Instead, it is 64K sectors (with the usual sector size being
 210  * 512 bytes, leading to a 32M limit).
 211  * 
 212  * DOS 3 partition managers got around this problem by faking a 
 213  * larger sector size, ie treating multiple physical sectors as 
 214  * a single logical sector.
 215  * 
 216  * We can accommodate this scheme by adjusting our cluster size,
 217  * fat_start, and data_start by an appropriate value.
 218  *
 219  * (by Drew Eckhardt)
 220  */
 221 
 222 #define ROUND_TO_MULTIPLE(n,m) ((n) && (m) ? (n)+(m)-1-((n)-1)%(m) : 0)
 223     /* don't divide by zero */
 224 
 225         logical_sector_size = CF_LE_W(*(unsigned short *) &b->sector_size);
 226         sector_mult = logical_sector_size >> SECTOR_BITS;
 227         MSDOS_SB(sb)->cluster_size = b->cluster_size*sector_mult;
 228         MSDOS_SB(sb)->fats = b->fats;
 229         MSDOS_SB(sb)->fat_start = CF_LE_W(b->reserved)*sector_mult;
 230         MSDOS_SB(sb)->fat_length = CF_LE_W(b->fat_length)*sector_mult;
 231         MSDOS_SB(sb)->dir_start = (CF_LE_W(b->reserved)+b->fats*CF_LE_W(
 232             b->fat_length))*sector_mult;
 233         MSDOS_SB(sb)->dir_entries = CF_LE_W(*((unsigned short *) &b->dir_entries
 234             ));
 235         MSDOS_SB(sb)->data_start = MSDOS_SB(sb)->dir_start+ROUND_TO_MULTIPLE((
 236             MSDOS_SB(sb)->dir_entries << MSDOS_DIR_BITS) >> SECTOR_BITS,
 237             sector_mult);
 238         data_sectors = (CF_LE_W(*((unsigned short *) &b->sectors)) ?
 239             CF_LE_W(*((unsigned short *) &b->sectors)) :
 240             CF_LE_L(b->total_sect))*sector_mult-MSDOS_SB(sb)->data_start;
 241         error = !b->cluster_size || !sector_mult;
 242         if (!error) {
 243                 MSDOS_SB(sb)->clusters = b->cluster_size ? data_sectors/
 244                     b->cluster_size/sector_mult : 0;
 245                 MSDOS_SB(sb)->fat_bits = fat ? fat : MSDOS_SB(sb)->clusters >
 246                     MSDOS_FAT12 ? 16 : 12;
 247                 error = !MSDOS_SB(sb)->fats || (MSDOS_SB(sb)->dir_entries &
 248                     (MSDOS_DPS-1)) || MSDOS_SB(sb)->clusters+2 > MSDOS_SB(sb)->
 249                     fat_length*SECTOR_SIZE*8/MSDOS_SB(sb)->fat_bits ||
 250                     (logical_sector_size & (SECTOR_SIZE-1)) || !b->secs_track ||
 251                     !b->heads;
 252         }
 253         brelse(bh);
 254         /*
 255                 This must be done after the brelse because the bh is a dummy
 256                 allocated by msdos_bread (see buffer.c)
 257         */
 258         sb->s_blocksize = blksize;      /* Using this small block size solve the */
 259                                 /* the misfit with buffer cache and cluster */
 260                                 /* because cluster (DOS) are often aligned */
 261                                 /* on odd sector */
 262         sb->s_blocksize_bits = blksize == 512 ? 9 : 10;
 263         if (error || debug) {
 264                 /* The MSDOS_CAN_BMAP is obsolete, but left just to remember */
 265                 printk("[MS-DOS FS Rel. 12,FAT %d,check=%c,conv=%c,"
 266                     "uid=%d,gid=%d,umask=%03o%s]\n",MSDOS_SB(sb)->fat_bits,check,
 267                     conversion,uid,gid,umask,MSDOS_CAN_BMAP(MSDOS_SB(sb)) ?
 268                     ",bmap" : "");
 269                 printk("[me=0x%x,cs=%d,#f=%d,fs=%d,fl=%d,ds=%d,de=%d,data=%d,"
 270                     "se=%d,ts=%ld,ls=%d]\n",b->media,MSDOS_SB(sb)->cluster_size,
 271                     MSDOS_SB(sb)->fats,MSDOS_SB(sb)->fat_start,MSDOS_SB(sb)->
 272                     fat_length,MSDOS_SB(sb)->dir_start,MSDOS_SB(sb)->dir_entries,
 273                     MSDOS_SB(sb)->data_start,CF_LE_W(*(unsigned short *) &b->
 274                     sectors),b->total_sect,logical_sector_size);
 275                 printk ("Transaction block size = %d\n",blksize);
 276         }
 277         if (error) {
 278                 if (!silent)
 279                         printk("VFS: Can't find a valid MSDOS filesystem on dev 0x%04x.\n",
 280                                    sb->s_dev);
 281                 sb->s_dev = 0;
 282                 return NULL;
 283         }
 284         sb->s_magic = MSDOS_SUPER_MAGIC;
 285         MSDOS_SB(sb)->name_check = check;
 286         MSDOS_SB(sb)->conversion = conversion;
 287         /* set up enough so that it can read an inode */
 288         sb->s_op = &msdos_sops;
 289         MSDOS_SB(sb)->fs_uid = uid;
 290         MSDOS_SB(sb)->fs_gid = gid;
 291         MSDOS_SB(sb)->fs_umask = umask;
 292         MSDOS_SB(sb)->quiet = quiet;
 293         MSDOS_SB(sb)->free_clusters = -1; /* don't know yet */
 294         MSDOS_SB(sb)->fat_wait = NULL;
 295         MSDOS_SB(sb)->fat_lock = 0;
 296         MSDOS_SB(sb)->prev_free = 0;
 297         if (!(sb->s_mounted = iget(sb,MSDOS_ROOT_INO))) {
 298                 sb->s_dev = 0;
 299                 printk("get root inode failed\n");
 300                 return NULL;
 301         }
 302         #ifdef MODULE
 303                 MOD_INC_USE_COUNT;
 304         #endif
 305         return sb;
 306 }
 307 
 308 
 309 void msdos_statfs(struct super_block *sb,struct statfs *buf)
     /*  */
 310 {
 311         int free,nr;
 312 
 313         put_fs_long(sb->s_magic,&buf->f_type);
 314         put_fs_long(MSDOS_SB(sb)->cluster_size*SECTOR_SIZE,&buf->f_bsize);
 315         put_fs_long(MSDOS_SB(sb)->clusters,&buf->f_blocks);
 316         lock_fat(sb);
 317         if (MSDOS_SB(sb)->free_clusters != -1)
 318                 free = MSDOS_SB(sb)->free_clusters;
 319         else {
 320                 free = 0;
 321                 for (nr = 2; nr < MSDOS_SB(sb)->clusters+2; nr++)
 322                         if (!fat_access(sb,nr,-1)) free++;
 323                 MSDOS_SB(sb)->free_clusters = free;
 324         }
 325         unlock_fat(sb);
 326         put_fs_long(free,&buf->f_bfree);
 327         put_fs_long(free,&buf->f_bavail);
 328         put_fs_long(0,&buf->f_files);
 329         put_fs_long(0,&buf->f_ffree);
 330         put_fs_long(12,&buf->f_namelen);
 331 }
 332 
 333 
 334 int msdos_bmap(struct inode *inode,int block)
     /*  */
 335 {
 336         struct msdos_sb_info *sb;
 337         int cluster,offset;
 338 
 339         sb = MSDOS_SB(inode->i_sb);
 340         if (inode->i_ino == MSDOS_ROOT_INO) {
 341                 return sb->dir_start + block;
 342         }
 343         cluster = block/sb->cluster_size;
 344         offset = block % sb->cluster_size;
 345         if (!(cluster = get_cluster(inode,cluster))) return 0;
 346         return (cluster-2)*sb->cluster_size+sb->data_start+offset;
 347 }
 348 
 349 
 350 void msdos_read_inode(struct inode *inode)
     /*  */
 351 {
 352         struct super_block *sb = inode->i_sb;
 353         struct buffer_head *bh;
 354         struct msdos_dir_entry *raw_entry;
 355         int nr;
 356 
 357 /* printk("read inode %d\n",inode->i_ino); */
 358         MSDOS_I(inode)->i_busy = 0;
 359         MSDOS_I(inode)->i_depend = MSDOS_I(inode)->i_old = NULL;
 360         MSDOS_I(inode)->i_binary = 1;
 361         inode->i_uid = MSDOS_SB(inode->i_sb)->fs_uid;
 362         inode->i_gid = MSDOS_SB(inode->i_sb)->fs_gid;
 363         if (inode->i_ino == MSDOS_ROOT_INO) {
 364                 inode->i_mode = (S_IRWXUGO & ~MSDOS_SB(inode->i_sb)->fs_umask) |
 365                     S_IFDIR;
 366                 inode->i_op = &msdos_dir_inode_operations;
 367                 inode->i_nlink = msdos_subdirs(inode)+2;
 368                     /* subdirs (neither . nor ..) plus . and "self" */
 369                 inode->i_size = MSDOS_SB(inode->i_sb)->dir_entries*
 370                     sizeof(struct msdos_dir_entry);
 371                 inode->i_blksize = MSDOS_SB(inode->i_sb)->cluster_size*
 372                     SECTOR_SIZE;
 373                 inode->i_blocks = (inode->i_size+inode->i_blksize-1)/
 374                     inode->i_blksize*MSDOS_SB(inode->i_sb)->cluster_size;
 375                 MSDOS_I(inode)->i_start = 0;
 376                 MSDOS_I(inode)->i_attrs = 0;
 377                 inode->i_mtime = inode->i_atime = inode->i_ctime = 0;
 378                 return;
 379         }
 380         if (!(bh = bread(inode->i_dev,inode->i_ino >> MSDOS_DPB_BITS,
 381             SECTOR_SIZE))) {
 382                 printk("dev = 0x%04X, ino = %ld\n",inode->i_dev,inode->i_ino);
 383                 panic("msdos_read_inode: unable to read i-node block");
 384         }
 385         raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
 386             [inode->i_ino & (MSDOS_DPB-1)];
 387         if ((raw_entry->attr & ATTR_DIR) && !IS_FREE(raw_entry->name)) {
 388                 inode->i_mode = MSDOS_MKMODE(raw_entry->attr,S_IRWXUGO &
 389                     ~MSDOS_SB(inode->i_sb)->fs_umask) | S_IFDIR;
 390                 inode->i_op = &msdos_dir_inode_operations;
 391                 MSDOS_I(inode)->i_start = CF_LE_W(raw_entry->start);
 392                 inode->i_nlink = msdos_subdirs(inode);
 393                     /* includes .., compensating for "self" */
 394 #ifdef DEBUG
 395                 if (!inode->i_nlink) {
 396                         printk("directory %d: i_nlink == 0\n",inode->i_ino);
 397                         inode->i_nlink = 1;
 398                 }
 399 #endif
 400                 inode->i_size = 0;
 401                 if ((nr = CF_LE_W(raw_entry->start)) != 0)
 402                         while (nr != -1) {
 403                                 inode->i_size += SECTOR_SIZE*MSDOS_SB(inode->
 404                                     i_sb)->cluster_size;
 405                                 if (!(nr = fat_access(inode->i_sb,nr,-1))) {
 406                                         printk("Directory %ld: bad FAT\n",
 407                                             inode->i_ino);
 408                                         break;
 409                                 }
 410                         }
 411         }
 412         else {
 413                 inode->i_mode = MSDOS_MKMODE(raw_entry->attr,(IS_NOEXEC(inode)
 414                     ? S_IRUGO|S_IWUGO : S_IRWXUGO) & ~MSDOS_SB(inode->i_sb)->fs_umask) |
 415                     S_IFREG;
 416                 inode->i_op = sb->s_blocksize == 1024
 417                         ? &msdos_file_inode_operations_1024
 418                         : &msdos_file_inode_operations;
 419                 MSDOS_I(inode)->i_start = CF_LE_W(raw_entry->start);
 420                 inode->i_nlink = 1;
 421                 inode->i_size = CF_LE_L(raw_entry->size);
 422         }
 423         MSDOS_I(inode)->i_binary = is_binary(MSDOS_SB(inode->i_sb)->conversion,
 424             raw_entry->ext);
 425         MSDOS_I(inode)->i_attrs = raw_entry->attr & ATTR_UNUSED;
 426         /* this is as close to the truth as we can get ... */
 427         inode->i_blksize = MSDOS_SB(inode->i_sb)->cluster_size*SECTOR_SIZE;
 428         inode->i_blocks = (inode->i_size+inode->i_blksize-1)/
 429             inode->i_blksize*MSDOS_SB(inode->i_sb)->cluster_size;
 430         inode->i_mtime = inode->i_atime = inode->i_ctime =
 431             date_dos2unix(CF_LE_W(raw_entry->time),CF_LE_W(raw_entry->date));
 432         brelse(bh);
 433 }
 434 
 435 
 436 void msdos_write_inode(struct inode *inode)
     /*  */
 437 {
 438         struct super_block *sb = inode->i_sb;
 439         struct buffer_head *bh;
 440         struct msdos_dir_entry *raw_entry;
 441 
 442         inode->i_dirt = 0;
 443         if (inode->i_ino == MSDOS_ROOT_INO || !inode->i_nlink) return;
 444         if (!(bh = bread(inode->i_dev,inode->i_ino >> MSDOS_DPB_BITS,
 445             SECTOR_SIZE))) {
 446                 printk("dev = 0x%04X, ino = %ld\n",inode->i_dev,inode->i_ino);
 447                 panic("msdos_write_inode: unable to read i-node block");
 448         }
 449         raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
 450             [inode->i_ino & (MSDOS_DPB-1)];
 451         if (S_ISDIR(inode->i_mode)) {
 452                 raw_entry->attr = ATTR_DIR;
 453                 raw_entry->size = 0;
 454         }
 455         else {
 456                 raw_entry->attr = ATTR_NONE;
 457                 raw_entry->size = CT_LE_L(inode->i_size);
 458         }
 459         raw_entry->attr |= MSDOS_MKATTR(inode->i_mode) |
 460             MSDOS_I(inode)->i_attrs;
 461         raw_entry->start = CT_LE_L(MSDOS_I(inode)->i_start);
 462         date_unix2dos(inode->i_mtime,&raw_entry->time,&raw_entry->date);
 463         raw_entry->time = CT_LE_W(raw_entry->time);
 464         raw_entry->date = CT_LE_W(raw_entry->date);
 465         mark_buffer_dirty(bh, 1);
 466         brelse(bh);
 467 }
 468 
 469 
 470 int msdos_notify_change(struct inode * inode,struct iattr * attr)
     /*  */
 471 {
 472         int error;
 473 
 474         error = inode_change_ok(inode, attr);
 475         if (error)
 476                 return error;
 477 
 478         if (((attr->ia_valid & ATTR_UID) && 
 479              (attr->ia_uid != MSDOS_SB(inode->i_sb)->fs_uid)) ||
 480             ((attr->ia_valid & ATTR_GID) && 
 481              (attr->ia_gid != MSDOS_SB(inode->i_sb)->fs_gid)) ||
 482             ((attr->ia_valid & ATTR_MODE) &&
 483              (attr->ia_mode & ~MSDOS_VALID_MODE)))
 484                 error = -EPERM;
 485 
 486         if (error)
 487                 return MSDOS_SB(inode->i_sb)->quiet ? 0 : error;
 488 
 489         inode_setattr(inode, attr);
 490 
 491         if (IS_NOEXEC(inode) && !S_ISDIR(inode->i_mode))
 492                 inode->i_mode &= S_IFMT | S_IRUGO | S_IWUGO;
 493         else
 494                 inode->i_mode |= S_IXUGO;
 495 
 496         inode->i_mode = ((inode->i_mode & S_IFMT) | ((((inode->i_mode & S_IRWXU
 497             & ~MSDOS_SB(inode->i_sb)->fs_umask) | S_IRUSR) >> 6)*S_IXUGO)) &
 498             ~MSDOS_SB(inode->i_sb)->fs_umask;
 499         return 0;
 500 }
 501 #ifdef MODULE
 502 
 503 char kernel_version[] = UTS_RELEASE;
 504 
 505 static struct file_system_type msdos_fs_type = {
 506         msdos_read_super, "msdos", 1, NULL
 507 };
 508 
 509 int init_module(void)
     /*  */
 510 {
 511         register_filesystem(&msdos_fs_type);
 512         return 0;
 513 }
 514 
 515 void cleanup_module(void)
     /*  */
 516 {
 517         if (MOD_IN_USE)
 518                 printk("msdos: device busy, remove delayed\n");
 519         else
 520         {
 521                 unregister_filesystem(&msdos_fs_type);
 522         }
 523 }
 524 
 525 #endif
 526
/* */
root/fs/msdos/inode.c

DEFINITIONS
