fs/adfs/inode.c

   1 /*
   2  *  linux/fs/adfs/inode.c
   3  *
   4  *  Copyright (C) 1997-1999 Russell King
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #include <linux/errno.h>
  11 #include <linux/fs.h>
  12 #include <linux/adfs_fs.h>
  13 #include <linux/time.h>
  14 #include <linux/stat.h>
  15 #include <linux/string.h>
  16 #include <linux/mm.h>
  17 #include <linux/smp_lock.h>
  18 #include <linux/module.h>
  19 #include <linux/buffer_head.h>
  20
  21 #include "adfs.h"
  22
  23 /*
  24  * Lookup/Create a block at offset 'block' into 'inode'.  We currently do
  25  * not support creation of new blocks, so we return -EIO for this case.
  26  */
  27 static int
  28 adfs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh,
  29                int create)
  30 {
  31         if (block < 0)
  32                 goto abort_negative;
  33
  34         if (!create) {
  35                 if (block >= inode->i_blocks)
  36                         goto abort_toobig;
  37
  38                 block = __adfs_block_map(inode->i_sb, inode->i_ino, block);
  39                 if (block)
  40                         map_bh(bh, inode->i_sb, block);
  41                 return 0;
  42         }
  43         /* don't support allocation of blocks yet */
  44         return -EIO;
  45
  46 abort_negative:
  47         adfs_error(inode->i_sb, "block %d < 0", block);
  48         return -EIO;
  49
  50 abort_toobig:
  51         return 0;
  52 }
  53
  54 static int adfs_writepage(struct page *page, struct writeback_control *wbc)
  55 {
  56         return block_write_full_page(page, adfs_get_block, wbc);
  57 }
  58
  59 static int adfs_readpage(struct file *file, struct page *page)
  60 {
  61         return block_read_full_page(page, adfs_get_block);
  62 }
  63
  64 static int adfs_prepare_write(struct file *file, struct page *page, unsigned int from, unsigned int to)
  65 {
  66         return cont_prepare_write(page, from, to, adfs_get_block,
  67                 &ADFS_I(page->mapping->host)->mmu_private);
  68 }
  69
  70 static sector_t _adfs_bmap(struct address_space *mapping, sector_t block)
  71 {
  72         return generic_block_bmap(mapping, block, adfs_get_block);
  73 }
  74
  75 static const struct address_space_operations adfs_aops = {
  76         .readpage       = adfs_readpage,
  77         .writepage      = adfs_writepage,
  78         .sync_page      = block_sync_page,
  79         .prepare_write  = adfs_prepare_write,
  80         .commit_write   = generic_commit_write,
  81         .bmap           = _adfs_bmap
  82 };
  83
  84 static inline unsigned int
  85 adfs_filetype(struct inode *inode)
  86 {
  87         unsigned int type;
  88
  89         if (ADFS_I(inode)->stamped)
  90                 type = (ADFS_I(inode)->loadaddr >> 8) & 0xfff;
  91         else
  92                 type = (unsigned int) -1;
  93
  94         return type;
  95 }
  96
  97 /*
  98  * Convert ADFS attributes and filetype to Linux permission.
  99  */
 100 static umode_t
 101 adfs_atts2mode(struct super_block *sb, struct inode *inode)
 102 {
 103         unsigned int filetype, attr = ADFS_I(inode)->attr;
 104         umode_t mode, rmask;
 105         struct adfs_sb_info *asb = ADFS_SB(sb);
 106
 107         if (attr & ADFS_NDA_DIRECTORY) {
 108                 mode = S_IRUGO & asb->s_owner_mask;
 109                 return S_IFDIR | S_IXUGO | mode;
 110         }
 111
 112         filetype = adfs_filetype(inode);
 113
 114         switch (filetype) {
 115         case 0xfc0:     /* LinkFS */
 116                 return S_IFLNK|S_IRWXUGO;
 117
 118         case 0xfe6:     /* UnixExec */
 119                 rmask = S_IRUGO | S_IXUGO;
 120                 break;
 121
 122         default:
 123                 rmask = S_IRUGO;
 124         }
 125
 126         mode = S_IFREG;
 127
 128         if (attr & ADFS_NDA_OWNER_READ)
 129                 mode |= rmask & asb->s_owner_mask;
 130
 131         if (attr & ADFS_NDA_OWNER_WRITE)
 132                 mode |= S_IWUGO & asb->s_owner_mask;
 133
 134         if (attr & ADFS_NDA_PUBLIC_READ)
 135                 mode |= rmask & asb->s_other_mask;
 136
 137         if (attr & ADFS_NDA_PUBLIC_WRITE)
 138                 mode |= S_IWUGO & asb->s_other_mask;
 139         return mode;
 140 }
 141
 142 /*
 143  * Convert Linux permission to ADFS attribute.  We try to do the reverse
 144  * of atts2mode, but there is not a 1:1 translation.
 145  */
 146 static int
 147 adfs_mode2atts(struct super_block *sb, struct inode *inode)
 148 {
 149         umode_t mode;
 150         int attr;
 151         struct adfs_sb_info *asb = ADFS_SB(sb);
 152
 153         /* FIXME: should we be able to alter a link? */
 154         if (S_ISLNK(inode->i_mode))
 155                 return ADFS_I(inode)->attr;
 156
 157         if (S_ISDIR(inode->i_mode))
 158                 attr = ADFS_NDA_DIRECTORY;
 159         else
 160                 attr = 0;
 161
 162         mode = inode->i_mode & asb->s_owner_mask;
 163         if (mode & S_IRUGO)
 164                 attr |= ADFS_NDA_OWNER_READ;
 165         if (mode & S_IWUGO)
 166                 attr |= ADFS_NDA_OWNER_WRITE;
 167
 168         mode = inode->i_mode & asb->s_other_mask;
 169         mode &= ~asb->s_owner_mask;
 170         if (mode & S_IRUGO)
 171                 attr |= ADFS_NDA_PUBLIC_READ;
 172         if (mode & S_IWUGO)
 173                 attr |= ADFS_NDA_PUBLIC_WRITE;
 174
 175         return attr;
 176 }
 177
 178 /*
 179  * Convert an ADFS time to Unix time.  ADFS has a 40-bit centi-second time
 180  * referenced to 1 Jan 1900 (til 2248)
 181  */
 182 static void
 183 adfs_adfs2unix_time(struct timespec *tv, struct inode *inode)
 184 {
 185         unsigned int high, low;
 186
 187         if (ADFS_I(inode)->stamped == 0)
 188                 goto cur_time;
 189
 190         high = ADFS_I(inode)->loadaddr << 24;
 191         low  = ADFS_I(inode)->execaddr;
 192
 193         high |= low >> 8;
 194         low  &= 255;
 195
 196         /* Files dated pre  01 Jan 1970 00:00:00. */
 197         if (high < 0x336e996a)
 198                 goto too_early;
 199
 200         /* Files dated post 18 Jan 2038 03:14:05. */
 201         if (high >= 0x656e9969)
 202                 goto too_late;
 203
 204         /* discard 2208988800 (0x336e996a00) seconds of time */
 205         high -= 0x336e996a;
 206
 207         /* convert 40-bit centi-seconds to 32-bit seconds */
 208         tv->tv_sec = (((high % 100) << 8) + low) / 100 + (high / 100 << 8);
 209         tv->tv_nsec = 0;
 210         return;
 211
 212  cur_time:
 213         *tv = CURRENT_TIME_SEC;
 214         return;
 215
 216  too_early:
 217         tv->tv_sec = tv->tv_nsec = 0;
 218         return;
 219
 220  too_late:
 221         tv->tv_sec = 0x7ffffffd;
 222         tv->tv_nsec = 0;
 223         return;
 224 }
 225
 226 /*
 227  * Convert an Unix time to ADFS time.  We only do this if the entry has a
 228  * time/date stamp already.
 229  */
 230 static void
 231 adfs_unix2adfs_time(struct inode *inode, unsigned int secs)
 232 {
 233         unsigned int high, low;
 234
 235         if (ADFS_I(inode)->stamped) {
 236                 /* convert 32-bit seconds to 40-bit centi-seconds */
 237                 low  = (secs & 255) * 100;
 238                 high = (secs / 256) * 100 + (low >> 8) + 0x336e996a;
 239
 240                 ADFS_I(inode)->loadaddr = (high >> 24) |
 241                                 (ADFS_I(inode)->loadaddr & ~0xff);
 242                 ADFS_I(inode)->execaddr = (low & 255) | (high << 8);
 243         }
 244 }
 245
 246 /*
 247  * Fill in the inode information from the object information.
 248  *
 249  * Note that this is an inode-less filesystem, so we can't use the inode
 250  * number to reference the metadata on the media.  Instead, we use the
 251  * inode number to hold the object ID, which in turn will tell us where
 252  * the data is held.  We also save the parent object ID, and with these
 253  * two, we can locate the metadata.
 254  *
 255  * This does mean that we rely on an objects parent remaining the same at
 256  * all times - we cannot cope with a cross-directory rename (yet).
 257  */
 258 struct inode *
 259 adfs_iget(struct super_block *sb, struct object_info *obj)
 260 {
 261         struct inode *inode;
 262
 263         inode = new_inode(sb);
 264         if (!inode)
 265                 goto out;
 266
 267         inode->i_uid     = ADFS_SB(sb)->s_uid;
 268         inode->i_gid     = ADFS_SB(sb)->s_gid;
 269         inode->i_ino     = obj->file_id;
 270         inode->i_size    = obj->size;
 271         inode->i_nlink   = 2;
 272         inode->i_blocks  = (inode->i_size + sb->s_blocksize - 1) >>
 273                             sb->s_blocksize_bits;
 274
 275         /*
 276          * we need to save the parent directory ID so that
 277          * write_inode can update the directory information
 278          * for this file.  This will need special handling
 279          * for cross-directory renames.
 280          */
 281         ADFS_I(inode)->parent_id = obj->parent_id;
 282         ADFS_I(inode)->loadaddr  = obj->loadaddr;
 283         ADFS_I(inode)->execaddr  = obj->execaddr;
 284         ADFS_I(inode)->attr      = obj->attr;
 285         ADFS_I(inode)->stamped    = ((obj->loadaddr & 0xfff00000) == 0xfff00000);
 286
 287         inode->i_mode    = adfs_atts2mode(sb, inode);
 288         adfs_adfs2unix_time(&inode->i_mtime, inode);
 289         inode->i_atime = inode->i_mtime;
 290         inode->i_ctime = inode->i_mtime;
 291
 292         if (S_ISDIR(inode->i_mode)) {
 293                 inode->i_op     = &adfs_dir_inode_operations;
 294                 inode->i_fop    = &adfs_dir_operations;
 295         } else if (S_ISREG(inode->i_mode)) {
 296                 inode->i_op     = &adfs_file_inode_operations;
 297                 inode->i_fop    = &adfs_file_operations;
 298                 inode->i_mapping->a_ops = &adfs_aops;
 299                 ADFS_I(inode)->mmu_private = inode->i_size;
 300         }
 301
 302         insert_inode_hash(inode);
 303
 304 out:
 305         return inode;
 306 }
 307
 308 /*
 309  * Validate and convert a changed access mode/time to their ADFS equivalents.
 310  * adfs_write_inode will actually write the information back to the directory
 311  * later.
 312  */
 313 int
 314 adfs_notify_change(struct dentry *dentry, struct iattr *attr)
 315 {
 316         struct inode *inode = dentry->d_inode;
 317         struct super_block *sb = inode->i_sb;
 318         unsigned int ia_valid = attr->ia_valid;
 319         int error;
 320
 321         lock_kernel();
 322
 323         error = inode_change_ok(inode, attr);
 324
 325         /*
 326          * we can't change the UID or GID of any file -
 327          * we have a global UID/GID in the superblock
 328          */
 329         if ((ia_valid & ATTR_UID && attr->ia_uid != ADFS_SB(sb)->s_uid) ||
 330             (ia_valid & ATTR_GID && attr->ia_gid != ADFS_SB(sb)->s_gid))
 331                 error = -EPERM;
 332
 333         if (error)
 334                 goto out;
 335
 336         if (ia_valid & ATTR_SIZE)
 337                 error = vmtruncate(inode, attr->ia_size);
 338
 339         if (error)
 340                 goto out;
 341
 342         if (ia_valid & ATTR_MTIME) {
 343                 inode->i_mtime = attr->ia_mtime;
 344                 adfs_unix2adfs_time(inode, attr->ia_mtime.tv_sec);
 345         }
 346         /*
 347          * FIXME: should we make these == to i_mtime since we don't
 348          * have the ability to represent them in our filesystem?
 349          */
 350         if (ia_valid & ATTR_ATIME)
 351                 inode->i_atime = attr->ia_atime;
 352         if (ia_valid & ATTR_CTIME)
 353                 inode->i_ctime = attr->ia_ctime;
 354         if (ia_valid & ATTR_MODE) {
 355                 ADFS_I(inode)->attr = adfs_mode2atts(sb, inode);
 356                 inode->i_mode = adfs_atts2mode(sb, inode);
 357         }
 358
 359         /*
 360          * FIXME: should we be marking this inode dirty even if
 361          * we don't have any metadata to write back?
 362          */
 363         if (ia_valid & (ATTR_SIZE | ATTR_MTIME | ATTR_MODE))
 364                 mark_inode_dirty(inode);
 365 out:
 366         unlock_kernel();
 367         return error;
 368 }
 369
 370 /*
 371  * write an existing inode back to the directory, and therefore the disk.
 372  * The adfs-specific inode data has already been updated by
 373  * adfs_notify_change()
 374  */
 375 int adfs_write_inode(struct inode *inode, int unused)
 376 {
 377         struct super_block *sb = inode->i_sb;
 378         struct object_info obj;
 379         int ret;
 380
 381         lock_kernel();
 382         obj.file_id     = inode->i_ino;
 383         obj.name_len    = 0;
 384         obj.parent_id   = ADFS_I(inode)->parent_id;
 385         obj.loadaddr    = ADFS_I(inode)->loadaddr;
 386         obj.execaddr    = ADFS_I(inode)->execaddr;
 387         obj.attr        = ADFS_I(inode)->attr;
 388         obj.size        = inode->i_size;
 389
 390         ret = adfs_dir_update(sb, &obj);
 391         unlock_kernel();
 392         return ret;
 393 }
 394 MODULE_LICENSE("GPL");