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