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_write_begin(struct file *file, struct address_space *mapping,
  65                         loff_t pos, unsigned len, unsigned flags,
  66                         struct page **pagep, void **fsdata)
  67 {
  68         *pagep = NULL;
  69         return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
  70                                 adfs_get_block,
  71                                 &ADFS_I(mapping->host)->mmu_private);
  72 }
  73
  74 static sector_t _adfs_bmap(struct address_space *mapping, sector_t block)
  75 {
  76         return generic_block_bmap(mapping, block, adfs_get_block);
  77 }
  78
  79 static const struct address_space_operations adfs_aops = {
  80         .readpage       = adfs_readpage,
  81         .writepage      = adfs_writepage,
  82         .sync_page      = block_sync_page,
  83         .write_begin    = adfs_write_begin,
  84         .write_end      = generic_write_end,
  85         .bmap           = _adfs_bmap
  86 };
  87
  88 static inline unsigned int
  89 adfs_filetype(struct inode *inode)
  90 {
  91         unsigned int type;
  92
  93         if (ADFS_I(inode)->stamped)
  94                 type = (ADFS_I(inode)->loadaddr >> 8) & 0xfff;
  95         else
  96                 type = (unsigned int) -1;
  97
  98         return type;
  99 }
 100
 101 /*
 102  * Convert ADFS attributes and filetype to Linux permission.
 103  */
 104 static umode_t
 105 adfs_atts2mode(struct super_block *sb, struct inode *inode)
 106 {
 107         unsigned int filetype, attr = ADFS_I(inode)->attr;
 108         umode_t mode, rmask;
 109         struct adfs_sb_info *asb = ADFS_SB(sb);
 110
 111         if (attr & ADFS_NDA_DIRECTORY) {
 112                 mode = S_IRUGO & asb->s_owner_mask;
 113                 return S_IFDIR | S_IXUGO | mode;
 114         }
 115
 116         filetype = adfs_filetype(inode);
 117
 118         switch (filetype) {
 119         case 0xfc0:     /* LinkFS */
 120                 return S_IFLNK|S_IRWXUGO;
 121
 122         case 0xfe6:     /* UnixExec */
 123                 rmask = S_IRUGO | S_IXUGO;
 124                 break;
 125
 126         default:
 127                 rmask = S_IRUGO;
 128         }
 129
 130         mode = S_IFREG;
 131
 132         if (attr & ADFS_NDA_OWNER_READ)
 133                 mode |= rmask & asb->s_owner_mask;
 134
 135         if (attr & ADFS_NDA_OWNER_WRITE)
 136                 mode |= S_IWUGO & asb->s_owner_mask;
 137
 138         if (attr & ADFS_NDA_PUBLIC_READ)
 139                 mode |= rmask & asb->s_other_mask;
 140
 141         if (attr & ADFS_NDA_PUBLIC_WRITE)
 142                 mode |= S_IWUGO & asb->s_other_mask;
 143         return mode;
 144 }
 145
 146 /*
 147  * Convert Linux permission to ADFS attribute.  We try to do the reverse
 148  * of atts2mode, but there is not a 1:1 translation.
 149  */
 150 static int
 151 adfs_mode2atts(struct super_block *sb, struct inode *inode)
 152 {
 153         umode_t mode;
 154         int attr;
 155         struct adfs_sb_info *asb = ADFS_SB(sb);
 156
 157         /* FIXME: should we be able to alter a link? */
 158         if (S_ISLNK(inode->i_mode))
 159                 return ADFS_I(inode)->attr;
 160
 161         if (S_ISDIR(inode->i_mode))
 162                 attr = ADFS_NDA_DIRECTORY;
 163         else
 164                 attr = 0;
 165
 166         mode = inode->i_mode & asb->s_owner_mask;
 167         if (mode & S_IRUGO)
 168                 attr |= ADFS_NDA_OWNER_READ;
 169         if (mode & S_IWUGO)
 170                 attr |= ADFS_NDA_OWNER_WRITE;
 171
 172         mode = inode->i_mode & asb->s_other_mask;
 173         mode &= ~asb->s_owner_mask;
 174         if (mode & S_IRUGO)
 175                 attr |= ADFS_NDA_PUBLIC_READ;
 176         if (mode & S_IWUGO)
 177                 attr |= ADFS_NDA_PUBLIC_WRITE;
 178
 179         return attr;
 180 }
 181
 182 /*
 183  * Convert an ADFS time to Unix time.  ADFS has a 40-bit centi-second time
 184  * referenced to 1 Jan 1900 (til 2248)
 185  */
 186 static void
 187 adfs_adfs2unix_time(struct timespec *tv, struct inode *inode)
 188 {
 189         unsigned int high, low;
 190
 191         if (ADFS_I(inode)->stamped == 0)
 192                 goto cur_time;
 193
 194         high = ADFS_I(inode)->loadaddr << 24;
 195         low  = ADFS_I(inode)->execaddr;
 196
 197         high |= low >> 8;
 198         low  &= 255;
 199
 200         /* Files dated pre  01 Jan 1970 00:00:00. */
 201         if (high < 0x336e996a)
 202                 goto too_early;
 203
 204         /* Files dated post 18 Jan 2038 03:14:05. */
 205         if (high >= 0x656e9969)
 206                 goto too_late;
 207
 208         /* discard 2208988800 (0x336e996a00) seconds of time */
 209         high -= 0x336e996a;
 210
 211         /* convert 40-bit centi-seconds to 32-bit seconds */
 212         tv->tv_sec = (((high % 100) << 8) + low) / 100 + (high / 100 << 8);
 213         tv->tv_nsec = 0;
 214         return;
 215
 216  cur_time:
 217         *tv = CURRENT_TIME_SEC;
 218         return;
 219
 220  too_early:
 221         tv->tv_sec = tv->tv_nsec = 0;
 222         return;
 223
 224  too_late:
 225         tv->tv_sec = 0x7ffffffd;
 226         tv->tv_nsec = 0;
 227         return;
 228 }
 229
 230 /*
 231  * Convert an Unix time to ADFS time.  We only do this if the entry has a
 232  * time/date stamp already.
 233  */
 234 static void
 235 adfs_unix2adfs_time(struct inode *inode, unsigned int secs)
 236 {
 237         unsigned int high, low;
 238
 239         if (ADFS_I(inode)->stamped) {
 240                 /* convert 32-bit seconds to 40-bit centi-seconds */
 241                 low  = (secs & 255) * 100;
 242                 high = (secs / 256) * 100 + (low >> 8) + 0x336e996a;
 243
 244                 ADFS_I(inode)->loadaddr = (high >> 24) |
 245                                 (ADFS_I(inode)->loadaddr & ~0xff);
 246                 ADFS_I(inode)->execaddr = (low & 255) | (high << 8);
 247         }
 248 }
 249
 250 /*
 251  * Fill in the inode information from the object information.
 252  *
 253  * Note that this is an inode-less filesystem, so we can't use the inode
 254  * number to reference the metadata on the media.  Instead, we use the
 255  * inode number to hold the object ID, which in turn will tell us where
 256  * the data is held.  We also save the parent object ID, and with these
 257  * two, we can locate the metadata.
 258  *
 259  * This does mean that we rely on an objects parent remaining the same at
 260  * all times - we cannot cope with a cross-directory rename (yet).
 261  */
 262 struct inode *
 263 adfs_iget(struct super_block *sb, struct object_info *obj)
 264 {
 265         struct inode *inode;
 266
 267         inode = new_inode(sb);
 268         if (!inode)
 269                 goto out;
 270
 271         inode->i_uid     = ADFS_SB(sb)->s_uid;
 272         inode->i_gid     = ADFS_SB(sb)->s_gid;
 273         inode->i_ino     = obj->file_id;
 274         inode->i_size    = obj->size;
 275         inode->i_nlink   = 2;
 276         inode->i_blocks  = (inode->i_size + sb->s_blocksize - 1) >>
 277                             sb->s_blocksize_bits;
 278
 279         /*
 280          * we need to save the parent directory ID so that
 281          * write_inode can update the directory information
 282          * for this file.  This will need special handling
 283          * for cross-directory renames.
 284          */
 285         ADFS_I(inode)->parent_id = obj->parent_id;
 286         ADFS_I(inode)->loadaddr  = obj->loadaddr;
 287         ADFS_I(inode)->execaddr  = obj->execaddr;
 288         ADFS_I(inode)->attr      = obj->attr;
 289         ADFS_I(inode)->stamped    = ((obj->loadaddr & 0xfff00000) == 0xfff00000);
 290
 291         inode->i_mode    = adfs_atts2mode(sb, inode);
 292         adfs_adfs2unix_time(&inode->i_mtime, inode);
 293         inode->i_atime = inode->i_mtime;
 294         inode->i_ctime = inode->i_mtime;
 295
 296         if (S_ISDIR(inode->i_mode)) {
 297                 inode->i_op     = &adfs_dir_inode_operations;
 298                 inode->i_fop    = &adfs_dir_operations;
 299         } else if (S_ISREG(inode->i_mode)) {
 300                 inode->i_op     = &adfs_file_inode_operations;
 301                 inode->i_fop    = &adfs_file_operations;
 302                 inode->i_mapping->a_ops = &adfs_aops;
 303                 ADFS_I(inode)->mmu_private = inode->i_size;
 304         }
 305
 306         insert_inode_hash(inode);
 307
 308 out:
 309         return inode;
 310 }
 311
 312 /*
 313  * Validate and convert a changed access mode/time to their ADFS equivalents.
 314  * adfs_write_inode will actually write the information back to the directory
 315  * later.
 316  */
 317 int
 318 adfs_notify_change(struct dentry *dentry, struct iattr *attr)
 319 {
 320         struct inode *inode = dentry->d_inode;
 321         struct super_block *sb = inode->i_sb;
 322         unsigned int ia_valid = attr->ia_valid;
 323         int error;
 324
 325         lock_kernel();
 326
 327         error = inode_change_ok(inode, attr);
 328
 329         /*
 330          * we can't change the UID or GID of any file -
 331          * we have a global UID/GID in the superblock
 332          */
 333         if ((ia_valid & ATTR_UID && attr->ia_uid != ADFS_SB(sb)->s_uid) ||
 334             (ia_valid & ATTR_GID && attr->ia_gid != ADFS_SB(sb)->s_gid))
 335                 error = -EPERM;
 336
 337         if (error)
 338                 goto out;
 339
 340         if (ia_valid & ATTR_SIZE)
 341                 error = vmtruncate(inode, attr->ia_size);
 342
 343         if (error)
 344                 goto out;
 345
 346         if (ia_valid & ATTR_MTIME) {
 347                 inode->i_mtime = attr->ia_mtime;
 348                 adfs_unix2adfs_time(inode, attr->ia_mtime.tv_sec);
 349         }
 350         /*
 351          * FIXME: should we make these == to i_mtime since we don't
 352          * have the ability to represent them in our filesystem?
 353          */
 354         if (ia_valid & ATTR_ATIME)
 355                 inode->i_atime = attr->ia_atime;
 356         if (ia_valid & ATTR_CTIME)
 357                 inode->i_ctime = attr->ia_ctime;
 358         if (ia_valid & ATTR_MODE) {
 359                 ADFS_I(inode)->attr = adfs_mode2atts(sb, inode);
 360                 inode->i_mode = adfs_atts2mode(sb, inode);
 361         }
 362
 363         /*
 364          * FIXME: should we be marking this inode dirty even if
 365          * we don't have any metadata to write back?
 366          */
 367         if (ia_valid & (ATTR_SIZE | ATTR_MTIME | ATTR_MODE))
 368                 mark_inode_dirty(inode);
 369 out:
 370         unlock_kernel();
 371         return error;
 372 }
 373
 374 /*
 375  * write an existing inode back to the directory, and therefore the disk.
 376  * The adfs-specific inode data has already been updated by
 377  * adfs_notify_change()
 378  */
 379 int adfs_write_inode(struct inode *inode, int unused)
 380 {
 381         struct super_block *sb = inode->i_sb;
 382         struct object_info obj;
 383         int ret;
 384
 385         lock_kernel();
 386         obj.file_id     = inode->i_ino;
 387         obj.name_len    = 0;
 388         obj.parent_id   = ADFS_I(inode)->parent_id;
 389         obj.loadaddr    = ADFS_I(inode)->loadaddr;
 390         obj.execaddr    = ADFS_I(inode)->execaddr;
 391         obj.attr        = ADFS_I(inode)->attr;
 392         obj.size        = inode->i_size;
 393
 394         ret = adfs_dir_update(sb, &obj);
 395         unlock_kernel();
 396         return ret;
 397 }
 398 MODULE_LICENSE("GPL");