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