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"); 399