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_blksize = PAGE_SIZE; 273 inode->i_blocks = (inode->i_size + sb->s_blocksize - 1) >> 274 sb->s_blocksize_bits; 275 276 /* 277 * we need to save the parent directory ID so that 278 * write_inode can update the directory information 279 * for this file. This will need special handling 280 * for cross-directory renames. 281 */ 282 ADFS_I(inode)->parent_id = obj->parent_id; 283 ADFS_I(inode)->loadaddr = obj->loadaddr; 284 ADFS_I(inode)->execaddr = obj->execaddr; 285 ADFS_I(inode)->attr = obj->attr; 286 ADFS_I(inode)->stamped = ((obj->loadaddr & 0xfff00000) == 0xfff00000); 287 288 inode->i_mode = adfs_atts2mode(sb, inode); 289 adfs_adfs2unix_time(&inode->i_mtime, inode); 290 inode->i_atime = inode->i_mtime; 291 inode->i_ctime = inode->i_mtime; 292 293 if (S_ISDIR(inode->i_mode)) { 294 inode->i_op = &adfs_dir_inode_operations; 295 inode->i_fop = &adfs_dir_operations; 296 } else if (S_ISREG(inode->i_mode)) { 297 inode->i_op = &adfs_file_inode_operations; 298 inode->i_fop = &adfs_file_operations; 299 inode->i_mapping->a_ops = &adfs_aops; 300 ADFS_I(inode)->mmu_private = inode->i_size; 301 } 302 303 insert_inode_hash(inode); 304 305 out: 306 return inode; 307 } 308 309 /* 310 * Validate and convert a changed access mode/time to their ADFS equivalents. 311 * adfs_write_inode will actually write the information back to the directory 312 * later. 313 */ 314 int 315 adfs_notify_change(struct dentry *dentry, struct iattr *attr) 316 { 317 struct inode *inode = dentry->d_inode; 318 struct super_block *sb = inode->i_sb; 319 unsigned int ia_valid = attr->ia_valid; 320 int error; 321 322 lock_kernel(); 323 324 error = inode_change_ok(inode, attr); 325 326 /* 327 * we can't change the UID or GID of any file - 328 * we have a global UID/GID in the superblock 329 */ 330 if ((ia_valid & ATTR_UID && attr->ia_uid != ADFS_SB(sb)->s_uid) || 331 (ia_valid & ATTR_GID && attr->ia_gid != ADFS_SB(sb)->s_gid)) 332 error = -EPERM; 333 334 if (error) 335 goto out; 336 337 if (ia_valid & ATTR_SIZE) 338 error = vmtruncate(inode, attr->ia_size); 339 340 if (error) 341 goto out; 342 343 if (ia_valid & ATTR_MTIME) { 344 inode->i_mtime = attr->ia_mtime; 345 adfs_unix2adfs_time(inode, attr->ia_mtime.tv_sec); 346 } 347 /* 348 * FIXME: should we make these == to i_mtime since we don't 349 * have the ability to represent them in our filesystem? 350 */ 351 if (ia_valid & ATTR_ATIME) 352 inode->i_atime = attr->ia_atime; 353 if (ia_valid & ATTR_CTIME) 354 inode->i_ctime = attr->ia_ctime; 355 if (ia_valid & ATTR_MODE) { 356 ADFS_I(inode)->attr = adfs_mode2atts(sb, inode); 357 inode->i_mode = adfs_atts2mode(sb, inode); 358 } 359 360 /* 361 * FIXME: should we be marking this inode dirty even if 362 * we don't have any metadata to write back? 363 */ 364 if (ia_valid & (ATTR_SIZE | ATTR_MTIME | ATTR_MODE)) 365 mark_inode_dirty(inode); 366 out: 367 unlock_kernel(); 368 return error; 369 } 370 371 /* 372 * write an existing inode back to the directory, and therefore the disk. 373 * The adfs-specific inode data has already been updated by 374 * adfs_notify_change() 375 */ 376 int adfs_write_inode(struct inode *inode, int unused) 377 { 378 struct super_block *sb = inode->i_sb; 379 struct object_info obj; 380 int ret; 381 382 lock_kernel(); 383 obj.file_id = inode->i_ino; 384 obj.name_len = 0; 385 obj.parent_id = ADFS_I(inode)->parent_id; 386 obj.loadaddr = ADFS_I(inode)->loadaddr; 387 obj.execaddr = ADFS_I(inode)->execaddr; 388 obj.attr = ADFS_I(inode)->attr; 389 obj.size = inode->i_size; 390 391 ret = adfs_dir_update(sb, &obj); 392 unlock_kernel(); 393 return ret; 394 } 395 MODULE_LICENSE("GPL"); 396