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 } 389