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 <linux/writeback.h> 13 #include "adfs.h" 14 15 /* 16 * Lookup/Create a block at offset 'block' into 'inode'. We currently do 17 * not support creation of new blocks, so we return -EIO for this case. 18 */ 19 static int 20 adfs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh, 21 int create) 22 { 23 if (!create) { 24 if (block >= inode->i_blocks) 25 goto abort_toobig; 26 27 block = __adfs_block_map(inode->i_sb, inode->i_ino, block); 28 if (block) 29 map_bh(bh, inode->i_sb, block); 30 return 0; 31 } 32 /* don't support allocation of blocks yet */ 33 return -EIO; 34 35 abort_toobig: 36 return 0; 37 } 38 39 static int adfs_writepage(struct page *page, struct writeback_control *wbc) 40 { 41 return block_write_full_page(page, adfs_get_block, wbc); 42 } 43 44 static int adfs_readpage(struct file *file, struct page *page) 45 { 46 return block_read_full_page(page, adfs_get_block); 47 } 48 49 static int adfs_write_begin(struct file *file, struct address_space *mapping, 50 loff_t pos, unsigned len, unsigned flags, 51 struct page **pagep, void **fsdata) 52 { 53 int ret; 54 55 *pagep = NULL; 56 ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata, 57 adfs_get_block, 58 &ADFS_I(mapping->host)->mmu_private); 59 if (unlikely(ret)) { 60 loff_t isize = mapping->host->i_size; 61 if (pos + len > isize) 62 vmtruncate(mapping->host, isize); 63 } 64 65 return ret; 66 } 67 68 static sector_t _adfs_bmap(struct address_space *mapping, sector_t block) 69 { 70 return generic_block_bmap(mapping, block, adfs_get_block); 71 } 72 73 static const struct address_space_operations adfs_aops = { 74 .readpage = adfs_readpage, 75 .writepage = adfs_writepage, 76 .sync_page = block_sync_page, 77 .write_begin = adfs_write_begin, 78 .write_end = generic_write_end, 79 .bmap = _adfs_bmap 80 }; 81 82 static inline unsigned int 83 adfs_filetype(struct inode *inode) 84 { 85 unsigned int type; 86 87 if (ADFS_I(inode)->stamped) 88 type = (ADFS_I(inode)->loadaddr >> 8) & 0xfff; 89 else 90 type = (unsigned int) -1; 91 92 return type; 93 } 94 95 /* 96 * Convert ADFS attributes and filetype to Linux permission. 97 */ 98 static umode_t 99 adfs_atts2mode(struct super_block *sb, struct inode *inode) 100 { 101 unsigned int filetype, attr = ADFS_I(inode)->attr; 102 umode_t mode, rmask; 103 struct adfs_sb_info *asb = ADFS_SB(sb); 104 105 if (attr & ADFS_NDA_DIRECTORY) { 106 mode = S_IRUGO & asb->s_owner_mask; 107 return S_IFDIR | S_IXUGO | mode; 108 } 109 110 filetype = adfs_filetype(inode); 111 112 switch (filetype) { 113 case 0xfc0: /* LinkFS */ 114 return S_IFLNK|S_IRWXUGO; 115 116 case 0xfe6: /* UnixExec */ 117 rmask = S_IRUGO | S_IXUGO; 118 break; 119 120 default: 121 rmask = S_IRUGO; 122 } 123 124 mode = S_IFREG; 125 126 if (attr & ADFS_NDA_OWNER_READ) 127 mode |= rmask & asb->s_owner_mask; 128 129 if (attr & ADFS_NDA_OWNER_WRITE) 130 mode |= S_IWUGO & asb->s_owner_mask; 131 132 if (attr & ADFS_NDA_PUBLIC_READ) 133 mode |= rmask & asb->s_other_mask; 134 135 if (attr & ADFS_NDA_PUBLIC_WRITE) 136 mode |= S_IWUGO & asb->s_other_mask; 137 return mode; 138 } 139 140 /* 141 * Convert Linux permission to ADFS attribute. We try to do the reverse 142 * of atts2mode, but there is not a 1:1 translation. 143 */ 144 static int 145 adfs_mode2atts(struct super_block *sb, struct inode *inode) 146 { 147 umode_t mode; 148 int attr; 149 struct adfs_sb_info *asb = ADFS_SB(sb); 150 151 /* FIXME: should we be able to alter a link? */ 152 if (S_ISLNK(inode->i_mode)) 153 return ADFS_I(inode)->attr; 154 155 if (S_ISDIR(inode->i_mode)) 156 attr = ADFS_NDA_DIRECTORY; 157 else 158 attr = 0; 159 160 mode = inode->i_mode & asb->s_owner_mask; 161 if (mode & S_IRUGO) 162 attr |= ADFS_NDA_OWNER_READ; 163 if (mode & S_IWUGO) 164 attr |= ADFS_NDA_OWNER_WRITE; 165 166 mode = inode->i_mode & asb->s_other_mask; 167 mode &= ~asb->s_owner_mask; 168 if (mode & S_IRUGO) 169 attr |= ADFS_NDA_PUBLIC_READ; 170 if (mode & S_IWUGO) 171 attr |= ADFS_NDA_PUBLIC_WRITE; 172 173 return attr; 174 } 175 176 /* 177 * Convert an ADFS time to Unix time. ADFS has a 40-bit centi-second time 178 * referenced to 1 Jan 1900 (til 2248) 179 */ 180 static void 181 adfs_adfs2unix_time(struct timespec *tv, struct inode *inode) 182 { 183 unsigned int high, low; 184 185 if (ADFS_I(inode)->stamped == 0) 186 goto cur_time; 187 188 high = ADFS_I(inode)->loadaddr << 24; 189 low = ADFS_I(inode)->execaddr; 190 191 high |= low >> 8; 192 low &= 255; 193 194 /* Files dated pre 01 Jan 1970 00:00:00. */ 195 if (high < 0x336e996a) 196 goto too_early; 197 198 /* Files dated post 18 Jan 2038 03:14:05. */ 199 if (high >= 0x656e9969) 200 goto too_late; 201 202 /* discard 2208988800 (0x336e996a00) seconds of time */ 203 high -= 0x336e996a; 204 205 /* convert 40-bit centi-seconds to 32-bit seconds */ 206 tv->tv_sec = (((high % 100) << 8) + low) / 100 + (high / 100 << 8); 207 tv->tv_nsec = 0; 208 return; 209 210 cur_time: 211 *tv = CURRENT_TIME_SEC; 212 return; 213 214 too_early: 215 tv->tv_sec = tv->tv_nsec = 0; 216 return; 217 218 too_late: 219 tv->tv_sec = 0x7ffffffd; 220 tv->tv_nsec = 0; 221 return; 222 } 223 224 /* 225 * Convert an Unix time to ADFS time. We only do this if the entry has a 226 * time/date stamp already. 227 */ 228 static void 229 adfs_unix2adfs_time(struct inode *inode, unsigned int secs) 230 { 231 unsigned int high, low; 232 233 if (ADFS_I(inode)->stamped) { 234 /* convert 32-bit seconds to 40-bit centi-seconds */ 235 low = (secs & 255) * 100; 236 high = (secs / 256) * 100 + (low >> 8) + 0x336e996a; 237 238 ADFS_I(inode)->loadaddr = (high >> 24) | 239 (ADFS_I(inode)->loadaddr & ~0xff); 240 ADFS_I(inode)->execaddr = (low & 255) | (high << 8); 241 } 242 } 243 244 /* 245 * Fill in the inode information from the object information. 246 * 247 * Note that this is an inode-less filesystem, so we can't use the inode 248 * number to reference the metadata on the media. Instead, we use the 249 * inode number to hold the object ID, which in turn will tell us where 250 * the data is held. We also save the parent object ID, and with these 251 * two, we can locate the metadata. 252 * 253 * This does mean that we rely on an objects parent remaining the same at 254 * all times - we cannot cope with a cross-directory rename (yet). 255 */ 256 struct inode * 257 adfs_iget(struct super_block *sb, struct object_info *obj) 258 { 259 struct inode *inode; 260 261 inode = new_inode(sb); 262 if (!inode) 263 goto out; 264 265 inode->i_uid = ADFS_SB(sb)->s_uid; 266 inode->i_gid = ADFS_SB(sb)->s_gid; 267 inode->i_ino = obj->file_id; 268 inode->i_size = obj->size; 269 inode->i_nlink = 2; 270 inode->i_blocks = (inode->i_size + sb->s_blocksize - 1) >> 271 sb->s_blocksize_bits; 272 273 /* 274 * we need to save the parent directory ID so that 275 * write_inode can update the directory information 276 * for this file. This will need special handling 277 * for cross-directory renames. 278 */ 279 ADFS_I(inode)->parent_id = obj->parent_id; 280 ADFS_I(inode)->loadaddr = obj->loadaddr; 281 ADFS_I(inode)->execaddr = obj->execaddr; 282 ADFS_I(inode)->attr = obj->attr; 283 ADFS_I(inode)->stamped = ((obj->loadaddr & 0xfff00000) == 0xfff00000); 284 285 inode->i_mode = adfs_atts2mode(sb, inode); 286 adfs_adfs2unix_time(&inode->i_mtime, inode); 287 inode->i_atime = inode->i_mtime; 288 inode->i_ctime = inode->i_mtime; 289 290 if (S_ISDIR(inode->i_mode)) { 291 inode->i_op = &adfs_dir_inode_operations; 292 inode->i_fop = &adfs_dir_operations; 293 } else if (S_ISREG(inode->i_mode)) { 294 inode->i_op = &adfs_file_inode_operations; 295 inode->i_fop = &adfs_file_operations; 296 inode->i_mapping->a_ops = &adfs_aops; 297 ADFS_I(inode)->mmu_private = inode->i_size; 298 } 299 300 insert_inode_hash(inode); 301 302 out: 303 return inode; 304 } 305 306 /* 307 * Validate and convert a changed access mode/time to their ADFS equivalents. 308 * adfs_write_inode will actually write the information back to the directory 309 * later. 310 */ 311 int 312 adfs_notify_change(struct dentry *dentry, struct iattr *attr) 313 { 314 struct inode *inode = dentry->d_inode; 315 struct super_block *sb = inode->i_sb; 316 unsigned int ia_valid = attr->ia_valid; 317 int error; 318 319 lock_kernel(); 320 321 error = inode_change_ok(inode, attr); 322 323 /* 324 * we can't change the UID or GID of any file - 325 * we have a global UID/GID in the superblock 326 */ 327 if ((ia_valid & ATTR_UID && attr->ia_uid != ADFS_SB(sb)->s_uid) || 328 (ia_valid & ATTR_GID && attr->ia_gid != ADFS_SB(sb)->s_gid)) 329 error = -EPERM; 330 331 if (error) 332 goto out; 333 334 /* XXX: this is missing some actual on-disk truncation.. */ 335 if (ia_valid & ATTR_SIZE) 336 truncate_setsize(inode, attr->ia_size); 337 338 if (ia_valid & ATTR_MTIME) { 339 inode->i_mtime = attr->ia_mtime; 340 adfs_unix2adfs_time(inode, attr->ia_mtime.tv_sec); 341 } 342 /* 343 * FIXME: should we make these == to i_mtime since we don't 344 * have the ability to represent them in our filesystem? 345 */ 346 if (ia_valid & ATTR_ATIME) 347 inode->i_atime = attr->ia_atime; 348 if (ia_valid & ATTR_CTIME) 349 inode->i_ctime = attr->ia_ctime; 350 if (ia_valid & ATTR_MODE) { 351 ADFS_I(inode)->attr = adfs_mode2atts(sb, inode); 352 inode->i_mode = adfs_atts2mode(sb, inode); 353 } 354 355 /* 356 * FIXME: should we be marking this inode dirty even if 357 * we don't have any metadata to write back? 358 */ 359 if (ia_valid & (ATTR_SIZE | ATTR_MTIME | ATTR_MODE)) 360 mark_inode_dirty(inode); 361 out: 362 unlock_kernel(); 363 return error; 364 } 365 366 /* 367 * write an existing inode back to the directory, and therefore the disk. 368 * The adfs-specific inode data has already been updated by 369 * adfs_notify_change() 370 */ 371 int adfs_write_inode(struct inode *inode, struct writeback_control *wbc) 372 { 373 struct super_block *sb = inode->i_sb; 374 struct object_info obj; 375 int ret; 376 377 lock_kernel(); 378 obj.file_id = inode->i_ino; 379 obj.name_len = 0; 380 obj.parent_id = ADFS_I(inode)->parent_id; 381 obj.loadaddr = ADFS_I(inode)->loadaddr; 382 obj.execaddr = ADFS_I(inode)->execaddr; 383 obj.attr = ADFS_I(inode)->attr; 384 obj.size = inode->i_size; 385 386 ret = adfs_dir_update(sb, &obj, wbc->sync_mode == WB_SYNC_ALL); 387 unlock_kernel(); 388 return ret; 389 } 390