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