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/buffer_head.h> 11 #include <linux/writeback.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 (!create) { 23 if (block >= inode->i_blocks) 24 goto abort_toobig; 25 26 block = __adfs_block_map(inode->i_sb, inode->i_ino, block); 27 if (block) 28 map_bh(bh, inode->i_sb, block); 29 return 0; 30 } 31 /* don't support allocation of blocks yet */ 32 return -EIO; 33 34 abort_toobig: 35 return 0; 36 } 37 38 static int adfs_writepage(struct page *page, struct writeback_control *wbc) 39 { 40 return block_write_full_page(page, adfs_get_block, wbc); 41 } 42 43 static int adfs_readpage(struct file *file, struct page *page) 44 { 45 return block_read_full_page(page, adfs_get_block); 46 } 47 48 static int adfs_write_begin(struct file *file, struct address_space *mapping, 49 loff_t pos, unsigned len, unsigned flags, 50 struct page **pagep, void **fsdata) 51 { 52 int ret; 53 54 *pagep = NULL; 55 ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata, 56 adfs_get_block, 57 &ADFS_I(mapping->host)->mmu_private); 58 if (unlikely(ret)) { 59 loff_t isize = mapping->host->i_size; 60 if (pos + len > isize) 61 vmtruncate(mapping->host, isize); 62 } 63 64 return ret; 65 } 66 67 static sector_t _adfs_bmap(struct address_space *mapping, sector_t block) 68 { 69 return generic_block_bmap(mapping, block, adfs_get_block); 70 } 71 72 static const struct address_space_operations adfs_aops = { 73 .readpage = adfs_readpage, 74 .writepage = adfs_writepage, 75 .sync_page = block_sync_page, 76 .write_begin = adfs_write_begin, 77 .write_end = generic_write_end, 78 .bmap = _adfs_bmap 79 }; 80 81 static inline unsigned int 82 adfs_filetype(struct inode *inode) 83 { 84 unsigned int type; 85 86 if (ADFS_I(inode)->stamped) 87 type = (ADFS_I(inode)->loadaddr >> 8) & 0xfff; 88 else 89 type = (unsigned int) -1; 90 91 return type; 92 } 93 94 /* 95 * Convert ADFS attributes and filetype to Linux permission. 96 */ 97 static umode_t 98 adfs_atts2mode(struct super_block *sb, struct inode *inode) 99 { 100 unsigned int filetype, attr = ADFS_I(inode)->attr; 101 umode_t mode, rmask; 102 struct adfs_sb_info *asb = ADFS_SB(sb); 103 104 if (attr & ADFS_NDA_DIRECTORY) { 105 mode = S_IRUGO & asb->s_owner_mask; 106 return S_IFDIR | S_IXUGO | mode; 107 } 108 109 filetype = adfs_filetype(inode); 110 111 switch (filetype) { 112 case 0xfc0: /* LinkFS */ 113 return S_IFLNK|S_IRWXUGO; 114 115 case 0xfe6: /* UnixExec */ 116 rmask = S_IRUGO | S_IXUGO; 117 break; 118 119 default: 120 rmask = S_IRUGO; 121 } 122 123 mode = S_IFREG; 124 125 if (attr & ADFS_NDA_OWNER_READ) 126 mode |= rmask & asb->s_owner_mask; 127 128 if (attr & ADFS_NDA_OWNER_WRITE) 129 mode |= S_IWUGO & asb->s_owner_mask; 130 131 if (attr & ADFS_NDA_PUBLIC_READ) 132 mode |= rmask & asb->s_other_mask; 133 134 if (attr & ADFS_NDA_PUBLIC_WRITE) 135 mode |= S_IWUGO & asb->s_other_mask; 136 return mode; 137 } 138 139 /* 140 * Convert Linux permission to ADFS attribute. We try to do the reverse 141 * of atts2mode, but there is not a 1:1 translation. 142 */ 143 static int 144 adfs_mode2atts(struct super_block *sb, struct inode *inode) 145 { 146 umode_t mode; 147 int attr; 148 struct adfs_sb_info *asb = ADFS_SB(sb); 149 150 /* FIXME: should we be able to alter a link? */ 151 if (S_ISLNK(inode->i_mode)) 152 return ADFS_I(inode)->attr; 153 154 if (S_ISDIR(inode->i_mode)) 155 attr = ADFS_NDA_DIRECTORY; 156 else 157 attr = 0; 158 159 mode = inode->i_mode & asb->s_owner_mask; 160 if (mode & S_IRUGO) 161 attr |= ADFS_NDA_OWNER_READ; 162 if (mode & S_IWUGO) 163 attr |= ADFS_NDA_OWNER_WRITE; 164 165 mode = inode->i_mode & asb->s_other_mask; 166 mode &= ~asb->s_owner_mask; 167 if (mode & S_IRUGO) 168 attr |= ADFS_NDA_PUBLIC_READ; 169 if (mode & S_IWUGO) 170 attr |= ADFS_NDA_PUBLIC_WRITE; 171 172 return attr; 173 } 174 175 /* 176 * Convert an ADFS time to Unix time. ADFS has a 40-bit centi-second time 177 * referenced to 1 Jan 1900 (til 2248) 178 */ 179 static void 180 adfs_adfs2unix_time(struct timespec *tv, struct inode *inode) 181 { 182 unsigned int high, low; 183 184 if (ADFS_I(inode)->stamped == 0) 185 goto cur_time; 186 187 high = ADFS_I(inode)->loadaddr << 24; 188 low = ADFS_I(inode)->execaddr; 189 190 high |= low >> 8; 191 low &= 255; 192 193 /* Files dated pre 01 Jan 1970 00:00:00. */ 194 if (high < 0x336e996a) 195 goto too_early; 196 197 /* Files dated post 18 Jan 2038 03:14:05. */ 198 if (high >= 0x656e9969) 199 goto too_late; 200 201 /* discard 2208988800 (0x336e996a00) seconds of time */ 202 high -= 0x336e996a; 203 204 /* convert 40-bit centi-seconds to 32-bit seconds */ 205 tv->tv_sec = (((high % 100) << 8) + low) / 100 + (high / 100 << 8); 206 tv->tv_nsec = 0; 207 return; 208 209 cur_time: 210 *tv = CURRENT_TIME_SEC; 211 return; 212 213 too_early: 214 tv->tv_sec = tv->tv_nsec = 0; 215 return; 216 217 too_late: 218 tv->tv_sec = 0x7ffffffd; 219 tv->tv_nsec = 0; 220 return; 221 } 222 223 /* 224 * Convert an Unix time to ADFS time. We only do this if the entry has a 225 * time/date stamp already. 226 */ 227 static void 228 adfs_unix2adfs_time(struct inode *inode, unsigned int secs) 229 { 230 unsigned int high, low; 231 232 if (ADFS_I(inode)->stamped) { 233 /* convert 32-bit seconds to 40-bit centi-seconds */ 234 low = (secs & 255) * 100; 235 high = (secs / 256) * 100 + (low >> 8) + 0x336e996a; 236 237 ADFS_I(inode)->loadaddr = (high >> 24) | 238 (ADFS_I(inode)->loadaddr & ~0xff); 239 ADFS_I(inode)->execaddr = (low & 255) | (high << 8); 240 } 241 } 242 243 /* 244 * Fill in the inode information from the object information. 245 * 246 * Note that this is an inode-less filesystem, so we can't use the inode 247 * number to reference the metadata on the media. Instead, we use the 248 * inode number to hold the object ID, which in turn will tell us where 249 * the data is held. We also save the parent object ID, and with these 250 * two, we can locate the metadata. 251 * 252 * This does mean that we rely on an objects parent remaining the same at 253 * all times - we cannot cope with a cross-directory rename (yet). 254 */ 255 struct inode * 256 adfs_iget(struct super_block *sb, struct object_info *obj) 257 { 258 struct inode *inode; 259 260 inode = new_inode(sb); 261 if (!inode) 262 goto out; 263 264 inode->i_uid = ADFS_SB(sb)->s_uid; 265 inode->i_gid = ADFS_SB(sb)->s_gid; 266 inode->i_ino = obj->file_id; 267 inode->i_size = obj->size; 268 inode->i_nlink = 2; 269 inode->i_blocks = (inode->i_size + sb->s_blocksize - 1) >> 270 sb->s_blocksize_bits; 271 272 /* 273 * we need to save the parent directory ID so that 274 * write_inode can update the directory information 275 * for this file. This will need special handling 276 * for cross-directory renames. 277 */ 278 ADFS_I(inode)->parent_id = obj->parent_id; 279 ADFS_I(inode)->loadaddr = obj->loadaddr; 280 ADFS_I(inode)->execaddr = obj->execaddr; 281 ADFS_I(inode)->attr = obj->attr; 282 ADFS_I(inode)->stamped = ((obj->loadaddr & 0xfff00000) == 0xfff00000); 283 284 inode->i_mode = adfs_atts2mode(sb, inode); 285 adfs_adfs2unix_time(&inode->i_mtime, inode); 286 inode->i_atime = inode->i_mtime; 287 inode->i_ctime = inode->i_mtime; 288 289 if (S_ISDIR(inode->i_mode)) { 290 inode->i_op = &adfs_dir_inode_operations; 291 inode->i_fop = &adfs_dir_operations; 292 } else if (S_ISREG(inode->i_mode)) { 293 inode->i_op = &adfs_file_inode_operations; 294 inode->i_fop = &adfs_file_operations; 295 inode->i_mapping->a_ops = &adfs_aops; 296 ADFS_I(inode)->mmu_private = inode->i_size; 297 } 298 299 insert_inode_hash(inode); 300 301 out: 302 return inode; 303 } 304 305 /* 306 * Validate and convert a changed access mode/time to their ADFS equivalents. 307 * adfs_write_inode will actually write the information back to the directory 308 * later. 309 */ 310 int 311 adfs_notify_change(struct dentry *dentry, struct iattr *attr) 312 { 313 struct inode *inode = dentry->d_inode; 314 struct super_block *sb = inode->i_sb; 315 unsigned int ia_valid = attr->ia_valid; 316 int error; 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 /* XXX: this is missing some actual on-disk truncation.. */ 332 if (ia_valid & ATTR_SIZE) 333 truncate_setsize(inode, attr->ia_size); 334 335 if (ia_valid & ATTR_MTIME) { 336 inode->i_mtime = attr->ia_mtime; 337 adfs_unix2adfs_time(inode, attr->ia_mtime.tv_sec); 338 } 339 /* 340 * FIXME: should we make these == to i_mtime since we don't 341 * have the ability to represent them in our filesystem? 342 */ 343 if (ia_valid & ATTR_ATIME) 344 inode->i_atime = attr->ia_atime; 345 if (ia_valid & ATTR_CTIME) 346 inode->i_ctime = attr->ia_ctime; 347 if (ia_valid & ATTR_MODE) { 348 ADFS_I(inode)->attr = adfs_mode2atts(sb, inode); 349 inode->i_mode = adfs_atts2mode(sb, inode); 350 } 351 352 /* 353 * FIXME: should we be marking this inode dirty even if 354 * we don't have any metadata to write back? 355 */ 356 if (ia_valid & (ATTR_SIZE | ATTR_MTIME | ATTR_MODE)) 357 mark_inode_dirty(inode); 358 out: 359 return error; 360 } 361 362 /* 363 * write an existing inode back to the directory, and therefore the disk. 364 * The adfs-specific inode data has already been updated by 365 * adfs_notify_change() 366 */ 367 int adfs_write_inode(struct inode *inode, struct writeback_control *wbc) 368 { 369 struct super_block *sb = inode->i_sb; 370 struct object_info obj; 371 int ret; 372 373 obj.file_id = inode->i_ino; 374 obj.name_len = 0; 375 obj.parent_id = ADFS_I(inode)->parent_id; 376 obj.loadaddr = ADFS_I(inode)->loadaddr; 377 obj.execaddr = ADFS_I(inode)->execaddr; 378 obj.attr = ADFS_I(inode)->attr; 379 obj.size = inode->i_size; 380 381 ret = adfs_dir_update(sb, &obj, wbc->sync_mode == WB_SYNC_ALL); 382 return ret; 383 } 384