11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * inode.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Copyright (c) 1999 Al Smith 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * Portions derived from work (c) 1995,1996 Christian Vogelgsang, 71da177e4SLinus Torvalds * and from work (c) 1998 Mike Shaver. 81da177e4SLinus Torvalds */ 91da177e4SLinus Torvalds 101da177e4SLinus Torvalds #include <linux/efs_fs.h> 111da177e4SLinus Torvalds #include <linux/efs_fs_sb.h> 121da177e4SLinus Torvalds #include <linux/buffer_head.h> 131da177e4SLinus Torvalds #include <linux/module.h> 141da177e4SLinus Torvalds #include <linux/fs.h> 151da177e4SLinus Torvalds 161da177e4SLinus Torvalds static int efs_readpage(struct file *file, struct page *page) 171da177e4SLinus Torvalds { 181da177e4SLinus Torvalds return block_read_full_page(page,efs_get_block); 191da177e4SLinus Torvalds } 201da177e4SLinus Torvalds static sector_t _efs_bmap(struct address_space *mapping, sector_t block) 211da177e4SLinus Torvalds { 221da177e4SLinus Torvalds return generic_block_bmap(mapping,block,efs_get_block); 231da177e4SLinus Torvalds } 24f5e54d6eSChristoph Hellwig static const struct address_space_operations efs_aops = { 251da177e4SLinus Torvalds .readpage = efs_readpage, 261da177e4SLinus Torvalds .sync_page = block_sync_page, 271da177e4SLinus Torvalds .bmap = _efs_bmap 281da177e4SLinus Torvalds }; 291da177e4SLinus Torvalds 301da177e4SLinus Torvalds static inline void extent_copy(efs_extent *src, efs_extent *dst) { 311da177e4SLinus Torvalds /* 321da177e4SLinus Torvalds * this is slightly evil. it doesn't just copy 331da177e4SLinus Torvalds * efs_extent from src to dst, it also mangles 341da177e4SLinus Torvalds * the bits so that dst ends up in cpu byte-order. 351da177e4SLinus Torvalds */ 361da177e4SLinus Torvalds 371da177e4SLinus Torvalds dst->cooked.ex_magic = (unsigned int) src->raw[0]; 381da177e4SLinus Torvalds dst->cooked.ex_bn = ((unsigned int) src->raw[1] << 16) | 391da177e4SLinus Torvalds ((unsigned int) src->raw[2] << 8) | 401da177e4SLinus Torvalds ((unsigned int) src->raw[3] << 0); 411da177e4SLinus Torvalds dst->cooked.ex_length = (unsigned int) src->raw[4]; 421da177e4SLinus Torvalds dst->cooked.ex_offset = ((unsigned int) src->raw[5] << 16) | 431da177e4SLinus Torvalds ((unsigned int) src->raw[6] << 8) | 441da177e4SLinus Torvalds ((unsigned int) src->raw[7] << 0); 451da177e4SLinus Torvalds return; 461da177e4SLinus Torvalds } 471da177e4SLinus Torvalds 481da177e4SLinus Torvalds void efs_read_inode(struct inode *inode) 491da177e4SLinus Torvalds { 501da177e4SLinus Torvalds int i, inode_index; 511da177e4SLinus Torvalds dev_t device; 521da177e4SLinus Torvalds u32 rdev; 531da177e4SLinus Torvalds struct buffer_head *bh; 541da177e4SLinus Torvalds struct efs_sb_info *sb = SUPER_INFO(inode->i_sb); 551da177e4SLinus Torvalds struct efs_inode_info *in = INODE_INFO(inode); 561da177e4SLinus Torvalds efs_block_t block, offset; 571da177e4SLinus Torvalds struct efs_dinode *efs_inode; 581da177e4SLinus Torvalds 591da177e4SLinus Torvalds /* 601da177e4SLinus Torvalds ** EFS layout: 611da177e4SLinus Torvalds ** 621da177e4SLinus Torvalds ** | cylinder group | cylinder group | cylinder group ..etc 631da177e4SLinus Torvalds ** |inodes|data |inodes|data |inodes|data ..etc 641da177e4SLinus Torvalds ** 651da177e4SLinus Torvalds ** work out the inode block index, (considering initially that the 661da177e4SLinus Torvalds ** inodes are stored as consecutive blocks). then work out the block 671da177e4SLinus Torvalds ** number of that inode given the above layout, and finally the 681da177e4SLinus Torvalds ** offset of the inode within that block. 691da177e4SLinus Torvalds */ 701da177e4SLinus Torvalds 711da177e4SLinus Torvalds inode_index = inode->i_ino / 721da177e4SLinus Torvalds (EFS_BLOCKSIZE / sizeof(struct efs_dinode)); 731da177e4SLinus Torvalds 741da177e4SLinus Torvalds block = sb->fs_start + sb->first_block + 751da177e4SLinus Torvalds (sb->group_size * (inode_index / sb->inode_blocks)) + 761da177e4SLinus Torvalds (inode_index % sb->inode_blocks); 771da177e4SLinus Torvalds 781da177e4SLinus Torvalds offset = (inode->i_ino % 791da177e4SLinus Torvalds (EFS_BLOCKSIZE / sizeof(struct efs_dinode))) * 801da177e4SLinus Torvalds sizeof(struct efs_dinode); 811da177e4SLinus Torvalds 821da177e4SLinus Torvalds bh = sb_bread(inode->i_sb, block); 831da177e4SLinus Torvalds if (!bh) { 841da177e4SLinus Torvalds printk(KERN_WARNING "EFS: bread() failed at block %d\n", block); 851da177e4SLinus Torvalds goto read_inode_error; 861da177e4SLinus Torvalds } 871da177e4SLinus Torvalds 881da177e4SLinus Torvalds efs_inode = (struct efs_dinode *) (bh->b_data + offset); 891da177e4SLinus Torvalds 901da177e4SLinus Torvalds inode->i_mode = be16_to_cpu(efs_inode->di_mode); 911da177e4SLinus Torvalds inode->i_nlink = be16_to_cpu(efs_inode->di_nlink); 921da177e4SLinus Torvalds inode->i_uid = (uid_t)be16_to_cpu(efs_inode->di_uid); 931da177e4SLinus Torvalds inode->i_gid = (gid_t)be16_to_cpu(efs_inode->di_gid); 941da177e4SLinus Torvalds inode->i_size = be32_to_cpu(efs_inode->di_size); 951da177e4SLinus Torvalds inode->i_atime.tv_sec = be32_to_cpu(efs_inode->di_atime); 961da177e4SLinus Torvalds inode->i_mtime.tv_sec = be32_to_cpu(efs_inode->di_mtime); 971da177e4SLinus Torvalds inode->i_ctime.tv_sec = be32_to_cpu(efs_inode->di_ctime); 981da177e4SLinus Torvalds inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0; 991da177e4SLinus Torvalds 1001da177e4SLinus Torvalds /* this is the number of blocks in the file */ 1011da177e4SLinus Torvalds if (inode->i_size == 0) { 1021da177e4SLinus Torvalds inode->i_blocks = 0; 1031da177e4SLinus Torvalds } else { 1041da177e4SLinus Torvalds inode->i_blocks = ((inode->i_size - 1) >> EFS_BLOCKSIZE_BITS) + 1; 1051da177e4SLinus Torvalds } 1061da177e4SLinus Torvalds 1071da177e4SLinus Torvalds rdev = be16_to_cpu(efs_inode->di_u.di_dev.odev); 1081da177e4SLinus Torvalds if (rdev == 0xffff) { 1091da177e4SLinus Torvalds rdev = be32_to_cpu(efs_inode->di_u.di_dev.ndev); 1101da177e4SLinus Torvalds if (sysv_major(rdev) > 0xfff) 1111da177e4SLinus Torvalds device = 0; 1121da177e4SLinus Torvalds else 1131da177e4SLinus Torvalds device = MKDEV(sysv_major(rdev), sysv_minor(rdev)); 1141da177e4SLinus Torvalds } else 1151da177e4SLinus Torvalds device = old_decode_dev(rdev); 1161da177e4SLinus Torvalds 1171da177e4SLinus Torvalds /* get the number of extents for this object */ 1181da177e4SLinus Torvalds in->numextents = be16_to_cpu(efs_inode->di_numextents); 1191da177e4SLinus Torvalds in->lastextent = 0; 1201da177e4SLinus Torvalds 1211da177e4SLinus Torvalds /* copy the extents contained within the inode to memory */ 1221da177e4SLinus Torvalds for(i = 0; i < EFS_DIRECTEXTENTS; i++) { 1231da177e4SLinus Torvalds extent_copy(&(efs_inode->di_u.di_extents[i]), &(in->extents[i])); 1241da177e4SLinus Torvalds if (i < in->numextents && in->extents[i].cooked.ex_magic != 0) { 1251da177e4SLinus Torvalds printk(KERN_WARNING "EFS: extent %d has bad magic number in inode %lu\n", i, inode->i_ino); 1261da177e4SLinus Torvalds brelse(bh); 1271da177e4SLinus Torvalds goto read_inode_error; 1281da177e4SLinus Torvalds } 1291da177e4SLinus Torvalds } 1301da177e4SLinus Torvalds 1311da177e4SLinus Torvalds brelse(bh); 1321da177e4SLinus Torvalds 1331da177e4SLinus Torvalds #ifdef DEBUG 1341da177e4SLinus Torvalds printk(KERN_DEBUG "EFS: read_inode(): inode %lu, extents %d, mode %o\n", 1351da177e4SLinus Torvalds inode->i_ino, in->numextents, inode->i_mode); 1361da177e4SLinus Torvalds #endif 1371da177e4SLinus Torvalds 1381da177e4SLinus Torvalds switch (inode->i_mode & S_IFMT) { 1391da177e4SLinus Torvalds case S_IFDIR: 1401da177e4SLinus Torvalds inode->i_op = &efs_dir_inode_operations; 1411da177e4SLinus Torvalds inode->i_fop = &efs_dir_operations; 1421da177e4SLinus Torvalds break; 1431da177e4SLinus Torvalds case S_IFREG: 1441da177e4SLinus Torvalds inode->i_fop = &generic_ro_fops; 1451da177e4SLinus Torvalds inode->i_data.a_ops = &efs_aops; 1461da177e4SLinus Torvalds break; 1471da177e4SLinus Torvalds case S_IFLNK: 1481da177e4SLinus Torvalds inode->i_op = &page_symlink_inode_operations; 1491da177e4SLinus Torvalds inode->i_data.a_ops = &efs_symlink_aops; 1501da177e4SLinus Torvalds break; 1511da177e4SLinus Torvalds case S_IFCHR: 1521da177e4SLinus Torvalds case S_IFBLK: 1531da177e4SLinus Torvalds case S_IFIFO: 1541da177e4SLinus Torvalds init_special_inode(inode, inode->i_mode, device); 1551da177e4SLinus Torvalds break; 1561da177e4SLinus Torvalds default: 1571da177e4SLinus Torvalds printk(KERN_WARNING "EFS: unsupported inode mode %o\n", inode->i_mode); 1581da177e4SLinus Torvalds goto read_inode_error; 1591da177e4SLinus Torvalds break; 1601da177e4SLinus Torvalds } 1611da177e4SLinus Torvalds 1621da177e4SLinus Torvalds return; 1631da177e4SLinus Torvalds 1641da177e4SLinus Torvalds read_inode_error: 1651da177e4SLinus Torvalds printk(KERN_WARNING "EFS: failed to read inode %lu\n", inode->i_ino); 1661da177e4SLinus Torvalds make_bad_inode(inode); 1671da177e4SLinus Torvalds 1681da177e4SLinus Torvalds return; 1691da177e4SLinus Torvalds } 1701da177e4SLinus Torvalds 1711da177e4SLinus Torvalds static inline efs_block_t 1721da177e4SLinus Torvalds efs_extent_check(efs_extent *ptr, efs_block_t block, struct efs_sb_info *sb) { 1731da177e4SLinus Torvalds efs_block_t start; 1741da177e4SLinus Torvalds efs_block_t length; 1751da177e4SLinus Torvalds efs_block_t offset; 1761da177e4SLinus Torvalds 1771da177e4SLinus Torvalds /* 1781da177e4SLinus Torvalds * given an extent and a logical block within a file, 1791da177e4SLinus Torvalds * can this block be found within this extent ? 1801da177e4SLinus Torvalds */ 1811da177e4SLinus Torvalds start = ptr->cooked.ex_bn; 1821da177e4SLinus Torvalds length = ptr->cooked.ex_length; 1831da177e4SLinus Torvalds offset = ptr->cooked.ex_offset; 1841da177e4SLinus Torvalds 1851da177e4SLinus Torvalds if ((block >= offset) && (block < offset+length)) { 1861da177e4SLinus Torvalds return(sb->fs_start + start + block - offset); 1871da177e4SLinus Torvalds } else { 1881da177e4SLinus Torvalds return 0; 1891da177e4SLinus Torvalds } 1901da177e4SLinus Torvalds } 1911da177e4SLinus Torvalds 1921da177e4SLinus Torvalds efs_block_t efs_map_block(struct inode *inode, efs_block_t block) { 1931da177e4SLinus Torvalds struct efs_sb_info *sb = SUPER_INFO(inode->i_sb); 1941da177e4SLinus Torvalds struct efs_inode_info *in = INODE_INFO(inode); 1951da177e4SLinus Torvalds struct buffer_head *bh = NULL; 1961da177e4SLinus Torvalds 1971da177e4SLinus Torvalds int cur, last, first = 1; 1981da177e4SLinus Torvalds int ibase, ioffset, dirext, direxts, indext, indexts; 1991da177e4SLinus Torvalds efs_block_t iblock, result = 0, lastblock = 0; 2001da177e4SLinus Torvalds efs_extent ext, *exts; 2011da177e4SLinus Torvalds 2021da177e4SLinus Torvalds last = in->lastextent; 2031da177e4SLinus Torvalds 2041da177e4SLinus Torvalds if (in->numextents <= EFS_DIRECTEXTENTS) { 2051da177e4SLinus Torvalds /* first check the last extent we returned */ 2061da177e4SLinus Torvalds if ((result = efs_extent_check(&in->extents[last], block, sb))) 2071da177e4SLinus Torvalds return result; 2081da177e4SLinus Torvalds 2091da177e4SLinus Torvalds /* if we only have one extent then nothing can be found */ 2101da177e4SLinus Torvalds if (in->numextents == 1) { 2111da177e4SLinus Torvalds printk(KERN_ERR "EFS: map_block() failed to map (1 extent)\n"); 2121da177e4SLinus Torvalds return 0; 2131da177e4SLinus Torvalds } 2141da177e4SLinus Torvalds 2151da177e4SLinus Torvalds direxts = in->numextents; 2161da177e4SLinus Torvalds 2171da177e4SLinus Torvalds /* 2181da177e4SLinus Torvalds * check the stored extents in the inode 2191da177e4SLinus Torvalds * start with next extent and check forwards 2201da177e4SLinus Torvalds */ 2211da177e4SLinus Torvalds for(dirext = 1; dirext < direxts; dirext++) { 2221da177e4SLinus Torvalds cur = (last + dirext) % in->numextents; 2231da177e4SLinus Torvalds if ((result = efs_extent_check(&in->extents[cur], block, sb))) { 2241da177e4SLinus Torvalds in->lastextent = cur; 2251da177e4SLinus Torvalds return result; 2261da177e4SLinus Torvalds } 2271da177e4SLinus Torvalds } 2281da177e4SLinus Torvalds 2291da177e4SLinus Torvalds printk(KERN_ERR "EFS: map_block() failed to map block %u (dir)\n", block); 2301da177e4SLinus Torvalds return 0; 2311da177e4SLinus Torvalds } 2321da177e4SLinus Torvalds 2331da177e4SLinus Torvalds #ifdef DEBUG 2341da177e4SLinus Torvalds printk(KERN_DEBUG "EFS: map_block(): indirect search for logical block %u\n", block); 2351da177e4SLinus Torvalds #endif 2361da177e4SLinus Torvalds direxts = in->extents[0].cooked.ex_offset; 2371da177e4SLinus Torvalds indexts = in->numextents; 2381da177e4SLinus Torvalds 2391da177e4SLinus Torvalds for(indext = 0; indext < indexts; indext++) { 2401da177e4SLinus Torvalds cur = (last + indext) % indexts; 2411da177e4SLinus Torvalds 2421da177e4SLinus Torvalds /* 2431da177e4SLinus Torvalds * work out which direct extent contains `cur'. 2441da177e4SLinus Torvalds * 2451da177e4SLinus Torvalds * also compute ibase: i.e. the number of the first 2461da177e4SLinus Torvalds * indirect extent contained within direct extent `cur'. 2471da177e4SLinus Torvalds * 2481da177e4SLinus Torvalds */ 2491da177e4SLinus Torvalds ibase = 0; 2501da177e4SLinus Torvalds for(dirext = 0; cur < ibase && dirext < direxts; dirext++) { 2511da177e4SLinus Torvalds ibase += in->extents[dirext].cooked.ex_length * 2521da177e4SLinus Torvalds (EFS_BLOCKSIZE / sizeof(efs_extent)); 2531da177e4SLinus Torvalds } 2541da177e4SLinus Torvalds 2551da177e4SLinus Torvalds if (dirext == direxts) { 2561da177e4SLinus Torvalds /* should never happen */ 2571da177e4SLinus Torvalds printk(KERN_ERR "EFS: couldn't find direct extent for indirect extent %d (block %u)\n", cur, block); 2581da177e4SLinus Torvalds if (bh) brelse(bh); 2591da177e4SLinus Torvalds return 0; 2601da177e4SLinus Torvalds } 2611da177e4SLinus Torvalds 2621da177e4SLinus Torvalds /* work out block number and offset of this indirect extent */ 2631da177e4SLinus Torvalds iblock = sb->fs_start + in->extents[dirext].cooked.ex_bn + 2641da177e4SLinus Torvalds (cur - ibase) / 2651da177e4SLinus Torvalds (EFS_BLOCKSIZE / sizeof(efs_extent)); 2661da177e4SLinus Torvalds ioffset = (cur - ibase) % 2671da177e4SLinus Torvalds (EFS_BLOCKSIZE / sizeof(efs_extent)); 2681da177e4SLinus Torvalds 2691da177e4SLinus Torvalds if (first || lastblock != iblock) { 2701da177e4SLinus Torvalds if (bh) brelse(bh); 2711da177e4SLinus Torvalds 2721da177e4SLinus Torvalds bh = sb_bread(inode->i_sb, iblock); 2731da177e4SLinus Torvalds if (!bh) { 2741da177e4SLinus Torvalds printk(KERN_ERR "EFS: bread() failed at block %d\n", iblock); 2751da177e4SLinus Torvalds return 0; 2761da177e4SLinus Torvalds } 2771da177e4SLinus Torvalds #ifdef DEBUG 2781da177e4SLinus Torvalds printk(KERN_DEBUG "EFS: map_block(): read indirect extent block %d\n", iblock); 2791da177e4SLinus Torvalds #endif 2801da177e4SLinus Torvalds first = 0; 2811da177e4SLinus Torvalds lastblock = iblock; 2821da177e4SLinus Torvalds } 2831da177e4SLinus Torvalds 2841da177e4SLinus Torvalds exts = (efs_extent *) bh->b_data; 2851da177e4SLinus Torvalds 2861da177e4SLinus Torvalds extent_copy(&(exts[ioffset]), &ext); 2871da177e4SLinus Torvalds 2881da177e4SLinus Torvalds if (ext.cooked.ex_magic != 0) { 2891da177e4SLinus Torvalds printk(KERN_ERR "EFS: extent %d has bad magic number in block %d\n", cur, iblock); 2901da177e4SLinus Torvalds if (bh) brelse(bh); 2911da177e4SLinus Torvalds return 0; 2921da177e4SLinus Torvalds } 2931da177e4SLinus Torvalds 2941da177e4SLinus Torvalds if ((result = efs_extent_check(&ext, block, sb))) { 2951da177e4SLinus Torvalds if (bh) brelse(bh); 2961da177e4SLinus Torvalds in->lastextent = cur; 2971da177e4SLinus Torvalds return result; 2981da177e4SLinus Torvalds } 2991da177e4SLinus Torvalds } 3001da177e4SLinus Torvalds if (bh) brelse(bh); 3011da177e4SLinus Torvalds printk(KERN_ERR "EFS: map_block() failed to map block %u (indir)\n", block); 3021da177e4SLinus Torvalds return 0; 3031da177e4SLinus Torvalds } 3041da177e4SLinus Torvalds 3051da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 306