1 /* 2 * linux/fs/affs/dir.c 3 * 4 * (c) 1996 Hans-Joachim Widmaier - Rewritten 5 * 6 * (C) 1993 Ray Burr - Modified for Amiga FFS filesystem. 7 * 8 * (C) 1992 Eric Youngdale Modified for ISO 9660 filesystem. 9 * 10 * (C) 1991 Linus Torvalds - minix filesystem 11 * 12 * affs directory handling functions 13 * 14 */ 15 16 #include "affs.h" 17 18 static int affs_readdir(struct file *, void *, filldir_t); 19 20 const struct file_operations affs_dir_operations = { 21 .read = generic_read_dir, 22 .readdir = affs_readdir, 23 .fsync = file_fsync, 24 }; 25 26 /* 27 * directories can handle most operations... 28 */ 29 const struct inode_operations affs_dir_inode_operations = { 30 .create = affs_create, 31 .lookup = affs_lookup, 32 .link = affs_link, 33 .unlink = affs_unlink, 34 .symlink = affs_symlink, 35 .mkdir = affs_mkdir, 36 .rmdir = affs_rmdir, 37 .rename = affs_rename, 38 .setattr = affs_notify_change, 39 }; 40 41 static int 42 affs_readdir(struct file *filp, void *dirent, filldir_t filldir) 43 { 44 struct inode *inode = filp->f_path.dentry->d_inode; 45 struct super_block *sb = inode->i_sb; 46 struct buffer_head *dir_bh; 47 struct buffer_head *fh_bh; 48 unsigned char *name; 49 int namelen; 50 u32 i; 51 int hash_pos; 52 int chain_pos; 53 u32 f_pos; 54 u32 ino; 55 int stored; 56 int res; 57 58 pr_debug("AFFS: readdir(ino=%lu,f_pos=%lx)\n",inode->i_ino,(unsigned long)filp->f_pos); 59 60 stored = 0; 61 res = -EIO; 62 dir_bh = NULL; 63 fh_bh = NULL; 64 f_pos = filp->f_pos; 65 66 if (f_pos == 0) { 67 filp->private_data = (void *)0; 68 if (filldir(dirent, ".", 1, f_pos, inode->i_ino, DT_DIR) < 0) 69 return 0; 70 filp->f_pos = f_pos = 1; 71 stored++; 72 } 73 if (f_pos == 1) { 74 if (filldir(dirent, "..", 2, f_pos, parent_ino(filp->f_path.dentry), DT_DIR) < 0) 75 return stored; 76 filp->f_pos = f_pos = 2; 77 stored++; 78 } 79 80 affs_lock_dir(inode); 81 chain_pos = (f_pos - 2) & 0xffff; 82 hash_pos = (f_pos - 2) >> 16; 83 if (chain_pos == 0xffff) { 84 affs_warning(sb, "readdir", "More than 65535 entries in chain"); 85 chain_pos = 0; 86 hash_pos++; 87 filp->f_pos = ((hash_pos << 16) | chain_pos) + 2; 88 } 89 dir_bh = affs_bread(sb, inode->i_ino); 90 if (!dir_bh) 91 goto readdir_out; 92 93 /* If the directory hasn't changed since the last call to readdir(), 94 * we can jump directly to where we left off. 95 */ 96 ino = (u32)(long)filp->private_data; 97 if (ino && filp->f_version == inode->i_version) { 98 pr_debug("AFFS: readdir() left off=%d\n", ino); 99 goto inside; 100 } 101 102 ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]); 103 for (i = 0; ino && i < chain_pos; i++) { 104 fh_bh = affs_bread(sb, ino); 105 if (!fh_bh) { 106 affs_error(sb, "readdir","Cannot read block %d", i); 107 goto readdir_out; 108 } 109 ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain); 110 affs_brelse(fh_bh); 111 fh_bh = NULL; 112 } 113 if (ino) 114 goto inside; 115 hash_pos++; 116 117 for (; hash_pos < AFFS_SB(sb)->s_hashsize; hash_pos++) { 118 ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]); 119 if (!ino) 120 continue; 121 f_pos = (hash_pos << 16) + 2; 122 inside: 123 do { 124 fh_bh = affs_bread(sb, ino); 125 if (!fh_bh) { 126 affs_error(sb, "readdir","Cannot read block %d", ino); 127 goto readdir_done; 128 } 129 130 namelen = min(AFFS_TAIL(sb, fh_bh)->name[0], (u8)30); 131 name = AFFS_TAIL(sb, fh_bh)->name + 1; 132 pr_debug("AFFS: readdir(): filldir(\"%.*s\", ino=%u), hash=%d, f_pos=%x\n", 133 namelen, name, ino, hash_pos, f_pos); 134 if (filldir(dirent, name, namelen, f_pos, ino, DT_UNKNOWN) < 0) 135 goto readdir_done; 136 stored++; 137 f_pos++; 138 ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain); 139 affs_brelse(fh_bh); 140 fh_bh = NULL; 141 } while (ino); 142 } 143 readdir_done: 144 filp->f_pos = f_pos; 145 filp->f_version = inode->i_version; 146 filp->private_data = (void *)(long)ino; 147 res = stored; 148 149 readdir_out: 150 affs_brelse(dir_bh); 151 affs_brelse(fh_bh); 152 affs_unlock_dir(inode); 153 pr_debug("AFFS: readdir()=%d\n", stored); 154 return res; 155 } 156