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 *, struct dir_context *); 19 20 const struct file_operations affs_dir_operations = { 21 .read = generic_read_dir, 22 .llseek = generic_file_llseek, 23 .iterate = affs_readdir, 24 .fsync = affs_file_fsync, 25 }; 26 27 /* 28 * directories can handle most operations... 29 */ 30 const struct inode_operations affs_dir_inode_operations = { 31 .create = affs_create, 32 .lookup = affs_lookup, 33 .link = affs_link, 34 .unlink = affs_unlink, 35 .symlink = affs_symlink, 36 .mkdir = affs_mkdir, 37 .rmdir = affs_rmdir, 38 .rename = affs_rename, 39 .setattr = affs_notify_change, 40 }; 41 42 static int 43 affs_readdir(struct file *file, struct dir_context *ctx) 44 { 45 struct inode *inode = file_inode(file); 46 struct super_block *sb = inode->i_sb; 47 struct buffer_head *dir_bh = NULL; 48 struct buffer_head *fh_bh = NULL; 49 unsigned char *name; 50 int namelen; 51 u32 i; 52 int hash_pos; 53 int chain_pos; 54 u32 ino; 55 int error = 0; 56 57 pr_debug("%s(ino=%lu,f_pos=%llx)\n", __func__, inode->i_ino, ctx->pos); 58 59 if (ctx->pos < 2) { 60 file->private_data = (void *)0; 61 if (!dir_emit_dots(file, ctx)) 62 return 0; 63 } 64 65 affs_lock_dir(inode); 66 chain_pos = (ctx->pos - 2) & 0xffff; 67 hash_pos = (ctx->pos - 2) >> 16; 68 if (chain_pos == 0xffff) { 69 affs_warning(sb, "readdir", "More than 65535 entries in chain"); 70 chain_pos = 0; 71 hash_pos++; 72 ctx->pos = ((hash_pos << 16) | chain_pos) + 2; 73 } 74 dir_bh = affs_bread(sb, inode->i_ino); 75 if (!dir_bh) 76 goto out_unlock_dir; 77 78 /* If the directory hasn't changed since the last call to readdir(), 79 * we can jump directly to where we left off. 80 */ 81 ino = (u32)(long)file->private_data; 82 if (ino && file->f_version == inode->i_version) { 83 pr_debug("readdir() left off=%d\n", ino); 84 goto inside; 85 } 86 87 ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]); 88 for (i = 0; ino && i < chain_pos; i++) { 89 fh_bh = affs_bread(sb, ino); 90 if (!fh_bh) { 91 affs_error(sb, "readdir","Cannot read block %d", i); 92 error = -EIO; 93 goto out_brelse_dir; 94 } 95 ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain); 96 affs_brelse(fh_bh); 97 fh_bh = NULL; 98 } 99 if (ino) 100 goto inside; 101 hash_pos++; 102 103 for (; hash_pos < AFFS_SB(sb)->s_hashsize; hash_pos++) { 104 ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]); 105 if (!ino) 106 continue; 107 ctx->pos = (hash_pos << 16) + 2; 108 inside: 109 do { 110 fh_bh = affs_bread(sb, ino); 111 if (!fh_bh) { 112 affs_error(sb, "readdir", 113 "Cannot read block %d", ino); 114 break; 115 } 116 117 namelen = min(AFFS_TAIL(sb, fh_bh)->name[0], 118 (u8)AFFSNAMEMAX); 119 name = AFFS_TAIL(sb, fh_bh)->name + 1; 120 pr_debug("readdir(): dir_emit(\"%.*s\", ino=%u), hash=%d, f_pos=%llx\n", 121 namelen, name, ino, hash_pos, ctx->pos); 122 123 if (!dir_emit(ctx, name, namelen, ino, DT_UNKNOWN)) 124 goto done; 125 ctx->pos++; 126 ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain); 127 affs_brelse(fh_bh); 128 fh_bh = NULL; 129 } while (ino); 130 } 131 done: 132 file->f_version = inode->i_version; 133 file->private_data = (void *)(long)ino; 134 affs_brelse(fh_bh); 135 136 out_brelse_dir: 137 affs_brelse(dir_bh); 138 139 out_unlock_dir: 140 affs_unlock_dir(inode); 141 return error; 142 } 143