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 56 pr_debug("AFFS: readdir(ino=%lu,f_pos=%lx)\n",inode->i_ino,(unsigned long)ctx->pos); 57 58 if (ctx->pos < 2) { 59 file->private_data = (void *)0; 60 if (!dir_emit_dots(file, ctx)) 61 return 0; 62 } 63 64 affs_lock_dir(inode); 65 chain_pos = (ctx->pos - 2) & 0xffff; 66 hash_pos = (ctx->pos - 2) >> 16; 67 if (chain_pos == 0xffff) { 68 affs_warning(sb, "readdir", "More than 65535 entries in chain"); 69 chain_pos = 0; 70 hash_pos++; 71 ctx->pos = ((hash_pos << 16) | chain_pos) + 2; 72 } 73 dir_bh = affs_bread(sb, inode->i_ino); 74 if (!dir_bh) 75 goto readdir_out; 76 77 /* If the directory hasn't changed since the last call to readdir(), 78 * we can jump directly to where we left off. 79 */ 80 ino = (u32)(long)file->private_data; 81 if (ino && file->f_version == inode->i_version) { 82 pr_debug("AFFS: readdir() left off=%d\n", ino); 83 goto inside; 84 } 85 86 ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]); 87 for (i = 0; ino && i < chain_pos; i++) { 88 fh_bh = affs_bread(sb, ino); 89 if (!fh_bh) { 90 affs_error(sb, "readdir","Cannot read block %d", i); 91 return -EIO; 92 } 93 ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain); 94 affs_brelse(fh_bh); 95 fh_bh = NULL; 96 } 97 if (ino) 98 goto inside; 99 hash_pos++; 100 101 for (; hash_pos < AFFS_SB(sb)->s_hashsize; hash_pos++) { 102 ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]); 103 if (!ino) 104 continue; 105 ctx->pos = (hash_pos << 16) + 2; 106 inside: 107 do { 108 fh_bh = affs_bread(sb, ino); 109 if (!fh_bh) { 110 affs_error(sb, "readdir","Cannot read block %d", ino); 111 break; 112 } 113 114 namelen = min(AFFS_TAIL(sb, fh_bh)->name[0], (u8)30); 115 name = AFFS_TAIL(sb, fh_bh)->name + 1; 116 pr_debug("AFFS: readdir(): filldir(\"%.*s\", ino=%u), hash=%d, f_pos=%x\n", 117 namelen, name, ino, hash_pos, (u32)ctx->pos); 118 if (!dir_emit(ctx, name, namelen, ino, DT_UNKNOWN)) 119 goto readdir_done; 120 ctx->pos++; 121 ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain); 122 affs_brelse(fh_bh); 123 fh_bh = NULL; 124 } while (ino); 125 } 126 readdir_done: 127 file->f_version = inode->i_version; 128 file->private_data = (void *)(long)ino; 129 130 readdir_out: 131 affs_brelse(dir_bh); 132 affs_brelse(fh_bh); 133 affs_unlock_dir(inode); 134 return 0; 135 } 136