| Kyle Swenson | 8d8f654 | 2021-03-15 11:02:55 -0600 | [diff] [blame] | 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 | } |