1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/affs/dir.c 4 * 5 * (c) 1996 Hans-Joachim Widmaier - Rewritten 6 * 7 * (C) 1993 Ray Burr - Modified for Amiga FFS filesystem. 8 * 9 * (C) 1992 Eric Youngdale Modified for ISO 9660 filesystem. 10 * 11 * (C) 1991 Linus Torvalds - minix filesystem 12 * 13 * affs directory handling functions 14 * 15 */ 16 17 #include <linux/iversion.h> 18 #include <linux/filelock.h> 19 #include "affs.h" 20 21 struct affs_dir_data { 22 unsigned long ino; 23 u64 cookie; 24 }; 25 26 static int affs_readdir(struct file *, struct dir_context *); 27 28 static loff_t affs_dir_llseek(struct file *file, loff_t offset, int whence) 29 { 30 struct affs_dir_data *data = file->private_data; 31 32 return generic_llseek_cookie(file, offset, whence, &data->cookie); 33 } 34 35 static int affs_dir_open(struct inode *inode, struct file *file) 36 { 37 struct affs_dir_data *data; 38 39 data = kzalloc(sizeof(struct affs_dir_data), GFP_KERNEL); 40 if (!data) 41 return -ENOMEM; 42 file->private_data = data; 43 return 0; 44 } 45 46 static int affs_dir_release(struct inode *inode, struct file *file) 47 { 48 kfree(file->private_data); 49 return 0; 50 } 51 52 const struct file_operations affs_dir_operations = { 53 .open = affs_dir_open, 54 .read = generic_read_dir, 55 .llseek = affs_dir_llseek, 56 .iterate_shared = affs_readdir, 57 .fsync = affs_file_fsync, 58 .release = affs_dir_release, 59 .setlease = generic_setlease, 60 }; 61 62 /* 63 * directories can handle most operations... 64 */ 65 const struct inode_operations affs_dir_inode_operations = { 66 .create = affs_create, 67 .lookup = affs_lookup, 68 .link = affs_link, 69 .unlink = affs_unlink, 70 .symlink = affs_symlink, 71 .mkdir = affs_mkdir, 72 .rmdir = affs_rmdir, 73 .rename = affs_rename2, 74 .setattr = affs_notify_change, 75 }; 76 77 static int 78 affs_readdir(struct file *file, struct dir_context *ctx) 79 { 80 struct inode *inode = file_inode(file); 81 struct affs_dir_data *data = file->private_data; 82 struct super_block *sb = inode->i_sb; 83 struct buffer_head *dir_bh = NULL; 84 struct buffer_head *fh_bh = NULL; 85 unsigned char *name; 86 int namelen; 87 u32 i; 88 int hash_pos; 89 int chain_pos; 90 u32 ino; 91 int error = 0; 92 93 pr_debug("%s(ino=%lu,f_pos=%llx)\n", __func__, inode->i_ino, ctx->pos); 94 95 if (ctx->pos < 2) { 96 data->ino = 0; 97 if (!dir_emit_dots(file, ctx)) 98 return 0; 99 } 100 101 affs_lock_dir(inode); 102 chain_pos = (ctx->pos - 2) & 0xffff; 103 hash_pos = (ctx->pos - 2) >> 16; 104 if (chain_pos == 0xffff) { 105 affs_warning(sb, "readdir", "More than 65535 entries in chain"); 106 chain_pos = 0; 107 hash_pos++; 108 ctx->pos = ((hash_pos << 16) | chain_pos) + 2; 109 } 110 dir_bh = affs_bread(sb, inode->i_ino); 111 if (!dir_bh) 112 goto out_unlock_dir; 113 114 /* If the directory hasn't changed since the last call to readdir(), 115 * we can jump directly to where we left off. 116 */ 117 ino = data->ino; 118 if (ino && inode_eq_iversion(inode, data->cookie)) { 119 pr_debug("readdir() left off=%d\n", ino); 120 goto inside; 121 } 122 123 ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]); 124 for (i = 0; ino && i < chain_pos; i++) { 125 fh_bh = affs_bread(sb, ino); 126 if (!fh_bh) { 127 affs_error(sb, "readdir","Cannot read block %d", i); 128 error = -EIO; 129 goto out_brelse_dir; 130 } 131 ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain); 132 affs_brelse(fh_bh); 133 fh_bh = NULL; 134 } 135 if (ino) 136 goto inside; 137 hash_pos++; 138 139 for (; hash_pos < AFFS_SB(sb)->s_hashsize; hash_pos++) { 140 ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]); 141 if (!ino) 142 continue; 143 ctx->pos = (hash_pos << 16) + 2; 144 inside: 145 do { 146 fh_bh = affs_bread(sb, ino); 147 if (!fh_bh) { 148 affs_error(sb, "readdir", 149 "Cannot read block %d", ino); 150 break; 151 } 152 153 namelen = min(AFFS_TAIL(sb, fh_bh)->name[0], 154 (u8)AFFSNAMEMAX); 155 name = AFFS_TAIL(sb, fh_bh)->name + 1; 156 pr_debug("readdir(): dir_emit(\"%.*s\", ino=%u), hash=%d, f_pos=%llx\n", 157 namelen, name, ino, hash_pos, ctx->pos); 158 159 if (!dir_emit(ctx, name, namelen, ino, DT_UNKNOWN)) 160 goto done; 161 ctx->pos++; 162 ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain); 163 affs_brelse(fh_bh); 164 fh_bh = NULL; 165 } while (ino); 166 } 167 done: 168 data->cookie = inode_query_iversion(inode); 169 data->ino = ino; 170 affs_brelse(fh_bh); 171 172 out_brelse_dir: 173 affs_brelse(dir_bh); 174 175 out_unlock_dir: 176 affs_unlock_dir(inode); 177 return error; 178 } 179