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1// SPDX-License-Identifier: GPL-2.02/*3 * linux/fs/affs/dir.c4 *5 * (c) 1996 Hans-Joachim Widmaier - Rewritten6 *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 filesystem12 *13 * affs directory handling functions14 *15 */16 17#include <linux/iversion.h>18#include "affs.h"19 20struct affs_dir_data {21 unsigned long ino;22 u64 cookie;23};24 25static int affs_readdir(struct file *, struct dir_context *);26 27static loff_t affs_dir_llseek(struct file *file, loff_t offset, int whence)28{29 struct affs_dir_data *data = file->private_data;30 31 return generic_llseek_cookie(file, offset, whence, &data->cookie);32}33 34static int affs_dir_open(struct inode *inode, struct file *file)35{36 struct affs_dir_data *data;37 38 data = kzalloc(sizeof(struct affs_dir_data), GFP_KERNEL);39 if (!data)40 return -ENOMEM;41 file->private_data = data;42 return 0;43}44 45static int affs_dir_release(struct inode *inode, struct file *file)46{47 kfree(file->private_data);48 return 0;49}50 51const struct file_operations affs_dir_operations = {52 .open = affs_dir_open,53 .read = generic_read_dir,54 .llseek = affs_dir_llseek,55 .iterate_shared = affs_readdir,56 .fsync = affs_file_fsync,57 .release = affs_dir_release,58};59 60/*61 * directories can handle most operations...62 */63const struct inode_operations affs_dir_inode_operations = {64 .create = affs_create,65 .lookup = affs_lookup,66 .link = affs_link,67 .unlink = affs_unlink,68 .symlink = affs_symlink,69 .mkdir = affs_mkdir,70 .rmdir = affs_rmdir,71 .rename = affs_rename2,72 .setattr = affs_notify_change,73};74 75static int76affs_readdir(struct file *file, struct dir_context *ctx)77{78 struct inode *inode = file_inode(file);79 struct affs_dir_data *data = file->private_data;80 struct super_block *sb = inode->i_sb;81 struct buffer_head *dir_bh = NULL;82 struct buffer_head *fh_bh = NULL;83 unsigned char *name;84 int namelen;85 u32 i;86 int hash_pos;87 int chain_pos;88 u32 ino;89 int error = 0;90 91 pr_debug("%s(ino=%lu,f_pos=%llx)\n", __func__, inode->i_ino, ctx->pos);92 93 if (ctx->pos < 2) {94 data->ino = 0;95 if (!dir_emit_dots(file, ctx))96 return 0;97 }98 99 affs_lock_dir(inode);100 chain_pos = (ctx->pos - 2) & 0xffff;101 hash_pos = (ctx->pos - 2) >> 16;102 if (chain_pos == 0xffff) {103 affs_warning(sb, "readdir", "More than 65535 entries in chain");104 chain_pos = 0;105 hash_pos++;106 ctx->pos = ((hash_pos << 16) | chain_pos) + 2;107 }108 dir_bh = affs_bread(sb, inode->i_ino);109 if (!dir_bh)110 goto out_unlock_dir;111 112 /* If the directory hasn't changed since the last call to readdir(),113 * we can jump directly to where we left off.114 */115 ino = data->ino;116 if (ino && inode_eq_iversion(inode, data->cookie)) {117 pr_debug("readdir() left off=%d\n", ino);118 goto inside;119 }120 121 ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);122 for (i = 0; ino && i < chain_pos; i++) {123 fh_bh = affs_bread(sb, ino);124 if (!fh_bh) {125 affs_error(sb, "readdir","Cannot read block %d", i);126 error = -EIO;127 goto out_brelse_dir;128 }129 ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);130 affs_brelse(fh_bh);131 fh_bh = NULL;132 }133 if (ino)134 goto inside;135 hash_pos++;136 137 for (; hash_pos < AFFS_SB(sb)->s_hashsize; hash_pos++) {138 ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);139 if (!ino)140 continue;141 ctx->pos = (hash_pos << 16) + 2;142inside:143 do {144 fh_bh = affs_bread(sb, ino);145 if (!fh_bh) {146 affs_error(sb, "readdir",147 "Cannot read block %d", ino);148 break;149 }150 151 namelen = min(AFFS_TAIL(sb, fh_bh)->name[0],152 (u8)AFFSNAMEMAX);153 name = AFFS_TAIL(sb, fh_bh)->name + 1;154 pr_debug("readdir(): dir_emit(\"%.*s\", ino=%u), hash=%d, f_pos=%llx\n",155 namelen, name, ino, hash_pos, ctx->pos);156 157 if (!dir_emit(ctx, name, namelen, ino, DT_UNKNOWN))158 goto done;159 ctx->pos++;160 ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);161 affs_brelse(fh_bh);162 fh_bh = NULL;163 } while (ino);164 }165done:166 data->cookie = inode_query_iversion(inode);167 data->ino = ino;168 affs_brelse(fh_bh);169 170out_brelse_dir:171 affs_brelse(dir_bh);172 173out_unlock_dir:174 affs_unlock_dir(inode);175 return error;176}177