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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
21struct affs_dir_data {
22 unsigned long ino;
23 u64 cookie;
24};
25
26static int affs_readdir(struct file *, struct dir_context *);
27
28static 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
35static int affs_dir_open(struct inode *inode, struct file *file)
36{
37 struct affs_dir_data *data;
38
39 data = kzalloc_obj(struct affs_dir_data);
40 if (!data)
41 return -ENOMEM;
42 file->private_data = data;
43 return 0;
44}
45
46static int affs_dir_release(struct inode *inode, struct file *file)
47{
48 kfree(file->private_data);
49 return 0;
50}
51
52const 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 */
65const 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_setattr,
75};
76
77static int
78affs_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=%llu,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 if (hash_pos >= AFFS_SB(sb)->s_hashsize)
123 goto done;
124
125 ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);
126 for (i = 0; ino && i < chain_pos; i++) {
127 fh_bh = affs_bread(sb, ino);
128 if (!fh_bh) {
129 affs_error(sb, "readdir","Cannot read block %d", i);
130 error = -EIO;
131 goto out_brelse_dir;
132 }
133 ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);
134 affs_brelse(fh_bh);
135 fh_bh = NULL;
136 }
137 if (ino)
138 goto inside;
139 hash_pos++;
140
141 for (; hash_pos < AFFS_SB(sb)->s_hashsize; hash_pos++) {
142 ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);
143 if (!ino)
144 continue;
145 ctx->pos = (hash_pos << 16) + 2;
146inside:
147 do {
148 fh_bh = affs_bread(sb, ino);
149 if (!fh_bh) {
150 affs_error(sb, "readdir",
151 "Cannot read block %d", ino);
152 break;
153 }
154
155 namelen = min(AFFS_TAIL(sb, fh_bh)->name[0],
156 (u8)AFFSNAMEMAX);
157 name = AFFS_TAIL(sb, fh_bh)->name + 1;
158 pr_debug("readdir(): dir_emit(\"%.*s\", ino=%u), hash=%d, f_pos=%llx\n",
159 namelen, name, ino, hash_pos, ctx->pos);
160
161 if (!dir_emit(ctx, name, namelen, ino, DT_UNKNOWN))
162 goto done;
163 ctx->pos++;
164 ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);
165 affs_brelse(fh_bh);
166 fh_bh = NULL;
167 } while (ino);
168 }
169done:
170 data->cookie = inode_query_iversion(inode);
171 data->ino = ino;
172 affs_brelse(fh_bh);
173
174out_brelse_dir:
175 affs_brelse(dir_bh);
176
177out_unlock_dir:
178 affs_unlock_dir(inode);
179 return error;
180}