1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * linux/fs/affs/dir.c
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * (c) 1996 Hans-Joachim Widmaier - Rewritten
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * (C) 1993 Ray Burr - Modified for Amiga FFS filesystem.
8*4882a593Smuzhiyun *
9*4882a593Smuzhiyun * (C) 1992 Eric Youngdale Modified for ISO 9660 filesystem.
10*4882a593Smuzhiyun *
11*4882a593Smuzhiyun * (C) 1991 Linus Torvalds - minix filesystem
12*4882a593Smuzhiyun *
13*4882a593Smuzhiyun * affs directory handling functions
14*4882a593Smuzhiyun *
15*4882a593Smuzhiyun */
16*4882a593Smuzhiyun
17*4882a593Smuzhiyun #include <linux/iversion.h>
18*4882a593Smuzhiyun #include "affs.h"
19*4882a593Smuzhiyun
20*4882a593Smuzhiyun static int affs_readdir(struct file *, struct dir_context *);
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun const struct file_operations affs_dir_operations = {
23*4882a593Smuzhiyun .read = generic_read_dir,
24*4882a593Smuzhiyun .llseek = generic_file_llseek,
25*4882a593Smuzhiyun .iterate_shared = affs_readdir,
26*4882a593Smuzhiyun .fsync = affs_file_fsync,
27*4882a593Smuzhiyun };
28*4882a593Smuzhiyun
29*4882a593Smuzhiyun /*
30*4882a593Smuzhiyun * directories can handle most operations...
31*4882a593Smuzhiyun */
32*4882a593Smuzhiyun const struct inode_operations affs_dir_inode_operations = {
33*4882a593Smuzhiyun .create = affs_create,
34*4882a593Smuzhiyun .lookup = affs_lookup,
35*4882a593Smuzhiyun .link = affs_link,
36*4882a593Smuzhiyun .unlink = affs_unlink,
37*4882a593Smuzhiyun .symlink = affs_symlink,
38*4882a593Smuzhiyun .mkdir = affs_mkdir,
39*4882a593Smuzhiyun .rmdir = affs_rmdir,
40*4882a593Smuzhiyun .rename = affs_rename2,
41*4882a593Smuzhiyun .setattr = affs_notify_change,
42*4882a593Smuzhiyun };
43*4882a593Smuzhiyun
44*4882a593Smuzhiyun static int
affs_readdir(struct file * file,struct dir_context * ctx)45*4882a593Smuzhiyun affs_readdir(struct file *file, struct dir_context *ctx)
46*4882a593Smuzhiyun {
47*4882a593Smuzhiyun struct inode *inode = file_inode(file);
48*4882a593Smuzhiyun struct super_block *sb = inode->i_sb;
49*4882a593Smuzhiyun struct buffer_head *dir_bh = NULL;
50*4882a593Smuzhiyun struct buffer_head *fh_bh = NULL;
51*4882a593Smuzhiyun unsigned char *name;
52*4882a593Smuzhiyun int namelen;
53*4882a593Smuzhiyun u32 i;
54*4882a593Smuzhiyun int hash_pos;
55*4882a593Smuzhiyun int chain_pos;
56*4882a593Smuzhiyun u32 ino;
57*4882a593Smuzhiyun int error = 0;
58*4882a593Smuzhiyun
59*4882a593Smuzhiyun pr_debug("%s(ino=%lu,f_pos=%llx)\n", __func__, inode->i_ino, ctx->pos);
60*4882a593Smuzhiyun
61*4882a593Smuzhiyun if (ctx->pos < 2) {
62*4882a593Smuzhiyun file->private_data = (void *)0;
63*4882a593Smuzhiyun if (!dir_emit_dots(file, ctx))
64*4882a593Smuzhiyun return 0;
65*4882a593Smuzhiyun }
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun affs_lock_dir(inode);
68*4882a593Smuzhiyun chain_pos = (ctx->pos - 2) & 0xffff;
69*4882a593Smuzhiyun hash_pos = (ctx->pos - 2) >> 16;
70*4882a593Smuzhiyun if (chain_pos == 0xffff) {
71*4882a593Smuzhiyun affs_warning(sb, "readdir", "More than 65535 entries in chain");
72*4882a593Smuzhiyun chain_pos = 0;
73*4882a593Smuzhiyun hash_pos++;
74*4882a593Smuzhiyun ctx->pos = ((hash_pos << 16) | chain_pos) + 2;
75*4882a593Smuzhiyun }
76*4882a593Smuzhiyun dir_bh = affs_bread(sb, inode->i_ino);
77*4882a593Smuzhiyun if (!dir_bh)
78*4882a593Smuzhiyun goto out_unlock_dir;
79*4882a593Smuzhiyun
80*4882a593Smuzhiyun /* If the directory hasn't changed since the last call to readdir(),
81*4882a593Smuzhiyun * we can jump directly to where we left off.
82*4882a593Smuzhiyun */
83*4882a593Smuzhiyun ino = (u32)(long)file->private_data;
84*4882a593Smuzhiyun if (ino && inode_eq_iversion(inode, file->f_version)) {
85*4882a593Smuzhiyun pr_debug("readdir() left off=%d\n", ino);
86*4882a593Smuzhiyun goto inside;
87*4882a593Smuzhiyun }
88*4882a593Smuzhiyun
89*4882a593Smuzhiyun ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);
90*4882a593Smuzhiyun for (i = 0; ino && i < chain_pos; i++) {
91*4882a593Smuzhiyun fh_bh = affs_bread(sb, ino);
92*4882a593Smuzhiyun if (!fh_bh) {
93*4882a593Smuzhiyun affs_error(sb, "readdir","Cannot read block %d", i);
94*4882a593Smuzhiyun error = -EIO;
95*4882a593Smuzhiyun goto out_brelse_dir;
96*4882a593Smuzhiyun }
97*4882a593Smuzhiyun ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);
98*4882a593Smuzhiyun affs_brelse(fh_bh);
99*4882a593Smuzhiyun fh_bh = NULL;
100*4882a593Smuzhiyun }
101*4882a593Smuzhiyun if (ino)
102*4882a593Smuzhiyun goto inside;
103*4882a593Smuzhiyun hash_pos++;
104*4882a593Smuzhiyun
105*4882a593Smuzhiyun for (; hash_pos < AFFS_SB(sb)->s_hashsize; hash_pos++) {
106*4882a593Smuzhiyun ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);
107*4882a593Smuzhiyun if (!ino)
108*4882a593Smuzhiyun continue;
109*4882a593Smuzhiyun ctx->pos = (hash_pos << 16) + 2;
110*4882a593Smuzhiyun inside:
111*4882a593Smuzhiyun do {
112*4882a593Smuzhiyun fh_bh = affs_bread(sb, ino);
113*4882a593Smuzhiyun if (!fh_bh) {
114*4882a593Smuzhiyun affs_error(sb, "readdir",
115*4882a593Smuzhiyun "Cannot read block %d", ino);
116*4882a593Smuzhiyun break;
117*4882a593Smuzhiyun }
118*4882a593Smuzhiyun
119*4882a593Smuzhiyun namelen = min(AFFS_TAIL(sb, fh_bh)->name[0],
120*4882a593Smuzhiyun (u8)AFFSNAMEMAX);
121*4882a593Smuzhiyun name = AFFS_TAIL(sb, fh_bh)->name + 1;
122*4882a593Smuzhiyun pr_debug("readdir(): dir_emit(\"%.*s\", ino=%u), hash=%d, f_pos=%llx\n",
123*4882a593Smuzhiyun namelen, name, ino, hash_pos, ctx->pos);
124*4882a593Smuzhiyun
125*4882a593Smuzhiyun if (!dir_emit(ctx, name, namelen, ino, DT_UNKNOWN))
126*4882a593Smuzhiyun goto done;
127*4882a593Smuzhiyun ctx->pos++;
128*4882a593Smuzhiyun ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);
129*4882a593Smuzhiyun affs_brelse(fh_bh);
130*4882a593Smuzhiyun fh_bh = NULL;
131*4882a593Smuzhiyun } while (ino);
132*4882a593Smuzhiyun }
133*4882a593Smuzhiyun done:
134*4882a593Smuzhiyun file->f_version = inode_query_iversion(inode);
135*4882a593Smuzhiyun file->private_data = (void *)(long)ino;
136*4882a593Smuzhiyun affs_brelse(fh_bh);
137*4882a593Smuzhiyun
138*4882a593Smuzhiyun out_brelse_dir:
139*4882a593Smuzhiyun affs_brelse(dir_bh);
140*4882a593Smuzhiyun
141*4882a593Smuzhiyun out_unlock_dir:
142*4882a593Smuzhiyun affs_unlock_dir(inode);
143*4882a593Smuzhiyun return error;
144*4882a593Smuzhiyun }
145