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 *, void *, filldir_t);
19
20 const struct file_operations affs_dir_operations = {
21 .read = generic_read_dir,
22 .llseek = generic_file_llseek,
23 .readdir = 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
affs_readdir(struct file * filp,void * dirent,filldir_t filldir)43 affs_readdir(struct file *filp, void *dirent, filldir_t filldir)
44 {
45 struct inode *inode = filp->f_path.dentry->d_inode;
46 struct super_block *sb = inode->i_sb;
47 struct buffer_head *dir_bh;
48 struct buffer_head *fh_bh;
49 unsigned char *name;
50 int namelen;
51 u32 i;
52 int hash_pos;
53 int chain_pos;
54 u32 f_pos;
55 u32 ino;
56 int stored;
57 int res;
58
59 pr_debug("AFFS: readdir(ino=%lu,f_pos=%lx)\n",inode->i_ino,(unsigned long)filp->f_pos);
60
61 stored = 0;
62 res = -EIO;
63 dir_bh = NULL;
64 fh_bh = NULL;
65 f_pos = filp->f_pos;
66
67 if (f_pos == 0) {
68 filp->private_data = (void *)0;
69 if (filldir(dirent, ".", 1, f_pos, inode->i_ino, DT_DIR) < 0)
70 return 0;
71 filp->f_pos = f_pos = 1;
72 stored++;
73 }
74 if (f_pos == 1) {
75 if (filldir(dirent, "..", 2, f_pos, parent_ino(filp->f_path.dentry), DT_DIR) < 0)
76 return stored;
77 filp->f_pos = f_pos = 2;
78 stored++;
79 }
80
81 affs_lock_dir(inode);
82 chain_pos = (f_pos - 2) & 0xffff;
83 hash_pos = (f_pos - 2) >> 16;
84 if (chain_pos == 0xffff) {
85 affs_warning(sb, "readdir", "More than 65535 entries in chain");
86 chain_pos = 0;
87 hash_pos++;
88 filp->f_pos = ((hash_pos << 16) | chain_pos) + 2;
89 }
90 dir_bh = affs_bread(sb, inode->i_ino);
91 if (!dir_bh)
92 goto readdir_out;
93
94 /* If the directory hasn't changed since the last call to readdir(),
95 * we can jump directly to where we left off.
96 */
97 ino = (u32)(long)filp->private_data;
98 if (ino && filp->f_version == inode->i_version) {
99 pr_debug("AFFS: readdir() left off=%d\n", ino);
100 goto inside;
101 }
102
103 ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);
104 for (i = 0; ino && i < chain_pos; i++) {
105 fh_bh = affs_bread(sb, ino);
106 if (!fh_bh) {
107 affs_error(sb, "readdir","Cannot read block %d", i);
108 goto readdir_out;
109 }
110 ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);
111 affs_brelse(fh_bh);
112 fh_bh = NULL;
113 }
114 if (ino)
115 goto inside;
116 hash_pos++;
117
118 for (; hash_pos < AFFS_SB(sb)->s_hashsize; hash_pos++) {
119 ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);
120 if (!ino)
121 continue;
122 f_pos = (hash_pos << 16) + 2;
123 inside:
124 do {
125 fh_bh = affs_bread(sb, ino);
126 if (!fh_bh) {
127 affs_error(sb, "readdir","Cannot read block %d", ino);
128 goto readdir_done;
129 }
130
131 namelen = min(AFFS_TAIL(sb, fh_bh)->name[0], (u8)30);
132 name = AFFS_TAIL(sb, fh_bh)->name + 1;
133 pr_debug("AFFS: readdir(): filldir(\"%.*s\", ino=%u), hash=%d, f_pos=%x\n",
134 namelen, name, ino, hash_pos, f_pos);
135 if (filldir(dirent, name, namelen, f_pos, ino, DT_UNKNOWN) < 0)
136 goto readdir_done;
137 stored++;
138 f_pos++;
139 ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);
140 affs_brelse(fh_bh);
141 fh_bh = NULL;
142 } while (ino);
143 }
144 readdir_done:
145 filp->f_pos = f_pos;
146 filp->f_version = inode->i_version;
147 filp->private_data = (void *)(long)ino;
148 res = stored;
149
150 readdir_out:
151 affs_brelse(dir_bh);
152 affs_brelse(fh_bh);
153 affs_unlock_dir(inode);
154 pr_debug("AFFS: readdir()=%d\n", stored);
155 return res;
156 }
157