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
18static int affs_readdir(struct file *, void *, filldir_t);
19
20const struct file_operations affs_dir_operations = {
21	.read		= generic_read_dir,
22	.readdir	= affs_readdir,
23	.fsync		= file_fsync,
24};
25
26/*
27 * directories can handle most operations...
28 */
29const struct inode_operations affs_dir_inode_operations = {
30	.create		= affs_create,
31	.lookup		= affs_lookup,
32	.link		= affs_link,
33	.unlink		= affs_unlink,
34	.symlink	= affs_symlink,
35	.mkdir		= affs_mkdir,
36	.rmdir		= affs_rmdir,
37	.rename		= affs_rename,
38	.setattr	= affs_notify_change,
39};
40
41static int
42affs_readdir(struct file *filp, void *dirent, filldir_t filldir)
43{
44	struct inode		*inode = filp->f_path.dentry->d_inode;
45	struct super_block	*sb = inode->i_sb;
46	struct buffer_head	*dir_bh;
47	struct buffer_head	*fh_bh;
48	unsigned char		*name;
49	int			 namelen;
50	u32			 i;
51	int			 hash_pos;
52	int			 chain_pos;
53	u32			 f_pos;
54	u32			 ino;
55	int			 stored;
56	int			 res;
57
58	pr_debug("AFFS: readdir(ino=%lu,f_pos=%lx)\n",inode->i_ino,(unsigned long)filp->f_pos);
59
60	stored = 0;
61	res    = -EIO;
62	dir_bh = NULL;
63	fh_bh  = NULL;
64	f_pos  = filp->f_pos;
65
66	if (f_pos == 0) {
67		filp->private_data = (void *)0;
68		if (filldir(dirent, ".", 1, f_pos, inode->i_ino, DT_DIR) < 0)
69			return 0;
70		filp->f_pos = f_pos = 1;
71		stored++;
72	}
73	if (f_pos == 1) {
74		if (filldir(dirent, "..", 2, f_pos, parent_ino(filp->f_path.dentry), DT_DIR) < 0)
75			return stored;
76		filp->f_pos = f_pos = 2;
77		stored++;
78	}
79
80	affs_lock_dir(inode);
81	chain_pos = (f_pos - 2) & 0xffff;
82	hash_pos  = (f_pos - 2) >> 16;
83	if (chain_pos == 0xffff) {
84		affs_warning(sb, "readdir", "More than 65535 entries in chain");
85		chain_pos = 0;
86		hash_pos++;
87		filp->f_pos = ((hash_pos << 16) | chain_pos) + 2;
88	}
89	dir_bh = affs_bread(sb, inode->i_ino);
90	if (!dir_bh)
91		goto readdir_out;
92
93	/* If the directory hasn't changed since the last call to readdir(),
94	 * we can jump directly to where we left off.
95	 */
96	ino = (u32)(long)filp->private_data;
97	if (ino && filp->f_version == inode->i_version) {
98		pr_debug("AFFS: readdir() left off=%d\n", ino);
99		goto inside;
100	}
101
102	ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);
103	for (i = 0; ino && i < chain_pos; i++) {
104		fh_bh = affs_bread(sb, ino);
105		if (!fh_bh) {
106			affs_error(sb, "readdir","Cannot read block %d", i);
107			goto readdir_out;
108		}
109		ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);
110		affs_brelse(fh_bh);
111		fh_bh = NULL;
112	}
113	if (ino)
114		goto inside;
115	hash_pos++;
116
117	for (; hash_pos < AFFS_SB(sb)->s_hashsize; hash_pos++) {
118		ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);
119		if (!ino)
120			continue;
121		f_pos = (hash_pos << 16) + 2;
122inside:
123		do {
124			fh_bh = affs_bread(sb, ino);
125			if (!fh_bh) {
126				affs_error(sb, "readdir","Cannot read block %d", ino);
127				goto readdir_done;
128			}
129
130			namelen = min(AFFS_TAIL(sb, fh_bh)->name[0], (u8)30);
131			name = AFFS_TAIL(sb, fh_bh)->name + 1;
132			pr_debug("AFFS: readdir(): filldir(\"%.*s\", ino=%u), hash=%d, f_pos=%x\n",
133				 namelen, name, ino, hash_pos, f_pos);
134			if (filldir(dirent, name, namelen, f_pos, ino, DT_UNKNOWN) < 0)
135				goto readdir_done;
136			stored++;
137			f_pos++;
138			ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);
139			affs_brelse(fh_bh);
140			fh_bh = NULL;
141		} while (ino);
142	}
143readdir_done:
144	filp->f_pos = f_pos;
145	filp->f_version = inode->i_version;
146	filp->private_data = (void *)(long)ino;
147	res = stored;
148
149readdir_out:
150	affs_brelse(dir_bh);
151	affs_brelse(fh_bh);
152	affs_unlock_dir(inode);
153	pr_debug("AFFS: readdir()=%d\n", stored);
154	return res;
155}
156