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	.llseek		= generic_file_llseek,
23	.readdir	= affs_readdir,
24	.fsync		= affs_file_fsync,
25};
26
27/*
28 * directories can handle most operations...
29 */
30const 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
42static int
43affs_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;
123inside:
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	}
144readdir_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
150readdir_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