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