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*/
1 /*
2 * linux/fs/ufs/ufs_dir.c
3 *
4 * Copyright (C) 1996
5 * Adrian Rodriguez (adrian@franklins-tower.rutgers.edu)
6 * Laboratory for Computer Science Research Computing Facility
7 * Rutgers, The State University of New Jersey
8 *
9 * $Id: ufs_dir.c,v 1.1 1996/04/21 14:41:04 davem Exp $
10 *
11 */
12
13 #include <linux/fs.h>
14
15 /* XXX */
16 extern int ufs_lookup();
17 extern int ufs_bmap();
18
19 static int ufs_dir_read (struct inode * inode, struct file * filp,
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20 char * buf, int count)
21 {
22 /* XXX - probably allow this for root, EISDIR for normal users */
23 return -EISDIR;
24 }
25
26 /*
27 * This is blatantly stolen from ext2fs
28 */
29 static int
30 ufs_readdir (struct inode * inode, struct file * filp, void * dirent,
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31 filldir_t filldir)
32 {
33 int error = 0;
34 unsigned long offset, lblk, blk;
35 int i, stored;
36 struct buffer_head * bh;
37 struct direct * de;
38 struct super_block * sb;
39
40 if (!inode || !S_ISDIR(inode->i_mode))
41 return -EBADF;
42 sb = inode->i_sb;
43
44 if (inode->i_sb->u.ufs_sb.s_flags & UFS_DEBUG) {
45 printk("ufs_readdir: ino %lu f_pos %lu\n",
46 inode->i_ino, filp->f_pos);
47 ufs_print_inode(inode);
48 }
49
50 stored = 0;
51 bh = NULL;
52 offset = filp->f_pos & (sb->s_blocksize - 1);
53
54 while (!error && !stored && filp->f_pos < inode->i_size) {
55 lblk = (filp->f_pos) >> sb->s_blocksize_bits;
56 blk = ufs_bmap(inode, lblk);
57 /* XXX - ufs_bmap() call needs error checking */
58 blk = ufs_bmap(inode, lblk);
59 bh = bread (sb->s_dev, blk, sb->s_blocksize);
60 if (!bh) {
61 /* XXX - error - skip to the next block */
62 printk("ufs_readdir: dir inode %lu has a hole at offset %lu\n",
63 inode->i_ino, (unsigned long int)filp->f_pos);
64 filp->f_pos += sb->s_blocksize - offset;
65 continue;
66 }
67
68 revalidate:
69 /* If the dir block has changed since the last call to
70 * readdir(2), then we might be pointing to an invalid
71 * dirent right now. Scan from the start of the block
72 * to make sure. */
73 if (filp->f_version != inode->i_version) {
74 for (i = 0; i < sb->s_blocksize && i < offset; ) {
75 de = (struct direct *)
76 (bh->b_data + i);
77 /* It's too expensive to do a full
78 * dirent test each time round this
79 * loop, but we do have to test at
80 * least that it is non-zero. A
81 * failure will be detected in the
82 * dirent test below. */
83 if (de->d_reclen < 1)
84 break;
85 i += de->d_reclen;
86 }
87 offset = i;
88 filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
89 | offset;
90 filp->f_version = inode->i_version;
91 }
92
93 while (!error && filp->f_pos < inode->i_size
94 && offset < sb->s_blocksize) {
95 de = (struct direct *) (bh->b_data + offset);
96 /* XXX - put in a real ufs_check_dir_entry() */
97 if ((de->d_reclen == 0) || (de->d_namlen == 0)) {
98 filp->f_pos = filp->f_pos & (sb->s_blocksize - 1) + sb->s_blocksize;
99 brelse(bh);
100 return stored;
101 }
102 #if 0
103 if (!ext2_check_dir_entry ("ext2_readdir", inode, de,
104 bh, offset)) {
105 /* On error, skip the f_pos to the
106 next block. */
107 filp->f_pos = (filp->f_pos & (sb->s_blocksize - 1))
108 + sb->s_blocksize;
109 brelse (bh);
110 return stored;
111 }
112 #endif /* XXX */
113 offset += de->d_reclen;
114 if (de->d_ino) {
115 /* We might block in the next section
116 * if the data destination is
117 * currently swapped out. So, use a
118 * version stamp to detect whether or
119 * not the directory has been modified
120 * during the copy operation. */
121 unsigned long version;
122 dcache_add(inode, de->d_name, de->d_namlen,
123 de->d_ino);
124 version = inode->i_version;
125 if (inode->i_sb->u.ufs_sb.s_flags & UFS_DEBUG) {
126 printk("ufs_readdir: filldir(%s,%lu)\n",
127 de->d_name, de->d_ino);
128 }
129 error = filldir(dirent, de->d_name, de->d_namlen, filp->f_pos, de->d_ino);
130 if (error)
131 break;
132 if (version != inode->i_version)
133 goto revalidate;
134 stored ++;
135 }
136 filp->f_pos += de->d_reclen;
137 }
138 offset = 0;
139 brelse (bh);
140 }
141 #if 0 /* XXX */
142 if (!IS_RDONLY(inode)) {
143 inode->i_atime = CURRENT_TIME;
144 inode->i_dirt = 1;
145 }
146 #endif /* XXX */
147 return 0;
148 }
149
150
151 static struct file_operations ufs_dir_operations = {
152 NULL, /* lseek */
153 &ufs_dir_read, /* read */
154 NULL, /* write */
155 &ufs_readdir, /* readdir */
156 NULL, /* select */
157 NULL, /* ioctl */
158 NULL, /* mmap */
159 NULL, /* open */
160 NULL, /* release */
161 &file_fsync, /* fsync */
162 NULL, /* fasync */
163 NULL, /* check_media_change */
164 NULL, /* revalidate */
165 };
166
167 struct inode_operations ufs_dir_inode_operations = {
168 &ufs_dir_operations, /* default directory file operations */
169 NULL, /* create */
170 &ufs_lookup, /* lookup */
171 NULL, /* link */
172 NULL, /* unlink */
173 NULL, /* symlink */
174 NULL, /* mkdir */
175 NULL, /* rmdir */
176 NULL, /* mknod */
177 NULL, /* rename */
178 NULL, /* readlink */
179 NULL, /* follow_link */
180 NULL, /* readpage */
181 NULL, /* writepage */
182 NULL, /* bmap */
183 NULL, /* truncate */
184 NULL, /* permission */
185 NULL, /* smap */
186 };
187
188 /*
189 * Local Variables: ***
190 * c-indent-level: 8 ***
191 * c-continued-statement-offset: 8 ***
192 * c-brace-offset: -8 ***
193 * c-argdecl-indent: 0 ***
194 * c-label-offset: -8 ***
195 * End: ***
196 */
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*/