1 /*
2 * linux/fs/adfs/inode.c
3 *
4 * Copyright (C) 1997-1999 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10 #include <linux/version.h>
11 #include <linux/errno.h>
12 #include <linux/fs.h>
13 #include <linux/adfs_fs.h>
14 #include <linux/sched.h>
15 #include <linux/stat.h>
16 #include <linux/string.h>
17 #include <linux/locks.h>
18 #include <linux/mm.h>
19 #include <linux/smp_lock.h>
20
21 #include "adfs.h"
22
23 /*
24 * Lookup/Create a block at offset 'block' into 'inode'. We currently do
25 * not support creation of new blocks, so we return -EIO for this case.
26 */
27 int
28 adfs_get_block(struct inode *inode, long block, struct buffer_head *bh, int create)
29 {
30 if (block < 0)
31 goto abort_negative;
32
33 if (!create) {
34 if (block >= inode->i_blocks)
35 goto abort_toobig;
36
37 block = __adfs_block_map(inode->i_sb, inode->i_ino, block);
38 if (block) {
39 bh->b_dev = inode->i_dev;
40 bh->b_blocknr = block;
41 bh->b_state |= (1UL << BH_Mapped);
42 }
43 return 0;
44 }
45 /* don't support allocation of blocks yet */
46 return -EIO;
47
48 abort_negative:
49 adfs_error(inode->i_sb, "block %d < 0", block);
50 return -EIO;
51
52 abort_toobig:
53 return 0;
54 }
55
56 static int adfs_writepage(struct page *page)
57 {
58 return block_write_full_page(page, adfs_get_block);
59 }
60
61 static int adfs_readpage(struct file *file, struct page *page)
62 {
63 return block_read_full_page(page, adfs_get_block);
64 }
65
66 static int adfs_prepare_write(struct file *file, struct page *page, unsigned int from, unsigned int to)
67 {
68 return cont_prepare_write(page, from, to, adfs_get_block,
69 &page->mapping->host->u.adfs_i.mmu_private);
70 }
71
72 static int _adfs_bmap(struct address_space *mapping, long block)
73 {
74 return generic_block_bmap(mapping, block, adfs_get_block);
75 }
76
77 static struct address_space_operations adfs_aops = {
78 readpage: adfs_readpage,
79 writepage: adfs_writepage,
80 sync_page: block_sync_page,
81 prepare_write: adfs_prepare_write,
82 commit_write: generic_commit_write,
83 bmap: _adfs_bmap
84 };
85
86 static inline unsigned int
87 adfs_filetype(struct inode *inode)
88 {
89 unsigned int type;
90
91 if (inode->u.adfs_i.stamped)
92 type = (inode->u.adfs_i.loadaddr >> 8) & 0xfff;
93 else
94 type = (unsigned int) -1;
95
96 return type;
97 }
98
99 /*
100 * Convert ADFS attributes and filetype to Linux permission.
101 */
102 static umode_t
103 adfs_atts2mode(struct super_block *sb, struct inode *inode)
104 {
105 unsigned int filetype, attr = inode->u.adfs_i.attr;
106 umode_t mode, rmask;
107
108 if (attr & ADFS_NDA_DIRECTORY) {
109 mode = S_IRUGO & sb->u.adfs_sb.s_owner_mask;
110 return S_IFDIR | S_IXUGO | mode;
111 }
112
113 filetype = adfs_filetype(inode);
114
115 switch (filetype) {
116 case 0xfc0: /* LinkFS */
117 return S_IFLNK|S_IRWXUGO;
118
119 case 0xfe6: /* UnixExec */
120 rmask = S_IRUGO | S_IXUGO;
121 break;
122
123 default:
124 rmask = S_IRUGO;
125 }
126
127 mode = S_IFREG;
128
129 if (attr & ADFS_NDA_OWNER_READ)
130 mode |= rmask & sb->u.adfs_sb.s_owner_mask;
131
132 if (attr & ADFS_NDA_OWNER_WRITE)
133 mode |= S_IWUGO & sb->u.adfs_sb.s_owner_mask;
134
135 if (attr & ADFS_NDA_PUBLIC_READ)
136 mode |= rmask & sb->u.adfs_sb.s_other_mask;
137
138 if (attr & ADFS_NDA_PUBLIC_WRITE)
139 mode |= S_IWUGO & sb->u.adfs_sb.s_other_mask;
140 return mode;
141 }
142
143 /*
144 * Convert Linux permission to ADFS attribute. We try to do the reverse
145 * of atts2mode, but there is not a 1:1 translation.
146 */
147 static int
148 adfs_mode2atts(struct super_block *sb, struct inode *inode)
149 {
150 umode_t mode;
151 int attr;
152
153 /* FIXME: should we be able to alter a link? */
154 if (S_ISLNK(inode->i_mode))
155 return inode->u.adfs_i.attr;
156
157 if (S_ISDIR(inode->i_mode))
158 attr = ADFS_NDA_DIRECTORY;
159 else
160 attr = 0;
161
162 mode = inode->i_mode & sb->u.adfs_sb.s_owner_mask;
163 if (mode & S_IRUGO)
164 attr |= ADFS_NDA_OWNER_READ;
165 if (mode & S_IWUGO)
166 attr |= ADFS_NDA_OWNER_WRITE;
167
168 mode = inode->i_mode & sb->u.adfs_sb.s_other_mask;
169 mode &= ~sb->u.adfs_sb.s_owner_mask;
170 if (mode & S_IRUGO)
171 attr |= ADFS_NDA_PUBLIC_READ;
172 if (mode & S_IWUGO)
173 attr |= ADFS_NDA_PUBLIC_WRITE;
174
175 return attr;
176 }
177
178 /*
179 * Convert an ADFS time to Unix time. ADFS has a 40-bit centi-second time
180 * referenced to 1 Jan 1900 (til 2248)
181 */
182 static unsigned int
183 adfs_adfs2unix_time(struct inode *inode)
184 {
185 unsigned int high, low;
186
187 if (inode->u.adfs_i.stamped == 0)
188 return CURRENT_TIME;
189
190 high = inode->u.adfs_i.loadaddr << 24;
191 low = inode->u.adfs_i.execaddr;
192
193 high |= low >> 8;
194 low &= 255;
195
196 /* Files dated pre 01 Jan 1970 00:00:00. */
197 if (high < 0x336e996a)
198 return 0;
199
200 /* Files dated post 18 Jan 2038 03:14:05. */
201 if (high >= 0x656e9969)
202 return 0x7ffffffd;
203
204 /* discard 2208988800 (0x336e996a00) seconds of time */
205 high -= 0x336e996a;
206
207 /* convert 40-bit centi-seconds to 32-bit seconds */
208 return (((high % 100) << 8) + low) / 100 + (high / 100 << 8);
209 }
210
211 /*
212 * Convert an Unix time to ADFS time. We only do this if the entry has a
213 * time/date stamp already.
214 */
215 static void
216 adfs_unix2adfs_time(struct inode *inode, unsigned int secs)
217 {
218 unsigned int high, low;
219
220 if (inode->u.adfs_i.stamped) {
221 /* convert 32-bit seconds to 40-bit centi-seconds */
222 low = (secs & 255) * 100;
223 high = (secs / 256) * 100 + (low << 8) + 0x336e996a;
224
225 inode->u.adfs_i.loadaddr = (high >> 24) |
226 (inode->u.adfs_i.loadaddr & ~0xff);
227 inode->u.adfs_i.execaddr = (low & 255) | (high << 8);
228 }
229 }
230
231 /*
232 * Fill in the inode information from the object information.
233 *
234 * Note that this is an inode-less filesystem, so we can't use the inode
235 * number to reference the metadata on the media. Instead, we use the
236 * inode number to hold the object ID, which in turn will tell us where
237 * the data is held. We also save the parent object ID, and with these
238 * two, we can locate the metadata.
239 *
240 * This does mean that we rely on an objects parent remaining the same at
241 * all times - we cannot cope with a cross-directory rename (yet).
242 */
243 struct inode *
244 adfs_iget(struct super_block *sb, struct object_info *obj)
245 {
246 struct inode *inode;
247
248 inode = new_inode(sb);
249 if (!inode)
250 goto out;
251
252 inode->i_version = ++event;
253 inode->i_uid = sb->u.adfs_sb.s_uid;
254 inode->i_gid = sb->u.adfs_sb.s_gid;
255 inode->i_ino = obj->file_id;
256 inode->i_size = obj->size;
257 inode->i_nlink = 2;
258 inode->i_blksize = PAGE_SIZE;
259 inode->i_blocks = (inode->i_size + sb->s_blocksize - 1) >>
260 sb->s_blocksize_bits;
261
262 /*
263 * we need to save the parent directory ID so that
264 * write_inode can update the directory information
265 * for this file. This will need special handling
266 * for cross-directory renames.
267 */
268 inode->u.adfs_i.parent_id = obj->parent_id;
269 inode->u.adfs_i.loadaddr = obj->loadaddr;
270 inode->u.adfs_i.execaddr = obj->execaddr;
271 inode->u.adfs_i.attr = obj->attr;
272 inode->u.adfs_i.stamped = ((obj->loadaddr & 0xfff00000) == 0xfff00000);
273
274 inode->i_mode = adfs_atts2mode(sb, inode);
275 inode->i_mtime =
276 inode->i_atime =
277 inode->i_ctime = adfs_adfs2unix_time(inode);
278
279 if (S_ISDIR(inode->i_mode)) {
280 inode->i_op = &adfs_dir_inode_operations;
281 inode->i_fop = &adfs_dir_operations;
282 } else if (S_ISREG(inode->i_mode)) {
283 inode->i_op = &adfs_file_inode_operations;
284 inode->i_fop = &adfs_file_operations;
285 inode->i_mapping->a_ops = &adfs_aops;
286 inode->u.adfs_i.mmu_private = inode->i_size;
287 }
288
289 insert_inode_hash(inode);
290
291 out:
292 return inode;
293 }
294
295 /*
296 * Validate and convert a changed access mode/time to their ADFS equivalents.
297 * adfs_write_inode will actually write the information back to the directory
298 * later.
299 */
300 int
301 adfs_notify_change(struct dentry *dentry, struct iattr *attr)
302 {
303 struct inode *inode = dentry->d_inode;
304 struct super_block *sb = inode->i_sb;
305 unsigned int ia_valid = attr->ia_valid;
306 int error;
307
308 error = inode_change_ok(inode, attr);
309
310 /*
311 * we can't change the UID or GID of any file -
312 * we have a global UID/GID in the superblock
313 */
314 if ((ia_valid & ATTR_UID && attr->ia_uid != sb->u.adfs_sb.s_uid) ||
315 (ia_valid & ATTR_GID && attr->ia_gid != sb->u.adfs_sb.s_gid))
316 error = -EPERM;
317
318 if (error)
319 goto out;
320
321 if (ia_valid & ATTR_SIZE)
322 vmtruncate(inode, attr->ia_size);
323 if (ia_valid & ATTR_MTIME) {
324 inode->i_mtime = attr->ia_mtime;
325 adfs_unix2adfs_time(inode, attr->ia_mtime);
326 }
327 /*
328 * FIXME: should we make these == to i_mtime since we don't
329 * have the ability to represent them in our filesystem?
330 */
331 if (ia_valid & ATTR_ATIME)
332 inode->i_atime = attr->ia_atime;
333 if (ia_valid & ATTR_CTIME)
334 inode->i_ctime = attr->ia_ctime;
335 if (ia_valid & ATTR_MODE) {
336 inode->u.adfs_i.attr = adfs_mode2atts(sb, inode);
337 inode->i_mode = adfs_atts2mode(sb, inode);
338 }
339
340 /*
341 * FIXME: should we be marking this inode dirty even if
342 * we don't have any metadata to write back?
343 */
344 if (ia_valid & (ATTR_SIZE | ATTR_MTIME | ATTR_MODE))
345 mark_inode_dirty(inode);
346 out:
347 return error;
348 }
349
350 /*
351 * write an existing inode back to the directory, and therefore the disk.
352 * The adfs-specific inode data has already been updated by
353 * adfs_notify_change()
354 */
355 void adfs_write_inode(struct inode *inode, int unused)
356 {
357 struct super_block *sb = inode->i_sb;
358 struct object_info obj;
359
360 lock_kernel();
361 obj.file_id = inode->i_ino;
362 obj.name_len = 0;
363 obj.parent_id = inode->u.adfs_i.parent_id;
364 obj.loadaddr = inode->u.adfs_i.loadaddr;
365 obj.execaddr = inode->u.adfs_i.execaddr;
366 obj.attr = inode->u.adfs_i.attr;
367 obj.size = inode->i_size;
368
369 adfs_dir_update(sb, &obj);
370 unlock_kernel();
371 }
372
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