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/errno.h>
11 #include <linux/fs.h>
12 #include <linux/adfs_fs.h>
13 #include <linux/time.h>
14 #include <linux/stat.h>
15 #include <linux/string.h>
16 #include <linux/mm.h>
17 #include <linux/smp_lock.h>
18 #include <linux/module.h>
19 #include <linux/buffer_head.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 static int
28 adfs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh,
29 int create)
30 {
31 if (block < 0)
32 goto abort_negative;
33
34 if (!create) {
35 if (block >= inode->i_blocks)
36 goto abort_toobig;
37
38 block = __adfs_block_map(inode->i_sb, inode->i_ino, block);
39 if (block)
40 map_bh(bh, inode->i_sb, block);
41 return 0;
42 }
43 /* don't support allocation of blocks yet */
44 return -EIO;
45
46 abort_negative:
47 adfs_error(inode->i_sb, "block %d < 0", block);
48 return -EIO;
49
50 abort_toobig:
51 return 0;
52 }
53
54 static int adfs_writepage(struct page *page, struct writeback_control *wbc)
55 {
56 return block_write_full_page(page, adfs_get_block, wbc);
57 }
58
59 static int adfs_readpage(struct file *file, struct page *page)
60 {
61 return block_read_full_page(page, adfs_get_block);
62 }
63
64 static int adfs_write_begin(struct file *file, struct address_space *mapping,
65 loff_t pos, unsigned len, unsigned flags,
66 struct page **pagep, void **fsdata)
67 {
68 *pagep = NULL;
69 return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
70 adfs_get_block,
71 &ADFS_I(mapping->host)->mmu_private);
72 }
73
74 static sector_t _adfs_bmap(struct address_space *mapping, sector_t block)
75 {
76 return generic_block_bmap(mapping, block, adfs_get_block);
77 }
78
79 static const struct address_space_operations adfs_aops = {
80 .readpage = adfs_readpage,
81 .writepage = adfs_writepage,
82 .sync_page = block_sync_page,
83 .write_begin = adfs_write_begin,
84 .write_end = generic_write_end,
85 .bmap = _adfs_bmap
86 };
87
88 static inline unsigned int
89 adfs_filetype(struct inode *inode)
90 {
91 unsigned int type;
92
93 if (ADFS_I(inode)->stamped)
94 type = (ADFS_I(inode)->loadaddr >> 8) & 0xfff;
95 else
96 type = (unsigned int) -1;
97
98 return type;
99 }
100
101 /*
102 * Convert ADFS attributes and filetype to Linux permission.
103 */
104 static umode_t
105 adfs_atts2mode(struct super_block *sb, struct inode *inode)
106 {
107 unsigned int filetype, attr = ADFS_I(inode)->attr;
108 umode_t mode, rmask;
109 struct adfs_sb_info *asb = ADFS_SB(sb);
110
111 if (attr & ADFS_NDA_DIRECTORY) {
112 mode = S_IRUGO & asb->s_owner_mask;
113 return S_IFDIR | S_IXUGO | mode;
114 }
115
116 filetype = adfs_filetype(inode);
117
118 switch (filetype) {
119 case 0xfc0: /* LinkFS */
120 return S_IFLNK|S_IRWXUGO;
121
122 case 0xfe6: /* UnixExec */
123 rmask = S_IRUGO | S_IXUGO;
124 break;
125
126 default:
127 rmask = S_IRUGO;
128 }
129
130 mode = S_IFREG;
131
132 if (attr & ADFS_NDA_OWNER_READ)
133 mode |= rmask & asb->s_owner_mask;
134
135 if (attr & ADFS_NDA_OWNER_WRITE)
136 mode |= S_IWUGO & asb->s_owner_mask;
137
138 if (attr & ADFS_NDA_PUBLIC_READ)
139 mode |= rmask & asb->s_other_mask;
140
141 if (attr & ADFS_NDA_PUBLIC_WRITE)
142 mode |= S_IWUGO & asb->s_other_mask;
143 return mode;
144 }
145
146 /*
147 * Convert Linux permission to ADFS attribute. We try to do the reverse
148 * of atts2mode, but there is not a 1:1 translation.
149 */
150 static int
151 adfs_mode2atts(struct super_block *sb, struct inode *inode)
152 {
153 umode_t mode;
154 int attr;
155 struct adfs_sb_info *asb = ADFS_SB(sb);
156
157 /* FIXME: should we be able to alter a link? */
158 if (S_ISLNK(inode->i_mode))
159 return ADFS_I(inode)->attr;
160
161 if (S_ISDIR(inode->i_mode))
162 attr = ADFS_NDA_DIRECTORY;
163 else
164 attr = 0;
165
166 mode = inode->i_mode & asb->s_owner_mask;
167 if (mode & S_IRUGO)
168 attr |= ADFS_NDA_OWNER_READ;
169 if (mode & S_IWUGO)
170 attr |= ADFS_NDA_OWNER_WRITE;
171
172 mode = inode->i_mode & asb->s_other_mask;
173 mode &= ~asb->s_owner_mask;
174 if (mode & S_IRUGO)
175 attr |= ADFS_NDA_PUBLIC_READ;
176 if (mode & S_IWUGO)
177 attr |= ADFS_NDA_PUBLIC_WRITE;
178
179 return attr;
180 }
181
182 /*
183 * Convert an ADFS time to Unix time. ADFS has a 40-bit centi-second time
184 * referenced to 1 Jan 1900 (til 2248)
185 */
186 static void
187 adfs_adfs2unix_time(struct timespec *tv, struct inode *inode)
188 {
189 unsigned int high, low;
190
191 if (ADFS_I(inode)->stamped == 0)
192 goto cur_time;
193
194 high = ADFS_I(inode)->loadaddr << 24;
195 low = ADFS_I(inode)->execaddr;
196
197 high |= low >> 8;
198 low &= 255;
199
200 /* Files dated pre 01 Jan 1970 00:00:00. */
201 if (high < 0x336e996a)
202 goto too_early;
203
204 /* Files dated post 18 Jan 2038 03:14:05. */
205 if (high >= 0x656e9969)
206 goto too_late;
207
208 /* discard 2208988800 (0x336e996a00) seconds of time */
209 high -= 0x336e996a;
210
211 /* convert 40-bit centi-seconds to 32-bit seconds */
212 tv->tv_sec = (((high % 100) << 8) + low) / 100 + (high / 100 << 8);
213 tv->tv_nsec = 0;
214 return;
215
216 cur_time:
217 *tv = CURRENT_TIME_SEC;
218 return;
219
220 too_early:
221 tv->tv_sec = tv->tv_nsec = 0;
222 return;
223
224 too_late:
225 tv->tv_sec = 0x7ffffffd;
226 tv->tv_nsec = 0;
227 return;
228 }
229
230 /*
231 * Convert an Unix time to ADFS time. We only do this if the entry has a
232 * time/date stamp already.
233 */
234 static void
235 adfs_unix2adfs_time(struct inode *inode, unsigned int secs)
236 {
237 unsigned int high, low;
238
239 if (ADFS_I(inode)->stamped) {
240 /* convert 32-bit seconds to 40-bit centi-seconds */
241 low = (secs & 255) * 100;
242 high = (secs / 256) * 100 + (low >> 8) + 0x336e996a;
243
244 ADFS_I(inode)->loadaddr = (high >> 24) |
245 (ADFS_I(inode)->loadaddr & ~0xff);
246 ADFS_I(inode)->execaddr = (low & 255) | (high << 8);
247 }
248 }
249
250 /*
251 * Fill in the inode information from the object information.
252 *
253 * Note that this is an inode-less filesystem, so we can't use the inode
254 * number to reference the metadata on the media. Instead, we use the
255 * inode number to hold the object ID, which in turn will tell us where
256 * the data is held. We also save the parent object ID, and with these
257 * two, we can locate the metadata.
258 *
259 * This does mean that we rely on an objects parent remaining the same at
260 * all times - we cannot cope with a cross-directory rename (yet).
261 */
262 struct inode *
263 adfs_iget(struct super_block *sb, struct object_info *obj)
264 {
265 struct inode *inode;
266
267 inode = new_inode(sb);
268 if (!inode)
269 goto out;
270
271 inode->i_uid = ADFS_SB(sb)->s_uid;
272 inode->i_gid = ADFS_SB(sb)->s_gid;
273 inode->i_ino = obj->file_id;
274 inode->i_size = obj->size;
275 inode->i_nlink = 2;
276 inode->i_blocks = (inode->i_size + sb->s_blocksize - 1) >>
277 sb->s_blocksize_bits;
278
279 /*
280 * we need to save the parent directory ID so that
281 * write_inode can update the directory information
282 * for this file. This will need special handling
283 * for cross-directory renames.
284 */
285 ADFS_I(inode)->parent_id = obj->parent_id;
286 ADFS_I(inode)->loadaddr = obj->loadaddr;
287 ADFS_I(inode)->execaddr = obj->execaddr;
288 ADFS_I(inode)->attr = obj->attr;
289 ADFS_I(inode)->stamped = ((obj->loadaddr & 0xfff00000) == 0xfff00000);
290
291 inode->i_mode = adfs_atts2mode(sb, inode);
292 adfs_adfs2unix_time(&inode->i_mtime, inode);
293 inode->i_atime = inode->i_mtime;
294 inode->i_ctime = inode->i_mtime;
295
296 if (S_ISDIR(inode->i_mode)) {
297 inode->i_op = &adfs_dir_inode_operations;
298 inode->i_fop = &adfs_dir_operations;
299 } else if (S_ISREG(inode->i_mode)) {
300 inode->i_op = &adfs_file_inode_operations;
301 inode->i_fop = &adfs_file_operations;
302 inode->i_mapping->a_ops = &adfs_aops;
303 ADFS_I(inode)->mmu_private = inode->i_size;
304 }
305
306 insert_inode_hash(inode);
307
308 out:
309 return inode;
310 }
311
312 /*
313 * Validate and convert a changed access mode/time to their ADFS equivalents.
314 * adfs_write_inode will actually write the information back to the directory
315 * later.
316 */
317 int
318 adfs_notify_change(struct dentry *dentry, struct iattr *attr)
319 {
320 struct inode *inode = dentry->d_inode;
321 struct super_block *sb = inode->i_sb;
322 unsigned int ia_valid = attr->ia_valid;
323 int error;
324
325 lock_kernel();
326
327 error = inode_change_ok(inode, attr);
328
329 /*
330 * we can't change the UID or GID of any file -
331 * we have a global UID/GID in the superblock
332 */
333 if ((ia_valid & ATTR_UID && attr->ia_uid != ADFS_SB(sb)->s_uid) ||
334 (ia_valid & ATTR_GID && attr->ia_gid != ADFS_SB(sb)->s_gid))
335 error = -EPERM;
336
337 if (error)
338 goto out;
339
340 if (ia_valid & ATTR_SIZE)
341 error = vmtruncate(inode, attr->ia_size);
342
343 if (error)
344 goto out;
345
346 if (ia_valid & ATTR_MTIME) {
347 inode->i_mtime = attr->ia_mtime;
348 adfs_unix2adfs_time(inode, attr->ia_mtime.tv_sec);
349 }
350 /*
351 * FIXME: should we make these == to i_mtime since we don't
352 * have the ability to represent them in our filesystem?
353 */
354 if (ia_valid & ATTR_ATIME)
355 inode->i_atime = attr->ia_atime;
356 if (ia_valid & ATTR_CTIME)
357 inode->i_ctime = attr->ia_ctime;
358 if (ia_valid & ATTR_MODE) {
359 ADFS_I(inode)->attr = adfs_mode2atts(sb, inode);
360 inode->i_mode = adfs_atts2mode(sb, inode);
361 }
362
363 /*
364 * FIXME: should we be marking this inode dirty even if
365 * we don't have any metadata to write back?
366 */
367 if (ia_valid & (ATTR_SIZE | ATTR_MTIME | ATTR_MODE))
368 mark_inode_dirty(inode);
369 out:
370 unlock_kernel();
371 return error;
372 }
373
374 /*
375 * write an existing inode back to the directory, and therefore the disk.
376 * The adfs-specific inode data has already been updated by
377 * adfs_notify_change()
378 */
379 int adfs_write_inode(struct inode *inode, int unused)
380 {
381 struct super_block *sb = inode->i_sb;
382 struct object_info obj;
383 int ret;
384
385 lock_kernel();
386 obj.file_id = inode->i_ino;
387 obj.name_len = 0;
388 obj.parent_id = ADFS_I(inode)->parent_id;
389 obj.loadaddr = ADFS_I(inode)->loadaddr;
390 obj.execaddr = ADFS_I(inode)->execaddr;
391 obj.attr = ADFS_I(inode)->attr;
392 obj.size = inode->i_size;
393
394 ret = adfs_dir_update(sb, &obj);
395 unlock_kernel();
396 return ret;
397 }
398 MODULE_LICENSE("GPL");
399
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