xref: /openbmc/linux/fs/adfs/inode.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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_prepare_write(struct file *file, struct page *page, unsigned int from, unsigned int to)
65 {
66 	return cont_prepare_write(page, from, to, adfs_get_block,
67 		&ADFS_I(page->mapping->host)->mmu_private);
68 }
69 
70 static sector_t _adfs_bmap(struct address_space *mapping, sector_t block)
71 {
72 	return generic_block_bmap(mapping, block, adfs_get_block);
73 }
74 
75 static const struct address_space_operations adfs_aops = {
76 	.readpage	= adfs_readpage,
77 	.writepage	= adfs_writepage,
78 	.sync_page	= block_sync_page,
79 	.prepare_write	= adfs_prepare_write,
80 	.commit_write	= generic_commit_write,
81 	.bmap		= _adfs_bmap
82 };
83 
84 static inline unsigned int
85 adfs_filetype(struct inode *inode)
86 {
87 	unsigned int type;
88 
89 	if (ADFS_I(inode)->stamped)
90 		type = (ADFS_I(inode)->loadaddr >> 8) & 0xfff;
91 	else
92 		type = (unsigned int) -1;
93 
94 	return type;
95 }
96 
97 /*
98  * Convert ADFS attributes and filetype to Linux permission.
99  */
100 static umode_t
101 adfs_atts2mode(struct super_block *sb, struct inode *inode)
102 {
103 	unsigned int filetype, attr = ADFS_I(inode)->attr;
104 	umode_t mode, rmask;
105 	struct adfs_sb_info *asb = ADFS_SB(sb);
106 
107 	if (attr & ADFS_NDA_DIRECTORY) {
108 		mode = S_IRUGO & asb->s_owner_mask;
109 		return S_IFDIR | S_IXUGO | mode;
110 	}
111 
112 	filetype = adfs_filetype(inode);
113 
114 	switch (filetype) {
115 	case 0xfc0:	/* LinkFS */
116 		return S_IFLNK|S_IRWXUGO;
117 
118 	case 0xfe6:	/* UnixExec */
119 		rmask = S_IRUGO | S_IXUGO;
120 		break;
121 
122 	default:
123 		rmask = S_IRUGO;
124 	}
125 
126 	mode = S_IFREG;
127 
128 	if (attr & ADFS_NDA_OWNER_READ)
129 		mode |= rmask & asb->s_owner_mask;
130 
131 	if (attr & ADFS_NDA_OWNER_WRITE)
132 		mode |= S_IWUGO & asb->s_owner_mask;
133 
134 	if (attr & ADFS_NDA_PUBLIC_READ)
135 		mode |= rmask & asb->s_other_mask;
136 
137 	if (attr & ADFS_NDA_PUBLIC_WRITE)
138 		mode |= S_IWUGO & asb->s_other_mask;
139 	return mode;
140 }
141 
142 /*
143  * Convert Linux permission to ADFS attribute.  We try to do the reverse
144  * of atts2mode, but there is not a 1:1 translation.
145  */
146 static int
147 adfs_mode2atts(struct super_block *sb, struct inode *inode)
148 {
149 	umode_t mode;
150 	int attr;
151 	struct adfs_sb_info *asb = ADFS_SB(sb);
152 
153 	/* FIXME: should we be able to alter a link? */
154 	if (S_ISLNK(inode->i_mode))
155 		return ADFS_I(inode)->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 & asb->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 & asb->s_other_mask;
169 	mode &= ~asb->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 void
183 adfs_adfs2unix_time(struct timespec *tv, struct inode *inode)
184 {
185 	unsigned int high, low;
186 
187 	if (ADFS_I(inode)->stamped == 0)
188 		goto cur_time;
189 
190 	high = ADFS_I(inode)->loadaddr << 24;
191 	low  = ADFS_I(inode)->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 		goto too_early;
199 
200 	/* Files dated post 18 Jan 2038 03:14:05. */
201 	if (high >= 0x656e9969)
202 		goto too_late;
203 
204 	/* discard 2208988800 (0x336e996a00) seconds of time */
205 	high -= 0x336e996a;
206 
207 	/* convert 40-bit centi-seconds to 32-bit seconds */
208 	tv->tv_sec = (((high % 100) << 8) + low) / 100 + (high / 100 << 8);
209 	tv->tv_nsec = 0;
210 	return;
211 
212  cur_time:
213 	*tv = CURRENT_TIME_SEC;
214 	return;
215 
216  too_early:
217 	tv->tv_sec = tv->tv_nsec = 0;
218 	return;
219 
220  too_late:
221 	tv->tv_sec = 0x7ffffffd;
222 	tv->tv_nsec = 0;
223 	return;
224 }
225 
226 /*
227  * Convert an Unix time to ADFS time.  We only do this if the entry has a
228  * time/date stamp already.
229  */
230 static void
231 adfs_unix2adfs_time(struct inode *inode, unsigned int secs)
232 {
233 	unsigned int high, low;
234 
235 	if (ADFS_I(inode)->stamped) {
236 		/* convert 32-bit seconds to 40-bit centi-seconds */
237 		low  = (secs & 255) * 100;
238 		high = (secs / 256) * 100 + (low >> 8) + 0x336e996a;
239 
240 		ADFS_I(inode)->loadaddr = (high >> 24) |
241 				(ADFS_I(inode)->loadaddr & ~0xff);
242 		ADFS_I(inode)->execaddr = (low & 255) | (high << 8);
243 	}
244 }
245 
246 /*
247  * Fill in the inode information from the object information.
248  *
249  * Note that this is an inode-less filesystem, so we can't use the inode
250  * number to reference the metadata on the media.  Instead, we use the
251  * inode number to hold the object ID, which in turn will tell us where
252  * the data is held.  We also save the parent object ID, and with these
253  * two, we can locate the metadata.
254  *
255  * This does mean that we rely on an objects parent remaining the same at
256  * all times - we cannot cope with a cross-directory rename (yet).
257  */
258 struct inode *
259 adfs_iget(struct super_block *sb, struct object_info *obj)
260 {
261 	struct inode *inode;
262 
263 	inode = new_inode(sb);
264 	if (!inode)
265 		goto out;
266 
267 	inode->i_uid	 = ADFS_SB(sb)->s_uid;
268 	inode->i_gid	 = ADFS_SB(sb)->s_gid;
269 	inode->i_ino	 = obj->file_id;
270 	inode->i_size	 = obj->size;
271 	inode->i_nlink	 = 2;
272 	inode->i_blocks	 = (inode->i_size + sb->s_blocksize - 1) >>
273 			    sb->s_blocksize_bits;
274 
275 	/*
276 	 * we need to save the parent directory ID so that
277 	 * write_inode can update the directory information
278 	 * for this file.  This will need special handling
279 	 * for cross-directory renames.
280 	 */
281 	ADFS_I(inode)->parent_id = obj->parent_id;
282 	ADFS_I(inode)->loadaddr  = obj->loadaddr;
283 	ADFS_I(inode)->execaddr  = obj->execaddr;
284 	ADFS_I(inode)->attr      = obj->attr;
285 	ADFS_I(inode)->stamped	  = ((obj->loadaddr & 0xfff00000) == 0xfff00000);
286 
287 	inode->i_mode	 = adfs_atts2mode(sb, inode);
288 	adfs_adfs2unix_time(&inode->i_mtime, inode);
289 	inode->i_atime = inode->i_mtime;
290 	inode->i_ctime = inode->i_mtime;
291 
292 	if (S_ISDIR(inode->i_mode)) {
293 		inode->i_op	= &adfs_dir_inode_operations;
294 		inode->i_fop	= &adfs_dir_operations;
295 	} else if (S_ISREG(inode->i_mode)) {
296 		inode->i_op	= &adfs_file_inode_operations;
297 		inode->i_fop	= &adfs_file_operations;
298 		inode->i_mapping->a_ops = &adfs_aops;
299 		ADFS_I(inode)->mmu_private = inode->i_size;
300 	}
301 
302 	insert_inode_hash(inode);
303 
304 out:
305 	return inode;
306 }
307 
308 /*
309  * Validate and convert a changed access mode/time to their ADFS equivalents.
310  * adfs_write_inode will actually write the information back to the directory
311  * later.
312  */
313 int
314 adfs_notify_change(struct dentry *dentry, struct iattr *attr)
315 {
316 	struct inode *inode = dentry->d_inode;
317 	struct super_block *sb = inode->i_sb;
318 	unsigned int ia_valid = attr->ia_valid;
319 	int error;
320 
321 	lock_kernel();
322 
323 	error = inode_change_ok(inode, attr);
324 
325 	/*
326 	 * we can't change the UID or GID of any file -
327 	 * we have a global UID/GID in the superblock
328 	 */
329 	if ((ia_valid & ATTR_UID && attr->ia_uid != ADFS_SB(sb)->s_uid) ||
330 	    (ia_valid & ATTR_GID && attr->ia_gid != ADFS_SB(sb)->s_gid))
331 		error = -EPERM;
332 
333 	if (error)
334 		goto out;
335 
336 	if (ia_valid & ATTR_SIZE)
337 		error = vmtruncate(inode, attr->ia_size);
338 
339 	if (error)
340 		goto out;
341 
342 	if (ia_valid & ATTR_MTIME) {
343 		inode->i_mtime = attr->ia_mtime;
344 		adfs_unix2adfs_time(inode, attr->ia_mtime.tv_sec);
345 	}
346 	/*
347 	 * FIXME: should we make these == to i_mtime since we don't
348 	 * have the ability to represent them in our filesystem?
349 	 */
350 	if (ia_valid & ATTR_ATIME)
351 		inode->i_atime = attr->ia_atime;
352 	if (ia_valid & ATTR_CTIME)
353 		inode->i_ctime = attr->ia_ctime;
354 	if (ia_valid & ATTR_MODE) {
355 		ADFS_I(inode)->attr = adfs_mode2atts(sb, inode);
356 		inode->i_mode = adfs_atts2mode(sb, inode);
357 	}
358 
359 	/*
360 	 * FIXME: should we be marking this inode dirty even if
361 	 * we don't have any metadata to write back?
362 	 */
363 	if (ia_valid & (ATTR_SIZE | ATTR_MTIME | ATTR_MODE))
364 		mark_inode_dirty(inode);
365 out:
366 	unlock_kernel();
367 	return error;
368 }
369 
370 /*
371  * write an existing inode back to the directory, and therefore the disk.
372  * The adfs-specific inode data has already been updated by
373  * adfs_notify_change()
374  */
375 int adfs_write_inode(struct inode *inode, int unused)
376 {
377 	struct super_block *sb = inode->i_sb;
378 	struct object_info obj;
379 	int ret;
380 
381 	lock_kernel();
382 	obj.file_id	= inode->i_ino;
383 	obj.name_len	= 0;
384 	obj.parent_id	= ADFS_I(inode)->parent_id;
385 	obj.loadaddr	= ADFS_I(inode)->loadaddr;
386 	obj.execaddr	= ADFS_I(inode)->execaddr;
387 	obj.attr	= ADFS_I(inode)->attr;
388 	obj.size	= inode->i_size;
389 
390 	ret = adfs_dir_update(sb, &obj);
391 	unlock_kernel();
392 	return ret;
393 }
394 MODULE_LICENSE("GPL");
395