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 */
27static int
28adfs_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
46abort_negative:
47	adfs_error(inode->i_sb, "block %d < 0", block);
48	return -EIO;
49
50abort_toobig:
51	return 0;
52}
53
54static int adfs_writepage(struct page *page, struct writeback_control *wbc)
55{
56	return block_write_full_page(page, adfs_get_block, wbc);
57}
58
59static int adfs_readpage(struct file *file, struct page *page)
60{
61	return block_read_full_page(page, adfs_get_block);
62}
63
64static 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
70static sector_t _adfs_bmap(struct address_space *mapping, sector_t block)
71{
72	return generic_block_bmap(mapping, block, adfs_get_block);
73}
74
75static 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
84static inline unsigned int
85adfs_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 */
100static umode_t
101adfs_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 */
146static int
147adfs_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	if (S_ISLNK(inode->i_mode))
154		return ADFS_I(inode)->attr;
155
156	if (S_ISDIR(inode->i_mode))
157		attr = ADFS_NDA_DIRECTORY;
158	else
159		attr = 0;
160
161	mode = inode->i_mode & asb->s_owner_mask;
162	if (mode & S_IRUGO)
163		attr |= ADFS_NDA_OWNER_READ;
164	if (mode & S_IWUGO)
165		attr |= ADFS_NDA_OWNER_WRITE;
166
167	mode = inode->i_mode & asb->s_other_mask;
168	mode &= ~asb->s_owner_mask;
169	if (mode & S_IRUGO)
170		attr |= ADFS_NDA_PUBLIC_READ;
171	if (mode & S_IWUGO)
172		attr |= ADFS_NDA_PUBLIC_WRITE;
173
174	return attr;
175}
176
177/*
178 * Convert an ADFS time to Unix time.  ADFS has a 40-bit centi-second time
179 * referenced to 1 Jan 1900 (til 2248)
180 */
181static void
182adfs_adfs2unix_time(struct timespec *tv, struct inode *inode)
183{
184	unsigned int high, low;
185
186	if (ADFS_I(inode)->stamped == 0)
187		goto cur_time;
188
189	high = ADFS_I(inode)->loadaddr << 24;
190	low  = ADFS_I(inode)->execaddr;
191
192	high |= low >> 8;
193	low  &= 255;
194
195	/* Files dated pre  01 Jan 1970 00:00:00. */
196	if (high < 0x336e996a)
197		goto too_early;
198
199	/* Files dated post 18 Jan 2038 03:14:05. */
200	if (high >= 0x656e9969)
201		goto too_late;
202
203	/* discard 2208988800 (0x336e996a00) seconds of time */
204	high -= 0x336e996a;
205
206	/* convert 40-bit centi-seconds to 32-bit seconds */
207	tv->tv_sec = (((high % 100) << 8) + low) / 100 + (high / 100 << 8);
208	tv->tv_nsec = 0;
209	return;
210
211 cur_time:
212	*tv = CURRENT_TIME_SEC;
213	return;
214
215 too_early:
216	tv->tv_sec = tv->tv_nsec = 0;
217	return;
218
219 too_late:
220	tv->tv_sec = 0x7ffffffd;
221	tv->tv_nsec = 0;
222	return;
223}
224
225/*
226 * Convert an Unix time to ADFS time.  We only do this if the entry has a
227 * time/date stamp already.
228 */
229static void
230adfs_unix2adfs_time(struct inode *inode, unsigned int secs)
231{
232	unsigned int high, low;
233
234	if (ADFS_I(inode)->stamped) {
235		/* convert 32-bit seconds to 40-bit centi-seconds */
236		low  = (secs & 255) * 100;
237		high = (secs / 256) * 100 + (low >> 8) + 0x336e996a;
238
239		ADFS_I(inode)->loadaddr = (high >> 24) |
240				(ADFS_I(inode)->loadaddr & ~0xff);
241		ADFS_I(inode)->execaddr = (low & 255) | (high << 8);
242	}
243}
244
245/*
246 * Fill in the inode information from the object information.
247 *
248 * Note that this is an inode-less filesystem, so we can't use the inode
249 * number to reference the metadata on the media.  Instead, we use the
250 * inode number to hold the object ID, which in turn will tell us where
251 * the data is held.  We also save the parent object ID, and with these
252 * two, we can locate the metadata.
253 *
254 * This does mean that we rely on an objects parent remaining the same at
255 * all times - we cannot cope with a cross-directory rename (yet).
256 */
257struct inode *
258adfs_iget(struct super_block *sb, struct object_info *obj)
259{
260	struct inode *inode;
261
262	inode = new_inode(sb);
263	if (!inode)
264		goto out;
265
266	inode->i_uid	 = ADFS_SB(sb)->s_uid;
267	inode->i_gid	 = ADFS_SB(sb)->s_gid;
268	inode->i_ino	 = obj->file_id;
269	inode->i_size	 = obj->size;
270	inode->i_nlink	 = 2;
271	inode->i_blocks	 = (inode->i_size + sb->s_blocksize - 1) >>
272			    sb->s_blocksize_bits;
273
274	/*
275	 * we need to save the parent directory ID so that
276	 * write_inode can update the directory information
277	 * for this file.  This will need special handling
278	 * for cross-directory renames.
279	 */
280	ADFS_I(inode)->parent_id = obj->parent_id;
281	ADFS_I(inode)->loadaddr  = obj->loadaddr;
282	ADFS_I(inode)->execaddr  = obj->execaddr;
283	ADFS_I(inode)->attr      = obj->attr;
284	ADFS_I(inode)->stamped	  = ((obj->loadaddr & 0xfff00000) == 0xfff00000);
285
286	inode->i_mode	 = adfs_atts2mode(sb, inode);
287	adfs_adfs2unix_time(&inode->i_mtime, inode);
288	inode->i_atime = inode->i_mtime;
289	inode->i_ctime = inode->i_mtime;
290
291	if (S_ISDIR(inode->i_mode)) {
292		inode->i_op	= &adfs_dir_inode_operations;
293		inode->i_fop	= &adfs_dir_operations;
294	} else if (S_ISREG(inode->i_mode)) {
295		inode->i_op	= &adfs_file_inode_operations;
296		inode->i_fop	= &adfs_file_operations;
297		inode->i_mapping->a_ops = &adfs_aops;
298		ADFS_I(inode)->mmu_private = inode->i_size;
299	}
300
301	insert_inode_hash(inode);
302
303out:
304	return inode;
305}
306
307/*
308 * Validate and convert a changed access mode/time to their ADFS equivalents.
309 * adfs_write_inode will actually write the information back to the directory
310 * later.
311 */
312int
313adfs_notify_change(struct dentry *dentry, struct iattr *attr)
314{
315	struct inode *inode = dentry->d_inode;
316	struct super_block *sb = inode->i_sb;
317	unsigned int ia_valid = attr->ia_valid;
318	int error;
319
320	lock_kernel();
321
322	error = inode_change_ok(inode, attr);
323
324	/*
325	 * we can't change the UID or GID of any file -
326	 * we have a global UID/GID in the superblock
327	 */
328	if ((ia_valid & ATTR_UID && attr->ia_uid != ADFS_SB(sb)->s_uid) ||
329	    (ia_valid & ATTR_GID && attr->ia_gid != ADFS_SB(sb)->s_gid))
330		error = -EPERM;
331
332	if (error)
333		goto out;
334
335	if (ia_valid & ATTR_SIZE)
336		error = vmtruncate(inode, attr->ia_size);
337
338	if (error)
339		goto out;
340
341	if (ia_valid & ATTR_MTIME) {
342		inode->i_mtime = attr->ia_mtime;
343		adfs_unix2adfs_time(inode, attr->ia_mtime.tv_sec);
344	}
345	if (ia_valid & ATTR_ATIME)
346		inode->i_atime = attr->ia_atime;
347	if (ia_valid & ATTR_CTIME)
348		inode->i_ctime = attr->ia_ctime;
349	if (ia_valid & ATTR_MODE) {
350		ADFS_I(inode)->attr = adfs_mode2atts(sb, inode);
351		inode->i_mode = adfs_atts2mode(sb, inode);
352	}
353
354	if (ia_valid & (ATTR_SIZE | ATTR_MTIME | ATTR_MODE))
355		mark_inode_dirty(inode);
356out:
357	unlock_kernel();
358	return error;
359}
360
361/*
362 * write an existing inode back to the directory, and therefore the disk.
363 * The adfs-specific inode data has already been updated by
364 * adfs_notify_change()
365 */
366int adfs_write_inode(struct inode *inode, int unused)
367{
368	struct super_block *sb = inode->i_sb;
369	struct object_info obj;
370	int ret;
371
372	lock_kernel();
373	obj.file_id	= inode->i_ino;
374	obj.name_len	= 0;
375	obj.parent_id	= ADFS_I(inode)->parent_id;
376	obj.loadaddr	= ADFS_I(inode)->loadaddr;
377	obj.execaddr	= ADFS_I(inode)->execaddr;
378	obj.attr	= ADFS_I(inode)->attr;
379	obj.size	= inode->i_size;
380
381	ret = adfs_dir_update(sb, &obj);
382	unlock_kernel();
383	return ret;
384}
385MODULE_LICENSE("GPL");
386