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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/buffer_head.h> |
11 | #include <linux/writeback.h> |
12 | #include "adfs.h" |
13 | |
14 | /* |
15 | * Lookup/Create a block at offset 'block' into 'inode'. We currently do |
16 | * not support creation of new blocks, so we return -EIO for this case. |
17 | */ |
18 | static int |
19 | adfs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh, |
20 | int create) |
21 | { |
22 | if (!create) { |
23 | if (block >= inode->i_blocks) |
24 | goto abort_toobig; |
25 | |
26 | block = __adfs_block_map(inode->i_sb, inode->i_ino, block); |
27 | if (block) |
28 | map_bh(bh, inode->i_sb, block); |
29 | return 0; |
30 | } |
31 | /* don't support allocation of blocks yet */ |
32 | return -EIO; |
33 | |
34 | abort_toobig: |
35 | return 0; |
36 | } |
37 | |
38 | static int adfs_writepage(struct page *page, struct writeback_control *wbc) |
39 | { |
40 | return block_write_full_page(page, adfs_get_block, wbc); |
41 | } |
42 | |
43 | static int adfs_readpage(struct file *file, struct page *page) |
44 | { |
45 | return block_read_full_page(page, adfs_get_block); |
46 | } |
47 | |
48 | static int adfs_write_begin(struct file *file, struct address_space *mapping, |
49 | loff_t pos, unsigned len, unsigned flags, |
50 | struct page **pagep, void **fsdata) |
51 | { |
52 | int ret; |
53 | |
54 | *pagep = NULL; |
55 | ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata, |
56 | adfs_get_block, |
57 | &ADFS_I(mapping->host)->mmu_private); |
58 | if (unlikely(ret)) { |
59 | loff_t isize = mapping->host->i_size; |
60 | if (pos + len > isize) |
61 | vmtruncate(mapping->host, isize); |
62 | } |
63 | |
64 | return ret; |
65 | } |
66 | |
67 | static sector_t _adfs_bmap(struct address_space *mapping, sector_t block) |
68 | { |
69 | return generic_block_bmap(mapping, block, adfs_get_block); |
70 | } |
71 | |
72 | static const struct address_space_operations adfs_aops = { |
73 | .readpage = adfs_readpage, |
74 | .writepage = adfs_writepage, |
75 | .write_begin = adfs_write_begin, |
76 | .write_end = generic_write_end, |
77 | .bmap = _adfs_bmap |
78 | }; |
79 | |
80 | /* |
81 | * Convert ADFS attributes and filetype to Linux permission. |
82 | */ |
83 | static umode_t |
84 | adfs_atts2mode(struct super_block *sb, struct inode *inode) |
85 | { |
86 | unsigned int attr = ADFS_I(inode)->attr; |
87 | umode_t mode, rmask; |
88 | struct adfs_sb_info *asb = ADFS_SB(sb); |
89 | |
90 | if (attr & ADFS_NDA_DIRECTORY) { |
91 | mode = S_IRUGO & asb->s_owner_mask; |
92 | return S_IFDIR | S_IXUGO | mode; |
93 | } |
94 | |
95 | switch (ADFS_I(inode)->filetype) { |
96 | case 0xfc0: /* LinkFS */ |
97 | return S_IFLNK|S_IRWXUGO; |
98 | |
99 | case 0xfe6: /* UnixExec */ |
100 | rmask = S_IRUGO | S_IXUGO; |
101 | break; |
102 | |
103 | default: |
104 | rmask = S_IRUGO; |
105 | } |
106 | |
107 | mode = S_IFREG; |
108 | |
109 | if (attr & ADFS_NDA_OWNER_READ) |
110 | mode |= rmask & asb->s_owner_mask; |
111 | |
112 | if (attr & ADFS_NDA_OWNER_WRITE) |
113 | mode |= S_IWUGO & asb->s_owner_mask; |
114 | |
115 | if (attr & ADFS_NDA_PUBLIC_READ) |
116 | mode |= rmask & asb->s_other_mask; |
117 | |
118 | if (attr & ADFS_NDA_PUBLIC_WRITE) |
119 | mode |= S_IWUGO & asb->s_other_mask; |
120 | return mode; |
121 | } |
122 | |
123 | /* |
124 | * Convert Linux permission to ADFS attribute. We try to do the reverse |
125 | * of atts2mode, but there is not a 1:1 translation. |
126 | */ |
127 | static int |
128 | adfs_mode2atts(struct super_block *sb, struct inode *inode) |
129 | { |
130 | umode_t mode; |
131 | int attr; |
132 | struct adfs_sb_info *asb = ADFS_SB(sb); |
133 | |
134 | /* FIXME: should we be able to alter a link? */ |
135 | if (S_ISLNK(inode->i_mode)) |
136 | return ADFS_I(inode)->attr; |
137 | |
138 | if (S_ISDIR(inode->i_mode)) |
139 | attr = ADFS_NDA_DIRECTORY; |
140 | else |
141 | attr = 0; |
142 | |
143 | mode = inode->i_mode & asb->s_owner_mask; |
144 | if (mode & S_IRUGO) |
145 | attr |= ADFS_NDA_OWNER_READ; |
146 | if (mode & S_IWUGO) |
147 | attr |= ADFS_NDA_OWNER_WRITE; |
148 | |
149 | mode = inode->i_mode & asb->s_other_mask; |
150 | mode &= ~asb->s_owner_mask; |
151 | if (mode & S_IRUGO) |
152 | attr |= ADFS_NDA_PUBLIC_READ; |
153 | if (mode & S_IWUGO) |
154 | attr |= ADFS_NDA_PUBLIC_WRITE; |
155 | |
156 | return attr; |
157 | } |
158 | |
159 | /* |
160 | * Convert an ADFS time to Unix time. ADFS has a 40-bit centi-second time |
161 | * referenced to 1 Jan 1900 (til 2248) so we need to discard 2208988800 seconds |
162 | * of time to convert from RISC OS epoch to Unix epoch. |
163 | */ |
164 | static void |
165 | adfs_adfs2unix_time(struct timespec *tv, struct inode *inode) |
166 | { |
167 | unsigned int high, low; |
168 | /* 01 Jan 1970 00:00:00 (Unix epoch) as nanoseconds since |
169 | * 01 Jan 1900 00:00:00 (RISC OS epoch) |
170 | */ |
171 | static const s64 nsec_unix_epoch_diff_risc_os_epoch = |
172 | 2208988800000000000LL; |
173 | s64 nsec; |
174 | |
175 | if (ADFS_I(inode)->stamped == 0) |
176 | goto cur_time; |
177 | |
178 | high = ADFS_I(inode)->loadaddr & 0xFF; /* top 8 bits of timestamp */ |
179 | low = ADFS_I(inode)->execaddr; /* bottom 32 bits of timestamp */ |
180 | |
181 | /* convert 40-bit centi-seconds to 32-bit seconds |
182 | * going via nanoseconds to retain precision |
183 | */ |
184 | nsec = (((s64) high << 32) | (s64) low) * 10000000; /* cs to ns */ |
185 | |
186 | /* Files dated pre 01 Jan 1970 00:00:00. */ |
187 | if (nsec < nsec_unix_epoch_diff_risc_os_epoch) |
188 | goto too_early; |
189 | |
190 | /* convert from RISC OS to Unix epoch */ |
191 | nsec -= nsec_unix_epoch_diff_risc_os_epoch; |
192 | |
193 | *tv = ns_to_timespec(nsec); |
194 | return; |
195 | |
196 | cur_time: |
197 | *tv = CURRENT_TIME; |
198 | return; |
199 | |
200 | too_early: |
201 | tv->tv_sec = tv->tv_nsec = 0; |
202 | return; |
203 | } |
204 | |
205 | /* |
206 | * Convert an Unix time to ADFS time. We only do this if the entry has a |
207 | * time/date stamp already. |
208 | */ |
209 | static void |
210 | adfs_unix2adfs_time(struct inode *inode, unsigned int secs) |
211 | { |
212 | unsigned int high, low; |
213 | |
214 | if (ADFS_I(inode)->stamped) { |
215 | /* convert 32-bit seconds to 40-bit centi-seconds */ |
216 | low = (secs & 255) * 100; |
217 | high = (secs / 256) * 100 + (low >> 8) + 0x336e996a; |
218 | |
219 | ADFS_I(inode)->loadaddr = (high >> 24) | |
220 | (ADFS_I(inode)->loadaddr & ~0xff); |
221 | ADFS_I(inode)->execaddr = (low & 255) | (high << 8); |
222 | } |
223 | } |
224 | |
225 | /* |
226 | * Fill in the inode information from the object information. |
227 | * |
228 | * Note that this is an inode-less filesystem, so we can't use the inode |
229 | * number to reference the metadata on the media. Instead, we use the |
230 | * inode number to hold the object ID, which in turn will tell us where |
231 | * the data is held. We also save the parent object ID, and with these |
232 | * two, we can locate the metadata. |
233 | * |
234 | * This does mean that we rely on an objects parent remaining the same at |
235 | * all times - we cannot cope with a cross-directory rename (yet). |
236 | */ |
237 | struct inode * |
238 | adfs_iget(struct super_block *sb, struct object_info *obj) |
239 | { |
240 | struct inode *inode; |
241 | |
242 | inode = new_inode(sb); |
243 | if (!inode) |
244 | goto out; |
245 | |
246 | inode->i_uid = ADFS_SB(sb)->s_uid; |
247 | inode->i_gid = ADFS_SB(sb)->s_gid; |
248 | inode->i_ino = obj->file_id; |
249 | inode->i_size = obj->size; |
250 | inode->i_nlink = 2; |
251 | inode->i_blocks = (inode->i_size + sb->s_blocksize - 1) >> |
252 | sb->s_blocksize_bits; |
253 | |
254 | /* |
255 | * we need to save the parent directory ID so that |
256 | * write_inode can update the directory information |
257 | * for this file. This will need special handling |
258 | * for cross-directory renames. |
259 | */ |
260 | ADFS_I(inode)->parent_id = obj->parent_id; |
261 | ADFS_I(inode)->loadaddr = obj->loadaddr; |
262 | ADFS_I(inode)->execaddr = obj->execaddr; |
263 | ADFS_I(inode)->attr = obj->attr; |
264 | ADFS_I(inode)->filetype = obj->filetype; |
265 | ADFS_I(inode)->stamped = ((obj->loadaddr & 0xfff00000) == 0xfff00000); |
266 | |
267 | inode->i_mode = adfs_atts2mode(sb, inode); |
268 | adfs_adfs2unix_time(&inode->i_mtime, inode); |
269 | inode->i_atime = inode->i_mtime; |
270 | inode->i_ctime = inode->i_mtime; |
271 | |
272 | if (S_ISDIR(inode->i_mode)) { |
273 | inode->i_op = &adfs_dir_inode_operations; |
274 | inode->i_fop = &adfs_dir_operations; |
275 | } else if (S_ISREG(inode->i_mode)) { |
276 | inode->i_op = &adfs_file_inode_operations; |
277 | inode->i_fop = &adfs_file_operations; |
278 | inode->i_mapping->a_ops = &adfs_aops; |
279 | ADFS_I(inode)->mmu_private = inode->i_size; |
280 | } |
281 | |
282 | insert_inode_hash(inode); |
283 | |
284 | out: |
285 | return inode; |
286 | } |
287 | |
288 | /* |
289 | * Validate and convert a changed access mode/time to their ADFS equivalents. |
290 | * adfs_write_inode will actually write the information back to the directory |
291 | * later. |
292 | */ |
293 | int |
294 | adfs_notify_change(struct dentry *dentry, struct iattr *attr) |
295 | { |
296 | struct inode *inode = dentry->d_inode; |
297 | struct super_block *sb = inode->i_sb; |
298 | unsigned int ia_valid = attr->ia_valid; |
299 | int error; |
300 | |
301 | error = inode_change_ok(inode, attr); |
302 | |
303 | /* |
304 | * we can't change the UID or GID of any file - |
305 | * we have a global UID/GID in the superblock |
306 | */ |
307 | if ((ia_valid & ATTR_UID && attr->ia_uid != ADFS_SB(sb)->s_uid) || |
308 | (ia_valid & ATTR_GID && attr->ia_gid != ADFS_SB(sb)->s_gid)) |
309 | error = -EPERM; |
310 | |
311 | if (error) |
312 | goto out; |
313 | |
314 | /* XXX: this is missing some actual on-disk truncation.. */ |
315 | if (ia_valid & ATTR_SIZE) |
316 | truncate_setsize(inode, attr->ia_size); |
317 | |
318 | if (ia_valid & ATTR_MTIME) { |
319 | inode->i_mtime = attr->ia_mtime; |
320 | adfs_unix2adfs_time(inode, attr->ia_mtime.tv_sec); |
321 | } |
322 | /* |
323 | * FIXME: should we make these == to i_mtime since we don't |
324 | * have the ability to represent them in our filesystem? |
325 | */ |
326 | if (ia_valid & ATTR_ATIME) |
327 | inode->i_atime = attr->ia_atime; |
328 | if (ia_valid & ATTR_CTIME) |
329 | inode->i_ctime = attr->ia_ctime; |
330 | if (ia_valid & ATTR_MODE) { |
331 | ADFS_I(inode)->attr = adfs_mode2atts(sb, inode); |
332 | inode->i_mode = adfs_atts2mode(sb, inode); |
333 | } |
334 | |
335 | /* |
336 | * FIXME: should we be marking this inode dirty even if |
337 | * we don't have any metadata to write back? |
338 | */ |
339 | if (ia_valid & (ATTR_SIZE | ATTR_MTIME | ATTR_MODE)) |
340 | mark_inode_dirty(inode); |
341 | out: |
342 | return error; |
343 | } |
344 | |
345 | /* |
346 | * write an existing inode back to the directory, and therefore the disk. |
347 | * The adfs-specific inode data has already been updated by |
348 | * adfs_notify_change() |
349 | */ |
350 | int adfs_write_inode(struct inode *inode, struct writeback_control *wbc) |
351 | { |
352 | struct super_block *sb = inode->i_sb; |
353 | struct object_info obj; |
354 | int ret; |
355 | |
356 | obj.file_id = inode->i_ino; |
357 | obj.name_len = 0; |
358 | obj.parent_id = ADFS_I(inode)->parent_id; |
359 | obj.loadaddr = ADFS_I(inode)->loadaddr; |
360 | obj.execaddr = ADFS_I(inode)->execaddr; |
361 | obj.attr = ADFS_I(inode)->attr; |
362 | obj.size = inode->i_size; |
363 | |
364 | ret = adfs_dir_update(sb, &obj, wbc->sync_mode == WB_SYNC_ALL); |
365 | return ret; |
366 | } |
367 |
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