1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * linux/fs/adfs/inode.c |
4 | * |
5 | * Copyright (C) 1997-1999 Russell King |
6 | */ |
7 | #include <linux/buffer_head.h> |
8 | #include <linux/writeback.h> |
9 | #include "adfs.h" |
10 | |
11 | /* |
12 | * Lookup/Create a block at offset 'block' into 'inode'. We currently do |
13 | * not support creation of new blocks, so we return -EIO for this case. |
14 | */ |
15 | static int |
16 | adfs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh, |
17 | int create) |
18 | { |
19 | if (!create) { |
20 | if (block >= inode->i_blocks) |
21 | goto abort_toobig; |
22 | |
23 | block = __adfs_block_map(sb: inode->i_sb, indaddr: ADFS_I(inode)->indaddr, |
24 | block); |
25 | if (block) |
26 | map_bh(bh, sb: inode->i_sb, block); |
27 | return 0; |
28 | } |
29 | /* don't support allocation of blocks yet */ |
30 | return -EIO; |
31 | |
32 | abort_toobig: |
33 | return 0; |
34 | } |
35 | |
36 | static int adfs_writepage(struct page *page, struct writeback_control *wbc) |
37 | { |
38 | return block_write_full_page(page, get_block: adfs_get_block, wbc); |
39 | } |
40 | |
41 | static int adfs_read_folio(struct file *file, struct folio *folio) |
42 | { |
43 | return block_read_full_folio(folio, adfs_get_block); |
44 | } |
45 | |
46 | static void adfs_write_failed(struct address_space *mapping, loff_t to) |
47 | { |
48 | struct inode *inode = mapping->host; |
49 | |
50 | if (to > inode->i_size) |
51 | truncate_pagecache(inode, new: inode->i_size); |
52 | } |
53 | |
54 | static int adfs_write_begin(struct file *file, struct address_space *mapping, |
55 | loff_t pos, unsigned len, |
56 | struct page **pagep, void **fsdata) |
57 | { |
58 | int ret; |
59 | |
60 | *pagep = NULL; |
61 | ret = cont_write_begin(file, mapping, pos, len, pagep, fsdata, |
62 | adfs_get_block, |
63 | &ADFS_I(inode: mapping->host)->mmu_private); |
64 | if (unlikely(ret)) |
65 | adfs_write_failed(mapping, to: pos + len); |
66 | |
67 | return ret; |
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 | .dirty_folio = block_dirty_folio, |
77 | .invalidate_folio = block_invalidate_folio, |
78 | .read_folio = adfs_read_folio, |
79 | .writepage = adfs_writepage, |
80 | .write_begin = adfs_write_begin, |
81 | .write_end = generic_write_end, |
82 | .bmap = _adfs_bmap |
83 | }; |
84 | |
85 | /* |
86 | * Convert ADFS attributes and filetype to Linux permission. |
87 | */ |
88 | static umode_t |
89 | adfs_atts2mode(struct super_block *sb, struct inode *inode) |
90 | { |
91 | unsigned int attr = ADFS_I(inode)->attr; |
92 | umode_t mode, rmask; |
93 | struct adfs_sb_info *asb = ADFS_SB(sb); |
94 | |
95 | if (attr & ADFS_NDA_DIRECTORY) { |
96 | mode = S_IRUGO & asb->s_owner_mask; |
97 | return S_IFDIR | S_IXUGO | mode; |
98 | } |
99 | |
100 | switch (adfs_filetype(loadaddr: ADFS_I(inode)->loadaddr)) { |
101 | case 0xfc0: /* LinkFS */ |
102 | return S_IFLNK|S_IRWXUGO; |
103 | |
104 | case 0xfe6: /* UnixExec */ |
105 | rmask = S_IRUGO | S_IXUGO; |
106 | break; |
107 | |
108 | default: |
109 | rmask = S_IRUGO; |
110 | } |
111 | |
112 | mode = S_IFREG; |
113 | |
114 | if (attr & ADFS_NDA_OWNER_READ) |
115 | mode |= rmask & asb->s_owner_mask; |
116 | |
117 | if (attr & ADFS_NDA_OWNER_WRITE) |
118 | mode |= S_IWUGO & asb->s_owner_mask; |
119 | |
120 | if (attr & ADFS_NDA_PUBLIC_READ) |
121 | mode |= rmask & asb->s_other_mask; |
122 | |
123 | if (attr & ADFS_NDA_PUBLIC_WRITE) |
124 | mode |= S_IWUGO & asb->s_other_mask; |
125 | return mode; |
126 | } |
127 | |
128 | /* |
129 | * Convert Linux permission to ADFS attribute. We try to do the reverse |
130 | * of atts2mode, but there is not a 1:1 translation. |
131 | */ |
132 | static int adfs_mode2atts(struct super_block *sb, struct inode *inode, |
133 | umode_t ia_mode) |
134 | { |
135 | struct adfs_sb_info *asb = ADFS_SB(sb); |
136 | umode_t mode; |
137 | int attr; |
138 | |
139 | /* FIXME: should we be able to alter a link? */ |
140 | if (S_ISLNK(inode->i_mode)) |
141 | return ADFS_I(inode)->attr; |
142 | |
143 | /* Directories do not have read/write permissions on the media */ |
144 | if (S_ISDIR(inode->i_mode)) |
145 | return ADFS_NDA_DIRECTORY; |
146 | |
147 | attr = 0; |
148 | mode = ia_mode & asb->s_owner_mask; |
149 | if (mode & S_IRUGO) |
150 | attr |= ADFS_NDA_OWNER_READ; |
151 | if (mode & S_IWUGO) |
152 | attr |= ADFS_NDA_OWNER_WRITE; |
153 | |
154 | mode = ia_mode & asb->s_other_mask; |
155 | mode &= ~asb->s_owner_mask; |
156 | if (mode & S_IRUGO) |
157 | attr |= ADFS_NDA_PUBLIC_READ; |
158 | if (mode & S_IWUGO) |
159 | attr |= ADFS_NDA_PUBLIC_WRITE; |
160 | |
161 | return attr; |
162 | } |
163 | |
164 | static const s64 nsec_unix_epoch_diff_risc_os_epoch = 2208988800000000000LL; |
165 | |
166 | /* |
167 | * Convert an ADFS time to Unix time. ADFS has a 40-bit centi-second time |
168 | * referenced to 1 Jan 1900 (til 2248) so we need to discard 2208988800 seconds |
169 | * of time to convert from RISC OS epoch to Unix epoch. |
170 | */ |
171 | static void |
172 | adfs_adfs2unix_time(struct timespec64 *tv, struct inode *inode) |
173 | { |
174 | unsigned int high, low; |
175 | /* 01 Jan 1970 00:00:00 (Unix epoch) as nanoseconds since |
176 | * 01 Jan 1900 00:00:00 (RISC OS epoch) |
177 | */ |
178 | s64 nsec; |
179 | |
180 | if (!adfs_inode_is_stamped(inode)) |
181 | goto cur_time; |
182 | |
183 | high = ADFS_I(inode)->loadaddr & 0xFF; /* top 8 bits of timestamp */ |
184 | low = ADFS_I(inode)->execaddr; /* bottom 32 bits of timestamp */ |
185 | |
186 | /* convert 40-bit centi-seconds to 32-bit seconds |
187 | * going via nanoseconds to retain precision |
188 | */ |
189 | nsec = (((s64) high << 32) | (s64) low) * 10000000; /* cs to ns */ |
190 | |
191 | /* Files dated pre 01 Jan 1970 00:00:00. */ |
192 | if (nsec < nsec_unix_epoch_diff_risc_os_epoch) |
193 | goto too_early; |
194 | |
195 | /* convert from RISC OS to Unix epoch */ |
196 | nsec -= nsec_unix_epoch_diff_risc_os_epoch; |
197 | |
198 | *tv = ns_to_timespec64(nsec); |
199 | return; |
200 | |
201 | cur_time: |
202 | *tv = current_time(inode); |
203 | return; |
204 | |
205 | too_early: |
206 | tv->tv_sec = tv->tv_nsec = 0; |
207 | return; |
208 | } |
209 | |
210 | /* Convert an Unix time to ADFS time for an entry that is already stamped. */ |
211 | static void adfs_unix2adfs_time(struct inode *inode, |
212 | const struct timespec64 *ts) |
213 | { |
214 | s64 cs, nsec = timespec64_to_ns(ts); |
215 | |
216 | /* convert from Unix to RISC OS epoch */ |
217 | nsec += nsec_unix_epoch_diff_risc_os_epoch; |
218 | |
219 | /* convert from nanoseconds to centiseconds */ |
220 | cs = div_s64(dividend: nsec, divisor: 10000000); |
221 | |
222 | cs = clamp_t(s64, cs, 0, 0xffffffffff); |
223 | |
224 | ADFS_I(inode)->loadaddr &= ~0xff; |
225 | ADFS_I(inode)->loadaddr |= (cs >> 32) & 0xff; |
226 | ADFS_I(inode)->execaddr = cs; |
227 | } |
228 | |
229 | /* |
230 | * Fill in the inode information from the object information. |
231 | * |
232 | * Note that this is an inode-less filesystem, so we can't use the inode |
233 | * number to reference the metadata on the media. Instead, we use the |
234 | * inode number to hold the object ID, which in turn will tell us where |
235 | * the data is held. We also save the parent object ID, and with these |
236 | * two, we can locate the metadata. |
237 | * |
238 | * This does mean that we rely on an objects parent remaining the same at |
239 | * all times - we cannot cope with a cross-directory rename (yet). |
240 | */ |
241 | struct inode * |
242 | adfs_iget(struct super_block *sb, struct object_info *obj) |
243 | { |
244 | struct inode *inode; |
245 | struct timespec64 ts; |
246 | |
247 | inode = new_inode(sb); |
248 | if (!inode) |
249 | goto out; |
250 | |
251 | inode->i_uid = ADFS_SB(sb)->s_uid; |
252 | inode->i_gid = ADFS_SB(sb)->s_gid; |
253 | inode->i_ino = obj->indaddr; |
254 | inode->i_size = obj->size; |
255 | set_nlink(inode, nlink: 2); |
256 | inode->i_blocks = (inode->i_size + sb->s_blocksize - 1) >> |
257 | sb->s_blocksize_bits; |
258 | |
259 | /* |
260 | * we need to save the parent directory ID so that |
261 | * write_inode can update the directory information |
262 | * for this file. This will need special handling |
263 | * for cross-directory renames. |
264 | */ |
265 | ADFS_I(inode)->parent_id = obj->parent_id; |
266 | ADFS_I(inode)->indaddr = obj->indaddr; |
267 | ADFS_I(inode)->loadaddr = obj->loadaddr; |
268 | ADFS_I(inode)->execaddr = obj->execaddr; |
269 | ADFS_I(inode)->attr = obj->attr; |
270 | |
271 | inode->i_mode = adfs_atts2mode(sb, inode); |
272 | adfs_adfs2unix_time(tv: &ts, inode); |
273 | inode_set_atime_to_ts(inode, ts); |
274 | inode_set_mtime_to_ts(inode, ts); |
275 | inode_set_ctime_to_ts(inode, ts); |
276 | |
277 | if (S_ISDIR(inode->i_mode)) { |
278 | inode->i_op = &adfs_dir_inode_operations; |
279 | inode->i_fop = &adfs_dir_operations; |
280 | } else if (S_ISREG(inode->i_mode)) { |
281 | inode->i_op = &adfs_file_inode_operations; |
282 | inode->i_fop = &adfs_file_operations; |
283 | inode->i_mapping->a_ops = &adfs_aops; |
284 | ADFS_I(inode)->mmu_private = inode->i_size; |
285 | } |
286 | |
287 | inode_fake_hash(inode); |
288 | |
289 | out: |
290 | return inode; |
291 | } |
292 | |
293 | /* |
294 | * Validate and convert a changed access mode/time to their ADFS equivalents. |
295 | * adfs_write_inode will actually write the information back to the directory |
296 | * later. |
297 | */ |
298 | int |
299 | adfs_notify_change(struct mnt_idmap *idmap, struct dentry *dentry, |
300 | struct iattr *attr) |
301 | { |
302 | struct inode *inode = d_inode(dentry); |
303 | struct super_block *sb = inode->i_sb; |
304 | unsigned int ia_valid = attr->ia_valid; |
305 | int error; |
306 | |
307 | error = setattr_prepare(&nop_mnt_idmap, dentry, attr); |
308 | |
309 | /* |
310 | * we can't change the UID or GID of any file - |
311 | * we have a global UID/GID in the superblock |
312 | */ |
313 | if ((ia_valid & ATTR_UID && !uid_eq(left: attr->ia_uid, right: ADFS_SB(sb)->s_uid)) || |
314 | (ia_valid & ATTR_GID && !gid_eq(left: attr->ia_gid, right: ADFS_SB(sb)->s_gid))) |
315 | error = -EPERM; |
316 | |
317 | if (error) |
318 | goto out; |
319 | |
320 | /* XXX: this is missing some actual on-disk truncation.. */ |
321 | if (ia_valid & ATTR_SIZE) |
322 | truncate_setsize(inode, newsize: attr->ia_size); |
323 | |
324 | if (ia_valid & ATTR_MTIME && adfs_inode_is_stamped(inode)) { |
325 | adfs_unix2adfs_time(inode, ts: &attr->ia_mtime); |
326 | adfs_adfs2unix_time(tv: &attr->ia_mtime, inode); |
327 | inode_set_mtime_to_ts(inode, ts: attr->ia_mtime); |
328 | } |
329 | |
330 | /* |
331 | * FIXME: should we make these == to i_mtime since we don't |
332 | * have the ability to represent them in our filesystem? |
333 | */ |
334 | if (ia_valid & ATTR_ATIME) |
335 | inode_set_atime_to_ts(inode, ts: attr->ia_atime); |
336 | if (ia_valid & ATTR_CTIME) |
337 | inode_set_ctime_to_ts(inode, ts: attr->ia_ctime); |
338 | if (ia_valid & ATTR_MODE) { |
339 | ADFS_I(inode)->attr = adfs_mode2atts(sb, inode, ia_mode: attr->ia_mode); |
340 | inode->i_mode = adfs_atts2mode(sb, inode); |
341 | } |
342 | |
343 | /* |
344 | * FIXME: should we be marking this inode dirty even if |
345 | * we don't have any metadata to write back? |
346 | */ |
347 | if (ia_valid & (ATTR_SIZE | ATTR_MTIME | ATTR_MODE)) |
348 | mark_inode_dirty(inode); |
349 | out: |
350 | return error; |
351 | } |
352 | |
353 | /* |
354 | * write an existing inode back to the directory, and therefore the disk. |
355 | * The adfs-specific inode data has already been updated by |
356 | * adfs_notify_change() |
357 | */ |
358 | int adfs_write_inode(struct inode *inode, struct writeback_control *wbc) |
359 | { |
360 | struct super_block *sb = inode->i_sb; |
361 | struct object_info obj; |
362 | |
363 | obj.indaddr = ADFS_I(inode)->indaddr; |
364 | obj.name_len = 0; |
365 | obj.parent_id = ADFS_I(inode)->parent_id; |
366 | obj.loadaddr = ADFS_I(inode)->loadaddr; |
367 | obj.execaddr = ADFS_I(inode)->execaddr; |
368 | obj.attr = ADFS_I(inode)->attr; |
369 | obj.size = inode->i_size; |
370 | |
371 | return adfs_dir_update(sb, obj: &obj, wait: wbc->sync_mode == WB_SYNC_ALL); |
372 | } |
373 | |