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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070010#include <linux/buffer_head.h>
Christoph Hellwiga9185b42010-03-05 09:21:37 +010011#include <linux/writeback.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#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 */
18static int
19adfs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh,
20 int create)
21{
Linus Torvalds1da177e2005-04-16 15:20:36 -070022 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070034abort_toobig:
35 return 0;
36}
37
38static int adfs_writepage(struct page *page, struct writeback_control *wbc)
39{
40 return block_write_full_page(page, adfs_get_block, wbc);
41}
42
43static int adfs_readpage(struct file *file, struct page *page)
44{
45 return block_read_full_page(page, adfs_get_block);
46}
47
Marco Stornelli62295182012-12-15 11:51:11 +010048static void adfs_write_failed(struct address_space *mapping, loff_t to)
49{
50 struct inode *inode = mapping->host;
51
52 if (to > inode->i_size)
53 truncate_pagecache(inode, to, inode->i_size);
54}
55
Nick Pigginb4585722007-10-16 01:25:23 -070056static int adfs_write_begin(struct file *file, struct address_space *mapping,
57 loff_t pos, unsigned len, unsigned flags,
58 struct page **pagep, void **fsdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -070059{
Christoph Hellwig282dc172010-06-04 11:29:55 +020060 int ret;
61
Nick Pigginb4585722007-10-16 01:25:23 -070062 *pagep = NULL;
Christoph Hellwig282dc172010-06-04 11:29:55 +020063 ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
Nick Pigginb4585722007-10-16 01:25:23 -070064 adfs_get_block,
65 &ADFS_I(mapping->host)->mmu_private);
Marco Stornelli62295182012-12-15 11:51:11 +010066 if (unlikely(ret))
67 adfs_write_failed(mapping, pos + len);
Christoph Hellwig282dc172010-06-04 11:29:55 +020068
69 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -070070}
71
72static sector_t _adfs_bmap(struct address_space *mapping, sector_t block)
73{
74 return generic_block_bmap(mapping, block, adfs_get_block);
75}
76
Christoph Hellwigf5e54d62006-06-28 04:26:44 -070077static const struct address_space_operations adfs_aops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 .readpage = adfs_readpage,
79 .writepage = adfs_writepage,
Nick Pigginb4585722007-10-16 01:25:23 -070080 .write_begin = adfs_write_begin,
81 .write_end = generic_write_end,
Linus Torvalds1da177e2005-04-16 15:20:36 -070082 .bmap = _adfs_bmap
83};
84
Linus Torvalds1da177e2005-04-16 15:20:36 -070085/*
86 * Convert ADFS attributes and filetype to Linux permission.
87 */
88static umode_t
89adfs_atts2mode(struct super_block *sb, struct inode *inode)
90{
Stuart Swalesda23ef02011-03-22 16:35:06 -070091 unsigned int attr = ADFS_I(inode)->attr;
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 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
Stuart Swalesda23ef02011-03-22 16:35:06 -0700100 switch (ADFS_I(inode)->filetype) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 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 */
132static int
133adfs_mode2atts(struct super_block *sb, struct inode *inode)
134{
135 umode_t mode;
136 int attr;
137 struct adfs_sb_info *asb = ADFS_SB(sb);
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 if (S_ISDIR(inode->i_mode))
144 attr = ADFS_NDA_DIRECTORY;
145 else
146 attr = 0;
147
148 mode = inode->i_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 = inode->i_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/*
165 * Convert an ADFS time to Unix time. ADFS has a 40-bit centi-second time
Stuart Swales7a9730a2011-03-22 16:35:05 -0700166 * referenced to 1 Jan 1900 (til 2248) so we need to discard 2208988800 seconds
167 * of time to convert from RISC OS epoch to Unix epoch.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 */
169static void
170adfs_adfs2unix_time(struct timespec *tv, struct inode *inode)
171{
172 unsigned int high, low;
Stuart Swales7a9730a2011-03-22 16:35:05 -0700173 /* 01 Jan 1970 00:00:00 (Unix epoch) as nanoseconds since
174 * 01 Jan 1900 00:00:00 (RISC OS epoch)
175 */
176 static const s64 nsec_unix_epoch_diff_risc_os_epoch =
177 2208988800000000000LL;
178 s64 nsec;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179
180 if (ADFS_I(inode)->stamped == 0)
181 goto cur_time;
182
Stuart Swales7a9730a2011-03-22 16:35:05 -0700183 high = ADFS_I(inode)->loadaddr & 0xFF; /* top 8 bits of timestamp */
184 low = ADFS_I(inode)->execaddr; /* bottom 32 bits of timestamp */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185
Stuart Swales7a9730a2011-03-22 16:35:05 -0700186 /* 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 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190
191 /* Files dated pre 01 Jan 1970 00:00:00. */
Stuart Swales7a9730a2011-03-22 16:35:05 -0700192 if (nsec < nsec_unix_epoch_diff_risc_os_epoch)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 goto too_early;
194
Stuart Swales7a9730a2011-03-22 16:35:05 -0700195 /* convert from RISC OS to Unix epoch */
196 nsec -= nsec_unix_epoch_diff_risc_os_epoch;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197
Stuart Swales7a9730a2011-03-22 16:35:05 -0700198 *tv = ns_to_timespec(nsec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 return;
200
201 cur_time:
Stuart Swales7a9730a2011-03-22 16:35:05 -0700202 *tv = CURRENT_TIME;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 return;
204
205 too_early:
206 tv->tv_sec = tv->tv_nsec = 0;
207 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208}
209
210/*
211 * Convert an Unix time to ADFS time. We only do this if the entry has a
212 * time/date stamp already.
213 */
214static void
215adfs_unix2adfs_time(struct inode *inode, unsigned int secs)
216{
217 unsigned int high, low;
218
219 if (ADFS_I(inode)->stamped) {
220 /* convert 32-bit seconds to 40-bit centi-seconds */
221 low = (secs & 255) * 100;
222 high = (secs / 256) * 100 + (low >> 8) + 0x336e996a;
223
224 ADFS_I(inode)->loadaddr = (high >> 24) |
225 (ADFS_I(inode)->loadaddr & ~0xff);
226 ADFS_I(inode)->execaddr = (low & 255) | (high << 8);
227 }
228}
229
230/*
231 * Fill in the inode information from the object information.
232 *
233 * Note that this is an inode-less filesystem, so we can't use the inode
234 * number to reference the metadata on the media. Instead, we use the
235 * inode number to hold the object ID, which in turn will tell us where
236 * the data is held. We also save the parent object ID, and with these
237 * two, we can locate the metadata.
238 *
239 * This does mean that we rely on an objects parent remaining the same at
240 * all times - we cannot cope with a cross-directory rename (yet).
241 */
242struct inode *
243adfs_iget(struct super_block *sb, struct object_info *obj)
244{
245 struct inode *inode;
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->file_id;
254 inode->i_size = obj->size;
Miklos Szeredibfe86842011-10-28 14:13:29 +0200255 set_nlink(inode, 2);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 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)->loadaddr = obj->loadaddr;
267 ADFS_I(inode)->execaddr = obj->execaddr;
268 ADFS_I(inode)->attr = obj->attr;
Stuart Swalesda23ef02011-03-22 16:35:06 -0700269 ADFS_I(inode)->filetype = obj->filetype;
270 ADFS_I(inode)->stamped = ((obj->loadaddr & 0xfff00000) == 0xfff00000);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271
272 inode->i_mode = adfs_atts2mode(sb, inode);
273 adfs_adfs2unix_time(&inode->i_mtime, inode);
274 inode->i_atime = inode->i_mtime;
275 inode->i_ctime = inode->i_mtime;
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 insert_inode_hash(inode);
288
289out:
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 */
298int
299adfs_notify_change(struct dentry *dentry, struct iattr *attr)
300{
301 struct inode *inode = dentry->d_inode;
302 struct super_block *sb = inode->i_sb;
303 unsigned int ia_valid = attr->ia_valid;
304 int error;
305
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306 error = inode_change_ok(inode, attr);
307
308 /*
309 * we can't change the UID or GID of any file -
310 * we have a global UID/GID in the superblock
311 */
Eric W. Biedermanc010d1f2012-02-07 15:58:38 -0800312 if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, ADFS_SB(sb)->s_uid)) ||
313 (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, ADFS_SB(sb)->s_gid)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 error = -EPERM;
315
316 if (error)
317 goto out;
318
npiggin@suse.de15c6fd92010-05-27 01:05:34 +1000319 /* XXX: this is missing some actual on-disk truncation.. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 if (ia_valid & ATTR_SIZE)
Christoph Hellwig2c27c652010-06-04 11:30:04 +0200321 truncate_setsize(inode, attr->ia_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322
323 if (ia_valid & ATTR_MTIME) {
324 inode->i_mtime = attr->ia_mtime;
325 adfs_unix2adfs_time(inode, attr->ia_mtime.tv_sec);
326 }
327 /*
328 * FIXME: should we make these == to i_mtime since we don't
329 * have the ability to represent them in our filesystem?
330 */
331 if (ia_valid & ATTR_ATIME)
332 inode->i_atime = attr->ia_atime;
333 if (ia_valid & ATTR_CTIME)
334 inode->i_ctime = attr->ia_ctime;
335 if (ia_valid & ATTR_MODE) {
336 ADFS_I(inode)->attr = adfs_mode2atts(sb, inode);
337 inode->i_mode = adfs_atts2mode(sb, inode);
338 }
339
340 /*
341 * FIXME: should we be marking this inode dirty even if
342 * we don't have any metadata to write back?
343 */
344 if (ia_valid & (ATTR_SIZE | ATTR_MTIME | ATTR_MODE))
345 mark_inode_dirty(inode);
346out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 return error;
348}
349
350/*
351 * write an existing inode back to the directory, and therefore the disk.
352 * The adfs-specific inode data has already been updated by
353 * adfs_notify_change()
354 */
Christoph Hellwiga9185b42010-03-05 09:21:37 +0100355int adfs_write_inode(struct inode *inode, struct writeback_control *wbc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356{
357 struct super_block *sb = inode->i_sb;
358 struct object_info obj;
359 int ret;
360
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 obj.file_id = inode->i_ino;
362 obj.name_len = 0;
363 obj.parent_id = ADFS_I(inode)->parent_id;
364 obj.loadaddr = ADFS_I(inode)->loadaddr;
365 obj.execaddr = ADFS_I(inode)->execaddr;
366 obj.attr = ADFS_I(inode)->attr;
367 obj.size = inode->i_size;
368
Christoph Hellwiga9185b42010-03-05 09:21:37 +0100369 ret = adfs_dir_update(sb, &obj, wbc->sync_mode == WB_SYNC_ALL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 return ret;
371}