1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/fs/adfs/inode.c
5 * Copyright (C) 1997-1999 Russell King
7 #include <linux/buffer_head.h>
8 #include <linux/writeback.h>
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.
16 adfs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh,
20 if (block >= inode->i_blocks)
23 block = __adfs_block_map(inode->i_sb, ADFS_I(inode)->indaddr,
26 map_bh(bh, inode->i_sb, block);
29 /* don't support allocation of blocks yet */
36 static int adfs_writepage(struct page *page, struct writeback_control *wbc)
38 return block_write_full_page(page, adfs_get_block, wbc);
41 static int adfs_readpage(struct file *file, struct page *page)
43 return block_read_full_page(page, adfs_get_block);
46 static void adfs_write_failed(struct address_space *mapping, loff_t to)
48 struct inode *inode = mapping->host;
50 if (to > inode->i_size)
51 truncate_pagecache(inode, inode->i_size);
54 static int adfs_write_begin(struct file *file, struct address_space *mapping,
55 loff_t pos, unsigned len, unsigned flags,
56 struct page **pagep, void **fsdata)
61 ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
63 &ADFS_I(mapping->host)->mmu_private);
65 adfs_write_failed(mapping, pos + len);
70 static sector_t _adfs_bmap(struct address_space *mapping, sector_t block)
72 return generic_block_bmap(mapping, block, adfs_get_block);
75 static const struct address_space_operations adfs_aops = {
76 .set_page_dirty = __set_page_dirty_buffers,
77 .readpage = adfs_readpage,
78 .writepage = adfs_writepage,
79 .write_begin = adfs_write_begin,
80 .write_end = generic_write_end,
85 * Convert ADFS attributes and filetype to Linux permission.
88 adfs_atts2mode(struct super_block *sb, struct inode *inode)
90 unsigned int attr = ADFS_I(inode)->attr;
92 struct adfs_sb_info *asb = ADFS_SB(sb);
94 if (attr & ADFS_NDA_DIRECTORY) {
95 mode = S_IRUGO & asb->s_owner_mask;
96 return S_IFDIR | S_IXUGO | mode;
99 switch (adfs_filetype(ADFS_I(inode)->loadaddr)) {
100 case 0xfc0: /* LinkFS */
101 return S_IFLNK|S_IRWXUGO;
103 case 0xfe6: /* UnixExec */
104 rmask = S_IRUGO | S_IXUGO;
113 if (attr & ADFS_NDA_OWNER_READ)
114 mode |= rmask & asb->s_owner_mask;
116 if (attr & ADFS_NDA_OWNER_WRITE)
117 mode |= S_IWUGO & asb->s_owner_mask;
119 if (attr & ADFS_NDA_PUBLIC_READ)
120 mode |= rmask & asb->s_other_mask;
122 if (attr & ADFS_NDA_PUBLIC_WRITE)
123 mode |= S_IWUGO & asb->s_other_mask;
128 * Convert Linux permission to ADFS attribute. We try to do the reverse
129 * of atts2mode, but there is not a 1:1 translation.
131 static int adfs_mode2atts(struct super_block *sb, struct inode *inode,
134 struct adfs_sb_info *asb = ADFS_SB(sb);
138 /* FIXME: should we be able to alter a link? */
139 if (S_ISLNK(inode->i_mode))
140 return ADFS_I(inode)->attr;
142 /* Directories do not have read/write permissions on the media */
143 if (S_ISDIR(inode->i_mode))
144 return ADFS_NDA_DIRECTORY;
147 mode = ia_mode & asb->s_owner_mask;
149 attr |= ADFS_NDA_OWNER_READ;
151 attr |= ADFS_NDA_OWNER_WRITE;
153 mode = ia_mode & asb->s_other_mask;
154 mode &= ~asb->s_owner_mask;
156 attr |= ADFS_NDA_PUBLIC_READ;
158 attr |= ADFS_NDA_PUBLIC_WRITE;
163 static const s64 nsec_unix_epoch_diff_risc_os_epoch = 2208988800000000000LL;
166 * Convert an ADFS time to Unix time. ADFS has a 40-bit centi-second time
167 * referenced to 1 Jan 1900 (til 2248) so we need to discard 2208988800 seconds
168 * of time to convert from RISC OS epoch to Unix epoch.
171 adfs_adfs2unix_time(struct timespec64 *tv, struct inode *inode)
173 unsigned int high, low;
174 /* 01 Jan 1970 00:00:00 (Unix epoch) as nanoseconds since
175 * 01 Jan 1900 00:00:00 (RISC OS epoch)
179 if (!adfs_inode_is_stamped(inode))
182 high = ADFS_I(inode)->loadaddr & 0xFF; /* top 8 bits of timestamp */
183 low = ADFS_I(inode)->execaddr; /* bottom 32 bits of timestamp */
185 /* convert 40-bit centi-seconds to 32-bit seconds
186 * going via nanoseconds to retain precision
188 nsec = (((s64) high << 32) | (s64) low) * 10000000; /* cs to ns */
190 /* Files dated pre 01 Jan 1970 00:00:00. */
191 if (nsec < nsec_unix_epoch_diff_risc_os_epoch)
194 /* convert from RISC OS to Unix epoch */
195 nsec -= nsec_unix_epoch_diff_risc_os_epoch;
197 *tv = ns_to_timespec64(nsec);
201 *tv = current_time(inode);
205 tv->tv_sec = tv->tv_nsec = 0;
209 /* Convert an Unix time to ADFS time for an entry that is already stamped. */
210 static void adfs_unix2adfs_time(struct inode *inode,
211 const struct timespec64 *ts)
213 s64 cs, nsec = timespec64_to_ns(ts);
215 /* convert from Unix to RISC OS epoch */
216 nsec += nsec_unix_epoch_diff_risc_os_epoch;
218 /* convert from nanoseconds to centiseconds */
219 cs = div_s64(nsec, 10000000);
221 cs = clamp_t(s64, cs, 0, 0xffffffffff);
223 ADFS_I(inode)->loadaddr &= ~0xff;
224 ADFS_I(inode)->loadaddr |= (cs >> 32) & 0xff;
225 ADFS_I(inode)->execaddr = cs;
229 * Fill in the inode information from the object information.
231 * Note that this is an inode-less filesystem, so we can't use the inode
232 * number to reference the metadata on the media. Instead, we use the
233 * inode number to hold the object ID, which in turn will tell us where
234 * the data is held. We also save the parent object ID, and with these
235 * two, we can locate the metadata.
237 * This does mean that we rely on an objects parent remaining the same at
238 * all times - we cannot cope with a cross-directory rename (yet).
241 adfs_iget(struct super_block *sb, struct object_info *obj)
245 inode = new_inode(sb);
249 inode->i_uid = ADFS_SB(sb)->s_uid;
250 inode->i_gid = ADFS_SB(sb)->s_gid;
251 inode->i_ino = obj->indaddr;
252 inode->i_size = obj->size;
254 inode->i_blocks = (inode->i_size + sb->s_blocksize - 1) >>
255 sb->s_blocksize_bits;
258 * we need to save the parent directory ID so that
259 * write_inode can update the directory information
260 * for this file. This will need special handling
261 * for cross-directory renames.
263 ADFS_I(inode)->parent_id = obj->parent_id;
264 ADFS_I(inode)->indaddr = obj->indaddr;
265 ADFS_I(inode)->loadaddr = obj->loadaddr;
266 ADFS_I(inode)->execaddr = obj->execaddr;
267 ADFS_I(inode)->attr = obj->attr;
269 inode->i_mode = adfs_atts2mode(sb, inode);
270 adfs_adfs2unix_time(&inode->i_mtime, inode);
271 inode->i_atime = inode->i_mtime;
272 inode->i_ctime = inode->i_mtime;
274 if (S_ISDIR(inode->i_mode)) {
275 inode->i_op = &adfs_dir_inode_operations;
276 inode->i_fop = &adfs_dir_operations;
277 } else if (S_ISREG(inode->i_mode)) {
278 inode->i_op = &adfs_file_inode_operations;
279 inode->i_fop = &adfs_file_operations;
280 inode->i_mapping->a_ops = &adfs_aops;
281 ADFS_I(inode)->mmu_private = inode->i_size;
284 inode_fake_hash(inode);
291 * Validate and convert a changed access mode/time to their ADFS equivalents.
292 * adfs_write_inode will actually write the information back to the directory
296 adfs_notify_change(struct user_namespace *mnt_userns, struct dentry *dentry,
299 struct inode *inode = d_inode(dentry);
300 struct super_block *sb = inode->i_sb;
301 unsigned int ia_valid = attr->ia_valid;
304 error = setattr_prepare(&init_user_ns, dentry, attr);
307 * we can't change the UID or GID of any file -
308 * we have a global UID/GID in the superblock
310 if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, ADFS_SB(sb)->s_uid)) ||
311 (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, ADFS_SB(sb)->s_gid)))
317 /* XXX: this is missing some actual on-disk truncation.. */
318 if (ia_valid & ATTR_SIZE)
319 truncate_setsize(inode, attr->ia_size);
321 if (ia_valid & ATTR_MTIME && adfs_inode_is_stamped(inode)) {
322 adfs_unix2adfs_time(inode, &attr->ia_mtime);
323 adfs_adfs2unix_time(&inode->i_mtime, inode);
327 * FIXME: should we make these == to i_mtime since we don't
328 * have the ability to represent them in our filesystem?
330 if (ia_valid & ATTR_ATIME)
331 inode->i_atime = attr->ia_atime;
332 if (ia_valid & ATTR_CTIME)
333 inode->i_ctime = attr->ia_ctime;
334 if (ia_valid & ATTR_MODE) {
335 ADFS_I(inode)->attr = adfs_mode2atts(sb, inode, attr->ia_mode);
336 inode->i_mode = adfs_atts2mode(sb, inode);
340 * FIXME: should we be marking this inode dirty even if
341 * we don't have any metadata to write back?
343 if (ia_valid & (ATTR_SIZE | ATTR_MTIME | ATTR_MODE))
344 mark_inode_dirty(inode);
350 * write an existing inode back to the directory, and therefore the disk.
351 * The adfs-specific inode data has already been updated by
352 * adfs_notify_change()
354 int adfs_write_inode(struct inode *inode, struct writeback_control *wbc)
356 struct super_block *sb = inode->i_sb;
357 struct object_info obj;
359 obj.indaddr = ADFS_I(inode)->indaddr;
361 obj.parent_id = ADFS_I(inode)->parent_id;
362 obj.loadaddr = ADFS_I(inode)->loadaddr;
363 obj.execaddr = ADFS_I(inode)->execaddr;
364 obj.attr = ADFS_I(inode)->attr;
365 obj.size = inode->i_size;
367 return adfs_dir_update(sb, &obj, wbc->sync_mode == WB_SYNC_ALL);