2 * linux/fs/adfs/inode.c
4 * Copyright (C) 1997-1999 Russell King
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.
10 #include <linux/buffer_head.h>
11 #include <linux/writeback.h>
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.
19 adfs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh,
23 if (block >= inode->i_blocks)
26 block = __adfs_block_map(inode->i_sb, inode->i_ino, block);
28 map_bh(bh, inode->i_sb, block);
31 /* don't support allocation of blocks yet */
38 static int adfs_writepage(struct page *page, struct writeback_control *wbc)
40 return block_write_full_page(page, adfs_get_block, wbc);
43 static int adfs_readpage(struct file *file, struct page *page)
45 return block_read_full_page(page, adfs_get_block);
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)
55 ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
57 &ADFS_I(mapping->host)->mmu_private);
59 loff_t isize = mapping->host->i_size;
60 if (pos + len > isize)
61 vmtruncate(mapping->host, isize);
67 static sector_t _adfs_bmap(struct address_space *mapping, sector_t block)
69 return generic_block_bmap(mapping, block, adfs_get_block);
72 static const struct address_space_operations adfs_aops = {
73 .readpage = adfs_readpage,
74 .writepage = adfs_writepage,
75 .sync_page = block_sync_page,
76 .write_begin = adfs_write_begin,
77 .write_end = generic_write_end,
82 * Convert ADFS attributes and filetype to Linux permission.
85 adfs_atts2mode(struct super_block *sb, struct inode *inode)
87 unsigned int attr = ADFS_I(inode)->attr;
89 struct adfs_sb_info *asb = ADFS_SB(sb);
91 if (attr & ADFS_NDA_DIRECTORY) {
92 mode = S_IRUGO & asb->s_owner_mask;
93 return S_IFDIR | S_IXUGO | mode;
96 switch (ADFS_I(inode)->filetype) {
97 case 0xfc0: /* LinkFS */
98 return S_IFLNK|S_IRWXUGO;
100 case 0xfe6: /* UnixExec */
101 rmask = S_IRUGO | S_IXUGO;
110 if (attr & ADFS_NDA_OWNER_READ)
111 mode |= rmask & asb->s_owner_mask;
113 if (attr & ADFS_NDA_OWNER_WRITE)
114 mode |= S_IWUGO & asb->s_owner_mask;
116 if (attr & ADFS_NDA_PUBLIC_READ)
117 mode |= rmask & asb->s_other_mask;
119 if (attr & ADFS_NDA_PUBLIC_WRITE)
120 mode |= S_IWUGO & asb->s_other_mask;
125 * Convert Linux permission to ADFS attribute. We try to do the reverse
126 * of atts2mode, but there is not a 1:1 translation.
129 adfs_mode2atts(struct super_block *sb, struct inode *inode)
133 struct adfs_sb_info *asb = ADFS_SB(sb);
135 /* FIXME: should we be able to alter a link? */
136 if (S_ISLNK(inode->i_mode))
137 return ADFS_I(inode)->attr;
139 if (S_ISDIR(inode->i_mode))
140 attr = ADFS_NDA_DIRECTORY;
144 mode = inode->i_mode & asb->s_owner_mask;
146 attr |= ADFS_NDA_OWNER_READ;
148 attr |= ADFS_NDA_OWNER_WRITE;
150 mode = inode->i_mode & asb->s_other_mask;
151 mode &= ~asb->s_owner_mask;
153 attr |= ADFS_NDA_PUBLIC_READ;
155 attr |= ADFS_NDA_PUBLIC_WRITE;
161 * Convert an ADFS time to Unix time. ADFS has a 40-bit centi-second time
162 * referenced to 1 Jan 1900 (til 2248) so we need to discard 2208988800 seconds
163 * of time to convert from RISC OS epoch to Unix epoch.
166 adfs_adfs2unix_time(struct timespec *tv, struct inode *inode)
168 unsigned int high, low;
169 /* 01 Jan 1970 00:00:00 (Unix epoch) as nanoseconds since
170 * 01 Jan 1900 00:00:00 (RISC OS epoch)
172 static const s64 nsec_unix_epoch_diff_risc_os_epoch =
173 2208988800000000000LL;
176 if (ADFS_I(inode)->stamped == 0)
179 high = ADFS_I(inode)->loadaddr & 0xFF; /* top 8 bits of timestamp */
180 low = ADFS_I(inode)->execaddr; /* bottom 32 bits of timestamp */
182 /* convert 40-bit centi-seconds to 32-bit seconds
183 * going via nanoseconds to retain precision
185 nsec = (((s64) high << 32) | (s64) low) * 10000000; /* cs to ns */
187 /* Files dated pre 01 Jan 1970 00:00:00. */
188 if (nsec < nsec_unix_epoch_diff_risc_os_epoch)
191 /* convert from RISC OS to Unix epoch */
192 nsec -= nsec_unix_epoch_diff_risc_os_epoch;
194 *tv = ns_to_timespec(nsec);
202 tv->tv_sec = tv->tv_nsec = 0;
207 * Convert an Unix time to ADFS time. We only do this if the entry has a
208 * time/date stamp already.
211 adfs_unix2adfs_time(struct inode *inode, unsigned int secs)
213 unsigned int high, low;
215 if (ADFS_I(inode)->stamped) {
216 /* convert 32-bit seconds to 40-bit centi-seconds */
217 low = (secs & 255) * 100;
218 high = (secs / 256) * 100 + (low >> 8) + 0x336e996a;
220 ADFS_I(inode)->loadaddr = (high >> 24) |
221 (ADFS_I(inode)->loadaddr & ~0xff);
222 ADFS_I(inode)->execaddr = (low & 255) | (high << 8);
227 * Fill in the inode information from the object information.
229 * Note that this is an inode-less filesystem, so we can't use the inode
230 * number to reference the metadata on the media. Instead, we use the
231 * inode number to hold the object ID, which in turn will tell us where
232 * the data is held. We also save the parent object ID, and with these
233 * two, we can locate the metadata.
235 * This does mean that we rely on an objects parent remaining the same at
236 * all times - we cannot cope with a cross-directory rename (yet).
239 adfs_iget(struct super_block *sb, struct object_info *obj)
243 inode = new_inode(sb);
247 inode->i_uid = ADFS_SB(sb)->s_uid;
248 inode->i_gid = ADFS_SB(sb)->s_gid;
249 inode->i_ino = obj->file_id;
250 inode->i_size = obj->size;
252 inode->i_blocks = (inode->i_size + sb->s_blocksize - 1) >>
253 sb->s_blocksize_bits;
256 * we need to save the parent directory ID so that
257 * write_inode can update the directory information
258 * for this file. This will need special handling
259 * for cross-directory renames.
261 ADFS_I(inode)->parent_id = obj->parent_id;
262 ADFS_I(inode)->loadaddr = obj->loadaddr;
263 ADFS_I(inode)->execaddr = obj->execaddr;
264 ADFS_I(inode)->attr = obj->attr;
265 ADFS_I(inode)->filetype = obj->filetype;
266 ADFS_I(inode)->stamped = ((obj->loadaddr & 0xfff00000) == 0xfff00000);
268 inode->i_mode = adfs_atts2mode(sb, inode);
269 adfs_adfs2unix_time(&inode->i_mtime, inode);
270 inode->i_atime = inode->i_mtime;
271 inode->i_ctime = inode->i_mtime;
273 if (S_ISDIR(inode->i_mode)) {
274 inode->i_op = &adfs_dir_inode_operations;
275 inode->i_fop = &adfs_dir_operations;
276 } else if (S_ISREG(inode->i_mode)) {
277 inode->i_op = &adfs_file_inode_operations;
278 inode->i_fop = &adfs_file_operations;
279 inode->i_mapping->a_ops = &adfs_aops;
280 ADFS_I(inode)->mmu_private = inode->i_size;
283 insert_inode_hash(inode);
290 * Validate and convert a changed access mode/time to their ADFS equivalents.
291 * adfs_write_inode will actually write the information back to the directory
295 adfs_notify_change(struct dentry *dentry, struct iattr *attr)
297 struct inode *inode = dentry->d_inode;
298 struct super_block *sb = inode->i_sb;
299 unsigned int ia_valid = attr->ia_valid;
302 error = inode_change_ok(inode, attr);
305 * we can't change the UID or GID of any file -
306 * we have a global UID/GID in the superblock
308 if ((ia_valid & ATTR_UID && attr->ia_uid != ADFS_SB(sb)->s_uid) ||
309 (ia_valid & ATTR_GID && attr->ia_gid != ADFS_SB(sb)->s_gid))
315 /* XXX: this is missing some actual on-disk truncation.. */
316 if (ia_valid & ATTR_SIZE)
317 truncate_setsize(inode, attr->ia_size);
319 if (ia_valid & ATTR_MTIME) {
320 inode->i_mtime = attr->ia_mtime;
321 adfs_unix2adfs_time(inode, attr->ia_mtime.tv_sec);
324 * FIXME: should we make these == to i_mtime since we don't
325 * have the ability to represent them in our filesystem?
327 if (ia_valid & ATTR_ATIME)
328 inode->i_atime = attr->ia_atime;
329 if (ia_valid & ATTR_CTIME)
330 inode->i_ctime = attr->ia_ctime;
331 if (ia_valid & ATTR_MODE) {
332 ADFS_I(inode)->attr = adfs_mode2atts(sb, inode);
333 inode->i_mode = adfs_atts2mode(sb, inode);
337 * FIXME: should we be marking this inode dirty even if
338 * we don't have any metadata to write back?
340 if (ia_valid & (ATTR_SIZE | ATTR_MTIME | ATTR_MODE))
341 mark_inode_dirty(inode);
347 * write an existing inode back to the directory, and therefore the disk.
348 * The adfs-specific inode data has already been updated by
349 * adfs_notify_change()
351 int adfs_write_inode(struct inode *inode, struct writeback_control *wbc)
353 struct super_block *sb = inode->i_sb;
354 struct object_info obj;
357 obj.file_id = inode->i_ino;
359 obj.parent_id = ADFS_I(inode)->parent_id;
360 obj.loadaddr = ADFS_I(inode)->loadaddr;
361 obj.execaddr = ADFS_I(inode)->execaddr;
362 obj.attr = ADFS_I(inode)->attr;
363 obj.size = inode->i_size;
365 ret = adfs_dir_update(sb, &obj, wbc->sync_mode == WB_SYNC_ALL);