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 void adfs_write_failed(struct address_space *mapping, loff_t to)
50 struct inode *inode = mapping->host;
52 if (to > inode->i_size)
53 truncate_pagecache(inode, inode->i_size);
56 static 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)
63 ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
65 &ADFS_I(mapping->host)->mmu_private);
67 adfs_write_failed(mapping, pos + len);
72 static sector_t _adfs_bmap(struct address_space *mapping, sector_t block)
74 return generic_block_bmap(mapping, block, adfs_get_block);
77 static const struct address_space_operations adfs_aops = {
78 .readpage = adfs_readpage,
79 .writepage = adfs_writepage,
80 .write_begin = adfs_write_begin,
81 .write_end = generic_write_end,
86 * Convert ADFS attributes and filetype to Linux permission.
89 adfs_atts2mode(struct super_block *sb, struct inode *inode)
91 unsigned int attr = ADFS_I(inode)->attr;
93 struct adfs_sb_info *asb = ADFS_SB(sb);
95 if (attr & ADFS_NDA_DIRECTORY) {
96 mode = S_IRUGO & asb->s_owner_mask;
97 return S_IFDIR | S_IXUGO | mode;
100 switch (ADFS_I(inode)->filetype) {
101 case 0xfc0: /* LinkFS */
102 return S_IFLNK|S_IRWXUGO;
104 case 0xfe6: /* UnixExec */
105 rmask = S_IRUGO | S_IXUGO;
114 if (attr & ADFS_NDA_OWNER_READ)
115 mode |= rmask & asb->s_owner_mask;
117 if (attr & ADFS_NDA_OWNER_WRITE)
118 mode |= S_IWUGO & asb->s_owner_mask;
120 if (attr & ADFS_NDA_PUBLIC_READ)
121 mode |= rmask & asb->s_other_mask;
123 if (attr & ADFS_NDA_PUBLIC_WRITE)
124 mode |= S_IWUGO & asb->s_other_mask;
129 * Convert Linux permission to ADFS attribute. We try to do the reverse
130 * of atts2mode, but there is not a 1:1 translation.
133 adfs_mode2atts(struct super_block *sb, struct inode *inode)
137 struct adfs_sb_info *asb = ADFS_SB(sb);
139 /* FIXME: should we be able to alter a link? */
140 if (S_ISLNK(inode->i_mode))
141 return ADFS_I(inode)->attr;
143 if (S_ISDIR(inode->i_mode))
144 attr = ADFS_NDA_DIRECTORY;
148 mode = inode->i_mode & asb->s_owner_mask;
150 attr |= ADFS_NDA_OWNER_READ;
152 attr |= ADFS_NDA_OWNER_WRITE;
154 mode = inode->i_mode & asb->s_other_mask;
155 mode &= ~asb->s_owner_mask;
157 attr |= ADFS_NDA_PUBLIC_READ;
159 attr |= ADFS_NDA_PUBLIC_WRITE;
165 * Convert an ADFS time to Unix time. ADFS has a 40-bit centi-second time
166 * 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.
170 adfs_adfs2unix_time(struct timespec64 *tv, struct inode *inode)
172 unsigned int high, low;
173 /* 01 Jan 1970 00:00:00 (Unix epoch) as nanoseconds since
174 * 01 Jan 1900 00:00:00 (RISC OS epoch)
176 static const s64 nsec_unix_epoch_diff_risc_os_epoch =
177 2208988800000000000LL;
180 if (ADFS_I(inode)->stamped == 0)
183 high = ADFS_I(inode)->loadaddr & 0xFF; /* top 8 bits of timestamp */
184 low = ADFS_I(inode)->execaddr; /* bottom 32 bits of timestamp */
186 /* convert 40-bit centi-seconds to 32-bit seconds
187 * going via nanoseconds to retain precision
189 nsec = (((s64) high << 32) | (s64) low) * 10000000; /* cs to ns */
191 /* Files dated pre 01 Jan 1970 00:00:00. */
192 if (nsec < nsec_unix_epoch_diff_risc_os_epoch)
195 /* convert from RISC OS to Unix epoch */
196 nsec -= nsec_unix_epoch_diff_risc_os_epoch;
198 *tv = ns_to_timespec64(nsec);
202 *tv = current_time(inode);
206 tv->tv_sec = tv->tv_nsec = 0;
211 * Convert an Unix time to ADFS time. We only do this if the entry has a
212 * time/date stamp already.
215 adfs_unix2adfs_time(struct inode *inode, unsigned int secs)
217 unsigned int high, low;
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;
224 ADFS_I(inode)->loadaddr = (high >> 24) |
225 (ADFS_I(inode)->loadaddr & ~0xff);
226 ADFS_I(inode)->execaddr = (low & 255) | (high << 8);
231 * Fill in the inode information from the object information.
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.
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).
243 adfs_iget(struct super_block *sb, struct object_info *obj)
247 inode = new_inode(sb);
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;
256 inode->i_blocks = (inode->i_size + sb->s_blocksize - 1) >>
257 sb->s_blocksize_bits;
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.
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;
269 ADFS_I(inode)->filetype = obj->filetype;
270 ADFS_I(inode)->stamped = ((obj->loadaddr & 0xfff00000) == 0xfff00000);
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;
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;
287 inode_fake_hash(inode);
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
299 adfs_notify_change(struct dentry *dentry, struct iattr *attr)
301 struct inode *inode = d_inode(dentry);
302 struct super_block *sb = inode->i_sb;
303 unsigned int ia_valid = attr->ia_valid;
306 error = setattr_prepare(dentry, attr);
309 * we can't change the UID or GID of any file -
310 * we have a global UID/GID in the superblock
312 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)))
319 /* XXX: this is missing some actual on-disk truncation.. */
320 if (ia_valid & ATTR_SIZE)
321 truncate_setsize(inode, attr->ia_size);
323 if (ia_valid & ATTR_MTIME) {
324 inode->i_mtime = attr->ia_mtime;
325 adfs_unix2adfs_time(inode, attr->ia_mtime.tv_sec);
328 * FIXME: should we make these == to i_mtime since we don't
329 * have the ability to represent them in our filesystem?
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);
341 * FIXME: should we be marking this inode dirty even if
342 * we don't have any metadata to write back?
344 if (ia_valid & (ATTR_SIZE | ATTR_MTIME | ATTR_MODE))
345 mark_inode_dirty(inode);
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()
355 int adfs_write_inode(struct inode *inode, struct writeback_control *wbc)
357 struct super_block *sb = inode->i_sb;
358 struct object_info obj;
361 obj.file_id = inode->i_ino;
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;
369 ret = adfs_dir_update(sb, &obj, wbc->sync_mode == WB_SYNC_ALL);