xref: /kernel/linux/linux-5.10/fs/affs/file.c (revision 8c2ecf20)
1// SPDX-License-Identifier: GPL-2.0
2/*
3 *  linux/fs/affs/file.c
4 *
5 *  (c) 1996  Hans-Joachim Widmaier - Rewritten
6 *
7 *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
8 *
9 *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
10 *
11 *  (C) 1991  Linus Torvalds - minix filesystem
12 *
13 *  affs regular file handling primitives
14 */
15
16#include <linux/uio.h>
17#include <linux/blkdev.h>
18#include "affs.h"
19
20static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
21
22static int
23affs_file_open(struct inode *inode, struct file *filp)
24{
25	pr_debug("open(%lu,%d)\n",
26		 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
27	atomic_inc(&AFFS_I(inode)->i_opencnt);
28	return 0;
29}
30
31static int
32affs_file_release(struct inode *inode, struct file *filp)
33{
34	pr_debug("release(%lu, %d)\n",
35		 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
36
37	if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
38		inode_lock(inode);
39		if (inode->i_size != AFFS_I(inode)->mmu_private)
40			affs_truncate(inode);
41		affs_free_prealloc(inode);
42		inode_unlock(inode);
43	}
44
45	return 0;
46}
47
48static int
49affs_grow_extcache(struct inode *inode, u32 lc_idx)
50{
51	struct super_block	*sb = inode->i_sb;
52	struct buffer_head	*bh;
53	u32 lc_max;
54	int i, j, key;
55
56	if (!AFFS_I(inode)->i_lc) {
57		char *ptr = (char *)get_zeroed_page(GFP_NOFS);
58		if (!ptr)
59			return -ENOMEM;
60		AFFS_I(inode)->i_lc = (u32 *)ptr;
61		AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
62	}
63
64	lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
65
66	if (AFFS_I(inode)->i_extcnt > lc_max) {
67		u32 lc_shift, lc_mask, tmp, off;
68
69		/* need to recalculate linear cache, start from old size */
70		lc_shift = AFFS_I(inode)->i_lc_shift;
71		tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
72		for (; tmp; tmp >>= 1)
73			lc_shift++;
74		lc_mask = (1 << lc_shift) - 1;
75
76		/* fix idx and old size to new shift */
77		lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
78		AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
79
80		/* first shrink old cache to make more space */
81		off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
82		for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
83			AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
84
85		AFFS_I(inode)->i_lc_shift = lc_shift;
86		AFFS_I(inode)->i_lc_mask = lc_mask;
87	}
88
89	/* fill cache to the needed index */
90	i = AFFS_I(inode)->i_lc_size;
91	AFFS_I(inode)->i_lc_size = lc_idx + 1;
92	for (; i <= lc_idx; i++) {
93		if (!i) {
94			AFFS_I(inode)->i_lc[0] = inode->i_ino;
95			continue;
96		}
97		key = AFFS_I(inode)->i_lc[i - 1];
98		j = AFFS_I(inode)->i_lc_mask + 1;
99		// unlock cache
100		for (; j > 0; j--) {
101			bh = affs_bread(sb, key);
102			if (!bh)
103				goto err;
104			key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
105			affs_brelse(bh);
106		}
107		// lock cache
108		AFFS_I(inode)->i_lc[i] = key;
109	}
110
111	return 0;
112
113err:
114	// lock cache
115	return -EIO;
116}
117
118static struct buffer_head *
119affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
120{
121	struct super_block *sb = inode->i_sb;
122	struct buffer_head *new_bh;
123	u32 blocknr, tmp;
124
125	blocknr = affs_alloc_block(inode, bh->b_blocknr);
126	if (!blocknr)
127		return ERR_PTR(-ENOSPC);
128
129	new_bh = affs_getzeroblk(sb, blocknr);
130	if (!new_bh) {
131		affs_free_block(sb, blocknr);
132		return ERR_PTR(-EIO);
133	}
134
135	AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
136	AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
137	AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
138	AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
139	affs_fix_checksum(sb, new_bh);
140
141	mark_buffer_dirty_inode(new_bh, inode);
142
143	tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
144	if (tmp)
145		affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
146	AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
147	affs_adjust_checksum(bh, blocknr - tmp);
148	mark_buffer_dirty_inode(bh, inode);
149
150	AFFS_I(inode)->i_extcnt++;
151	mark_inode_dirty(inode);
152
153	return new_bh;
154}
155
156static inline struct buffer_head *
157affs_get_extblock(struct inode *inode, u32 ext)
158{
159	/* inline the simplest case: same extended block as last time */
160	struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
161	if (ext == AFFS_I(inode)->i_ext_last)
162		get_bh(bh);
163	else
164		/* we have to do more (not inlined) */
165		bh = affs_get_extblock_slow(inode, ext);
166
167	return bh;
168}
169
170static struct buffer_head *
171affs_get_extblock_slow(struct inode *inode, u32 ext)
172{
173	struct super_block *sb = inode->i_sb;
174	struct buffer_head *bh;
175	u32 ext_key;
176	u32 lc_idx, lc_off, ac_idx;
177	u32 tmp, idx;
178
179	if (ext == AFFS_I(inode)->i_ext_last + 1) {
180		/* read the next extended block from the current one */
181		bh = AFFS_I(inode)->i_ext_bh;
182		ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
183		if (ext < AFFS_I(inode)->i_extcnt)
184			goto read_ext;
185		BUG_ON(ext > AFFS_I(inode)->i_extcnt);
186		bh = affs_alloc_extblock(inode, bh, ext);
187		if (IS_ERR(bh))
188			return bh;
189		goto store_ext;
190	}
191
192	if (ext == 0) {
193		/* we seek back to the file header block */
194		ext_key = inode->i_ino;
195		goto read_ext;
196	}
197
198	if (ext >= AFFS_I(inode)->i_extcnt) {
199		struct buffer_head *prev_bh;
200
201		/* allocate a new extended block */
202		BUG_ON(ext > AFFS_I(inode)->i_extcnt);
203
204		/* get previous extended block */
205		prev_bh = affs_get_extblock(inode, ext - 1);
206		if (IS_ERR(prev_bh))
207			return prev_bh;
208		bh = affs_alloc_extblock(inode, prev_bh, ext);
209		affs_brelse(prev_bh);
210		if (IS_ERR(bh))
211			return bh;
212		goto store_ext;
213	}
214
215again:
216	/* check if there is an extended cache and whether it's large enough */
217	lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
218	lc_off = ext & AFFS_I(inode)->i_lc_mask;
219
220	if (lc_idx >= AFFS_I(inode)->i_lc_size) {
221		int err;
222
223		err = affs_grow_extcache(inode, lc_idx);
224		if (err)
225			return ERR_PTR(err);
226		goto again;
227	}
228
229	/* every n'th key we find in the linear cache */
230	if (!lc_off) {
231		ext_key = AFFS_I(inode)->i_lc[lc_idx];
232		goto read_ext;
233	}
234
235	/* maybe it's still in the associative cache */
236	ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
237	if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
238		ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
239		goto read_ext;
240	}
241
242	/* try to find one of the previous extended blocks */
243	tmp = ext;
244	idx = ac_idx;
245	while (--tmp, --lc_off > 0) {
246		idx = (idx - 1) & AFFS_AC_MASK;
247		if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
248			ext_key = AFFS_I(inode)->i_ac[idx].key;
249			goto find_ext;
250		}
251	}
252
253	/* fall back to the linear cache */
254	ext_key = AFFS_I(inode)->i_lc[lc_idx];
255find_ext:
256	/* read all extended blocks until we find the one we need */
257	//unlock cache
258	do {
259		bh = affs_bread(sb, ext_key);
260		if (!bh)
261			goto err_bread;
262		ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
263		affs_brelse(bh);
264		tmp++;
265	} while (tmp < ext);
266	//lock cache
267
268	/* store it in the associative cache */
269	// recalculate ac_idx?
270	AFFS_I(inode)->i_ac[ac_idx].ext = ext;
271	AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
272
273read_ext:
274	/* finally read the right extended block */
275	//unlock cache
276	bh = affs_bread(sb, ext_key);
277	if (!bh)
278		goto err_bread;
279	//lock cache
280
281store_ext:
282	/* release old cached extended block and store the new one */
283	affs_brelse(AFFS_I(inode)->i_ext_bh);
284	AFFS_I(inode)->i_ext_last = ext;
285	AFFS_I(inode)->i_ext_bh = bh;
286	get_bh(bh);
287
288	return bh;
289
290err_bread:
291	affs_brelse(bh);
292	return ERR_PTR(-EIO);
293}
294
295static int
296affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
297{
298	struct super_block	*sb = inode->i_sb;
299	struct buffer_head	*ext_bh;
300	u32			 ext;
301
302	pr_debug("%s(%lu, %llu)\n", __func__, inode->i_ino,
303		 (unsigned long long)block);
304
305	BUG_ON(block > (sector_t)0x7fffffffUL);
306
307	if (block >= AFFS_I(inode)->i_blkcnt) {
308		if (block > AFFS_I(inode)->i_blkcnt || !create)
309			goto err_big;
310	} else
311		create = 0;
312
313	//lock cache
314	affs_lock_ext(inode);
315
316	ext = (u32)block / AFFS_SB(sb)->s_hashsize;
317	block -= ext * AFFS_SB(sb)->s_hashsize;
318	ext_bh = affs_get_extblock(inode, ext);
319	if (IS_ERR(ext_bh))
320		goto err_ext;
321	map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
322
323	if (create) {
324		u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
325		if (!blocknr)
326			goto err_alloc;
327		set_buffer_new(bh_result);
328		AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
329		AFFS_I(inode)->i_blkcnt++;
330
331		/* store new block */
332		if (bh_result->b_blocknr)
333			affs_warning(sb, "get_block",
334				     "block already set (%llx)",
335				     (unsigned long long)bh_result->b_blocknr);
336		AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
337		AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
338		affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
339		bh_result->b_blocknr = blocknr;
340
341		if (!block) {
342			/* insert first block into header block */
343			u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
344			if (tmp)
345				affs_warning(sb, "get_block", "first block already set (%d)", tmp);
346			AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
347			affs_adjust_checksum(ext_bh, blocknr - tmp);
348		}
349	}
350
351	affs_brelse(ext_bh);
352	//unlock cache
353	affs_unlock_ext(inode);
354	return 0;
355
356err_big:
357	affs_error(inode->i_sb, "get_block", "strange block request %llu",
358		   (unsigned long long)block);
359	return -EIO;
360err_ext:
361	// unlock cache
362	affs_unlock_ext(inode);
363	return PTR_ERR(ext_bh);
364err_alloc:
365	brelse(ext_bh);
366	clear_buffer_mapped(bh_result);
367	bh_result->b_bdev = NULL;
368	// unlock cache
369	affs_unlock_ext(inode);
370	return -ENOSPC;
371}
372
373static int affs_writepage(struct page *page, struct writeback_control *wbc)
374{
375	return block_write_full_page(page, affs_get_block, wbc);
376}
377
378static int affs_readpage(struct file *file, struct page *page)
379{
380	return block_read_full_page(page, affs_get_block);
381}
382
383static void affs_write_failed(struct address_space *mapping, loff_t to)
384{
385	struct inode *inode = mapping->host;
386
387	if (to > inode->i_size) {
388		truncate_pagecache(inode, inode->i_size);
389		affs_truncate(inode);
390	}
391}
392
393static ssize_t
394affs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
395{
396	struct file *file = iocb->ki_filp;
397	struct address_space *mapping = file->f_mapping;
398	struct inode *inode = mapping->host;
399	size_t count = iov_iter_count(iter);
400	loff_t offset = iocb->ki_pos;
401	ssize_t ret;
402
403	if (iov_iter_rw(iter) == WRITE) {
404		loff_t size = offset + count;
405
406		if (AFFS_I(inode)->mmu_private < size)
407			return 0;
408	}
409
410	ret = blockdev_direct_IO(iocb, inode, iter, affs_get_block);
411	if (ret < 0 && iov_iter_rw(iter) == WRITE)
412		affs_write_failed(mapping, offset + count);
413	return ret;
414}
415
416static int affs_write_begin(struct file *file, struct address_space *mapping,
417			loff_t pos, unsigned len, unsigned flags,
418			struct page **pagep, void **fsdata)
419{
420	int ret;
421
422	*pagep = NULL;
423	ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
424				affs_get_block,
425				&AFFS_I(mapping->host)->mmu_private);
426	if (unlikely(ret))
427		affs_write_failed(mapping, pos + len);
428
429	return ret;
430}
431
432static int affs_write_end(struct file *file, struct address_space *mapping,
433			  loff_t pos, unsigned int len, unsigned int copied,
434			  struct page *page, void *fsdata)
435{
436	struct inode *inode = mapping->host;
437	int ret;
438
439	ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
440
441	/* Clear Archived bit on file writes, as AmigaOS would do */
442	if (AFFS_I(inode)->i_protect & FIBF_ARCHIVED) {
443		AFFS_I(inode)->i_protect &= ~FIBF_ARCHIVED;
444		mark_inode_dirty(inode);
445	}
446
447	return ret;
448}
449
450static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
451{
452	return generic_block_bmap(mapping,block,affs_get_block);
453}
454
455const struct address_space_operations affs_aops = {
456	.readpage = affs_readpage,
457	.writepage = affs_writepage,
458	.write_begin = affs_write_begin,
459	.write_end = affs_write_end,
460	.direct_IO = affs_direct_IO,
461	.bmap = _affs_bmap
462};
463
464static inline struct buffer_head *
465affs_bread_ino(struct inode *inode, int block, int create)
466{
467	struct buffer_head *bh, tmp_bh;
468	int err;
469
470	tmp_bh.b_state = 0;
471	err = affs_get_block(inode, block, &tmp_bh, create);
472	if (!err) {
473		bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
474		if (bh) {
475			bh->b_state |= tmp_bh.b_state;
476			return bh;
477		}
478		err = -EIO;
479	}
480	return ERR_PTR(err);
481}
482
483static inline struct buffer_head *
484affs_getzeroblk_ino(struct inode *inode, int block)
485{
486	struct buffer_head *bh, tmp_bh;
487	int err;
488
489	tmp_bh.b_state = 0;
490	err = affs_get_block(inode, block, &tmp_bh, 1);
491	if (!err) {
492		bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
493		if (bh) {
494			bh->b_state |= tmp_bh.b_state;
495			return bh;
496		}
497		err = -EIO;
498	}
499	return ERR_PTR(err);
500}
501
502static inline struct buffer_head *
503affs_getemptyblk_ino(struct inode *inode, int block)
504{
505	struct buffer_head *bh, tmp_bh;
506	int err;
507
508	tmp_bh.b_state = 0;
509	err = affs_get_block(inode, block, &tmp_bh, 1);
510	if (!err) {
511		bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
512		if (bh) {
513			bh->b_state |= tmp_bh.b_state;
514			return bh;
515		}
516		err = -EIO;
517	}
518	return ERR_PTR(err);
519}
520
521static int
522affs_do_readpage_ofs(struct page *page, unsigned to, int create)
523{
524	struct inode *inode = page->mapping->host;
525	struct super_block *sb = inode->i_sb;
526	struct buffer_head *bh;
527	char *data;
528	unsigned pos = 0;
529	u32 bidx, boff, bsize;
530	u32 tmp;
531
532	pr_debug("%s(%lu, %ld, 0, %d)\n", __func__, inode->i_ino,
533		 page->index, to);
534	BUG_ON(to > PAGE_SIZE);
535	bsize = AFFS_SB(sb)->s_data_blksize;
536	tmp = page->index << PAGE_SHIFT;
537	bidx = tmp / bsize;
538	boff = tmp % bsize;
539
540	while (pos < to) {
541		bh = affs_bread_ino(inode, bidx, create);
542		if (IS_ERR(bh))
543			return PTR_ERR(bh);
544		tmp = min(bsize - boff, to - pos);
545		BUG_ON(pos + tmp > to || tmp > bsize);
546		data = kmap_atomic(page);
547		memcpy(data + pos, AFFS_DATA(bh) + boff, tmp);
548		kunmap_atomic(data);
549		affs_brelse(bh);
550		bidx++;
551		pos += tmp;
552		boff = 0;
553	}
554	flush_dcache_page(page);
555	return 0;
556}
557
558static int
559affs_extent_file_ofs(struct inode *inode, u32 newsize)
560{
561	struct super_block *sb = inode->i_sb;
562	struct buffer_head *bh, *prev_bh;
563	u32 bidx, boff;
564	u32 size, bsize;
565	u32 tmp;
566
567	pr_debug("%s(%lu, %d)\n", __func__, inode->i_ino, newsize);
568	bsize = AFFS_SB(sb)->s_data_blksize;
569	bh = NULL;
570	size = AFFS_I(inode)->mmu_private;
571	bidx = size / bsize;
572	boff = size % bsize;
573	if (boff) {
574		bh = affs_bread_ino(inode, bidx, 0);
575		if (IS_ERR(bh))
576			return PTR_ERR(bh);
577		tmp = min(bsize - boff, newsize - size);
578		BUG_ON(boff + tmp > bsize || tmp > bsize);
579		memset(AFFS_DATA(bh) + boff, 0, tmp);
580		be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
581		affs_fix_checksum(sb, bh);
582		mark_buffer_dirty_inode(bh, inode);
583		size += tmp;
584		bidx++;
585	} else if (bidx) {
586		bh = affs_bread_ino(inode, bidx - 1, 0);
587		if (IS_ERR(bh))
588			return PTR_ERR(bh);
589	}
590
591	while (size < newsize) {
592		prev_bh = bh;
593		bh = affs_getzeroblk_ino(inode, bidx);
594		if (IS_ERR(bh))
595			goto out;
596		tmp = min(bsize, newsize - size);
597		BUG_ON(tmp > bsize);
598		AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
599		AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
600		AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
601		AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
602		affs_fix_checksum(sb, bh);
603		bh->b_state &= ~(1UL << BH_New);
604		mark_buffer_dirty_inode(bh, inode);
605		if (prev_bh) {
606			u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
607
608			if (tmp_next)
609				affs_warning(sb, "extent_file_ofs",
610					     "next block already set for %d (%d)",
611					     bidx, tmp_next);
612			AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
613			affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
614			mark_buffer_dirty_inode(prev_bh, inode);
615			affs_brelse(prev_bh);
616		}
617		size += bsize;
618		bidx++;
619	}
620	affs_brelse(bh);
621	inode->i_size = AFFS_I(inode)->mmu_private = newsize;
622	return 0;
623
624out:
625	inode->i_size = AFFS_I(inode)->mmu_private = newsize;
626	return PTR_ERR(bh);
627}
628
629static int
630affs_readpage_ofs(struct file *file, struct page *page)
631{
632	struct inode *inode = page->mapping->host;
633	u32 to;
634	int err;
635
636	pr_debug("%s(%lu, %ld)\n", __func__, inode->i_ino, page->index);
637	to = PAGE_SIZE;
638	if (((page->index + 1) << PAGE_SHIFT) > inode->i_size) {
639		to = inode->i_size & ~PAGE_MASK;
640		memset(page_address(page) + to, 0, PAGE_SIZE - to);
641	}
642
643	err = affs_do_readpage_ofs(page, to, 0);
644	if (!err)
645		SetPageUptodate(page);
646	unlock_page(page);
647	return err;
648}
649
650static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
651				loff_t pos, unsigned len, unsigned flags,
652				struct page **pagep, void **fsdata)
653{
654	struct inode *inode = mapping->host;
655	struct page *page;
656	pgoff_t index;
657	int err = 0;
658
659	pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
660		 pos + len);
661	if (pos > AFFS_I(inode)->mmu_private) {
662		/* XXX: this probably leaves a too-big i_size in case of
663		 * failure. Should really be updating i_size at write_end time
664		 */
665		err = affs_extent_file_ofs(inode, pos);
666		if (err)
667			return err;
668	}
669
670	index = pos >> PAGE_SHIFT;
671	page = grab_cache_page_write_begin(mapping, index, flags);
672	if (!page)
673		return -ENOMEM;
674	*pagep = page;
675
676	if (PageUptodate(page))
677		return 0;
678
679	/* XXX: inefficient but safe in the face of short writes */
680	err = affs_do_readpage_ofs(page, PAGE_SIZE, 1);
681	if (err) {
682		unlock_page(page);
683		put_page(page);
684	}
685	return err;
686}
687
688static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
689				loff_t pos, unsigned len, unsigned copied,
690				struct page *page, void *fsdata)
691{
692	struct inode *inode = mapping->host;
693	struct super_block *sb = inode->i_sb;
694	struct buffer_head *bh, *prev_bh;
695	char *data;
696	u32 bidx, boff, bsize;
697	unsigned from, to;
698	u32 tmp;
699	int written;
700
701	from = pos & (PAGE_SIZE - 1);
702	to = from + len;
703	/*
704	 * XXX: not sure if this can handle short copies (len < copied), but
705	 * we don't have to, because the page should always be uptodate here,
706	 * due to write_begin.
707	 */
708
709	pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
710		 pos + len);
711	bsize = AFFS_SB(sb)->s_data_blksize;
712	data = page_address(page);
713
714	bh = NULL;
715	written = 0;
716	tmp = (page->index << PAGE_SHIFT) + from;
717	bidx = tmp / bsize;
718	boff = tmp % bsize;
719	if (boff) {
720		bh = affs_bread_ino(inode, bidx, 0);
721		if (IS_ERR(bh)) {
722			written = PTR_ERR(bh);
723			goto err_first_bh;
724		}
725		tmp = min(bsize - boff, to - from);
726		BUG_ON(boff + tmp > bsize || tmp > bsize);
727		memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
728		be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
729		affs_fix_checksum(sb, bh);
730		mark_buffer_dirty_inode(bh, inode);
731		written += tmp;
732		from += tmp;
733		bidx++;
734	} else if (bidx) {
735		bh = affs_bread_ino(inode, bidx - 1, 0);
736		if (IS_ERR(bh)) {
737			written = PTR_ERR(bh);
738			goto err_first_bh;
739		}
740	}
741	while (from + bsize <= to) {
742		prev_bh = bh;
743		bh = affs_getemptyblk_ino(inode, bidx);
744		if (IS_ERR(bh))
745			goto err_bh;
746		memcpy(AFFS_DATA(bh), data + from, bsize);
747		if (buffer_new(bh)) {
748			AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
749			AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
750			AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
751			AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
752			AFFS_DATA_HEAD(bh)->next = 0;
753			bh->b_state &= ~(1UL << BH_New);
754			if (prev_bh) {
755				u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
756
757				if (tmp_next)
758					affs_warning(sb, "commit_write_ofs",
759						     "next block already set for %d (%d)",
760						     bidx, tmp_next);
761				AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
762				affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
763				mark_buffer_dirty_inode(prev_bh, inode);
764			}
765		}
766		affs_brelse(prev_bh);
767		affs_fix_checksum(sb, bh);
768		mark_buffer_dirty_inode(bh, inode);
769		written += bsize;
770		from += bsize;
771		bidx++;
772	}
773	if (from < to) {
774		prev_bh = bh;
775		bh = affs_bread_ino(inode, bidx, 1);
776		if (IS_ERR(bh))
777			goto err_bh;
778		tmp = min(bsize, to - from);
779		BUG_ON(tmp > bsize);
780		memcpy(AFFS_DATA(bh), data + from, tmp);
781		if (buffer_new(bh)) {
782			AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
783			AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
784			AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
785			AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
786			AFFS_DATA_HEAD(bh)->next = 0;
787			bh->b_state &= ~(1UL << BH_New);
788			if (prev_bh) {
789				u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
790
791				if (tmp_next)
792					affs_warning(sb, "commit_write_ofs",
793						     "next block already set for %d (%d)",
794						     bidx, tmp_next);
795				AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
796				affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
797				mark_buffer_dirty_inode(prev_bh, inode);
798			}
799		} else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
800			AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
801		affs_brelse(prev_bh);
802		affs_fix_checksum(sb, bh);
803		mark_buffer_dirty_inode(bh, inode);
804		written += tmp;
805		from += tmp;
806		bidx++;
807	}
808	SetPageUptodate(page);
809
810done:
811	affs_brelse(bh);
812	tmp = (page->index << PAGE_SHIFT) + from;
813	if (tmp > inode->i_size)
814		inode->i_size = AFFS_I(inode)->mmu_private = tmp;
815
816	/* Clear Archived bit on file writes, as AmigaOS would do */
817	if (AFFS_I(inode)->i_protect & FIBF_ARCHIVED) {
818		AFFS_I(inode)->i_protect &= ~FIBF_ARCHIVED;
819		mark_inode_dirty(inode);
820	}
821
822err_first_bh:
823	unlock_page(page);
824	put_page(page);
825
826	return written;
827
828err_bh:
829	bh = prev_bh;
830	if (!written)
831		written = PTR_ERR(bh);
832	goto done;
833}
834
835const struct address_space_operations affs_aops_ofs = {
836	.readpage = affs_readpage_ofs,
837	//.writepage = affs_writepage_ofs,
838	.write_begin = affs_write_begin_ofs,
839	.write_end = affs_write_end_ofs
840};
841
842/* Free any preallocated blocks. */
843
844void
845affs_free_prealloc(struct inode *inode)
846{
847	struct super_block *sb = inode->i_sb;
848
849	pr_debug("free_prealloc(ino=%lu)\n", inode->i_ino);
850
851	while (AFFS_I(inode)->i_pa_cnt) {
852		AFFS_I(inode)->i_pa_cnt--;
853		affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
854	}
855}
856
857/* Truncate (or enlarge) a file to the requested size. */
858
859void
860affs_truncate(struct inode *inode)
861{
862	struct super_block *sb = inode->i_sb;
863	u32 ext, ext_key;
864	u32 last_blk, blkcnt, blk;
865	u32 size;
866	struct buffer_head *ext_bh;
867	int i;
868
869	pr_debug("truncate(inode=%lu, oldsize=%llu, newsize=%llu)\n",
870		 inode->i_ino, AFFS_I(inode)->mmu_private, inode->i_size);
871
872	last_blk = 0;
873	ext = 0;
874	if (inode->i_size) {
875		last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
876		ext = last_blk / AFFS_SB(sb)->s_hashsize;
877	}
878
879	if (inode->i_size > AFFS_I(inode)->mmu_private) {
880		struct address_space *mapping = inode->i_mapping;
881		struct page *page;
882		void *fsdata = NULL;
883		loff_t isize = inode->i_size;
884		int res;
885
886		res = mapping->a_ops->write_begin(NULL, mapping, isize, 0, 0, &page, &fsdata);
887		if (!res)
888			res = mapping->a_ops->write_end(NULL, mapping, isize, 0, 0, page, fsdata);
889		else
890			inode->i_size = AFFS_I(inode)->mmu_private;
891		mark_inode_dirty(inode);
892		return;
893	} else if (inode->i_size == AFFS_I(inode)->mmu_private)
894		return;
895
896	// lock cache
897	ext_bh = affs_get_extblock(inode, ext);
898	if (IS_ERR(ext_bh)) {
899		affs_warning(sb, "truncate",
900			     "unexpected read error for ext block %u (%ld)",
901			     ext, PTR_ERR(ext_bh));
902		return;
903	}
904	if (AFFS_I(inode)->i_lc) {
905		/* clear linear cache */
906		i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
907		if (AFFS_I(inode)->i_lc_size > i) {
908			AFFS_I(inode)->i_lc_size = i;
909			for (; i < AFFS_LC_SIZE; i++)
910				AFFS_I(inode)->i_lc[i] = 0;
911		}
912		/* clear associative cache */
913		for (i = 0; i < AFFS_AC_SIZE; i++)
914			if (AFFS_I(inode)->i_ac[i].ext >= ext)
915				AFFS_I(inode)->i_ac[i].ext = 0;
916	}
917	ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
918
919	blkcnt = AFFS_I(inode)->i_blkcnt;
920	i = 0;
921	blk = last_blk;
922	if (inode->i_size) {
923		i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
924		blk++;
925	} else
926		AFFS_HEAD(ext_bh)->first_data = 0;
927	AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
928	size = AFFS_SB(sb)->s_hashsize;
929	if (size > blkcnt - blk + i)
930		size = blkcnt - blk + i;
931	for (; i < size; i++, blk++) {
932		affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
933		AFFS_BLOCK(sb, ext_bh, i) = 0;
934	}
935	AFFS_TAIL(sb, ext_bh)->extension = 0;
936	affs_fix_checksum(sb, ext_bh);
937	mark_buffer_dirty_inode(ext_bh, inode);
938	affs_brelse(ext_bh);
939
940	if (inode->i_size) {
941		AFFS_I(inode)->i_blkcnt = last_blk + 1;
942		AFFS_I(inode)->i_extcnt = ext + 1;
943		if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS)) {
944			struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
945			u32 tmp;
946			if (IS_ERR(bh)) {
947				affs_warning(sb, "truncate",
948					     "unexpected read error for last block %u (%ld)",
949					     ext, PTR_ERR(bh));
950				return;
951			}
952			tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
953			AFFS_DATA_HEAD(bh)->next = 0;
954			affs_adjust_checksum(bh, -tmp);
955			affs_brelse(bh);
956		}
957	} else {
958		AFFS_I(inode)->i_blkcnt = 0;
959		AFFS_I(inode)->i_extcnt = 1;
960	}
961	AFFS_I(inode)->mmu_private = inode->i_size;
962	// unlock cache
963
964	while (ext_key) {
965		ext_bh = affs_bread(sb, ext_key);
966		size = AFFS_SB(sb)->s_hashsize;
967		if (size > blkcnt - blk)
968			size = blkcnt - blk;
969		for (i = 0; i < size; i++, blk++)
970			affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
971		affs_free_block(sb, ext_key);
972		ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
973		affs_brelse(ext_bh);
974	}
975	affs_free_prealloc(inode);
976}
977
978int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
979{
980	struct inode *inode = filp->f_mapping->host;
981	int ret, err;
982
983	err = file_write_and_wait_range(filp, start, end);
984	if (err)
985		return err;
986
987	inode_lock(inode);
988	ret = write_inode_now(inode, 0);
989	err = sync_blockdev(inode->i_sb->s_bdev);
990	if (!ret)
991		ret = err;
992	inode_unlock(inode);
993	return ret;
994}
995const struct file_operations affs_file_operations = {
996	.llseek		= generic_file_llseek,
997	.read_iter	= generic_file_read_iter,
998	.write_iter	= generic_file_write_iter,
999	.mmap		= generic_file_mmap,
1000	.open		= affs_file_open,
1001	.release	= affs_file_release,
1002	.fsync		= affs_file_fsync,
1003	.splice_read	= generic_file_splice_read,
1004};
1005
1006const struct inode_operations affs_file_inode_operations = {
1007	.setattr	= affs_notify_change,
1008};
1009