1 /*
2  *  linux/fs/affs/file.c
3  *
4  *  (c) 1996  Hans-Joachim Widmaier - Rewritten
5  *
6  *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
7  *
8  *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
9  *
10  *  (C) 1991  Linus Torvalds - minix filesystem
11  *
12  *  affs regular file handling primitives
13  */
14 
15 #include "affs.h"
16 
17 #if PAGE_SIZE < 4096
18 #error PAGE_SIZE must be at least 4096
19 #endif
20 
21 static int affs_grow_extcache(struct inode *inode, u32 lc_idx);
22 static struct buffer_head *affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext);
23 static inline struct buffer_head *affs_get_extblock(struct inode *inode, u32 ext);
24 static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
25 static int affs_file_open(struct inode *inode, struct file *filp);
26 static int affs_file_release(struct inode *inode, struct file *filp);
27 
28 const struct file_operations affs_file_operations = {
29 	.llseek		= generic_file_llseek,
30 	.read		= do_sync_read,
31 	.aio_read	= generic_file_aio_read,
32 	.write		= do_sync_write,
33 	.aio_write	= generic_file_aio_write,
34 	.mmap		= generic_file_mmap,
35 	.open		= affs_file_open,
36 	.release	= affs_file_release,
37 	.fsync		= affs_file_fsync,
38 	.splice_read	= generic_file_splice_read,
39 };
40 
41 const struct inode_operations affs_file_inode_operations = {
42 	.truncate	= affs_truncate,
43 	.setattr	= affs_notify_change,
44 };
45 
46 static int
affs_file_open(struct inode * inode,struct file * filp)47 affs_file_open(struct inode *inode, struct file *filp)
48 {
49 	pr_debug("AFFS: open(%lu,%d)\n",
50 		 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
51 	atomic_inc(&AFFS_I(inode)->i_opencnt);
52 	return 0;
53 }
54 
55 static int
affs_file_release(struct inode * inode,struct file * filp)56 affs_file_release(struct inode *inode, struct file *filp)
57 {
58 	pr_debug("AFFS: release(%lu, %d)\n",
59 		 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
60 
61 	if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
62 		mutex_lock(&inode->i_mutex);
63 		if (inode->i_size != AFFS_I(inode)->mmu_private)
64 			affs_truncate(inode);
65 		affs_free_prealloc(inode);
66 		mutex_unlock(&inode->i_mutex);
67 	}
68 
69 	return 0;
70 }
71 
72 static int
affs_grow_extcache(struct inode * inode,u32 lc_idx)73 affs_grow_extcache(struct inode *inode, u32 lc_idx)
74 {
75 	struct super_block	*sb = inode->i_sb;
76 	struct buffer_head	*bh;
77 	u32 lc_max;
78 	int i, j, key;
79 
80 	if (!AFFS_I(inode)->i_lc) {
81 		char *ptr = (char *)get_zeroed_page(GFP_NOFS);
82 		if (!ptr)
83 			return -ENOMEM;
84 		AFFS_I(inode)->i_lc = (u32 *)ptr;
85 		AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
86 	}
87 
88 	lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
89 
90 	if (AFFS_I(inode)->i_extcnt > lc_max) {
91 		u32 lc_shift, lc_mask, tmp, off;
92 
93 		/* need to recalculate linear cache, start from old size */
94 		lc_shift = AFFS_I(inode)->i_lc_shift;
95 		tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
96 		for (; tmp; tmp >>= 1)
97 			lc_shift++;
98 		lc_mask = (1 << lc_shift) - 1;
99 
100 		/* fix idx and old size to new shift */
101 		lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
102 		AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
103 
104 		/* first shrink old cache to make more space */
105 		off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
106 		for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
107 			AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
108 
109 		AFFS_I(inode)->i_lc_shift = lc_shift;
110 		AFFS_I(inode)->i_lc_mask = lc_mask;
111 	}
112 
113 	/* fill cache to the needed index */
114 	i = AFFS_I(inode)->i_lc_size;
115 	AFFS_I(inode)->i_lc_size = lc_idx + 1;
116 	for (; i <= lc_idx; i++) {
117 		if (!i) {
118 			AFFS_I(inode)->i_lc[0] = inode->i_ino;
119 			continue;
120 		}
121 		key = AFFS_I(inode)->i_lc[i - 1];
122 		j = AFFS_I(inode)->i_lc_mask + 1;
123 		// unlock cache
124 		for (; j > 0; j--) {
125 			bh = affs_bread(sb, key);
126 			if (!bh)
127 				goto err;
128 			key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
129 			affs_brelse(bh);
130 		}
131 		// lock cache
132 		AFFS_I(inode)->i_lc[i] = key;
133 	}
134 
135 	return 0;
136 
137 err:
138 	// lock cache
139 	return -EIO;
140 }
141 
142 static struct buffer_head *
affs_alloc_extblock(struct inode * inode,struct buffer_head * bh,u32 ext)143 affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
144 {
145 	struct super_block *sb = inode->i_sb;
146 	struct buffer_head *new_bh;
147 	u32 blocknr, tmp;
148 
149 	blocknr = affs_alloc_block(inode, bh->b_blocknr);
150 	if (!blocknr)
151 		return ERR_PTR(-ENOSPC);
152 
153 	new_bh = affs_getzeroblk(sb, blocknr);
154 	if (!new_bh) {
155 		affs_free_block(sb, blocknr);
156 		return ERR_PTR(-EIO);
157 	}
158 
159 	AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
160 	AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
161 	AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
162 	AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
163 	affs_fix_checksum(sb, new_bh);
164 
165 	mark_buffer_dirty_inode(new_bh, inode);
166 
167 	tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
168 	if (tmp)
169 		affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
170 	AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
171 	affs_adjust_checksum(bh, blocknr - tmp);
172 	mark_buffer_dirty_inode(bh, inode);
173 
174 	AFFS_I(inode)->i_extcnt++;
175 	mark_inode_dirty(inode);
176 
177 	return new_bh;
178 }
179 
180 static inline struct buffer_head *
affs_get_extblock(struct inode * inode,u32 ext)181 affs_get_extblock(struct inode *inode, u32 ext)
182 {
183 	/* inline the simplest case: same extended block as last time */
184 	struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
185 	if (ext == AFFS_I(inode)->i_ext_last)
186 		get_bh(bh);
187 	else
188 		/* we have to do more (not inlined) */
189 		bh = affs_get_extblock_slow(inode, ext);
190 
191 	return bh;
192 }
193 
194 static struct buffer_head *
affs_get_extblock_slow(struct inode * inode,u32 ext)195 affs_get_extblock_slow(struct inode *inode, u32 ext)
196 {
197 	struct super_block *sb = inode->i_sb;
198 	struct buffer_head *bh;
199 	u32 ext_key;
200 	u32 lc_idx, lc_off, ac_idx;
201 	u32 tmp, idx;
202 
203 	if (ext == AFFS_I(inode)->i_ext_last + 1) {
204 		/* read the next extended block from the current one */
205 		bh = AFFS_I(inode)->i_ext_bh;
206 		ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
207 		if (ext < AFFS_I(inode)->i_extcnt)
208 			goto read_ext;
209 		if (ext > AFFS_I(inode)->i_extcnt)
210 			BUG();
211 		bh = affs_alloc_extblock(inode, bh, ext);
212 		if (IS_ERR(bh))
213 			return bh;
214 		goto store_ext;
215 	}
216 
217 	if (ext == 0) {
218 		/* we seek back to the file header block */
219 		ext_key = inode->i_ino;
220 		goto read_ext;
221 	}
222 
223 	if (ext >= AFFS_I(inode)->i_extcnt) {
224 		struct buffer_head *prev_bh;
225 
226 		/* allocate a new extended block */
227 		if (ext > AFFS_I(inode)->i_extcnt)
228 			BUG();
229 
230 		/* get previous extended block */
231 		prev_bh = affs_get_extblock(inode, ext - 1);
232 		if (IS_ERR(prev_bh))
233 			return prev_bh;
234 		bh = affs_alloc_extblock(inode, prev_bh, ext);
235 		affs_brelse(prev_bh);
236 		if (IS_ERR(bh))
237 			return bh;
238 		goto store_ext;
239 	}
240 
241 again:
242 	/* check if there is an extended cache and whether it's large enough */
243 	lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
244 	lc_off = ext & AFFS_I(inode)->i_lc_mask;
245 
246 	if (lc_idx >= AFFS_I(inode)->i_lc_size) {
247 		int err;
248 
249 		err = affs_grow_extcache(inode, lc_idx);
250 		if (err)
251 			return ERR_PTR(err);
252 		goto again;
253 	}
254 
255 	/* every n'th key we find in the linear cache */
256 	if (!lc_off) {
257 		ext_key = AFFS_I(inode)->i_lc[lc_idx];
258 		goto read_ext;
259 	}
260 
261 	/* maybe it's still in the associative cache */
262 	ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
263 	if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
264 		ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
265 		goto read_ext;
266 	}
267 
268 	/* try to find one of the previous extended blocks */
269 	tmp = ext;
270 	idx = ac_idx;
271 	while (--tmp, --lc_off > 0) {
272 		idx = (idx - 1) & AFFS_AC_MASK;
273 		if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
274 			ext_key = AFFS_I(inode)->i_ac[idx].key;
275 			goto find_ext;
276 		}
277 	}
278 
279 	/* fall back to the linear cache */
280 	ext_key = AFFS_I(inode)->i_lc[lc_idx];
281 find_ext:
282 	/* read all extended blocks until we find the one we need */
283 	//unlock cache
284 	do {
285 		bh = affs_bread(sb, ext_key);
286 		if (!bh)
287 			goto err_bread;
288 		ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
289 		affs_brelse(bh);
290 		tmp++;
291 	} while (tmp < ext);
292 	//lock cache
293 
294 	/* store it in the associative cache */
295 	// recalculate ac_idx?
296 	AFFS_I(inode)->i_ac[ac_idx].ext = ext;
297 	AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
298 
299 read_ext:
300 	/* finally read the right extended block */
301 	//unlock cache
302 	bh = affs_bread(sb, ext_key);
303 	if (!bh)
304 		goto err_bread;
305 	//lock cache
306 
307 store_ext:
308 	/* release old cached extended block and store the new one */
309 	affs_brelse(AFFS_I(inode)->i_ext_bh);
310 	AFFS_I(inode)->i_ext_last = ext;
311 	AFFS_I(inode)->i_ext_bh = bh;
312 	get_bh(bh);
313 
314 	return bh;
315 
316 err_bread:
317 	affs_brelse(bh);
318 	return ERR_PTR(-EIO);
319 }
320 
321 static int
affs_get_block(struct inode * inode,sector_t block,struct buffer_head * bh_result,int create)322 affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
323 {
324 	struct super_block	*sb = inode->i_sb;
325 	struct buffer_head	*ext_bh;
326 	u32			 ext;
327 
328 	pr_debug("AFFS: get_block(%u, %lu)\n", (u32)inode->i_ino, (unsigned long)block);
329 
330 	BUG_ON(block > (sector_t)0x7fffffffUL);
331 
332 	if (block >= AFFS_I(inode)->i_blkcnt) {
333 		if (block > AFFS_I(inode)->i_blkcnt || !create)
334 			goto err_big;
335 	} else
336 		create = 0;
337 
338 	//lock cache
339 	affs_lock_ext(inode);
340 
341 	ext = (u32)block / AFFS_SB(sb)->s_hashsize;
342 	block -= ext * AFFS_SB(sb)->s_hashsize;
343 	ext_bh = affs_get_extblock(inode, ext);
344 	if (IS_ERR(ext_bh))
345 		goto err_ext;
346 	map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
347 
348 	if (create) {
349 		u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
350 		if (!blocknr)
351 			goto err_alloc;
352 		set_buffer_new(bh_result);
353 		AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
354 		AFFS_I(inode)->i_blkcnt++;
355 
356 		/* store new block */
357 		if (bh_result->b_blocknr)
358 			affs_warning(sb, "get_block", "block already set (%x)", bh_result->b_blocknr);
359 		AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
360 		AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
361 		affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
362 		bh_result->b_blocknr = blocknr;
363 
364 		if (!block) {
365 			/* insert first block into header block */
366 			u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
367 			if (tmp)
368 				affs_warning(sb, "get_block", "first block already set (%d)", tmp);
369 			AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
370 			affs_adjust_checksum(ext_bh, blocknr - tmp);
371 		}
372 	}
373 
374 	affs_brelse(ext_bh);
375 	//unlock cache
376 	affs_unlock_ext(inode);
377 	return 0;
378 
379 err_big:
380 	affs_error(inode->i_sb,"get_block","strange block request %d", block);
381 	return -EIO;
382 err_ext:
383 	// unlock cache
384 	affs_unlock_ext(inode);
385 	return PTR_ERR(ext_bh);
386 err_alloc:
387 	brelse(ext_bh);
388 	clear_buffer_mapped(bh_result);
389 	bh_result->b_bdev = NULL;
390 	// unlock cache
391 	affs_unlock_ext(inode);
392 	return -ENOSPC;
393 }
394 
affs_writepage(struct page * page,struct writeback_control * wbc)395 static int affs_writepage(struct page *page, struct writeback_control *wbc)
396 {
397 	return block_write_full_page(page, affs_get_block, wbc);
398 }
399 
affs_readpage(struct file * file,struct page * page)400 static int affs_readpage(struct file *file, struct page *page)
401 {
402 	return block_read_full_page(page, affs_get_block);
403 }
404 
affs_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned flags,struct page ** pagep,void ** fsdata)405 static int affs_write_begin(struct file *file, struct address_space *mapping,
406 			loff_t pos, unsigned len, unsigned flags,
407 			struct page **pagep, void **fsdata)
408 {
409 	int ret;
410 
411 	*pagep = NULL;
412 	ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
413 				affs_get_block,
414 				&AFFS_I(mapping->host)->mmu_private);
415 	if (unlikely(ret)) {
416 		loff_t isize = mapping->host->i_size;
417 		if (pos + len > isize)
418 			vmtruncate(mapping->host, isize);
419 	}
420 
421 	return ret;
422 }
423 
_affs_bmap(struct address_space * mapping,sector_t block)424 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
425 {
426 	return generic_block_bmap(mapping,block,affs_get_block);
427 }
428 
429 const struct address_space_operations affs_aops = {
430 	.readpage = affs_readpage,
431 	.writepage = affs_writepage,
432 	.write_begin = affs_write_begin,
433 	.write_end = generic_write_end,
434 	.bmap = _affs_bmap
435 };
436 
437 static inline struct buffer_head *
affs_bread_ino(struct inode * inode,int block,int create)438 affs_bread_ino(struct inode *inode, int block, int create)
439 {
440 	struct buffer_head *bh, tmp_bh;
441 	int err;
442 
443 	tmp_bh.b_state = 0;
444 	err = affs_get_block(inode, block, &tmp_bh, create);
445 	if (!err) {
446 		bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
447 		if (bh) {
448 			bh->b_state |= tmp_bh.b_state;
449 			return bh;
450 		}
451 		err = -EIO;
452 	}
453 	return ERR_PTR(err);
454 }
455 
456 static inline struct buffer_head *
affs_getzeroblk_ino(struct inode * inode,int block)457 affs_getzeroblk_ino(struct inode *inode, int block)
458 {
459 	struct buffer_head *bh, tmp_bh;
460 	int err;
461 
462 	tmp_bh.b_state = 0;
463 	err = affs_get_block(inode, block, &tmp_bh, 1);
464 	if (!err) {
465 		bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
466 		if (bh) {
467 			bh->b_state |= tmp_bh.b_state;
468 			return bh;
469 		}
470 		err = -EIO;
471 	}
472 	return ERR_PTR(err);
473 }
474 
475 static inline struct buffer_head *
affs_getemptyblk_ino(struct inode * inode,int block)476 affs_getemptyblk_ino(struct inode *inode, int block)
477 {
478 	struct buffer_head *bh, tmp_bh;
479 	int err;
480 
481 	tmp_bh.b_state = 0;
482 	err = affs_get_block(inode, block, &tmp_bh, 1);
483 	if (!err) {
484 		bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
485 		if (bh) {
486 			bh->b_state |= tmp_bh.b_state;
487 			return bh;
488 		}
489 		err = -EIO;
490 	}
491 	return ERR_PTR(err);
492 }
493 
494 static int
affs_do_readpage_ofs(struct file * file,struct page * page,unsigned from,unsigned to)495 affs_do_readpage_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
496 {
497 	struct inode *inode = page->mapping->host;
498 	struct super_block *sb = inode->i_sb;
499 	struct buffer_head *bh;
500 	char *data;
501 	u32 bidx, boff, bsize;
502 	u32 tmp;
503 
504 	pr_debug("AFFS: read_page(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
505 	BUG_ON(from > to || to > PAGE_CACHE_SIZE);
506 	kmap(page);
507 	data = page_address(page);
508 	bsize = AFFS_SB(sb)->s_data_blksize;
509 	tmp = (page->index << PAGE_CACHE_SHIFT) + from;
510 	bidx = tmp / bsize;
511 	boff = tmp % bsize;
512 
513 	while (from < to) {
514 		bh = affs_bread_ino(inode, bidx, 0);
515 		if (IS_ERR(bh))
516 			return PTR_ERR(bh);
517 		tmp = min(bsize - boff, to - from);
518 		BUG_ON(from + tmp > to || tmp > bsize);
519 		memcpy(data + from, AFFS_DATA(bh) + boff, tmp);
520 		affs_brelse(bh);
521 		bidx++;
522 		from += tmp;
523 		boff = 0;
524 	}
525 	flush_dcache_page(page);
526 	kunmap(page);
527 	return 0;
528 }
529 
530 static int
affs_extent_file_ofs(struct inode * inode,u32 newsize)531 affs_extent_file_ofs(struct inode *inode, u32 newsize)
532 {
533 	struct super_block *sb = inode->i_sb;
534 	struct buffer_head *bh, *prev_bh;
535 	u32 bidx, boff;
536 	u32 size, bsize;
537 	u32 tmp;
538 
539 	pr_debug("AFFS: extent_file(%u, %d)\n", (u32)inode->i_ino, newsize);
540 	bsize = AFFS_SB(sb)->s_data_blksize;
541 	bh = NULL;
542 	size = AFFS_I(inode)->mmu_private;
543 	bidx = size / bsize;
544 	boff = size % bsize;
545 	if (boff) {
546 		bh = affs_bread_ino(inode, bidx, 0);
547 		if (IS_ERR(bh))
548 			return PTR_ERR(bh);
549 		tmp = min(bsize - boff, newsize - size);
550 		BUG_ON(boff + tmp > bsize || tmp > bsize);
551 		memset(AFFS_DATA(bh) + boff, 0, tmp);
552 		be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
553 		affs_fix_checksum(sb, bh);
554 		mark_buffer_dirty_inode(bh, inode);
555 		size += tmp;
556 		bidx++;
557 	} else if (bidx) {
558 		bh = affs_bread_ino(inode, bidx - 1, 0);
559 		if (IS_ERR(bh))
560 			return PTR_ERR(bh);
561 	}
562 
563 	while (size < newsize) {
564 		prev_bh = bh;
565 		bh = affs_getzeroblk_ino(inode, bidx);
566 		if (IS_ERR(bh))
567 			goto out;
568 		tmp = min(bsize, newsize - size);
569 		BUG_ON(tmp > bsize);
570 		AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
571 		AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
572 		AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
573 		AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
574 		affs_fix_checksum(sb, bh);
575 		bh->b_state &= ~(1UL << BH_New);
576 		mark_buffer_dirty_inode(bh, inode);
577 		if (prev_bh) {
578 			u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
579 			if (tmp)
580 				affs_warning(sb, "extent_file_ofs", "next block already set for %d (%d)", bidx, tmp);
581 			AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
582 			affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
583 			mark_buffer_dirty_inode(prev_bh, inode);
584 			affs_brelse(prev_bh);
585 		}
586 		size += bsize;
587 		bidx++;
588 	}
589 	affs_brelse(bh);
590 	inode->i_size = AFFS_I(inode)->mmu_private = newsize;
591 	return 0;
592 
593 out:
594 	inode->i_size = AFFS_I(inode)->mmu_private = newsize;
595 	return PTR_ERR(bh);
596 }
597 
598 static int
affs_readpage_ofs(struct file * file,struct page * page)599 affs_readpage_ofs(struct file *file, struct page *page)
600 {
601 	struct inode *inode = page->mapping->host;
602 	u32 to;
603 	int err;
604 
605 	pr_debug("AFFS: read_page(%u, %ld)\n", (u32)inode->i_ino, page->index);
606 	to = PAGE_CACHE_SIZE;
607 	if (((page->index + 1) << PAGE_CACHE_SHIFT) > inode->i_size) {
608 		to = inode->i_size & ~PAGE_CACHE_MASK;
609 		memset(page_address(page) + to, 0, PAGE_CACHE_SIZE - to);
610 	}
611 
612 	err = affs_do_readpage_ofs(file, page, 0, to);
613 	if (!err)
614 		SetPageUptodate(page);
615 	unlock_page(page);
616 	return err;
617 }
618 
affs_write_begin_ofs(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned flags,struct page ** pagep,void ** fsdata)619 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
620 				loff_t pos, unsigned len, unsigned flags,
621 				struct page **pagep, void **fsdata)
622 {
623 	struct inode *inode = mapping->host;
624 	struct page *page;
625 	pgoff_t index;
626 	int err = 0;
627 
628 	pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
629 	if (pos > AFFS_I(inode)->mmu_private) {
630 		/* XXX: this probably leaves a too-big i_size in case of
631 		 * failure. Should really be updating i_size at write_end time
632 		 */
633 		err = affs_extent_file_ofs(inode, pos);
634 		if (err)
635 			return err;
636 	}
637 
638 	index = pos >> PAGE_CACHE_SHIFT;
639 	page = grab_cache_page_write_begin(mapping, index, flags);
640 	if (!page)
641 		return -ENOMEM;
642 	*pagep = page;
643 
644 	if (PageUptodate(page))
645 		return 0;
646 
647 	/* XXX: inefficient but safe in the face of short writes */
648 	err = affs_do_readpage_ofs(file, page, 0, PAGE_CACHE_SIZE);
649 	if (err) {
650 		unlock_page(page);
651 		page_cache_release(page);
652 	}
653 	return err;
654 }
655 
affs_write_end_ofs(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * page,void * fsdata)656 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
657 				loff_t pos, unsigned len, unsigned copied,
658 				struct page *page, void *fsdata)
659 {
660 	struct inode *inode = mapping->host;
661 	struct super_block *sb = inode->i_sb;
662 	struct buffer_head *bh, *prev_bh;
663 	char *data;
664 	u32 bidx, boff, bsize;
665 	unsigned from, to;
666 	u32 tmp;
667 	int written;
668 
669 	from = pos & (PAGE_CACHE_SIZE - 1);
670 	to = pos + len;
671 	/*
672 	 * XXX: not sure if this can handle short copies (len < copied), but
673 	 * we don't have to, because the page should always be uptodate here,
674 	 * due to write_begin.
675 	 */
676 
677 	pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
678 	bsize = AFFS_SB(sb)->s_data_blksize;
679 	data = page_address(page);
680 
681 	bh = NULL;
682 	written = 0;
683 	tmp = (page->index << PAGE_CACHE_SHIFT) + from;
684 	bidx = tmp / bsize;
685 	boff = tmp % bsize;
686 	if (boff) {
687 		bh = affs_bread_ino(inode, bidx, 0);
688 		if (IS_ERR(bh))
689 			return PTR_ERR(bh);
690 		tmp = min(bsize - boff, to - from);
691 		BUG_ON(boff + tmp > bsize || tmp > bsize);
692 		memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
693 		be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
694 		affs_fix_checksum(sb, bh);
695 		mark_buffer_dirty_inode(bh, inode);
696 		written += tmp;
697 		from += tmp;
698 		bidx++;
699 	} else if (bidx) {
700 		bh = affs_bread_ino(inode, bidx - 1, 0);
701 		if (IS_ERR(bh))
702 			return PTR_ERR(bh);
703 	}
704 	while (from + bsize <= to) {
705 		prev_bh = bh;
706 		bh = affs_getemptyblk_ino(inode, bidx);
707 		if (IS_ERR(bh))
708 			goto out;
709 		memcpy(AFFS_DATA(bh), data + from, bsize);
710 		if (buffer_new(bh)) {
711 			AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
712 			AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
713 			AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
714 			AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
715 			AFFS_DATA_HEAD(bh)->next = 0;
716 			bh->b_state &= ~(1UL << BH_New);
717 			if (prev_bh) {
718 				u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
719 				if (tmp)
720 					affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
721 				AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
722 				affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
723 				mark_buffer_dirty_inode(prev_bh, inode);
724 			}
725 		}
726 		affs_brelse(prev_bh);
727 		affs_fix_checksum(sb, bh);
728 		mark_buffer_dirty_inode(bh, inode);
729 		written += bsize;
730 		from += bsize;
731 		bidx++;
732 	}
733 	if (from < to) {
734 		prev_bh = bh;
735 		bh = affs_bread_ino(inode, bidx, 1);
736 		if (IS_ERR(bh))
737 			goto out;
738 		tmp = min(bsize, to - from);
739 		BUG_ON(tmp > bsize);
740 		memcpy(AFFS_DATA(bh), data + from, tmp);
741 		if (buffer_new(bh)) {
742 			AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
743 			AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
744 			AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
745 			AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
746 			AFFS_DATA_HEAD(bh)->next = 0;
747 			bh->b_state &= ~(1UL << BH_New);
748 			if (prev_bh) {
749 				u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
750 				if (tmp)
751 					affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
752 				AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
753 				affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
754 				mark_buffer_dirty_inode(prev_bh, inode);
755 			}
756 		} else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
757 			AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
758 		affs_brelse(prev_bh);
759 		affs_fix_checksum(sb, bh);
760 		mark_buffer_dirty_inode(bh, inode);
761 		written += tmp;
762 		from += tmp;
763 		bidx++;
764 	}
765 	SetPageUptodate(page);
766 
767 done:
768 	affs_brelse(bh);
769 	tmp = (page->index << PAGE_CACHE_SHIFT) + from;
770 	if (tmp > inode->i_size)
771 		inode->i_size = AFFS_I(inode)->mmu_private = tmp;
772 
773 	unlock_page(page);
774 	page_cache_release(page);
775 
776 	return written;
777 
778 out:
779 	bh = prev_bh;
780 	if (!written)
781 		written = PTR_ERR(bh);
782 	goto done;
783 }
784 
785 const struct address_space_operations affs_aops_ofs = {
786 	.readpage = affs_readpage_ofs,
787 	//.writepage = affs_writepage_ofs,
788 	.write_begin = affs_write_begin_ofs,
789 	.write_end = affs_write_end_ofs
790 };
791 
792 /* Free any preallocated blocks. */
793 
794 void
affs_free_prealloc(struct inode * inode)795 affs_free_prealloc(struct inode *inode)
796 {
797 	struct super_block *sb = inode->i_sb;
798 
799 	pr_debug("AFFS: free_prealloc(ino=%lu)\n", inode->i_ino);
800 
801 	while (AFFS_I(inode)->i_pa_cnt) {
802 		AFFS_I(inode)->i_pa_cnt--;
803 		affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
804 	}
805 }
806 
807 /* Truncate (or enlarge) a file to the requested size. */
808 
809 void
affs_truncate(struct inode * inode)810 affs_truncate(struct inode *inode)
811 {
812 	struct super_block *sb = inode->i_sb;
813 	u32 ext, ext_key;
814 	u32 last_blk, blkcnt, blk;
815 	u32 size;
816 	struct buffer_head *ext_bh;
817 	int i;
818 
819 	pr_debug("AFFS: truncate(inode=%d, oldsize=%u, newsize=%u)\n",
820 		 (u32)inode->i_ino, (u32)AFFS_I(inode)->mmu_private, (u32)inode->i_size);
821 
822 	last_blk = 0;
823 	ext = 0;
824 	if (inode->i_size) {
825 		last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
826 		ext = last_blk / AFFS_SB(sb)->s_hashsize;
827 	}
828 
829 	if (inode->i_size > AFFS_I(inode)->mmu_private) {
830 		struct address_space *mapping = inode->i_mapping;
831 		struct page *page;
832 		void *fsdata;
833 		u32 size = inode->i_size;
834 		int res;
835 
836 		res = mapping->a_ops->write_begin(NULL, mapping, size, 0, 0, &page, &fsdata);
837 		if (!res)
838 			res = mapping->a_ops->write_end(NULL, mapping, size, 0, 0, page, fsdata);
839 		else
840 			inode->i_size = AFFS_I(inode)->mmu_private;
841 		mark_inode_dirty(inode);
842 		return;
843 	} else if (inode->i_size == AFFS_I(inode)->mmu_private)
844 		return;
845 
846 	// lock cache
847 	ext_bh = affs_get_extblock(inode, ext);
848 	if (IS_ERR(ext_bh)) {
849 		affs_warning(sb, "truncate", "unexpected read error for ext block %u (%d)",
850 			     ext, PTR_ERR(ext_bh));
851 		return;
852 	}
853 	if (AFFS_I(inode)->i_lc) {
854 		/* clear linear cache */
855 		i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
856 		if (AFFS_I(inode)->i_lc_size > i) {
857 			AFFS_I(inode)->i_lc_size = i;
858 			for (; i < AFFS_LC_SIZE; i++)
859 				AFFS_I(inode)->i_lc[i] = 0;
860 		}
861 		/* clear associative cache */
862 		for (i = 0; i < AFFS_AC_SIZE; i++)
863 			if (AFFS_I(inode)->i_ac[i].ext >= ext)
864 				AFFS_I(inode)->i_ac[i].ext = 0;
865 	}
866 	ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
867 
868 	blkcnt = AFFS_I(inode)->i_blkcnt;
869 	i = 0;
870 	blk = last_blk;
871 	if (inode->i_size) {
872 		i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
873 		blk++;
874 	} else
875 		AFFS_HEAD(ext_bh)->first_data = 0;
876 	AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
877 	size = AFFS_SB(sb)->s_hashsize;
878 	if (size > blkcnt - blk + i)
879 		size = blkcnt - blk + i;
880 	for (; i < size; i++, blk++) {
881 		affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
882 		AFFS_BLOCK(sb, ext_bh, i) = 0;
883 	}
884 	AFFS_TAIL(sb, ext_bh)->extension = 0;
885 	affs_fix_checksum(sb, ext_bh);
886 	mark_buffer_dirty_inode(ext_bh, inode);
887 	affs_brelse(ext_bh);
888 
889 	if (inode->i_size) {
890 		AFFS_I(inode)->i_blkcnt = last_blk + 1;
891 		AFFS_I(inode)->i_extcnt = ext + 1;
892 		if (AFFS_SB(sb)->s_flags & SF_OFS) {
893 			struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
894 			u32 tmp;
895 			if (IS_ERR(bh)) {
896 				affs_warning(sb, "truncate", "unexpected read error for last block %u (%d)",
897 					     ext, PTR_ERR(bh));
898 				return;
899 			}
900 			tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
901 			AFFS_DATA_HEAD(bh)->next = 0;
902 			affs_adjust_checksum(bh, -tmp);
903 			affs_brelse(bh);
904 		}
905 	} else {
906 		AFFS_I(inode)->i_blkcnt = 0;
907 		AFFS_I(inode)->i_extcnt = 1;
908 	}
909 	AFFS_I(inode)->mmu_private = inode->i_size;
910 	// unlock cache
911 
912 	while (ext_key) {
913 		ext_bh = affs_bread(sb, ext_key);
914 		size = AFFS_SB(sb)->s_hashsize;
915 		if (size > blkcnt - blk)
916 			size = blkcnt - blk;
917 		for (i = 0; i < size; i++, blk++)
918 			affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
919 		affs_free_block(sb, ext_key);
920 		ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
921 		affs_brelse(ext_bh);
922 	}
923 	affs_free_prealloc(inode);
924 }
925 
affs_file_fsync(struct file * filp,loff_t start,loff_t end,int datasync)926 int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
927 {
928 	struct inode *inode = filp->f_mapping->host;
929 	int ret, err;
930 
931 	err = filemap_write_and_wait_range(inode->i_mapping, start, end);
932 	if (err)
933 		return err;
934 
935 	mutex_lock(&inode->i_mutex);
936 	ret = write_inode_now(inode, 0);
937 	err = sync_blockdev(inode->i_sb->s_bdev);
938 	if (!ret)
939 		ret = err;
940 	mutex_unlock(&inode->i_mutex);
941 	return ret;
942 }
943