xref: /linux/fs/hfsplus/extents.c (revision 44f57d78) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/fs/hfsplus/extents.c
4  *
5  * Copyright (C) 2001
6  * Brad Boyer (flar@allandria.com)
7  * (C) 2003 Ardis Technologies <roman@ardistech.com>
8  *
9  * Handling of Extents both in catalog and extents overflow trees
10  */
11 
12 #include <linux/errno.h>
13 #include <linux/fs.h>
14 #include <linux/pagemap.h>
15 
16 #include "hfsplus_fs.h"
17 #include "hfsplus_raw.h"
18 
19 /* Compare two extents keys, returns 0 on same, pos/neg for difference */
20 int hfsplus_ext_cmp_key(const hfsplus_btree_key *k1,
21 			const hfsplus_btree_key *k2)
22 {
23 	__be32 k1id, k2id;
24 	__be32 k1s, k2s;
25 
26 	k1id = k1->ext.cnid;
27 	k2id = k2->ext.cnid;
28 	if (k1id != k2id)
29 		return be32_to_cpu(k1id) < be32_to_cpu(k2id) ? -1 : 1;
30 
31 	if (k1->ext.fork_type != k2->ext.fork_type)
32 		return k1->ext.fork_type < k2->ext.fork_type ? -1 : 1;
33 
34 	k1s = k1->ext.start_block;
35 	k2s = k2->ext.start_block;
36 	if (k1s == k2s)
37 		return 0;
38 	return be32_to_cpu(k1s) < be32_to_cpu(k2s) ? -1 : 1;
39 }
40 
41 static void hfsplus_ext_build_key(hfsplus_btree_key *key, u32 cnid,
42 				  u32 block, u8 type)
43 {
44 	key->key_len = cpu_to_be16(HFSPLUS_EXT_KEYLEN - 2);
45 	key->ext.cnid = cpu_to_be32(cnid);
46 	key->ext.start_block = cpu_to_be32(block);
47 	key->ext.fork_type = type;
48 	key->ext.pad = 0;
49 }
50 
51 static u32 hfsplus_ext_find_block(struct hfsplus_extent *ext, u32 off)
52 {
53 	int i;
54 	u32 count;
55 
56 	for (i = 0; i < 8; ext++, i++) {
57 		count = be32_to_cpu(ext->block_count);
58 		if (off < count)
59 			return be32_to_cpu(ext->start_block) + off;
60 		off -= count;
61 	}
62 	/* panic? */
63 	return 0;
64 }
65 
66 static int hfsplus_ext_block_count(struct hfsplus_extent *ext)
67 {
68 	int i;
69 	u32 count = 0;
70 
71 	for (i = 0; i < 8; ext++, i++)
72 		count += be32_to_cpu(ext->block_count);
73 	return count;
74 }
75 
76 static u32 hfsplus_ext_lastblock(struct hfsplus_extent *ext)
77 {
78 	int i;
79 
80 	ext += 7;
81 	for (i = 0; i < 7; ext--, i++)
82 		if (ext->block_count)
83 			break;
84 	return be32_to_cpu(ext->start_block) + be32_to_cpu(ext->block_count);
85 }
86 
87 static int __hfsplus_ext_write_extent(struct inode *inode,
88 		struct hfs_find_data *fd)
89 {
90 	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
91 	int res;
92 
93 	WARN_ON(!mutex_is_locked(&hip->extents_lock));
94 
95 	hfsplus_ext_build_key(fd->search_key, inode->i_ino, hip->cached_start,
96 			      HFSPLUS_IS_RSRC(inode) ?
97 				HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
98 
99 	res = hfs_brec_find(fd, hfs_find_rec_by_key);
100 	if (hip->extent_state & HFSPLUS_EXT_NEW) {
101 		if (res != -ENOENT)
102 			return res;
103 		/* Fail early and avoid ENOSPC during the btree operation */
104 		res = hfs_bmap_reserve(fd->tree, fd->tree->depth + 1);
105 		if (res)
106 			return res;
107 		hfs_brec_insert(fd, hip->cached_extents,
108 				sizeof(hfsplus_extent_rec));
109 		hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
110 	} else {
111 		if (res)
112 			return res;
113 		hfs_bnode_write(fd->bnode, hip->cached_extents,
114 				fd->entryoffset, fd->entrylength);
115 		hip->extent_state &= ~HFSPLUS_EXT_DIRTY;
116 	}
117 
118 	/*
119 	 * We can't just use hfsplus_mark_inode_dirty here, because we
120 	 * also get called from hfsplus_write_inode, which should not
121 	 * redirty the inode.  Instead the callers have to be careful
122 	 * to explicily mark the inode dirty, too.
123 	 */
124 	set_bit(HFSPLUS_I_EXT_DIRTY, &hip->flags);
125 
126 	return 0;
127 }
128 
129 static int hfsplus_ext_write_extent_locked(struct inode *inode)
130 {
131 	int res = 0;
132 
133 	if (HFSPLUS_I(inode)->extent_state & HFSPLUS_EXT_DIRTY) {
134 		struct hfs_find_data fd;
135 
136 		res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
137 		if (res)
138 			return res;
139 		res = __hfsplus_ext_write_extent(inode, &fd);
140 		hfs_find_exit(&fd);
141 	}
142 	return res;
143 }
144 
145 int hfsplus_ext_write_extent(struct inode *inode)
146 {
147 	int res;
148 
149 	mutex_lock(&HFSPLUS_I(inode)->extents_lock);
150 	res = hfsplus_ext_write_extent_locked(inode);
151 	mutex_unlock(&HFSPLUS_I(inode)->extents_lock);
152 
153 	return res;
154 }
155 
156 static inline int __hfsplus_ext_read_extent(struct hfs_find_data *fd,
157 					    struct hfsplus_extent *extent,
158 					    u32 cnid, u32 block, u8 type)
159 {
160 	int res;
161 
162 	hfsplus_ext_build_key(fd->search_key, cnid, block, type);
163 	fd->key->ext.cnid = 0;
164 	res = hfs_brec_find(fd, hfs_find_rec_by_key);
165 	if (res && res != -ENOENT)
166 		return res;
167 	if (fd->key->ext.cnid != fd->search_key->ext.cnid ||
168 	    fd->key->ext.fork_type != fd->search_key->ext.fork_type)
169 		return -ENOENT;
170 	if (fd->entrylength != sizeof(hfsplus_extent_rec))
171 		return -EIO;
172 	hfs_bnode_read(fd->bnode, extent, fd->entryoffset,
173 		sizeof(hfsplus_extent_rec));
174 	return 0;
175 }
176 
177 static inline int __hfsplus_ext_cache_extent(struct hfs_find_data *fd,
178 		struct inode *inode, u32 block)
179 {
180 	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
181 	int res;
182 
183 	WARN_ON(!mutex_is_locked(&hip->extents_lock));
184 
185 	if (hip->extent_state & HFSPLUS_EXT_DIRTY) {
186 		res = __hfsplus_ext_write_extent(inode, fd);
187 		if (res)
188 			return res;
189 	}
190 
191 	res = __hfsplus_ext_read_extent(fd, hip->cached_extents, inode->i_ino,
192 					block, HFSPLUS_IS_RSRC(inode) ?
193 						HFSPLUS_TYPE_RSRC :
194 						HFSPLUS_TYPE_DATA);
195 	if (!res) {
196 		hip->cached_start = be32_to_cpu(fd->key->ext.start_block);
197 		hip->cached_blocks =
198 			hfsplus_ext_block_count(hip->cached_extents);
199 	} else {
200 		hip->cached_start = hip->cached_blocks = 0;
201 		hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
202 	}
203 	return res;
204 }
205 
206 static int hfsplus_ext_read_extent(struct inode *inode, u32 block)
207 {
208 	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
209 	struct hfs_find_data fd;
210 	int res;
211 
212 	if (block >= hip->cached_start &&
213 	    block < hip->cached_start + hip->cached_blocks)
214 		return 0;
215 
216 	res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
217 	if (!res) {
218 		res = __hfsplus_ext_cache_extent(&fd, inode, block);
219 		hfs_find_exit(&fd);
220 	}
221 	return res;
222 }
223 
224 /* Get a block at iblock for inode, possibly allocating if create */
225 int hfsplus_get_block(struct inode *inode, sector_t iblock,
226 		      struct buffer_head *bh_result, int create)
227 {
228 	struct super_block *sb = inode->i_sb;
229 	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
230 	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
231 	int res = -EIO;
232 	u32 ablock, dblock, mask;
233 	sector_t sector;
234 	int was_dirty = 0;
235 
236 	/* Convert inode block to disk allocation block */
237 	ablock = iblock >> sbi->fs_shift;
238 
239 	if (iblock >= hip->fs_blocks) {
240 		if (!create)
241 			return 0;
242 		if (iblock > hip->fs_blocks)
243 			return -EIO;
244 		if (ablock >= hip->alloc_blocks) {
245 			res = hfsplus_file_extend(inode, false);
246 			if (res)
247 				return res;
248 		}
249 	} else
250 		create = 0;
251 
252 	if (ablock < hip->first_blocks) {
253 		dblock = hfsplus_ext_find_block(hip->first_extents, ablock);
254 		goto done;
255 	}
256 
257 	if (inode->i_ino == HFSPLUS_EXT_CNID)
258 		return -EIO;
259 
260 	mutex_lock(&hip->extents_lock);
261 
262 	/*
263 	 * hfsplus_ext_read_extent will write out a cached extent into
264 	 * the extents btree.  In that case we may have to mark the inode
265 	 * dirty even for a pure read of an extent here.
266 	 */
267 	was_dirty = (hip->extent_state & HFSPLUS_EXT_DIRTY);
268 	res = hfsplus_ext_read_extent(inode, ablock);
269 	if (res) {
270 		mutex_unlock(&hip->extents_lock);
271 		return -EIO;
272 	}
273 	dblock = hfsplus_ext_find_block(hip->cached_extents,
274 					ablock - hip->cached_start);
275 	mutex_unlock(&hip->extents_lock);
276 
277 done:
278 	hfs_dbg(EXTENT, "get_block(%lu): %llu - %u\n",
279 		inode->i_ino, (long long)iblock, dblock);
280 
281 	mask = (1 << sbi->fs_shift) - 1;
282 	sector = ((sector_t)dblock << sbi->fs_shift) +
283 		  sbi->blockoffset + (iblock & mask);
284 	map_bh(bh_result, sb, sector);
285 
286 	if (create) {
287 		set_buffer_new(bh_result);
288 		hip->phys_size += sb->s_blocksize;
289 		hip->fs_blocks++;
290 		inode_add_bytes(inode, sb->s_blocksize);
291 	}
292 	if (create || was_dirty)
293 		mark_inode_dirty(inode);
294 	return 0;
295 }
296 
297 static void hfsplus_dump_extent(struct hfsplus_extent *extent)
298 {
299 	int i;
300 
301 	hfs_dbg(EXTENT, "   ");
302 	for (i = 0; i < 8; i++)
303 		hfs_dbg_cont(EXTENT, " %u:%u",
304 			     be32_to_cpu(extent[i].start_block),
305 			     be32_to_cpu(extent[i].block_count));
306 	hfs_dbg_cont(EXTENT, "\n");
307 }
308 
309 static int hfsplus_add_extent(struct hfsplus_extent *extent, u32 offset,
310 			      u32 alloc_block, u32 block_count)
311 {
312 	u32 count, start;
313 	int i;
314 
315 	hfsplus_dump_extent(extent);
316 	for (i = 0; i < 8; extent++, i++) {
317 		count = be32_to_cpu(extent->block_count);
318 		if (offset == count) {
319 			start = be32_to_cpu(extent->start_block);
320 			if (alloc_block != start + count) {
321 				if (++i >= 8)
322 					return -ENOSPC;
323 				extent++;
324 				extent->start_block = cpu_to_be32(alloc_block);
325 			} else
326 				block_count += count;
327 			extent->block_count = cpu_to_be32(block_count);
328 			return 0;
329 		} else if (offset < count)
330 			break;
331 		offset -= count;
332 	}
333 	/* panic? */
334 	return -EIO;
335 }
336 
337 static int hfsplus_free_extents(struct super_block *sb,
338 				struct hfsplus_extent *extent,
339 				u32 offset, u32 block_nr)
340 {
341 	u32 count, start;
342 	int i;
343 	int err = 0;
344 
345 	/* Mapping the allocation file may lock the extent tree */
346 	WARN_ON(mutex_is_locked(&HFSPLUS_SB(sb)->ext_tree->tree_lock));
347 
348 	hfsplus_dump_extent(extent);
349 	for (i = 0; i < 8; extent++, i++) {
350 		count = be32_to_cpu(extent->block_count);
351 		if (offset == count)
352 			goto found;
353 		else if (offset < count)
354 			break;
355 		offset -= count;
356 	}
357 	/* panic? */
358 	return -EIO;
359 found:
360 	for (;;) {
361 		start = be32_to_cpu(extent->start_block);
362 		if (count <= block_nr) {
363 			err = hfsplus_block_free(sb, start, count);
364 			if (err) {
365 				pr_err("can't free extent\n");
366 				hfs_dbg(EXTENT, " start: %u count: %u\n",
367 					start, count);
368 			}
369 			extent->block_count = 0;
370 			extent->start_block = 0;
371 			block_nr -= count;
372 		} else {
373 			count -= block_nr;
374 			err = hfsplus_block_free(sb, start + count, block_nr);
375 			if (err) {
376 				pr_err("can't free extent\n");
377 				hfs_dbg(EXTENT, " start: %u count: %u\n",
378 					start, count);
379 			}
380 			extent->block_count = cpu_to_be32(count);
381 			block_nr = 0;
382 		}
383 		if (!block_nr || !i) {
384 			/*
385 			 * Try to free all extents and
386 			 * return only last error
387 			 */
388 			return err;
389 		}
390 		i--;
391 		extent--;
392 		count = be32_to_cpu(extent->block_count);
393 	}
394 }
395 
396 int hfsplus_free_fork(struct super_block *sb, u32 cnid,
397 		struct hfsplus_fork_raw *fork, int type)
398 {
399 	struct hfs_find_data fd;
400 	hfsplus_extent_rec ext_entry;
401 	u32 total_blocks, blocks, start;
402 	int res, i;
403 
404 	total_blocks = be32_to_cpu(fork->total_blocks);
405 	if (!total_blocks)
406 		return 0;
407 
408 	blocks = 0;
409 	for (i = 0; i < 8; i++)
410 		blocks += be32_to_cpu(fork->extents[i].block_count);
411 
412 	res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
413 	if (res)
414 		return res;
415 	if (total_blocks == blocks)
416 		return 0;
417 
418 	res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
419 	if (res)
420 		return res;
421 	do {
422 		res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
423 						total_blocks, type);
424 		if (res)
425 			break;
426 		start = be32_to_cpu(fd.key->ext.start_block);
427 		hfs_brec_remove(&fd);
428 
429 		mutex_unlock(&fd.tree->tree_lock);
430 		hfsplus_free_extents(sb, ext_entry, total_blocks - start,
431 				     total_blocks);
432 		total_blocks = start;
433 		mutex_lock(&fd.tree->tree_lock);
434 	} while (total_blocks > blocks);
435 	hfs_find_exit(&fd);
436 
437 	return res;
438 }
439 
440 int hfsplus_file_extend(struct inode *inode, bool zeroout)
441 {
442 	struct super_block *sb = inode->i_sb;
443 	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
444 	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
445 	u32 start, len, goal;
446 	int res;
447 
448 	if (sbi->alloc_file->i_size * 8 <
449 	    sbi->total_blocks - sbi->free_blocks + 8) {
450 		/* extend alloc file */
451 		pr_err("extend alloc file! (%llu,%u,%u)\n",
452 		       sbi->alloc_file->i_size * 8,
453 		       sbi->total_blocks, sbi->free_blocks);
454 		return -ENOSPC;
455 	}
456 
457 	mutex_lock(&hip->extents_lock);
458 	if (hip->alloc_blocks == hip->first_blocks)
459 		goal = hfsplus_ext_lastblock(hip->first_extents);
460 	else {
461 		res = hfsplus_ext_read_extent(inode, hip->alloc_blocks);
462 		if (res)
463 			goto out;
464 		goal = hfsplus_ext_lastblock(hip->cached_extents);
465 	}
466 
467 	len = hip->clump_blocks;
468 	start = hfsplus_block_allocate(sb, sbi->total_blocks, goal, &len);
469 	if (start >= sbi->total_blocks) {
470 		start = hfsplus_block_allocate(sb, goal, 0, &len);
471 		if (start >= goal) {
472 			res = -ENOSPC;
473 			goto out;
474 		}
475 	}
476 
477 	if (zeroout) {
478 		res = sb_issue_zeroout(sb, start, len, GFP_NOFS);
479 		if (res)
480 			goto out;
481 	}
482 
483 	hfs_dbg(EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len);
484 
485 	if (hip->alloc_blocks <= hip->first_blocks) {
486 		if (!hip->first_blocks) {
487 			hfs_dbg(EXTENT, "first extents\n");
488 			/* no extents yet */
489 			hip->first_extents[0].start_block = cpu_to_be32(start);
490 			hip->first_extents[0].block_count = cpu_to_be32(len);
491 			res = 0;
492 		} else {
493 			/* try to append to extents in inode */
494 			res = hfsplus_add_extent(hip->first_extents,
495 						 hip->alloc_blocks,
496 						 start, len);
497 			if (res == -ENOSPC)
498 				goto insert_extent;
499 		}
500 		if (!res) {
501 			hfsplus_dump_extent(hip->first_extents);
502 			hip->first_blocks += len;
503 		}
504 	} else {
505 		res = hfsplus_add_extent(hip->cached_extents,
506 					 hip->alloc_blocks - hip->cached_start,
507 					 start, len);
508 		if (!res) {
509 			hfsplus_dump_extent(hip->cached_extents);
510 			hip->extent_state |= HFSPLUS_EXT_DIRTY;
511 			hip->cached_blocks += len;
512 		} else if (res == -ENOSPC)
513 			goto insert_extent;
514 	}
515 out:
516 	if (!res) {
517 		hip->alloc_blocks += len;
518 		mutex_unlock(&hip->extents_lock);
519 		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
520 		return 0;
521 	}
522 	mutex_unlock(&hip->extents_lock);
523 	return res;
524 
525 insert_extent:
526 	hfs_dbg(EXTENT, "insert new extent\n");
527 	res = hfsplus_ext_write_extent_locked(inode);
528 	if (res)
529 		goto out;
530 
531 	memset(hip->cached_extents, 0, sizeof(hfsplus_extent_rec));
532 	hip->cached_extents[0].start_block = cpu_to_be32(start);
533 	hip->cached_extents[0].block_count = cpu_to_be32(len);
534 	hfsplus_dump_extent(hip->cached_extents);
535 	hip->extent_state |= HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW;
536 	hip->cached_start = hip->alloc_blocks;
537 	hip->cached_blocks = len;
538 
539 	res = 0;
540 	goto out;
541 }
542 
543 void hfsplus_file_truncate(struct inode *inode)
544 {
545 	struct super_block *sb = inode->i_sb;
546 	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
547 	struct hfs_find_data fd;
548 	u32 alloc_cnt, blk_cnt, start;
549 	int res;
550 
551 	hfs_dbg(INODE, "truncate: %lu, %llu -> %llu\n",
552 		inode->i_ino, (long long)hip->phys_size, inode->i_size);
553 
554 	if (inode->i_size > hip->phys_size) {
555 		struct address_space *mapping = inode->i_mapping;
556 		struct page *page;
557 		void *fsdata;
558 		loff_t size = inode->i_size;
559 
560 		res = pagecache_write_begin(NULL, mapping, size, 0, 0,
561 					    &page, &fsdata);
562 		if (res)
563 			return;
564 		res = pagecache_write_end(NULL, mapping, size,
565 			0, 0, page, fsdata);
566 		if (res < 0)
567 			return;
568 		mark_inode_dirty(inode);
569 		return;
570 	} else if (inode->i_size == hip->phys_size)
571 		return;
572 
573 	blk_cnt = (inode->i_size + HFSPLUS_SB(sb)->alloc_blksz - 1) >>
574 			HFSPLUS_SB(sb)->alloc_blksz_shift;
575 
576 	mutex_lock(&hip->extents_lock);
577 
578 	alloc_cnt = hip->alloc_blocks;
579 	if (blk_cnt == alloc_cnt)
580 		goto out_unlock;
581 
582 	res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
583 	if (res) {
584 		mutex_unlock(&hip->extents_lock);
585 		/* XXX: We lack error handling of hfsplus_file_truncate() */
586 		return;
587 	}
588 	while (1) {
589 		if (alloc_cnt == hip->first_blocks) {
590 			mutex_unlock(&fd.tree->tree_lock);
591 			hfsplus_free_extents(sb, hip->first_extents,
592 					     alloc_cnt, alloc_cnt - blk_cnt);
593 			hfsplus_dump_extent(hip->first_extents);
594 			hip->first_blocks = blk_cnt;
595 			mutex_lock(&fd.tree->tree_lock);
596 			break;
597 		}
598 		res = __hfsplus_ext_cache_extent(&fd, inode, alloc_cnt);
599 		if (res)
600 			break;
601 		hfs_brec_remove(&fd);
602 
603 		mutex_unlock(&fd.tree->tree_lock);
604 		start = hip->cached_start;
605 		hfsplus_free_extents(sb, hip->cached_extents,
606 				     alloc_cnt - start, alloc_cnt - blk_cnt);
607 		hfsplus_dump_extent(hip->cached_extents);
608 		if (blk_cnt > start) {
609 			hip->extent_state |= HFSPLUS_EXT_DIRTY;
610 			break;
611 		}
612 		alloc_cnt = start;
613 		hip->cached_start = hip->cached_blocks = 0;
614 		hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
615 		mutex_lock(&fd.tree->tree_lock);
616 	}
617 	hfs_find_exit(&fd);
618 
619 	hip->alloc_blocks = blk_cnt;
620 out_unlock:
621 	mutex_unlock(&hip->extents_lock);
622 	hip->phys_size = inode->i_size;
623 	hip->fs_blocks = (inode->i_size + sb->s_blocksize - 1) >>
624 		sb->s_blocksize_bits;
625 	inode_set_bytes(inode, hip->fs_blocks << sb->s_blocksize_bits);
626 	hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
627 }
628