extents.c

  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 */
 20int 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
 41static 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
 51static 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
 66static 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
 76static 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
 87static 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
129static 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
145int 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
156static 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
177static 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
206static 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 */
225int 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
277done:
278	hfs_dbg("ino %lu, iblock %llu - dblock %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
297static 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(" start_block %u, block_count %u",
304			be32_to_cpu(extent[i].start_block),
305			be32_to_cpu(extent[i].block_count));
306	hfs_dbg("\n");
307}
308
309static 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
337static 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	hfsplus_dump_extent(extent);
346	for (i = 0; i < 8; extent++, i++) {
347		count = be32_to_cpu(extent->block_count);
348		if (offset == count)
349			goto found;
350		else if (offset < count)
351			break;
352		offset -= count;
353	}
354	/* panic? */
355	return -EIO;
356found:
357	for (;;) {
358		start = be32_to_cpu(extent->start_block);
359		if (count <= block_nr) {
360			err = hfsplus_block_free(sb, start, count);
361			if (err) {
362				pr_err("can't free extent: start %u, count %u\n",
363					start, count);
364			}
365			extent->block_count = 0;
366			extent->start_block = 0;
367			block_nr -= count;
368		} else {
369			count -= block_nr;
370			err = hfsplus_block_free(sb, start + count, block_nr);
371			if (err) {
372				pr_err("can't free extent: start %u, count %u\n",
373					start, count);
374			}
375			extent->block_count = cpu_to_be32(count);
376			block_nr = 0;
377		}
378		if (!block_nr || !i) {
379			/*
380			 * Try to free all extents and
381			 * return only last error
382			 */
383			return err;
384		}
385		i--;
386		extent--;
387		count = be32_to_cpu(extent->block_count);
388	}
389}
390
391int hfsplus_free_fork(struct super_block *sb, u32 cnid,
392		struct hfsplus_fork_raw *fork, int type)
393{
394	struct hfs_find_data fd;
395	hfsplus_extent_rec ext_entry;
396	u32 total_blocks, blocks, start;
397	int res, i;
398
399	total_blocks = be32_to_cpu(fork->total_blocks);
400	if (!total_blocks)
401		return 0;
402
403	blocks = 0;
404	for (i = 0; i < 8; i++)
405		blocks += be32_to_cpu(fork->extents[i].block_count);
406
407	res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
408	if (res)
409		return res;
410	if (total_blocks == blocks)
411		return 0;
412
413	res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
414	if (res)
415		return res;
416	do {
417		res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
418						total_blocks, type);
419		if (res)
420			break;
421		start = be32_to_cpu(fd.key->ext.start_block);
422		hfs_brec_remove(&fd);
423
424		mutex_unlock(&fd.tree->tree_lock);
425		hfsplus_free_extents(sb, ext_entry, total_blocks - start,
426				     total_blocks);
427		total_blocks = start;
428		mutex_lock_nested(&fd.tree->tree_lock,
429			hfsplus_btree_lock_class(fd.tree));
430	} while (total_blocks > blocks);
431	hfs_find_exit(&fd);
432
433	return res;
434}
435
436int hfsplus_file_extend(struct inode *inode, bool zeroout)
437{
438	struct super_block *sb = inode->i_sb;
439	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
440	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
441	u32 start, len, goal;
442	int res;
443
444	if (sbi->alloc_file->i_size * 8 <
445	    sbi->total_blocks - sbi->free_blocks + 8) {
446		/* extend alloc file */
447		pr_err_ratelimited("extend alloc file! (%llu,%u,%u)\n",
448				   sbi->alloc_file->i_size * 8,
449				   sbi->total_blocks, sbi->free_blocks);
450		return -ENOSPC;
451	}
452
453	mutex_lock(&hip->extents_lock);
454	if (hip->alloc_blocks == hip->first_blocks)
455		goal = hfsplus_ext_lastblock(hip->first_extents);
456	else {
457		res = hfsplus_ext_read_extent(inode, hip->alloc_blocks);
458		if (res)
459			goto out;
460		goal = hfsplus_ext_lastblock(hip->cached_extents);
461	}
462
463	len = hip->clump_blocks;
464	start = hfsplus_block_allocate(sb, sbi->total_blocks, goal, &len);
465	if (start >= sbi->total_blocks) {
466		start = hfsplus_block_allocate(sb, goal, 0, &len);
467		if (start >= goal) {
468			res = -ENOSPC;
469			goto out;
470		}
471	}
472
473	if (zeroout) {
474		res = sb_issue_zeroout(sb, start, len, GFP_NOFS);
475		if (res)
476			goto out;
477	}
478
479	hfs_dbg("ino %lu, start %u, len %u\n", inode->i_ino, start, len);
480
481	if (hip->alloc_blocks <= hip->first_blocks) {
482		if (!hip->first_blocks) {
483			hfs_dbg("first_extent: start %u, len %u\n",
484				start, len);
485			/* no extents yet */
486			hip->first_extents[0].start_block = cpu_to_be32(start);
487			hip->first_extents[0].block_count = cpu_to_be32(len);
488			res = 0;
489		} else {
490			/* try to append to extents in inode */
491			res = hfsplus_add_extent(hip->first_extents,
492						 hip->alloc_blocks,
493						 start, len);
494			if (res == -ENOSPC)
495				goto insert_extent;
496		}
497		if (!res) {
498			hfsplus_dump_extent(hip->first_extents);
499			hip->first_blocks += len;
500		}
501	} else {
502		res = hfsplus_add_extent(hip->cached_extents,
503					 hip->alloc_blocks - hip->cached_start,
504					 start, len);
505		if (!res) {
506			hfsplus_dump_extent(hip->cached_extents);
507			hip->extent_state |= HFSPLUS_EXT_DIRTY;
508			hip->cached_blocks += len;
509		} else if (res == -ENOSPC)
510			goto insert_extent;
511	}
512out:
513	if (!res) {
514		hip->alloc_blocks += len;
515		mutex_unlock(&hip->extents_lock);
516		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
517		return 0;
518	}
519	mutex_unlock(&hip->extents_lock);
520	return res;
521
522insert_extent:
523	hfs_dbg("insert new extent\n");
524	res = hfsplus_ext_write_extent_locked(inode);
525	if (res)
526		goto out;
527
528	memset(hip->cached_extents, 0, sizeof(hfsplus_extent_rec));
529	hip->cached_extents[0].start_block = cpu_to_be32(start);
530	hip->cached_extents[0].block_count = cpu_to_be32(len);
531	hfsplus_dump_extent(hip->cached_extents);
532	hip->extent_state |= HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW;
533	hip->cached_start = hip->alloc_blocks;
534	hip->cached_blocks = len;
535
536	res = 0;
537	goto out;
538}
539
540void hfsplus_file_truncate(struct inode *inode)
541{
542	struct super_block *sb = inode->i_sb;
543	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
544	struct hfs_find_data fd;
545	u32 alloc_cnt, blk_cnt, start;
546	int res;
547
548	hfs_dbg("ino %lu, phys_size %llu -> i_size %llu\n",
549		inode->i_ino, (long long)hip->phys_size, inode->i_size);
550
551	if (inode->i_size > hip->phys_size) {
552		struct address_space *mapping = inode->i_mapping;
553		struct folio *folio;
554		void *fsdata = NULL;
555		loff_t size = inode->i_size;
556
557		res = hfsplus_write_begin(NULL, mapping, size, 0,
558					  &folio, &fsdata);
559		if (res)
560			return;
561		res = generic_write_end(NULL, mapping, size, 0, 0,
562					folio, fsdata);
563		if (res < 0)
564			return;
565		mark_inode_dirty(inode);
566		return;
567	} else if (inode->i_size == hip->phys_size)
568		return;
569
570	blk_cnt = (inode->i_size + HFSPLUS_SB(sb)->alloc_blksz - 1) >>
571			HFSPLUS_SB(sb)->alloc_blksz_shift;
572
573	mutex_lock(&hip->extents_lock);
574
575	alloc_cnt = hip->alloc_blocks;
576	if (blk_cnt == alloc_cnt)
577		goto out_unlock;
578
579	res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
580	if (res) {
581		mutex_unlock(&hip->extents_lock);
582		/* XXX: We lack error handling of hfsplus_file_truncate() */
583		return;
584	}
585	while (1) {
586		if (alloc_cnt == hip->first_blocks) {
587			mutex_unlock(&fd.tree->tree_lock);
588			hfsplus_free_extents(sb, hip->first_extents,
589					     alloc_cnt, alloc_cnt - blk_cnt);
590			hfsplus_dump_extent(hip->first_extents);
591			hip->first_blocks = blk_cnt;
592			mutex_lock_nested(&fd.tree->tree_lock,
593				hfsplus_btree_lock_class(fd.tree));
594			break;
595		}
596		res = __hfsplus_ext_cache_extent(&fd, inode, alloc_cnt);
597		if (res)
598			break;
599
600		start = hip->cached_start;
601		if (blk_cnt <= start)
602			hfs_brec_remove(&fd);
603		mutex_unlock(&fd.tree->tree_lock);
604		hfsplus_free_extents(sb, hip->cached_extents,
605				     alloc_cnt - start, alloc_cnt - blk_cnt);
606		hfsplus_dump_extent(hip->cached_extents);
607		mutex_lock_nested(&fd.tree->tree_lock,
608				hfsplus_btree_lock_class(fd.tree));
609		if (blk_cnt > start) {
610			hip->extent_state |= HFSPLUS_EXT_DIRTY;
611			break;
612		}
613		alloc_cnt = start;
614		hip->cached_start = hip->cached_blocks = 0;
615		hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
616	}
617	hfs_find_exit(&fd);
618
619	hip->alloc_blocks = blk_cnt;
620out_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}