orphan.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * This file is part of UBIFS.
  4 *
  5 * Copyright (C) 2006-2008 Nokia Corporation.
  6 *
  7 * Author: Adrian Hunter
  8 */
  9
 10#include "ubifs.h"
 11
 12/*
 13 * An orphan is an inode number whose inode node has been committed to the index
 14 * with a link count of zero. That happens when an open file is deleted
 15 * (unlinked) and then a commit is run. In the normal course of events the inode
 16 * would be deleted when the file is closed. However in the case of an unclean
 17 * unmount, orphans need to be accounted for. After an unclean unmount, the
 18 * orphans' inodes must be deleted which means either scanning the entire index
 19 * looking for them, or keeping a list on flash somewhere. This unit implements
 20 * the latter approach.
 21 *
 22 * The orphan area is a fixed number of LEBs situated between the LPT area and
 23 * the main area. The number of orphan area LEBs is specified when the file
 24 * system is created. The minimum number is 1. The size of the orphan area
 25 * should be so that it can hold the maximum number of orphans that are expected
 26 * to ever exist at one time.
 27 *
 28 * The number of orphans that can fit in a LEB is:
 29 *
 30 *         (c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64)
 31 *
 32 * For example: a 15872 byte LEB can fit 1980 orphans so 1 LEB may be enough.
 33 *
 34 * Orphans are accumulated in a rb-tree. When an inode's link count drops to
 35 * zero, the inode number is added to the rb-tree. It is removed from the tree
 36 * when the inode is deleted.  Any new orphans that are in the orphan tree when
 37 * the commit is run, are written to the orphan area in 1 or more orphan nodes.
 38 * If the orphan area is full, it is consolidated to make space.  There is
 39 * always enough space because validation prevents the user from creating more
 40 * than the maximum number of orphans allowed.
 41 */
 42
 43static int dbg_check_orphans(struct ubifs_info *c);
 44
 45/**
 46 * ubifs_add_orphan - add an orphan.
 47 * @c: UBIFS file-system description object
 48 * @inum: orphan inode number
 49 *
 50 * Add an orphan. This function is called when an inodes link count drops to
 51 * zero.
 52 */
 53int ubifs_add_orphan(struct ubifs_info *c, ino_t inum)
 54{
 55	struct ubifs_orphan *orphan, *o;
 56	struct rb_node **p, *parent = NULL;
 57
 58	orphan = kzalloc(sizeof(struct ubifs_orphan), GFP_NOFS);
 59	if (!orphan)
 60		return -ENOMEM;
 61	orphan->inum = inum;
 62	orphan->new = 1;
 63
 64	spin_lock(&c->orphan_lock);
 65	if (c->tot_orphans >= c->max_orphans) {
 66		spin_unlock(&c->orphan_lock);
 67		kfree(orphan);
 68		return -ENFILE;
 69	}
 70	p = &c->orph_tree.rb_node;
 71	while (*p) {
 72		parent = *p;
 73		o = rb_entry(parent, struct ubifs_orphan, rb);
 74		if (inum < o->inum)
 75			p = &(*p)->rb_left;
 76		else if (inum > o->inum)
 77			p = &(*p)->rb_right;
 78		else {
 79			ubifs_err(c, "ino %lu orphaned twice", (unsigned long)inum);
 80			spin_unlock(&c->orphan_lock);
 81			kfree(orphan);
 82			return -EINVAL;
 83		}
 84	}
 85	c->tot_orphans += 1;
 86	c->new_orphans += 1;
 87	rb_link_node(&orphan->rb, parent, p);
 88	rb_insert_color(&orphan->rb, &c->orph_tree);
 89	list_add_tail(&orphan->list, &c->orph_list);
 90	list_add_tail(&orphan->new_list, &c->orph_new);
 91
 92	spin_unlock(&c->orphan_lock);
 93	dbg_gen("ino %lu", (unsigned long)inum);
 94	return 0;
 95}
 96
 97static struct ubifs_orphan *lookup_orphan(struct ubifs_info *c, ino_t inum)
 98{
 99	struct ubifs_orphan *o;
100	struct rb_node *p;
101
102	p = c->orph_tree.rb_node;
103	while (p) {
104		o = rb_entry(p, struct ubifs_orphan, rb);
105		if (inum < o->inum)
106			p = p->rb_left;
107		else if (inum > o->inum)
108			p = p->rb_right;
109		else {
110			return o;
111		}
112	}
113	return NULL;
114}
115
116static void __orphan_drop(struct ubifs_info *c, struct ubifs_orphan *o)
117{
118	rb_erase(&o->rb, &c->orph_tree);
119	list_del(&o->list);
120	c->tot_orphans -= 1;
121
122	if (o->new) {
123		list_del(&o->new_list);
124		c->new_orphans -= 1;
125	}
126
127	kfree(o);
128}
129
130static void orphan_delete(struct ubifs_info *c, struct ubifs_orphan *orph)
131{
132	if (orph->del) {
133		dbg_gen("deleted twice ino %lu", (unsigned long)orph->inum);
134		return;
135	}
136
137	if (orph->cmt) {
138		orph->del = 1;
139		rb_erase(&orph->rb, &c->orph_tree);
140		orph->dnext = c->orph_dnext;
141		c->orph_dnext = orph;
142		dbg_gen("delete later ino %lu", (unsigned long)orph->inum);
143		return;
144	}
145
146	__orphan_drop(c, orph);
147}
148
149/**
150 * ubifs_delete_orphan - delete an orphan.
151 * @c: UBIFS file-system description object
152 * @inum: orphan inode number
153 *
154 * Delete an orphan. This function is called when an inode is deleted.
155 */
156void ubifs_delete_orphan(struct ubifs_info *c, ino_t inum)
157{
158	struct ubifs_orphan *orph;
159
160	spin_lock(&c->orphan_lock);
161
162	orph = lookup_orphan(c, inum);
163	if (!orph) {
164		spin_unlock(&c->orphan_lock);
165		ubifs_err(c, "missing orphan ino %lu", (unsigned long)inum);
166		dump_stack();
167
168		return;
169	}
170
171	orphan_delete(c, orph);
172
173	spin_unlock(&c->orphan_lock);
174}
175
176/**
177 * ubifs_orphan_start_commit - start commit of orphans.
178 * @c: UBIFS file-system description object
179 *
180 * Start commit of orphans.
181 */
182int ubifs_orphan_start_commit(struct ubifs_info *c)
183{
184	struct ubifs_orphan *orphan, **last;
185
186	spin_lock(&c->orphan_lock);
187	last = &c->orph_cnext;
188	list_for_each_entry(orphan, &c->orph_new, new_list) {
189		ubifs_assert(c, orphan->new);
190		ubifs_assert(c, !orphan->cmt);
191		orphan->new = 0;
192		orphan->cmt = 1;
193		*last = orphan;
194		last = &orphan->cnext;
195	}
196	*last = NULL;
197	c->cmt_orphans = c->new_orphans;
198	c->new_orphans = 0;
199	dbg_cmt("%d orphans to commit", c->cmt_orphans);
200	INIT_LIST_HEAD(&c->orph_new);
201	if (c->tot_orphans == 0)
202		c->no_orphs = 1;
203	else
204		c->no_orphs = 0;
205	spin_unlock(&c->orphan_lock);
206	return 0;
207}
208
209/**
210 * avail_orphs - calculate available space.
211 * @c: UBIFS file-system description object
212 *
213 * This function returns the number of orphans that can be written in the
214 * available space.
215 */
216static int avail_orphs(struct ubifs_info *c)
217{
218	int avail_lebs, avail, gap;
219
220	avail_lebs = c->orph_lebs - (c->ohead_lnum - c->orph_first) - 1;
221	avail = avail_lebs *
222	       ((c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64));
223	gap = c->leb_size - c->ohead_offs;
224	if (gap >= UBIFS_ORPH_NODE_SZ + sizeof(__le64))
225		avail += (gap - UBIFS_ORPH_NODE_SZ) / sizeof(__le64);
226	return avail;
227}
228
229/**
230 * tot_avail_orphs - calculate total space.
231 * @c: UBIFS file-system description object
232 *
233 * This function returns the number of orphans that can be written in half
234 * the total space. That leaves half the space for adding new orphans.
235 */
236static int tot_avail_orphs(struct ubifs_info *c)
237{
238	int avail_lebs, avail;
239
240	avail_lebs = c->orph_lebs;
241	avail = avail_lebs *
242	       ((c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64));
243	return avail / 2;
244}
245
246/**
247 * do_write_orph_node - write a node to the orphan head.
248 * @c: UBIFS file-system description object
249 * @len: length of node
250 * @atomic: write atomically
251 *
252 * This function writes a node to the orphan head from the orphan buffer. If
253 * %atomic is not zero, then the write is done atomically. On success, %0 is
254 * returned, otherwise a negative error code is returned.
255 */
256static int do_write_orph_node(struct ubifs_info *c, int len, int atomic)
257{
258	int err = 0;
259
260	if (atomic) {
261		ubifs_assert(c, c->ohead_offs == 0);
262		ubifs_prepare_node(c, c->orph_buf, len, 1);
263		len = ALIGN(len, c->min_io_size);
264		err = ubifs_leb_change(c, c->ohead_lnum, c->orph_buf, len);
265	} else {
266		if (c->ohead_offs == 0) {
267			/* Ensure LEB has been unmapped */
268			err = ubifs_leb_unmap(c, c->ohead_lnum);
269			if (err)
270				return err;
271		}
272		err = ubifs_write_node(c, c->orph_buf, len, c->ohead_lnum,
273				       c->ohead_offs);
274	}
275	return err;
276}
277
278/**
279 * write_orph_node - write an orphan node.
280 * @c: UBIFS file-system description object
281 * @atomic: write atomically
282 *
283 * This function builds an orphan node from the cnext list and writes it to the
284 * orphan head. On success, %0 is returned, otherwise a negative error code
285 * is returned.
286 */
287static int write_orph_node(struct ubifs_info *c, int atomic)
288{
289	struct ubifs_orphan *orphan, *cnext;
290	struct ubifs_orph_node *orph;
291	int gap, err, len, cnt, i;
292
293	ubifs_assert(c, c->cmt_orphans > 0);
294	gap = c->leb_size - c->ohead_offs;
295	if (gap < UBIFS_ORPH_NODE_SZ + sizeof(__le64)) {
296		c->ohead_lnum += 1;
297		c->ohead_offs = 0;
298		gap = c->leb_size;
299		if (c->ohead_lnum > c->orph_last) {
300			/*
301			 * We limit the number of orphans so that this should
302			 * never happen.
303			 */
304			ubifs_err(c, "out of space in orphan area");
305			return -EINVAL;
306		}
307	}
308	cnt = (gap - UBIFS_ORPH_NODE_SZ) / sizeof(__le64);
309	if (cnt > c->cmt_orphans)
310		cnt = c->cmt_orphans;
311	len = UBIFS_ORPH_NODE_SZ + cnt * sizeof(__le64);
312	ubifs_assert(c, c->orph_buf);
313	orph = c->orph_buf;
314	orph->ch.node_type = UBIFS_ORPH_NODE;
315	spin_lock(&c->orphan_lock);
316	cnext = c->orph_cnext;
317	for (i = 0; i < cnt; i++) {
318		orphan = cnext;
319		ubifs_assert(c, orphan->cmt);
320		orph->inos[i] = cpu_to_le64(orphan->inum);
321		orphan->cmt = 0;
322		cnext = orphan->cnext;
323		orphan->cnext = NULL;
324	}
325	c->orph_cnext = cnext;
326	c->cmt_orphans -= cnt;
327	spin_unlock(&c->orphan_lock);
328	if (c->cmt_orphans)
329		orph->cmt_no = cpu_to_le64(c->cmt_no);
330	else
331		/* Mark the last node of the commit */
332		orph->cmt_no = cpu_to_le64((c->cmt_no) | (1ULL << 63));
333	ubifs_assert(c, c->ohead_offs + len <= c->leb_size);
334	ubifs_assert(c, c->ohead_lnum >= c->orph_first);
335	ubifs_assert(c, c->ohead_lnum <= c->orph_last);
336	err = do_write_orph_node(c, len, atomic);
337	c->ohead_offs += ALIGN(len, c->min_io_size);
338	c->ohead_offs = ALIGN(c->ohead_offs, 8);
339	return err;
340}
341
342/**
343 * write_orph_nodes - write orphan nodes until there are no more to commit.
344 * @c: UBIFS file-system description object
345 * @atomic: write atomically
346 *
347 * This function writes orphan nodes for all the orphans to commit. On success,
348 * %0 is returned, otherwise a negative error code is returned.
349 */
350static int write_orph_nodes(struct ubifs_info *c, int atomic)
351{
352	int err;
353
354	while (c->cmt_orphans > 0) {
355		err = write_orph_node(c, atomic);
356		if (err)
357			return err;
358	}
359	if (atomic) {
360		int lnum;
361
362		/* Unmap any unused LEBs after consolidation */
363		for (lnum = c->ohead_lnum + 1; lnum <= c->orph_last; lnum++) {
364			err = ubifs_leb_unmap(c, lnum);
365			if (err)
366				return err;
367		}
368	}
369	return 0;
370}
371
372/**
373 * consolidate - consolidate the orphan area.
374 * @c: UBIFS file-system description object
375 *
376 * This function enables consolidation by putting all the orphans into the list
377 * to commit. The list is in the order that the orphans were added, and the
378 * LEBs are written atomically in order, so at no time can orphans be lost by
379 * an unclean unmount.
380 *
381 * This function returns %0 on success and a negative error code on failure.
382 */
383static int consolidate(struct ubifs_info *c)
384{
385	int tot_avail = tot_avail_orphs(c), err = 0;
386
387	spin_lock(&c->orphan_lock);
388	dbg_cmt("there is space for %d orphans and there are %d",
389		tot_avail, c->tot_orphans);
390	if (c->tot_orphans - c->new_orphans <= tot_avail) {
391		struct ubifs_orphan *orphan, **last;
392		int cnt = 0;
393
394		/* Change the cnext list to include all non-new orphans */
395		last = &c->orph_cnext;
396		list_for_each_entry(orphan, &c->orph_list, list) {
397			if (orphan->new)
398				continue;
399			orphan->cmt = 1;
400			*last = orphan;
401			last = &orphan->cnext;
402			cnt += 1;
403		}
404		*last = NULL;
405		ubifs_assert(c, cnt == c->tot_orphans - c->new_orphans);
406		c->cmt_orphans = cnt;
407		c->ohead_lnum = c->orph_first;
408		c->ohead_offs = 0;
409	} else {
410		/*
411		 * We limit the number of orphans so that this should
412		 * never happen.
413		 */
414		ubifs_err(c, "out of space in orphan area");
415		err = -EINVAL;
416	}
417	spin_unlock(&c->orphan_lock);
418	return err;
419}
420
421/**
422 * commit_orphans - commit orphans.
423 * @c: UBIFS file-system description object
424 *
425 * This function commits orphans to flash. On success, %0 is returned,
426 * otherwise a negative error code is returned.
427 */
428static int commit_orphans(struct ubifs_info *c)
429{
430	int avail, atomic = 0, err;
431
432	ubifs_assert(c, c->cmt_orphans > 0);
433	avail = avail_orphs(c);
434	if (avail < c->cmt_orphans) {
435		/* Not enough space to write new orphans, so consolidate */
436		err = consolidate(c);
437		if (err)
438			return err;
439		atomic = 1;
440	}
441	err = write_orph_nodes(c, atomic);
442	return err;
443}
444
445/**
446 * erase_deleted - erase the orphans marked for deletion.
447 * @c: UBIFS file-system description object
448 *
449 * During commit, the orphans being committed cannot be deleted, so they are
450 * marked for deletion and deleted by this function. Also, the recovery
451 * adds killed orphans to the deletion list, and therefore they are deleted
452 * here too.
453 */
454static void erase_deleted(struct ubifs_info *c)
455{
456	struct ubifs_orphan *orphan, *dnext;
457
458	spin_lock(&c->orphan_lock);
459	dnext = c->orph_dnext;
460	while (dnext) {
461		orphan = dnext;
462		dnext = orphan->dnext;
463		ubifs_assert(c, !orphan->new);
464		ubifs_assert(c, orphan->del);
465		list_del(&orphan->list);
466		c->tot_orphans -= 1;
467		dbg_gen("deleting orphan ino %lu", (unsigned long)orphan->inum);
468		kfree(orphan);
469	}
470	c->orph_dnext = NULL;
471	spin_unlock(&c->orphan_lock);
472}
473
474/**
475 * ubifs_orphan_end_commit - end commit of orphans.
476 * @c: UBIFS file-system description object
477 *
478 * End commit of orphans.
479 */
480int ubifs_orphan_end_commit(struct ubifs_info *c)
481{
482	int err;
483
484	if (c->cmt_orphans != 0) {
485		err = commit_orphans(c);
486		if (err)
487			return err;
488	}
489	erase_deleted(c);
490	err = dbg_check_orphans(c);
491	return err;
492}
493
494/**
495 * ubifs_clear_orphans - erase all LEBs used for orphans.
496 * @c: UBIFS file-system description object
497 *
498 * If recovery is not required, then the orphans from the previous session
499 * are not needed. This function locates the LEBs used to record
500 * orphans, and un-maps them.
501 */
502int ubifs_clear_orphans(struct ubifs_info *c)
503{
504	int lnum, err;
505
506	for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
507		err = ubifs_leb_unmap(c, lnum);
508		if (err)
509			return err;
510	}
511	c->ohead_lnum = c->orph_first;
512	c->ohead_offs = 0;
513	return 0;
514}
515
516/**
517 * do_kill_orphans - remove orphan inodes from the index.
518 * @c: UBIFS file-system description object
519 * @sleb: scanned LEB
520 * @last_cmt_no: cmt_no of last orphan node read is passed and returned here
521 * @outofdate: whether the LEB is out of date is returned here
522 * @last_flagged: whether the end orphan node is encountered
523 *
524 * This function is a helper to the 'kill_orphans()' function. It goes through
525 * every orphan node in a LEB and for every inode number recorded, removes
526 * all keys for that inode from the TNC.
527 */
528static int do_kill_orphans(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
529			   unsigned long long *last_cmt_no, int *outofdate,
530			   int *last_flagged)
531{
532	struct ubifs_scan_node *snod;
533	struct ubifs_orph_node *orph;
534	struct ubifs_ino_node *ino = NULL;
535	unsigned long long cmt_no;
536	ino_t inum;
537	int i, n, err, first = 1;
538
539	ino = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
540	if (!ino)
541		return -ENOMEM;
542
543	list_for_each_entry(snod, &sleb->nodes, list) {
544		if (snod->type != UBIFS_ORPH_NODE) {
545			ubifs_err(c, "invalid node type %d in orphan area at %d:%d",
546				  snod->type, sleb->lnum, snod->offs);
547			ubifs_dump_node(c, snod->node,
548					c->leb_size - snod->offs);
549			err = -EINVAL;
550			goto out_free;
551		}
552
553		orph = snod->node;
554
555		/* Check commit number */
556		cmt_no = le64_to_cpu(orph->cmt_no) & LLONG_MAX;
557		/*
558		 * The commit number on the master node may be less, because
559		 * of a failed commit. If there are several failed commits in a
560		 * row, the commit number written on orphan nodes will continue
561		 * to increase (because the commit number is adjusted here) even
562		 * though the commit number on the master node stays the same
563		 * because the master node has not been re-written.
564		 */
565		if (cmt_no > c->cmt_no)
566			c->cmt_no = cmt_no;
567		if (cmt_no < *last_cmt_no && *last_flagged) {
568			/*
569			 * The last orphan node had a higher commit number and
570			 * was flagged as the last written for that commit
571			 * number. That makes this orphan node, out of date.
572			 */
573			if (!first) {
574				ubifs_err(c, "out of order commit number %llu in orphan node at %d:%d",
575					  cmt_no, sleb->lnum, snod->offs);
576				ubifs_dump_node(c, snod->node,
577						c->leb_size - snod->offs);
578				err = -EINVAL;
579				goto out_free;
580			}
581			dbg_rcvry("out of date LEB %d", sleb->lnum);
582			*outofdate = 1;
583			err = 0;
584			goto out_free;
585		}
586
587		if (first)
588			first = 0;
589
590		n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
591		for (i = 0; i < n; i++) {
592			union ubifs_key key;
593
594			inum = le64_to_cpu(orph->inos[i]);
595
596			ino_key_init(c, &key, inum);
597			err = ubifs_tnc_lookup(c, &key, ino);
598			if (err && err != -ENOENT)
599				goto out_free;
600
601			/*
602			 * Check whether an inode can really get deleted.
603			 * linkat() with O_TMPFILE allows rebirth of an inode.
604			 */
605			if (err == 0 && ino->nlink == 0) {
606				dbg_rcvry("deleting orphaned inode %lu",
607					  (unsigned long)inum);
608
609				err = ubifs_tnc_remove_ino(c, inum);
610				if (err)
611					goto out_ro;
612			}
613		}
614
615		*last_cmt_no = cmt_no;
616		if (le64_to_cpu(orph->cmt_no) & (1ULL << 63)) {
617			dbg_rcvry("last orph node for commit %llu at %d:%d",
618				  cmt_no, sleb->lnum, snod->offs);
619			*last_flagged = 1;
620		} else
621			*last_flagged = 0;
622	}
623
624	err = 0;
625out_free:
626	kfree(ino);
627	return err;
628
629out_ro:
630	ubifs_ro_mode(c, err);
631	kfree(ino);
632	return err;
633}
634
635/**
636 * kill_orphans - remove all orphan inodes from the index.
637 * @c: UBIFS file-system description object
638 *
639 * If recovery is required, then orphan inodes recorded during the previous
640 * session (which ended with an unclean unmount) must be deleted from the index.
641 * This is done by updating the TNC, but since the index is not updated until
642 * the next commit, the LEBs where the orphan information is recorded are not
643 * erased until the next commit.
644 */
645static int kill_orphans(struct ubifs_info *c)
646{
647	unsigned long long last_cmt_no = 0;
648	int lnum, err = 0, outofdate = 0, last_flagged = 0;
649
650	c->ohead_lnum = c->orph_first;
651	c->ohead_offs = 0;
652	/* Check no-orphans flag and skip this if no orphans */
653	if (c->no_orphs) {
654		dbg_rcvry("no orphans");
655		return 0;
656	}
657	/*
658	 * Orph nodes always start at c->orph_first and are written to each
659	 * successive LEB in turn. Generally unused LEBs will have been unmapped
660	 * but may contain out of date orphan nodes if the unmap didn't go
661	 * through. In addition, the last orphan node written for each commit is
662	 * marked (top bit of orph->cmt_no is set to 1). It is possible that
663	 * there are orphan nodes from the next commit (i.e. the commit did not
664	 * complete successfully). In that case, no orphans will have been lost
665	 * due to the way that orphans are written, and any orphans added will
666	 * be valid orphans anyway and so can be deleted.
667	 */
668	for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
669		struct ubifs_scan_leb *sleb;
670
671		dbg_rcvry("LEB %d", lnum);
672		sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
673		if (IS_ERR(sleb)) {
674			if (PTR_ERR(sleb) == -EUCLEAN)
675				sleb = ubifs_recover_leb(c, lnum, 0,
676							 c->sbuf, -1);
677			if (IS_ERR(sleb)) {
678				err = PTR_ERR(sleb);
679				break;
680			}
681		}
682		err = do_kill_orphans(c, sleb, &last_cmt_no, &outofdate,
683				      &last_flagged);
684		if (err || outofdate) {
685			ubifs_scan_destroy(sleb);
686			break;
687		}
688		if (sleb->endpt) {
689			c->ohead_lnum = lnum;
690			c->ohead_offs = sleb->endpt;
691		}
692		ubifs_scan_destroy(sleb);
693	}
694	return err;
695}
696
697/**
698 * ubifs_mount_orphans - delete orphan inodes and erase LEBs that recorded them.
699 * @c: UBIFS file-system description object
700 * @unclean: indicates recovery from unclean unmount
701 * @read_only: indicates read only mount
702 *
703 * This function is called when mounting to erase orphans from the previous
704 * session. If UBIFS was not unmounted cleanly, then the inodes recorded as
705 * orphans are deleted.
706 */
707int ubifs_mount_orphans(struct ubifs_info *c, int unclean, int read_only)
708{
709	int err = 0;
710
711	c->max_orphans = tot_avail_orphs(c);
712
713	if (!read_only) {
714		c->orph_buf = vmalloc(c->leb_size);
715		if (!c->orph_buf)
716			return -ENOMEM;
717	}
718
719	if (unclean)
720		err = kill_orphans(c);
721	else if (!read_only)
722		err = ubifs_clear_orphans(c);
723
724	return err;
725}
726
727/*
728 * Everything below is related to debugging.
729 */
730
731struct check_orphan {
732	struct rb_node rb;
733	ino_t inum;
734};
735
736struct check_info {
737	unsigned long last_ino;
738	unsigned long tot_inos;
739	unsigned long missing;
740	unsigned long long leaf_cnt;
741	struct ubifs_ino_node *node;
742	struct rb_root root;
743};
744
745static bool dbg_find_orphan(struct ubifs_info *c, ino_t inum)
746{
747	bool found = false;
748
749	spin_lock(&c->orphan_lock);
750	found = !!lookup_orphan(c, inum);
751	spin_unlock(&c->orphan_lock);
752
753	return found;
754}
755
756static int dbg_ins_check_orphan(struct rb_root *root, ino_t inum)
757{
758	struct check_orphan *orphan, *o;
759	struct rb_node **p, *parent = NULL;
760
761	orphan = kzalloc(sizeof(struct check_orphan), GFP_NOFS);
762	if (!orphan)
763		return -ENOMEM;
764	orphan->inum = inum;
765
766	p = &root->rb_node;
767	while (*p) {
768		parent = *p;
769		o = rb_entry(parent, struct check_orphan, rb);
770		if (inum < o->inum)
771			p = &(*p)->rb_left;
772		else if (inum > o->inum)
773			p = &(*p)->rb_right;
774		else {
775			kfree(orphan);
776			return 0;
777		}
778	}
779	rb_link_node(&orphan->rb, parent, p);
780	rb_insert_color(&orphan->rb, root);
781	return 0;
782}
783
784static int dbg_find_check_orphan(struct rb_root *root, ino_t inum)
785{
786	struct check_orphan *o;
787	struct rb_node *p;
788
789	p = root->rb_node;
790	while (p) {
791		o = rb_entry(p, struct check_orphan, rb);
792		if (inum < o->inum)
793			p = p->rb_left;
794		else if (inum > o->inum)
795			p = p->rb_right;
796		else
797			return 1;
798	}
799	return 0;
800}
801
802static void dbg_free_check_tree(struct rb_root *root)
803{
804	struct check_orphan *o, *n;
805
806	rbtree_postorder_for_each_entry_safe(o, n, root, rb)
807		kfree(o);
808}
809
810static int dbg_orphan_check(struct ubifs_info *c, struct ubifs_zbranch *zbr,
811			    void *priv)
812{
813	struct check_info *ci = priv;
814	ino_t inum;
815	int err;
816
817	inum = key_inum(c, &zbr->key);
818	if (inum != ci->last_ino) {
819		/*
820		 * Lowest node type is the inode node or xattr entry(when
821		 * selinux/encryption is enabled), so it comes first
822		 */
823		if (key_type(c, &zbr->key) != UBIFS_INO_KEY &&
824		    key_type(c, &zbr->key) != UBIFS_XENT_KEY)
825			ubifs_err(c, "found orphan node ino %lu, type %d",
826				  (unsigned long)inum, key_type(c, &zbr->key));
827		ci->last_ino = inum;
828		ci->tot_inos += 1;
829		err = ubifs_tnc_read_node(c, zbr, ci->node);
830		if (err) {
831			ubifs_err(c, "node read failed, error %d", err);
832			return err;
833		}
834		if (ci->node->nlink == 0)
835			/* Must be recorded as an orphan */
836			if (!dbg_find_check_orphan(&ci->root, inum) &&
837			    !dbg_find_orphan(c, inum)) {
838				ubifs_err(c, "missing orphan, ino %lu",
839					  (unsigned long)inum);
840				ci->missing += 1;
841			}
842	}
843	ci->leaf_cnt += 1;
844	return 0;
845}
846
847static int dbg_read_orphans(struct check_info *ci, struct ubifs_scan_leb *sleb)
848{
849	struct ubifs_scan_node *snod;
850	struct ubifs_orph_node *orph;
851	ino_t inum;
852	int i, n, err;
853
854	list_for_each_entry(snod, &sleb->nodes, list) {
855		cond_resched();
856		if (snod->type != UBIFS_ORPH_NODE)
857			continue;
858		orph = snod->node;
859		n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
860		for (i = 0; i < n; i++) {
861			inum = le64_to_cpu(orph->inos[i]);
862			err = dbg_ins_check_orphan(&ci->root, inum);
863			if (err)
864				return err;
865		}
866	}
867	return 0;
868}
869
870static int dbg_scan_orphans(struct ubifs_info *c, struct check_info *ci)
871{
872	int lnum, err = 0;
873	void *buf;
874
875	/* Check no-orphans flag and skip this if no orphans */
876	if (c->no_orphs)
877		return 0;
878
879	buf = __vmalloc(c->leb_size, GFP_NOFS);
880	if (!buf) {
881		ubifs_err(c, "cannot allocate memory to check orphans");
882		return 0;
883	}
884
885	for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
886		struct ubifs_scan_leb *sleb;
887
888		sleb = ubifs_scan(c, lnum, 0, buf, 0);
889		if (IS_ERR(sleb)) {
890			err = PTR_ERR(sleb);
891			break;
892		}
893
894		err = dbg_read_orphans(ci, sleb);
895		ubifs_scan_destroy(sleb);
896		if (err)
897			break;
898	}
899
900	vfree(buf);
901	return err;
902}
903
904static int dbg_check_orphans(struct ubifs_info *c)
905{
906	struct check_info ci;
907	int err;
908
909	if (!dbg_is_chk_orph(c))
910		return 0;
911
912	ci.last_ino = 0;
913	ci.tot_inos = 0;
914	ci.missing  = 0;
915	ci.leaf_cnt = 0;
916	ci.root = RB_ROOT;
917	ci.node = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
918	if (!ci.node) {
919		ubifs_err(c, "out of memory");
920		return -ENOMEM;
921	}
922
923	err = dbg_scan_orphans(c, &ci);
924	if (err)
925		goto out;
926
927	err = dbg_walk_index(c, &dbg_orphan_check, NULL, &ci);
928	if (err) {
929		ubifs_err(c, "cannot scan TNC, error %d", err);
930		goto out;
931	}
932
933	if (ci.missing) {
934		ubifs_err(c, "%lu missing orphan(s)", ci.missing);
935		err = -EINVAL;
936		goto out;
937	}
938
939	dbg_cmt("last inode number is %lu", ci.last_ino);
940	dbg_cmt("total number of inodes is %lu", ci.tot_inos);
941	dbg_cmt("total number of leaf nodes is %llu", ci.leaf_cnt);
942
943out:
944	dbg_free_check_tree(&ci.root);
945	kfree(ci.node);
946	return err;
947}