xref: /openbmc/u-boot/fs/ubifs/orphan.c (revision d9b23e26)
1  /*
2   * This file is part of UBIFS.
3   *
4   * Copyright (C) 2006-2008 Nokia Corporation.
5   *
6   * SPDX-License-Identifier:	GPL-2.0+
7   *
8   * Author: Adrian Hunter
9   */
10  
11  #include <linux/err.h>
12  #include "ubifs.h"
13  
14  /*
15   * An orphan is an inode number whose inode node has been committed to the index
16   * with a link count of zero. That happens when an open file is deleted
17   * (unlinked) and then a commit is run. In the normal course of events the inode
18   * would be deleted when the file is closed. However in the case of an unclean
19   * unmount, orphans need to be accounted for. After an unclean unmount, the
20   * orphans' inodes must be deleted which means either scanning the entire index
21   * looking for them, or keeping a list on flash somewhere. This unit implements
22   * the latter approach.
23   *
24   * The orphan area is a fixed number of LEBs situated between the LPT area and
25   * the main area. The number of orphan area LEBs is specified when the file
26   * system is created. The minimum number is 1. The size of the orphan area
27   * should be so that it can hold the maximum number of orphans that are expected
28   * to ever exist at one time.
29   *
30   * The number of orphans that can fit in a LEB is:
31   *
32   *         (c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64)
33   *
34   * For example: a 15872 byte LEB can fit 1980 orphans so 1 LEB may be enough.
35   *
36   * Orphans are accumulated in a rb-tree. When an inode's link count drops to
37   * zero, the inode number is added to the rb-tree. It is removed from the tree
38   * when the inode is deleted.  Any new orphans that are in the orphan tree when
39   * the commit is run, are written to the orphan area in 1 or more orphan nodes.
40   * If the orphan area is full, it is consolidated to make space.  There is
41   * always enough space because validation prevents the user from creating more
42   * than the maximum number of orphans allowed.
43   */
44  
45  static int dbg_check_orphans(struct ubifs_info *c);
46  
47  /**
48   * ubifs_add_orphan - add an orphan.
49   * @c: UBIFS file-system description object
50   * @inum: orphan inode number
51   *
52   * Add an orphan. This function is called when an inodes link count drops to
53   * zero.
54   */
55  int ubifs_add_orphan(struct ubifs_info *c, ino_t inum)
56  {
57  	struct ubifs_orphan *orphan, *o;
58  	struct rb_node **p, *parent = NULL;
59  
60  	orphan = kzalloc(sizeof(struct ubifs_orphan), GFP_NOFS);
61  	if (!orphan)
62  		return -ENOMEM;
63  	orphan->inum = inum;
64  	orphan->new = 1;
65  
66  	spin_lock(&c->orphan_lock);
67  	if (c->tot_orphans >= c->max_orphans) {
68  		spin_unlock(&c->orphan_lock);
69  		kfree(orphan);
70  		return -ENFILE;
71  	}
72  	p = &c->orph_tree.rb_node;
73  	while (*p) {
74  		parent = *p;
75  		o = rb_entry(parent, struct ubifs_orphan, rb);
76  		if (inum < o->inum)
77  			p = &(*p)->rb_left;
78  		else if (inum > o->inum)
79  			p = &(*p)->rb_right;
80  		else {
81  			ubifs_err(c, "orphaned twice");
82  			spin_unlock(&c->orphan_lock);
83  			kfree(orphan);
84  			return 0;
85  		}
86  	}
87  	c->tot_orphans += 1;
88  	c->new_orphans += 1;
89  	rb_link_node(&orphan->rb, parent, p);
90  	rb_insert_color(&orphan->rb, &c->orph_tree);
91  	list_add_tail(&orphan->list, &c->orph_list);
92  	list_add_tail(&orphan->new_list, &c->orph_new);
93  	spin_unlock(&c->orphan_lock);
94  	dbg_gen("ino %lu", (unsigned long)inum);
95  	return 0;
96  }
97  
98  /**
99   * ubifs_delete_orphan - delete an orphan.
100   * @c: UBIFS file-system description object
101   * @inum: orphan inode number
102   *
103   * Delete an orphan. This function is called when an inode is deleted.
104   */
105  void ubifs_delete_orphan(struct ubifs_info *c, ino_t inum)
106  {
107  	struct ubifs_orphan *o;
108  	struct rb_node *p;
109  
110  	spin_lock(&c->orphan_lock);
111  	p = c->orph_tree.rb_node;
112  	while (p) {
113  		o = rb_entry(p, struct ubifs_orphan, rb);
114  		if (inum < o->inum)
115  			p = p->rb_left;
116  		else if (inum > o->inum)
117  			p = p->rb_right;
118  		else {
119  			if (o->del) {
120  				spin_unlock(&c->orphan_lock);
121  				dbg_gen("deleted twice ino %lu",
122  					(unsigned long)inum);
123  				return;
124  			}
125  			if (o->cmt) {
126  				o->del = 1;
127  				o->dnext = c->orph_dnext;
128  				c->orph_dnext = o;
129  				spin_unlock(&c->orphan_lock);
130  				dbg_gen("delete later ino %lu",
131  					(unsigned long)inum);
132  				return;
133  			}
134  			rb_erase(p, &c->orph_tree);
135  			list_del(&o->list);
136  			c->tot_orphans -= 1;
137  			if (o->new) {
138  				list_del(&o->new_list);
139  				c->new_orphans -= 1;
140  			}
141  			spin_unlock(&c->orphan_lock);
142  			kfree(o);
143  			dbg_gen("inum %lu", (unsigned long)inum);
144  			return;
145  		}
146  	}
147  	spin_unlock(&c->orphan_lock);
148  	ubifs_err(c, "missing orphan ino %lu", (unsigned long)inum);
149  	dump_stack();
150  }
151  
152  /**
153   * ubifs_orphan_start_commit - start commit of orphans.
154   * @c: UBIFS file-system description object
155   *
156   * Start commit of orphans.
157   */
158  int ubifs_orphan_start_commit(struct ubifs_info *c)
159  {
160  	struct ubifs_orphan *orphan, **last;
161  
162  	spin_lock(&c->orphan_lock);
163  	last = &c->orph_cnext;
164  	list_for_each_entry(orphan, &c->orph_new, new_list) {
165  		ubifs_assert(orphan->new);
166  		ubifs_assert(!orphan->cmt);
167  		orphan->new = 0;
168  		orphan->cmt = 1;
169  		*last = orphan;
170  		last = &orphan->cnext;
171  	}
172  	*last = NULL;
173  	c->cmt_orphans = c->new_orphans;
174  	c->new_orphans = 0;
175  	dbg_cmt("%d orphans to commit", c->cmt_orphans);
176  	INIT_LIST_HEAD(&c->orph_new);
177  	if (c->tot_orphans == 0)
178  		c->no_orphs = 1;
179  	else
180  		c->no_orphs = 0;
181  	spin_unlock(&c->orphan_lock);
182  	return 0;
183  }
184  
185  /**
186   * avail_orphs - calculate available space.
187   * @c: UBIFS file-system description object
188   *
189   * This function returns the number of orphans that can be written in the
190   * available space.
191   */
192  static int avail_orphs(struct ubifs_info *c)
193  {
194  	int avail_lebs, avail, gap;
195  
196  	avail_lebs = c->orph_lebs - (c->ohead_lnum - c->orph_first) - 1;
197  	avail = avail_lebs *
198  	       ((c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64));
199  	gap = c->leb_size - c->ohead_offs;
200  	if (gap >= UBIFS_ORPH_NODE_SZ + sizeof(__le64))
201  		avail += (gap - UBIFS_ORPH_NODE_SZ) / sizeof(__le64);
202  	return avail;
203  }
204  
205  /**
206   * tot_avail_orphs - calculate total space.
207   * @c: UBIFS file-system description object
208   *
209   * This function returns the number of orphans that can be written in half
210   * the total space. That leaves half the space for adding new orphans.
211   */
212  static int tot_avail_orphs(struct ubifs_info *c)
213  {
214  	int avail_lebs, avail;
215  
216  	avail_lebs = c->orph_lebs;
217  	avail = avail_lebs *
218  	       ((c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64));
219  	return avail / 2;
220  }
221  
222  /**
223   * do_write_orph_node - write a node to the orphan head.
224   * @c: UBIFS file-system description object
225   * @len: length of node
226   * @atomic: write atomically
227   *
228   * This function writes a node to the orphan head from the orphan buffer. If
229   * %atomic is not zero, then the write is done atomically. On success, %0 is
230   * returned, otherwise a negative error code is returned.
231   */
232  static int do_write_orph_node(struct ubifs_info *c, int len, int atomic)
233  {
234  	int err = 0;
235  
236  	if (atomic) {
237  		ubifs_assert(c->ohead_offs == 0);
238  		ubifs_prepare_node(c, c->orph_buf, len, 1);
239  		len = ALIGN(len, c->min_io_size);
240  		err = ubifs_leb_change(c, c->ohead_lnum, c->orph_buf, len);
241  	} else {
242  		if (c->ohead_offs == 0) {
243  			/* Ensure LEB has been unmapped */
244  			err = ubifs_leb_unmap(c, c->ohead_lnum);
245  			if (err)
246  				return err;
247  		}
248  		err = ubifs_write_node(c, c->orph_buf, len, c->ohead_lnum,
249  				       c->ohead_offs);
250  	}
251  	return err;
252  }
253  
254  /**
255   * write_orph_node - write an orphan node.
256   * @c: UBIFS file-system description object
257   * @atomic: write atomically
258   *
259   * This function builds an orphan node from the cnext list and writes it to the
260   * orphan head. On success, %0 is returned, otherwise a negative error code
261   * is returned.
262   */
263  static int write_orph_node(struct ubifs_info *c, int atomic)
264  {
265  	struct ubifs_orphan *orphan, *cnext;
266  	struct ubifs_orph_node *orph;
267  	int gap, err, len, cnt, i;
268  
269  	ubifs_assert(c->cmt_orphans > 0);
270  	gap = c->leb_size - c->ohead_offs;
271  	if (gap < UBIFS_ORPH_NODE_SZ + sizeof(__le64)) {
272  		c->ohead_lnum += 1;
273  		c->ohead_offs = 0;
274  		gap = c->leb_size;
275  		if (c->ohead_lnum > c->orph_last) {
276  			/*
277  			 * We limit the number of orphans so that this should
278  			 * never happen.
279  			 */
280  			ubifs_err(c, "out of space in orphan area");
281  			return -EINVAL;
282  		}
283  	}
284  	cnt = (gap - UBIFS_ORPH_NODE_SZ) / sizeof(__le64);
285  	if (cnt > c->cmt_orphans)
286  		cnt = c->cmt_orphans;
287  	len = UBIFS_ORPH_NODE_SZ + cnt * sizeof(__le64);
288  	ubifs_assert(c->orph_buf);
289  	orph = c->orph_buf;
290  	orph->ch.node_type = UBIFS_ORPH_NODE;
291  	spin_lock(&c->orphan_lock);
292  	cnext = c->orph_cnext;
293  	for (i = 0; i < cnt; i++) {
294  		orphan = cnext;
295  		ubifs_assert(orphan->cmt);
296  		orph->inos[i] = cpu_to_le64(orphan->inum);
297  		orphan->cmt = 0;
298  		cnext = orphan->cnext;
299  		orphan->cnext = NULL;
300  	}
301  	c->orph_cnext = cnext;
302  	c->cmt_orphans -= cnt;
303  	spin_unlock(&c->orphan_lock);
304  	if (c->cmt_orphans)
305  		orph->cmt_no = cpu_to_le64(c->cmt_no);
306  	else
307  		/* Mark the last node of the commit */
308  		orph->cmt_no = cpu_to_le64((c->cmt_no) | (1ULL << 63));
309  	ubifs_assert(c->ohead_offs + len <= c->leb_size);
310  	ubifs_assert(c->ohead_lnum >= c->orph_first);
311  	ubifs_assert(c->ohead_lnum <= c->orph_last);
312  	err = do_write_orph_node(c, len, atomic);
313  	c->ohead_offs += ALIGN(len, c->min_io_size);
314  	c->ohead_offs = ALIGN(c->ohead_offs, 8);
315  	return err;
316  }
317  
318  /**
319   * write_orph_nodes - write orphan nodes until there are no more to commit.
320   * @c: UBIFS file-system description object
321   * @atomic: write atomically
322   *
323   * This function writes orphan nodes for all the orphans to commit. On success,
324   * %0 is returned, otherwise a negative error code is returned.
325   */
326  static int write_orph_nodes(struct ubifs_info *c, int atomic)
327  {
328  	int err;
329  
330  	while (c->cmt_orphans > 0) {
331  		err = write_orph_node(c, atomic);
332  		if (err)
333  			return err;
334  	}
335  	if (atomic) {
336  		int lnum;
337  
338  		/* Unmap any unused LEBs after consolidation */
339  		for (lnum = c->ohead_lnum + 1; lnum <= c->orph_last; lnum++) {
340  			err = ubifs_leb_unmap(c, lnum);
341  			if (err)
342  				return err;
343  		}
344  	}
345  	return 0;
346  }
347  
348  /**
349   * consolidate - consolidate the orphan area.
350   * @c: UBIFS file-system description object
351   *
352   * This function enables consolidation by putting all the orphans into the list
353   * to commit. The list is in the order that the orphans were added, and the
354   * LEBs are written atomically in order, so at no time can orphans be lost by
355   * an unclean unmount.
356   *
357   * This function returns %0 on success and a negative error code on failure.
358   */
359  static int consolidate(struct ubifs_info *c)
360  {
361  	int tot_avail = tot_avail_orphs(c), err = 0;
362  
363  	spin_lock(&c->orphan_lock);
364  	dbg_cmt("there is space for %d orphans and there are %d",
365  		tot_avail, c->tot_orphans);
366  	if (c->tot_orphans - c->new_orphans <= tot_avail) {
367  		struct ubifs_orphan *orphan, **last;
368  		int cnt = 0;
369  
370  		/* Change the cnext list to include all non-new orphans */
371  		last = &c->orph_cnext;
372  		list_for_each_entry(orphan, &c->orph_list, list) {
373  			if (orphan->new)
374  				continue;
375  			orphan->cmt = 1;
376  			*last = orphan;
377  			last = &orphan->cnext;
378  			cnt += 1;
379  		}
380  		*last = NULL;
381  		ubifs_assert(cnt == c->tot_orphans - c->new_orphans);
382  		c->cmt_orphans = cnt;
383  		c->ohead_lnum = c->orph_first;
384  		c->ohead_offs = 0;
385  	} else {
386  		/*
387  		 * We limit the number of orphans so that this should
388  		 * never happen.
389  		 */
390  		ubifs_err(c, "out of space in orphan area");
391  		err = -EINVAL;
392  	}
393  	spin_unlock(&c->orphan_lock);
394  	return err;
395  }
396  
397  /**
398   * commit_orphans - commit orphans.
399   * @c: UBIFS file-system description object
400   *
401   * This function commits orphans to flash. On success, %0 is returned,
402   * otherwise a negative error code is returned.
403   */
404  static int commit_orphans(struct ubifs_info *c)
405  {
406  	int avail, atomic = 0, err;
407  
408  	ubifs_assert(c->cmt_orphans > 0);
409  	avail = avail_orphs(c);
410  	if (avail < c->cmt_orphans) {
411  		/* Not enough space to write new orphans, so consolidate */
412  		err = consolidate(c);
413  		if (err)
414  			return err;
415  		atomic = 1;
416  	}
417  	err = write_orph_nodes(c, atomic);
418  	return err;
419  }
420  
421  /**
422   * erase_deleted - erase the orphans marked for deletion.
423   * @c: UBIFS file-system description object
424   *
425   * During commit, the orphans being committed cannot be deleted, so they are
426   * marked for deletion and deleted by this function. Also, the recovery
427   * adds killed orphans to the deletion list, and therefore they are deleted
428   * here too.
429   */
430  static void erase_deleted(struct ubifs_info *c)
431  {
432  	struct ubifs_orphan *orphan, *dnext;
433  
434  	spin_lock(&c->orphan_lock);
435  	dnext = c->orph_dnext;
436  	while (dnext) {
437  		orphan = dnext;
438  		dnext = orphan->dnext;
439  		ubifs_assert(!orphan->new);
440  		ubifs_assert(orphan->del);
441  		rb_erase(&orphan->rb, &c->orph_tree);
442  		list_del(&orphan->list);
443  		c->tot_orphans -= 1;
444  		dbg_gen("deleting orphan ino %lu", (unsigned long)orphan->inum);
445  		kfree(orphan);
446  	}
447  	c->orph_dnext = NULL;
448  	spin_unlock(&c->orphan_lock);
449  }
450  
451  /**
452   * ubifs_orphan_end_commit - end commit of orphans.
453   * @c: UBIFS file-system description object
454   *
455   * End commit of orphans.
456   */
457  int ubifs_orphan_end_commit(struct ubifs_info *c)
458  {
459  	int err;
460  
461  	if (c->cmt_orphans != 0) {
462  		err = commit_orphans(c);
463  		if (err)
464  			return err;
465  	}
466  	erase_deleted(c);
467  	err = dbg_check_orphans(c);
468  	return err;
469  }
470  
471  /**
472   * ubifs_clear_orphans - erase all LEBs used for orphans.
473   * @c: UBIFS file-system description object
474   *
475   * If recovery is not required, then the orphans from the previous session
476   * are not needed. This function locates the LEBs used to record
477   * orphans, and un-maps them.
478   */
479  int ubifs_clear_orphans(struct ubifs_info *c)
480  {
481  	int lnum, err;
482  
483  	for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
484  		err = ubifs_leb_unmap(c, lnum);
485  		if (err)
486  			return err;
487  	}
488  	c->ohead_lnum = c->orph_first;
489  	c->ohead_offs = 0;
490  	return 0;
491  }
492  
493  /**
494   * insert_dead_orphan - insert an orphan.
495   * @c: UBIFS file-system description object
496   * @inum: orphan inode number
497   *
498   * This function is a helper to the 'do_kill_orphans()' function. The orphan
499   * must be kept until the next commit, so it is added to the rb-tree and the
500   * deletion list.
501   */
502  static int insert_dead_orphan(struct ubifs_info *c, ino_t inum)
503  {
504  	struct ubifs_orphan *orphan, *o;
505  	struct rb_node **p, *parent = NULL;
506  
507  	orphan = kzalloc(sizeof(struct ubifs_orphan), GFP_KERNEL);
508  	if (!orphan)
509  		return -ENOMEM;
510  	orphan->inum = inum;
511  
512  	p = &c->orph_tree.rb_node;
513  	while (*p) {
514  		parent = *p;
515  		o = rb_entry(parent, struct ubifs_orphan, rb);
516  		if (inum < o->inum)
517  			p = &(*p)->rb_left;
518  		else if (inum > o->inum)
519  			p = &(*p)->rb_right;
520  		else {
521  			/* Already added - no problem */
522  			kfree(orphan);
523  			return 0;
524  		}
525  	}
526  	c->tot_orphans += 1;
527  	rb_link_node(&orphan->rb, parent, p);
528  	rb_insert_color(&orphan->rb, &c->orph_tree);
529  	list_add_tail(&orphan->list, &c->orph_list);
530  	orphan->del = 1;
531  	orphan->dnext = c->orph_dnext;
532  	c->orph_dnext = orphan;
533  	dbg_mnt("ino %lu, new %d, tot %d", (unsigned long)inum,
534  		c->new_orphans, c->tot_orphans);
535  	return 0;
536  }
537  
538  /**
539   * do_kill_orphans - remove orphan inodes from the index.
540   * @c: UBIFS file-system description object
541   * @sleb: scanned LEB
542   * @last_cmt_no: cmt_no of last orphan node read is passed and returned here
543   * @outofdate: whether the LEB is out of date is returned here
544   * @last_flagged: whether the end orphan node is encountered
545   *
546   * This function is a helper to the 'kill_orphans()' function. It goes through
547   * every orphan node in a LEB and for every inode number recorded, removes
548   * all keys for that inode from the TNC.
549   */
550  static int do_kill_orphans(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
551  			   unsigned long long *last_cmt_no, int *outofdate,
552  			   int *last_flagged)
553  {
554  	struct ubifs_scan_node *snod;
555  	struct ubifs_orph_node *orph;
556  	unsigned long long cmt_no;
557  	ino_t inum;
558  	int i, n, err, first = 1;
559  
560  	list_for_each_entry(snod, &sleb->nodes, list) {
561  		if (snod->type != UBIFS_ORPH_NODE) {
562  			ubifs_err(c, "invalid node type %d in orphan area at %d:%d",
563  				  snod->type, sleb->lnum, snod->offs);
564  			ubifs_dump_node(c, snod->node);
565  			return -EINVAL;
566  		}
567  
568  		orph = snod->node;
569  
570  		/* Check commit number */
571  		cmt_no = le64_to_cpu(orph->cmt_no) & LLONG_MAX;
572  		/*
573  		 * The commit number on the master node may be less, because
574  		 * of a failed commit. If there are several failed commits in a
575  		 * row, the commit number written on orphan nodes will continue
576  		 * to increase (because the commit number is adjusted here) even
577  		 * though the commit number on the master node stays the same
578  		 * because the master node has not been re-written.
579  		 */
580  		if (cmt_no > c->cmt_no)
581  			c->cmt_no = cmt_no;
582  		if (cmt_no < *last_cmt_no && *last_flagged) {
583  			/*
584  			 * The last orphan node had a higher commit number and
585  			 * was flagged as the last written for that commit
586  			 * number. That makes this orphan node, out of date.
587  			 */
588  			if (!first) {
589  				ubifs_err(c, "out of order commit number %llu in orphan node at %d:%d",
590  					  cmt_no, sleb->lnum, snod->offs);
591  				ubifs_dump_node(c, snod->node);
592  				return -EINVAL;
593  			}
594  			dbg_rcvry("out of date LEB %d", sleb->lnum);
595  			*outofdate = 1;
596  			return 0;
597  		}
598  
599  		if (first)
600  			first = 0;
601  
602  		n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
603  		for (i = 0; i < n; i++) {
604  			inum = le64_to_cpu(orph->inos[i]);
605  			dbg_rcvry("deleting orphaned inode %lu",
606  				  (unsigned long)inum);
607  			err = ubifs_tnc_remove_ino(c, inum);
608  			if (err)
609  				return err;
610  			err = insert_dead_orphan(c, inum);
611  			if (err)
612  				return err;
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  	return 0;
625  }
626  
627  /**
628   * kill_orphans - remove all orphan inodes from the index.
629   * @c: UBIFS file-system description object
630   *
631   * If recovery is required, then orphan inodes recorded during the previous
632   * session (which ended with an unclean unmount) must be deleted from the index.
633   * This is done by updating the TNC, but since the index is not updated until
634   * the next commit, the LEBs where the orphan information is recorded are not
635   * erased until the next commit.
636   */
637  static int kill_orphans(struct ubifs_info *c)
638  {
639  	unsigned long long last_cmt_no = 0;
640  	int lnum, err = 0, outofdate = 0, last_flagged = 0;
641  
642  	c->ohead_lnum = c->orph_first;
643  	c->ohead_offs = 0;
644  	/* Check no-orphans flag and skip this if no orphans */
645  	if (c->no_orphs) {
646  		dbg_rcvry("no orphans");
647  		return 0;
648  	}
649  	/*
650  	 * Orph nodes always start at c->orph_first and are written to each
651  	 * successive LEB in turn. Generally unused LEBs will have been unmapped
652  	 * but may contain out of date orphan nodes if the unmap didn't go
653  	 * through. In addition, the last orphan node written for each commit is
654  	 * marked (top bit of orph->cmt_no is set to 1). It is possible that
655  	 * there are orphan nodes from the next commit (i.e. the commit did not
656  	 * complete successfully). In that case, no orphans will have been lost
657  	 * due to the way that orphans are written, and any orphans added will
658  	 * be valid orphans anyway and so can be deleted.
659  	 */
660  	for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
661  		struct ubifs_scan_leb *sleb;
662  
663  		dbg_rcvry("LEB %d", lnum);
664  		sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
665  		if (IS_ERR(sleb)) {
666  			if (PTR_ERR(sleb) == -EUCLEAN)
667  				sleb = ubifs_recover_leb(c, lnum, 0,
668  							 c->sbuf, -1);
669  			if (IS_ERR(sleb)) {
670  				err = PTR_ERR(sleb);
671  				break;
672  			}
673  		}
674  		err = do_kill_orphans(c, sleb, &last_cmt_no, &outofdate,
675  				      &last_flagged);
676  		if (err || outofdate) {
677  			ubifs_scan_destroy(sleb);
678  			break;
679  		}
680  		if (sleb->endpt) {
681  			c->ohead_lnum = lnum;
682  			c->ohead_offs = sleb->endpt;
683  		}
684  		ubifs_scan_destroy(sleb);
685  	}
686  	return err;
687  }
688  
689  /**
690   * ubifs_mount_orphans - delete orphan inodes and erase LEBs that recorded them.
691   * @c: UBIFS file-system description object
692   * @unclean: indicates recovery from unclean unmount
693   * @read_only: indicates read only mount
694   *
695   * This function is called when mounting to erase orphans from the previous
696   * session. If UBIFS was not unmounted cleanly, then the inodes recorded as
697   * orphans are deleted.
698   */
699  int ubifs_mount_orphans(struct ubifs_info *c, int unclean, int read_only)
700  {
701  	int err = 0;
702  
703  	c->max_orphans = tot_avail_orphs(c);
704  
705  	if (!read_only) {
706  		c->orph_buf = vmalloc(c->leb_size);
707  		if (!c->orph_buf)
708  			return -ENOMEM;
709  	}
710  
711  	if (unclean)
712  		err = kill_orphans(c);
713  	else if (!read_only)
714  		err = ubifs_clear_orphans(c);
715  
716  	return err;
717  }
718  
719  /*
720   * Everything below is related to debugging.
721   */
722  
723  struct check_orphan {
724  	struct rb_node rb;
725  	ino_t inum;
726  };
727  
728  struct check_info {
729  	unsigned long last_ino;
730  	unsigned long tot_inos;
731  	unsigned long missing;
732  	unsigned long long leaf_cnt;
733  	struct ubifs_ino_node *node;
734  	struct rb_root root;
735  };
736  
737  static int dbg_find_orphan(struct ubifs_info *c, ino_t inum)
738  {
739  	struct ubifs_orphan *o;
740  	struct rb_node *p;
741  
742  	spin_lock(&c->orphan_lock);
743  	p = c->orph_tree.rb_node;
744  	while (p) {
745  		o = rb_entry(p, struct ubifs_orphan, rb);
746  		if (inum < o->inum)
747  			p = p->rb_left;
748  		else if (inum > o->inum)
749  			p = p->rb_right;
750  		else {
751  			spin_unlock(&c->orphan_lock);
752  			return 1;
753  		}
754  	}
755  	spin_unlock(&c->orphan_lock);
756  	return 0;
757  }
758  
759  static int dbg_ins_check_orphan(struct rb_root *root, ino_t inum)
760  {
761  	struct check_orphan *orphan, *o;
762  	struct rb_node **p, *parent = NULL;
763  
764  	orphan = kzalloc(sizeof(struct check_orphan), GFP_NOFS);
765  	if (!orphan)
766  		return -ENOMEM;
767  	orphan->inum = inum;
768  
769  	p = &root->rb_node;
770  	while (*p) {
771  		parent = *p;
772  		o = rb_entry(parent, struct check_orphan, rb);
773  		if (inum < o->inum)
774  			p = &(*p)->rb_left;
775  		else if (inum > o->inum)
776  			p = &(*p)->rb_right;
777  		else {
778  			kfree(orphan);
779  			return 0;
780  		}
781  	}
782  	rb_link_node(&orphan->rb, parent, p);
783  	rb_insert_color(&orphan->rb, root);
784  	return 0;
785  }
786  
787  static int dbg_find_check_orphan(struct rb_root *root, ino_t inum)
788  {
789  	struct check_orphan *o;
790  	struct rb_node *p;
791  
792  	p = root->rb_node;
793  	while (p) {
794  		o = rb_entry(p, struct check_orphan, rb);
795  		if (inum < o->inum)
796  			p = p->rb_left;
797  		else if (inum > o->inum)
798  			p = p->rb_right;
799  		else
800  			return 1;
801  	}
802  	return 0;
803  }
804  
805  static void dbg_free_check_tree(struct rb_root *root)
806  {
807  	struct check_orphan *o, *n;
808  
809  	rbtree_postorder_for_each_entry_safe(o, n, root, rb)
810  		kfree(o);
811  }
812  
813  static int dbg_orphan_check(struct ubifs_info *c, struct ubifs_zbranch *zbr,
814  			    void *priv)
815  {
816  	struct check_info *ci = priv;
817  	ino_t inum;
818  	int err;
819  
820  	inum = key_inum(c, &zbr->key);
821  	if (inum != ci->last_ino) {
822  		/* Lowest node type is the inode node, so it comes first */
823  		if (key_type(c, &zbr->key) != UBIFS_INO_KEY)
824  			ubifs_err(c, "found orphan node ino %lu, type %d",
825  				  (unsigned long)inum, key_type(c, &zbr->key));
826  		ci->last_ino = inum;
827  		ci->tot_inos += 1;
828  		err = ubifs_tnc_read_node(c, zbr, ci->node);
829  		if (err) {
830  			ubifs_err(c, "node read failed, error %d", err);
831  			return err;
832  		}
833  		if (ci->node->nlink == 0)
834  			/* Must be recorded as an orphan */
835  			if (!dbg_find_check_orphan(&ci->root, inum) &&
836  			    !dbg_find_orphan(c, inum)) {
837  				ubifs_err(c, "missing orphan, ino %lu",
838  					  (unsigned long)inum);
839  				ci->missing += 1;
840  			}
841  	}
842  	ci->leaf_cnt += 1;
843  	return 0;
844  }
845  
846  static int dbg_read_orphans(struct check_info *ci, struct ubifs_scan_leb *sleb)
847  {
848  	struct ubifs_scan_node *snod;
849  	struct ubifs_orph_node *orph;
850  	ino_t inum;
851  	int i, n, err;
852  
853  	list_for_each_entry(snod, &sleb->nodes, list) {
854  		cond_resched();
855  		if (snod->type != UBIFS_ORPH_NODE)
856  			continue;
857  		orph = snod->node;
858  		n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
859  		for (i = 0; i < n; i++) {
860  			inum = le64_to_cpu(orph->inos[i]);
861  			err = dbg_ins_check_orphan(&ci->root, inum);
862  			if (err)
863  				return err;
864  		}
865  	}
866  	return 0;
867  }
868  
869  static int dbg_scan_orphans(struct ubifs_info *c, struct check_info *ci)
870  {
871  	int lnum, err = 0;
872  	void *buf;
873  
874  	/* Check no-orphans flag and skip this if no orphans */
875  	if (c->no_orphs)
876  		return 0;
877  
878  	buf = __vmalloc(c->leb_size, GFP_NOFS, PAGE_KERNEL);
879  	if (!buf) {
880  		ubifs_err(c, "cannot allocate memory to check orphans");
881  		return 0;
882  	}
883  
884  	for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
885  		struct ubifs_scan_leb *sleb;
886  
887  		sleb = ubifs_scan(c, lnum, 0, buf, 0);
888  		if (IS_ERR(sleb)) {
889  			err = PTR_ERR(sleb);
890  			break;
891  		}
892  
893  		err = dbg_read_orphans(ci, sleb);
894  		ubifs_scan_destroy(sleb);
895  		if (err)
896  			break;
897  	}
898  
899  	vfree(buf);
900  	return err;
901  }
902  
903  static int dbg_check_orphans(struct ubifs_info *c)
904  {
905  	struct check_info ci;
906  	int err;
907  
908  	if (!dbg_is_chk_orph(c))
909  		return 0;
910  
911  	ci.last_ino = 0;
912  	ci.tot_inos = 0;
913  	ci.missing  = 0;
914  	ci.leaf_cnt = 0;
915  	ci.root = RB_ROOT;
916  	ci.node = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
917  	if (!ci.node) {
918  		ubifs_err(c, "out of memory");
919  		return -ENOMEM;
920  	}
921  
922  	err = dbg_scan_orphans(c, &ci);
923  	if (err)
924  		goto out;
925  
926  	err = dbg_walk_index(c, &dbg_orphan_check, NULL, &ci);
927  	if (err) {
928  		ubifs_err(c, "cannot scan TNC, error %d", err);
929  		goto out;
930  	}
931  
932  	if (ci.missing) {
933  		ubifs_err(c, "%lu missing orphan(s)", ci.missing);
934  		err = -EINVAL;
935  		goto out;
936  	}
937  
938  	dbg_cmt("last inode number is %lu", ci.last_ino);
939  	dbg_cmt("total number of inodes is %lu", ci.tot_inos);
940  	dbg_cmt("total number of leaf nodes is %llu", ci.leaf_cnt);
941  
942  out:
943  	dbg_free_check_tree(&ci.root);
944  	kfree(ci.node);
945  	return err;
946  }
947