orphan.c 24.1 KB
Newer Older
1 2 3 4 5
/*
 * This file is part of UBIFS.
 *
 * Copyright (C) 2006-2008 Nokia Corporation.
 *
6
 * SPDX-License-Identifier:	GPL-2.0+
7 8 9 10
 *
 * Author: Adrian Hunter
 */

11
#include <linux/err.h>
12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44
#include "ubifs.h"

/*
 * An orphan is an inode number whose inode node has been committed to the index
 * with a link count of zero. That happens when an open file is deleted
 * (unlinked) and then a commit is run. In the normal course of events the inode
 * would be deleted when the file is closed. However in the case of an unclean
 * unmount, orphans need to be accounted for. After an unclean unmount, the
 * orphans' inodes must be deleted which means either scanning the entire index
 * looking for them, or keeping a list on flash somewhere. This unit implements
 * the latter approach.
 *
 * The orphan area is a fixed number of LEBs situated between the LPT area and
 * the main area. The number of orphan area LEBs is specified when the file
 * system is created. The minimum number is 1. The size of the orphan area
 * should be so that it can hold the maximum number of orphans that are expected
 * to ever exist at one time.
 *
 * The number of orphans that can fit in a LEB is:
 *
 *         (c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64)
 *
 * For example: a 15872 byte LEB can fit 1980 orphans so 1 LEB may be enough.
 *
 * Orphans are accumulated in a rb-tree. When an inode's link count drops to
 * zero, the inode number is added to the rb-tree. It is removed from the tree
 * when the inode is deleted.  Any new orphans that are in the orphan tree when
 * the commit is run, are written to the orphan area in 1 or more orphan nodes.
 * If the orphan area is full, it is consolidated to make space.  There is
 * always enough space because validation prevents the user from creating more
 * than the maximum number of orphans allowed.
 */

45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80
static int dbg_check_orphans(struct ubifs_info *c);

/**
 * ubifs_add_orphan - add an orphan.
 * @c: UBIFS file-system description object
 * @inum: orphan inode number
 *
 * Add an orphan. This function is called when an inodes link count drops to
 * zero.
 */
int ubifs_add_orphan(struct ubifs_info *c, ino_t inum)
{
	struct ubifs_orphan *orphan, *o;
	struct rb_node **p, *parent = NULL;

	orphan = kzalloc(sizeof(struct ubifs_orphan), GFP_NOFS);
	if (!orphan)
		return -ENOMEM;
	orphan->inum = inum;
	orphan->new = 1;

	spin_lock(&c->orphan_lock);
	if (c->tot_orphans >= c->max_orphans) {
		spin_unlock(&c->orphan_lock);
		kfree(orphan);
		return -ENFILE;
	}
	p = &c->orph_tree.rb_node;
	while (*p) {
		parent = *p;
		o = rb_entry(parent, struct ubifs_orphan, rb);
		if (inum < o->inum)
			p = &(*p)->rb_left;
		else if (inum > o->inum)
			p = &(*p)->rb_right;
		else {
81
			ubifs_err(c, "orphaned twice");
82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147
			spin_unlock(&c->orphan_lock);
			kfree(orphan);
			return 0;
		}
	}
	c->tot_orphans += 1;
	c->new_orphans += 1;
	rb_link_node(&orphan->rb, parent, p);
	rb_insert_color(&orphan->rb, &c->orph_tree);
	list_add_tail(&orphan->list, &c->orph_list);
	list_add_tail(&orphan->new_list, &c->orph_new);
	spin_unlock(&c->orphan_lock);
	dbg_gen("ino %lu", (unsigned long)inum);
	return 0;
}

/**
 * ubifs_delete_orphan - delete an orphan.
 * @c: UBIFS file-system description object
 * @inum: orphan inode number
 *
 * Delete an orphan. This function is called when an inode is deleted.
 */
void ubifs_delete_orphan(struct ubifs_info *c, ino_t inum)
{
	struct ubifs_orphan *o;
	struct rb_node *p;

	spin_lock(&c->orphan_lock);
	p = c->orph_tree.rb_node;
	while (p) {
		o = rb_entry(p, struct ubifs_orphan, rb);
		if (inum < o->inum)
			p = p->rb_left;
		else if (inum > o->inum)
			p = p->rb_right;
		else {
			if (o->del) {
				spin_unlock(&c->orphan_lock);
				dbg_gen("deleted twice ino %lu",
					(unsigned long)inum);
				return;
			}
			if (o->cmt) {
				o->del = 1;
				o->dnext = c->orph_dnext;
				c->orph_dnext = o;
				spin_unlock(&c->orphan_lock);
				dbg_gen("delete later ino %lu",
					(unsigned long)inum);
				return;
			}
			rb_erase(p, &c->orph_tree);
			list_del(&o->list);
			c->tot_orphans -= 1;
			if (o->new) {
				list_del(&o->new_list);
				c->new_orphans -= 1;
			}
			spin_unlock(&c->orphan_lock);
			kfree(o);
			dbg_gen("inum %lu", (unsigned long)inum);
			return;
		}
	}
	spin_unlock(&c->orphan_lock);
148
	ubifs_err(c, "missing orphan ino %lu", (unsigned long)inum);
149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204
	dump_stack();
}

/**
 * ubifs_orphan_start_commit - start commit of orphans.
 * @c: UBIFS file-system description object
 *
 * Start commit of orphans.
 */
int ubifs_orphan_start_commit(struct ubifs_info *c)
{
	struct ubifs_orphan *orphan, **last;

	spin_lock(&c->orphan_lock);
	last = &c->orph_cnext;
	list_for_each_entry(orphan, &c->orph_new, new_list) {
		ubifs_assert(orphan->new);
		ubifs_assert(!orphan->cmt);
		orphan->new = 0;
		orphan->cmt = 1;
		*last = orphan;
		last = &orphan->cnext;
	}
	*last = NULL;
	c->cmt_orphans = c->new_orphans;
	c->new_orphans = 0;
	dbg_cmt("%d orphans to commit", c->cmt_orphans);
	INIT_LIST_HEAD(&c->orph_new);
	if (c->tot_orphans == 0)
		c->no_orphs = 1;
	else
		c->no_orphs = 0;
	spin_unlock(&c->orphan_lock);
	return 0;
}

/**
 * avail_orphs - calculate available space.
 * @c: UBIFS file-system description object
 *
 * This function returns the number of orphans that can be written in the
 * available space.
 */
static int avail_orphs(struct ubifs_info *c)
{
	int avail_lebs, avail, gap;

	avail_lebs = c->orph_lebs - (c->ohead_lnum - c->orph_first) - 1;
	avail = avail_lebs *
	       ((c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64));
	gap = c->leb_size - c->ohead_offs;
	if (gap >= UBIFS_ORPH_NODE_SZ + sizeof(__le64))
		avail += (gap - UBIFS_ORPH_NODE_SZ) / sizeof(__le64);
	return avail;
}

205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221
/**
 * tot_avail_orphs - calculate total space.
 * @c: UBIFS file-system description object
 *
 * This function returns the number of orphans that can be written in half
 * the total space. That leaves half the space for adding new orphans.
 */
static int tot_avail_orphs(struct ubifs_info *c)
{
	int avail_lebs, avail;

	avail_lebs = c->orph_lebs;
	avail = avail_lebs *
	       ((c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64));
	return avail / 2;
}

222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279
/**
 * do_write_orph_node - write a node to the orphan head.
 * @c: UBIFS file-system description object
 * @len: length of node
 * @atomic: write atomically
 *
 * This function writes a node to the orphan head from the orphan buffer. If
 * %atomic is not zero, then the write is done atomically. On success, %0 is
 * returned, otherwise a negative error code is returned.
 */
static int do_write_orph_node(struct ubifs_info *c, int len, int atomic)
{
	int err = 0;

	if (atomic) {
		ubifs_assert(c->ohead_offs == 0);
		ubifs_prepare_node(c, c->orph_buf, len, 1);
		len = ALIGN(len, c->min_io_size);
		err = ubifs_leb_change(c, c->ohead_lnum, c->orph_buf, len);
	} else {
		if (c->ohead_offs == 0) {
			/* Ensure LEB has been unmapped */
			err = ubifs_leb_unmap(c, c->ohead_lnum);
			if (err)
				return err;
		}
		err = ubifs_write_node(c, c->orph_buf, len, c->ohead_lnum,
				       c->ohead_offs);
	}
	return err;
}

/**
 * write_orph_node - write an orphan node.
 * @c: UBIFS file-system description object
 * @atomic: write atomically
 *
 * This function builds an orphan node from the cnext list and writes it to the
 * orphan head. On success, %0 is returned, otherwise a negative error code
 * is returned.
 */
static int write_orph_node(struct ubifs_info *c, int atomic)
{
	struct ubifs_orphan *orphan, *cnext;
	struct ubifs_orph_node *orph;
	int gap, err, len, cnt, i;

	ubifs_assert(c->cmt_orphans > 0);
	gap = c->leb_size - c->ohead_offs;
	if (gap < UBIFS_ORPH_NODE_SZ + sizeof(__le64)) {
		c->ohead_lnum += 1;
		c->ohead_offs = 0;
		gap = c->leb_size;
		if (c->ohead_lnum > c->orph_last) {
			/*
			 * We limit the number of orphans so that this should
			 * never happen.
			 */
280
			ubifs_err(c, "out of space in orphan area");
281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389
			return -EINVAL;
		}
	}
	cnt = (gap - UBIFS_ORPH_NODE_SZ) / sizeof(__le64);
	if (cnt > c->cmt_orphans)
		cnt = c->cmt_orphans;
	len = UBIFS_ORPH_NODE_SZ + cnt * sizeof(__le64);
	ubifs_assert(c->orph_buf);
	orph = c->orph_buf;
	orph->ch.node_type = UBIFS_ORPH_NODE;
	spin_lock(&c->orphan_lock);
	cnext = c->orph_cnext;
	for (i = 0; i < cnt; i++) {
		orphan = cnext;
		ubifs_assert(orphan->cmt);
		orph->inos[i] = cpu_to_le64(orphan->inum);
		orphan->cmt = 0;
		cnext = orphan->cnext;
		orphan->cnext = NULL;
	}
	c->orph_cnext = cnext;
	c->cmt_orphans -= cnt;
	spin_unlock(&c->orphan_lock);
	if (c->cmt_orphans)
		orph->cmt_no = cpu_to_le64(c->cmt_no);
	else
		/* Mark the last node of the commit */
		orph->cmt_no = cpu_to_le64((c->cmt_no) | (1ULL << 63));
	ubifs_assert(c->ohead_offs + len <= c->leb_size);
	ubifs_assert(c->ohead_lnum >= c->orph_first);
	ubifs_assert(c->ohead_lnum <= c->orph_last);
	err = do_write_orph_node(c, len, atomic);
	c->ohead_offs += ALIGN(len, c->min_io_size);
	c->ohead_offs = ALIGN(c->ohead_offs, 8);
	return err;
}

/**
 * write_orph_nodes - write orphan nodes until there are no more to commit.
 * @c: UBIFS file-system description object
 * @atomic: write atomically
 *
 * This function writes orphan nodes for all the orphans to commit. On success,
 * %0 is returned, otherwise a negative error code is returned.
 */
static int write_orph_nodes(struct ubifs_info *c, int atomic)
{
	int err;

	while (c->cmt_orphans > 0) {
		err = write_orph_node(c, atomic);
		if (err)
			return err;
	}
	if (atomic) {
		int lnum;

		/* Unmap any unused LEBs after consolidation */
		for (lnum = c->ohead_lnum + 1; lnum <= c->orph_last; lnum++) {
			err = ubifs_leb_unmap(c, lnum);
			if (err)
				return err;
		}
	}
	return 0;
}

/**
 * consolidate - consolidate the orphan area.
 * @c: UBIFS file-system description object
 *
 * This function enables consolidation by putting all the orphans into the list
 * to commit. The list is in the order that the orphans were added, and the
 * LEBs are written atomically in order, so at no time can orphans be lost by
 * an unclean unmount.
 *
 * This function returns %0 on success and a negative error code on failure.
 */
static int consolidate(struct ubifs_info *c)
{
	int tot_avail = tot_avail_orphs(c), err = 0;

	spin_lock(&c->orphan_lock);
	dbg_cmt("there is space for %d orphans and there are %d",
		tot_avail, c->tot_orphans);
	if (c->tot_orphans - c->new_orphans <= tot_avail) {
		struct ubifs_orphan *orphan, **last;
		int cnt = 0;

		/* Change the cnext list to include all non-new orphans */
		last = &c->orph_cnext;
		list_for_each_entry(orphan, &c->orph_list, list) {
			if (orphan->new)
				continue;
			orphan->cmt = 1;
			*last = orphan;
			last = &orphan->cnext;
			cnt += 1;
		}
		*last = NULL;
		ubifs_assert(cnt == c->tot_orphans - c->new_orphans);
		c->cmt_orphans = cnt;
		c->ohead_lnum = c->orph_first;
		c->ohead_offs = 0;
	} else {
		/*
		 * We limit the number of orphans so that this should
		 * never happen.
		 */
390
		ubifs_err(c, "out of space in orphan area");
391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470
		err = -EINVAL;
	}
	spin_unlock(&c->orphan_lock);
	return err;
}

/**
 * commit_orphans - commit orphans.
 * @c: UBIFS file-system description object
 *
 * This function commits orphans to flash. On success, %0 is returned,
 * otherwise a negative error code is returned.
 */
static int commit_orphans(struct ubifs_info *c)
{
	int avail, atomic = 0, err;

	ubifs_assert(c->cmt_orphans > 0);
	avail = avail_orphs(c);
	if (avail < c->cmt_orphans) {
		/* Not enough space to write new orphans, so consolidate */
		err = consolidate(c);
		if (err)
			return err;
		atomic = 1;
	}
	err = write_orph_nodes(c, atomic);
	return err;
}

/**
 * erase_deleted - erase the orphans marked for deletion.
 * @c: UBIFS file-system description object
 *
 * During commit, the orphans being committed cannot be deleted, so they are
 * marked for deletion and deleted by this function. Also, the recovery
 * adds killed orphans to the deletion list, and therefore they are deleted
 * here too.
 */
static void erase_deleted(struct ubifs_info *c)
{
	struct ubifs_orphan *orphan, *dnext;

	spin_lock(&c->orphan_lock);
	dnext = c->orph_dnext;
	while (dnext) {
		orphan = dnext;
		dnext = orphan->dnext;
		ubifs_assert(!orphan->new);
		ubifs_assert(orphan->del);
		rb_erase(&orphan->rb, &c->orph_tree);
		list_del(&orphan->list);
		c->tot_orphans -= 1;
		dbg_gen("deleting orphan ino %lu", (unsigned long)orphan->inum);
		kfree(orphan);
	}
	c->orph_dnext = NULL;
	spin_unlock(&c->orphan_lock);
}

/**
 * ubifs_orphan_end_commit - end commit of orphans.
 * @c: UBIFS file-system description object
 *
 * End commit of orphans.
 */
int ubifs_orphan_end_commit(struct ubifs_info *c)
{
	int err;

	if (c->cmt_orphans != 0) {
		err = commit_orphans(c);
		if (err)
			return err;
	}
	erase_deleted(c);
	err = dbg_check_orphans(c);
	return err;
}

471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529
/**
 * ubifs_clear_orphans - erase all LEBs used for orphans.
 * @c: UBIFS file-system description object
 *
 * If recovery is not required, then the orphans from the previous session
 * are not needed. This function locates the LEBs used to record
 * orphans, and un-maps them.
 */
int ubifs_clear_orphans(struct ubifs_info *c)
{
	int lnum, err;

	for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
		err = ubifs_leb_unmap(c, lnum);
		if (err)
			return err;
	}
	c->ohead_lnum = c->orph_first;
	c->ohead_offs = 0;
	return 0;
}

/**
 * insert_dead_orphan - insert an orphan.
 * @c: UBIFS file-system description object
 * @inum: orphan inode number
 *
 * This function is a helper to the 'do_kill_orphans()' function. The orphan
 * must be kept until the next commit, so it is added to the rb-tree and the
 * deletion list.
 */
static int insert_dead_orphan(struct ubifs_info *c, ino_t inum)
{
	struct ubifs_orphan *orphan, *o;
	struct rb_node **p, *parent = NULL;

	orphan = kzalloc(sizeof(struct ubifs_orphan), GFP_KERNEL);
	if (!orphan)
		return -ENOMEM;
	orphan->inum = inum;

	p = &c->orph_tree.rb_node;
	while (*p) {
		parent = *p;
		o = rb_entry(parent, struct ubifs_orphan, rb);
		if (inum < o->inum)
			p = &(*p)->rb_left;
		else if (inum > o->inum)
			p = &(*p)->rb_right;
		else {
			/* Already added - no problem */
			kfree(orphan);
			return 0;
		}
	}
	c->tot_orphans += 1;
	rb_link_node(&orphan->rb, parent, p);
	rb_insert_color(&orphan->rb, &c->orph_tree);
	list_add_tail(&orphan->list, &c->orph_list);
530
	orphan->del = 1;
531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561
	orphan->dnext = c->orph_dnext;
	c->orph_dnext = orphan;
	dbg_mnt("ino %lu, new %d, tot %d", (unsigned long)inum,
		c->new_orphans, c->tot_orphans);
	return 0;
}

/**
 * do_kill_orphans - remove orphan inodes from the index.
 * @c: UBIFS file-system description object
 * @sleb: scanned LEB
 * @last_cmt_no: cmt_no of last orphan node read is passed and returned here
 * @outofdate: whether the LEB is out of date is returned here
 * @last_flagged: whether the end orphan node is encountered
 *
 * This function is a helper to the 'kill_orphans()' function. It goes through
 * every orphan node in a LEB and for every inode number recorded, removes
 * all keys for that inode from the TNC.
 */
static int do_kill_orphans(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
			   unsigned long long *last_cmt_no, int *outofdate,
			   int *last_flagged)
{
	struct ubifs_scan_node *snod;
	struct ubifs_orph_node *orph;
	unsigned long long cmt_no;
	ino_t inum;
	int i, n, err, first = 1;

	list_for_each_entry(snod, &sleb->nodes, list) {
		if (snod->type != UBIFS_ORPH_NODE) {
562
			ubifs_err(c, "invalid node type %d in orphan area at %d:%d",
563 564
				  snod->type, sleb->lnum, snod->offs);
			ubifs_dump_node(c, snod->node);
565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588
			return -EINVAL;
		}

		orph = snod->node;

		/* Check commit number */
		cmt_no = le64_to_cpu(orph->cmt_no) & LLONG_MAX;
		/*
		 * The commit number on the master node may be less, because
		 * of a failed commit. If there are several failed commits in a
		 * row, the commit number written on orphan nodes will continue
		 * to increase (because the commit number is adjusted here) even
		 * though the commit number on the master node stays the same
		 * because the master node has not been re-written.
		 */
		if (cmt_no > c->cmt_no)
			c->cmt_no = cmt_no;
		if (cmt_no < *last_cmt_no && *last_flagged) {
			/*
			 * The last orphan node had a higher commit number and
			 * was flagged as the last written for that commit
			 * number. That makes this orphan node, out of date.
			 */
			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);
592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663
				return -EINVAL;
			}
			dbg_rcvry("out of date LEB %d", sleb->lnum);
			*outofdate = 1;
			return 0;
		}

		if (first)
			first = 0;

		n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
		for (i = 0; i < n; i++) {
			inum = le64_to_cpu(orph->inos[i]);
			dbg_rcvry("deleting orphaned inode %lu",
				  (unsigned long)inum);
			err = ubifs_tnc_remove_ino(c, inum);
			if (err)
				return err;
			err = insert_dead_orphan(c, inum);
			if (err)
				return err;
		}

		*last_cmt_no = cmt_no;
		if (le64_to_cpu(orph->cmt_no) & (1ULL << 63)) {
			dbg_rcvry("last orph node for commit %llu at %d:%d",
				  cmt_no, sleb->lnum, snod->offs);
			*last_flagged = 1;
		} else
			*last_flagged = 0;
	}

	return 0;
}

/**
 * kill_orphans - remove all orphan inodes from the index.
 * @c: UBIFS file-system description object
 *
 * If recovery is required, then orphan inodes recorded during the previous
 * session (which ended with an unclean unmount) must be deleted from the index.
 * This is done by updating the TNC, but since the index is not updated until
 * the next commit, the LEBs where the orphan information is recorded are not
 * erased until the next commit.
 */
static int kill_orphans(struct ubifs_info *c)
{
	unsigned long long last_cmt_no = 0;
	int lnum, err = 0, outofdate = 0, last_flagged = 0;

	c->ohead_lnum = c->orph_first;
	c->ohead_offs = 0;
	/* Check no-orphans flag and skip this if no orphans */
	if (c->no_orphs) {
		dbg_rcvry("no orphans");
		return 0;
	}
	/*
	 * Orph nodes always start at c->orph_first and are written to each
	 * successive LEB in turn. Generally unused LEBs will have been unmapped
	 * but may contain out of date orphan nodes if the unmap didn't go
	 * through. In addition, the last orphan node written for each commit is
	 * marked (top bit of orph->cmt_no is set to 1). It is possible that
	 * there are orphan nodes from the next commit (i.e. the commit did not
	 * complete successfully). In that case, no orphans will have been lost
	 * due to the way that orphans are written, and any orphans added will
	 * be valid orphans anyway and so can be deleted.
	 */
	for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
		struct ubifs_scan_leb *sleb;

		dbg_rcvry("LEB %d", lnum);
664
		sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
665
		if (IS_ERR(sleb)) {
666 667 668
			if (PTR_ERR(sleb) == -EUCLEAN)
				sleb = ubifs_recover_leb(c, lnum, 0,
							 c->sbuf, -1);
669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717
			if (IS_ERR(sleb)) {
				err = PTR_ERR(sleb);
				break;
			}
		}
		err = do_kill_orphans(c, sleb, &last_cmt_no, &outofdate,
				      &last_flagged);
		if (err || outofdate) {
			ubifs_scan_destroy(sleb);
			break;
		}
		if (sleb->endpt) {
			c->ohead_lnum = lnum;
			c->ohead_offs = sleb->endpt;
		}
		ubifs_scan_destroy(sleb);
	}
	return err;
}

/**
 * ubifs_mount_orphans - delete orphan inodes and erase LEBs that recorded them.
 * @c: UBIFS file-system description object
 * @unclean: indicates recovery from unclean unmount
 * @read_only: indicates read only mount
 *
 * This function is called when mounting to erase orphans from the previous
 * session. If UBIFS was not unmounted cleanly, then the inodes recorded as
 * orphans are deleted.
 */
int ubifs_mount_orphans(struct ubifs_info *c, int unclean, int read_only)
{
	int err = 0;

	c->max_orphans = tot_avail_orphs(c);

	if (!read_only) {
		c->orph_buf = vmalloc(c->leb_size);
		if (!c->orph_buf)
			return -ENOMEM;
	}

	if (unclean)
		err = kill_orphans(c);
	else if (!read_only)
		err = ubifs_clear_orphans(c);

	return err;
}
718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823

/*
 * Everything below is related to debugging.
 */

struct check_orphan {
	struct rb_node rb;
	ino_t inum;
};

struct check_info {
	unsigned long last_ino;
	unsigned long tot_inos;
	unsigned long missing;
	unsigned long long leaf_cnt;
	struct ubifs_ino_node *node;
	struct rb_root root;
};

static int dbg_find_orphan(struct ubifs_info *c, ino_t inum)
{
	struct ubifs_orphan *o;
	struct rb_node *p;

	spin_lock(&c->orphan_lock);
	p = c->orph_tree.rb_node;
	while (p) {
		o = rb_entry(p, struct ubifs_orphan, rb);
		if (inum < o->inum)
			p = p->rb_left;
		else if (inum > o->inum)
			p = p->rb_right;
		else {
			spin_unlock(&c->orphan_lock);
			return 1;
		}
	}
	spin_unlock(&c->orphan_lock);
	return 0;
}

static int dbg_ins_check_orphan(struct rb_root *root, ino_t inum)
{
	struct check_orphan *orphan, *o;
	struct rb_node **p, *parent = NULL;

	orphan = kzalloc(sizeof(struct check_orphan), GFP_NOFS);
	if (!orphan)
		return -ENOMEM;
	orphan->inum = inum;

	p = &root->rb_node;
	while (*p) {
		parent = *p;
		o = rb_entry(parent, struct check_orphan, rb);
		if (inum < o->inum)
			p = &(*p)->rb_left;
		else if (inum > o->inum)
			p = &(*p)->rb_right;
		else {
			kfree(orphan);
			return 0;
		}
	}
	rb_link_node(&orphan->rb, parent, p);
	rb_insert_color(&orphan->rb, root);
	return 0;
}

static int dbg_find_check_orphan(struct rb_root *root, ino_t inum)
{
	struct check_orphan *o;
	struct rb_node *p;

	p = root->rb_node;
	while (p) {
		o = rb_entry(p, struct check_orphan, rb);
		if (inum < o->inum)
			p = p->rb_left;
		else if (inum > o->inum)
			p = p->rb_right;
		else
			return 1;
	}
	return 0;
}

static void dbg_free_check_tree(struct rb_root *root)
{
	struct check_orphan *o, *n;

	rbtree_postorder_for_each_entry_safe(o, n, root, rb)
		kfree(o);
}

static int dbg_orphan_check(struct ubifs_info *c, struct ubifs_zbranch *zbr,
			    void *priv)
{
	struct check_info *ci = priv;
	ino_t inum;
	int err;

	inum = key_inum(c, &zbr->key);
	if (inum != ci->last_ino) {
		/* Lowest node type is the inode node, so it comes first */
		if (key_type(c, &zbr->key) != UBIFS_INO_KEY)
824
			ubifs_err(c, "found orphan node ino %lu, type %d",
825 826 827 828 829
				  (unsigned long)inum, key_type(c, &zbr->key));
		ci->last_ino = inum;
		ci->tot_inos += 1;
		err = ubifs_tnc_read_node(c, zbr, ci->node);
		if (err) {
830
			ubifs_err(c, "node read failed, error %d", err);
831 832 833 834 835 836
			return err;
		}
		if (ci->node->nlink == 0)
			/* Must be recorded as an orphan */
			if (!dbg_find_check_orphan(&ci->root, inum) &&
			    !dbg_find_orphan(c, inum)) {
837
				ubifs_err(c, "missing orphan, ino %lu",
838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879
					  (unsigned long)inum);
				ci->missing += 1;
			}
	}
	ci->leaf_cnt += 1;
	return 0;
}

static int dbg_read_orphans(struct check_info *ci, struct ubifs_scan_leb *sleb)
{
	struct ubifs_scan_node *snod;
	struct ubifs_orph_node *orph;
	ino_t inum;
	int i, n, err;

	list_for_each_entry(snod, &sleb->nodes, list) {
		cond_resched();
		if (snod->type != UBIFS_ORPH_NODE)
			continue;
		orph = snod->node;
		n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
		for (i = 0; i < n; i++) {
			inum = le64_to_cpu(orph->inos[i]);
			err = dbg_ins_check_orphan(&ci->root, inum);
			if (err)
				return err;
		}
	}
	return 0;
}

static int dbg_scan_orphans(struct ubifs_info *c, struct check_info *ci)
{
	int lnum, err = 0;
	void *buf;

	/* Check no-orphans flag and skip this if no orphans */
	if (c->no_orphs)
		return 0;

	buf = __vmalloc(c->leb_size, GFP_NOFS, PAGE_KERNEL);
	if (!buf) {
880
		ubifs_err(c, "cannot allocate memory to check orphans");
881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917
		return 0;
	}

	for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
		struct ubifs_scan_leb *sleb;

		sleb = ubifs_scan(c, lnum, 0, buf, 0);
		if (IS_ERR(sleb)) {
			err = PTR_ERR(sleb);
			break;
		}

		err = dbg_read_orphans(ci, sleb);
		ubifs_scan_destroy(sleb);
		if (err)
			break;
	}

	vfree(buf);
	return err;
}

static int dbg_check_orphans(struct ubifs_info *c)
{
	struct check_info ci;
	int err;

	if (!dbg_is_chk_orph(c))
		return 0;

	ci.last_ino = 0;
	ci.tot_inos = 0;
	ci.missing  = 0;
	ci.leaf_cnt = 0;
	ci.root = RB_ROOT;
	ci.node = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
	if (!ci.node) {
918
		ubifs_err(c, "out of memory");
919 920 921 922 923 924 925 926 927
		return -ENOMEM;
	}

	err = dbg_scan_orphans(c, &ci);
	if (err)
		goto out;

	err = dbg_walk_index(c, &dbg_orphan_check, NULL, &ci);
	if (err) {
928
		ubifs_err(c, "cannot scan TNC, error %d", err);
929 930 931 932
		goto out;
	}

	if (ci.missing) {
933
		ubifs_err(c, "%lu missing orphan(s)", ci.missing);
934 935 936 937 938 939 940 941 942 943 944 945 946
		err = -EINVAL;
		goto out;
	}

	dbg_cmt("last inode number is %lu", ci.last_ino);
	dbg_cmt("total number of inodes is %lu", ci.tot_inos);
	dbg_cmt("total number of leaf nodes is %llu", ci.leaf_cnt);

out:
	dbg_free_check_tree(&ci.root);
	kfree(ci.node);
	return err;
}