extent_map.c 23.2 KB
1 2 3 4 5 6 7 8 9 10 11 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 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 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994
/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * extent_map.c
 *
 * Block/Cluster mapping functions
 *
 * Copyright (C) 2004 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License, version 2,  as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/fs.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/fiemap.h>

#include <cluster/masklog.h>

#include "ocfs2.h"

#include "alloc.h"
#include "dlmglue.h"
#include "extent_map.h"
#include "inode.h"
#include "super.h"
#include "symlink.h"
#include "ocfs2_trace.h"

#include "buffer_head_io.h"

/*
 * The extent caching implementation is intentionally trivial.
 *
 * We only cache a small number of extents stored directly on the
 * inode, so linear order operations are acceptable. If we ever want
 * to increase the size of the extent map, then these algorithms must
 * get smarter.
 */

void ocfs2_extent_map_init(struct inode *inode)
{
	struct ocfs2_inode_info *oi = OCFS2_I(inode);

	oi->ip_extent_map.em_num_items = 0;
	INIT_LIST_HEAD(&oi->ip_extent_map.em_list);
}

static void __ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
				      unsigned int cpos,
				      struct ocfs2_extent_map_item **ret_emi)
{
	unsigned int range;
	struct ocfs2_extent_map_item *emi;

	*ret_emi = NULL;

	list_for_each_entry(emi, &em->em_list, ei_list) {
		range = emi->ei_cpos + emi->ei_clusters;

		if (cpos >= emi->ei_cpos && cpos < range) {
			list_move(&emi->ei_list, &em->em_list);

			*ret_emi = emi;
			break;
		}
	}
}

static int ocfs2_extent_map_lookup(struct inode *inode, unsigned int cpos,
				   unsigned int *phys, unsigned int *len,
				   unsigned int *flags)
{
	unsigned int coff;
	struct ocfs2_inode_info *oi = OCFS2_I(inode);
	struct ocfs2_extent_map_item *emi;

	spin_lock(&oi->ip_lock);

	__ocfs2_extent_map_lookup(&oi->ip_extent_map, cpos, &emi);
	if (emi) {
		coff = cpos - emi->ei_cpos;
		*phys = emi->ei_phys + coff;
		if (len)
			*len = emi->ei_clusters - coff;
		if (flags)
			*flags = emi->ei_flags;
	}

	spin_unlock(&oi->ip_lock);

	if (emi == NULL)
		return -ENOENT;

	return 0;
}

/*
 * Forget about all clusters equal to or greater than cpos.
 */
void ocfs2_extent_map_trunc(struct inode *inode, unsigned int cpos)
{
	struct ocfs2_extent_map_item *emi, *n;
	struct ocfs2_inode_info *oi = OCFS2_I(inode);
	struct ocfs2_extent_map *em = &oi->ip_extent_map;
	LIST_HEAD(tmp_list);
	unsigned int range;

	spin_lock(&oi->ip_lock);
	list_for_each_entry_safe(emi, n, &em->em_list, ei_list) {
		if (emi->ei_cpos >= cpos) {
			/* Full truncate of this record. */
			list_move(&emi->ei_list, &tmp_list);
			BUG_ON(em->em_num_items == 0);
			em->em_num_items--;
			continue;
		}

		range = emi->ei_cpos + emi->ei_clusters;
		if (range > cpos) {
			/* Partial truncate */
			emi->ei_clusters = cpos - emi->ei_cpos;
		}
	}
	spin_unlock(&oi->ip_lock);

	list_for_each_entry_safe(emi, n, &tmp_list, ei_list) {
		list_del(&emi->ei_list);
		kfree(emi);
	}
}

/*
 * Is any part of emi2 contained within emi1
 */
static int ocfs2_ei_is_contained(struct ocfs2_extent_map_item *emi1,
				 struct ocfs2_extent_map_item *emi2)
{
	unsigned int range1, range2;

	/*
	 * Check if logical start of emi2 is inside emi1
	 */
	range1 = emi1->ei_cpos + emi1->ei_clusters;
	if (emi2->ei_cpos >= emi1->ei_cpos && emi2->ei_cpos < range1)
		return 1;

	/*
	 * Check if logical end of emi2 is inside emi1
	 */
	range2 = emi2->ei_cpos + emi2->ei_clusters;
	if (range2 > emi1->ei_cpos && range2 <= range1)
		return 1;

	return 0;
}

static void ocfs2_copy_emi_fields(struct ocfs2_extent_map_item *dest,
				  struct ocfs2_extent_map_item *src)
{
	dest->ei_cpos = src->ei_cpos;
	dest->ei_phys = src->ei_phys;
	dest->ei_clusters = src->ei_clusters;
	dest->ei_flags = src->ei_flags;
}

/*
 * Try to merge emi with ins. Returns 1 if merge succeeds, zero
 * otherwise.
 */
static int ocfs2_try_to_merge_extent_map(struct ocfs2_extent_map_item *emi,
					 struct ocfs2_extent_map_item *ins)
{
	/*
	 * Handle contiguousness
	 */
	if (ins->ei_phys == (emi->ei_phys + emi->ei_clusters) &&
	    ins->ei_cpos == (emi->ei_cpos + emi->ei_clusters) &&
	    ins->ei_flags == emi->ei_flags) {
		emi->ei_clusters += ins->ei_clusters;
		return 1;
	} else if ((ins->ei_phys + ins->ei_clusters) == emi->ei_phys &&
		   (ins->ei_cpos + ins->ei_clusters) == emi->ei_cpos &&
		   ins->ei_flags == emi->ei_flags) {
		emi->ei_phys = ins->ei_phys;
		emi->ei_cpos = ins->ei_cpos;
		emi->ei_clusters += ins->ei_clusters;
		return 1;
	}

	/*
	 * Overlapping extents - this shouldn't happen unless we've
	 * split an extent to change it's flags. That is exceedingly
	 * rare, so there's no sense in trying to optimize it yet.
	 */
	if (ocfs2_ei_is_contained(emi, ins) ||
	    ocfs2_ei_is_contained(ins, emi)) {
		ocfs2_copy_emi_fields(emi, ins);
		return 1;
	}

	/* No merge was possible. */
	return 0;
}

/*
 * In order to reduce complexity on the caller, this insert function
 * is intentionally liberal in what it will accept.
 *
 * The only rule is that the truncate call *must* be used whenever
 * records have been deleted. This avoids inserting overlapping
 * records with different physical mappings.
 */
void ocfs2_extent_map_insert_rec(struct inode *inode,
				 struct ocfs2_extent_rec *rec)
{
	struct ocfs2_inode_info *oi = OCFS2_I(inode);
	struct ocfs2_extent_map *em = &oi->ip_extent_map;
	struct ocfs2_extent_map_item *emi, *new_emi = NULL;
	struct ocfs2_extent_map_item ins;

	ins.ei_cpos = le32_to_cpu(rec->e_cpos);
	ins.ei_phys = ocfs2_blocks_to_clusters(inode->i_sb,
					       le64_to_cpu(rec->e_blkno));
	ins.ei_clusters = le16_to_cpu(rec->e_leaf_clusters);
	ins.ei_flags = rec->e_flags;

search:
	spin_lock(&oi->ip_lock);

	list_for_each_entry(emi, &em->em_list, ei_list) {
		if (ocfs2_try_to_merge_extent_map(emi, &ins)) {
			list_move(&emi->ei_list, &em->em_list);
			spin_unlock(&oi->ip_lock);
			goto out;
		}
	}

	/*
	 * No item could be merged.
	 *
	 * Either allocate and add a new item, or overwrite the last recently
	 * inserted.
	 */

	if (em->em_num_items < OCFS2_MAX_EXTENT_MAP_ITEMS) {
		if (new_emi == NULL) {
			spin_unlock(&oi->ip_lock);

			new_emi = kmalloc(sizeof(*new_emi), GFP_NOFS);
			if (new_emi == NULL)
				goto out;

			goto search;
		}

		ocfs2_copy_emi_fields(new_emi, &ins);
		list_add(&new_emi->ei_list, &em->em_list);
		em->em_num_items++;
		new_emi = NULL;
	} else {
		BUG_ON(list_empty(&em->em_list) || em->em_num_items == 0);
		emi = list_entry(em->em_list.prev,
				 struct ocfs2_extent_map_item, ei_list);
		list_move(&emi->ei_list, &em->em_list);
		ocfs2_copy_emi_fields(emi, &ins);
	}

	spin_unlock(&oi->ip_lock);

out:
	kfree(new_emi);
}

static int ocfs2_last_eb_is_empty(struct inode *inode,
				  struct ocfs2_dinode *di)
{
	int ret, next_free;
	u64 last_eb_blk = le64_to_cpu(di->i_last_eb_blk);
	struct buffer_head *eb_bh = NULL;
	struct ocfs2_extent_block *eb;
	struct ocfs2_extent_list *el;

	ret = ocfs2_read_extent_block(INODE_CACHE(inode), last_eb_blk, &eb_bh);
	if (ret) {
		mlog_errno(ret);
		goto out;
	}

	eb = (struct ocfs2_extent_block *) eb_bh->b_data;
	el = &eb->h_list;

	if (el->l_tree_depth) {
		ocfs2_error(inode->i_sb,
			    "Inode %lu has non zero tree depth in "
			    "leaf block %llu\n", inode->i_ino,
			    (unsigned long long)eb_bh->b_blocknr);
		ret = -EROFS;
		goto out;
	}

	next_free = le16_to_cpu(el->l_next_free_rec);

	if (next_free == 0 ||
	    (next_free == 1 && ocfs2_is_empty_extent(&el->l_recs[0])))
		ret = 1;

out:
	brelse(eb_bh);
	return ret;
}

/*
 * Return the 1st index within el which contains an extent start
 * larger than v_cluster.
 */
static int ocfs2_search_for_hole_index(struct ocfs2_extent_list *el,
				       u32 v_cluster)
{
	int i;
	struct ocfs2_extent_rec *rec;

	for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
		rec = &el->l_recs[i];

		if (v_cluster < le32_to_cpu(rec->e_cpos))
			break;
	}

	return i;
}

/*
 * Figure out the size of a hole which starts at v_cluster within the given
 * extent list.
 *
 * If there is no more allocation past v_cluster, we return the maximum
 * cluster size minus v_cluster.
 *
 * If we have in-inode extents, then el points to the dinode list and
 * eb_bh is NULL. Otherwise, eb_bh should point to the extent block
 * containing el.
 */
int ocfs2_figure_hole_clusters(struct ocfs2_caching_info *ci,
			       struct ocfs2_extent_list *el,
			       struct buffer_head *eb_bh,
			       u32 v_cluster,
			       u32 *num_clusters)
{
	int ret, i;
	struct buffer_head *next_eb_bh = NULL;
	struct ocfs2_extent_block *eb, *next_eb;

	i = ocfs2_search_for_hole_index(el, v_cluster);

	if (i == le16_to_cpu(el->l_next_free_rec) && eb_bh) {
		eb = (struct ocfs2_extent_block *)eb_bh->b_data;

		/*
		 * Check the next leaf for any extents.
		 */

		if (le64_to_cpu(eb->h_next_leaf_blk) == 0ULL)
			goto no_more_extents;

		ret = ocfs2_read_extent_block(ci,
					      le64_to_cpu(eb->h_next_leaf_blk),
					      &next_eb_bh);
		if (ret) {
			mlog_errno(ret);
			goto out;
		}

		next_eb = (struct ocfs2_extent_block *)next_eb_bh->b_data;
		el = &next_eb->h_list;
		i = ocfs2_search_for_hole_index(el, v_cluster);
	}

no_more_extents:
	if (i == le16_to_cpu(el->l_next_free_rec)) {
		/*
		 * We're at the end of our existing allocation. Just
		 * return the maximum number of clusters we could
		 * possibly allocate.
		 */
		*num_clusters = UINT_MAX - v_cluster;
	} else {
		*num_clusters = le32_to_cpu(el->l_recs[i].e_cpos) - v_cluster;
	}

	ret = 0;
out:
	brelse(next_eb_bh);
	return ret;
}

static int ocfs2_get_clusters_nocache(struct inode *inode,
				      struct buffer_head *di_bh,
				      u32 v_cluster, unsigned int *hole_len,
				      struct ocfs2_extent_rec *ret_rec,
				      unsigned int *is_last)
{
	int i, ret, tree_height, len;
	struct ocfs2_dinode *di;
	struct ocfs2_extent_block *uninitialized_var(eb);
	struct ocfs2_extent_list *el;
	struct ocfs2_extent_rec *rec;
	struct buffer_head *eb_bh = NULL;

	memset(ret_rec, 0, sizeof(*ret_rec));
	if (is_last)
		*is_last = 0;

	di = (struct ocfs2_dinode *) di_bh->b_data;
	el = &di->id2.i_list;
	tree_height = le16_to_cpu(el->l_tree_depth);

	if (tree_height > 0) {
		ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
				      &eb_bh);
		if (ret) {
			mlog_errno(ret);
			goto out;
		}

		eb = (struct ocfs2_extent_block *) eb_bh->b_data;
		el = &eb->h_list;

		if (el->l_tree_depth) {
			ocfs2_error(inode->i_sb,
				    "Inode %lu has non zero tree depth in "
				    "leaf block %llu\n", inode->i_ino,
				    (unsigned long long)eb_bh->b_blocknr);
			ret = -EROFS;
			goto out;
		}
	}

	i = ocfs2_search_extent_list(el, v_cluster);
	if (i == -1) {
		/*
		 * Holes can be larger than the maximum size of an
		 * extent, so we return their lengths in a separate
		 * field.
		 */
		if (hole_len) {
			ret = ocfs2_figure_hole_clusters(INODE_CACHE(inode),
							 el, eb_bh,
							 v_cluster, &len);
			if (ret) {
				mlog_errno(ret);
				goto out;
			}

			*hole_len = len;
		}
		goto out_hole;
	}

	rec = &el->l_recs[i];

	BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));

	if (!rec->e_blkno) {
		ocfs2_error(inode->i_sb, "Inode %lu has bad extent "
			    "record (%u, %u, 0)", inode->i_ino,
			    le32_to_cpu(rec->e_cpos),
			    ocfs2_rec_clusters(el, rec));
		ret = -EROFS;
		goto out;
	}

	*ret_rec = *rec;

	/*
	 * Checking for last extent is potentially expensive - we
	 * might have to look at the next leaf over to see if it's
	 * empty.
	 *
	 * The first two checks are to see whether the caller even
	 * cares for this information, and if the extent is at least
	 * the last in it's list.
	 *
	 * If those hold true, then the extent is last if any of the
	 * additional conditions hold true:
	 *  - Extent list is in-inode
	 *  - Extent list is right-most
	 *  - Extent list is 2nd to rightmost, with empty right-most
	 */
	if (is_last) {
		if (i == (le16_to_cpu(el->l_next_free_rec) - 1)) {
			if (tree_height == 0)
				*is_last = 1;
			else if (eb->h_blkno == di->i_last_eb_blk)
				*is_last = 1;
			else if (eb->h_next_leaf_blk == di->i_last_eb_blk) {
				ret = ocfs2_last_eb_is_empty(inode, di);
				if (ret < 0) {
					mlog_errno(ret);
					goto out;
				}
				if (ret == 1)
					*is_last = 1;
			}
		}
	}

out_hole:
	ret = 0;
out:
	brelse(eb_bh);
	return ret;
}

static void ocfs2_relative_extent_offsets(struct super_block *sb,
					  u32 v_cluster,
					  struct ocfs2_extent_rec *rec,
					  u32 *p_cluster, u32 *num_clusters)

{
	u32 coff = v_cluster - le32_to_cpu(rec->e_cpos);

	*p_cluster = ocfs2_blocks_to_clusters(sb, le64_to_cpu(rec->e_blkno));
	*p_cluster = *p_cluster + coff;

	if (num_clusters)
		*num_clusters = le16_to_cpu(rec->e_leaf_clusters) - coff;
}

int ocfs2_xattr_get_clusters(struct inode *inode, u32 v_cluster,
			     u32 *p_cluster, u32 *num_clusters,
			     struct ocfs2_extent_list *el,
			     unsigned int *extent_flags)
{
	int ret = 0, i;
	struct buffer_head *eb_bh = NULL;
	struct ocfs2_extent_block *eb;
	struct ocfs2_extent_rec *rec;
	u32 coff;

	if (el->l_tree_depth) {
		ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
				      &eb_bh);
		if (ret) {
			mlog_errno(ret);
			goto out;
		}

		eb = (struct ocfs2_extent_block *) eb_bh->b_data;
		el = &eb->h_list;

		if (el->l_tree_depth) {
			ocfs2_error(inode->i_sb,
				    "Inode %lu has non zero tree depth in "
				    "xattr leaf block %llu\n", inode->i_ino,
				    (unsigned long long)eb_bh->b_blocknr);
			ret = -EROFS;
			goto out;
		}
	}

	i = ocfs2_search_extent_list(el, v_cluster);
	if (i == -1) {
		ret = -EROFS;
		mlog_errno(ret);
		goto out;
	} else {
		rec = &el->l_recs[i];
		BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));

		if (!rec->e_blkno) {
			ocfs2_error(inode->i_sb, "Inode %lu has bad extent "
				    "record (%u, %u, 0) in xattr", inode->i_ino,
				    le32_to_cpu(rec->e_cpos),
				    ocfs2_rec_clusters(el, rec));
			ret = -EROFS;
			goto out;
		}
		coff = v_cluster - le32_to_cpu(rec->e_cpos);
		*p_cluster = ocfs2_blocks_to_clusters(inode->i_sb,
						    le64_to_cpu(rec->e_blkno));
		*p_cluster = *p_cluster + coff;
		if (num_clusters)
			*num_clusters = ocfs2_rec_clusters(el, rec) - coff;

		if (extent_flags)
			*extent_flags = rec->e_flags;
	}
out:
	if (eb_bh)
		brelse(eb_bh);
	return ret;
}

int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
		       u32 *p_cluster, u32 *num_clusters,
		       unsigned int *extent_flags)
{
	int ret;
	unsigned int uninitialized_var(hole_len), flags = 0;
	struct buffer_head *di_bh = NULL;
	struct ocfs2_extent_rec rec;

	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
		ret = -ERANGE;
		mlog_errno(ret);
		goto out;
	}

	ret = ocfs2_extent_map_lookup(inode, v_cluster, p_cluster,
				      num_clusters, extent_flags);
	if (ret == 0)
		goto out;

	ret = ocfs2_read_inode_block(inode, &di_bh);
	if (ret) {
		mlog_errno(ret);
		goto out;
	}

	ret = ocfs2_get_clusters_nocache(inode, di_bh, v_cluster, &hole_len,
					 &rec, NULL);
	if (ret) {
		mlog_errno(ret);
		goto out;
	}

	if (rec.e_blkno == 0ULL) {
		/*
		 * A hole was found. Return some canned values that
		 * callers can key on. If asked for, num_clusters will
		 * be populated with the size of the hole.
		 */
		*p_cluster = 0;
		if (num_clusters) {
			*num_clusters = hole_len;
		}
	} else {
		ocfs2_relative_extent_offsets(inode->i_sb, v_cluster, &rec,
					      p_cluster, num_clusters);
		flags = rec.e_flags;

		ocfs2_extent_map_insert_rec(inode, &rec);
	}

	if (extent_flags)
		*extent_flags = flags;

out:
	brelse(di_bh);
	return ret;
}

/*
 * This expects alloc_sem to be held. The allocation cannot change at
 * all while the map is in the process of being updated.
 */
int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno,
				u64 *ret_count, unsigned int *extent_flags)
{
	int ret;
	int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
	u32 cpos, num_clusters, p_cluster;
	u64 boff = 0;

	cpos = ocfs2_blocks_to_clusters(inode->i_sb, v_blkno);

	ret = ocfs2_get_clusters(inode, cpos, &p_cluster, &num_clusters,
				 extent_flags);
	if (ret) {
		mlog_errno(ret);
		goto out;
	}

	/*
	 * p_cluster == 0 indicates a hole.
	 */
	if (p_cluster) {
		boff = ocfs2_clusters_to_blocks(inode->i_sb, p_cluster);
		boff += (v_blkno & (u64)(bpc - 1));
	}

	*p_blkno = boff;

	if (ret_count) {
		*ret_count = ocfs2_clusters_to_blocks(inode->i_sb, num_clusters);
		*ret_count -= v_blkno & (u64)(bpc - 1);
	}

out:
	return ret;
}

/*
 * The ocfs2_fiemap_inline() may be a little bit misleading, since
 * it not only handles the fiemap for inlined files, but also deals
 * with the fast symlink, cause they have no difference for extent
 * mapping per se.
 */
static int ocfs2_fiemap_inline(struct inode *inode, struct buffer_head *di_bh,
			       struct fiemap_extent_info *fieinfo,
			       u64 map_start)
{
	int ret;
	unsigned int id_count;
	struct ocfs2_dinode *di;
	u64 phys;
	u32 flags = FIEMAP_EXTENT_DATA_INLINE|FIEMAP_EXTENT_LAST;
	struct ocfs2_inode_info *oi = OCFS2_I(inode);

	di = (struct ocfs2_dinode *)di_bh->b_data;
	if (ocfs2_inode_is_fast_symlink(inode))
		id_count = ocfs2_fast_symlink_chars(inode->i_sb);
	else
		id_count = le16_to_cpu(di->id2.i_data.id_count);

	if (map_start < id_count) {
		phys = oi->ip_blkno << inode->i_sb->s_blocksize_bits;
		if (ocfs2_inode_is_fast_symlink(inode))
			phys += offsetof(struct ocfs2_dinode, id2.i_symlink);
		else
			phys += offsetof(struct ocfs2_dinode,
					 id2.i_data.id_data);

		ret = fiemap_fill_next_extent(fieinfo, 0, phys, id_count,
					      flags);
		if (ret < 0)
			return ret;
	}

	return 0;
}

#define OCFS2_FIEMAP_FLAGS	(FIEMAP_FLAG_SYNC)

int ocfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
		 u64 map_start, u64 map_len)
{
	int ret, is_last;
	u32 mapping_end, cpos;
	unsigned int hole_size;
	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
	u64 len_bytes, phys_bytes, virt_bytes;
	struct buffer_head *di_bh = NULL;
	struct ocfs2_extent_rec rec;

	ret = fiemap_check_flags(fieinfo, OCFS2_FIEMAP_FLAGS);
	if (ret)
		return ret;

	ret = ocfs2_inode_lock(inode, &di_bh, 0);
	if (ret) {
		mlog_errno(ret);
		goto out;
	}

	down_read(&OCFS2_I(inode)->ip_alloc_sem);

	/*
	 * Handle inline-data and fast symlink separately.
	 */
	if ((OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) ||
	    ocfs2_inode_is_fast_symlink(inode)) {
		ret = ocfs2_fiemap_inline(inode, di_bh, fieinfo, map_start);
		goto out_unlock;
	}

	cpos = map_start >> osb->s_clustersize_bits;
	mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
					       map_start + map_len);
	is_last = 0;
	while (cpos < mapping_end && !is_last) {
		u32 fe_flags;

		ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos,
						 &hole_size, &rec, &is_last);
		if (ret) {
			mlog_errno(ret);
			goto out_unlock;
		}

		if (rec.e_blkno == 0ULL) {
			cpos += hole_size;
			continue;
		}

		fe_flags = 0;
		if (rec.e_flags & OCFS2_EXT_UNWRITTEN)
			fe_flags |= FIEMAP_EXTENT_UNWRITTEN;
		if (rec.e_flags & OCFS2_EXT_REFCOUNTED)
			fe_flags |= FIEMAP_EXTENT_SHARED;
		if (is_last)
			fe_flags |= FIEMAP_EXTENT_LAST;
		len_bytes = (u64)le16_to_cpu(rec.e_leaf_clusters) << osb->s_clustersize_bits;
		phys_bytes = le64_to_cpu(rec.e_blkno) << osb->sb->s_blocksize_bits;
		virt_bytes = (u64)le32_to_cpu(rec.e_cpos) << osb->s_clustersize_bits;

		ret = fiemap_fill_next_extent(fieinfo, virt_bytes, phys_bytes,
					      len_bytes, fe_flags);
		if (ret)
			break;

		cpos = le32_to_cpu(rec.e_cpos)+ le16_to_cpu(rec.e_leaf_clusters);
	}

	if (ret > 0)
		ret = 0;

out_unlock:
	brelse(di_bh);

	up_read(&OCFS2_I(inode)->ip_alloc_sem);

	ocfs2_inode_unlock(inode, 0);
out:

	return ret;
}

int ocfs2_seek_data_hole_offset(struct file *file, loff_t *offset, int whence)
{
	struct inode *inode = file->f_mapping->host;
	int ret;
	unsigned int is_last = 0, is_data = 0;
	u16 cs_bits = OCFS2_SB(inode->i_sb)->s_clustersize_bits;
	u32 cpos, cend, clen, hole_size;
	u64 extoff, extlen;
	struct buffer_head *di_bh = NULL;
	struct ocfs2_extent_rec rec;

	BUG_ON(whence != SEEK_DATA && whence != SEEK_HOLE);

	ret = ocfs2_inode_lock(inode, &di_bh, 0);
	if (ret) {
		mlog_errno(ret);
		goto out;
	}

	down_read(&OCFS2_I(inode)->ip_alloc_sem);

	if (*offset >= i_size_read(inode)) {
		ret = -ENXIO;
		goto out_unlock;
	}

	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
		if (whence == SEEK_HOLE)
			*offset = i_size_read(inode);
		goto out_unlock;
	}

	clen = 0;
	cpos = *offset >> cs_bits;
	cend = ocfs2_clusters_for_bytes(inode->i_sb, i_size_read(inode));

	while (cpos < cend && !is_last) {
		ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos, &hole_size,
						 &rec, &is_last);
		if (ret) {
			mlog_errno(ret);
			goto out_unlock;
		}

		extoff = cpos;
		extoff <<= cs_bits;

		if (rec.e_blkno == 0ULL) {
			clen = hole_size;
			is_data = 0;
		} else {
			clen = le16_to_cpu(rec.e_leaf_clusters) -
				(cpos - le32_to_cpu(rec.e_cpos));
			is_data = (rec.e_flags & OCFS2_EXT_UNWRITTEN) ?  0 : 1;
		}

		if ((!is_data && whence == SEEK_HOLE) ||
		    (is_data && whence == SEEK_DATA)) {
			if (extoff > *offset)
				*offset = extoff;
			goto out_unlock;
		}

		if (!is_last)
			cpos += clen;
	}

	if (whence == SEEK_HOLE) {
		extoff = cpos;
		extoff <<= cs_bits;
		extlen = clen;
		extlen <<=  cs_bits;

		if ((extoff + extlen) > i_size_read(inode))
			extlen = i_size_read(inode) - extoff;
		extoff += extlen;
		if (extoff > *offset)
			*offset = extoff;
		goto out_unlock;
	}

	ret = -ENXIO;

out_unlock:

	brelse(di_bh);

	up_read(&OCFS2_I(inode)->ip_alloc_sem);

	ocfs2_inode_unlock(inode, 0);
out:
	return ret;
}

int ocfs2_read_virt_blocks(struct inode *inode, u64 v_block, int nr,
			   struct buffer_head *bhs[], int flags,
			   int (*validate)(struct super_block *sb,
					   struct buffer_head *bh))
{
	int rc = 0;
	u64 p_block, p_count;
	int i, count, done = 0;

	trace_ocfs2_read_virt_blocks(
	     inode, (unsigned long long)v_block, nr, bhs, flags,
	     validate);

	if (((v_block + nr - 1) << inode->i_sb->s_blocksize_bits) >=
	    i_size_read(inode)) {
		BUG_ON(!(flags & OCFS2_BH_READAHEAD));
		goto out;
	}

	while (done < nr) {
		down_read(&OCFS2_I(inode)->ip_alloc_sem);
		rc = ocfs2_extent_map_get_blocks(inode, v_block + done,
						 &p_block, &p_count, NULL);
		up_read(&OCFS2_I(inode)->ip_alloc_sem);
		if (rc) {
			mlog_errno(rc);
			break;
		}

		if (!p_block) {
			rc = -EIO;
			mlog(ML_ERROR,
			     "Inode #%llu contains a hole at offset %llu\n",
			     (unsigned long long)OCFS2_I(inode)->ip_blkno,
			     (unsigned long long)(v_block + done) <<
			     inode->i_sb->s_blocksize_bits);
			break;
		}

		count = nr - done;
		if (p_count < count)
			count = p_count;

		/*
		 * If the caller passed us bhs, they should have come
		 * from a previous readahead call to this function.  Thus,
		 * they should have the right b_blocknr.
		 */
		for (i = 0; i < count; i++) {
			if (!bhs[done + i])
				continue;
			BUG_ON(bhs[done + i]->b_blocknr != (p_block + i));
		}

		rc = ocfs2_read_blocks(INODE_CACHE(inode), p_block, count,
				       bhs + done, flags, validate);
		if (rc) {
			mlog_errno(rc);
			break;
		}
		done += count;
	}

out:
	return rc;
}