1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * extent_map.c
   4 *
   5 * Block/Cluster mapping functions
   6 *
   7 * Copyright (C) 2004 Oracle.  All rights reserved.
   8 */
   9
  10#include <linux/fs.h>
  11#include <linux/init.h>
  12#include <linux/slab.h>
  13#include <linux/types.h>
  14#include <linux/fiemap.h>
  15
  16#include <cluster/masklog.h>
  17
  18#include "ocfs2.h"
  19
  20#include "alloc.h"
  21#include "dlmglue.h"
  22#include "extent_map.h"
  23#include "inode.h"
  24#include "super.h"
  25#include "symlink.h"
  26#include "aops.h"
  27#include "ocfs2_trace.h"
  28
  29#include "buffer_head_io.h"
  30
  31/*
  32 * The extent caching implementation is intentionally trivial.
  33 *
  34 * We only cache a small number of extents stored directly on the
  35 * inode, so linear order operations are acceptable. If we ever want
  36 * to increase the size of the extent map, then these algorithms must
  37 * get smarter.
  38 */
  39
  40void ocfs2_extent_map_init(struct inode *inode)
  41{
  42	struct ocfs2_inode_info *oi = OCFS2_I(inode);
  43
  44	oi->ip_extent_map.em_num_items = 0;
  45	INIT_LIST_HEAD(&oi->ip_extent_map.em_list);
  46}
  47
  48static void __ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
  49				      unsigned int cpos,
  50				      struct ocfs2_extent_map_item **ret_emi)
  51{
  52	unsigned int range;
  53	struct ocfs2_extent_map_item *emi;
  54
  55	*ret_emi = NULL;
  56
  57	list_for_each_entry(emi, &em->em_list, ei_list) {
  58		range = emi->ei_cpos + emi->ei_clusters;
  59
  60		if (cpos >= emi->ei_cpos && cpos < range) {
  61			list_move(&emi->ei_list, &em->em_list);
  62
  63			*ret_emi = emi;
  64			break;
  65		}
  66	}
  67}
  68
  69static int ocfs2_extent_map_lookup(struct inode *inode, unsigned int cpos,
  70				   unsigned int *phys, unsigned int *len,
  71				   unsigned int *flags)
  72{
  73	unsigned int coff;
  74	struct ocfs2_inode_info *oi = OCFS2_I(inode);
  75	struct ocfs2_extent_map_item *emi;
  76
  77	spin_lock(&oi->ip_lock);
  78
  79	__ocfs2_extent_map_lookup(&oi->ip_extent_map, cpos, &emi);
  80	if (emi) {
  81		coff = cpos - emi->ei_cpos;
  82		*phys = emi->ei_phys + coff;
  83		if (len)
  84			*len = emi->ei_clusters - coff;
  85		if (flags)
  86			*flags = emi->ei_flags;
  87	}
  88
  89	spin_unlock(&oi->ip_lock);
  90
  91	if (emi == NULL)
  92		return -ENOENT;
  93
  94	return 0;
  95}
  96
  97/*
  98 * Forget about all clusters equal to or greater than cpos.
  99 */
 100void ocfs2_extent_map_trunc(struct inode *inode, unsigned int cpos)
 101{
 102	struct ocfs2_extent_map_item *emi, *n;
 103	struct ocfs2_inode_info *oi = OCFS2_I(inode);
 104	struct ocfs2_extent_map *em = &oi->ip_extent_map;
 105	LIST_HEAD(tmp_list);
 106	unsigned int range;
 107
 108	spin_lock(&oi->ip_lock);
 109	list_for_each_entry_safe(emi, n, &em->em_list, ei_list) {
 110		if (emi->ei_cpos >= cpos) {
 111			/* Full truncate of this record. */
 112			list_move(&emi->ei_list, &tmp_list);
 113			BUG_ON(em->em_num_items == 0);
 114			em->em_num_items--;
 115			continue;
 116		}
 117
 118		range = emi->ei_cpos + emi->ei_clusters;
 119		if (range > cpos) {
 120			/* Partial truncate */
 121			emi->ei_clusters = cpos - emi->ei_cpos;
 122		}
 123	}
 124	spin_unlock(&oi->ip_lock);
 125
 126	list_for_each_entry_safe(emi, n, &tmp_list, ei_list) {
 127		list_del(&emi->ei_list);
 128		kfree(emi);
 129	}
 130}
 131
 132/*
 133 * Is any part of emi2 contained within emi1
 134 */
 135static int ocfs2_ei_is_contained(struct ocfs2_extent_map_item *emi1,
 136				 struct ocfs2_extent_map_item *emi2)
 137{
 138	unsigned int range1, range2;
 139
 140	/*
 141	 * Check if logical start of emi2 is inside emi1
 142	 */
 143	range1 = emi1->ei_cpos + emi1->ei_clusters;
 144	if (emi2->ei_cpos >= emi1->ei_cpos && emi2->ei_cpos < range1)
 145		return 1;
 146
 147	/*
 148	 * Check if logical end of emi2 is inside emi1
 149	 */
 150	range2 = emi2->ei_cpos + emi2->ei_clusters;
 151	if (range2 > emi1->ei_cpos && range2 <= range1)
 152		return 1;
 153
 154	return 0;
 155}
 156
 157static void ocfs2_copy_emi_fields(struct ocfs2_extent_map_item *dest,
 158				  struct ocfs2_extent_map_item *src)
 159{
 160	dest->ei_cpos = src->ei_cpos;
 161	dest->ei_phys = src->ei_phys;
 162	dest->ei_clusters = src->ei_clusters;
 163	dest->ei_flags = src->ei_flags;
 164}
 165
 166/*
 167 * Try to merge emi with ins. Returns 1 if merge succeeds, zero
 168 * otherwise.
 169 */
 170static int ocfs2_try_to_merge_extent_map(struct ocfs2_extent_map_item *emi,
 171					 struct ocfs2_extent_map_item *ins)
 172{
 173	/*
 174	 * Handle contiguousness
 175	 */
 176	if (ins->ei_phys == (emi->ei_phys + emi->ei_clusters) &&
 177	    ins->ei_cpos == (emi->ei_cpos + emi->ei_clusters) &&
 178	    ins->ei_flags == emi->ei_flags) {
 179		emi->ei_clusters += ins->ei_clusters;
 180		return 1;
 181	} else if ((ins->ei_phys + ins->ei_clusters) == emi->ei_phys &&
 182		   (ins->ei_cpos + ins->ei_clusters) == emi->ei_cpos &&
 183		   ins->ei_flags == emi->ei_flags) {
 184		emi->ei_phys = ins->ei_phys;
 185		emi->ei_cpos = ins->ei_cpos;
 186		emi->ei_clusters += ins->ei_clusters;
 187		return 1;
 188	}
 189
 190	/*
 191	 * Overlapping extents - this shouldn't happen unless we've
 192	 * split an extent to change it's flags. That is exceedingly
 193	 * rare, so there's no sense in trying to optimize it yet.
 194	 */
 195	if (ocfs2_ei_is_contained(emi, ins) ||
 196	    ocfs2_ei_is_contained(ins, emi)) {
 197		ocfs2_copy_emi_fields(emi, ins);
 198		return 1;
 199	}
 200
 201	/* No merge was possible. */
 202	return 0;
 203}
 204
 205/*
 206 * In order to reduce complexity on the caller, this insert function
 207 * is intentionally liberal in what it will accept.
 208 *
 209 * The only rule is that the truncate call *must* be used whenever
 210 * records have been deleted. This avoids inserting overlapping
 211 * records with different physical mappings.
 212 */
 213void ocfs2_extent_map_insert_rec(struct inode *inode,
 214				 struct ocfs2_extent_rec *rec)
 215{
 216	struct ocfs2_inode_info *oi = OCFS2_I(inode);
 217	struct ocfs2_extent_map *em = &oi->ip_extent_map;
 218	struct ocfs2_extent_map_item *emi, *new_emi = NULL;
 219	struct ocfs2_extent_map_item ins;
 220
 221	ins.ei_cpos = le32_to_cpu(rec->e_cpos);
 222	ins.ei_phys = ocfs2_blocks_to_clusters(inode->i_sb,
 223					       le64_to_cpu(rec->e_blkno));
 224	ins.ei_clusters = le16_to_cpu(rec->e_leaf_clusters);
 225	ins.ei_flags = rec->e_flags;
 226
 227search:
 228	spin_lock(&oi->ip_lock);
 229
 230	list_for_each_entry(emi, &em->em_list, ei_list) {
 231		if (ocfs2_try_to_merge_extent_map(emi, &ins)) {
 232			list_move(&emi->ei_list, &em->em_list);
 233			spin_unlock(&oi->ip_lock);
 234			goto out;
 235		}
 236	}
 237
 238	/*
 239	 * No item could be merged.
 240	 *
 241	 * Either allocate and add a new item, or overwrite the last recently
 242	 * inserted.
 243	 */
 244
 245	if (em->em_num_items < OCFS2_MAX_EXTENT_MAP_ITEMS) {
 246		if (new_emi == NULL) {
 247			spin_unlock(&oi->ip_lock);
 248
 249			new_emi = kmalloc(sizeof(*new_emi), GFP_NOFS);
 250			if (new_emi == NULL)
 251				goto out;
 252
 253			goto search;
 254		}
 255
 256		ocfs2_copy_emi_fields(new_emi, &ins);
 257		list_add(&new_emi->ei_list, &em->em_list);
 258		em->em_num_items++;
 259		new_emi = NULL;
 260	} else {
 261		BUG_ON(list_empty(&em->em_list) || em->em_num_items == 0);
 262		emi = list_entry(em->em_list.prev,
 263				 struct ocfs2_extent_map_item, ei_list);
 264		list_move(&emi->ei_list, &em->em_list);
 265		ocfs2_copy_emi_fields(emi, &ins);
 266	}
 267
 268	spin_unlock(&oi->ip_lock);
 269
 270out:
 271	kfree(new_emi);
 272}
 273
 274static int ocfs2_last_eb_is_empty(struct inode *inode,
 275				  struct ocfs2_dinode *di)
 276{
 277	int ret, next_free;
 278	u64 last_eb_blk = le64_to_cpu(di->i_last_eb_blk);
 279	struct buffer_head *eb_bh = NULL;
 280	struct ocfs2_extent_block *eb;
 281	struct ocfs2_extent_list *el;
 282
 283	ret = ocfs2_read_extent_block(INODE_CACHE(inode), last_eb_blk, &eb_bh);
 284	if (ret) {
 285		mlog_errno(ret);
 286		goto out;
 287	}
 288
 289	eb = (struct ocfs2_extent_block *) eb_bh->b_data;
 290	el = &eb->h_list;
 291
 292	if (el->l_tree_depth) {
 293		ocfs2_error(inode->i_sb,
 294			    "Inode %lu has non zero tree depth in leaf block %llu\n",
 295			    inode->i_ino,
 296			    (unsigned long long)eb_bh->b_blocknr);
 297		ret = -EROFS;
 298		goto out;
 299	}
 300
 301	next_free = le16_to_cpu(el->l_next_free_rec);
 302
 303	if (next_free == 0 ||
 304	    (next_free == 1 && ocfs2_is_empty_extent(&el->l_recs[0])))
 305		ret = 1;
 306
 307out:
 308	brelse(eb_bh);
 309	return ret;
 310}
 311
 312/*
 313 * Return the 1st index within el which contains an extent start
 314 * larger than v_cluster.
 315 */
 316static int ocfs2_search_for_hole_index(struct ocfs2_extent_list *el,
 317				       u32 v_cluster)
 318{
 319	int i;
 320	struct ocfs2_extent_rec *rec;
 321
 322	for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
 323		rec = &el->l_recs[i];
 324
 325		if (v_cluster < le32_to_cpu(rec->e_cpos))
 326			break;
 327	}
 328
 329	return i;
 330}
 331
 332/*
 333 * Figure out the size of a hole which starts at v_cluster within the given
 334 * extent list.
 335 *
 336 * If there is no more allocation past v_cluster, we return the maximum
 337 * cluster size minus v_cluster.
 338 *
 339 * If we have in-inode extents, then el points to the dinode list and
 340 * eb_bh is NULL. Otherwise, eb_bh should point to the extent block
 341 * containing el.
 342 */
 343int ocfs2_figure_hole_clusters(struct ocfs2_caching_info *ci,
 344			       struct ocfs2_extent_list *el,
 345			       struct buffer_head *eb_bh,
 346			       u32 v_cluster,
 347			       u32 *num_clusters)
 348{
 349	int ret, i;
 350	struct buffer_head *next_eb_bh = NULL;
 351	struct ocfs2_extent_block *eb, *next_eb;
 352
 353	i = ocfs2_search_for_hole_index(el, v_cluster);
 354
 355	if (i == le16_to_cpu(el->l_next_free_rec) && eb_bh) {
 356		eb = (struct ocfs2_extent_block *)eb_bh->b_data;
 357
 358		/*
 359		 * Check the next leaf for any extents.
 360		 */
 361
 362		if (le64_to_cpu(eb->h_next_leaf_blk) == 0ULL)
 363			goto no_more_extents;
 364
 365		ret = ocfs2_read_extent_block(ci,
 366					      le64_to_cpu(eb->h_next_leaf_blk),
 367					      &next_eb_bh);
 368		if (ret) {
 369			mlog_errno(ret);
 370			goto out;
 371		}
 372
 373		next_eb = (struct ocfs2_extent_block *)next_eb_bh->b_data;
 374		el = &next_eb->h_list;
 375		i = ocfs2_search_for_hole_index(el, v_cluster);
 376	}
 377
 378no_more_extents:
 379	if (i == le16_to_cpu(el->l_next_free_rec)) {
 380		/*
 381		 * We're at the end of our existing allocation. Just
 382		 * return the maximum number of clusters we could
 383		 * possibly allocate.
 384		 */
 385		*num_clusters = UINT_MAX - v_cluster;
 386	} else {
 387		*num_clusters = le32_to_cpu(el->l_recs[i].e_cpos) - v_cluster;
 388	}
 389
 390	ret = 0;
 391out:
 392	brelse(next_eb_bh);
 393	return ret;
 394}
 395
 396static int ocfs2_get_clusters_nocache(struct inode *inode,
 397				      struct buffer_head *di_bh,
 398				      u32 v_cluster, unsigned int *hole_len,
 399				      struct ocfs2_extent_rec *ret_rec,
 400				      unsigned int *is_last)
 401{
 402	int i, ret, tree_height, len;
 403	struct ocfs2_dinode *di;
 404	struct ocfs2_extent_block *eb;
 405	struct ocfs2_extent_list *el;
 406	struct ocfs2_extent_rec *rec;
 407	struct buffer_head *eb_bh = NULL;
 408
 409	memset(ret_rec, 0, sizeof(*ret_rec));
 410	if (is_last)
 411		*is_last = 0;
 412
 413	di = (struct ocfs2_dinode *) di_bh->b_data;
 414	el = &di->id2.i_list;
 415	tree_height = le16_to_cpu(el->l_tree_depth);
 416
 417	if (tree_height > 0) {
 418		ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
 419				      &eb_bh);
 420		if (ret) {
 421			mlog_errno(ret);
 422			goto out;
 423		}
 424
 425		eb = (struct ocfs2_extent_block *) eb_bh->b_data;
 426		el = &eb->h_list;
 427
 428		if (el->l_tree_depth) {
 429			ocfs2_error(inode->i_sb,
 430				    "Inode %lu has non zero tree depth in leaf block %llu\n",
 431				    inode->i_ino,
 432				    (unsigned long long)eb_bh->b_blocknr);
 433			ret = -EROFS;
 434			goto out;
 435		}
 436	}
 437
 438	i = ocfs2_search_extent_list(el, v_cluster);
 439	if (i == -1) {
 440		/*
 441		 * Holes can be larger than the maximum size of an
 442		 * extent, so we return their lengths in a separate
 443		 * field.
 444		 */
 445		if (hole_len) {
 446			ret = ocfs2_figure_hole_clusters(INODE_CACHE(inode),
 447							 el, eb_bh,
 448							 v_cluster, &len);
 449			if (ret) {
 450				mlog_errno(ret);
 451				goto out;
 452			}
 453
 454			*hole_len = len;
 455		}
 456		goto out_hole;
 457	}
 458
 459	rec = &el->l_recs[i];
 460
 461	BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
 462
 463	if (!rec->e_blkno) {
 464		ocfs2_error(inode->i_sb,
 465			    "Inode %lu has bad extent record (%u, %u, 0)\n",
 466			    inode->i_ino,
 467			    le32_to_cpu(rec->e_cpos),
 468			    ocfs2_rec_clusters(el, rec));
 469		ret = -EROFS;
 470		goto out;
 471	}
 472
 473	*ret_rec = *rec;
 474
 475	/*
 476	 * Checking for last extent is potentially expensive - we
 477	 * might have to look at the next leaf over to see if it's
 478	 * empty.
 479	 *
 480	 * The first two checks are to see whether the caller even
 481	 * cares for this information, and if the extent is at least
 482	 * the last in it's list.
 483	 *
 484	 * If those hold true, then the extent is last if any of the
 485	 * additional conditions hold true:
 486	 *  - Extent list is in-inode
 487	 *  - Extent list is right-most
 488	 *  - Extent list is 2nd to rightmost, with empty right-most
 489	 */
 490	if (is_last) {
 491		if (i == (le16_to_cpu(el->l_next_free_rec) - 1)) {
 492			if (tree_height == 0)
 493				*is_last = 1;
 494			else if (eb->h_blkno == di->i_last_eb_blk)
 495				*is_last = 1;
 496			else if (eb->h_next_leaf_blk == di->i_last_eb_blk) {
 497				ret = ocfs2_last_eb_is_empty(inode, di);
 498				if (ret < 0) {
 499					mlog_errno(ret);
 500					goto out;
 501				}
 502				if (ret == 1)
 503					*is_last = 1;
 504			}
 505		}
 506	}
 507
 508out_hole:
 509	ret = 0;
 510out:
 511	brelse(eb_bh);
 512	return ret;
 513}
 514
 515static void ocfs2_relative_extent_offsets(struct super_block *sb,
 516					  u32 v_cluster,
 517					  struct ocfs2_extent_rec *rec,
 518					  u32 *p_cluster, u32 *num_clusters)
 519
 520{
 521	u32 coff = v_cluster - le32_to_cpu(rec->e_cpos);
 522
 523	*p_cluster = ocfs2_blocks_to_clusters(sb, le64_to_cpu(rec->e_blkno));
 524	*p_cluster = *p_cluster + coff;
 525
 526	if (num_clusters)
 527		*num_clusters = le16_to_cpu(rec->e_leaf_clusters) - coff;
 528}
 529
 530int ocfs2_xattr_get_clusters(struct inode *inode, u32 v_cluster,
 531			     u32 *p_cluster, u32 *num_clusters,
 532			     struct ocfs2_extent_list *el,
 533			     unsigned int *extent_flags)
 534{
 535	int ret = 0, i;
 536	struct buffer_head *eb_bh = NULL;
 537	struct ocfs2_extent_block *eb;
 538	struct ocfs2_extent_rec *rec;
 539	u32 coff;
 540
 541	if (el->l_tree_depth) {
 542		ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
 543				      &eb_bh);
 544		if (ret) {
 545			mlog_errno(ret);
 546			goto out;
 547		}
 548
 549		eb = (struct ocfs2_extent_block *) eb_bh->b_data;
 550		el = &eb->h_list;
 551
 552		if (el->l_tree_depth) {
 553			ocfs2_error(inode->i_sb,
 554				    "Inode %lu has non zero tree depth in xattr leaf block %llu\n",
 555				    inode->i_ino,
 556				    (unsigned long long)eb_bh->b_blocknr);
 557			ret = -EROFS;
 558			goto out;
 559		}
 560	}
 561
 562	i = ocfs2_search_extent_list(el, v_cluster);
 563	if (i == -1) {
 564		ret = -EROFS;
 565		mlog_errno(ret);
 566		goto out;
 567	} else {
 568		rec = &el->l_recs[i];
 569		BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
 570
 571		if (!rec->e_blkno) {
 572			ocfs2_error(inode->i_sb,
 573				    "Inode %lu has bad extent record (%u, %u, 0) in xattr\n",
 574				    inode->i_ino,
 575				    le32_to_cpu(rec->e_cpos),
 576				    ocfs2_rec_clusters(el, rec));
 577			ret = -EROFS;
 578			goto out;
 579		}
 580		coff = v_cluster - le32_to_cpu(rec->e_cpos);
 581		*p_cluster = ocfs2_blocks_to_clusters(inode->i_sb,
 582						    le64_to_cpu(rec->e_blkno));
 583		*p_cluster = *p_cluster + coff;
 584		if (num_clusters)
 585			*num_clusters = ocfs2_rec_clusters(el, rec) - coff;
 586
 587		if (extent_flags)
 588			*extent_flags = rec->e_flags;
 589	}
 590out:
 591	brelse(eb_bh);
 592	return ret;
 593}
 594
 595int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
 596		       u32 *p_cluster, u32 *num_clusters,
 597		       unsigned int *extent_flags)
 598{
 599	int ret;
 600	unsigned int hole_len, flags = 0;
 601	struct buffer_head *di_bh = NULL;
 602	struct ocfs2_extent_rec rec;
 603
 604	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
 605		ret = -ERANGE;
 606		mlog_errno(ret);
 607		goto out;
 608	}
 609
 610	ret = ocfs2_extent_map_lookup(inode, v_cluster, p_cluster,
 611				      num_clusters, extent_flags);
 612	if (ret == 0)
 613		goto out;
 614
 615	ret = ocfs2_read_inode_block(inode, &di_bh);
 616	if (ret) {
 617		mlog_errno(ret);
 618		goto out;
 619	}
 620
 621	ret = ocfs2_get_clusters_nocache(inode, di_bh, v_cluster, &hole_len,
 622					 &rec, NULL);
 623	if (ret) {
 624		mlog_errno(ret);
 625		goto out;
 626	}
 627
 628	if (rec.e_blkno == 0ULL) {
 629		/*
 630		 * A hole was found. Return some canned values that
 631		 * callers can key on. If asked for, num_clusters will
 632		 * be populated with the size of the hole.
 633		 */
 634		*p_cluster = 0;
 635		if (num_clusters) {
 636			*num_clusters = hole_len;
 637		}
 638	} else {
 639		ocfs2_relative_extent_offsets(inode->i_sb, v_cluster, &rec,
 640					      p_cluster, num_clusters);
 641		flags = rec.e_flags;
 642
 643		ocfs2_extent_map_insert_rec(inode, &rec);
 644	}
 645
 646	if (extent_flags)
 647		*extent_flags = flags;
 648
 649out:
 650	brelse(di_bh);
 651	return ret;
 652}
 653
 654/*
 655 * This expects alloc_sem to be held. The allocation cannot change at
 656 * all while the map is in the process of being updated.
 657 */
 658int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno,
 659				u64 *ret_count, unsigned int *extent_flags)
 660{
 661	int ret;
 662	int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
 663	u32 cpos, num_clusters, p_cluster;
 664	u64 boff = 0;
 665
 666	cpos = ocfs2_blocks_to_clusters(inode->i_sb, v_blkno);
 667
 668	ret = ocfs2_get_clusters(inode, cpos, &p_cluster, &num_clusters,
 669				 extent_flags);
 670	if (ret) {
 671		mlog_errno(ret);
 672		goto out;
 673	}
 674
 675	/*
 676	 * p_cluster == 0 indicates a hole.
 677	 */
 678	if (p_cluster) {
 679		boff = ocfs2_clusters_to_blocks(inode->i_sb, p_cluster);
 680		boff += (v_blkno & (u64)(bpc - 1));
 681	}
 682
 683	*p_blkno = boff;
 684
 685	if (ret_count) {
 686		*ret_count = ocfs2_clusters_to_blocks(inode->i_sb, num_clusters);
 687		*ret_count -= v_blkno & (u64)(bpc - 1);
 688	}
 689
 690out:
 691	return ret;
 692}
 693
 694/*
 695 * The ocfs2_fiemap_inline() may be a little bit misleading, since
 696 * it not only handles the fiemap for inlined files, but also deals
 697 * with the fast symlink, cause they have no difference for extent
 698 * mapping per se.
 699 */
 700static int ocfs2_fiemap_inline(struct inode *inode, struct buffer_head *di_bh,
 701			       struct fiemap_extent_info *fieinfo,
 702			       u64 map_start)
 703{
 704	int ret;
 705	unsigned int id_count;
 706	struct ocfs2_dinode *di;
 707	u64 phys;
 708	u32 flags = FIEMAP_EXTENT_DATA_INLINE|FIEMAP_EXTENT_LAST;
 709	struct ocfs2_inode_info *oi = OCFS2_I(inode);
 710
 711	di = (struct ocfs2_dinode *)di_bh->b_data;
 712	if (ocfs2_inode_is_fast_symlink(inode))
 713		id_count = ocfs2_fast_symlink_chars(inode->i_sb);
 714	else
 715		id_count = le16_to_cpu(di->id2.i_data.id_count);
 716
 717	if (map_start < id_count) {
 718		phys = oi->ip_blkno << inode->i_sb->s_blocksize_bits;
 719		if (ocfs2_inode_is_fast_symlink(inode))
 720			phys += offsetof(struct ocfs2_dinode, id2.i_symlink);
 721		else
 722			phys += offsetof(struct ocfs2_dinode,
 723					 id2.i_data.id_data);
 724
 725		ret = fiemap_fill_next_extent(fieinfo, 0, phys, id_count,
 726					      flags);
 727		if (ret < 0)
 728			return ret;
 729	}
 730
 731	return 0;
 732}
 733
 734int ocfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 735		 u64 map_start, u64 map_len)
 736{
 737	int ret, is_last;
 738	u32 mapping_end, cpos;
 739	unsigned int hole_size;
 740	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 741	u64 len_bytes, phys_bytes, virt_bytes;
 742	struct buffer_head *di_bh = NULL;
 743	struct ocfs2_extent_rec rec;
 744
 745	ret = fiemap_prep(inode, fieinfo, map_start, &map_len, 0);
 746	if (ret)
 747		return ret;
 748
 749	ret = ocfs2_inode_lock(inode, &di_bh, 0);
 750	if (ret) {
 751		mlog_errno(ret);
 752		goto out;
 753	}
 754
 755	down_read(&OCFS2_I(inode)->ip_alloc_sem);
 756
 757	/*
 758	 * Handle inline-data and fast symlink separately.
 759	 */
 760	if ((OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) ||
 761	    ocfs2_inode_is_fast_symlink(inode)) {
 762		ret = ocfs2_fiemap_inline(inode, di_bh, fieinfo, map_start);
 763		goto out_unlock;
 764	}
 765
 766	cpos = map_start >> osb->s_clustersize_bits;
 767	mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
 768					       map_start + map_len);
 769	is_last = 0;
 770	while (cpos < mapping_end && !is_last) {
 771		u32 fe_flags;
 772
 773		ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos,
 774						 &hole_size, &rec, &is_last);
 775		if (ret) {
 776			mlog_errno(ret);
 777			goto out_unlock;
 778		}
 779
 780		if (rec.e_blkno == 0ULL) {
 781			cpos += hole_size;
 782			continue;
 783		}
 784
 785		fe_flags = 0;
 786		if (rec.e_flags & OCFS2_EXT_UNWRITTEN)
 787			fe_flags |= FIEMAP_EXTENT_UNWRITTEN;
 788		if (rec.e_flags & OCFS2_EXT_REFCOUNTED)
 789			fe_flags |= FIEMAP_EXTENT_SHARED;
 790		if (is_last)
 791			fe_flags |= FIEMAP_EXTENT_LAST;
 792		len_bytes = (u64)le16_to_cpu(rec.e_leaf_clusters) << osb->s_clustersize_bits;
 793		phys_bytes = le64_to_cpu(rec.e_blkno) << osb->sb->s_blocksize_bits;
 794		virt_bytes = (u64)le32_to_cpu(rec.e_cpos) << osb->s_clustersize_bits;
 795
 796		ret = fiemap_fill_next_extent(fieinfo, virt_bytes, phys_bytes,
 797					      len_bytes, fe_flags);
 798		if (ret)
 799			break;
 800
 801		cpos = le32_to_cpu(rec.e_cpos)+ le16_to_cpu(rec.e_leaf_clusters);
 802	}
 803
 804	if (ret > 0)
 805		ret = 0;
 806
 807out_unlock:
 808	brelse(di_bh);
 809
 810	up_read(&OCFS2_I(inode)->ip_alloc_sem);
 811
 812	ocfs2_inode_unlock(inode, 0);
 813out:
 814
 815	return ret;
 816}
 817
 818/* Is IO overwriting allocated blocks? */
 819int ocfs2_overwrite_io(struct inode *inode, struct buffer_head *di_bh,
 820		       u64 map_start, u64 map_len)
 821{
 822	int ret = 0, is_last;
 823	u32 mapping_end, cpos;
 824	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 825	struct ocfs2_extent_rec rec;
 826
 827	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
 828		if (ocfs2_size_fits_inline_data(di_bh, map_start + map_len))
 829			return ret;
 830		else
 831			return -EAGAIN;
 832	}
 833
 834	cpos = map_start >> osb->s_clustersize_bits;
 835	mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
 836					       map_start + map_len);
 837	is_last = 0;
 838	while (cpos < mapping_end && !is_last) {
 839		ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos,
 840						 NULL, &rec, &is_last);
 841		if (ret) {
 842			mlog_errno(ret);
 843			goto out;
 844		}
 845
 846		if (rec.e_blkno == 0ULL)
 847			break;
 848
 849		if (rec.e_flags & OCFS2_EXT_REFCOUNTED)
 850			break;
 851
 852		cpos = le32_to_cpu(rec.e_cpos) +
 853			le16_to_cpu(rec.e_leaf_clusters);
 854	}
 855
 856	if (cpos < mapping_end)
 857		ret = -EAGAIN;
 858out:
 859	return ret;
 860}
 861
 862int ocfs2_seek_data_hole_offset(struct file *file, loff_t *offset, int whence)
 863{
 864	struct inode *inode = file->f_mapping->host;
 865	int ret;
 866	unsigned int is_last = 0, is_data = 0;
 867	u16 cs_bits = OCFS2_SB(inode->i_sb)->s_clustersize_bits;
 868	u32 cpos, cend, clen, hole_size;
 869	u64 extoff, extlen;
 870	struct buffer_head *di_bh = NULL;
 871	struct ocfs2_extent_rec rec;
 872
 873	BUG_ON(whence != SEEK_DATA && whence != SEEK_HOLE);
 874
 875	ret = ocfs2_inode_lock(inode, &di_bh, 0);
 876	if (ret) {
 877		mlog_errno(ret);
 878		goto out;
 879	}
 880
 881	down_read(&OCFS2_I(inode)->ip_alloc_sem);
 882
 883	if (*offset >= i_size_read(inode)) {
 884		ret = -ENXIO;
 885		goto out_unlock;
 886	}
 887
 888	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
 889		if (whence == SEEK_HOLE)
 890			*offset = i_size_read(inode);
 891		goto out_unlock;
 892	}
 893
 894	clen = 0;
 895	cpos = *offset >> cs_bits;
 896	cend = ocfs2_clusters_for_bytes(inode->i_sb, i_size_read(inode));
 897
 898	while (cpos < cend && !is_last) {
 899		ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos, &hole_size,
 900						 &rec, &is_last);
 901		if (ret) {
 902			mlog_errno(ret);
 903			goto out_unlock;
 904		}
 905
 906		extoff = cpos;
 907		extoff <<= cs_bits;
 908
 909		if (rec.e_blkno == 0ULL) {
 910			clen = hole_size;
 911			is_data = 0;
 912		} else {
 913			clen = le16_to_cpu(rec.e_leaf_clusters) -
 914				(cpos - le32_to_cpu(rec.e_cpos));
 915			is_data = (rec.e_flags & OCFS2_EXT_UNWRITTEN) ?  0 : 1;
 916		}
 917
 918		if ((!is_data && whence == SEEK_HOLE) ||
 919		    (is_data && whence == SEEK_DATA)) {
 920			if (extoff > *offset)
 921				*offset = extoff;
 922			goto out_unlock;
 923		}
 924
 925		if (!is_last)
 926			cpos += clen;
 927	}
 928
 929	if (whence == SEEK_HOLE) {
 930		extoff = cpos;
 931		extoff <<= cs_bits;
 932		extlen = clen;
 933		extlen <<=  cs_bits;
 934
 935		if ((extoff + extlen) > i_size_read(inode))
 936			extlen = i_size_read(inode) - extoff;
 937		extoff += extlen;
 938		if (extoff > *offset)
 939			*offset = extoff;
 940		goto out_unlock;
 941	}
 942
 943	ret = -ENXIO;
 944
 945out_unlock:
 946
 947	brelse(di_bh);
 948
 949	up_read(&OCFS2_I(inode)->ip_alloc_sem);
 950
 951	ocfs2_inode_unlock(inode, 0);
 952out:
 953	return ret;
 954}
 955
 956int ocfs2_read_virt_blocks(struct inode *inode, u64 v_block, int nr,
 957			   struct buffer_head *bhs[], int flags,
 958			   int (*validate)(struct super_block *sb,
 959					   struct buffer_head *bh))
 960{
 961	int rc = 0;
 962	u64 p_block, p_count;
 963	int i, count, done = 0;
 964
 965	trace_ocfs2_read_virt_blocks(
 966	     inode, (unsigned long long)v_block, nr, bhs, flags,
 967	     validate);
 968
 969	if (((v_block + nr - 1) << inode->i_sb->s_blocksize_bits) >=
 970	    i_size_read(inode)) {
 971		BUG_ON(!(flags & OCFS2_BH_READAHEAD));
 972		goto out;
 973	}
 974
 975	while (done < nr) {
 976		down_read(&OCFS2_I(inode)->ip_alloc_sem);
 977		rc = ocfs2_extent_map_get_blocks(inode, v_block + done,
 978						 &p_block, &p_count, NULL);
 979		up_read(&OCFS2_I(inode)->ip_alloc_sem);
 980		if (rc) {
 981			mlog_errno(rc);
 982			break;
 983		}
 984
 985		if (!p_block) {
 986			rc = -EIO;
 987			mlog(ML_ERROR,
 988			     "Inode #%llu contains a hole at offset %llu\n",
 989			     (unsigned long long)OCFS2_I(inode)->ip_blkno,
 990			     (unsigned long long)(v_block + done) <<
 991			     inode->i_sb->s_blocksize_bits);
 992			break;
 993		}
 994
 995		count = nr - done;
 996		if (p_count < count)
 997			count = p_count;
 998
 999		/*
1000		 * If the caller passed us bhs, they should have come
1001		 * from a previous readahead call to this function.  Thus,
1002		 * they should have the right b_blocknr.
1003		 */
1004		for (i = 0; i < count; i++) {
1005			if (!bhs[done + i])
1006				continue;
1007			BUG_ON(bhs[done + i]->b_blocknr != (p_block + i));
1008		}
1009
1010		rc = ocfs2_read_blocks(INODE_CACHE(inode), p_block, count,
1011				       bhs + done, flags, validate);
1012		if (rc) {
1013			mlog_errno(rc);
1014			break;
1015		}
1016		done += count;
1017	}
1018
1019out:
1020	return rc;
1021}
1022
1023