1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (C) 2007 Oracle.  All rights reserved.
   4 */
   5
   6#include <linux/bio.h>
   7#include <linux/slab.h>
   8#include <linux/pagemap.h>
   9#include <linux/highmem.h>
  10#include <linux/sched/mm.h>
  11#include <crypto/hash.h>
  12#include "messages.h"
  13#include "misc.h"
  14#include "ctree.h"
  15#include "disk-io.h"
  16#include "transaction.h"
  17#include "bio.h"
  18#include "print-tree.h"
  19#include "compression.h"
  20#include "fs.h"
  21#include "accessors.h"
  22#include "file-item.h"
  23#include "super.h"
  24
  25#define __MAX_CSUM_ITEMS(r, size) ((unsigned long)(((BTRFS_LEAF_DATA_SIZE(r) - \
  26				   sizeof(struct btrfs_item) * 2) / \
  27				  size) - 1))
  28
  29#define MAX_CSUM_ITEMS(r, size) (min_t(u32, __MAX_CSUM_ITEMS(r, size), \
  30				       PAGE_SIZE))
  31
  32/*
  33 * Set inode's size according to filesystem options.
  34 *
  35 * @inode:      inode we want to update the disk_i_size for
  36 * @new_i_size: i_size we want to set to, 0 if we use i_size
  37 *
  38 * With NO_HOLES set this simply sets the disk_is_size to whatever i_size_read()
  39 * returns as it is perfectly fine with a file that has holes without hole file
  40 * extent items.
  41 *
  42 * However without NO_HOLES we need to only return the area that is contiguous
  43 * from the 0 offset of the file.  Otherwise we could end up adjust i_size up
  44 * to an extent that has a gap in between.
  45 *
  46 * Finally new_i_size should only be set in the case of truncate where we're not
  47 * ready to use i_size_read() as the limiter yet.
  48 */
  49void btrfs_inode_safe_disk_i_size_write(struct btrfs_inode *inode, u64 new_i_size)
  50{
  51	struct btrfs_fs_info *fs_info = inode->root->fs_info;
  52	u64 start, end, i_size;
  53	int ret;
  54
  55	spin_lock(&inode->lock);
  56	i_size = new_i_size ?: i_size_read(&inode->vfs_inode);
  57	if (btrfs_fs_incompat(fs_info, NO_HOLES)) {
  58		inode->disk_i_size = i_size;
  59		goto out_unlock;
  60	}
  61
  62	ret = find_contiguous_extent_bit(inode->file_extent_tree, 0, &start,
  63					 &end, EXTENT_DIRTY);
  64	if (!ret && start == 0)
  65		i_size = min(i_size, end + 1);
  66	else
  67		i_size = 0;
  68	inode->disk_i_size = i_size;
  69out_unlock:
  70	spin_unlock(&inode->lock);
  71}
  72
  73/*
  74 * Mark range within a file as having a new extent inserted.
  75 *
  76 * @inode: inode being modified
  77 * @start: start file offset of the file extent we've inserted
  78 * @len:   logical length of the file extent item
  79 *
  80 * Call when we are inserting a new file extent where there was none before.
  81 * Does not need to call this in the case where we're replacing an existing file
  82 * extent, however if not sure it's fine to call this multiple times.
  83 *
  84 * The start and len must match the file extent item, so thus must be sectorsize
  85 * aligned.
  86 */
  87int btrfs_inode_set_file_extent_range(struct btrfs_inode *inode, u64 start,
  88				      u64 len)
  89{
  90	if (len == 0)
  91		return 0;
  92
  93	ASSERT(IS_ALIGNED(start + len, inode->root->fs_info->sectorsize));
  94
  95	if (btrfs_fs_incompat(inode->root->fs_info, NO_HOLES))
  96		return 0;
  97	return set_extent_bit(inode->file_extent_tree, start, start + len - 1,
  98			      EXTENT_DIRTY, NULL);
  99}
 100
 101/*
 102 * Mark an inode range as not having a backing extent.
 103 *
 104 * @inode: inode being modified
 105 * @start: start file offset of the file extent we've inserted
 106 * @len:   logical length of the file extent item
 107 *
 108 * Called when we drop a file extent, for example when we truncate.  Doesn't
 109 * need to be called for cases where we're replacing a file extent, like when
 110 * we've COWed a file extent.
 111 *
 112 * The start and len must match the file extent item, so thus must be sectorsize
 113 * aligned.
 114 */
 115int btrfs_inode_clear_file_extent_range(struct btrfs_inode *inode, u64 start,
 116					u64 len)
 117{
 118	if (len == 0)
 119		return 0;
 120
 121	ASSERT(IS_ALIGNED(start + len, inode->root->fs_info->sectorsize) ||
 122	       len == (u64)-1);
 123
 124	if (btrfs_fs_incompat(inode->root->fs_info, NO_HOLES))
 125		return 0;
 126	return clear_extent_bit(inode->file_extent_tree, start,
 127				start + len - 1, EXTENT_DIRTY, NULL);
 128}
 129
 130static size_t bytes_to_csum_size(const struct btrfs_fs_info *fs_info, u32 bytes)
 131{
 132	ASSERT(IS_ALIGNED(bytes, fs_info->sectorsize));
 133
 134	return (bytes >> fs_info->sectorsize_bits) * fs_info->csum_size;
 135}
 136
 137static size_t csum_size_to_bytes(const struct btrfs_fs_info *fs_info, u32 csum_size)
 138{
 139	ASSERT(IS_ALIGNED(csum_size, fs_info->csum_size));
 140
 141	return (csum_size / fs_info->csum_size) << fs_info->sectorsize_bits;
 142}
 143
 144static inline u32 max_ordered_sum_bytes(const struct btrfs_fs_info *fs_info)
 145{
 146	u32 max_csum_size = round_down(PAGE_SIZE - sizeof(struct btrfs_ordered_sum),
 147				       fs_info->csum_size);
 148
 149	return csum_size_to_bytes(fs_info, max_csum_size);
 150}
 151
 152/*
 153 * Calculate the total size needed to allocate for an ordered sum structure
 154 * spanning @bytes in the file.
 155 */
 156static int btrfs_ordered_sum_size(struct btrfs_fs_info *fs_info, unsigned long bytes)
 157{
 158	return sizeof(struct btrfs_ordered_sum) + bytes_to_csum_size(fs_info, bytes);
 159}
 160
 161int btrfs_insert_hole_extent(struct btrfs_trans_handle *trans,
 162			     struct btrfs_root *root,
 163			     u64 objectid, u64 pos, u64 num_bytes)
 164{
 165	int ret = 0;
 166	struct btrfs_file_extent_item *item;
 167	struct btrfs_key file_key;
 168	struct btrfs_path *path;
 169	struct extent_buffer *leaf;
 170
 171	path = btrfs_alloc_path();
 172	if (!path)
 173		return -ENOMEM;
 174	file_key.objectid = objectid;
 175	file_key.offset = pos;
 176	file_key.type = BTRFS_EXTENT_DATA_KEY;
 177
 178	ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 179				      sizeof(*item));
 180	if (ret < 0)
 181		goto out;
 182	BUG_ON(ret); /* Can't happen */
 183	leaf = path->nodes[0];
 184	item = btrfs_item_ptr(leaf, path->slots[0],
 185			      struct btrfs_file_extent_item);
 186	btrfs_set_file_extent_disk_bytenr(leaf, item, 0);
 187	btrfs_set_file_extent_disk_num_bytes(leaf, item, 0);
 188	btrfs_set_file_extent_offset(leaf, item, 0);
 189	btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
 190	btrfs_set_file_extent_ram_bytes(leaf, item, num_bytes);
 191	btrfs_set_file_extent_generation(leaf, item, trans->transid);
 192	btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
 193	btrfs_set_file_extent_compression(leaf, item, 0);
 194	btrfs_set_file_extent_encryption(leaf, item, 0);
 195	btrfs_set_file_extent_other_encoding(leaf, item, 0);
 196
 197	btrfs_mark_buffer_dirty(trans, leaf);
 198out:
 199	btrfs_free_path(path);
 200	return ret;
 201}
 202
 203static struct btrfs_csum_item *
 204btrfs_lookup_csum(struct btrfs_trans_handle *trans,
 205		  struct btrfs_root *root,
 206		  struct btrfs_path *path,
 207		  u64 bytenr, int cow)
 208{
 209	struct btrfs_fs_info *fs_info = root->fs_info;
 210	int ret;
 211	struct btrfs_key file_key;
 212	struct btrfs_key found_key;
 213	struct btrfs_csum_item *item;
 214	struct extent_buffer *leaf;
 215	u64 csum_offset = 0;
 216	const u32 csum_size = fs_info->csum_size;
 217	int csums_in_item;
 218
 219	file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 220	file_key.offset = bytenr;
 221	file_key.type = BTRFS_EXTENT_CSUM_KEY;
 222	ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
 223	if (ret < 0)
 224		goto fail;
 225	leaf = path->nodes[0];
 226	if (ret > 0) {
 227		ret = 1;
 228		if (path->slots[0] == 0)
 229			goto fail;
 230		path->slots[0]--;
 231		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 232		if (found_key.type != BTRFS_EXTENT_CSUM_KEY)
 233			goto fail;
 234
 235		csum_offset = (bytenr - found_key.offset) >>
 236				fs_info->sectorsize_bits;
 237		csums_in_item = btrfs_item_size(leaf, path->slots[0]);
 238		csums_in_item /= csum_size;
 239
 240		if (csum_offset == csums_in_item) {
 241			ret = -EFBIG;
 242			goto fail;
 243		} else if (csum_offset > csums_in_item) {
 244			goto fail;
 245		}
 246	}
 247	item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 248	item = (struct btrfs_csum_item *)((unsigned char *)item +
 249					  csum_offset * csum_size);
 250	return item;
 251fail:
 252	if (ret > 0)
 253		ret = -ENOENT;
 254	return ERR_PTR(ret);
 255}
 256
 257int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
 258			     struct btrfs_root *root,
 259			     struct btrfs_path *path, u64 objectid,
 260			     u64 offset, int mod)
 261{
 262	struct btrfs_key file_key;
 263	int ins_len = mod < 0 ? -1 : 0;
 264	int cow = mod != 0;
 265
 266	file_key.objectid = objectid;
 267	file_key.offset = offset;
 268	file_key.type = BTRFS_EXTENT_DATA_KEY;
 269
 270	return btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
 271}
 272
 273/*
 274 * Find checksums for logical bytenr range [disk_bytenr, disk_bytenr + len) and
 275 * store the result to @dst.
 276 *
 277 * Return >0 for the number of sectors we found.
 278 * Return 0 for the range [disk_bytenr, disk_bytenr + sectorsize) has no csum
 279 * for it. Caller may want to try next sector until one range is hit.
 280 * Return <0 for fatal error.
 281 */
 282static int search_csum_tree(struct btrfs_fs_info *fs_info,
 283			    struct btrfs_path *path, u64 disk_bytenr,
 284			    u64 len, u8 *dst)
 285{
 286	struct btrfs_root *csum_root;
 287	struct btrfs_csum_item *item = NULL;
 288	struct btrfs_key key;
 289	const u32 sectorsize = fs_info->sectorsize;
 290	const u32 csum_size = fs_info->csum_size;
 291	u32 itemsize;
 292	int ret;
 293	u64 csum_start;
 294	u64 csum_len;
 295
 296	ASSERT(IS_ALIGNED(disk_bytenr, sectorsize) &&
 297	       IS_ALIGNED(len, sectorsize));
 298
 299	/* Check if the current csum item covers disk_bytenr */
 300	if (path->nodes[0]) {
 301		item = btrfs_item_ptr(path->nodes[0], path->slots[0],
 302				      struct btrfs_csum_item);
 303		btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 304		itemsize = btrfs_item_size(path->nodes[0], path->slots[0]);
 305
 306		csum_start = key.offset;
 307		csum_len = (itemsize / csum_size) * sectorsize;
 308
 309		if (in_range(disk_bytenr, csum_start, csum_len))
 310			goto found;
 311	}
 312
 313	/* Current item doesn't contain the desired range, search again */
 314	btrfs_release_path(path);
 315	csum_root = btrfs_csum_root(fs_info, disk_bytenr);
 316	item = btrfs_lookup_csum(NULL, csum_root, path, disk_bytenr, 0);
 317	if (IS_ERR(item)) {
 318		ret = PTR_ERR(item);
 319		goto out;
 320	}
 321	btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 322	itemsize = btrfs_item_size(path->nodes[0], path->slots[0]);
 323
 324	csum_start = key.offset;
 325	csum_len = (itemsize / csum_size) * sectorsize;
 326	ASSERT(in_range(disk_bytenr, csum_start, csum_len));
 327
 328found:
 329	ret = (min(csum_start + csum_len, disk_bytenr + len) -
 330		   disk_bytenr) >> fs_info->sectorsize_bits;
 331	read_extent_buffer(path->nodes[0], dst, (unsigned long)item,
 332			ret * csum_size);
 333out:
 334	if (ret == -ENOENT || ret == -EFBIG)
 335		ret = 0;
 336	return ret;
 337}
 338
 339/*
 340 * Lookup the checksum for the read bio in csum tree.
 341 *
 342 * Return: BLK_STS_RESOURCE if allocating memory fails, BLK_STS_OK otherwise.
 343 */
 344blk_status_t btrfs_lookup_bio_sums(struct btrfs_bio *bbio)
 345{
 346	struct btrfs_inode *inode = bbio->inode;
 347	struct btrfs_fs_info *fs_info = inode->root->fs_info;
 348	struct bio *bio = &bbio->bio;
 349	struct btrfs_path *path;
 350	const u32 sectorsize = fs_info->sectorsize;
 351	const u32 csum_size = fs_info->csum_size;
 352	u32 orig_len = bio->bi_iter.bi_size;
 353	u64 orig_disk_bytenr = bio->bi_iter.bi_sector << SECTOR_SHIFT;
 354	const unsigned int nblocks = orig_len >> fs_info->sectorsize_bits;
 355	blk_status_t ret = BLK_STS_OK;
 356	u32 bio_offset = 0;
 357
 358	if ((inode->flags & BTRFS_INODE_NODATASUM) ||
 359	    test_bit(BTRFS_FS_STATE_NO_CSUMS, &fs_info->fs_state))
 360		return BLK_STS_OK;
 361
 362	/*
 363	 * This function is only called for read bio.
 364	 *
 365	 * This means two things:
 366	 * - All our csums should only be in csum tree
 367	 *   No ordered extents csums, as ordered extents are only for write
 368	 *   path.
 369	 * - No need to bother any other info from bvec
 370	 *   Since we're looking up csums, the only important info is the
 371	 *   disk_bytenr and the length, which can be extracted from bi_iter
 372	 *   directly.
 373	 */
 374	ASSERT(bio_op(bio) == REQ_OP_READ);
 375	path = btrfs_alloc_path();
 376	if (!path)
 377		return BLK_STS_RESOURCE;
 378
 379	if (nblocks * csum_size > BTRFS_BIO_INLINE_CSUM_SIZE) {
 380		bbio->csum = kmalloc_array(nblocks, csum_size, GFP_NOFS);
 381		if (!bbio->csum) {
 382			btrfs_free_path(path);
 383			return BLK_STS_RESOURCE;
 384		}
 385	} else {
 386		bbio->csum = bbio->csum_inline;
 387	}
 388
 389	/*
 390	 * If requested number of sectors is larger than one leaf can contain,
 391	 * kick the readahead for csum tree.
 392	 */
 393	if (nblocks > fs_info->csums_per_leaf)
 394		path->reada = READA_FORWARD;
 395
 396	/*
 397	 * the free space stuff is only read when it hasn't been
 398	 * updated in the current transaction.  So, we can safely
 399	 * read from the commit root and sidestep a nasty deadlock
 400	 * between reading the free space cache and updating the csum tree.
 401	 */
 402	if (btrfs_is_free_space_inode(inode)) {
 403		path->search_commit_root = 1;
 404		path->skip_locking = 1;
 405	}
 406
 407	while (bio_offset < orig_len) {
 408		int count;
 409		u64 cur_disk_bytenr = orig_disk_bytenr + bio_offset;
 410		u8 *csum_dst = bbio->csum +
 411			(bio_offset >> fs_info->sectorsize_bits) * csum_size;
 412
 413		count = search_csum_tree(fs_info, path, cur_disk_bytenr,
 414					 orig_len - bio_offset, csum_dst);
 415		if (count < 0) {
 416			ret = errno_to_blk_status(count);
 417			if (bbio->csum != bbio->csum_inline)
 418				kfree(bbio->csum);
 419			bbio->csum = NULL;
 420			break;
 421		}
 422
 423		/*
 424		 * We didn't find a csum for this range.  We need to make sure
 425		 * we complain loudly about this, because we are not NODATASUM.
 426		 *
 427		 * However for the DATA_RELOC inode we could potentially be
 428		 * relocating data extents for a NODATASUM inode, so the inode
 429		 * itself won't be marked with NODATASUM, but the extent we're
 430		 * copying is in fact NODATASUM.  If we don't find a csum we
 431		 * assume this is the case.
 432		 */
 433		if (count == 0) {
 434			memset(csum_dst, 0, csum_size);
 435			count = 1;
 436
 437			if (inode->root->root_key.objectid ==
 438			    BTRFS_DATA_RELOC_TREE_OBJECTID) {
 439				u64 file_offset = bbio->file_offset + bio_offset;
 440
 441				set_extent_bit(&inode->io_tree, file_offset,
 442					       file_offset + sectorsize - 1,
 443					       EXTENT_NODATASUM, NULL);
 444			} else {
 445				btrfs_warn_rl(fs_info,
 446			"csum hole found for disk bytenr range [%llu, %llu)",
 447				cur_disk_bytenr, cur_disk_bytenr + sectorsize);
 448			}
 449		}
 450		bio_offset += count * sectorsize;
 451	}
 452
 453	btrfs_free_path(path);
 454	return ret;
 455}
 456
 457int btrfs_lookup_csums_list(struct btrfs_root *root, u64 start, u64 end,
 458			    struct list_head *list, int search_commit,
 459			    bool nowait)
 460{
 461	struct btrfs_fs_info *fs_info = root->fs_info;
 462	struct btrfs_key key;
 463	struct btrfs_path *path;
 464	struct extent_buffer *leaf;
 465	struct btrfs_ordered_sum *sums;
 466	struct btrfs_csum_item *item;
 467	LIST_HEAD(tmplist);
 468	int ret;
 469
 470	ASSERT(IS_ALIGNED(start, fs_info->sectorsize) &&
 471	       IS_ALIGNED(end + 1, fs_info->sectorsize));
 472
 473	path = btrfs_alloc_path();
 474	if (!path)
 475		return -ENOMEM;
 476
 477	path->nowait = nowait;
 478	if (search_commit) {
 479		path->skip_locking = 1;
 480		path->reada = READA_FORWARD;
 481		path->search_commit_root = 1;
 482	}
 483
 484	key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 485	key.offset = start;
 486	key.type = BTRFS_EXTENT_CSUM_KEY;
 487
 488	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 489	if (ret < 0)
 490		goto fail;
 491	if (ret > 0 && path->slots[0] > 0) {
 492		leaf = path->nodes[0];
 493		btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
 494
 495		/*
 496		 * There are two cases we can hit here for the previous csum
 497		 * item:
 498		 *
 499		 *		|<- search range ->|
 500		 *	|<- csum item ->|
 501		 *
 502		 * Or
 503		 *				|<- search range ->|
 504		 *	|<- csum item ->|
 505		 *
 506		 * Check if the previous csum item covers the leading part of
 507		 * the search range.  If so we have to start from previous csum
 508		 * item.
 509		 */
 510		if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
 511		    key.type == BTRFS_EXTENT_CSUM_KEY) {
 512			if (bytes_to_csum_size(fs_info, start - key.offset) <
 513			    btrfs_item_size(leaf, path->slots[0] - 1))
 514				path->slots[0]--;
 515		}
 516	}
 517
 518	while (start <= end) {
 519		u64 csum_end;
 520
 521		leaf = path->nodes[0];
 522		if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 523			ret = btrfs_next_leaf(root, path);
 524			if (ret < 0)
 525				goto fail;
 526			if (ret > 0)
 527				break;
 528			leaf = path->nodes[0];
 529		}
 530
 531		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 532		if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 533		    key.type != BTRFS_EXTENT_CSUM_KEY ||
 534		    key.offset > end)
 535			break;
 536
 537		if (key.offset > start)
 538			start = key.offset;
 539
 540		csum_end = key.offset + csum_size_to_bytes(fs_info,
 541					btrfs_item_size(leaf, path->slots[0]));
 542		if (csum_end <= start) {
 543			path->slots[0]++;
 544			continue;
 545		}
 546
 547		csum_end = min(csum_end, end + 1);
 548		item = btrfs_item_ptr(path->nodes[0], path->slots[0],
 549				      struct btrfs_csum_item);
 550		while (start < csum_end) {
 551			unsigned long offset;
 552			size_t size;
 553
 554			size = min_t(size_t, csum_end - start,
 555				     max_ordered_sum_bytes(fs_info));
 556			sums = kzalloc(btrfs_ordered_sum_size(fs_info, size),
 557				       GFP_NOFS);
 558			if (!sums) {
 559				ret = -ENOMEM;
 560				goto fail;
 561			}
 562
 563			sums->logical = start;
 564			sums->len = size;
 565
 566			offset = bytes_to_csum_size(fs_info, start - key.offset);
 567
 568			read_extent_buffer(path->nodes[0],
 569					   sums->sums,
 570					   ((unsigned long)item) + offset,
 571					   bytes_to_csum_size(fs_info, size));
 572
 573			start += size;
 574			list_add_tail(&sums->list, &tmplist);
 575		}
 576		path->slots[0]++;
 577	}
 578	ret = 0;
 579fail:
 580	while (ret < 0 && !list_empty(&tmplist)) {
 581		sums = list_entry(tmplist.next, struct btrfs_ordered_sum, list);
 582		list_del(&sums->list);
 583		kfree(sums);
 584	}
 585	list_splice_tail(&tmplist, list);
 586
 587	btrfs_free_path(path);
 588	return ret;
 589}
 590
 591/*
 592 * Do the same work as btrfs_lookup_csums_list(), the difference is in how
 593 * we return the result.
 594 *
 595 * This version will set the corresponding bits in @csum_bitmap to represent
 596 * that there is a csum found.
 597 * Each bit represents a sector. Thus caller should ensure @csum_buf passed
 598 * in is large enough to contain all csums.
 599 */
 600int btrfs_lookup_csums_bitmap(struct btrfs_root *root, struct btrfs_path *path,
 601			      u64 start, u64 end, u8 *csum_buf,
 602			      unsigned long *csum_bitmap)
 603{
 604	struct btrfs_fs_info *fs_info = root->fs_info;
 605	struct btrfs_key key;
 606	struct extent_buffer *leaf;
 607	struct btrfs_csum_item *item;
 608	const u64 orig_start = start;
 609	bool free_path = false;
 610	int ret;
 611
 612	ASSERT(IS_ALIGNED(start, fs_info->sectorsize) &&
 613	       IS_ALIGNED(end + 1, fs_info->sectorsize));
 614
 615	if (!path) {
 616		path = btrfs_alloc_path();
 617		if (!path)
 618			return -ENOMEM;
 619		free_path = true;
 620	}
 621
 622	/* Check if we can reuse the previous path. */
 623	if (path->nodes[0]) {
 624		btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 625
 626		if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
 627		    key.type == BTRFS_EXTENT_CSUM_KEY &&
 628		    key.offset <= start)
 629			goto search_forward;
 630		btrfs_release_path(path);
 631	}
 632
 633	key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 634	key.type = BTRFS_EXTENT_CSUM_KEY;
 635	key.offset = start;
 636
 637	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 638	if (ret < 0)
 639		goto fail;
 640	if (ret > 0 && path->slots[0] > 0) {
 641		leaf = path->nodes[0];
 642		btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
 643
 644		/*
 645		 * There are two cases we can hit here for the previous csum
 646		 * item:
 647		 *
 648		 *		|<- search range ->|
 649		 *	|<- csum item ->|
 650		 *
 651		 * Or
 652		 *				|<- search range ->|
 653		 *	|<- csum item ->|
 654		 *
 655		 * Check if the previous csum item covers the leading part of
 656		 * the search range.  If so we have to start from previous csum
 657		 * item.
 658		 */
 659		if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
 660		    key.type == BTRFS_EXTENT_CSUM_KEY) {
 661			if (bytes_to_csum_size(fs_info, start - key.offset) <
 662			    btrfs_item_size(leaf, path->slots[0] - 1))
 663				path->slots[0]--;
 664		}
 665	}
 666
 667search_forward:
 668	while (start <= end) {
 669		u64 csum_end;
 670
 671		leaf = path->nodes[0];
 672		if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 673			ret = btrfs_next_leaf(root, path);
 674			if (ret < 0)
 675				goto fail;
 676			if (ret > 0)
 677				break;
 678			leaf = path->nodes[0];
 679		}
 680
 681		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 682		if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 683		    key.type != BTRFS_EXTENT_CSUM_KEY ||
 684		    key.offset > end)
 685			break;
 686
 687		if (key.offset > start)
 688			start = key.offset;
 689
 690		csum_end = key.offset + csum_size_to_bytes(fs_info,
 691					btrfs_item_size(leaf, path->slots[0]));
 692		if (csum_end <= start) {
 693			path->slots[0]++;
 694			continue;
 695		}
 696
 697		csum_end = min(csum_end, end + 1);
 698		item = btrfs_item_ptr(path->nodes[0], path->slots[0],
 699				      struct btrfs_csum_item);
 700		while (start < csum_end) {
 701			unsigned long offset;
 702			size_t size;
 703			u8 *csum_dest = csum_buf + bytes_to_csum_size(fs_info,
 704						start - orig_start);
 705
 706			size = min_t(size_t, csum_end - start, end + 1 - start);
 707
 708			offset = bytes_to_csum_size(fs_info, start - key.offset);
 709
 710			read_extent_buffer(path->nodes[0], csum_dest,
 711					   ((unsigned long)item) + offset,
 712					   bytes_to_csum_size(fs_info, size));
 713
 714			bitmap_set(csum_bitmap,
 715				(start - orig_start) >> fs_info->sectorsize_bits,
 716				size >> fs_info->sectorsize_bits);
 717
 718			start += size;
 719		}
 720		path->slots[0]++;
 721	}
 722	ret = 0;
 723fail:
 724	if (free_path)
 725		btrfs_free_path(path);
 726	return ret;
 727}
 728
 729/*
 730 * Calculate checksums of the data contained inside a bio.
 731 */
 732blk_status_t btrfs_csum_one_bio(struct btrfs_bio *bbio)
 733{
 734	struct btrfs_ordered_extent *ordered = bbio->ordered;
 735	struct btrfs_inode *inode = bbio->inode;
 736	struct btrfs_fs_info *fs_info = inode->root->fs_info;
 737	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
 738	struct bio *bio = &bbio->bio;
 739	struct btrfs_ordered_sum *sums;
 740	char *data;
 741	struct bvec_iter iter;
 742	struct bio_vec bvec;
 743	int index;
 744	unsigned int blockcount;
 745	int i;
 746	unsigned nofs_flag;
 747
 748	nofs_flag = memalloc_nofs_save();
 749	sums = kvzalloc(btrfs_ordered_sum_size(fs_info, bio->bi_iter.bi_size),
 750		       GFP_KERNEL);
 751	memalloc_nofs_restore(nofs_flag);
 752
 753	if (!sums)
 754		return BLK_STS_RESOURCE;
 755
 756	sums->len = bio->bi_iter.bi_size;
 757	INIT_LIST_HEAD(&sums->list);
 758
 759	sums->logical = bio->bi_iter.bi_sector << SECTOR_SHIFT;
 760	index = 0;
 761
 762	shash->tfm = fs_info->csum_shash;
 763
 764	bio_for_each_segment(bvec, bio, iter) {
 765		blockcount = BTRFS_BYTES_TO_BLKS(fs_info,
 766						 bvec.bv_len + fs_info->sectorsize
 767						 - 1);
 768
 769		for (i = 0; i < blockcount; i++) {
 770			data = bvec_kmap_local(&bvec);
 771			crypto_shash_digest(shash,
 772					    data + (i * fs_info->sectorsize),
 773					    fs_info->sectorsize,
 774					    sums->sums + index);
 775			kunmap_local(data);
 776			index += fs_info->csum_size;
 777		}
 778
 779	}
 780
 781	bbio->sums = sums;
 782	btrfs_add_ordered_sum(ordered, sums);
 783	return 0;
 784}
 785
 786/*
 787 * Nodatasum I/O on zoned file systems still requires an btrfs_ordered_sum to
 788 * record the updated logical address on Zone Append completion.
 789 * Allocate just the structure with an empty sums array here for that case.
 790 */
 791blk_status_t btrfs_alloc_dummy_sum(struct btrfs_bio *bbio)
 792{
 793	bbio->sums = kmalloc(sizeof(*bbio->sums), GFP_NOFS);
 794	if (!bbio->sums)
 795		return BLK_STS_RESOURCE;
 796	bbio->sums->len = bbio->bio.bi_iter.bi_size;
 797	bbio->sums->logical = bbio->bio.bi_iter.bi_sector << SECTOR_SHIFT;
 798	btrfs_add_ordered_sum(bbio->ordered, bbio->sums);
 799	return 0;
 800}
 801
 802/*
 803 * Remove one checksum overlapping a range.
 804 *
 805 * This expects the key to describe the csum pointed to by the path, and it
 806 * expects the csum to overlap the range [bytenr, len]
 807 *
 808 * The csum should not be entirely contained in the range and the range should
 809 * not be entirely contained in the csum.
 810 *
 811 * This calls btrfs_truncate_item with the correct args based on the overlap,
 812 * and fixes up the key as required.
 813 */
 814static noinline void truncate_one_csum(struct btrfs_trans_handle *trans,
 815				       struct btrfs_path *path,
 816				       struct btrfs_key *key,
 817				       u64 bytenr, u64 len)
 818{
 819	struct btrfs_fs_info *fs_info = trans->fs_info;
 820	struct extent_buffer *leaf;
 821	const u32 csum_size = fs_info->csum_size;
 822	u64 csum_end;
 823	u64 end_byte = bytenr + len;
 824	u32 blocksize_bits = fs_info->sectorsize_bits;
 825
 826	leaf = path->nodes[0];
 827	csum_end = btrfs_item_size(leaf, path->slots[0]) / csum_size;
 828	csum_end <<= blocksize_bits;
 829	csum_end += key->offset;
 830
 831	if (key->offset < bytenr && csum_end <= end_byte) {
 832		/*
 833		 *         [ bytenr - len ]
 834		 *         [   ]
 835		 *   [csum     ]
 836		 *   A simple truncate off the end of the item
 837		 */
 838		u32 new_size = (bytenr - key->offset) >> blocksize_bits;
 839		new_size *= csum_size;
 840		btrfs_truncate_item(trans, path, new_size, 1);
 841	} else if (key->offset >= bytenr && csum_end > end_byte &&
 842		   end_byte > key->offset) {
 843		/*
 844		 *         [ bytenr - len ]
 845		 *                 [ ]
 846		 *                 [csum     ]
 847		 * we need to truncate from the beginning of the csum
 848		 */
 849		u32 new_size = (csum_end - end_byte) >> blocksize_bits;
 850		new_size *= csum_size;
 851
 852		btrfs_truncate_item(trans, path, new_size, 0);
 853
 854		key->offset = end_byte;
 855		btrfs_set_item_key_safe(trans, path, key);
 856	} else {
 857		BUG();
 858	}
 859}
 860
 861/*
 862 * Delete the csum items from the csum tree for a given range of bytes.
 863 */
 864int btrfs_del_csums(struct btrfs_trans_handle *trans,
 865		    struct btrfs_root *root, u64 bytenr, u64 len)
 866{
 867	struct btrfs_fs_info *fs_info = trans->fs_info;
 868	struct btrfs_path *path;
 869	struct btrfs_key key;
 870	u64 end_byte = bytenr + len;
 871	u64 csum_end;
 872	struct extent_buffer *leaf;
 873	int ret = 0;
 874	const u32 csum_size = fs_info->csum_size;
 875	u32 blocksize_bits = fs_info->sectorsize_bits;
 876
 877	ASSERT(root->root_key.objectid == BTRFS_CSUM_TREE_OBJECTID ||
 878	       root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
 879
 880	path = btrfs_alloc_path();
 881	if (!path)
 882		return -ENOMEM;
 883
 884	while (1) {
 885		key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 886		key.offset = end_byte - 1;
 887		key.type = BTRFS_EXTENT_CSUM_KEY;
 888
 889		ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 890		if (ret > 0) {
 891			ret = 0;
 892			if (path->slots[0] == 0)
 893				break;
 894			path->slots[0]--;
 895		} else if (ret < 0) {
 896			break;
 897		}
 898
 899		leaf = path->nodes[0];
 900		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 901
 902		if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 903		    key.type != BTRFS_EXTENT_CSUM_KEY) {
 904			break;
 905		}
 906
 907		if (key.offset >= end_byte)
 908			break;
 909
 910		csum_end = btrfs_item_size(leaf, path->slots[0]) / csum_size;
 911		csum_end <<= blocksize_bits;
 912		csum_end += key.offset;
 913
 914		/* this csum ends before we start, we're done */
 915		if (csum_end <= bytenr)
 916			break;
 917
 918		/* delete the entire item, it is inside our range */
 919		if (key.offset >= bytenr && csum_end <= end_byte) {
 920			int del_nr = 1;
 921
 922			/*
 923			 * Check how many csum items preceding this one in this
 924			 * leaf correspond to our range and then delete them all
 925			 * at once.
 926			 */
 927			if (key.offset > bytenr && path->slots[0] > 0) {
 928				int slot = path->slots[0] - 1;
 929
 930				while (slot >= 0) {
 931					struct btrfs_key pk;
 932
 933					btrfs_item_key_to_cpu(leaf, &pk, slot);
 934					if (pk.offset < bytenr ||
 935					    pk.type != BTRFS_EXTENT_CSUM_KEY ||
 936					    pk.objectid !=
 937					    BTRFS_EXTENT_CSUM_OBJECTID)
 938						break;
 939					path->slots[0] = slot;
 940					del_nr++;
 941					key.offset = pk.offset;
 942					slot--;
 943				}
 944			}
 945			ret = btrfs_del_items(trans, root, path,
 946					      path->slots[0], del_nr);
 947			if (ret)
 948				break;
 949			if (key.offset == bytenr)
 950				break;
 951		} else if (key.offset < bytenr && csum_end > end_byte) {
 952			unsigned long offset;
 953			unsigned long shift_len;
 954			unsigned long item_offset;
 955			/*
 956			 *        [ bytenr - len ]
 957			 *     [csum                ]
 958			 *
 959			 * Our bytes are in the middle of the csum,
 960			 * we need to split this item and insert a new one.
 961			 *
 962			 * But we can't drop the path because the
 963			 * csum could change, get removed, extended etc.
 964			 *
 965			 * The trick here is the max size of a csum item leaves
 966			 * enough room in the tree block for a single
 967			 * item header.  So, we split the item in place,
 968			 * adding a new header pointing to the existing
 969			 * bytes.  Then we loop around again and we have
 970			 * a nicely formed csum item that we can neatly
 971			 * truncate.
 972			 */
 973			offset = (bytenr - key.offset) >> blocksize_bits;
 974			offset *= csum_size;
 975
 976			shift_len = (len >> blocksize_bits) * csum_size;
 977
 978			item_offset = btrfs_item_ptr_offset(leaf,
 979							    path->slots[0]);
 980
 981			memzero_extent_buffer(leaf, item_offset + offset,
 982					     shift_len);
 983			key.offset = bytenr;
 984
 985			/*
 986			 * btrfs_split_item returns -EAGAIN when the
 987			 * item changed size or key
 988			 */
 989			ret = btrfs_split_item(trans, root, path, &key, offset);
 990			if (ret && ret != -EAGAIN) {
 991				btrfs_abort_transaction(trans, ret);
 992				break;
 993			}
 994			ret = 0;
 995
 996			key.offset = end_byte - 1;
 997		} else {
 998			truncate_one_csum(trans, path, &key, bytenr, len);
 999			if (key.offset < bytenr)
1000				break;
1001		}
1002		btrfs_release_path(path);
1003	}
1004	btrfs_free_path(path);
1005	return ret;
1006}
1007
1008static int find_next_csum_offset(struct btrfs_root *root,
1009				 struct btrfs_path *path,
1010				 u64 *next_offset)
1011{
1012	const u32 nritems = btrfs_header_nritems(path->nodes[0]);
1013	struct btrfs_key found_key;
1014	int slot = path->slots[0] + 1;
1015	int ret;
1016
1017	if (nritems == 0 || slot >= nritems) {
1018		ret = btrfs_next_leaf(root, path);
1019		if (ret < 0) {
1020			return ret;
1021		} else if (ret > 0) {
1022			*next_offset = (u64)-1;
1023			return 0;
1024		}
1025		slot = path->slots[0];
1026	}
1027
1028	btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
1029
1030	if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
1031	    found_key.type != BTRFS_EXTENT_CSUM_KEY)
1032		*next_offset = (u64)-1;
1033	else
1034		*next_offset = found_key.offset;
1035
1036	return 0;
1037}
1038
1039int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
1040			   struct btrfs_root *root,
1041			   struct btrfs_ordered_sum *sums)
1042{
1043	struct btrfs_fs_info *fs_info = root->fs_info;
1044	struct btrfs_key file_key;
1045	struct btrfs_key found_key;
1046	struct btrfs_path *path;
1047	struct btrfs_csum_item *item;
1048	struct btrfs_csum_item *item_end;
1049	struct extent_buffer *leaf = NULL;
1050	u64 next_offset;
1051	u64 total_bytes = 0;
1052	u64 csum_offset;
1053	u64 bytenr;
1054	u32 ins_size;
1055	int index = 0;
1056	int found_next;
1057	int ret;
1058	const u32 csum_size = fs_info->csum_size;
1059
1060	path = btrfs_alloc_path();
1061	if (!path)
1062		return -ENOMEM;
1063again:
1064	next_offset = (u64)-1;
1065	found_next = 0;
1066	bytenr = sums->logical + total_bytes;
1067	file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
1068	file_key.offset = bytenr;
1069	file_key.type = BTRFS_EXTENT_CSUM_KEY;
1070
1071	item = btrfs_lookup_csum(trans, root, path, bytenr, 1);
1072	if (!IS_ERR(item)) {
1073		ret = 0;
1074		leaf = path->nodes[0];
1075		item_end = btrfs_item_ptr(leaf, path->slots[0],
1076					  struct btrfs_csum_item);
1077		item_end = (struct btrfs_csum_item *)((char *)item_end +
1078			   btrfs_item_size(leaf, path->slots[0]));
1079		goto found;
1080	}
1081	ret = PTR_ERR(item);
1082	if (ret != -EFBIG && ret != -ENOENT)
1083		goto out;
1084
1085	if (ret == -EFBIG) {
1086		u32 item_size;
1087		/* we found one, but it isn't big enough yet */
1088		leaf = path->nodes[0];
1089		item_size = btrfs_item_size(leaf, path->slots[0]);
1090		if ((item_size / csum_size) >=
1091		    MAX_CSUM_ITEMS(fs_info, csum_size)) {
1092			/* already at max size, make a new one */
1093			goto insert;
1094		}
1095	} else {
1096		/* We didn't find a csum item, insert one. */
1097		ret = find_next_csum_offset(root, path, &next_offset);
1098		if (ret < 0)
1099			goto out;
1100		found_next = 1;
1101		goto insert;
1102	}
1103
1104	/*
1105	 * At this point, we know the tree has a checksum item that ends at an
1106	 * offset matching the start of the checksum range we want to insert.
1107	 * We try to extend that item as much as possible and then add as many
1108	 * checksums to it as they fit.
1109	 *
1110	 * First check if the leaf has enough free space for at least one
1111	 * checksum. If it has go directly to the item extension code, otherwise
1112	 * release the path and do a search for insertion before the extension.
1113	 */
1114	if (btrfs_leaf_free_space(leaf) >= csum_size) {
1115		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1116		csum_offset = (bytenr - found_key.offset) >>
1117			fs_info->sectorsize_bits;
1118		goto extend_csum;
1119	}
1120
1121	btrfs_release_path(path);
1122	path->search_for_extension = 1;
1123	ret = btrfs_search_slot(trans, root, &file_key, path,
1124				csum_size, 1);
1125	path->search_for_extension = 0;
1126	if (ret < 0)
1127		goto out;
1128
1129	if (ret > 0) {
1130		if (path->slots[0] == 0)
1131			goto insert;
1132		path->slots[0]--;
1133	}
1134
1135	leaf = path->nodes[0];
1136	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1137	csum_offset = (bytenr - found_key.offset) >> fs_info->sectorsize_bits;
1138
1139	if (found_key.type != BTRFS_EXTENT_CSUM_KEY ||
1140	    found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
1141	    csum_offset >= MAX_CSUM_ITEMS(fs_info, csum_size)) {
1142		goto insert;
1143	}
1144
1145extend_csum:
1146	if (csum_offset == btrfs_item_size(leaf, path->slots[0]) /
1147	    csum_size) {
1148		int extend_nr;
1149		u64 tmp;
1150		u32 diff;
1151
1152		tmp = sums->len - total_bytes;
1153		tmp >>= fs_info->sectorsize_bits;
1154		WARN_ON(tmp < 1);
1155		extend_nr = max_t(int, 1, tmp);
1156
1157		/*
1158		 * A log tree can already have checksum items with a subset of
1159		 * the checksums we are trying to log. This can happen after
1160		 * doing a sequence of partial writes into prealloc extents and
1161		 * fsyncs in between, with a full fsync logging a larger subrange
1162		 * of an extent for which a previous fast fsync logged a smaller
1163		 * subrange. And this happens in particular due to merging file
1164		 * extent items when we complete an ordered extent for a range
1165		 * covered by a prealloc extent - this is done at
1166		 * btrfs_mark_extent_written().
1167		 *
1168		 * So if we try to extend the previous checksum item, which has
1169		 * a range that ends at the start of the range we want to insert,
1170		 * make sure we don't extend beyond the start offset of the next
1171		 * checksum item. If we are at the last item in the leaf, then
1172		 * forget the optimization of extending and add a new checksum
1173		 * item - it is not worth the complexity of releasing the path,
1174		 * getting the first key for the next leaf, repeat the btree
1175		 * search, etc, because log trees are temporary anyway and it
1176		 * would only save a few bytes of leaf space.
1177		 */
1178		if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
1179			if (path->slots[0] + 1 >=
1180			    btrfs_header_nritems(path->nodes[0])) {
1181				ret = find_next_csum_offset(root, path, &next_offset);
1182				if (ret < 0)
1183					goto out;
1184				found_next = 1;
1185				goto insert;
1186			}
1187
1188			ret = find_next_csum_offset(root, path, &next_offset);
1189			if (ret < 0)
1190				goto out;
1191
1192			tmp = (next_offset - bytenr) >> fs_info->sectorsize_bits;
1193			if (tmp <= INT_MAX)
1194				extend_nr = min_t(int, extend_nr, tmp);
1195		}
1196
1197		diff = (csum_offset + extend_nr) * csum_size;
1198		diff = min(diff,
1199			   MAX_CSUM_ITEMS(fs_info, csum_size) * csum_size);
1200
1201		diff = diff - btrfs_item_size(leaf, path->slots[0]);
1202		diff = min_t(u32, btrfs_leaf_free_space(leaf), diff);
1203		diff /= csum_size;
1204		diff *= csum_size;
1205
1206		btrfs_extend_item(trans, path, diff);
1207		ret = 0;
1208		goto csum;
1209	}
1210
1211insert:
1212	btrfs_release_path(path);
1213	csum_offset = 0;
1214	if (found_next) {
1215		u64 tmp;
1216
1217		tmp = sums->len - total_bytes;
1218		tmp >>= fs_info->sectorsize_bits;
1219		tmp = min(tmp, (next_offset - file_key.offset) >>
1220					 fs_info->sectorsize_bits);
1221
1222		tmp = max_t(u64, 1, tmp);
1223		tmp = min_t(u64, tmp, MAX_CSUM_ITEMS(fs_info, csum_size));
1224		ins_size = csum_size * tmp;
1225	} else {
1226		ins_size = csum_size;
1227	}
1228	ret = btrfs_insert_empty_item(trans, root, path, &file_key,
1229				      ins_size);
1230	if (ret < 0)
1231		goto out;
1232	if (WARN_ON(ret != 0))
1233		goto out;
1234	leaf = path->nodes[0];
1235csum:
1236	item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
1237	item_end = (struct btrfs_csum_item *)((unsigned char *)item +
1238				      btrfs_item_size(leaf, path->slots[0]));
1239	item = (struct btrfs_csum_item *)((unsigned char *)item +
1240					  csum_offset * csum_size);
1241found:
1242	ins_size = (u32)(sums->len - total_bytes) >> fs_info->sectorsize_bits;
1243	ins_size *= csum_size;
1244	ins_size = min_t(u32, (unsigned long)item_end - (unsigned long)item,
1245			      ins_size);
1246	write_extent_buffer(leaf, sums->sums + index, (unsigned long)item,
1247			    ins_size);
1248
1249	index += ins_size;
1250	ins_size /= csum_size;
1251	total_bytes += ins_size * fs_info->sectorsize;
1252
1253	btrfs_mark_buffer_dirty(trans, path->nodes[0]);
1254	if (total_bytes < sums->len) {
1255		btrfs_release_path(path);
1256		cond_resched();
1257		goto again;
1258	}
1259out:
1260	btrfs_free_path(path);
1261	return ret;
1262}
1263
1264void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
1265				     const struct btrfs_path *path,
1266				     struct btrfs_file_extent_item *fi,
1267				     struct extent_map *em)
1268{
1269	struct btrfs_fs_info *fs_info = inode->root->fs_info;
1270	struct btrfs_root *root = inode->root;
1271	struct extent_buffer *leaf = path->nodes[0];
1272	const int slot = path->slots[0];
1273	struct btrfs_key key;
1274	u64 extent_start, extent_end;
1275	u64 bytenr;
1276	u8 type = btrfs_file_extent_type(leaf, fi);
1277	int compress_type = btrfs_file_extent_compression(leaf, fi);
1278
1279	btrfs_item_key_to_cpu(leaf, &key, slot);
1280	extent_start = key.offset;
1281	extent_end = btrfs_file_extent_end(path);
1282	em->ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1283	em->generation = btrfs_file_extent_generation(leaf, fi);
1284	if (type == BTRFS_FILE_EXTENT_REG ||
1285	    type == BTRFS_FILE_EXTENT_PREALLOC) {
1286		em->start = extent_start;
1287		em->len = extent_end - extent_start;
1288		em->orig_start = extent_start -
1289			btrfs_file_extent_offset(leaf, fi);
1290		em->orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
1291		bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1292		if (bytenr == 0) {
1293			em->block_start = EXTENT_MAP_HOLE;
1294			return;
1295		}
1296		if (compress_type != BTRFS_COMPRESS_NONE) {
1297			extent_map_set_compression(em, compress_type);
1298			em->block_start = bytenr;
1299			em->block_len = em->orig_block_len;
1300		} else {
1301			bytenr += btrfs_file_extent_offset(leaf, fi);
1302			em->block_start = bytenr;
1303			em->block_len = em->len;
1304			if (type == BTRFS_FILE_EXTENT_PREALLOC)
1305				em->flags |= EXTENT_FLAG_PREALLOC;
1306		}
1307	} else if (type == BTRFS_FILE_EXTENT_INLINE) {
1308		em->block_start = EXTENT_MAP_INLINE;
1309		em->start = extent_start;
1310		em->len = extent_end - extent_start;
1311		/*
1312		 * Initialize orig_start and block_len with the same values
1313		 * as in inode.c:btrfs_get_extent().
1314		 */
1315		em->orig_start = EXTENT_MAP_HOLE;
1316		em->block_len = (u64)-1;
1317		extent_map_set_compression(em, compress_type);
1318	} else {
1319		btrfs_err(fs_info,
1320			  "unknown file extent item type %d, inode %llu, offset %llu, "
1321			  "root %llu", type, btrfs_ino(inode), extent_start,
1322			  root->root_key.objectid);
1323	}
1324}
1325
1326/*
1327 * Returns the end offset (non inclusive) of the file extent item the given path
1328 * points to. If it points to an inline extent, the returned offset is rounded
1329 * up to the sector size.
1330 */
1331u64 btrfs_file_extent_end(const struct btrfs_path *path)
1332{
1333	const struct extent_buffer *leaf = path->nodes[0];
1334	const int slot = path->slots[0];
1335	struct btrfs_file_extent_item *fi;
1336	struct btrfs_key key;
1337	u64 end;
1338
1339	btrfs_item_key_to_cpu(leaf, &key, slot);
1340	ASSERT(key.type == BTRFS_EXTENT_DATA_KEY);
1341	fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
1342
1343	if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE) {
1344		end = btrfs_file_extent_ram_bytes(leaf, fi);
1345		end = ALIGN(key.offset + end, leaf->fs_info->sectorsize);
1346	} else {
1347		end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
1348	}
1349
1350	return end;
1351}