916 lines · c
1// SPDX-License-Identifier: GPL-2.02 3#include <linux/blkdev.h>4#include <linux/iversion.h>5#include "ctree.h"6#include "fs.h"7#include "messages.h"8#include "compression.h"9#include "delalloc-space.h"10#include "disk-io.h"11#include "reflink.h"12#include "transaction.h"13#include "subpage.h"14#include "accessors.h"15#include "file-item.h"16#include "file.h"17#include "super.h"18 19#define BTRFS_MAX_DEDUPE_LEN SZ_16M20 21static int clone_finish_inode_update(struct btrfs_trans_handle *trans,22 struct inode *inode,23 u64 endoff,24 const u64 destoff,25 const u64 olen,26 int no_time_update)27{28 int ret;29 30 inode_inc_iversion(inode);31 if (!no_time_update) {32 inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));33 }34 /*35 * We round up to the block size at eof when determining which36 * extents to clone above, but shouldn't round up the file size.37 */38 if (endoff > destoff + olen)39 endoff = destoff + olen;40 if (endoff > inode->i_size) {41 i_size_write(inode, endoff);42 btrfs_inode_safe_disk_i_size_write(BTRFS_I(inode), 0);43 }44 45 ret = btrfs_update_inode(trans, BTRFS_I(inode));46 if (ret) {47 btrfs_abort_transaction(trans, ret);48 btrfs_end_transaction(trans);49 goto out;50 }51 ret = btrfs_end_transaction(trans);52out:53 return ret;54}55 56static int copy_inline_to_page(struct btrfs_inode *inode,57 const u64 file_offset,58 char *inline_data,59 const u64 size,60 const u64 datal,61 const u8 comp_type)62{63 struct btrfs_fs_info *fs_info = inode->root->fs_info;64 const u32 block_size = fs_info->sectorsize;65 const u64 range_end = file_offset + block_size - 1;66 const size_t inline_size = size - btrfs_file_extent_calc_inline_size(0);67 char *data_start = inline_data + btrfs_file_extent_calc_inline_size(0);68 struct extent_changeset *data_reserved = NULL;69 struct folio *folio = NULL;70 struct address_space *mapping = inode->vfs_inode.i_mapping;71 int ret;72 73 ASSERT(IS_ALIGNED(file_offset, block_size));74 75 /*76 * We have flushed and locked the ranges of the source and destination77 * inodes, we also have locked the inodes, so we are safe to do a78 * reservation here. Also we must not do the reservation while holding79 * a transaction open, otherwise we would deadlock.80 */81 ret = btrfs_delalloc_reserve_space(inode, &data_reserved, file_offset,82 block_size);83 if (ret)84 goto out;85 86 folio = __filemap_get_folio(mapping, file_offset >> PAGE_SHIFT,87 FGP_LOCK | FGP_ACCESSED | FGP_CREAT,88 btrfs_alloc_write_mask(mapping));89 if (IS_ERR(folio)) {90 ret = -ENOMEM;91 goto out_unlock;92 }93 94 ret = set_folio_extent_mapped(folio);95 if (ret < 0)96 goto out_unlock;97 98 clear_extent_bit(&inode->io_tree, file_offset, range_end,99 EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,100 NULL);101 ret = btrfs_set_extent_delalloc(inode, file_offset, range_end, 0, NULL);102 if (ret)103 goto out_unlock;104 105 /*106 * After dirtying the page our caller will need to start a transaction,107 * and if we are low on metadata free space, that can cause flushing of108 * delalloc for all inodes in order to get metadata space released.109 * However we are holding the range locked for the whole duration of110 * the clone/dedupe operation, so we may deadlock if that happens and no111 * other task releases enough space. So mark this inode as not being112 * possible to flush to avoid such deadlock. We will clear that flag113 * when we finish cloning all extents, since a transaction is started114 * after finding each extent to clone.115 */116 set_bit(BTRFS_INODE_NO_DELALLOC_FLUSH, &inode->runtime_flags);117 118 if (comp_type == BTRFS_COMPRESS_NONE) {119 memcpy_to_folio(folio, offset_in_folio(folio, file_offset), data_start,120 datal);121 } else {122 ret = btrfs_decompress(comp_type, data_start, folio,123 offset_in_folio(folio, file_offset),124 inline_size, datal);125 if (ret)126 goto out_unlock;127 flush_dcache_folio(folio);128 }129 130 /*131 * If our inline data is smaller then the block/page size, then the132 * remaining of the block/page is equivalent to zeroes. We had something133 * like the following done:134 *135 * $ xfs_io -f -c "pwrite -S 0xab 0 500" file136 * $ sync # (or fsync)137 * $ xfs_io -c "falloc 0 4K" file138 * $ xfs_io -c "pwrite -S 0xcd 4K 4K"139 *140 * So what's in the range [500, 4095] corresponds to zeroes.141 */142 if (datal < block_size)143 folio_zero_range(folio, datal, block_size - datal);144 145 btrfs_folio_set_uptodate(fs_info, folio, file_offset, block_size);146 btrfs_folio_clear_checked(fs_info, folio, file_offset, block_size);147 btrfs_folio_set_dirty(fs_info, folio, file_offset, block_size);148out_unlock:149 if (!IS_ERR(folio)) {150 folio_unlock(folio);151 folio_put(folio);152 }153 if (ret)154 btrfs_delalloc_release_space(inode, data_reserved, file_offset,155 block_size, true);156 btrfs_delalloc_release_extents(inode, block_size);157out:158 extent_changeset_free(data_reserved);159 160 return ret;161}162 163/*164 * Deal with cloning of inline extents. We try to copy the inline extent from165 * the source inode to destination inode when possible. When not possible we166 * copy the inline extent's data into the respective page of the inode.167 */168static int clone_copy_inline_extent(struct inode *dst,169 struct btrfs_path *path,170 struct btrfs_key *new_key,171 const u64 drop_start,172 const u64 datal,173 const u64 size,174 const u8 comp_type,175 char *inline_data,176 struct btrfs_trans_handle **trans_out)177{178 struct btrfs_fs_info *fs_info = inode_to_fs_info(dst);179 struct btrfs_root *root = BTRFS_I(dst)->root;180 const u64 aligned_end = ALIGN(new_key->offset + datal,181 fs_info->sectorsize);182 struct btrfs_trans_handle *trans = NULL;183 struct btrfs_drop_extents_args drop_args = { 0 };184 int ret;185 struct btrfs_key key;186 187 if (new_key->offset > 0) {188 ret = copy_inline_to_page(BTRFS_I(dst), new_key->offset,189 inline_data, size, datal, comp_type);190 goto out;191 }192 193 key.objectid = btrfs_ino(BTRFS_I(dst));194 key.type = BTRFS_EXTENT_DATA_KEY;195 key.offset = 0;196 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);197 if (ret < 0) {198 return ret;199 } else if (ret > 0) {200 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {201 ret = btrfs_next_leaf(root, path);202 if (ret < 0)203 return ret;204 else if (ret > 0)205 goto copy_inline_extent;206 }207 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);208 if (key.objectid == btrfs_ino(BTRFS_I(dst)) &&209 key.type == BTRFS_EXTENT_DATA_KEY) {210 /*211 * There's an implicit hole at file offset 0, copy the212 * inline extent's data to the page.213 */214 ASSERT(key.offset > 0);215 goto copy_to_page;216 }217 } else if (i_size_read(dst) <= datal) {218 struct btrfs_file_extent_item *ei;219 220 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],221 struct btrfs_file_extent_item);222 /*223 * If it's an inline extent replace it with the source inline224 * extent, otherwise copy the source inline extent data into225 * the respective page at the destination inode.226 */227 if (btrfs_file_extent_type(path->nodes[0], ei) ==228 BTRFS_FILE_EXTENT_INLINE)229 goto copy_inline_extent;230 231 goto copy_to_page;232 }233 234copy_inline_extent:235 /*236 * We have no extent items, or we have an extent at offset 0 which may237 * or may not be inlined. All these cases are dealt the same way.238 */239 if (i_size_read(dst) > datal) {240 /*241 * At the destination offset 0 we have either a hole, a regular242 * extent or an inline extent larger then the one we want to243 * clone. Deal with all these cases by copying the inline extent244 * data into the respective page at the destination inode.245 */246 goto copy_to_page;247 }248 249 /*250 * Release path before starting a new transaction so we don't hold locks251 * that would confuse lockdep.252 */253 btrfs_release_path(path);254 /*255 * If we end up here it means were copy the inline extent into a leaf256 * of the destination inode. We know we will drop or adjust at most one257 * extent item in the destination root.258 *259 * 1 unit - adjusting old extent (we may have to split it)260 * 1 unit - add new extent261 * 1 unit - inode update262 */263 trans = btrfs_start_transaction(root, 3);264 if (IS_ERR(trans)) {265 ret = PTR_ERR(trans);266 trans = NULL;267 goto out;268 }269 drop_args.path = path;270 drop_args.start = drop_start;271 drop_args.end = aligned_end;272 drop_args.drop_cache = true;273 ret = btrfs_drop_extents(trans, root, BTRFS_I(dst), &drop_args);274 if (ret)275 goto out;276 ret = btrfs_insert_empty_item(trans, root, path, new_key, size);277 if (ret)278 goto out;279 280 write_extent_buffer(path->nodes[0], inline_data,281 btrfs_item_ptr_offset(path->nodes[0],282 path->slots[0]),283 size);284 btrfs_update_inode_bytes(BTRFS_I(dst), datal, drop_args.bytes_found);285 btrfs_set_inode_full_sync(BTRFS_I(dst));286 ret = btrfs_inode_set_file_extent_range(BTRFS_I(dst), 0, aligned_end);287out:288 if (!ret && !trans) {289 /*290 * No transaction here means we copied the inline extent into a291 * page of the destination inode.292 *293 * 1 unit to update inode item294 */295 trans = btrfs_start_transaction(root, 1);296 if (IS_ERR(trans)) {297 ret = PTR_ERR(trans);298 trans = NULL;299 }300 }301 if (ret && trans) {302 btrfs_abort_transaction(trans, ret);303 btrfs_end_transaction(trans);304 }305 if (!ret)306 *trans_out = trans;307 308 return ret;309 310copy_to_page:311 /*312 * Release our path because we don't need it anymore and also because313 * copy_inline_to_page() needs to reserve data and metadata, which may314 * need to flush delalloc when we are low on available space and315 * therefore cause a deadlock if writeback of an inline extent needs to316 * write to the same leaf or an ordered extent completion needs to write317 * to the same leaf.318 */319 btrfs_release_path(path);320 321 ret = copy_inline_to_page(BTRFS_I(dst), new_key->offset,322 inline_data, size, datal, comp_type);323 goto out;324}325 326/*327 * Clone a range from inode file to another.328 *329 * @src: Inode to clone from330 * @inode: Inode to clone to331 * @off: Offset within source to start clone from332 * @olen: Original length, passed by user, of range to clone333 * @olen_aligned: Block-aligned value of olen334 * @destoff: Offset within @inode to start clone335 * @no_time_update: Whether to update mtime/ctime on the target inode336 */337static int btrfs_clone(struct inode *src, struct inode *inode,338 const u64 off, const u64 olen, const u64 olen_aligned,339 const u64 destoff, int no_time_update)340{341 struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);342 struct btrfs_path *path = NULL;343 struct extent_buffer *leaf;344 struct btrfs_trans_handle *trans;345 char *buf = NULL;346 struct btrfs_key key;347 u32 nritems;348 int slot;349 int ret;350 const u64 len = olen_aligned;351 u64 last_dest_end = destoff;352 u64 prev_extent_end = off;353 354 ret = -ENOMEM;355 buf = kvmalloc(fs_info->nodesize, GFP_KERNEL);356 if (!buf)357 return ret;358 359 path = btrfs_alloc_path();360 if (!path) {361 kvfree(buf);362 return ret;363 }364 365 path->reada = READA_FORWARD;366 /* Clone data */367 key.objectid = btrfs_ino(BTRFS_I(src));368 key.type = BTRFS_EXTENT_DATA_KEY;369 key.offset = off;370 371 while (1) {372 struct btrfs_file_extent_item *extent;373 u64 extent_gen;374 int type;375 u32 size;376 struct btrfs_key new_key;377 u64 disko = 0, diskl = 0;378 u64 datao = 0, datal = 0;379 u8 comp;380 u64 drop_start;381 382 /* Note the key will change type as we walk through the tree */383 ret = btrfs_search_slot(NULL, BTRFS_I(src)->root, &key, path,384 0, 0);385 if (ret < 0)386 goto out;387 /*388 * First search, if no extent item that starts at offset off was389 * found but the previous item is an extent item, it's possible390 * it might overlap our target range, therefore process it.391 */392 if (key.offset == off && ret > 0 && path->slots[0] > 0) {393 btrfs_item_key_to_cpu(path->nodes[0], &key,394 path->slots[0] - 1);395 if (key.type == BTRFS_EXTENT_DATA_KEY)396 path->slots[0]--;397 }398 399 nritems = btrfs_header_nritems(path->nodes[0]);400process_slot:401 if (path->slots[0] >= nritems) {402 ret = btrfs_next_leaf(BTRFS_I(src)->root, path);403 if (ret < 0)404 goto out;405 if (ret > 0)406 break;407 nritems = btrfs_header_nritems(path->nodes[0]);408 }409 leaf = path->nodes[0];410 slot = path->slots[0];411 412 btrfs_item_key_to_cpu(leaf, &key, slot);413 if (key.type > BTRFS_EXTENT_DATA_KEY ||414 key.objectid != btrfs_ino(BTRFS_I(src)))415 break;416 417 ASSERT(key.type == BTRFS_EXTENT_DATA_KEY);418 419 extent = btrfs_item_ptr(leaf, slot,420 struct btrfs_file_extent_item);421 extent_gen = btrfs_file_extent_generation(leaf, extent);422 comp = btrfs_file_extent_compression(leaf, extent);423 type = btrfs_file_extent_type(leaf, extent);424 if (type == BTRFS_FILE_EXTENT_REG ||425 type == BTRFS_FILE_EXTENT_PREALLOC) {426 disko = btrfs_file_extent_disk_bytenr(leaf, extent);427 diskl = btrfs_file_extent_disk_num_bytes(leaf, extent);428 datao = btrfs_file_extent_offset(leaf, extent);429 datal = btrfs_file_extent_num_bytes(leaf, extent);430 } else if (type == BTRFS_FILE_EXTENT_INLINE) {431 /* Take upper bound, may be compressed */432 datal = btrfs_file_extent_ram_bytes(leaf, extent);433 }434 435 /*436 * The first search might have left us at an extent item that437 * ends before our target range's start, can happen if we have438 * holes and NO_HOLES feature enabled.439 *440 * Subsequent searches may leave us on a file range we have441 * processed before - this happens due to a race with ordered442 * extent completion for a file range that is outside our source443 * range, but that range was part of a file extent item that444 * also covered a leading part of our source range.445 */446 if (key.offset + datal <= prev_extent_end) {447 path->slots[0]++;448 goto process_slot;449 } else if (key.offset >= off + len) {450 break;451 }452 453 prev_extent_end = key.offset + datal;454 size = btrfs_item_size(leaf, slot);455 read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf, slot),456 size);457 458 btrfs_release_path(path);459 460 memcpy(&new_key, &key, sizeof(new_key));461 new_key.objectid = btrfs_ino(BTRFS_I(inode));462 if (off <= key.offset)463 new_key.offset = key.offset + destoff - off;464 else465 new_key.offset = destoff;466 467 /*468 * Deal with a hole that doesn't have an extent item that469 * represents it (NO_HOLES feature enabled).470 * This hole is either in the middle of the cloning range or at471 * the beginning (fully overlaps it or partially overlaps it).472 */473 if (new_key.offset != last_dest_end)474 drop_start = last_dest_end;475 else476 drop_start = new_key.offset;477 478 if (type == BTRFS_FILE_EXTENT_REG ||479 type == BTRFS_FILE_EXTENT_PREALLOC) {480 struct btrfs_replace_extent_info clone_info;481 482 /*483 * a | --- range to clone ---| b484 * | ------------- extent ------------- |485 */486 487 /* Subtract range b */488 if (key.offset + datal > off + len)489 datal = off + len - key.offset;490 491 /* Subtract range a */492 if (off > key.offset) {493 datao += off - key.offset;494 datal -= off - key.offset;495 }496 497 clone_info.disk_offset = disko;498 clone_info.disk_len = diskl;499 clone_info.data_offset = datao;500 clone_info.data_len = datal;501 clone_info.file_offset = new_key.offset;502 clone_info.extent_buf = buf;503 clone_info.is_new_extent = false;504 clone_info.update_times = !no_time_update;505 ret = btrfs_replace_file_extents(BTRFS_I(inode), path,506 drop_start, new_key.offset + datal - 1,507 &clone_info, &trans);508 if (ret)509 goto out;510 } else {511 ASSERT(type == BTRFS_FILE_EXTENT_INLINE);512 /*513 * Inline extents always have to start at file offset 0514 * and can never be bigger then the sector size. We can515 * never clone only parts of an inline extent, since all516 * reflink operations must start at a sector size aligned517 * offset, and the length must be aligned too or end at518 * the i_size (which implies the whole inlined data).519 */520 ASSERT(key.offset == 0);521 ASSERT(datal <= fs_info->sectorsize);522 if (WARN_ON(type != BTRFS_FILE_EXTENT_INLINE) ||523 WARN_ON(key.offset != 0) ||524 WARN_ON(datal > fs_info->sectorsize)) {525 ret = -EUCLEAN;526 goto out;527 }528 529 ret = clone_copy_inline_extent(inode, path, &new_key,530 drop_start, datal, size,531 comp, buf, &trans);532 if (ret)533 goto out;534 }535 536 btrfs_release_path(path);537 538 /*539 * Whenever we share an extent we update the last_reflink_trans540 * of each inode to the current transaction. This is needed to541 * make sure fsync does not log multiple checksum items with542 * overlapping ranges (because some extent items might refer543 * only to sections of the original extent). For the destination544 * inode we do this regardless of the generation of the extents545 * or even if they are inline extents or explicit holes, to make546 * sure a full fsync does not skip them. For the source inode,547 * we only need to update last_reflink_trans in case it's a new548 * extent that is not a hole or an inline extent, to deal with549 * the checksums problem on fsync.550 */551 if (extent_gen == trans->transid && disko > 0)552 BTRFS_I(src)->last_reflink_trans = trans->transid;553 554 BTRFS_I(inode)->last_reflink_trans = trans->transid;555 556 last_dest_end = ALIGN(new_key.offset + datal,557 fs_info->sectorsize);558 ret = clone_finish_inode_update(trans, inode, last_dest_end,559 destoff, olen, no_time_update);560 if (ret)561 goto out;562 if (new_key.offset + datal >= destoff + len)563 break;564 565 btrfs_release_path(path);566 key.offset = prev_extent_end;567 568 if (fatal_signal_pending(current)) {569 ret = -EINTR;570 goto out;571 }572 573 cond_resched();574 }575 ret = 0;576 577 if (last_dest_end < destoff + len) {578 /*579 * We have an implicit hole that fully or partially overlaps our580 * cloning range at its end. This means that we either have the581 * NO_HOLES feature enabled or the implicit hole happened due to582 * mixing buffered and direct IO writes against this file.583 */584 btrfs_release_path(path);585 586 /*587 * When using NO_HOLES and we are cloning a range that covers588 * only a hole (no extents) into a range beyond the current589 * i_size, punching a hole in the target range will not create590 * an extent map defining a hole, because the range starts at or591 * beyond current i_size. If the file previously had an i_size592 * greater than the new i_size set by this clone operation, we593 * need to make sure the next fsync is a full fsync, so that it594 * detects and logs a hole covering a range from the current595 * i_size to the new i_size. If the clone range covers extents,596 * besides a hole, then we know the full sync flag was already597 * set by previous calls to btrfs_replace_file_extents() that598 * replaced file extent items.599 */600 if (last_dest_end >= i_size_read(inode))601 btrfs_set_inode_full_sync(BTRFS_I(inode));602 603 ret = btrfs_replace_file_extents(BTRFS_I(inode), path,604 last_dest_end, destoff + len - 1, NULL, &trans);605 if (ret)606 goto out;607 608 ret = clone_finish_inode_update(trans, inode, destoff + len,609 destoff, olen, no_time_update);610 }611 612out:613 btrfs_free_path(path);614 kvfree(buf);615 clear_bit(BTRFS_INODE_NO_DELALLOC_FLUSH, &BTRFS_I(inode)->runtime_flags);616 617 return ret;618}619 620static void btrfs_double_mmap_lock(struct inode *inode1, struct inode *inode2)621{622 if (inode1 < inode2)623 swap(inode1, inode2);624 down_write(&BTRFS_I(inode1)->i_mmap_lock);625 down_write_nested(&BTRFS_I(inode2)->i_mmap_lock, SINGLE_DEPTH_NESTING);626}627 628static void btrfs_double_mmap_unlock(struct inode *inode1, struct inode *inode2)629{630 up_write(&BTRFS_I(inode1)->i_mmap_lock);631 up_write(&BTRFS_I(inode2)->i_mmap_lock);632}633 634static int btrfs_extent_same_range(struct inode *src, u64 loff, u64 len,635 struct inode *dst, u64 dst_loff)636{637 const u64 end = dst_loff + len - 1;638 struct extent_state *cached_state = NULL;639 struct btrfs_fs_info *fs_info = BTRFS_I(src)->root->fs_info;640 const u64 bs = fs_info->sectorsize;641 int ret;642 643 /*644 * Lock destination range to serialize with concurrent readahead(), and645 * we are safe from concurrency with relocation of source extents646 * because we have already locked the inode's i_mmap_lock in exclusive647 * mode.648 */649 lock_extent(&BTRFS_I(dst)->io_tree, dst_loff, end, &cached_state);650 ret = btrfs_clone(src, dst, loff, len, ALIGN(len, bs), dst_loff, 1);651 unlock_extent(&BTRFS_I(dst)->io_tree, dst_loff, end, &cached_state);652 653 btrfs_btree_balance_dirty(fs_info);654 655 return ret;656}657 658static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,659 struct inode *dst, u64 dst_loff)660{661 int ret = 0;662 u64 i, tail_len, chunk_count;663 struct btrfs_root *root_dst = BTRFS_I(dst)->root;664 665 spin_lock(&root_dst->root_item_lock);666 if (root_dst->send_in_progress) {667 btrfs_warn_rl(root_dst->fs_info,668"cannot deduplicate to root %llu while send operations are using it (%d in progress)",669 btrfs_root_id(root_dst),670 root_dst->send_in_progress);671 spin_unlock(&root_dst->root_item_lock);672 return -EAGAIN;673 }674 root_dst->dedupe_in_progress++;675 spin_unlock(&root_dst->root_item_lock);676 677 tail_len = olen % BTRFS_MAX_DEDUPE_LEN;678 chunk_count = div_u64(olen, BTRFS_MAX_DEDUPE_LEN);679 680 for (i = 0; i < chunk_count; i++) {681 ret = btrfs_extent_same_range(src, loff, BTRFS_MAX_DEDUPE_LEN,682 dst, dst_loff);683 if (ret)684 goto out;685 686 loff += BTRFS_MAX_DEDUPE_LEN;687 dst_loff += BTRFS_MAX_DEDUPE_LEN;688 }689 690 if (tail_len > 0)691 ret = btrfs_extent_same_range(src, loff, tail_len, dst, dst_loff);692out:693 spin_lock(&root_dst->root_item_lock);694 root_dst->dedupe_in_progress--;695 spin_unlock(&root_dst->root_item_lock);696 697 return ret;698}699 700static noinline int btrfs_clone_files(struct file *file, struct file *file_src,701 u64 off, u64 olen, u64 destoff)702{703 struct extent_state *cached_state = NULL;704 struct inode *inode = file_inode(file);705 struct inode *src = file_inode(file_src);706 struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);707 int ret;708 int wb_ret;709 u64 len = olen;710 u64 bs = fs_info->sectorsize;711 u64 end;712 713 /*714 * VFS's generic_remap_file_range_prep() protects us from cloning the715 * eof block into the middle of a file, which would result in corruption716 * if the file size is not blocksize aligned. So we don't need to check717 * for that case here.718 */719 if (off + len == src->i_size)720 len = ALIGN(src->i_size, bs) - off;721 722 if (destoff > inode->i_size) {723 const u64 wb_start = ALIGN_DOWN(inode->i_size, bs);724 725 ret = btrfs_cont_expand(BTRFS_I(inode), inode->i_size, destoff);726 if (ret)727 return ret;728 /*729 * We may have truncated the last block if the inode's size is730 * not sector size aligned, so we need to wait for writeback to731 * complete before proceeding further, otherwise we can race732 * with cloning and attempt to increment a reference to an733 * extent that no longer exists (writeback completed right after734 * we found the previous extent covering eof and before we735 * attempted to increment its reference count).736 */737 ret = btrfs_wait_ordered_range(BTRFS_I(inode), wb_start,738 destoff - wb_start);739 if (ret)740 return ret;741 }742 743 /*744 * Lock destination range to serialize with concurrent readahead(), and745 * we are safe from concurrency with relocation of source extents746 * because we have already locked the inode's i_mmap_lock in exclusive747 * mode.748 */749 end = destoff + len - 1;750 lock_extent(&BTRFS_I(inode)->io_tree, destoff, end, &cached_state);751 ret = btrfs_clone(src, inode, off, olen, len, destoff, 0);752 unlock_extent(&BTRFS_I(inode)->io_tree, destoff, end, &cached_state);753 754 /*755 * We may have copied an inline extent into a page of the destination756 * range, so wait for writeback to complete before truncating pages757 * from the page cache. This is a rare case.758 */759 wb_ret = btrfs_wait_ordered_range(BTRFS_I(inode), destoff, len);760 ret = ret ? ret : wb_ret;761 /*762 * Truncate page cache pages so that future reads will see the cloned763 * data immediately and not the previous data.764 */765 truncate_inode_pages_range(&inode->i_data,766 round_down(destoff, PAGE_SIZE),767 round_up(destoff + len, PAGE_SIZE) - 1);768 769 btrfs_btree_balance_dirty(fs_info);770 771 return ret;772}773 774static int btrfs_remap_file_range_prep(struct file *file_in, loff_t pos_in,775 struct file *file_out, loff_t pos_out,776 loff_t *len, unsigned int remap_flags)777{778 struct inode *inode_in = file_inode(file_in);779 struct inode *inode_out = file_inode(file_out);780 u64 bs = BTRFS_I(inode_out)->root->fs_info->sectorsize;781 u64 wb_len;782 int ret;783 784 if (!(remap_flags & REMAP_FILE_DEDUP)) {785 struct btrfs_root *root_out = BTRFS_I(inode_out)->root;786 787 if (btrfs_root_readonly(root_out))788 return -EROFS;789 790 ASSERT(inode_in->i_sb == inode_out->i_sb);791 }792 793 /* Don't make the dst file partly checksummed */794 if ((BTRFS_I(inode_in)->flags & BTRFS_INODE_NODATASUM) !=795 (BTRFS_I(inode_out)->flags & BTRFS_INODE_NODATASUM)) {796 return -EINVAL;797 }798 799 /*800 * Now that the inodes are locked, we need to start writeback ourselves801 * and can not rely on the writeback from the VFS's generic helper802 * generic_remap_file_range_prep() because:803 *804 * 1) For compression we must call filemap_fdatawrite_range() range805 * twice (btrfs_fdatawrite_range() does it for us), and the generic806 * helper only calls it once;807 *808 * 2) filemap_fdatawrite_range(), called by the generic helper only809 * waits for the writeback to complete, i.e. for IO to be done, and810 * not for the ordered extents to complete. We need to wait for them811 * to complete so that new file extent items are in the fs tree.812 */813 if (*len == 0 && !(remap_flags & REMAP_FILE_DEDUP))814 wb_len = ALIGN(inode_in->i_size, bs) - ALIGN_DOWN(pos_in, bs);815 else816 wb_len = ALIGN(*len, bs);817 818 /*819 * Workaround to make sure NOCOW buffered write reach disk as NOCOW.820 *821 * Btrfs' back references do not have a block level granularity, they822 * work at the whole extent level.823 * NOCOW buffered write without data space reserved may not be able824 * to fall back to CoW due to lack of data space, thus could cause825 * data loss.826 *827 * Here we take a shortcut by flushing the whole inode, so that all828 * nocow write should reach disk as nocow before we increase the829 * reference of the extent. We could do better by only flushing NOCOW830 * data, but that needs extra accounting.831 *832 * Also we don't need to check ASYNC_EXTENT, as async extent will be833 * CoWed anyway, not affecting nocow part.834 */835 ret = filemap_flush(inode_in->i_mapping);836 if (ret < 0)837 return ret;838 839 ret = btrfs_wait_ordered_range(BTRFS_I(inode_in), ALIGN_DOWN(pos_in, bs),840 wb_len);841 if (ret < 0)842 return ret;843 ret = btrfs_wait_ordered_range(BTRFS_I(inode_out), ALIGN_DOWN(pos_out, bs),844 wb_len);845 if (ret < 0)846 return ret;847 848 return generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out,849 len, remap_flags);850}851 852static bool file_sync_write(const struct file *file)853{854 if (file->f_flags & (__O_SYNC | O_DSYNC))855 return true;856 if (IS_SYNC(file_inode(file)))857 return true;858 859 return false;860}861 862loff_t btrfs_remap_file_range(struct file *src_file, loff_t off,863 struct file *dst_file, loff_t destoff, loff_t len,864 unsigned int remap_flags)865{866 struct inode *src_inode = file_inode(src_file);867 struct inode *dst_inode = file_inode(dst_file);868 bool same_inode = dst_inode == src_inode;869 int ret;870 871 if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))872 return -EINVAL;873 874 if (same_inode) {875 btrfs_inode_lock(BTRFS_I(src_inode), BTRFS_ILOCK_MMAP);876 } else {877 lock_two_nondirectories(src_inode, dst_inode);878 btrfs_double_mmap_lock(src_inode, dst_inode);879 }880 881 ret = btrfs_remap_file_range_prep(src_file, off, dst_file, destoff,882 &len, remap_flags);883 if (ret < 0 || len == 0)884 goto out_unlock;885 886 if (remap_flags & REMAP_FILE_DEDUP)887 ret = btrfs_extent_same(src_inode, off, len, dst_inode, destoff);888 else889 ret = btrfs_clone_files(dst_file, src_file, off, len, destoff);890 891out_unlock:892 if (same_inode) {893 btrfs_inode_unlock(BTRFS_I(src_inode), BTRFS_ILOCK_MMAP);894 } else {895 btrfs_double_mmap_unlock(src_inode, dst_inode);896 unlock_two_nondirectories(src_inode, dst_inode);897 }898 899 /*900 * If either the source or the destination file was opened with O_SYNC,901 * O_DSYNC or has the S_SYNC attribute, fsync both the destination and902 * source files/ranges, so that after a successful return (0) followed903 * by a power failure results in the reflinked data to be readable from904 * both files/ranges.905 */906 if (ret == 0 && len > 0 &&907 (file_sync_write(src_file) || file_sync_write(dst_file))) {908 ret = btrfs_sync_file(src_file, off, off + len - 1, 0);909 if (ret == 0)910 ret = btrfs_sync_file(dst_file, destoff,911 destoff + len - 1, 0);912 }913 914 return ret < 0 ? ret : len;915}916