diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 9229549697ce7..272eff4441bcf 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -2260,13 +2260,127 @@ bool btrfs_bio_fits_in_ordered_extent(struct page *page, struct bio *bio, return ret; } +/* + * Split an extent_map at [start, start + len] + * + * This function is intended to be used only for extract_ordered_extent(). + */ +static int split_zoned_em(struct btrfs_inode *inode, u64 start, u64 len, + u64 pre, u64 post) +{ + struct extent_map_tree *em_tree = &inode->extent_tree; + struct extent_map *em; + struct extent_map *split_pre = NULL; + struct extent_map *split_mid = NULL; + struct extent_map *split_post = NULL; + int ret = 0; + int modified; + unsigned long flags; + + /* Sanity check */ + if (pre == 0 && post == 0) + return 0; + + split_pre = alloc_extent_map(); + if (pre) + split_mid = alloc_extent_map(); + if (post) + split_post = alloc_extent_map(); + if (!split_pre || (pre && !split_mid) || (post && !split_post)) { + ret = -ENOMEM; + goto out; + } + + ASSERT(pre + post < len); + + lock_extent(&inode->io_tree, start, start + len - 1); + write_lock(&em_tree->lock); + em = lookup_extent_mapping(em_tree, start, len); + if (!em) { + ret = -EIO; + goto out_unlock; + } + + ASSERT(em->len == len); + ASSERT(!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)); + ASSERT(em->block_start < EXTENT_MAP_LAST_BYTE); + + flags = em->flags; + clear_bit(EXTENT_FLAG_PINNED, &em->flags); + clear_bit(EXTENT_FLAG_LOGGING, &flags); + modified = !list_empty(&em->list); + + /* First, replace the em with a new extent_map starting from * em->start */ + split_pre->start = em->start; + split_pre->len = (pre ? pre : em->len - post); + split_pre->orig_start = split_pre->start; + split_pre->block_start = em->block_start; + split_pre->block_len = split_pre->len; + split_pre->orig_block_len = split_pre->block_len; + split_pre->ram_bytes = split_pre->len; + split_pre->flags = flags; + split_pre->compress_type = em->compress_type; + split_pre->generation = em->generation; + + replace_extent_mapping(em_tree, em, split_pre, modified); + + /* + * Now we only have an extent_map at: + * [em->start, em->start + pre] if pre != 0 + * [em->start, em->start + em->len - post] if pre == 0 + */ + + if (pre) { + /* Insert the middle extent_map */ + split_mid->start = em->start + pre; + split_mid->len = em->len - pre - post; + split_mid->orig_start = split_mid->start; + split_mid->block_start = em->block_start + pre; + split_mid->block_len = split_mid->len; + split_mid->orig_block_len = split_mid->block_len; + split_mid->ram_bytes = split_mid->len; + split_mid->flags = flags; + split_mid->compress_type = em->compress_type; + split_mid->generation = em->generation; + add_extent_mapping(em_tree, split_mid, modified); + } + + if (post) { + split_post->start = em->start + em->len - post; + split_post->len = post; + split_post->orig_start = split_post->start; + split_post->block_start = em->block_start + em->len - post; + split_post->block_len = split_post->len; + split_post->orig_block_len = split_post->block_len; + split_post->ram_bytes = split_post->len; + split_post->flags = flags; + split_post->compress_type = em->compress_type; + split_post->generation = em->generation; + add_extent_mapping(em_tree, split_post, modified); + } + + /* Once for us */ + free_extent_map(em); + /* Once for the tree */ + free_extent_map(em); + +out_unlock: + write_unlock(&em_tree->lock); + unlock_extent(&inode->io_tree, start, start + len - 1); +out: + free_extent_map(split_pre); + free_extent_map(split_mid); + free_extent_map(split_post); + + return ret; +} + static blk_status_t extract_ordered_extent(struct btrfs_inode *inode, struct bio *bio, loff_t file_offset) { struct btrfs_ordered_extent *ordered; - struct extent_map *em = NULL, *em_new = NULL; - struct extent_map_tree *em_tree = &inode->extent_tree; u64 start = (u64)bio->bi_iter.bi_sector << SECTOR_SHIFT; + u64 file_len; u64 len = bio->bi_iter.bi_size; u64 end = start + len; u64 ordered_end; @@ -2306,41 +2420,16 @@ static blk_status_t extract_ordered_extent(struct btrfs_inode *inode, goto out; } + file_len = ordered->num_bytes; pre = start - ordered->disk_bytenr; post = ordered_end - end; ret = btrfs_split_ordered_extent(ordered, pre, post); if (ret) goto out; - - read_lock(&em_tree->lock); - em = lookup_extent_mapping(em_tree, ordered->file_offset, len); - if (!em) { - read_unlock(&em_tree->lock); - ret = -EIO; - goto out; - } - read_unlock(&em_tree->lock); - - ASSERT(!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)); - /* - * We cannot reuse em_new here but have to create a new one, as - * unpin_extent_cache() expects the start of the extent map to be the - * logical offset of the file, which does not hold true anymore after - * splitting. - */ - em_new = create_io_em(inode, em->start + pre, len, - em->start + pre, em->block_start + pre, len, - len, len, BTRFS_COMPRESS_NONE, - BTRFS_ORDERED_REGULAR); - if (IS_ERR(em_new)) { - ret = PTR_ERR(em_new); - goto out; - } - free_extent_map(em_new); + ret = split_zoned_em(inode, file_offset, file_len, pre, post); out: - free_extent_map(em); btrfs_put_ordered_extent(ordered); return errno_to_blk_status(ret);