path: root/fs/btrfs/file-item.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 */

#include <linux/bio.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/sched/mm.h>
#include <crypto/hash.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "volumes.h"
#include "print-tree.h"
#include "compression.h"

#define __MAX_CSUM_ITEMS(r, size) ((unsigned long)(((BTRFS_LEAF_DATA_SIZE(r) - \
				   sizeof(struct btrfs_item) * 2) / \
				  size) - 1))

#define MAX_CSUM_ITEMS(r, size) (min_t(u32, __MAX_CSUM_ITEMS(r, size), \
				       PAGE_SIZE))

/**
 * @inode - the inode we want to update the disk_i_size for
 * @new_i_size - the i_size we want to set to, 0 if we use i_size
 *
 * With NO_HOLES set this simply sets the disk_is_size to whatever i_size_read()
 * returns as it is perfectly fine with a file that has holes without hole file
 * extent items.
 *
 * However without NO_HOLES we need to only return the area that is contiguous
 * from the 0 offset of the file.  Otherwise we could end up adjust i_size up
 * to an extent that has a gap in between.
 *
 * Finally new_i_size should only be set in the case of truncate where we're not
 * ready to use i_size_read() as the limiter yet.
 */
void btrfs_inode_safe_disk_i_size_write(struct inode *inode, u64 new_i_size)
{
	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
	u64 start, end, i_size;
	int ret;

	i_size = new_i_size ?: i_size_read(inode);
	if (btrfs_fs_incompat(fs_info, NO_HOLES)) {
		BTRFS_I(inode)->disk_i_size = i_size;
		return;
	}

	spin_lock(&BTRFS_I(inode)->lock);
	ret = find_contiguous_extent_bit(&BTRFS_I(inode)->file_extent_tree, 0,
					 &start, &end, EXTENT_DIRTY);
	if (!ret && start == 0)
		i_size = min(i_size, end + 1);
	else
		i_size = 0;
	BTRFS_I(inode)->disk_i_size = i_size;
	spin_unlock(&BTRFS_I(inode)->lock);
}

/**
 * @inode - the inode we're modifying
 * @start - the start file offset of the file extent we've inserted
 * @len - the logical length of the file extent item
 *
 * Call when we are inserting a new file extent where there was none before.
 * Does not need to call this in the case where we're replacing an existing file
 * extent, however if not sure it's fine to call this multiple times.
 *
 * The start and len must match the file extent item, so thus must be sectorsize
 * aligned.
 */
int btrfs_inode_set_file_extent_range(struct btrfs_inode *inode, u64 start,
				      u64 len)
{
	if (len == 0)
		return 0;

	ASSERT(IS_ALIGNED(start + len, inode->root->fs_info->sectorsize));

	if (btrfs_fs_incompat(inode->root->fs_info, NO_HOLES))
		return 0;
	return set_extent_bits(&inode->file_extent_tree, start, start + len - 1,
			       EXTENT_DIRTY);
}

/**
 * @inode - the inode we're modifying
 * @start - the start file offset of the file extent we've inserted
 * @len - the logical length of the file extent item
 *
 * Called when we drop a file extent, for example when we truncate.  Doesn't
 * need to be called for cases where we're replacing a file extent, like when
 * we've COWed a file extent.
 *
 * The start and len must match the file extent item, so thus must be sectorsize
 * aligned.
 */
int btrfs_inode_clear_file_extent_range(struct btrfs_inode *inode, u64 start,
					u64 len)
{
	if (len == 0)
		return 0;

	ASSERT(IS_ALIGNED(start + len, inode->root->fs_info->sectorsize) ||
	       len == (u64)-1);

	if (btrfs_fs_incompat(inode->root->fs_info, NO_HOLES))
		return 0;
	return clear_extent_bit(&inode->file_extent_tree, start,
				start + len - 1, EXTENT_DIRTY, 0, 0, NULL);
}

static inline u32 max_ordered_sum_bytes(struct btrfs_fs_info *fs_info,
					u16 csum_size)
{
	u32 ncsums = (PAGE_SIZE - sizeof(struct btrfs_ordered_sum)) / csum_size;

	return ncsums * fs_info->sectorsize;
}

int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
			     struct btrfs_root *root,
			     u64 objectid, u64 pos,
			     u64 disk_offset, u64 disk_num_bytes,
			     u64 num_bytes, u64 offset, u64 ram_bytes,
			     u8 compression, u8 encryption, u16 other_encoding)
{
	int ret = 0;
	struct btrfs_file_extent_item *item;
	struct btrfs_key file_key;
	struct btrfs_path *path;
	struct extent_buffer *leaf;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;
	file_key.objectid = objectid;
	file_key.offset = pos;
	file_key.type = BTRFS_EXTENT_DATA_KEY;

	path->leave_spinning = 1;
	ret = btrfs_insert_empty_item(trans, root, path, &file_key,
				      sizeof(*item));
	if (ret < 0)
		goto out;
	BUG_ON(ret); /* Can't happen */
	leaf = path->nodes[0];
	item = btrfs_item_ptr(leaf, path->slots<