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 "misc.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))

/**
 * Set inode's size according to filesystem options
 *
 * @inode:      inode we want to update the disk_i_size for
 * @new_i_size: 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 btrfs_inode *inode, u64 new_i_size)
{
	struct btrfs_fs_info *fs_info = inode->root->fs_info;
	u64 start, end, i_size;
	int ret;

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

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

/**
 * Mark range within a file as having a new extent inserted
 *
 * @inode: inode being modified
 * @start: start file offset of the file extent we've inserted
 * @len:   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);
}

/**
 * Marks an inode range as not having a backing extent
 *
 * @inode: inode being modified
 * @start: start file offset of the file extent we've inserted
 * @len:   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)