path: root/block/bdev.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 2001  Andrea Arcangeli <andrea@suse.de> SuSE
 *  Copyright (C) 2016 - 2020 Christoph Hellwig
 */

#include <linux/init.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/kmod.h>
#include <linux/major.h>
#include <linux/device_cgroup.h>
#include <linux/blkdev.h>
#include <linux/blk-integrity.h>
#include <linux/backing-dev.h>
#include <linux/module.h>
#include <linux/blkpg.h>
#include <linux/magic.h>
#include <linux/buffer_head.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/mount.h>
#include <linux/pseudo_fs.h>
#include <linux/uio.h>
#include <linux/namei.h>
#include <linux/part_stat.h>
#include <linux/uaccess.h>
#include <linux/stat.h>
#include "../fs/internal.h"
#include "blk.h"

/* Should we allow writing to mounted block devices? */
static bool bdev_allow_write_mounted = IS_ENABLED(CONFIG_BLK_DEV_WRITE_MOUNTED);

struct bdev_inode {
	struct block_device bdev;
	struct inode vfs_inode;
};

static inline struct bdev_inode *BDEV_I(struct inode *inode)
{
	return container_of(inode, struct bdev_inode, vfs_inode);
}

struct block_device *I_BDEV(struct inode *inode)
{
	return &BDEV_I(inode)->bdev;
}
EXPORT_SYMBOL(I_BDEV);

static void bdev_write_inode(struct block_device *bdev)
{
	struct inode *inode = bdev->bd_inode;
	int ret;

	spin_lock(&inode->i_lock);
	while (inode->i_state & I_DIRTY) {
		spin_unlock(&inode->i_lock);
		ret = write_inode_now(inode, true);
		if (ret)
			pr_warn_ratelimited(
	"VFS: Dirty inode writeback failed for block device %pg (err=%d).\n",
				bdev, ret);
		spin_lock(&inode->i_lock);
	}
	spin_unlock(&inode->i_lock);
}

/* Kill _all_ buffers and pagecache , dirty or not.. */
static void kill_bdev(struct block_device *bdev)
{
	struct address_space *mapping = bdev->bd_inode->i_mapping;

	if (mapping_empty(mapping))
		return;

	invalidate_bh_lrus();
	truncate_inode_pages(mapping, 0);
}

/* Invalidate clean unused buffers and pagecache. */
void invalidate_bdev(struct block_device *bdev)
{
	struct address_space *mapping = bdev->bd_inode->i_mapping;

	if (mapping->nrpages) {
		invalidate_bh_lrus();
		lru_add_drain_all();	/* make sure all lru add caches are flushed */
		invalidate_mapping_pages(mapping, 0, -1);
	}
}
EXPORT_SYMBOL(invalidate_bdev);

/*
 * Drop all buffers & page cache for given bdev range. This function bails
 * with error if bdev has other exclusive owner (such as filesystem).
 */
int truncate_bdev_range(struct block_device *bdev, blk_mode_t mode,
			loff_t lstart, loff_t lend)
{
	/*
	 * If we don't hold exclusive handle for the device, upgrade to it
	 * while we discard the buffer cache to avoid discarding buffers
	 * under live filesystem.
	 */
	if (!(mode & BLK_OPEN_EXCL)) {
		int err = bd_prepare_to_claim(bdev, truncate_bdev_range, NULL);
		if (err)
			goto invalidate;
	}

	truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend);
	if (!(mode & BLK_OPEN_EXCL))
		bd_abort_claiming(bdev, truncate_bdev_range);
	return 0;

invalidate:
	/*
	 * Someone else has handle exclusively open. Try invalidating instead.
	 * The 'end' argument is inclusive so the rounding is safe.
	 */
	return invalidate_inode_pages2_range(bdev->bd_inode->i_mapping,
					     lstart >> PAGE_SHIFT,
					     lend >> PAGE_SHIFT);
}

static void set_init_blocksize(struct block_device *bdev)
{
	unsigned int bsize = bdev_logical_block_size(bdev);
	loff_t size = i_size_read(bdev->bd_inode);

	while (bsize < PAGE_SIZE) {
		if (size & bsize)
			break;
		bsize <<= 1;
	}
	bdev->bd_inode->i_blkbits = blksize_bits(bsize);
}

int set_blocksize(struct block_device *bdev, int size)
{
	/* Size must be a power of two, and between 512 and PAGE_SIZE */
	if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size))
		return -EINVAL;

	/* Size cannot be smaller than the size supported by the device */
	if (size < bdev_logical_block_size(bdev))
		return -EINVAL;

	/* Don't change the size if it is same as current */
	if (bdev->bd_inode->i_blkbits != blksize_bits(size)) {
		sync_blockdev(bdev);
		bdev->bd_inode->i_blkbits = blksize_bits(size);
		kill_bdev(bdev);