path: root/fs/ext4/ialloc.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/ext4/ialloc.c
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card (card@masi.ibp.fr)
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 *  BSD ufs-inspired inode and directory allocation by
 *  Stephen Tweedie (sct@redhat.com), 1993
 *  Big-endian to little-endian byte-swapping/bitmaps by
 *        David S. Miller (davem@caip.rutgers.edu), 1995
 */

#include <linux/time.h>
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/quotaops.h>
#include <linux/buffer_head.h>
#include <linux/random.h>
#include <linux/bitops.h>
#include <linux/blkdev.h>
#include <linux/cred.h>

#include <asm/byteorder.h>

#include "ext4.h"
#include "ext4_jbd2.h"
#include "xattr.h"
#include "acl.h"

#include <trace/events/ext4.h>

/*
 * ialloc.c contains the inodes allocation and deallocation routines
 */

/*
 * The free inodes are managed by bitmaps.  A file system contains several
 * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
 * block for inodes, N blocks for the inode table and data blocks.
 *
 * The file system contains group descriptors which are located after the
 * super block.  Each descriptor contains the number of the bitmap block and
 * the free blocks count in the block.
 */

/*
 * To avoid calling the atomic setbit hundreds or thousands of times, we only
 * need to use it within a single byte (to ensure we get endianness right).
 * We can use memset for the rest of the bitmap as there are no other users.
 */
void ext4_mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
{
	int i;

	if (start_bit >= end_bit)
		return;

	ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
	for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
		ext4_set_bit(i, bitmap);
	if (i < end_bit)
		memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
}

void ext4_end_bitmap_read(struct buffer_head *bh, int uptodate)
{
	if (uptodate) {
		set_buffer_uptodate(bh);
		set_bitmap_uptodate(bh);
	}
	unlock_buffer(bh);
	put_bh(bh);
}

static int ext4_validate_inode_bitmap(struct super_block *sb,
				      struct ext4_group_desc *desc,
				      ext4_group_t block_group,
				      struct buffer_head *bh)
{
	ext4_fsblk_t	blk;
	struct ext4_group_info *grp;

	if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY)
		return 0;

	if (buffer_verified(bh))
		return 0;

	grp = ext4_get_group_info(sb, block_group);
	if (!grp || EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
		return -EFSCORRUPTED;

	ext4_lock_group(sb, block_group);
	if (buffer_verified(bh))
		goto verified;
	blk = ext4_inode_bitmap(sb, desc);
	if (!ext4_inode_bitmap_csum_verify(sb, desc, bh) ||
	    ext4_simulate_fail(sb, EXT4_SIM_IBITMAP_CRC)) {
		ext4_unlock_group(sb, block_group);
		ext4_error(sb, "Corrupt inode bitmap - block_group = %u, "
			   "inode_bitmap = %llu", block_group, blk);
		ext4_mark_group_bitmap_corrupted(sb, block_group,
					EXT4_GROUP_INFO_IBITMAP_CORRUPT);
		return -EFSBADCRC;
	}
	set_buffer_verified(bh);
verified:
	ext4_unlock_group(sb, block_group);
	return 0;
}

/*
 * Read the inode allocation bitmap for a given block_group, reading
 * into the specified slot in the superblock's bitmap cache.
 *
 * Return buffer_head of bitmap on success, or an ERR_PTR on error.
 */
static struct buffer_head *
ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
{
	struct ext4_group_desc *desc;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	struct buffer_head *bh = NULL;
	ext4_fsblk_t bitmap_blk;
	int err;

	desc = ext4_get_group_desc(sb, block_group, NULL);
	if (!desc)
		return ERR_PTR(-EFSCORRUPTED);

	bitmap_blk = ext4_inode_bitmap(sb, desc);
	if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
	    (bitmap_blk >= ext4_blocks_count(sbi->s_es))) {
		ext4_error(sb, "Invalid inode bitmap blk %llu in "
			   "block_group %u", bitmap_blk, block_group);
		ext4_mark_group_bitmap_corrupted(sb, block_group,
					EXT4_GROUP_INFO_IBITMAP_CORRUPT);
		return ERR_PTR(-EFSCORRUPTED);
	}
	bh = sb_getblk(sb, bitmap_blk);
	if (unlikely(!bh)) {
		ext4_warning(sb, "Cannot read inode bitmap - "
			     "block_group = %u, inode_bitmap = %llu",
			     block_group, bitmap_blk);
		return ERR_PTR(-ENOMEM);
	}
	if (bitmap_uptodate(bh))
		goto verify;

	lock_buffer(bh);
	if (bitmap_uptodate(bh)) {
		unlock_buffer(bh);
		goto verify;
	}

	ext4_lock_group(sb, block_group);
	if (ext4_has_group_desc_csum(sb) &&
	    (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT))) {
		if (block_group == 0) {
			ext4_unlock_group(sb, block_group);
			unlock_buffer(bh);
			ext4_error(sb, "Inode bitmap for bg 0 marked "
				   "uninitialized");