path: root/fs/ext4/ioctl.c

// SPDX-License-Identifier: GPL-2.0
/*
 * linux/fs/ext4/ioctl.c
 *
 * Copyright (C) 1993, 1994, 1995
 * Remy Card (card@masi.ibp.fr)
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 */

#include <linux/fs.h>
#include <linux/capability.h>
#include <linux/time.h>
#include <linux/compat.h>
#include <linux/mount.h>
#include <linux/file.h>
#include <linux/quotaops.h>
#include <linux/random.h>
#include <linux/uuid.h>
#include <linux/uaccess.h>
#include <linux/delay.h>
#include <linux/iversion.h>
#include <linux/fileattr.h>
#include "ext4_jbd2.h"
#include "ext4.h"
#include <linux/fsmap.h>
#include "fsmap.h"
#include <trace/events/ext4.h>

typedef void ext4_update_sb_callback(struct ext4_super_block *es,
				       const void *arg);

/*
 * Superblock modification callback function for changing file system
 * label
 */
static void ext4_sb_setlabel(struct ext4_super_block *es, const void *arg)
{
	/* Sanity check, this should never happen */
	BUILD_BUG_ON(sizeof(es->s_volume_name) < EXT4_LABEL_MAX);

	memcpy(es->s_volume_name, (char *)arg, EXT4_LABEL_MAX);
}

static
int ext4_update_primary_sb(struct super_block *sb, handle_t *handle,
			   ext4_update_sb_callback func,
			   const void *arg)
{
	int err = 0;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	struct buffer_head *bh = sbi->s_sbh;
	struct ext4_super_block *es = sbi->s_es;

	trace_ext4_update_sb(sb, bh->b_blocknr, 1);

	BUFFER_TRACE(bh, "get_write_access");
	err = ext4_journal_get_write_access(handle, sb,
					    bh,
					    EXT4_JTR_NONE);
	if (err)
		goto out_err;

	lock_buffer(bh);
	func(es, arg);
	ext4_superblock_csum_set(sb);
	unlock_buffer(bh);

	if (buffer_write_io_error(bh) || !buffer_uptodate(bh)) {
		ext4_msg(sbi->s_sb, KERN_ERR, "previous I/O error to "
			 "superblock detected");
		clear_buffer_write_io_error(bh);
		set_buffer_uptodate(bh);
	}

	err = ext4_handle_dirty_metadata(handle, NULL, bh);
	if (err)
		goto out_err;
	err = sync_dirty_buffer(bh);
out_err:
	ext4_std_error(sb, err);
	return err;
}

/*
 * Update one backup superblock in the group 'grp' using the callback
 * function 'func' and argument 'arg'. If the handle is NULL the
 * modification is not journalled.
 *
 * Returns: 0 when no modification was done (no superblock in the group)
 *	    1 when the modification was successful
 *	   <0 on error
 */
static int ext4_update_backup_sb(struct super_block *sb,
				 handle_t *handle, ext4_group_t grp,
				 ext4_update_sb_callback func, const void *arg)
{
	int err = 0;
	ext4_fsblk_t sb_block;
	struct buffer_head *bh;
	unsigned long offset = 0;
	struct ext4_super_block *es;

	if (!ext4_bg_has_super(sb, grp))
		return 0;

	/*
	 * For the group 0 there is always 1k padding, so we have
	 * either adjust offset, or sb_block depending on blocksize
	 */
	if (grp == 0) {
		sb_block = 1 * EXT4_MIN_BLOCK_SIZE;
		offset = do_div(sb_block, sb->s_blocksize);
	} else {
		sb_block = ext4_group_first_block_no(sb, grp);
		offset = 0;
	}

	trace_ext4_update_sb(sb, sb_block, hand