text: /*
   * 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/jbd2.h>
  #include <linux/capability.h>
  #include <linux/time.h>
  #include <linux/compat.h>
  #include <linux/mount.h>
  #include <linux/file.h>
  #include <asm/uaccess.h>
  #include "ext4_jbd2.h"
  #include "ext4.h"
  
  #define MAX_32_NUM ((((unsigned long long) 1) << 32) - 1)
  
  /**
   * Swap memory between @a and @b for @len bytes.
   *
   * @a:          pointer to first memory area
   * @b:          pointer to second memory area
   * @len:        number of bytes to swap
   *
   */
  static void memswap(void *a, void *b, size_t len)
  {
  	unsigned char *ap, *bp;
  	unsigned char tmp;
  
  	ap = (unsigned char *)a;
  	bp = (unsigned char *)b;
  	while (len-- > 0) {
  		tmp = *ap;
  		*ap = *bp;
  		*bp = tmp;
  		ap++;
  		bp++;
  	}
  }
  
  /**
   * Swap i_data and associated attributes between @inode1 and @inode2.
   * This function is used for the primary swap between inode1 and inode2
   * and also to revert this primary swap in case of errors.
   *
   * Therefore you have to make sure, that calling this method twice
   * will revert all changes.
   *
   * @inode1:     pointer to first inode
   * @inode2:     pointer to second inode
   */
  static void swap_inode_data(struct inode *inode1, struct inode *inode2)
  {
  	loff_t isize;
  	struct ext4_inode_info *ei1;
  	struct ext4_inode_info *ei2;
  
  	ei1 = EXT4_I(inode1);
  	ei2 = EXT4_I(inode2);
  
  	memswap(&inode1->i_flags, &inode2->i_flags, sizeof(inode1->i_flags));
  	memswap(&inode1->i_version, &inode2->i_version,
  		  sizeof(inode1->i_version));
  	memswap(&inode1->i_blocks, &inode2->i_blocks,
  		  sizeof(inode1->i_blocks));
  	memswap(&inode1->i_bytes, &inode2->i_bytes, sizeof(inode1->i_bytes));
  	memswap(&inode1->i_atime, &inode2->i_atime, sizeof(inode1->i_atime));
  	memswap(&inode1->i_mtime, &inode2->i_mtime, sizeof(inode1->i_mtime));
  
  	memswap(ei1->i_data, ei2->i_data, sizeof(ei1->i_data));
  	memswap(&ei1->i_flags, &ei2->i_flags, sizeof(ei1->i_flags));
  	memswap(&ei1->i_disksize, &ei2->i_disksize, sizeof(ei1->i_disksize));
  	ext4_es_remove_extent(inode1, 0, EXT_MAX_BLOCKS);
  	ext4_es_remove_extent(inode2, 0, EXT_MAX_BLOCKS);
  	ext4_es_lru_del(inode1);
  	ext4_es_lru_del(inode2);
  
  	isize = i_size_read(inode1);
  	i_size_write(inode1, i_size_read(inode2));
  	i_size_write(inode2, isize);
  }
  
  /**
   * Swap the information from the given @inode and the inode
   * EXT4_BOOT_LOADER_INO. It will basically swap i_data and all other
   * important fields of the inodes.
   *
   * @sb:         the super block of the filesystem
   * @inode:      the inode to swap with EXT4_BOOT_LOADER_INO
   *
   */
  static long swap_inode_boot_loader(struct super_block *sb,
  				struct inode *inode)
  {
  	handle_t *handle;
  	int err;
  	struct inode *inode_bl;
  	struct ext4_inode_info *ei_bl;
  	struct ext4_sb_info *sbi = EXT4_SB(sb);
  
  	if (inode->i_nlink != 1 || !S_ISREG(inode->i_mode))
  		return -EINVAL;
  
  	if (!inode_owner_or_capable(inode) || !capable(CAP_SYS_ADMIN))
  		return -EPERM;
  
  	inode_bl = ext4_iget(sb, EXT4_BOOT_LOADER_INO);
  	if (IS_ERR(inode_bl))
  		return PTR_ERR(inode_bl);
  	ei_bl = EXT4_I(inode_bl);
  
  	filemap_flush(inode->i_mapping);
  	filemap_flush(inode_bl->i_mapping);
  
  	/* Protect orig inodes against a truncate and make sure,
  	 * that only 1 swap_inode_boot_loader is running. */
  	lock_two_nondirectories(inode, inode_bl);
  
  	truncate_inode_pages(&inode->i_data, 0);
  	truncate_inode_pages(&inode_bl->i_data, 0);
  
  	/* Wait for all existing dio workers */
  	ext4_inode_block_unlocked_dio(inode);
  	ext4_inode_block_unlocked_dio(inode_bl);
  	inode_dio_wait(inode);
  	inode_dio_wait(inode_bl);
  
  	handle = ext4_journal_start(inode_bl, EXT4_HT_MOVE_EXTENTS, 2);
  	if (IS_ERR(handle)) {
  		err = -EINVAL;
  		goto journal_err_out;
  	}
  
  	/* Protect extent tree against block allocations via delalloc */
  	ext4_double_down_write_data_sem(inode, inode_bl);
  
  	if (inode_bl->i_nlink == 0) {
  		/* this inode has never been used as a BOOT_LOADER */
  		set_nlink(inode_bl, 1);
  		i_uid_write(inode_bl, 0);
  		i_gid_write(inode_bl, 0);
  		inode_bl->i_flags = 0;
  		ei_bl->i_flags = 0;
  		inode_bl->i_version = 1;
  		i_size_write(inode_bl, 0);
  		inode_bl->i_mode = S_IFREG;
  		if (EXT4_HAS_INCOMPAT_FEATURE(sb,
  					      EXT4_FEATURE_INCOMPAT_EXTENTS)) {
  			ext4_set_inode_flag(inode_bl, EXT4_INODE_EXTENTS);
  			ext4_ext_tree_init(handle, inode_bl);
  		} else
  			memset(ei_bl->i_data, 0, sizeof(ei_bl->i_data));
  	}
  
  	swap_inode_data(inode, inode_bl);
  
  	inode->i_ctime = inode_bl->i_ctime = ext4_current_time(inode);
  
  	spin_lock(&sbi->s_next_gen_lock);
  	inode->i_generation = sbi->s_next_generation++;
  	inode_bl->i_generation = sbi->s_next_generation++;
  	spin_unlock(&sbi->s_next_gen_lock);
  
  	ext4_discard_preallocations(inode);
  
  	err = ext4_mark_inode_dirty(handle, inode);
  	if (err < 0) {
  		ext4_warning(inode->i_sb,
  			"couldn't mark inode #%lu dirty (err %d)",
  			inode->i_ino, err);
  		/* Revert all changes: */
  		swap_inode_data(inode, inode_bl);
  	} else {
  		err = ext4_mark_inode_dirty(handle, inode_bl);
  		if (err < 0) {
  			ext4_warning(inode_bl->i_sb,
  				"couldn't mark inode #%lu dirty (err %d)",
  				inode_bl->i_ino, err);
  			/* Revert all changes: */
  			swap_inode_data(inode, inode_bl);
  			ext4_mark_inode_dirty(handle, inode);
  		}
  	}
  	ext4_journal_stop(handle);
  	ext4_double_up_write_data_sem(inode, inode_bl);
  
  journal_err_out:
  	ext4_inode_resume_unlocked_dio(inode);
  	ext4_inode_resume_unlocked_dio(inode_bl);
  	unlock_two_nondirectories(inode, inode_bl);
  	iput(inode_bl);
  	return err;
  }
  
  long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
  {
  	struct inode *inode = file_inode(filp);
  	struct super_block *sb = inode->i_sb;
  	struct ext4_inode_info *ei = EXT4_I(inode);
  	unsigned int flags;
  
  	ext4_debug("cmd = %u, arg = %lu\n", cmd, arg);
  
  	switch (cmd) {
  	case EXT4_IOC_GETFLAGS:
  		ext4_get_inode_flags(ei);
  		flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
  		return put_user(flags, (int __user *) arg);
  	case EXT4_IOC_SETFLAGS: {
  		handle_t *handle = NULL;
  		int err, migrate = 0;
  		struct ext4_iloc iloc;
  		unsigned int oldflags, mask, i;
  		unsigned int jflag;
  
  		if (!inode_owner_or_capable(inode))
  			return -EACCES;
  
  		if (get_user(flags, (int __user *) arg))
  			return -EFAULT;
  
  		err = mnt_want_write_file(filp);
  		if (err)
  			return err;
  
  		flags = ext4_mask_flags(inode->i_mode, flags);
  
  		err = -EPERM;
  		mutex_lock(&inode->i_mutex);
  		/* Is it quota file? Do not allow user to mess with it */
  		if (IS_NOQUOTA(inode))
  			goto flags_out;
  
  		oldflags = ei->i_flags;
  
  		/* The JOURNAL_DATA flag is modifiable only by root */
  		jflag = flags & EXT4_JOURNAL_DATA_FL;
  
  		/*
  		 * The IMMUTABLE and APPEND_ONLY flags can only be changed by
  		 * the relevant capability.
  		 *
  		 * This test looks nicer. Thanks to Pauline Middelink
  		 */
  		if ((flags ^ oldflags) & (EXT4_APPEND_FL | EXT4_IMMUTABLE_FL)) {
  			if (!capable(CAP_LINUX_IMMUTABLE))
  				goto flags_out;
  		}
  
  		/*
  		 * The JOURNAL_DATA flag can only be changed by
  		 * the relevant capability.
  		 */
  		if ((jflag ^ oldflags) & (EXT4_JOURNAL_DATA_FL)) {
  			if (!capable(CAP_SYS_RESOURCE))
  				goto flags_out;
  		}
  		if ((flags ^ oldflags) & EXT4_EXTENTS_FL)
  			migrate = 1;
  
  		if (flags & EXT4_EOFBLOCKS_FL) {
  			/* we don't support adding EOFBLOCKS flag */
  			if (!(oldflags & EXT4_EOFBLOCKS_FL)) {
  				err = -EOPNOTSUPP;
  				goto flags_out;
  			}
  		} else if (oldflags & EXT4_EOFBLOCKS_FL)
  			ext4_truncate(inode);
  
  		handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
  		if (IS_ERR(handle)) {
  			err = PTR_ERR(handle);
  			goto flags_out;
  		}
  		if (IS_SYNC(inode))
  			ext4_handle_sync(handle);
  		err = ext4_reserve_inode_write(handle, inode, &iloc);
  		if (err)
  			goto flags_err;
  
  		for (i = 0, mask = 1; i < 32; i++, mask <<= 1) {
  			if (!(mask & EXT4_FL_USER_MODIFIABLE))
  				continue;
  			if (mask & flags)
  				ext4_set_inode_flag(inode, i);
  			else
  				ext4_clear_inode_flag(inode, i);
  		}
  
  		ext4_set_inode_flags(inode);
  		inode->i_ctime = ext4_current_time(inode);
  
  		err = ext4_mark_iloc_dirty(handle, inode, &iloc);
  flags_err:
  		ext4_journal_stop(handle);
  		if (err)
  			goto flags_out;
  
  		if ((jflag ^ oldflags) & (EXT4_JOURNAL_DATA_FL))
  			err = ext4_change_inode_journal_flag(inode, jflag);
  		if (err)
  			goto flags_out;
  		if (migrate) {
  			if (flags & EXT4_EXTENTS_FL)
  				err = ext4_ext_migrate(inode);
  			else
  				err = ext4_ind_migrate(inode);
  		}
  
  flags_out:
  		mutex_unlock(&inode->i_mutex);
  		mnt_drop_write_file(filp);
  		return err;
  	}
  	case EXT4_IOC_GETVERSION:
  	case EXT4_IOC_GETVERSION_OLD:
  		return put_user(inode->i_generation, (int __user *) arg);
  	case EXT4_IOC_SETVERSION:
  	case EXT4_IOC_SETVERSION_OLD: {
  		handle_t *handle;
  		struct ext4_iloc iloc;
  		__u32 generation;
  		int err;
  
  		if (!inode_owner_or_capable(inode))
  			return -EPERM;
  
  		if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
  				EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
  			ext4_warning(sb, "Setting inode version is not "
  				     "supported with metadata_csum enabled.");
  			return -ENOTTY;
  		}
  
  		err = mnt_want_write_file(filp);
  		if (err)
  			return err;
  		if (get_user(generation, (int __user *) arg)) {
  			err = -EFAULT;
  			goto setversion_out;
  		}
  
  		mutex_lock(&inode->i_mutex);
  		handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
  		if (IS_ERR(handle)) {
  			err = PTR_ERR(handle);
  			goto unlock_out;
  		}
  		err = ext4_reserve_inode_write(handle, inode, &iloc);
  		if (err == 0) {
  			inode->i_ctime = ext4_current_time(inode);
  			inode->i_generation = generation;
  			err = ext4_mark_iloc_dirty(handle, inode, &iloc);
  		}
  		ext4_journal_stop(handle);
  
  unlock_out:
  		mutex_unlock(&inode->i_mutex);
  setversion_out:
  		mnt_drop_write_file(filp);
  		return err;
  	}
  	case EXT4_IOC_GROUP_EXTEND: {
  		ext4_fsblk_t n_blocks_count;
  		int err, err2=0;
  
  		err = ext4_resize_begin(sb);
  		if (err)
  			return err;
  
  		if (get_user(n_blocks_count, (__u32 __user *)arg)) {
  			err = -EFAULT;
  			goto group_extend_out;
  		}
  
  		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
  			       EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
  			ext4_msg(sb, KERN_ERR,
  				 "Online resizing not supported with bigalloc");
  			err = -EOPNOTSUPP;
  			goto group_extend_out;
  		}
  
  		err = mnt_want_write_file(filp);
  		if (err)
  			goto group_extend_out;
  
  		err = ext4_group_extend(sb, EXT4_SB(sb)->s_es, n_blocks_count);
  		if (EXT4_SB(sb)->s_journal) {
  			jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
  			err2 = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
  			jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
  		}
  		if (err == 0)
  			err = err2;
  		mnt_drop_write_file(filp);
  group_extend_out:
  		ext4_resize_end(sb);
  		return err;
  	}
  
  	case EXT4_IOC_MOVE_EXT: {
  		struct move_extent me;
  		struct fd donor;
  		int err;
  
  		if (!(filp->f_mode & FMODE_READ) ||
  		    !(filp->f_mode & FMODE_WRITE))
  			return -EBADF;
  
  		if (copy_from_user(&me,
  			(struct move_extent __user *)arg, sizeof(me)))
  			return -EFAULT;
  		me.moved_len = 0;
  
  		donor = fdget(me.donor_fd);
  		if (!donor.file)
  			return -EBADF;
  
  		if (!(donor.file->f_mode & FMODE_WRITE)) {
  			err = -EBADF;
  			goto mext_out;
  		}
  
  		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
  			       EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
  			ext4_msg(sb, KERN_ERR,
  				 "Online defrag not supported with bigalloc");
  			err = -EOPNOTSUPP;
  			goto mext_out;
  		}
  
  		err = mnt_want_write_file(filp);
  		if (err)
  			goto mext_out;
  
  		err = ext4_move_extents(filp, donor.file, me.orig_start,
  					me.donor_start, me.len, &me.moved_len);
  		mnt_drop_write_file(filp);
  
  		if (copy_to_user((struct move_extent __user *)arg,
  				 &me, sizeof(me)))
  			err = -EFAULT;
  mext_out:
  		fdput(donor);
  		return err;
  	}
  
  	case EXT4_IOC_GROUP_ADD: {
  		struct ext4_new_group_data input;
  		int err, err2=0;
  
  		err = ext4_resize_begin(sb);
  		if (err)
  			return err;
  
  		if (copy_from_user(&input, (struct ext4_new_group_input __user *)arg,
  				sizeof(input))) {
  			err = -EFAULT;
  			goto group_add_out;
  		}
  
  		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
  			       EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
  			ext4_msg(sb, KERN_ERR,
  				 "Online resizing not supported with bigalloc");
  			err = -EOPNOTSUPP;
  			goto group_add_out;
  		}
  
  		err = mnt_want_write_file(filp);
  		if (err)
  			goto group_add_out;
  
  		err = ext4_group_add(sb, &input);
  		if (EXT4_SB(sb)->s_journal) {
  			jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
  			err2 = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
  			jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
  		}
  		if (err == 0)
  			err = err2;
  		mnt_drop_write_file(filp);
  		if (!err && ext4_has_group_desc_csum(sb) &&
  		    test_opt(sb, INIT_INODE_TABLE))
  			err = ext4_register_li_request(sb, input.group);
  group_add_out:
  		ext4_resize_end(sb);
  		return err;
  	}
  
  	case EXT4_IOC_MIGRATE:
  	{
  		int err;
  		if (!inode_owner_or_capable(inode))
  			return -EACCES;
  
  		err = mnt_want_write_file(filp);
  		if (err)
  			return err;
  		/*
  		 * inode_mutex prevent write and truncate on the file.
  		 * Read still goes through. We take i_data_sem in
  		 * ext4_ext_swap_inode_data before we switch the
  		 * inode format to prevent read.
  		 */
  		mutex_lock(&(inode->i_mutex));
  		err = ext4_ext_migrate(inode);
  		mutex_unlock(&(inode->i_mutex));
  		mnt_drop_write_file(filp);
  		return err;
  	}
  
  	case EXT4_IOC_ALLOC_DA_BLKS:
  	{
  		int err;
  		if (!inode_owner_or_capable(inode))
  			return -EACCES;
  
  		err = mnt_want_write_file(filp);
  		if (err)
  			return err;
  		err = ext4_alloc_da_blocks(inode);
  		mnt_drop_write_file(filp);
  		return err;
  	}
  
  	case EXT4_IOC_SWAP_BOOT:
  		if (!(filp->f_mode & FMODE_WRITE))
  			return -EBADF;
  		return swap_inode_boot_loader(sb, inode);
  
  	case EXT4_IOC_RESIZE_FS: {
  		ext4_fsblk_t n_blocks_count;
  		int err = 0, err2 = 0;
  		ext4_group_t o_group = EXT4_SB(sb)->s_groups_count;
  
  		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
  			       EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
  			ext4_msg(sb, KERN_ERR,
  				 "Online resizing not (yet) supported with bigalloc");
  			return -EOPNOTSUPP;
  		}
  
  		if (copy_from_user(&n_blocks_count, (__u64 __user *)arg,
  				   sizeof(__u64))) {
  			return -EFAULT;
  		}
  
  		err = ext4_resize_begin(sb);
  		if (err)
  			return err;
  
  		err = mnt_want_write_file(filp);
  		if (err)
  			goto resizefs_out;
  
  		err = ext4_resize_fs(sb, n_blocks_count);
  		if (EXT4_SB(sb)->s_journal) {
  			jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
  			err2 = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
  			jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
  		}
  		if (err == 0)
  			err = err2;
  		mnt_drop_write_file(filp);
  		if (!err && (o_group > EXT4_SB(sb)->s_groups_count) &&
  		    ext4_has_group_desc_csum(sb) &&
  		    test_opt(sb, INIT_INODE_TABLE))
  			err = ext4_register_li_request(sb, o_group);
  
  resizefs_out:
  		ext4_resize_end(sb);
  		return err;
  	}
  
  	case FITRIM:
  	{
  		struct request_queue *q = bdev_get_queue(sb->s_bdev);
  		struct fstrim_range range;
  		int ret = 0;
  
  		if (!capable(CAP_SYS_ADMIN))
  			return -EPERM;
  
  		if (!blk_queue_discard(q))
  			return -EOPNOTSUPP;
  
  		if (copy_from_user(&range, (struct fstrim_range __user *)arg,
  		    sizeof(range)))
  			return -EFAULT;
  
  		range.minlen = max((unsigned int)range.minlen,
  				   q->limits.discard_granularity);
  		ret = ext4_trim_fs(sb, &range);
  		if (ret < 0)
  			return ret;
  
  		if (copy_to_user((struct fstrim_range __user *)arg, &range,
  		    sizeof(range)))
  			return -EFAULT;
  
  		return 0;
  	}
  	case EXT4_IOC_PRECACHE_EXTENTS:
  		return ext4_ext_precache(inode);
  
  	default:
  		return -ENOTTY;
  	}
  }
  
  #ifdef CONFIG_COMPAT
  long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
  {
  	/* These are just misnamed, they actually get/put from/to user an int */
  	switch (cmd) {
  	case EXT4_IOC32_GETFLAGS:
  		cmd = EXT4_IOC_GETFLAGS;
  		break;
  	case EXT4_IOC32_SETFLAGS:
  		cmd = EXT4_IOC_SETFLAGS;
  		break;
  	case EXT4_IOC32_GETVERSION:
  		cmd = EXT4_IOC_GETVERSION;
  		break;
  	case EXT4_IOC32_SETVERSION:
  		cmd = EXT4_IOC_SETVERSION;
  		break;
  	case EXT4_IOC32_GROUP_EXTEND:
  		cmd = EXT4_IOC_GROUP_EXTEND;
  		break;
  	case EXT4_IOC32_GETVERSION_OLD:
  		cmd = EXT4_IOC_GETVERSION_OLD;
  		break;
  	case EXT4_IOC32_SETVERSION_OLD:
  		cmd = EXT4_IOC_SETVERSION_OLD;
  		break;
  	case EXT4_IOC32_GETRSVSZ:
  		cmd = EXT4_IOC_GETRSVSZ;
  		break;
  	case EXT4_IOC32_SETRSVSZ:
  		cmd = EXT4_IOC_SETRSVSZ;
  		break;
  	case EXT4_IOC32_GROUP_ADD: {
  		struct compat_ext4_new_group_input __user *uinput;
  		struct ext4_new_group_input input;
  		mm_segment_t old_fs;
  		int err;
  
  		uinput = compat_ptr(arg);
  		err = get_user(input.group, &uinput->group);
  		err |= get_user(input.block_bitmap, &uinput->block_bitmap);
  		err |= get_user(input.inode_bitmap, &uinput->inode_bitmap);
  		err |= get_user(input.inode_table, &uinput->inode_table);
  		err |= get_user(input.blocks_count, &uinput->blocks_count);
  		err |= get_user(input.reserved_blocks,
  				&uinput->reserved_blocks);
  		if (err)
  			return -EFAULT;
  		old_fs = get_fs();
  		set_fs(KERNEL_DS);
  		err = ext4_ioctl(file, EXT4_IOC_GROUP_ADD,
  				 (unsigned long) &input);
  		set_fs(old_fs);
  		return err;
  	}
  	case EXT4_IOC_MOVE_EXT:
  	case FITRIM:
  	case EXT4_IOC_RESIZE_FS:
  	case EXT4_IOC_PRECACHE_EXTENTS:
  		break;
  	default:
  		return -ENOIOCTLCMD;
  	}
  	return ext4_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
  }
  #endif
  