alistair23-linux/fs/ext4/ioctl.c

/*
 * 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);

	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_metadata_csum(inode->i_sb)) {
			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:
	{
		int err;
		if (!(filp->f_mode & FMODE_WRITE))
			return -EBADF;
		err = mnt_want_write_file(filp);
		if (err)
			return err;
		err = swap_inode_boot_loader(sb, inode);
		mnt_drop_write_file(filp);
		return err;
	}

	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