// SPDX-License-Identifier: GPL-2.0+

  /*
   * ioctl.c - NILFS ioctl operations.
   *
   * Copyright (C) 2007, 2008 Nippon Telegraph and Telephone Corporation.
   *

   * Written by Koji Sato.

   */
  
  #include <linux/fs.h>
  #include <linux/wait.h>

  #include <linux/slab.h>

  #include <linux/capability.h>	/* capable() */
  #include <linux/uaccess.h>	/* copy_from_user(), copy_to_user() */

  #include <linux/vmalloc.h>

  #include <linux/compat.h>	/* compat_ptr() */

  #include <linux/mount.h>	/* mnt_want_write_file(), mnt_drop_write_file() */

  #include <linux/buffer_head.h>

  #include "nilfs.h"
  #include "segment.h"
  #include "bmap.h"
  #include "cpfile.h"
  #include "sufile.h"
  #include "dat.h"

  /**
   * nilfs_ioctl_wrap_copy - wrapping function of get/set metadata info
   * @nilfs: nilfs object
   * @argv: vector of arguments from userspace
   * @dir: set of direction flags
   * @dofunc: concrete function of get/set metadata info
   *
   * Description: nilfs_ioctl_wrap_copy() gets/sets metadata info by means of
   * calling dofunc() function on the basis of @argv argument.
   *
   * Return Value: On success, 0 is returned and requested metadata info
   * is copied into userspace. On error, one of the following
   * negative error codes is returned.
   *
   * %-EINVAL - Invalid arguments from userspace.
   *
   * %-ENOMEM - Insufficient amount of memory available.
   *
   * %-EFAULT - Failure during execution of requested operation.
   */

  static int nilfs_ioctl_wrap_copy(struct the_nilfs *nilfs,
  				 struct nilfs_argv *argv, int dir,
  				 ssize_t (*dofunc)(struct the_nilfs *,

  						   __u64 *, int,

  						   void *, size_t, size_t))
  {
  	void *buf;

  	void __user *base = (void __user *)(unsigned long)argv->v_base;

  	size_t maxmembs, total, n;

  	ssize_t nr;
  	int ret, i;

  	__u64 pos, ppos;

  
  	if (argv->v_nmembs == 0)
  		return 0;

  	if (argv->v_size > PAGE_SIZE)
  		return -EINVAL;

  	/*
  	 * Reject pairs of a start item position (argv->v_index) and a
  	 * total count (argv->v_nmembs) which leads position 'pos' to
  	 * overflow by the increment at the end of the loop.
  	 */
  	if (argv->v_index > ~(__u64)0 - argv->v_nmembs)
  		return -EINVAL;

  	buf = (void *)__get_free_pages(GFP_NOFS, 0);
  	if (unlikely(!buf))

  		return -ENOMEM;

  	maxmembs = PAGE_SIZE / argv->v_size;

  
  	ret = 0;
  	total = 0;

  	pos = argv->v_index;

  	for (i = 0; i < argv->v_nmembs; i += n) {
  		n = (argv->v_nmembs - i < maxmembs) ?
  			argv->v_nmembs - i : maxmembs;
  		if ((dir & _IOC_WRITE) &&

  		    copy_from_user(buf, base + argv->v_size * i,
  				   argv->v_size * n)) {

  			ret = -EFAULT;
  			break;
  		}

  		ppos = pos;

  		nr = dofunc(nilfs, &pos, argv->v_flags, buf, argv->v_size,

  			       n);

  		if (nr < 0) {
  			ret = nr;
  			break;
  		}
  		if ((dir & _IOC_READ) &&

  		    copy_to_user(base + argv->v_size * i, buf,
  				 argv->v_size * nr)) {

  			ret = -EFAULT;
  			break;
  		}
  		total += nr;

  		if ((size_t)nr < n)
  			break;
  		if (pos == ppos)
  			pos += n;

  	}
  	argv->v_nmembs = total;

  	free_pages((unsigned long)buf, 0);

  	return ret;
  }

  /**
   * nilfs_ioctl_getflags - ioctl to support lsattr
   */

  static int nilfs_ioctl_getflags(struct inode *inode, void __user *argp)
  {
  	unsigned int flags = NILFS_I(inode)->i_flags & FS_FL_USER_VISIBLE;
  
  	return put_user(flags, (int __user *)argp);
  }

  /**
   * nilfs_ioctl_setflags - ioctl to support chattr
   */

  static int nilfs_ioctl_setflags(struct inode *inode, struct file *filp,
  				void __user *argp)
  {
  	struct nilfs_transaction_info ti;
  	unsigned int flags, oldflags;
  	int ret;

  	if (!inode_owner_or_capable(inode))

  		return -EACCES;
  
  	if (get_user(flags, (int __user *)argp))
  		return -EFAULT;

  	ret = mnt_want_write_file(filp);

  	if (ret)
  		return ret;
  
  	flags = nilfs_mask_flags(inode->i_mode, flags);

  	inode_lock(inode);

  
  	oldflags = NILFS_I(inode)->i_flags;

  	ret = vfs_ioc_setflags_prepare(inode, oldflags, flags);
  	if (ret)

  		goto out;
  
  	ret = nilfs_transaction_begin(inode->i_sb, &ti, 0);
  	if (ret)
  		goto out;
  
  	NILFS_I(inode)->i_flags = (oldflags & ~FS_FL_USER_MODIFIABLE) |
  		(flags & FS_FL_USER_MODIFIABLE);
  
  	nilfs_set_inode_flags(inode);

  	inode->i_ctime = current_time(inode);

  	if (IS_SYNC(inode))
  		nilfs_set_transaction_flag(NILFS_TI_SYNC);
  
  	nilfs_mark_inode_dirty(inode);
  	ret = nilfs_transaction_commit(inode->i_sb);
  out:

  	inode_unlock(inode);

  	mnt_drop_write_file(filp);

  	return ret;
  }

  /**
   * nilfs_ioctl_getversion - get info about a file's version (generation number)
   */

  static int nilfs_ioctl_getversion(struct inode *inode, void __user *argp)
  {
  	return put_user(inode->i_generation, (int __user *)argp);
  }

  /**
   * nilfs_ioctl_change_cpmode - change checkpoint mode (checkpoint/snapshot)
   * @inode: inode object
   * @filp: file object
   * @cmd: ioctl's request code
   * @argp: pointer on argument from userspace
   *
   * Description: nilfs_ioctl_change_cpmode() function changes mode of
   * given checkpoint between checkpoint and snapshot state. This ioctl
   * is used in chcp and mkcp utilities.
   *
   * Return Value: On success, 0 is returned and mode of a checkpoint is
   * changed. On error, one of the following negative error codes
   * is returned.
   *
   * %-EPERM - Operation not permitted.
   *
   * %-EFAULT - Failure during checkpoint mode changing.
   */

  static int nilfs_ioctl_change_cpmode(struct inode *inode, struct file *filp,
  				     unsigned int cmd, void __user *argp)
  {

  	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;

  	struct nilfs_transaction_info ti;
  	struct nilfs_cpmode cpmode;
  	int ret;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;

  	ret = mnt_want_write_file(filp);

  	if (ret)
  		return ret;
  
  	ret = -EFAULT;

  	if (copy_from_user(&cpmode, argp, sizeof(cpmode)))

  		goto out;

  	mutex_lock(&nilfs->ns_snapshot_mount_mutex);

  	nilfs_transaction_begin(inode->i_sb, &ti, 0);
  	ret = nilfs_cpfile_change_cpmode(

  		nilfs->ns_cpfile, cpmode.cm_cno, cpmode.cm_mode);

  	if (unlikely(ret < 0))

  		nilfs_transaction_abort(inode->i_sb);

  	else
  		nilfs_transaction_commit(inode->i_sb); /* never fails */

  	mutex_unlock(&nilfs->ns_snapshot_mount_mutex);

  out:

  	mnt_drop_write_file(filp);

  	return ret;
  }

  /**
   * nilfs_ioctl_delete_checkpoint - remove checkpoint
   * @inode: inode object
   * @filp: file object
   * @cmd: ioctl's request code
   * @argp: pointer on argument from userspace
   *
   * Description: nilfs_ioctl_delete_checkpoint() function removes
   * checkpoint from NILFS2 file system. This ioctl is used in rmcp
   * utility.
   *
   * Return Value: On success, 0 is returned and a checkpoint is
   * removed. On error, one of the following negative error codes
   * is returned.
   *
   * %-EPERM - Operation not permitted.
   *
   * %-EFAULT - Failure during checkpoint removing.
   */

  static int
  nilfs_ioctl_delete_checkpoint(struct inode *inode, struct file *filp,
  			      unsigned int cmd, void __user *argp)
  {

  	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;

  	struct nilfs_transaction_info ti;
  	__u64 cno;
  	int ret;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;

  	ret = mnt_want_write_file(filp);

  	if (ret)
  		return ret;
  
  	ret = -EFAULT;

  	if (copy_from_user(&cno, argp, sizeof(cno)))

  		goto out;

  
  	nilfs_transaction_begin(inode->i_sb, &ti, 0);

  	ret = nilfs_cpfile_delete_checkpoint(nilfs->ns_cpfile, cno);

  	if (unlikely(ret < 0))

  		nilfs_transaction_abort(inode->i_sb);

  	else
  		nilfs_transaction_commit(inode->i_sb); /* never fails */
  out:

  	mnt_drop_write_file(filp);

  	return ret;
  }

  /**
   * nilfs_ioctl_do_get_cpinfo - callback method getting info about checkpoints
   * @nilfs: nilfs object
   * @posp: pointer on array of checkpoint's numbers
   * @flags: checkpoint mode (checkpoint or snapshot)
   * @buf: buffer for storing checkponts' info
   * @size: size in bytes of one checkpoint info item in array
   * @nmembs: number of checkpoints in array (numbers and infos)
   *
   * Description: nilfs_ioctl_do_get_cpinfo() function returns info about
   * requested checkpoints. The NILFS_IOCTL_GET_CPINFO ioctl is used in
   * lscp utility and by nilfs_cleanerd daemon.
   *
   * Return value: count of nilfs_cpinfo structures in output buffer.
   */

  static ssize_t

  nilfs_ioctl_do_get_cpinfo(struct the_nilfs *nilfs, __u64 *posp, int flags,

  			  void *buf, size_t size, size_t nmembs)
  {

  	int ret;

  	down_read(&nilfs->ns_segctor_sem);

  	ret = nilfs_cpfile_get_cpinfo(nilfs->ns_cpfile, posp, flags, buf,

  				      size, nmembs);

  	up_read(&nilfs->ns_segctor_sem);

  	return ret;
  }

  /**
   * nilfs_ioctl_get_cpstat - get checkpoints statistics
   * @inode: inode object
   * @filp: file object
   * @cmd: ioctl's request code
   * @argp: pointer on argument from userspace
   *
   * Description: nilfs_ioctl_get_cpstat() returns information about checkpoints.
   * The NILFS_IOCTL_GET_CPSTAT ioctl is used by lscp, rmcp utilities
   * and by nilfs_cleanerd daemon.
   *
   * Return Value: On success, 0 is returned, and checkpoints information is
   * copied into userspace pointer @argp. On error, one of the following
   * negative error codes is returned.
   *
   * %-EIO - I/O error.
   *
   * %-ENOMEM - Insufficient amount of memory available.
   *
   * %-EFAULT - Failure during getting checkpoints statistics.
   */

  static int nilfs_ioctl_get_cpstat(struct inode *inode, struct file *filp,
  				  unsigned int cmd, void __user *argp)
  {

  	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;

  	struct nilfs_cpstat cpstat;

  	int ret;

  	down_read(&nilfs->ns_segctor_sem);
  	ret = nilfs_cpfile_get_stat(nilfs->ns_cpfile, &cpstat);
  	up_read(&nilfs->ns_segctor_sem);

  	if (ret < 0)
  		return ret;
  
  	if (copy_to_user(argp, &cpstat, sizeof(cpstat)))
  		ret = -EFAULT;
  	return ret;
  }

  /**
   * nilfs_ioctl_do_get_suinfo - callback method getting segment usage info
   * @nilfs: nilfs object
   * @posp: pointer on array of segment numbers
   * @flags: *not used*
   * @buf: buffer for storing suinfo array
   * @size: size in bytes of one suinfo item in array
   * @nmembs: count of segment numbers and suinfos in array
   *
   * Description: nilfs_ioctl_do_get_suinfo() function returns segment usage
   * info about requested segments. The NILFS_IOCTL_GET_SUINFO ioctl is used
   * in lssu, nilfs_resize utilities and by nilfs_cleanerd daemon.
   *
   * Return value: count of nilfs_suinfo structures in output buffer.
   */

  static ssize_t

  nilfs_ioctl_do_get_suinfo(struct the_nilfs *nilfs, __u64 *posp, int flags,

  			  void *buf, size_t size, size_t nmembs)
  {

  	int ret;

  	down_read(&nilfs->ns_segctor_sem);

  	ret = nilfs_sufile_get_suinfo(nilfs->ns_sufile, *posp, buf, size,
  				      nmembs);

  	up_read(&nilfs->ns_segctor_sem);

  	return ret;
  }

  /**
   * nilfs_ioctl_get_sustat - get segment usage statistics
   * @inode: inode object
   * @filp: file object
   * @cmd: ioctl's request code
   * @argp: pointer on argument from userspace
   *
   * Description: nilfs_ioctl_get_sustat() returns segment usage statistics.
   * The NILFS_IOCTL_GET_SUSTAT ioctl is used in lssu, nilfs_resize utilities
   * and by nilfs_cleanerd daemon.
   *
   * Return Value: On success, 0 is returned, and segment usage information is
   * copied into userspace pointer @argp. On error, one of the following
   * negative error codes is returned.
   *
   * %-EIO - I/O error.
   *
   * %-ENOMEM - Insufficient amount of memory available.
   *
   * %-EFAULT - Failure during getting segment usage statistics.
   */

  static int nilfs_ioctl_get_sustat(struct inode *inode, struct file *filp,
  				  unsigned int cmd, void __user *argp)
  {

  	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;

  	struct nilfs_sustat sustat;

  	int ret;

  	down_read(&nilfs->ns_segctor_sem);
  	ret = nilfs_sufile_get_stat(nilfs->ns_sufile, &sustat);
  	up_read(&nilfs->ns_segctor_sem);

  	if (ret < 0)
  		return ret;
  
  	if (copy_to_user(argp, &sustat, sizeof(sustat)))
  		ret = -EFAULT;
  	return ret;
  }

  /**
   * nilfs_ioctl_do_get_vinfo - callback method getting virtual blocks info
   * @nilfs: nilfs object
   * @posp: *not used*
   * @flags: *not used*
   * @buf: buffer for storing array of nilfs_vinfo structures
   * @size: size in bytes of one vinfo item in array
   * @nmembs: count of vinfos in array
   *
   * Description: nilfs_ioctl_do_get_vinfo() function returns information
   * on virtual block addresses. The NILFS_IOCTL_GET_VINFO ioctl is used
   * by nilfs_cleanerd daemon.
   *
   * Return value: count of nilfs_vinfo structures in output buffer.
   */

  static ssize_t

  nilfs_ioctl_do_get_vinfo(struct the_nilfs *nilfs, __u64 *posp, int flags,

  			 void *buf, size_t size, size_t nmembs)
  {

  	int ret;

  	down_read(&nilfs->ns_segctor_sem);

  	ret = nilfs_dat_get_vinfo(nilfs->ns_dat, buf, size, nmembs);

  	up_read(&nilfs->ns_segctor_sem);

  	return ret;
  }

  /**
   * nilfs_ioctl_do_get_bdescs - callback method getting disk block descriptors
   * @nilfs: nilfs object
   * @posp: *not used*
   * @flags: *not used*
   * @buf: buffer for storing array of nilfs_bdesc structures
   * @size: size in bytes of one bdesc item in array
   * @nmembs: count of bdescs in array
   *
   * Description: nilfs_ioctl_do_get_bdescs() function returns information
   * about descriptors of disk block numbers. The NILFS_IOCTL_GET_BDESCS ioctl
   * is used by nilfs_cleanerd daemon.
   *
   * Return value: count of nilfs_bdescs structures in output buffer.
   */

  static ssize_t

  nilfs_ioctl_do_get_bdescs(struct the_nilfs *nilfs, __u64 *posp, int flags,

  			  void *buf, size_t size, size_t nmembs)
  {

  	struct nilfs_bmap *bmap = NILFS_I(nilfs->ns_dat)->i_bmap;

  	struct nilfs_bdesc *bdescs = buf;
  	int ret, i;

  	down_read(&nilfs->ns_segctor_sem);

  	for (i = 0; i < nmembs; i++) {
  		ret = nilfs_bmap_lookup_at_level(bmap,
  						 bdescs[i].bd_offset,
  						 bdescs[i].bd_level + 1,
  						 &bdescs[i].bd_blocknr);
  		if (ret < 0) {

  			if (ret != -ENOENT) {
  				up_read(&nilfs->ns_segctor_sem);

  				return ret;

  			}

  			bdescs[i].bd_blocknr = 0;
  		}
  	}

  	up_read(&nilfs->ns_segctor_sem);

  	return nmembs;
  }

  /**
   * nilfs_ioctl_get_bdescs - get disk block descriptors
   * @inode: inode object
   * @filp: file object
   * @cmd: ioctl's request code
   * @argp: pointer on argument from userspace
   *
   * Description: nilfs_ioctl_do_get_bdescs() function returns information
   * about descriptors of disk block numbers. The NILFS_IOCTL_GET_BDESCS ioctl
   * is used by nilfs_cleanerd daemon.
   *
   * Return Value: On success, 0 is returned, and disk block descriptors are
   * copied into userspace pointer @argp. On error, one of the following
   * negative error codes is returned.
   *
   * %-EINVAL - Invalid arguments from userspace.
   *
   * %-EIO - I/O error.
   *
   * %-ENOMEM - Insufficient amount of memory available.
   *
   * %-EFAULT - Failure during getting disk block descriptors.
   */

  static int nilfs_ioctl_get_bdescs(struct inode *inode, struct file *filp,
  				  unsigned int cmd, void __user *argp)
  {

  	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;

  	struct nilfs_argv argv;

  	int ret;
  
  	if (copy_from_user(&argv, argp, sizeof(argv)))
  		return -EFAULT;

  	if (argv.v_size != sizeof(struct nilfs_bdesc))
  		return -EINVAL;

  	ret = nilfs_ioctl_wrap_copy(nilfs, &argv, _IOC_DIR(cmd),
  				    nilfs_ioctl_do_get_bdescs);

  	if (ret < 0)
  		return ret;

  
  	if (copy_to_user(argp, &argv, sizeof(argv)))
  		ret = -EFAULT;
  	return ret;
  }

  /**
   * nilfs_ioctl_move_inode_block - prepare data/node block for moving by GC
   * @inode: inode object
   * @vdesc: descriptor of virtual block number
   * @buffers: list of moving buffers
   *
   * Description: nilfs_ioctl_move_inode_block() function registers data/node
   * buffer in the GC pagecache and submit read request.
   *
   * Return Value: On success, 0 is returned. On error, one of the following
   * negative error codes is returned.
   *
   * %-EIO - I/O error.
   *
   * %-ENOMEM - Insufficient amount of memory available.
   *
   * %-ENOENT - Requested block doesn't exist.
   *
   * %-EEXIST - Blocks conflict is detected.
   */

  static int nilfs_ioctl_move_inode_block(struct inode *inode,
  					struct nilfs_vdesc *vdesc,
  					struct list_head *buffers)
  {
  	struct buffer_head *bh;
  	int ret;
  
  	if (vdesc->vd_flags == 0)
  		ret = nilfs_gccache_submit_read_data(
  			inode, vdesc->vd_offset, vdesc->vd_blocknr,
  			vdesc->vd_vblocknr, &bh);
  	else
  		ret = nilfs_gccache_submit_read_node(
  			inode, vdesc->vd_blocknr, vdesc->vd_vblocknr, &bh);
  
  	if (unlikely(ret < 0)) {
  		if (ret == -ENOENT)

  			nilfs_crit(inode->i_sb,
  				   "%s: invalid virtual block address (%s): ino=%llu, cno=%llu, offset=%llu, blocknr=%llu, vblocknr=%llu",
  				   __func__, vdesc->vd_flags ? "node" : "data",
  				   (unsigned long long)vdesc->vd_ino,
  				   (unsigned long long)vdesc->vd_cno,
  				   (unsigned long long)vdesc->vd_offset,
  				   (unsigned long long)vdesc->vd_blocknr,
  				   (unsigned long long)vdesc->vd_vblocknr);

  		return ret;
  	}

  	if (unlikely(!list_empty(&bh->b_assoc_buffers))) {

  		nilfs_crit(inode->i_sb,
  			   "%s: conflicting %s buffer: ino=%llu, cno=%llu, offset=%llu, blocknr=%llu, vblocknr=%llu",
  			   __func__, vdesc->vd_flags ? "node" : "data",
  			   (unsigned long long)vdesc->vd_ino,
  			   (unsigned long long)vdesc->vd_cno,
  			   (unsigned long long)vdesc->vd_offset,
  			   (unsigned long long)vdesc->vd_blocknr,
  			   (unsigned long long)vdesc->vd_vblocknr);

  		brelse(bh);
  		return -EEXIST;
  	}

  	list_add_tail(&bh->b_assoc_buffers, buffers);
  	return 0;
  }

  /**
   * nilfs_ioctl_move_blocks - move valid inode's blocks during garbage collection
   * @sb: superblock object
   * @argv: vector of arguments from userspace
   * @buf: array of nilfs_vdesc structures
   *
   * Description: nilfs_ioctl_move_blocks() function reads valid data/node
   * blocks that garbage collector specified with the array of nilfs_vdesc
   * structures and stores them into page caches of GC inodes.
   *
   * Return Value: Number of processed nilfs_vdesc structures or
   * error code, otherwise.
   */

  static int nilfs_ioctl_move_blocks(struct super_block *sb,

  				   struct nilfs_argv *argv, void *buf)

  {

  	size_t nmembs = argv->v_nmembs;

  	struct the_nilfs *nilfs = sb->s_fs_info;

  	struct inode *inode;
  	struct nilfs_vdesc *vdesc;
  	struct buffer_head *bh, *n;
  	LIST_HEAD(buffers);
  	ino_t ino;
  	__u64 cno;
  	int i, ret;
  
  	for (i = 0, vdesc = buf; i < nmembs; ) {
  		ino = vdesc->vd_ino;
  		cno = vdesc->vd_cno;

  		inode = nilfs_iget_for_gc(sb, ino, cno);

  		if (IS_ERR(inode)) {
  			ret = PTR_ERR(inode);

  			goto failed;
  		}

  		if (list_empty(&NILFS_I(inode)->i_dirty)) {
  			/*
  			 * Add the inode to GC inode list. Garbage Collection
  			 * is serialized and no two processes manipulate the
  			 * list simultaneously.
  			 */
  			igrab(inode);
  			list_add(&NILFS_I(inode)->i_dirty,
  				 &nilfs->ns_gc_inodes);
  		}

  		do {
  			ret = nilfs_ioctl_move_inode_block(inode, vdesc,
  							   &buffers);

  			if (unlikely(ret < 0)) {
  				iput(inode);

  				goto failed;

  			}

  			vdesc++;
  		} while (++i < nmembs &&
  			 vdesc->vd_ino == ino && vdesc->vd_cno == cno);

  
  		iput(inode); /* The inode still remains in GC inode list */

  	}
  
  	list_for_each_entry_safe(bh, n, &buffers, b_assoc_buffers) {
  		ret = nilfs_gccache_wait_and_mark_dirty(bh);
  		if (unlikely(ret < 0)) {

  			WARN_ON(ret == -EEXIST);

  			goto failed;
  		}
  		list_del_init(&bh->b_assoc_buffers);

  		brelse(bh);
  	}
  	return nmembs;
  
   failed:
  	list_for_each_entry_safe(bh, n, &buffers, b_assoc_buffers) {
  		list_del_init(&bh->b_assoc_buffers);

  		brelse(bh);
  	}
  	return ret;
  }

  /**
   * nilfs_ioctl_delete_checkpoints - delete checkpoints
   * @nilfs: nilfs object
   * @argv: vector of arguments from userspace
   * @buf: array of periods of checkpoints numbers
   *
   * Description: nilfs_ioctl_delete_checkpoints() function deletes checkpoints
   * in the period from p_start to p_end, excluding p_end itself. The checkpoints
   * which have been already deleted are ignored.
   *
   * Return Value: Number of processed nilfs_period structures or
   * error code, otherwise.
   *
   * %-EIO - I/O error.
   *
   * %-ENOMEM - Insufficient amount of memory available.
   *
   * %-EINVAL - invalid checkpoints.
   */

  static int nilfs_ioctl_delete_checkpoints(struct the_nilfs *nilfs,
  					  struct nilfs_argv *argv, void *buf)

  {

  	size_t nmembs = argv->v_nmembs;

  	struct inode *cpfile = nilfs->ns_cpfile;
  	struct nilfs_period *periods = buf;
  	int ret, i;
  
  	for (i = 0; i < nmembs; i++) {
  		ret = nilfs_cpfile_delete_checkpoints(
  			cpfile, periods[i].p_start, periods[i].p_end);
  		if (ret < 0)
  			return ret;
  	}
  	return nmembs;
  }

  /**
   * nilfs_ioctl_free_vblocknrs - free virtual block numbers
   * @nilfs: nilfs object
   * @argv: vector of arguments from userspace
   * @buf: array of virtual block numbers
   *
   * Description: nilfs_ioctl_free_vblocknrs() function frees
   * the virtual block numbers specified by @buf and @argv->v_nmembs.
   *
   * Return Value: Number of processed virtual block numbers or
   * error code, otherwise.
   *
   * %-EIO - I/O error.
   *
   * %-ENOMEM - Insufficient amount of memory available.
   *
   * %-ENOENT - The virtual block number have not been allocated.
   */

  static int nilfs_ioctl_free_vblocknrs(struct the_nilfs *nilfs,
  				      struct nilfs_argv *argv, void *buf)

  {

  	size_t nmembs = argv->v_nmembs;
  	int ret;

  	ret = nilfs_dat_freev(nilfs->ns_dat, buf, nmembs);

  
  	return (ret < 0) ? ret : nmembs;
  }

  /**
   * nilfs_ioctl_mark_blocks_dirty - mark blocks dirty
   * @nilfs: nilfs object
   * @argv: vector of arguments from userspace
   * @buf: array of block descriptors
   *
   * Description: nilfs_ioctl_mark_blocks_dirty() function marks
   * metadata file or data blocks as dirty.
   *
   * Return Value: Number of processed block descriptors or
   * error code, otherwise.
   *
   * %-ENOMEM - Insufficient memory available.
   *
   * %-EIO - I/O error
   *
   * %-ENOENT - the specified block does not exist (hole block)
   */

  static int nilfs_ioctl_mark_blocks_dirty(struct the_nilfs *nilfs,
  					 struct nilfs_argv *argv, void *buf)

  {

  	size_t nmembs = argv->v_nmembs;

  	struct nilfs_bmap *bmap = NILFS_I(nilfs->ns_dat)->i_bmap;

  	struct nilfs_bdesc *bdescs = buf;

  	struct buffer_head *bh;

  	int ret, i;
  
  	for (i = 0; i < nmembs; i++) {
  		/* XXX: use macro or inline func to check liveness */
  		ret = nilfs_bmap_lookup_at_level(bmap,
  						 bdescs[i].bd_offset,
  						 bdescs[i].bd_level + 1,
  						 &bdescs[i].bd_blocknr);
  		if (ret < 0) {
  			if (ret != -ENOENT)
  				return ret;
  			bdescs[i].bd_blocknr = 0;
  		}
  		if (bdescs[i].bd_blocknr != bdescs[i].bd_oblocknr)
  			/* skip dead block */
  			continue;
  		if (bdescs[i].bd_level == 0) {

  			ret = nilfs_mdt_get_block(nilfs->ns_dat,
  						  bdescs[i].bd_offset,
  						  false, NULL, &bh);
  			if (unlikely(ret)) {

  				WARN_ON(ret == -ENOENT);

  				return ret;
  			}

  			mark_buffer_dirty(bh);
  			nilfs_mdt_mark_dirty(nilfs->ns_dat);
  			put_bh(bh);

  		} else {
  			ret = nilfs_bmap_mark(bmap, bdescs[i].bd_offset,
  					      bdescs[i].bd_level);
  			if (ret < 0) {

  				WARN_ON(ret == -ENOENT);

  				return ret;
  			}
  		}
  	}
  	return nmembs;
  }

  int nilfs_ioctl_prepare_clean_segments(struct the_nilfs *nilfs,

  				       struct nilfs_argv *argv, void **kbufs)

  {

  	const char *msg;

  	int ret;

  	ret = nilfs_ioctl_delete_checkpoints(nilfs, &argv[1], kbufs[1]);

  	if (ret < 0) {
  		/*
  		 * can safely abort because checkpoints can be removed
  		 * independently.
  		 */
  		msg = "cannot delete checkpoints";
  		goto failed;
  	}

  	ret = nilfs_ioctl_free_vblocknrs(nilfs, &argv[2], kbufs[2]);

  	if (ret < 0) {
  		/*
  		 * can safely abort because DAT file is updated atomically
  		 * using a copy-on-write technique.
  		 */
  		msg = "cannot delete virtual blocks from DAT file";
  		goto failed;
  	}

  	ret = nilfs_ioctl_mark_blocks_dirty(nilfs, &argv[3], kbufs[3]);

  	if (ret < 0) {
  		/*
  		 * can safely abort because the operation is nondestructive.
  		 */
  		msg = "cannot mark copying blocks dirty";
  		goto failed;
  	}

  	return 0;

   failed:

  	nilfs_err(nilfs->ns_sb, "error %d preparing GC: %s", ret, msg);

  	return ret;
  }

  /**
   * nilfs_ioctl_clean_segments - clean segments
   * @inode: inode object
   * @filp: file object
   * @cmd: ioctl's request code
   * @argp: pointer on argument from userspace
   *
   * Description: nilfs_ioctl_clean_segments() function makes garbage
   * collection operation in the environment of requested parameters
   * from userspace. The NILFS_IOCTL_CLEAN_SEGMENTS ioctl is used by
   * nilfs_cleanerd daemon.
   *
   * Return Value: On success, 0 is returned or error code, otherwise.
   */

  static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp,
  				      unsigned int cmd, void __user *argp)
  {

  	struct nilfs_argv argv[5];

  	static const size_t argsz[5] = {

  		sizeof(struct nilfs_vdesc),
  		sizeof(struct nilfs_period),
  		sizeof(__u64),
  		sizeof(struct nilfs_bdesc),
  		sizeof(__u64),
  	};
  	void __user *base;
  	void *kbufs[5];
  	struct the_nilfs *nilfs;
  	size_t len, nsegs;
  	int n, ret;

  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;

  	ret = mnt_want_write_file(filp);

  	if (ret)
  		return ret;
  
  	ret = -EFAULT;

  	if (copy_from_user(argv, argp, sizeof(argv)))

  		goto out;

  	ret = -EINVAL;

  	nsegs = argv[4].v_nmembs;
  	if (argv[4].v_size != argsz[4])

  		goto out;

  	if (nsegs > UINT_MAX / sizeof(__u64))
  		goto out;

  	/*
  	 * argv[4] points to segment numbers this ioctl cleans.  We
  	 * use kmalloc() for its buffer because memory used for the
  	 * segment numbers is enough small.
  	 */
  	kbufs[4] = memdup_user((void __user *)(unsigned long)argv[4].v_base,
  			       nsegs * sizeof(__u64));

  	if (IS_ERR(kbufs[4])) {
  		ret = PTR_ERR(kbufs[4]);
  		goto out;
  	}

  	nilfs = inode->i_sb->s_fs_info;

  
  	for (n = 0; n < 4; n++) {
  		ret = -EINVAL;
  		if (argv[n].v_size != argsz[n])
  			goto out_free;
  
  		if (argv[n].v_nmembs > nsegs * nilfs->ns_blocks_per_segment)
  			goto out_free;

  		if (argv[n].v_nmembs >= UINT_MAX / argv[n].v_size)
  			goto out_free;

  		len = argv[n].v_size * argv[n].v_nmembs;
  		base = (void __user *)(unsigned long)argv[n].v_base;
  		if (len == 0) {
  			kbufs[n] = NULL;
  			continue;
  		}
  
  		kbufs[n] = vmalloc(len);
  		if (!kbufs[n]) {
  			ret = -ENOMEM;
  			goto out_free;
  		}
  		if (copy_from_user(kbufs[n], base, len)) {
  			ret = -EFAULT;
  			vfree(kbufs[n]);
  			goto out_free;
  		}
  	}

  	/*

  	 * nilfs_ioctl_move_blocks() will call nilfs_iget_for_gc(),

  	 * which will operates an inode list without blocking.
  	 * To protect the list from concurrent operations,
  	 * nilfs_ioctl_move_blocks should be atomic operation.
  	 */
  	if (test_and_set_bit(THE_NILFS_GC_RUNNING, &nilfs->ns_flags)) {
  		ret = -EBUSY;
  		goto out_free;
  	}

  	ret = nilfs_ioctl_move_blocks(inode->i_sb, &argv[0], kbufs[0]);

  	if (ret < 0) {

  		nilfs_err(inode->i_sb,

  			  "error %d preparing GC: cannot read source blocks",
  			  ret);
  	} else {

  		if (nilfs_sb_need_update(nilfs))
  			set_nilfs_discontinued(nilfs);

  		ret = nilfs_clean_segments(inode->i_sb, argv, kbufs);

  	}

  	nilfs_remove_all_gcinodes(nilfs);

  	clear_nilfs_gc_running(nilfs);

  out_free:

  	while (--n >= 0)

  		vfree(kbufs[n]);
  	kfree(kbufs[4]);

  out:

  	mnt_drop_write_file(filp);

  	return ret;

  }

  /**
   * nilfs_ioctl_sync - make a checkpoint
   * @inode: inode object
   * @filp: file object
   * @cmd: ioctl's request code
   * @argp: pointer on argument from userspace
   *
   * Description: nilfs_ioctl_sync() function constructs a logical segment
   * for checkpointing.  This function guarantees that all modified data
   * and metadata are written out to the device when it successfully
   * returned.
   *
   * Return Value: On success, 0 is retured. On errors, one of the following
   * negative error code is returned.
   *
   * %-EROFS - Read only filesystem.
   *
   * %-EIO - I/O error
   *
   * %-ENOSPC - No space left on device (only in a panic state).
   *
   * %-ERESTARTSYS - Interrupted.
   *
   * %-ENOMEM - Insufficient memory available.
   *
   * %-EFAULT - Failure during execution of requested operation.
   */

  static int nilfs_ioctl_sync(struct inode *inode, struct file *filp,
  			    unsigned int cmd, void __user *argp)
  {
  	__u64 cno;
  	int ret;

  	struct the_nilfs *nilfs;

  
  	ret = nilfs_construct_segment(inode->i_sb);
  	if (ret < 0)
  		return ret;

  	nilfs = inode->i_sb->s_fs_info;

  	ret = nilfs_flush_device(nilfs);
  	if (ret < 0)
  		return ret;

  	if (argp != NULL) {

  		down_read(&nilfs->ns_segctor_sem);
  		cno = nilfs->ns_cno - 1;
  		up_read(&nilfs->ns_segctor_sem);

  		if (copy_to_user(argp, &cno, sizeof(cno)))
  			return -EFAULT;
  	}
  	return 0;
  }

  /**
   * nilfs_ioctl_resize - resize NILFS2 volume
   * @inode: inode object
   * @filp: file object
   * @argp: pointer on argument from userspace
   *
   * Return Value: On success, 0 is returned or error code, otherwise.
   */

  static int nilfs_ioctl_resize(struct inode *inode, struct file *filp,
  			      void __user *argp)
  {
  	__u64 newsize;
  	int ret = -EPERM;
  
  	if (!capable(CAP_SYS_ADMIN))
  		goto out;

  	ret = mnt_want_write_file(filp);

  	if (ret)
  		goto out;
  
  	ret = -EFAULT;
  	if (copy_from_user(&newsize, argp, sizeof(newsize)))
  		goto out_drop_write;
  
  	ret = nilfs_resize_fs(inode->i_sb, newsize);
  
  out_drop_write:

  	mnt_drop_write_file(filp);

  out:
  	return ret;
  }

  /**

   * nilfs_ioctl_trim_fs() - trim ioctl handle function
   * @inode: inode object
   * @argp: pointer on argument from userspace
   *
   * Decription: nilfs_ioctl_trim_fs is the FITRIM ioctl handle function. It
   * checks the arguments from userspace and calls nilfs_sufile_trim_fs, which
   * performs the actual trim operation.
   *
   * Return Value: On success, 0 is returned or negative error code, otherwise.
   */
  static int nilfs_ioctl_trim_fs(struct inode *inode, void __user *argp)
  {
  	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
  	struct request_queue *q = bdev_get_queue(nilfs->ns_bdev);
  	struct fstrim_range range;
  	int ret;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;
  
  	if (!blk_queue_discard(q))
  		return -EOPNOTSUPP;
  
  	if (copy_from_user(&range, argp, sizeof(range)))
  		return -EFAULT;
  
  	range.minlen = max_t(u64, range.minlen, q->limits.discard_granularity);
  
  	down_read(&nilfs->ns_segctor_sem);
  	ret = nilfs_sufile_trim_fs(nilfs->ns_sufile, &range);
  	up_read(&nilfs->ns_segctor_sem);
  
  	if (ret < 0)
  		return ret;
  
  	if (copy_to_user(argp, &range, sizeof(range)))
  		return -EFAULT;
  
  	return 0;
  }
  
  /**

   * nilfs_ioctl_set_alloc_range - limit range of segments to be allocated
   * @inode: inode object
   * @argp: pointer on argument from userspace
   *
   * Decription: nilfs_ioctl_set_alloc_range() function defines lower limit
   * of segments in bytes and upper limit of segments in bytes.
   * The NILFS_IOCTL_SET_ALLOC_RANGE is used by nilfs_resize utility.
   *
   * Return Value: On success, 0 is returned or error code, otherwise.
   */

  static int nilfs_ioctl_set_alloc_range(struct inode *inode, void __user *argp)
  {
  	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
  	__u64 range[2];
  	__u64 minseg, maxseg;
  	unsigned long segbytes;
  	int ret = -EPERM;
  
  	if (!capable(CAP_SYS_ADMIN))
  		goto out;
  
  	ret = -EFAULT;
  	if (copy_from_user(range, argp, sizeof(__u64[2])))
  		goto out;
  
  	ret = -ERANGE;
  	if (range[1] > i_size_read(inode->i_sb->s_bdev->bd_inode))
  		goto out;
  
  	segbytes = nilfs->ns_blocks_per_segment * nilfs->ns_blocksize;
  
  	minseg = range[0] + segbytes - 1;
  	do_div(minseg, segbytes);
  	maxseg = NILFS_SB2_OFFSET_BYTES(range[1]);
  	do_div(maxseg, segbytes);
  	maxseg--;
  
  	ret = nilfs_sufile_set_alloc_range(nilfs->ns_sufile, minseg, maxseg);
  out:
  	return ret;
  }

  /**
   * nilfs_ioctl_get_info - wrapping function of get metadata info
   * @inode: inode object
   * @filp: file object
   * @cmd: ioctl's request code
   * @argp: pointer on argument from userspace
   * @membsz: size of an item in bytes
   * @dofunc: concrete function of getting metadata info
   *
   * Description: nilfs_ioctl_get_info() gets metadata info by means of
   * calling dofunc() function.
   *
   * Return Value: On success, 0 is returned and requested metadata info
   * is copied into userspace. On error, one of the following
   * negative error codes is returned.
   *
   * %-EINVAL - Invalid arguments from userspace.
   *
   * %-ENOMEM - Insufficient amount of memory available.
   *
   * %-EFAULT - Failure during execution of requested operation.
   */

  static int nilfs_ioctl_get_info(struct inode *inode, struct file *filp,
  				unsigned int cmd, void __user *argp,

  				size_t membsz,

  				ssize_t (*dofunc)(struct the_nilfs *,
  						  __u64 *, int,
  						  void *, size_t, size_t))
  
  {

  	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;

  	struct nilfs_argv argv;
  	int ret;
  
  	if (copy_from_user(&argv, argp, sizeof(argv)))
  		return -EFAULT;

  	if (argv.v_size < membsz)

  		return -EINVAL;

  	ret = nilfs_ioctl_wrap_copy(nilfs, &argv, _IOC_DIR(cmd), dofunc);
  	if (ret < 0)
  		return ret;
  
  	if (copy_to_user(argp, &argv, sizeof(argv)))
  		ret = -EFAULT;
  	return ret;
  }

  /**
   * nilfs_ioctl_set_suinfo - set segment usage info
   * @inode: inode object
   * @filp: file object
   * @cmd: ioctl's request code
   * @argp: pointer on argument from userspace
   *
   * Description: Expects an array of nilfs_suinfo_update structures
   * encapsulated in nilfs_argv and updates the segment usage info
   * according to the flags in nilfs_suinfo_update.
   *
   * Return Value: On success, 0 is returned. On error, one of the
   * following negative error codes is returned.
   *
   * %-EPERM - Not enough permissions
   *
   * %-EFAULT - Error copying input data
   *
   * %-EIO - I/O error.
   *
   * %-ENOMEM - Insufficient amount of memory available.
   *
   * %-EINVAL - Invalid values in input (segment number, flags or nblocks)
   */
  static int nilfs_ioctl_set_suinfo(struct inode *inode, struct file *filp,
  				unsigned int cmd, void __user *argp)
  {
  	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
  	struct nilfs_transaction_info ti;
  	struct nilfs_argv argv;
  	size_t len;
  	void __user *base;
  	void *kbuf;
  	int ret;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;
  
  	ret = mnt_want_write_file(filp);
  	if (ret)
  		return ret;
  
  	ret = -EFAULT;
  	if (copy_from_user(&argv, argp, sizeof(argv)))
  		goto out;
  
  	ret = -EINVAL;
  	if (argv.v_size < sizeof(struct nilfs_suinfo_update))
  		goto out;
  
  	if (argv.v_nmembs > nilfs->ns_nsegments)
  		goto out;
  
  	if (argv.v_nmembs >= UINT_MAX / argv.v_size)
  		goto out;
  
  	len = argv.v_size * argv.v_nmembs;
  	if (!len) {
  		ret = 0;
  		goto out;
  	}
  
  	base = (void __user *)(unsigned long)argv.v_base;
  	kbuf = vmalloc(len);
  	if (!kbuf) {
  		ret = -ENOMEM;
  		goto out;
  	}
  
  	if (copy_from_user(kbuf, base, len)) {
  		ret = -EFAULT;
  		goto out_free;
  	}
  
  	nilfs_transaction_begin(inode->i_sb, &ti, 0);
  	ret = nilfs_sufile_set_suinfo(nilfs->ns_sufile, kbuf, argv.v_size,
  			argv.v_nmembs);
  	if (unlikely(ret < 0))
  		nilfs_transaction_abort(inode->i_sb);
  	else
  		nilfs_transaction_commit(inode->i_sb); /* never fails */
  
  out_free:
  	vfree(kbuf);
  out:
  	mnt_drop_write_file(filp);
  	return ret;
  }

  long nilfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)

  {

  	struct inode *inode = file_inode(filp);

  	void __user *argp = (void __user *)arg;

  
  	switch (cmd) {

  	case FS_IOC_GETFLAGS:
  		return nilfs_ioctl_getflags(inode, argp);
  	case FS_IOC_SETFLAGS:
  		return nilfs_ioctl_setflags(inode, filp, argp);
  	case FS_IOC_GETVERSION:
  		return nilfs_ioctl_getversion(inode, argp);

  	case NILFS_IOCTL_CHANGE_CPMODE:
  		return nilfs_ioctl_change_cpmode(inode, filp, cmd, argp);
  	case NILFS_IOCTL_DELETE_CHECKPOINT:
  		return nilfs_ioctl_delete_checkpoint(inode, filp, cmd, argp);
  	case NILFS_IOCTL_GET_CPINFO:

  		return nilfs_ioctl_get_info(inode, filp, cmd, argp,

  					    sizeof(struct nilfs_cpinfo),

  					    nilfs_ioctl_do_get_cpinfo);

  	case NILFS_IOCTL_GET_CPSTAT:
  		return nilfs_ioctl_get_cpstat(inode, filp, cmd, argp);
  	case NILFS_IOCTL_GET_SUINFO:

  		return nilfs_ioctl_get_info(inode, filp, cmd, argp,

  					    sizeof(struct nilfs_suinfo),

  					    nilfs_ioctl_do_get_suinfo);

  	case NILFS_IOCTL_SET_SUINFO:
  		return nilfs_ioctl_set_suinfo(inode, filp, cmd, argp);

  	case NILFS_IOCTL_GET_SUSTAT:
  		return nilfs_ioctl_get_sustat(inode, filp, cmd, argp);
  	case NILFS_IOCTL_GET_VINFO:

  		return nilfs_ioctl_get_info(inode, filp, cmd, argp,

  					    sizeof(struct nilfs_vinfo),

  					    nilfs_ioctl_do_get_vinfo);

  	case NILFS_IOCTL_GET_BDESCS:
  		return nilfs_ioctl_get_bdescs(inode, filp, cmd, argp);
  	case NILFS_IOCTL_CLEAN_SEGMENTS:
  		return nilfs_ioctl_clean_segments(inode, filp, cmd, argp);

  	case NILFS_IOCTL_SYNC:
  		return nilfs_ioctl_sync(inode, filp, cmd, argp);

  	case NILFS_IOCTL_RESIZE:
  		return nilfs_ioctl_resize(inode, filp, argp);

  	case NILFS_IOCTL_SET_ALLOC_RANGE:
  		return nilfs_ioctl_set_alloc_range(inode, argp);

  	case FITRIM:
  		return nilfs_ioctl_trim_fs(inode, argp);

  	default:
  		return -ENOTTY;
  	}
  }

  
  #ifdef CONFIG_COMPAT
  long nilfs_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
  {
  	switch (cmd) {
  	case FS_IOC32_GETFLAGS:
  		cmd = FS_IOC_GETFLAGS;
  		break;
  	case FS_IOC32_SETFLAGS:
  		cmd = FS_IOC_SETFLAGS;
  		break;
  	case FS_IOC32_GETVERSION:
  		cmd = FS_IOC_GETVERSION;
  		break;

  	case NILFS_IOCTL_CHANGE_CPMODE:
  	case NILFS_IOCTL_DELETE_CHECKPOINT:
  	case NILFS_IOCTL_GET_CPINFO:
  	case NILFS_IOCTL_GET_CPSTAT:
  	case NILFS_IOCTL_GET_SUINFO:

  	case NILFS_IOCTL_SET_SUINFO:

  	case NILFS_IOCTL_GET_SUSTAT:
  	case NILFS_IOCTL_GET_VINFO:
  	case NILFS_IOCTL_GET_BDESCS:
  	case NILFS_IOCTL_CLEAN_SEGMENTS:
  	case NILFS_IOCTL_SYNC:
  	case NILFS_IOCTL_RESIZE:
  	case NILFS_IOCTL_SET_ALLOC_RANGE:

  	case FITRIM:

  		break;

  	default:
  		return -ENOIOCTLCMD;
  	}
  	return nilfs_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
  }
  #endif