/*
   * Quota code necessary even when VFS quota support is not compiled
   * into the kernel.  The interesting stuff is over in dquot.c, here
   * we have symbols for initial quotactl(2) handling, the sysctl(2)
   * variables, etc - things needed even when quota support disabled.
   */
  
  #include <linux/fs.h>
  #include <linux/namei.h>
  #include <linux/slab.h>
  #include <asm/current.h>
  #include <asm/uaccess.h>

  #include <linux/compat.h>

  #include <linux/kernel.h>

  #include <linux/security.h>
  #include <linux/syscalls.h>
  #include <linux/buffer_head.h>

  #include <linux/capability.h>

  #include <linux/quotaops.h>

  #include <linux/types.h>

  
  /* Check validity of generic quotactl commands */
  static int generic_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
  {
  	if (type >= MAXQUOTAS)
  		return -EINVAL;
  	if (!sb && cmd != Q_SYNC)
  		return -ENODEV;
  	/* Is operation supported? */
  	if (sb && !sb->s_qcop)
  		return -ENOSYS;
  
  	switch (cmd) {
  		case Q_GETFMT:
  			break;
  		case Q_QUOTAON:
  			if (!sb->s_qcop->quota_on)
  				return -ENOSYS;
  			break;
  		case Q_QUOTAOFF:
  			if (!sb->s_qcop->quota_off)
  				return -ENOSYS;
  			break;
  		case Q_SETINFO:
  			if (!sb->s_qcop->set_info)
  				return -ENOSYS;
  			break;
  		case Q_GETINFO:
  			if (!sb->s_qcop->get_info)
  				return -ENOSYS;
  			break;
  		case Q_SETQUOTA:
  			if (!sb->s_qcop->set_dqblk)
  				return -ENOSYS;
  			break;
  		case Q_GETQUOTA:
  			if (!sb->s_qcop->get_dqblk)
  				return -ENOSYS;
  			break;
  		case Q_SYNC:
  			if (sb && !sb->s_qcop->quota_sync)
  				return -ENOSYS;
  			break;
  		default:
  			return -EINVAL;
  	}
  
  	/* Is quota turned on for commands which need it? */
  	switch (cmd) {
  		case Q_GETFMT:
  		case Q_GETINFO:
  		case Q_QUOTAOFF:
  		case Q_SETINFO:
  		case Q_SETQUOTA:
  		case Q_GETQUOTA:
  			/* This is just informative test so we are satisfied without a lock */
  			if (!sb_has_quota_enabled(sb, type))
  				return -ESRCH;
  	}
  
  	/* Check privileges */
  	if (cmd == Q_GETQUOTA) {
  		if (((type == USRQUOTA && current->euid != id) ||
  		     (type == GRPQUOTA && !in_egroup_p(id))) &&
  		    !capable(CAP_SYS_ADMIN))
  			return -EPERM;
  	}
  	else if (cmd != Q_GETFMT && cmd != Q_SYNC && cmd != Q_GETINFO)
  		if (!capable(CAP_SYS_ADMIN))
  			return -EPERM;
  
  	return 0;
  }
  
  /* Check validity of XFS Quota Manager commands */
  static int xqm_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
  {
  	if (type >= XQM_MAXQUOTAS)
  		return -EINVAL;
  	if (!sb)
  		return -ENODEV;
  	if (!sb->s_qcop)
  		return -ENOSYS;
  
  	switch (cmd) {
  		case Q_XQUOTAON:
  		case Q_XQUOTAOFF:
  		case Q_XQUOTARM:
  			if (!sb->s_qcop->set_xstate)
  				return -ENOSYS;
  			break;
  		case Q_XGETQSTAT:
  			if (!sb->s_qcop->get_xstate)
  				return -ENOSYS;
  			break;
  		case Q_XSETQLIM:
  			if (!sb->s_qcop->set_xquota)
  				return -ENOSYS;
  			break;
  		case Q_XGETQUOTA:
  			if (!sb->s_qcop->get_xquota)
  				return -ENOSYS;
  			break;

  		case Q_XQUOTASYNC:
  			if (!sb->s_qcop->quota_sync)
  				return -ENOSYS;
  			break;

  		default:
  			return -EINVAL;
  	}
  
  	/* Check privileges */
  	if (cmd == Q_XGETQUOTA) {
  		if (((type == XQM_USRQUOTA && current->euid != id) ||
  		     (type == XQM_GRPQUOTA && !in_egroup_p(id))) &&
  		     !capable(CAP_SYS_ADMIN))
  			return -EPERM;

  	} else if (cmd != Q_XGETQSTAT && cmd != Q_XQUOTASYNC) {

  		if (!capable(CAP_SYS_ADMIN))
  			return -EPERM;
  	}
  
  	return 0;
  }
  
  static int check_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
  {
  	int error;
  
  	if (XQM_COMMAND(cmd))
  		error = xqm_quotactl_valid(sb, type, cmd, id);
  	else
  		error = generic_quotactl_valid(sb, type, cmd, id);
  	if (!error)
  		error = security_quotactl(cmd, type, id, sb);
  	return error;
  }

  static void quota_sync_sb(struct super_block *sb, int type)
  {
  	int cnt;

  
  	sb->s_qcop->quota_sync(sb, type);
  	/* This is not very clever (and fast) but currently I don't know about
  	 * any other simple way of getting quota data to disk and we must get
  	 * them there for userspace to be visible... */
  	if (sb->s_op->sync_fs)
  		sb->s_op->sync_fs(sb, 1);
  	sync_blockdev(sb->s_bdev);

  	/*
  	 * Now when everything is written we can discard the pagecache so
  	 * that userspace sees the changes.
  	 */

  	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);

  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {

  		if (type != -1 && cnt != type)
  			continue;
  		if (!sb_has_quota_enabled(sb, cnt))
  			continue;

  		mutex_lock_nested(&sb_dqopt(sb)->files[cnt]->i_mutex, I_MUTEX_QUOTA);
  		truncate_inode_pages(&sb_dqopt(sb)->files[cnt]->i_data, 0);
  		mutex_unlock(&sb_dqopt(sb)->files[cnt]->i_mutex);

  	}

  	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);

  }
  
  void sync_dquots(struct super_block *sb, int type)
  {

  	int cnt, dirty;

  	if (sb) {
  		if (sb->s_qcop->quota_sync)
  			quota_sync_sb(sb, type);

  		return;

  	}

  
  	spin_lock(&sb_lock);
  restart:
  	list_for_each_entry(sb, &super_blocks, s_list) {
  		/* This test just improves performance so it needn't be reliable... */
  		for (cnt = 0, dirty = 0; cnt < MAXQUOTAS; cnt++)
  			if ((type == cnt || type == -1) && sb_has_quota_enabled(sb, cnt)
  			    && info_any_dirty(&sb_dqopt(sb)->info[cnt]))
  				dirty = 1;
  		if (!dirty)
  			continue;
  		sb->s_count++;
  		spin_unlock(&sb_lock);
  		down_read(&sb->s_umount);
  		if (sb->s_root && sb->s_qcop->quota_sync)
  			quota_sync_sb(sb, type);
  		up_read(&sb->s_umount);
  		spin_lock(&sb_lock);
  		if (__put_super_and_need_restart(sb))
  			goto restart;

  	}

  	spin_unlock(&sb_lock);

  }
  
  /* Copy parameters and call proper function */
  static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id, void __user *addr)
  {
  	int ret;
  
  	switch (cmd) {
  		case Q_QUOTAON: {
  			char *pathname;
  
  			if (IS_ERR(pathname = getname(addr)))
  				return PTR_ERR(pathname);
  			ret = sb->s_qcop->quota_on(sb, type, id, pathname);
  			putname(pathname);
  			return ret;
  		}
  		case Q_QUOTAOFF:
  			return sb->s_qcop->quota_off(sb, type);
  
  		case Q_GETFMT: {
  			__u32 fmt;
  
  			down_read(&sb_dqopt(sb)->dqptr_sem);
  			if (!sb_has_quota_enabled(sb, type)) {
  				up_read(&sb_dqopt(sb)->dqptr_sem);
  				return -ESRCH;
  			}
  			fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
  			up_read(&sb_dqopt(sb)->dqptr_sem);
  			if (copy_to_user(addr, &fmt, sizeof(fmt)))
  				return -EFAULT;
  			return 0;
  		}
  		case Q_GETINFO: {
  			struct if_dqinfo info;
  
  			if ((ret = sb->s_qcop->get_info(sb, type, &info)))
  				return ret;
  			if (copy_to_user(addr, &info, sizeof(info)))
  				return -EFAULT;
  			return 0;
  		}
  		case Q_SETINFO: {
  			struct if_dqinfo info;
  
  			if (copy_from_user(&info, addr, sizeof(info)))
  				return -EFAULT;
  			return sb->s_qcop->set_info(sb, type, &info);
  		}
  		case Q_GETQUOTA: {
  			struct if_dqblk idq;
  
  			if ((ret = sb->s_qcop->get_dqblk(sb, type, id, &idq)))
  				return ret;
  			if (copy_to_user(addr, &idq, sizeof(idq)))
  				return -EFAULT;
  			return 0;
  		}
  		case Q_SETQUOTA: {
  			struct if_dqblk idq;
  
  			if (copy_from_user(&idq, addr, sizeof(idq)))
  				return -EFAULT;
  			return sb->s_qcop->set_dqblk(sb, type, id, &idq);
  		}
  		case Q_SYNC:
  			sync_dquots(sb, type);
  			return 0;
  
  		case Q_XQUOTAON:
  		case Q_XQUOTAOFF:
  		case Q_XQUOTARM: {
  			__u32 flags;
  
  			if (copy_from_user(&flags, addr, sizeof(flags)))
  				return -EFAULT;
  			return sb->s_qcop->set_xstate(sb, flags, cmd);
  		}
  		case Q_XGETQSTAT: {
  			struct fs_quota_stat fqs;
  		
  			if ((ret = sb->s_qcop->get_xstate(sb, &fqs)))
  				return ret;
  			if (copy_to_user(addr, &fqs, sizeof(fqs)))
  				return -EFAULT;
  			return 0;
  		}
  		case Q_XSETQLIM: {
  			struct fs_disk_quota fdq;
  
  			if (copy_from_user(&fdq, addr, sizeof(fdq)))
  				return -EFAULT;
  		       return sb->s_qcop->set_xquota(sb, type, id, &fdq);
  		}
  		case Q_XGETQUOTA: {
  			struct fs_disk_quota fdq;
  
  			if ((ret = sb->s_qcop->get_xquota(sb, type, id, &fdq)))
  				return ret;
  			if (copy_to_user(addr, &fdq, sizeof(fdq)))
  				return -EFAULT;
  			return 0;
  		}

  		case Q_XQUOTASYNC:
  			return sb->s_qcop->quota_sync(sb, type);

  		/* We never reach here unless validity check is broken */
  		default:
  			BUG();
  	}
  	return 0;
  }
  
  /*

   * look up a superblock on which quota ops will be performed
   * - use the name of a block device to find the superblock thereon
   */
  static inline struct super_block *quotactl_block(const char __user *special)
  {
  #ifdef CONFIG_BLOCK
  	struct block_device *bdev;
  	struct super_block *sb;
  	char *tmp = getname(special);
  
  	if (IS_ERR(tmp))
  		return ERR_PTR(PTR_ERR(tmp));
  	bdev = lookup_bdev(tmp);
  	putname(tmp);
  	if (IS_ERR(bdev))
  		return ERR_PTR(PTR_ERR(bdev));
  	sb = get_super(bdev);
  	bdput(bdev);
  	if (!sb)
  		return ERR_PTR(-ENODEV);
  
  	return sb;
  #else
  	return ERR_PTR(-ENODEV);
  #endif
  }
  
  /*

   * This is the system call interface. This communicates with
   * the user-level programs. Currently this only supports diskquota
   * calls. Maybe we need to add the process quotas etc. in the future,
   * but we probably should use rlimits for that.
   */
  asmlinkage long sys_quotactl(unsigned int cmd, const char __user *special, qid_t id, void __user *addr)
  {
  	uint cmds, type;
  	struct super_block *sb = NULL;

  	int ret;
  
  	cmds = cmd >> SUBCMDSHIFT;
  	type = cmd & SUBCMDMASK;
  
  	if (cmds != Q_SYNC || special) {

  		sb = quotactl_block(special);
  		if (IS_ERR(sb))
  			return PTR_ERR(sb);

  	}
  
  	ret = check_quotactl_valid(sb, type, cmds, id);
  	if (ret >= 0)
  		ret = do_quotactl(sb, type, cmds, id, addr);
  	if (sb)
  		drop_super(sb);
  
  	return ret;
  }

  #if defined(CONFIG_COMPAT_FOR_U64_ALIGNMENT)

  /*
   * This code works only for 32 bit quota tools over 64 bit OS (x86_64, ia64)
   * and is necessary due to alignment problems.
   */
  struct compat_if_dqblk {
  	compat_u64 dqb_bhardlimit;
  	compat_u64 dqb_bsoftlimit;
  	compat_u64 dqb_curspace;
  	compat_u64 dqb_ihardlimit;
  	compat_u64 dqb_isoftlimit;
  	compat_u64 dqb_curinodes;
  	compat_u64 dqb_btime;
  	compat_u64 dqb_itime;
  	compat_uint_t dqb_valid;
  };
  
  /* XFS structures */
  struct compat_fs_qfilestat {
  	compat_u64 dqb_bhardlimit;
  	compat_u64 qfs_nblks;
  	compat_uint_t qfs_nextents;
  };
  
  struct compat_fs_quota_stat {
  	__s8		qs_version;
  	__u16		qs_flags;
  	__s8		qs_pad;
  	struct compat_fs_qfilestat	qs_uquota;
  	struct compat_fs_qfilestat	qs_gquota;
  	compat_uint_t	qs_incoredqs;
  	compat_int_t	qs_btimelimit;
  	compat_int_t	qs_itimelimit;
  	compat_int_t	qs_rtbtimelimit;
  	__u16		qs_bwarnlimit;
  	__u16		qs_iwarnlimit;
  };
  
  asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
  						qid_t id, void __user *addr)
  {
  	unsigned int cmds;
  	struct if_dqblk __user *dqblk;
  	struct compat_if_dqblk __user *compat_dqblk;
  	struct fs_quota_stat __user *fsqstat;
  	struct compat_fs_quota_stat __user *compat_fsqstat;
  	compat_uint_t data;
  	u16 xdata;
  	long ret;
  
  	cmds = cmd >> SUBCMDSHIFT;
  
  	switch (cmds) {
  	case Q_GETQUOTA:
  		dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
  		compat_dqblk = addr;
  		ret = sys_quotactl(cmd, special, id, dqblk);
  		if (ret)
  			break;
  		if (copy_in_user(compat_dqblk, dqblk, sizeof(*compat_dqblk)) ||
  			get_user(data, &dqblk->dqb_valid) ||
  			put_user(data, &compat_dqblk->dqb_valid))
  			ret = -EFAULT;
  		break;
  	case Q_SETQUOTA:
  		dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
  		compat_dqblk = addr;
  		ret = -EFAULT;
  		if (copy_in_user(dqblk, compat_dqblk, sizeof(*compat_dqblk)) ||
  			get_user(data, &compat_dqblk->dqb_valid) ||
  			put_user(data, &dqblk->dqb_valid))
  			break;
  		ret = sys_quotactl(cmd, special, id, dqblk);
  		break;
  	case Q_XGETQSTAT:
  		fsqstat = compat_alloc_user_space(sizeof(struct fs_quota_stat));
  		compat_fsqstat = addr;
  		ret = sys_quotactl(cmd, special, id, fsqstat);
  		if (ret)
  			break;
  		ret = -EFAULT;
  		/* Copying qs_version, qs_flags, qs_pad */
  		if (copy_in_user(compat_fsqstat, fsqstat,
  			offsetof(struct compat_fs_quota_stat, qs_uquota)))
  			break;
  		/* Copying qs_uquota */
  		if (copy_in_user(&compat_fsqstat->qs_uquota,
  			&fsqstat->qs_uquota,
  			sizeof(compat_fsqstat->qs_uquota)) ||
  			get_user(data, &fsqstat->qs_uquota.qfs_nextents) ||
  			put_user(data, &compat_fsqstat->qs_uquota.qfs_nextents))
  			break;
  		/* Copying qs_gquota */
  		if (copy_in_user(&compat_fsqstat->qs_gquota,
  			&fsqstat->qs_gquota,
  			sizeof(compat_fsqstat->qs_gquota)) ||
  			get_user(data, &fsqstat->qs_gquota.qfs_nextents) ||
  			put_user(data, &compat_fsqstat->qs_gquota.qfs_nextents))
  			break;
  		/* Copying the rest */
  		if (copy_in_user(&compat_fsqstat->qs_incoredqs,
  			&fsqstat->qs_incoredqs,
  			sizeof(struct compat_fs_quota_stat) -
  			offsetof(struct compat_fs_quota_stat, qs_incoredqs)) ||
  			get_user(xdata, &fsqstat->qs_iwarnlimit) ||
  			put_user(xdata, &compat_fsqstat->qs_iwarnlimit))
  			break;
  		ret = 0;
  		break;
  	default:
  		ret = sys_quotactl(cmd, special, id, addr);
  	}
  	return ret;
  }
  #endif