dquot.c

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{
	struct dquot *dquot, *empty;
	struct vfsmount *vfsmnt;

	if ((vfsmnt = lookup_vfsmnt(dev)) == (struct vfsmount *)NULL ||
	    (vfsmnt->mnt_quotas[type] == (struct file *)0))
		return(NODQUOT);
	dqstats.lookups++;
	empty = get_empty_dquot();
repeat:
	dquot = *(hash(dev, id, type));
	while (dquot) {
		if (dquot->dq_dev != dev || dquot->dq_id != id ||
		    dquot->dq_type != type) {
			dquot = dquot->dq_hash_next;
			continue;
		}
		wait_on_dquot(dquot);
		if (dquot->dq_dev != dev || dquot->dq_id != id ||
		    dquot->dq_type != type)
			goto repeat;
		if (!dquot->dq_count)
			nr_free_dquots--;
		dquot->dq_count++;
		if (empty)
			dqput(empty);
		dqstats.cache_hits++;
		return(dquot);
	}
	if (!empty)
		return(NODQUOT);
	dquot = empty;
	dquot->dq_id = id;
	dquot->dq_type = type;
	dquot->dq_dev = dev;
	dquot->dq_mnt = vfsmnt;
	put_last_free(dquot);
	insert_dquot_hash(dquot);
	read_dquot(dquot);
	return(dquot);
}

/*
 * Initialize a dquot-struct with new quota info. This is used by the
 * systemcall interface functions.
 */ 
static int set_dqblk(kdev_t dev, int id, short type, int flags, struct dqblk *dqblk)
{
	struct dquot *dquot;
	struct dqblk dq_dqblk;
	int error;

	if (dqblk == (struct dqblk *)NULL)
		return(-EFAULT);

	if (flags & QUOTA_SYSCALL) {
		if ((error = verify_area(VERIFY_READ, dqblk, sizeof(struct dqblk))) != 0)
			return(error);
		memcpy_fromfs(&dq_dqblk, dqblk, sizeof(struct dqblk));
	} else {
		memcpy(&dq_dqblk, dqblk, sizeof(struct dqblk));
	}
	if ((dquot = dqget(dev, id, type)) != NODQUOT) {
		lock_dquot(dquot);
		if (id > 0 && ((flags & SET_QUOTA) || (flags & SET_QLIMIT))) {
			dquot->dq_bhardlimit = dq_dqblk.dqb_bhardlimit;
			dquot->dq_bsoftlimit = dq_dqblk.dqb_bsoftlimit;
			dquot->dq_ihardlimit = dq_dqblk.dqb_ihardlimit;
			dquot->dq_isoftlimit = dq_dqblk.dqb_isoftlimit;
		}
		if ((flags & SET_QUOTA) || (flags & SET_USE)) {
			if (dquot->dq_isoftlimit &&
			    dquot->dq_curinodes < dquot->dq_isoftlimit &&
			    dq_dqblk.dqb_curinodes >= dquot->dq_isoftlimit)
				dquot->dq_itime = CURRENT_TIME + dquot->dq_mnt->mnt_iexp[type];
			dquot->dq_curinodes = dq_dqblk.dqb_curinodes;
			if (dquot->dq_curinodes < dquot->dq_isoftlimit)
				dquot->dq_flags &= ~DQ_INODES;
			if (dquot->dq_bsoftlimit &&
			    dquot->dq_curblocks < dquot->dq_bsoftlimit &&
			    dq_dqblk.dqb_curblocks >= dquot->dq_bsoftlimit)
				dquot->dq_btime = CURRENT_TIME + dquot->dq_mnt->mnt_bexp[type];
			dquot->dq_curblocks = dq_dqblk.dqb_curblocks;
			if (dquot->dq_curblocks < dquot->dq_bsoftlimit)
				dquot->dq_flags &= ~DQ_BLKS;
		}
		if (id == 0) {
			/* 
			 * Change in expiretimes, change them in dq_mnt.
			 */
			dquot->dq_mnt->mnt_bexp[type] = dquot->dq_btime = dq_dqblk.dqb_btime;
			dquot->dq_mnt->mnt_iexp[type] = dquot->dq_itime = dq_dqblk.dqb_itime;
		}
		if (dq_dqblk.dqb_bhardlimit == 0 && dq_dqblk.dqb_bsoftlimit == 0 &&
		    dq_dqblk.dqb_ihardlimit == 0 && dq_dqblk.dqb_isoftlimit == 0)
			dquot->dq_flags |= DQ_FAKE;
		else
			dquot->dq_flags &= ~DQ_FAKE;
		dquot->dq_flags |= DQ_MOD;
		unlock_dquot(dquot);
		dqput(dquot);
	}
	return(0);
}

static int get_quota(kdev_t dev, int id, short type, struct dqblk *dqblk)
{
	struct dquot *dquot;
	int error;

	if (has_quota_enabled(dev, type)) {
		if (dqblk == (struct dqblk *)NULL)
			return(-EFAULT);

		if ((error = verify_area(VERIFY_WRITE, dqblk, sizeof(struct dqblk))) != 0)
			return(error);

		if ((dquot = dqget(dev, id, type)) != NODQUOT) {
			memcpy_tofs(dqblk, (char *)&dquot->dq_dqb, sizeof(struct dqblk));
			dqput(dquot);
			return(0);
		}
	}
	return(-ESRCH);
}

static int get_stats(caddr_t addr)
{
	int error;

	if ((error = verify_area(VERIFY_WRITE, addr, sizeof(struct dqstats))) != 0)
		return(error);

	dqstats.allocated_dquots = nr_dquots;
	dqstats.free_dquots = nr_free_dquots;
	memcpy_tofs(addr, (caddr_t)&dqstats, sizeof(struct dqstats));
	return(0);
}

/*
 * Initialize pointer in a inode to the right dquots.
 */
void dquot_initialize(struct inode *inode, short type)
{
	unsigned int id = 0;
	short cnt;
	struct dquot *tmp;

	if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) {
		for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
			if (type != -1 && cnt != type)
				continue;
			if (!has_quota_enabled(inode->i_dev, cnt))
				continue;
			if (inode->i_dquot[cnt] == NODQUOT) {
				switch (cnt) {
					case USRQUOTA:
						id = inode->i_uid;
						break;
					case GRPQUOTA:
						id = inode->i_gid;
						break;
				}

				tmp = dqget(inode->i_dev, id, cnt);
				/* We may sleep in dqget(), so check it again.
				 * 	Dmitry Gorodchanin 02/11/96
				 */
				if (inode->i_dquot[cnt] != NODQUOT) {
					dqput(tmp);
					continue;
				} 
				inode->i_dquot[cnt] = tmp;
				inode->i_flags |= S_WRITE;
			}
		}
	}
}

void dquot_drop(struct inode *inode)
{
	short cnt;
	struct dquot * tmp;

	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (inode->i_dquot[cnt] == NODQUOT)
			continue;
		/* We can sleep at dqput(). So we must do it this way.
		 * 	Dmitry Gorodchanin 02/11/96
		 */
		tmp = inode->i_dquot[cnt];
		inode->i_dquot[cnt] = NODQUOT;
		dqput(tmp);
	}
	inode->i_flags &= ~S_WRITE;
}

/*
 * This is a simple algorithm that calculates the size of a file in blocks.
 * This is only used on filesystems that do not have a i_blocks count.
 */
static u_long isize_to_blocks(size_t isize, size_t blksize)
{
	u_long blocks;
	u_long indirect;

	if (!blksize)
		blksize = BLOCK_SIZE;
	blocks = (isize / blksize) + ((isize % blksize) ? 1 : 0);
	if (blocks > 10) {
		indirect = ((blocks - 11) >> 8) + 1; /* single indirect blocks */
		if (blocks > (10 + 256)) {
			indirect += ((blocks - 267) >> 16) + 1; /* double indirect blocks */
			if (blocks > (10 + 256 + (256 << 8)))
				indirect++; /* triple indirect blocks */
		}
		blocks += indirect;
	}
	return(blocks);
}

/*
 * Externally referenced functions through dquot_operations.
 */
int dquot_alloc_block(const struct inode *inode, unsigned long number)
{
	unsigned short cnt;

	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (inode->i_dquot[cnt] == NODQUOT)
			continue;
		if (check_bdq(inode->i_dquot[cnt], cnt, number))
			return(NO_QUOTA);
	}
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (inode->i_dquot[cnt] == NODQUOT)
			continue;
		dquot_incr_blocks(inode->i_dquot[cnt], number);
	}
	return(QUOTA_OK);
}

int dquot_alloc_inode(const struct inode *inode, unsigned long number)
{
	unsigned short cnt;

	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (inode->i_dquot[cnt] == NODQUOT)
			continue;
		if (check_idq(inode->i_dquot[cnt], cnt, number))
			return(NO_QUOTA);
	}
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (inode->i_dquot[cnt] == NODQUOT)
			continue;
		dquot_incr_inodes(inode->i_dquot[cnt], number);
	}
	return(QUOTA_OK);
}

void dquot_free_block(const struct inode *inode, unsigned long number)
{
	unsigned short cnt;

	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (inode->i_dquot[cnt] == NODQUOT)
			continue;
		dquot_decr_blocks(inode->i_dquot[cnt], number);
	}
}

void dquot_free_inode(const struct inode *inode, unsigned long number)
{
	unsigned short cnt;

	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (inode->i_dquot[cnt] == NODQUOT)
			continue;
		dquot_decr_inodes(inode->i_dquot[cnt], number);
	}
}

/*
 * Transfer the number of inode and blocks from one diskquota to an other.
 */
int dquot_transfer(struct inode *inode, struct iattr *iattr, char direction)
{
	unsigned long blocks;
	struct dquot *transfer_from[MAXQUOTAS];
	struct dquot *transfer_to[MAXQUOTAS];
	short cnt, disc;

	/*
	 * Find out if this filesystems uses i_blocks.
	 */
	if (inode->i_blksize == 0)
		blocks = isize_to_blocks(inode->i_size, BLOCK_SIZE);
	else
		blocks = (inode->i_blocks / 2);

	/*
	 * Build the transfer_from and transfer_to lists and check quotas to see
	 * if operation is permitted.
	 */
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		transfer_from[cnt] = NODQUOT;
		transfer_to[cnt] = NODQUOT;

		if (!has_quota_enabled(inode->i_dev, cnt))
			continue;

		switch (cnt) {
			case USRQUOTA:
				if (inode->i_uid == iattr->ia_uid)
					continue;
				transfer_from[cnt] = dqget(inode->i_dev, (direction) ? iattr->ia_uid : inode->i_uid, cnt);
				transfer_to[cnt] = dqget(inode->i_dev, (direction) ? inode->i_uid : iattr->ia_uid, cnt);
				break;
			case GRPQUOTA:
				if (inode->i_gid == iattr->ia_gid)
					continue;
				transfer_from[cnt] = dqget(inode->i_dev, (direction) ? iattr->ia_gid : inode->i_gid, cnt);
				transfer_to[cnt] = dqget(inode->i_dev, (direction) ? inode->i_gid : iattr->ia_gid, cnt);
				break;
		}

		if (check_idq(transfer_to[cnt], cnt, 1) == NO_QUOTA ||
		    check_bdq(transfer_to[cnt], cnt, blocks) == NO_QUOTA) {
			for (disc = 0; disc <= cnt; disc++) {
				dqput(transfer_from[disc]);
				dqput(transfer_to[disc]);
			}
			return(NO_QUOTA);
		}
	}

	/*
	 * Finally perform the needed transfer from transfer_from to transfer_to.
	 * And release any pointer to dquots not needed anymore.
	 */
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		/*
		 * Skip changes for same uid or gid or for non-existing quota-type.
		 */
		if (transfer_from[cnt] == NODQUOT && transfer_to[cnt] == NODQUOT)
			continue;

		if (transfer_from[cnt] != NODQUOT) {
			dquot_decr_inodes(transfer_from[cnt], 1);
			dquot_decr_blocks(transfer_from[cnt], blocks);
		}
		if (transfer_to[cnt] != NODQUOT) {
			dquot_incr_inodes(transfer_to[cnt], 1);
			dquot_incr_blocks(transfer_to[cnt], blocks);
		}
		if (inode->i_dquot[cnt] != NODQUOT) {
			dqput(transfer_from[cnt]);
			dqput(inode->i_dquot[cnt]);
			inode->i_dquot[cnt] = transfer_to[cnt];
		} else {
			dqput(transfer_from[cnt]);
			dqput(transfer_to[cnt]);
		}
	}
	return(QUOTA_OK);
}

void dquot_init(void)
{
	printk(KERN_NOTICE "VFS: Diskquotas version %s initialized\r\n",
	       __DQUOT_VERSION__);
	memset(hash_table, 0, sizeof(hash_table));
	memset((caddr_t)&dqstats, 0, sizeof(dqstats));
	first_dquot = NODQUOT;
}

/*
 * Definitions of diskquota operations.
 */
struct dquot_operations dquot_operations = {
	dquot_initialize,
	dquot_drop,
	dquot_alloc_block,
	dquot_alloc_inode,
	dquot_free_block,
	dquot_free_inode,
	dquot_transfer
};

/*
 * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
 */
int quota_off(kdev_t dev, short type)
{
	struct vfsmount *vfsmnt;
	short cnt;

	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
		if (type != -1 && cnt != type)
			continue;
		if ((vfsmnt = lookup_vfsmnt(dev)) == (struct vfsmount *)NULL ||
	     	     vfsmnt->mnt_quotas[cnt] == (struct file *)NULL)
			continue;
		vfsmnt->mnt_sb->dq_op = (struct dquot_operations *)NULL;
		reset_dquot_ptrs(dev, cnt);
		invalidate_dquots(dev, cnt);
		close_fp(vfsmnt->mnt_quotas[cnt]);
		vfsmnt->mnt_quotas[cnt] = (struct file *)NULL;
		vfsmnt->mnt_iexp[cnt] = vfsmnt->mnt_bexp[cnt] = (time_t)NULL;
	}
	return(0);
}

int quota_on(kdev_t dev, short type, char *path)
{
	struct file *filp = (struct file *)NULL;
	struct vfsmount *vfsmnt;
	struct inode *inode;
	struct dquot *dquot;
	char *tmp;
	int error;

	if ((vfsmnt = lookup_vfsmnt(dev)) == (struct vfsmount *)NULL)
		return(-ENODEV);
	if (vfsmnt->mnt_quotas[type] != (struct file *)NULL)
		return(-EBUSY);
	if ((error = getname(path, &tmp)) != 0)
		return(error);
	error = open_namei(tmp, O_RDWR, 0600, &inode, 0);
	putname(tmp);
	if (error)
		return(error);
	if (!S_ISREG(inode->i_mode)) {
		iput(inode);
		return(-EACCES);
	}
	if ((filp = get_empty_filp()) != (struct file *)NULL) {
		filp->f_mode = (O_RDWR + 1) & O_ACCMODE;
		filp->f_flags = O_RDWR;
		filp->f_inode = inode;
		filp->f_pos = 0;
		filp->f_reada = 0;
		filp->f_op = inode->i_op->default_file_ops;
		if (filp->f_op->read || filp->f_op->write) {
			if ((error = get_write_access(inode)) == 0) {
				if (filp->f_op && filp->f_op->open)
					error = filp->f_op->open(inode, filp);
				if (error == 0) {
					vfsmnt->mnt_quotas[type] = filp;
					dquot = dqget(dev, 0, type);
					vfsmnt->mnt_iexp[type] = (dquot) ? dquot->dq_itime : MAX_IQ_TIME;
					vfsmnt->mnt_bexp[type] = (dquot) ? dquot->dq_btime : MAX_DQ_TIME;
					dqput(dquot);
					vfsmnt->mnt_sb->dq_op = &dquot_operations;
					add_dquot_ref(dev, type);
					return(0);
				}
				put_write_access(inode);
			}
		} else
			error = -EIO;
	  filp->f_count--;
	} else
		error = -EMFILE;
	iput(inode);
	return(error);
}

/*
 * Ok this is the systemcall interface, this communicates with
 * the userlevel programs. Currently this only supports diskquota
 * calls. Maybe we need to add the process quotas etc in the future.
 * But we probably better use rlimits for that.
 */
asmlinkage int sys_quotactl(int cmd, const char *special, int id, caddr_t addr)
{
	int cmds = 0, type = 0, flags = 0;
	struct inode *ino;
	kdev_t dev;

	cmds = cmd >> SUBCMDSHIFT;
	type = cmd & SUBCMDMASK;

	if ((u_int) type >= MAXQUOTAS)
		return(-EINVAL);
	switch (cmds) {
		case Q_SYNC:
		case Q_GETSTATS:
			break;
		case Q_GETQUOTA:
			if (((type == USRQUOTA && current->uid != id) ||
			     (type == GRPQUOTA && current->gid != id)) && !fsuser())
				return(-EPERM);
			break;
		default:
			if (!fsuser())
				return(-EPERM);
	}

	if (special == (char *)NULL && (cmds == Q_SYNC || cmds == Q_GETSTATS))
		dev = 0;
	else {
		if (namei(special, &ino))
			return(-EINVAL);
		dev = ino->i_rdev;
		if (!S_ISBLK(ino->i_mode)) {
			iput(ino);
			return(-ENOTBLK);
		}
		iput(ino);
	}

	switch (cmds) {
		case Q_QUOTAON:
			return(quota_on(dev, type, (char *) addr));
		case Q_QUOTAOFF:
			return(quota_off(dev, type));
		case Q_GETQUOTA:
			return(get_quota(dev, id, type, (struct dqblk *) addr));
		case Q_SETQUOTA:
			flags |= SET_QUOTA;
			break;
		case Q_SETUSE:
			flags |= SET_USE;
			break;
		case Q_SETQLIM:
			flags |= SET_QLIMIT;
			break;
		case Q_SYNC:
			return(sync_dquots(dev, type));
		case Q_GETSTATS:
			return(get_stats(addr));
		default:
			return(-EINVAL);
	}

	if (id & ~0xFFFF)
		return(-EINVAL);

	flags |= QUOTA_SYSCALL;
	if (has_quota_enabled(dev, type))
		return(set_dqblk(dev, id, type, flags, (struct dqblk *) addr));
	return(-ESRCH);
}