fs/quota.c - kernel/msm-4.9 - Gitiles

 /*
  * 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/kernel.h>
 #include <linux/smp_lock.h>
 #include <linux/security.h>
 #include <linux/syscalls.h>
 #include <linux/buffer_head.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;
 	struct inode *discard[MAXQUOTAS];

 	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. We need i_sem and so we could
 	 * not do it inside dqonoff_sem. Moreover we need to be carefull
 	 * about races with quotaoff() (that is the reason why we have own
 	 * reference to inode). */
 	down(&sb_dqopt(sb)->dqonoff_sem);
 	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 		discard[cnt] = NULL;
 		if (type != -1 && cnt != type)
 			continue;
 		if (!sb_has_quota_enabled(sb, cnt))
 			continue;
 		discard[cnt] = igrab(sb_dqopt(sb)->files[cnt]);
 	}
 	up(&sb_dqopt(sb)->dqonoff_sem);
 	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 		if (discard[cnt]) {
 			down(&discard[cnt]->i_sem);
 			truncate_inode_pages(&discard[cnt]->i_data, 0);
 			up(&discard[cnt]->i_sem);
 			iput(discard[cnt]);
 		}
 	}
 }

 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;
 }

 /*
  * 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;
 	struct block_device *bdev;
 	char *tmp;
 	int ret;

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

 	if (cmds != Q_SYNC || special) {
 		tmp = getname(special);
 		if (IS_ERR(tmp))
 			return PTR_ERR(tmp);
 		bdev = lookup_bdev(tmp);
 		putname(tmp);
 		if (IS_ERR(bdev))
 			return PTR_ERR(bdev);
 		sb = get_super(bdev);
 		bdput(bdev);
 		if (!sb)
 			return -ENODEV;
 	}

 	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;
 }
	/*
	* 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/kernel.h>
	#include <linux/smp_lock.h>
	#include <linux/security.h>
	#include <linux/syscalls.h>
	#include <linux/buffer_head.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;
	struct inode *discard[MAXQUOTAS];

	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. We need i_sem and so we could
	* not do it inside dqonoff_sem. Moreover we need to be carefull
	* about races with quotaoff() (that is the reason why we have own
	* reference to inode). */
	down(&sb_dqopt(sb)->dqonoff_sem);
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
	discard[cnt] = NULL;
	if (type != -1 && cnt != type)
	continue;
	if (!sb_has_quota_enabled(sb, cnt))
	continue;
	discard[cnt] = igrab(sb_dqopt(sb)->files[cnt]);
	}
	up(&sb_dqopt(sb)->dqonoff_sem);
	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
	if (discard[cnt]) {
	down(&discard[cnt]->i_sem);
	truncate_inode_pages(&discard[cnt]->i_data, 0);
	up(&discard[cnt]->i_sem);
	iput(discard[cnt]);
	}
	}
	}

	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;
	}

	/*
	* 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;
	struct block_device *bdev;
	char *tmp;
	int ret;

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

	if (cmds != Q_SYNC \|\| special) {
	tmp = getname(special);
	if (IS_ERR(tmp))
	return PTR_ERR(tmp);
	bdev = lookup_bdev(tmp);
	putname(tmp);
	if (IS_ERR(bdev))
	return PTR_ERR(bdev);
	sb = get_super(bdev);
	bdput(bdev);
	if (!sb)
	return -ENODEV;
	}

	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;
	}