1 files changed, 382 insertions, 0 deletions

diff --git a/fs/quota.c b/fs/quota.c
new file mode 100644
index 0000000..3f0333a
--- /dev/null
+++ b/fs/quota.c
@@ -0,0 +1,382 @@
+/*
+ * 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;
+		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) {
+		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 struct super_block *get_super_to_sync(int type)
+{
+	struct list_head *head;
+	int cnt, dirty;
+
+restart:
+	spin_lock(&sb_lock);
+	list_for_each(head, &super_blocks) {
+		struct super_block *sb = list_entry(head, struct super_block, 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) {
+			drop_super(sb);
+			goto restart;
+		}
+		return sb;
+	}
+	spin_unlock(&sb_lock);
+	return NULL;
+}
+
+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)
+{
+	if (sb) {
+		if (sb->s_qcop->quota_sync)
+			quota_sync_sb(sb, type);
+	}
+	else {
+		while ((sb = get_super_to_sync(type)) != NULL) {
+			if (sb->s_qcop->quota_sync)
+				quota_sync_sb(sb, type);
+			drop_super(sb);
+		}
+	}
+}
+
+/* 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;
+		}
+		/* 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;
+}