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-rw-r--r--fs/quota.c382
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;
+}
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