342 lines
7.8 KiB
C
342 lines
7.8 KiB
C
/*
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* Quota code necessary even when VFS quota support is not compiled
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* into the kernel. The interesting stuff is over in dquot.c, here
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* we have symbols for initial quotactl(2) handling, the sysctl(2)
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* variables, etc - things needed even when quota support disabled.
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*/
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#include <linux/fs.h>
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#include <linux/namei.h>
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#include <linux/slab.h>
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#include <asm/current.h>
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#include <asm/uaccess.h>
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#include <linux/kernel.h>
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#include <linux/security.h>
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#include <linux/syscalls.h>
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#include <linux/buffer_head.h>
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#include <linux/capability.h>
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#include <linux/quotaops.h>
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#include <linux/types.h>
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#include <linux/writeback.h>
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static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
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qid_t id)
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{
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switch (cmd) {
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/* these commands do not require any special privilegues */
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case Q_GETFMT:
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case Q_SYNC:
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case Q_GETINFO:
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case Q_XGETQSTAT:
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case Q_XQUOTASYNC:
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break;
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/* allow to query information for dquots we "own" */
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case Q_GETQUOTA:
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case Q_XGETQUOTA:
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if ((type == USRQUOTA && current_euid() == id) ||
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(type == GRPQUOTA && in_egroup_p(id)))
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break;
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/*FALLTHROUGH*/
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default:
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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}
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return security_quotactl(cmd, type, id, sb);
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}
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static int quota_sync_all(int type)
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{
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struct super_block *sb;
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int ret;
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if (type >= MAXQUOTAS)
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return -EINVAL;
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ret = security_quotactl(Q_SYNC, type, 0, NULL);
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if (ret)
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return ret;
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spin_lock(&sb_lock);
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restart:
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list_for_each_entry(sb, &super_blocks, s_list) {
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if (!sb->s_qcop || !sb->s_qcop->quota_sync)
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continue;
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sb->s_count++;
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spin_unlock(&sb_lock);
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down_read(&sb->s_umount);
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if (sb->s_root)
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sb->s_qcop->quota_sync(sb, type, 1);
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up_read(&sb->s_umount);
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spin_lock(&sb_lock);
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if (__put_super_and_need_restart(sb))
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goto restart;
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}
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spin_unlock(&sb_lock);
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return 0;
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}
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static int quota_quotaon(struct super_block *sb, int type, int cmd, qid_t id,
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void __user *addr)
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{
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char *pathname;
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int ret = -ENOSYS;
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pathname = getname(addr);
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if (IS_ERR(pathname))
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return PTR_ERR(pathname);
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if (sb->s_qcop->quota_on)
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ret = sb->s_qcop->quota_on(sb, type, id, pathname, 0);
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putname(pathname);
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return ret;
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}
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static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
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{
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__u32 fmt;
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down_read(&sb_dqopt(sb)->dqptr_sem);
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if (!sb_has_quota_active(sb, type)) {
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up_read(&sb_dqopt(sb)->dqptr_sem);
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return -ESRCH;
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}
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fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
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up_read(&sb_dqopt(sb)->dqptr_sem);
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if (copy_to_user(addr, &fmt, sizeof(fmt)))
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return -EFAULT;
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return 0;
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}
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static int quota_getinfo(struct super_block *sb, int type, void __user *addr)
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{
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struct if_dqinfo info;
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int ret;
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if (!sb_has_quota_active(sb, type))
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return -ESRCH;
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if (!sb->s_qcop->get_info)
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return -ENOSYS;
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ret = sb->s_qcop->get_info(sb, type, &info);
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if (!ret && copy_to_user(addr, &info, sizeof(info)))
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return -EFAULT;
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return ret;
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}
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static int quota_setinfo(struct super_block *sb, int type, void __user *addr)
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{
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struct if_dqinfo info;
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if (copy_from_user(&info, addr, sizeof(info)))
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return -EFAULT;
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if (!sb_has_quota_active(sb, type))
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return -ESRCH;
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if (!sb->s_qcop->set_info)
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return -ENOSYS;
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return sb->s_qcop->set_info(sb, type, &info);
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}
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static int quota_getquota(struct super_block *sb, int type, qid_t id,
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void __user *addr)
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{
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struct if_dqblk idq;
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int ret;
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if (!sb_has_quota_active(sb, type))
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return -ESRCH;
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if (!sb->s_qcop->get_dqblk)
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return -ENOSYS;
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ret = sb->s_qcop->get_dqblk(sb, type, id, &idq);
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if (ret)
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return ret;
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if (copy_to_user(addr, &idq, sizeof(idq)))
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return -EFAULT;
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return 0;
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}
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static int quota_setquota(struct super_block *sb, int type, qid_t id,
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void __user *addr)
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{
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struct if_dqblk idq;
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if (copy_from_user(&idq, addr, sizeof(idq)))
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return -EFAULT;
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if (!sb_has_quota_active(sb, type))
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return -ESRCH;
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if (!sb->s_qcop->set_dqblk)
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return -ENOSYS;
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return sb->s_qcop->set_dqblk(sb, type, id, &idq);
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}
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static int quota_setxstate(struct super_block *sb, int cmd, void __user *addr)
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{
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__u32 flags;
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if (copy_from_user(&flags, addr, sizeof(flags)))
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return -EFAULT;
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if (!sb->s_qcop->set_xstate)
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return -ENOSYS;
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return sb->s_qcop->set_xstate(sb, flags, cmd);
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}
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static int quota_getxstate(struct super_block *sb, void __user *addr)
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{
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struct fs_quota_stat fqs;
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int ret;
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if (!sb->s_qcop->get_xstate)
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return -ENOSYS;
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ret = sb->s_qcop->get_xstate(sb, &fqs);
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if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
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return -EFAULT;
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return ret;
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}
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static int quota_setxquota(struct super_block *sb, int type, qid_t id,
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void __user *addr)
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{
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struct fs_disk_quota fdq;
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if (copy_from_user(&fdq, addr, sizeof(fdq)))
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return -EFAULT;
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if (!sb->s_qcop->set_xquota)
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return -ENOSYS;
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return sb->s_qcop->set_xquota(sb, type, id, &fdq);
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}
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static int quota_getxquota(struct super_block *sb, int type, qid_t id,
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void __user *addr)
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{
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struct fs_disk_quota fdq;
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int ret;
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if (!sb->s_qcop->get_xquota)
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return -ENOSYS;
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ret = sb->s_qcop->get_xquota(sb, type, id, &fdq);
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if (!ret && copy_to_user(addr, &fdq, sizeof(fdq)))
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return -EFAULT;
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return ret;
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}
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/* Copy parameters and call proper function */
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static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
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void __user *addr)
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{
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int ret;
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if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS))
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return -EINVAL;
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if (!sb->s_qcop)
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return -ENOSYS;
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ret = check_quotactl_permission(sb, type, cmd, id);
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if (ret < 0)
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return ret;
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switch (cmd) {
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case Q_QUOTAON:
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return quota_quotaon(sb, type, cmd, id, addr);
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case Q_QUOTAOFF:
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if (!sb->s_qcop->quota_off)
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return -ENOSYS;
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return sb->s_qcop->quota_off(sb, type, 0);
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case Q_GETFMT:
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return quota_getfmt(sb, type, addr);
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case Q_GETINFO:
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return quota_getinfo(sb, type, addr);
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case Q_SETINFO:
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return quota_setinfo(sb, type, addr);
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case Q_GETQUOTA:
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return quota_getquota(sb, type, id, addr);
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case Q_SETQUOTA:
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return quota_setquota(sb, type, id, addr);
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case Q_SYNC:
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if (!sb->s_qcop->quota_sync)
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return -ENOSYS;
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return sb->s_qcop->quota_sync(sb, type, 1);
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case Q_XQUOTAON:
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case Q_XQUOTAOFF:
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case Q_XQUOTARM:
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return quota_setxstate(sb, cmd, addr);
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case Q_XGETQSTAT:
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return quota_getxstate(sb, addr);
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case Q_XSETQLIM:
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return quota_setxquota(sb, type, id, addr);
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case Q_XGETQUOTA:
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return quota_getxquota(sb, type, id, addr);
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case Q_XQUOTASYNC:
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/* caller already holds s_umount */
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if (sb->s_flags & MS_RDONLY)
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return -EROFS;
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writeback_inodes_sb(sb);
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return 0;
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default:
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return -EINVAL;
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}
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}
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/*
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* look up a superblock on which quota ops will be performed
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* - use the name of a block device to find the superblock thereon
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*/
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static struct super_block *quotactl_block(const char __user *special)
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{
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#ifdef CONFIG_BLOCK
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struct block_device *bdev;
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struct super_block *sb;
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char *tmp = getname(special);
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if (IS_ERR(tmp))
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return ERR_CAST(tmp);
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bdev = lookup_bdev(tmp);
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putname(tmp);
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if (IS_ERR(bdev))
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return ERR_CAST(bdev);
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sb = get_super(bdev);
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bdput(bdev);
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if (!sb)
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return ERR_PTR(-ENODEV);
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return sb;
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#else
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return ERR_PTR(-ENODEV);
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#endif
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}
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/*
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* This is the system call interface. This communicates with
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* the user-level programs. Currently this only supports diskquota
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* calls. Maybe we need to add the process quotas etc. in the future,
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* but we probably should use rlimits for that.
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*/
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SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
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qid_t, id, void __user *, addr)
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{
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uint cmds, type;
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struct super_block *sb = NULL;
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int ret;
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cmds = cmd >> SUBCMDSHIFT;
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type = cmd & SUBCMDMASK;
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/*
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* As a special case Q_SYNC can be called without a specific device.
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* It will iterate all superblocks that have quota enabled and call
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* the sync action on each of them.
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*/
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if (!special) {
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if (cmds == Q_SYNC)
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return quota_sync_all(type);
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return -ENODEV;
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}
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sb = quotactl_block(special);
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if (IS_ERR(sb))
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return PTR_ERR(sb);
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ret = do_quotactl(sb, type, cmds, id, addr);
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drop_super(sb);
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return ret;
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}
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