| /* |
| * 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/security.h> |
| #include <linux/syscalls.h> |
| #include <linux/buffer_head.h> |
| #include <linux/capability.h> |
| #include <linux/quotaops.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; |
| |
| 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. |
| */ |
| mutex_lock(&sb_dqopt(sb)->dqonoff_mutex); |
| for (cnt = 0; cnt < MAXQUOTAS; cnt++) { |
| if (type != -1 && cnt != type) |
| continue; |
| if (!sb_has_quota_enabled(sb, cnt)) |
| continue; |
| mutex_lock_nested(&sb_dqopt(sb)->files[cnt]->i_mutex, I_MUTEX_QUOTA); |
| truncate_inode_pages(&sb_dqopt(sb)->files[cnt]->i_data, 0); |
| mutex_unlock(&sb_dqopt(sb)->files[cnt]->i_mutex); |
| } |
| mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex); |
| } |
| |
| 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; |
| } |
| |
| /* |
| * look up a superblock on which quota ops will be performed |
| * - use the name of a block device to find the superblock thereon |
| */ |
| static inline struct super_block *quotactl_block(const char __user *special) |
| { |
| #ifdef CONFIG_BLOCK |
| struct block_device *bdev; |
| struct super_block *sb; |
| char *tmp = getname(special); |
| |
| if (IS_ERR(tmp)) |
| return ERR_PTR(PTR_ERR(tmp)); |
| bdev = lookup_bdev(tmp); |
| putname(tmp); |
| if (IS_ERR(bdev)) |
| return ERR_PTR(PTR_ERR(bdev)); |
| sb = get_super(bdev); |
| bdput(bdev); |
| if (!sb) |
| return ERR_PTR(-ENODEV); |
| |
| return sb; |
| #else |
| return ERR_PTR(-ENODEV); |
| #endif |
| } |
| |
| /* |
| * 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; |
| int ret; |
| |
| cmds = cmd >> SUBCMDSHIFT; |
| type = cmd & SUBCMDMASK; |
| |
| if (cmds != Q_SYNC || special) { |
| sb = quotactl_block(special); |
| if (IS_ERR(sb)) |
| return PTR_ERR(sb); |
| } |
| |
| 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; |
| } |