|  | /* | 
|  | * 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> | 
|  | #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; | 
|  | 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_mutex and so we could | 
|  | * not do it inside dqonoff_mutex. Moreover we need to be carefull | 
|  | * about races with quotaoff() (that is the reason why we have own | 
|  | * reference to inode). */ | 
|  | mutex_lock(&sb_dqopt(sb)->dqonoff_mutex); | 
|  | 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]); | 
|  | } | 
|  | mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex); | 
|  | for (cnt = 0; cnt < MAXQUOTAS; cnt++) { | 
|  | if (discard[cnt]) { | 
|  | mutex_lock(&discard[cnt]->i_mutex); | 
|  | truncate_inode_pages(&discard[cnt]->i_data, 0); | 
|  | mutex_unlock(&discard[cnt]->i_mutex); | 
|  | 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; | 
|  | } |