BKL: Remove BKL from ncpfs
[pandora-kernel.git] / fs / ncpfs / ioctl.c
index 84a8cfc..c2a1f9a 100644 (file)
 #define NCP_PACKET_SIZE_INTERNAL 65536
 
 static int
-ncp_get_fs_info(struct ncp_server * server, struct file *file,
+ncp_get_fs_info(struct ncp_server * server, struct inode *inode,
                struct ncp_fs_info __user *arg)
 {
-       struct inode *inode = file->f_path.dentry->d_inode;
        struct ncp_fs_info info;
 
-       if (file_permission(file, MAY_WRITE) != 0
-           && current_uid() != server->m.mounted_uid)
-               return -EACCES;
-
        if (copy_from_user(&info, arg, sizeof(info)))
                return -EFAULT;
 
@@ -65,16 +60,11 @@ ncp_get_fs_info(struct ncp_server * server, struct file *file,
 }
 
 static int
-ncp_get_fs_info_v2(struct ncp_server * server, struct file *file,
+ncp_get_fs_info_v2(struct ncp_server * server, struct inode *inode,
                   struct ncp_fs_info_v2 __user * arg)
 {
-       struct inode *inode = file->f_path.dentry->d_inode;
        struct ncp_fs_info_v2 info2;
 
-       if (file_permission(file, MAY_WRITE) != 0
-           && current_uid() != server->m.mounted_uid)
-               return -EACCES;
-
        if (copy_from_user(&info2, arg, sizeof(info2)))
                return -EFAULT;
 
@@ -136,16 +126,11 @@ struct compat_ncp_privatedata_ioctl
 #define NCP_IOC_SETPRIVATEDATA_32      _IOR('n', 10, struct compat_ncp_privatedata_ioctl)
 
 static int
-ncp_get_compat_fs_info_v2(struct ncp_server * server, struct file *file,
+ncp_get_compat_fs_info_v2(struct ncp_server * server, struct inode *inode,
                   struct compat_ncp_fs_info_v2 __user * arg)
 {
-       struct inode *inode = file->f_path.dentry->d_inode;
        struct compat_ncp_fs_info_v2 info2;
 
-       if (file_permission(file, MAY_WRITE) != 0
-           && current_uid() != server->m.mounted_uid)
-               return -EACCES;
-
        if (copy_from_user(&info2, arg, sizeof(info2)))
                return -EFAULT;
 
@@ -182,11 +167,8 @@ ncp_set_charsets(struct ncp_server* server, struct ncp_nls_ioctl __user *arg)
        struct nls_table *iocharset;
        struct nls_table *oldset_io;
        struct nls_table *oldset_cp;
-
-       if (!capable(CAP_SYS_ADMIN))
-               return -EACCES;
-       if (server->root_setuped)
-               return -EBUSY;
+       int utf8;
+       int err;
 
        if (copy_from_user(&user, arg, sizeof(user)))
                return -EFAULT;
@@ -206,28 +188,40 @@ ncp_set_charsets(struct ncp_server* server, struct ncp_nls_ioctl __user *arg)
        user.iocharset[NCP_IOCSNAME_LEN] = 0;
        if (!user.iocharset[0] || !strcmp(user.iocharset, "default")) {
                iocharset = load_nls_default();
-               NCP_CLR_FLAG(server, NCP_FLAG_UTF8);
+               utf8 = 0;
        } else if (!strcmp(user.iocharset, "utf8")) {
                iocharset = load_nls_default();
-               NCP_SET_FLAG(server, NCP_FLAG_UTF8);
+               utf8 = 1;
        } else {
                iocharset = load_nls(user.iocharset);
                if (!iocharset) {
                        unload_nls(codepage);
                        return -EBADRQC;
                }
-               NCP_CLR_FLAG(server, NCP_FLAG_UTF8);
+               utf8 = 0;
        }
 
-       oldset_cp = server->nls_vol;
-       server->nls_vol = codepage;
-       oldset_io = server->nls_io;
-       server->nls_io = iocharset;
-
+       mutex_lock(&server->root_setup_lock);
+       if (server->root_setuped) {
+               oldset_cp = codepage;
+               oldset_io = iocharset;
+               err = -EBUSY;
+       } else {
+               if (utf8)
+                       NCP_SET_FLAG(server, NCP_FLAG_UTF8);
+               else
+                       NCP_CLR_FLAG(server, NCP_FLAG_UTF8);
+               oldset_cp = server->nls_vol;
+               server->nls_vol = codepage;
+               oldset_io = server->nls_io;
+               server->nls_io = iocharset;
+               err = 0;
+       }
+       mutex_unlock(&server->root_setup_lock);
        unload_nls(oldset_cp);
        unload_nls(oldset_io);
 
-       return 0;
+       return err;
 }
 
 static int
@@ -237,6 +231,7 @@ ncp_get_charsets(struct ncp_server* server, struct ncp_nls_ioctl __user *arg)
        int len;
 
        memset(&user, 0, sizeof(user));
+       mutex_lock(&server->root_setup_lock);
        if (server->nls_vol && server->nls_vol->charset) {
                len = strlen(server->nls_vol->charset);
                if (len > NCP_IOCSNAME_LEN)
@@ -254,6 +249,7 @@ ncp_get_charsets(struct ncp_server* server, struct ncp_nls_ioctl __user *arg)
                strncpy(user.iocharset, server->nls_io->charset, len);
                user.iocharset[len] = 0;
        }
+       mutex_unlock(&server->root_setup_lock);
 
        if (copy_to_user(arg, &user, sizeof(user)))
                return -EFAULT;
@@ -261,25 +257,19 @@ ncp_get_charsets(struct ncp_server* server, struct ncp_nls_ioctl __user *arg)
 }
 #endif /* CONFIG_NCPFS_NLS */
 
-static long __ncp_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+static long __ncp_ioctl(struct inode *inode, unsigned int cmd, unsigned long arg)
 {
-       struct inode *inode = filp->f_dentry->d_inode;
        struct ncp_server *server = NCP_SERVER(inode);
        int result;
        struct ncp_ioctl_request request;
        char* bouncebuffer;
        void __user *argp = (void __user *)arg;
-       uid_t uid = current_uid();
 
        switch (cmd) {
 #ifdef CONFIG_COMPAT
        case NCP_IOC_NCPREQUEST_32:
 #endif
        case NCP_IOC_NCPREQUEST:
-               if (file_permission(filp, MAY_WRITE) != 0
-                   && uid != server->m.mounted_uid)
-                       return -EACCES;
-
 #ifdef CONFIG_COMPAT
                if (cmd == NCP_IOC_NCPREQUEST_32) {
                        struct compat_ncp_ioctl_request request32;
@@ -314,7 +304,7 @@ static long __ncp_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                server->current_size = request.size;
                memcpy(server->packet, bouncebuffer, request.size);
 
-               result = ncp_request2(server, request.function, 
+               result = ncp_request2(server, request.function,
                        bouncebuffer, NCP_PACKET_SIZE_INTERNAL);
                if (result < 0)
                        result = -EIO;
@@ -331,69 +321,69 @@ static long __ncp_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 
        case NCP_IOC_CONN_LOGGED_IN:
 
-               if (!capable(CAP_SYS_ADMIN))
-                       return -EACCES;
                if (!(server->m.int_flags & NCP_IMOUNT_LOGGEDIN_POSSIBLE))
                        return -EINVAL;
+               mutex_lock(&server->root_setup_lock);
                if (server->root_setuped)
-                       return -EBUSY;
-               server->root_setuped = 1;
-               return ncp_conn_logged_in(inode->i_sb);
+                       result = -EBUSY;
+               else {
+                       result = ncp_conn_logged_in(inode->i_sb);
+                       if (result == 0)
+                               server->root_setuped = 1;
+               }
+               mutex_unlock(&server->root_setup_lock);
+               return result;
 
        case NCP_IOC_GET_FS_INFO:
-               return ncp_get_fs_info(server, filp, argp);
+               return ncp_get_fs_info(server, inode, argp);
 
        case NCP_IOC_GET_FS_INFO_V2:
-               return ncp_get_fs_info_v2(server, filp, argp);
+               return ncp_get_fs_info_v2(server, inode, argp);
 
 #ifdef CONFIG_COMPAT
        case NCP_IOC_GET_FS_INFO_V2_32:
-               return ncp_get_compat_fs_info_v2(server, filp, argp);
+               return ncp_get_compat_fs_info_v2(server, inode, argp);
 #endif
        /* we have too many combinations of CONFIG_COMPAT,
         * CONFIG_64BIT and CONFIG_UID16, so just handle
         * any of the possible ioctls */
        case NCP_IOC_GETMOUNTUID16:
-       case NCP_IOC_GETMOUNTUID32:
-       case NCP_IOC_GETMOUNTUID64:
-               if (file_permission(filp, MAY_READ) != 0
-                       && uid != server->m.mounted_uid)
-                       return -EACCES;
-
-               if (cmd == NCP_IOC_GETMOUNTUID16) {
+               {
                        u16 uid;
+
                        SET_UID(uid, server->m.mounted_uid);
                        if (put_user(uid, (u16 __user *)argp))
                                return -EFAULT;
-               } else if (cmd == NCP_IOC_GETMOUNTUID32) {
-                       if (put_user(server->m.mounted_uid,
-                                               (u32 __user *)argp))
-                               return -EFAULT;
-               } else {
-                       if (put_user(server->m.mounted_uid,
-                                               (u64 __user *)argp))
-                               return -EFAULT;
+                       return 0;
                }
+       case NCP_IOC_GETMOUNTUID32:
+               if (put_user(server->m.mounted_uid,
+                            (u32 __user *)argp))
+                       return -EFAULT;
+               return 0;
+       case NCP_IOC_GETMOUNTUID64:
+               if (put_user(server->m.mounted_uid,
+                            (u64 __user *)argp))
+                       return -EFAULT;
                return 0;
 
        case NCP_IOC_GETROOT:
                {
                        struct ncp_setroot_ioctl sr;
 
-                       if (file_permission(filp, MAY_READ) != 0
-                           && uid != server->m.mounted_uid)
-                               return -EACCES;
-
+                       result = -EACCES;
+                       mutex_lock(&server->root_setup_lock);
                        if (server->m.mounted_vol[0]) {
                                struct dentry* dentry = inode->i_sb->s_root;
 
                                if (dentry) {
                                        struct inode* s_inode = dentry->d_inode;
-                               
+
                                        if (s_inode) {
                                                sr.volNumber = NCP_FINFO(s_inode)->volNumber;
                                                sr.dirEntNum = NCP_FINFO(s_inode)->dirEntNum;
                                                sr.namespace = server->name_space[sr.volNumber];
+                                               result = 0;
                                        } else
                                                DPRINTK("ncpfs: s_root->d_inode==NULL\n");
                                } else
@@ -402,10 +392,12 @@ static long __ncp_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                                sr.volNumber = -1;
                                sr.namespace = 0;
                                sr.dirEntNum = 0;
+                               result = 0;
                        }
-                       if (copy_to_user(argp, &sr, sizeof(sr)))
-                               return -EFAULT;
-                       return 0;
+                       mutex_unlock(&server->root_setup_lock);
+                       if (!result && copy_to_user(argp, &sr, sizeof(sr)))
+                               result = -EFAULT;
+                       return result;
                }
 
        case NCP_IOC_SETROOT:
@@ -416,103 +408,114 @@ static long __ncp_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                        __le32 dosde;
                        struct dentry* dentry;
 
-                       if (!capable(CAP_SYS_ADMIN))
-                       {
-                               return -EACCES;
-                       }
-                       if (server->root_setuped) return -EBUSY;
                        if (copy_from_user(&sr, argp, sizeof(sr)))
                                return -EFAULT;
-                       if (sr.volNumber < 0) {
-                               server->m.mounted_vol[0] = 0;
-                               vnum = NCP_NUMBER_OF_VOLUMES;
-                               de = 0;
-                               dosde = 0;
-                       } else if (sr.volNumber >= NCP_NUMBER_OF_VOLUMES) {
-                               return -EINVAL;
-                       } else if (ncp_mount_subdir(server, sr.volNumber,
-                                               sr.namespace, sr.dirEntNum,
-                                               &vnum, &de, &dosde)) {
-                               return -ENOENT;
-                       }
-                       
-                       dentry = inode->i_sb->s_root;
-                       server->root_setuped = 1;
-                       if (dentry) {
-                               struct inode* s_inode = dentry->d_inode;
-                               
-                               if (s_inode) {
-                                       NCP_FINFO(s_inode)->volNumber = vnum;
-                                       NCP_FINFO(s_inode)->dirEntNum = de;
-                                       NCP_FINFO(s_inode)->DosDirNum = dosde;
+                       mutex_lock(&server->root_setup_lock);
+                       if (server->root_setuped)
+                               result = -EBUSY;
+                       else {
+                               if (sr.volNumber < 0) {
+                                       server->m.mounted_vol[0] = 0;
+                                       vnum = NCP_NUMBER_OF_VOLUMES;
+                                       de = 0;
+                                       dosde = 0;
+                                       result = 0;
+                               } else if (sr.volNumber >= NCP_NUMBER_OF_VOLUMES) {
+                                       result = -EINVAL;
+                               } else if (ncp_mount_subdir(server, sr.volNumber,
+                                                       sr.namespace, sr.dirEntNum,
+                                                       &vnum, &de, &dosde)) {
+                                       result = -ENOENT;
                                } else
-                                       DPRINTK("ncpfs: s_root->d_inode==NULL\n");
-                       } else
-                               DPRINTK("ncpfs: s_root==NULL\n");
+                                       result = 0;
+
+                               if (result == 0) {
+                                       dentry = inode->i_sb->s_root;
+                                       if (dentry) {
+                                               struct inode* s_inode = dentry->d_inode;
+
+                                               if (s_inode) {
+                                                       NCP_FINFO(s_inode)->volNumber = vnum;
+                                                       NCP_FINFO(s_inode)->dirEntNum = de;
+                                                       NCP_FINFO(s_inode)->DosDirNum = dosde;
+                                                       server->root_setuped = 1;
+                                               } else {
+                                                       DPRINTK("ncpfs: s_root->d_inode==NULL\n");
+                                                       result = -EIO;
+                                               }
+                                       } else {
+                                               DPRINTK("ncpfs: s_root==NULL\n");
+                                               result = -EIO;
+                                       }
+                               }
+                               result = 0;
+                       }
+                       mutex_unlock(&server->root_setup_lock);
 
-                       return 0;
+                       return result;
                }
 
-#ifdef CONFIG_NCPFS_PACKET_SIGNING     
+#ifdef CONFIG_NCPFS_PACKET_SIGNING
        case NCP_IOC_SIGN_INIT:
-               if (file_permission(filp, MAY_WRITE) != 0
-                   && uid != server->m.mounted_uid)
-                       return -EACCES;
-
-               if (argp) {
-                       if (server->sign_wanted)
-                       {
-                               struct ncp_sign_init sign;
+               {
+                       struct ncp_sign_init sign;
 
+                       if (argp)
                                if (copy_from_user(&sign, argp, sizeof(sign)))
                                        return -EFAULT;
-                               memcpy(server->sign_root,sign.sign_root,8);
-                               memcpy(server->sign_last,sign.sign_last,16);
-                               server->sign_active = 1;
+                       ncp_lock_server(server);
+                       mutex_lock(&server->rcv.creq_mutex);
+                       if (argp) {
+                               if (server->sign_wanted) {
+                                       memcpy(server->sign_root,sign.sign_root,8);
+                                       memcpy(server->sign_last,sign.sign_last,16);
+                                       server->sign_active = 1;
+                               }
+                               /* ignore when signatures not wanted */
+                       } else {
+                               server->sign_active = 0;
                        }
-                       /* ignore when signatures not wanted */
-               } else {
-                       server->sign_active = 0;
+                       mutex_unlock(&server->rcv.creq_mutex);
+                       ncp_unlock_server(server);
+                       return 0;
                }
-               return 0;               
-               
+
         case NCP_IOC_SIGN_WANTED:
-               if (file_permission(filp, MAY_READ) != 0
-                   && uid != server->m.mounted_uid)
-                       return -EACCES;
-               
-                if (put_user(server->sign_wanted, (int __user *)argp))
-                       return -EFAULT;
-                return 0;
+               {
+                       int state;
+
+                       ncp_lock_server(server);
+                       state = server->sign_wanted;
+                       ncp_unlock_server(server);
+                       if (put_user(state, (int __user *)argp))
+                               return -EFAULT;
+                       return 0;
+               }
 
        case NCP_IOC_SET_SIGN_WANTED:
                {
                        int newstate;
 
-                       if (file_permission(filp, MAY_WRITE) != 0
-                           && uid != server->m.mounted_uid)
-                               return -EACCES;
-
                        /* get only low 8 bits... */
                        if (get_user(newstate, (unsigned char __user *)argp))
                                return -EFAULT;
+                       result = 0;
+                       ncp_lock_server(server);
                        if (server->sign_active) {
                                /* cannot turn signatures OFF when active */
-                               if (!newstate) return -EINVAL;
+                               if (!newstate)
+                                       result = -EINVAL;
                        } else {
                                server->sign_wanted = newstate != 0;
                        }
-                       return 0;
+                       ncp_unlock_server(server);
+                       return result;
                }
 
 #endif /* CONFIG_NCPFS_PACKET_SIGNING */
 
 #ifdef CONFIG_NCPFS_IOCTL_LOCKING
        case NCP_IOC_LOCKUNLOCK:
-               if (file_permission(filp, MAY_WRITE) != 0
-                   && uid != server->m.mounted_uid)
-                       return -EACCES;
-
                {
                        struct ncp_lock_ioctl    rqdata;
 
@@ -541,16 +544,13 @@ static long __ncp_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                        {
                                return result;
                        }
-                       result = -EIO;
-                       if (!ncp_conn_valid(server))
-                               goto outrel;
                        result = -EISDIR;
                        if (!S_ISREG(inode->i_mode))
                                goto outrel;
                        if (rqdata.cmd == NCP_LOCK_CLEAR)
                        {
                                result = ncp_ClearPhysicalRecord(NCP_SERVER(inode),
-                                                       NCP_FINFO(inode)->file_handle, 
+                                                       NCP_FINFO(inode)->file_handle,
                                                        rqdata.offset,
                                                        rqdata.length);
                                if (result > 0) result = 0;     /* no such lock */
@@ -573,7 +573,7 @@ static long __ncp_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                                                        rqdata.timeout);
                                if (result > 0) result = -EAGAIN;
                        }
-outrel:                        
+outrel:
                        ncp_inode_close(inode);
                        return result;
                }
@@ -581,60 +581,62 @@ outrel:
 
 #ifdef CONFIG_COMPAT
        case NCP_IOC_GETOBJECTNAME_32:
-               if (uid != server->m.mounted_uid)
-                       return -EACCES;
                {
                        struct compat_ncp_objectname_ioctl user;
                        size_t outl;
 
                        if (copy_from_user(&user, argp, sizeof(user)))
                                return -EFAULT;
+                       down_read(&server->auth_rwsem);
                        user.auth_type = server->auth.auth_type;
                        outl = user.object_name_len;
                        user.object_name_len = server->auth.object_name_len;
                        if (outl > user.object_name_len)
                                outl = user.object_name_len;
+                       result = 0;
                        if (outl) {
                                if (copy_to_user(compat_ptr(user.object_name),
                                                 server->auth.object_name,
-                                                outl)) return -EFAULT;
+                                                outl))
+                                       result = -EFAULT;
                        }
-                       if (copy_to_user(argp, &user, sizeof(user)))
-                               return -EFAULT;
-                       return 0;
+                       up_read(&server->auth_rwsem);
+                       if (!result && copy_to_user(argp, &user, sizeof(user)))
+                               result = -EFAULT;
+                       return result;
                }
 #endif
 
        case NCP_IOC_GETOBJECTNAME:
-               if (uid != server->m.mounted_uid)
-                       return -EACCES;
                {
                        struct ncp_objectname_ioctl user;
                        size_t outl;
 
                        if (copy_from_user(&user, argp, sizeof(user)))
                                return -EFAULT;
+                       down_read(&server->auth_rwsem);
                        user.auth_type = server->auth.auth_type;
                        outl = user.object_name_len;
                        user.object_name_len = server->auth.object_name_len;
                        if (outl > user.object_name_len)
                                outl = user.object_name_len;
+                       result = 0;
                        if (outl) {
                                if (copy_to_user(user.object_name,
                                                 server->auth.object_name,
-                                                outl)) return -EFAULT;
+                                                outl))
+                                       result = -EFAULT;
                        }
-                       if (copy_to_user(argp, &user, sizeof(user)))
-                               return -EFAULT;
-                       return 0;
+                       up_read(&server->auth_rwsem);
+                       if (!result && copy_to_user(argp, &user, sizeof(user)))
+                               result = -EFAULT;
+                       return result;
                }
 
 #ifdef CONFIG_COMPAT
        case NCP_IOC_SETOBJECTNAME_32:
 #endif
        case NCP_IOC_SETOBJECTNAME:
-               if (uid != server->m.mounted_uid)
-                       return -EACCES;
                {
                        struct ncp_objectname_ioctl user;
                        void* newname;
@@ -666,9 +668,7 @@ outrel:
                        } else {
                                newname = NULL;
                        }
-                       /* enter critical section */
-                       /* maybe that kfree can sleep so do that this way */
-                       /* it is at least more SMP friendly (in future...) */
+                       down_write(&server->auth_rwsem);
                        oldname = server->auth.object_name;
                        oldnamelen = server->auth.object_name_len;
                        oldprivate = server->priv.data;
@@ -678,7 +678,7 @@ outrel:
                        server->auth.object_name = newname;
                        server->priv.len = 0;
                        server->priv.data = NULL;
-                       /* leave critical section */
+                       up_write(&server->auth_rwsem);
                        kfree(oldprivate);
                        kfree(oldname);
                        return 0;
@@ -688,8 +688,6 @@ outrel:
        case NCP_IOC_GETPRIVATEDATA_32:
 #endif
        case NCP_IOC_GETPRIVATEDATA:
-               if (uid != server->m.mounted_uid)
-                       return -EACCES;
                {
                        struct ncp_privatedata_ioctl user;
                        size_t outl;
@@ -706,14 +704,20 @@ outrel:
                        if (copy_from_user(&user, argp, sizeof(user)))
                                return -EFAULT;
 
+                       down_read(&server->auth_rwsem);
                        outl = user.len;
                        user.len = server->priv.len;
                        if (outl > user.len) outl = user.len;
+                       result = 0;
                        if (outl) {
                                if (copy_to_user(user.data,
                                                 server->priv.data,
-                                                outl)) return -EFAULT;
+                                                outl))
+                                       result = -EFAULT;
                        }
+                       up_read(&server->auth_rwsem);
+                       if (result)
+                               return result;
 #ifdef CONFIG_COMPAT
                        if (cmd == NCP_IOC_GETPRIVATEDATA_32) {
                                struct compat_ncp_privatedata_ioctl user32;
@@ -733,8 +737,6 @@ outrel:
        case NCP_IOC_SETPRIVATEDATA_32:
 #endif
        case NCP_IOC_SETPRIVATEDATA:
-               if (uid != server->m.mounted_uid)
-                       return -EACCES;
                {
                        struct ncp_privatedata_ioctl user;
                        void* new;
@@ -762,12 +764,12 @@ outrel:
                        } else {
                                new = NULL;
                        }
-                       /* enter critical section */
+                       down_write(&server->auth_rwsem);
                        old = server->priv.data;
                        oldlen = server->priv.len;
                        server->priv.len = user.len;
                        server->priv.data = new;
-                       /* leave critical section */
+                       up_write(&server->auth_rwsem);
                        kfree(old);
                        return 0;
                }
@@ -775,17 +777,13 @@ outrel:
 #ifdef CONFIG_NCPFS_NLS
        case NCP_IOC_SETCHARSETS:
                return ncp_set_charsets(server, argp);
-               
+
        case NCP_IOC_GETCHARSETS:
                return ncp_get_charsets(server, argp);
 
 #endif /* CONFIG_NCPFS_NLS */
 
        case NCP_IOC_SETDENTRYTTL:
-               if (file_permission(filp, MAY_WRITE) != 0 &&
-                   uid != server->m.mounted_uid)
-                       return -EACCES;
-
                {
                        u_int32_t user;
 
@@ -795,13 +793,13 @@ outrel:
                        if (user > 20000)
                                return -EINVAL;
                        user = (user * HZ) / 1000;
-                       server->dentry_ttl = user;
+                       atomic_set(&server->dentry_ttl, user);
                        return 0;
                }
-               
+
        case NCP_IOC_GETDENTRYTTL:
                {
-                       u_int32_t user = (server->dentry_ttl * 1000) / HZ;
+                       u_int32_t user = (atomic_read(&server->dentry_ttl) * 1000) / HZ;
                        if (copy_to_user(argp, &user, sizeof(user)))
                                return -EFAULT;
                        return 0;
@@ -811,59 +809,103 @@ outrel:
        return -EINVAL;
 }
 
-static int ncp_ioctl_need_write(unsigned int cmd)
+long ncp_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
+       struct inode *inode = filp->f_dentry->d_inode;
+       struct ncp_server *server = NCP_SERVER(inode);
+       uid_t uid = current_uid();
+       int need_drop_write = 0;
+       long ret;
+
        switch (cmd) {
-       case NCP_IOC_GET_FS_INFO:
-       case NCP_IOC_GET_FS_INFO_V2:
-       case NCP_IOC_NCPREQUEST:
-       case NCP_IOC_SETDENTRYTTL:
-       case NCP_IOC_SIGN_INIT:
-       case NCP_IOC_LOCKUNLOCK:
-       case NCP_IOC_SET_SIGN_WANTED:
-               return 1;
-       case NCP_IOC_GETOBJECTNAME:
-       case NCP_IOC_SETOBJECTNAME:
-       case NCP_IOC_GETPRIVATEDATA:
-       case NCP_IOC_SETPRIVATEDATA:
        case NCP_IOC_SETCHARSETS:
-       case NCP_IOC_GETCHARSETS:
        case NCP_IOC_CONN_LOGGED_IN:
-       case NCP_IOC_GETDENTRYTTL:
-       case NCP_IOC_GETMOUNTUID2:
-       case NCP_IOC_SIGN_WANTED:
-       case NCP_IOC_GETROOT:
        case NCP_IOC_SETROOT:
-               return 0;
-       default:
-               /* unknown IOCTL command, assume write */
-               return 1;
+               if (!capable(CAP_SYS_ADMIN)) {
+                       ret = -EACCES;
+                       goto out;
+               }
+               break;
        }
-}
-
-long ncp_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
-{
-       long ret;
-
-       lock_kernel();
-       if (ncp_ioctl_need_write(cmd)) {
+       if (server->m.mounted_uid != uid) {
+               switch (cmd) {
                /*
-                * inside the ioctl(), any failures which
-                * are because of file_permission() are
-                * -EACCESS, so it seems consistent to keep
-                *  that here.
+                * Only mount owner can issue these ioctls.  Information
+                * necessary to authenticate to other NDS servers are
+                * stored here.
                 */
-               if (mnt_want_write(filp->f_path.mnt)) {
+               case NCP_IOC_GETOBJECTNAME:
+               case NCP_IOC_SETOBJECTNAME:
+               case NCP_IOC_GETPRIVATEDATA:
+               case NCP_IOC_SETPRIVATEDATA:
+#ifdef CONFIG_COMPAT
+               case NCP_IOC_GETOBJECTNAME_32:
+               case NCP_IOC_SETOBJECTNAME_32:
+               case NCP_IOC_GETPRIVATEDATA_32:
+               case NCP_IOC_SETPRIVATEDATA_32:
+#endif
                        ret = -EACCES;
                        goto out;
+               /*
+                * These require write access on the inode if user id
+                * does not match.  Note that they do not write to the
+                * file...  But old code did mnt_want_write, so I keep
+                * it as is.  Of course not for mountpoint owner, as
+                * that breaks read-only mounts altogether as ncpmount
+                * needs working NCP_IOC_NCPREQUEST and
+                * NCP_IOC_GET_FS_INFO.  Some of these codes (setdentryttl,
+                * signinit, setsignwanted) should be probably restricted
+                * to owner only, or even more to CAP_SYS_ADMIN).
+                */
+               case NCP_IOC_GET_FS_INFO:
+               case NCP_IOC_GET_FS_INFO_V2:
+               case NCP_IOC_NCPREQUEST:
+               case NCP_IOC_SETDENTRYTTL:
+               case NCP_IOC_SIGN_INIT:
+               case NCP_IOC_LOCKUNLOCK:
+               case NCP_IOC_SET_SIGN_WANTED:
+#ifdef CONFIG_COMPAT
+               case NCP_IOC_GET_FS_INFO_V2_32:
+               case NCP_IOC_NCPREQUEST_32:
+#endif
+                       ret = mnt_want_write_file(filp);
+                       if (ret)
+                               goto out;
+                       need_drop_write = 1;
+                       ret = inode_permission(inode, MAY_WRITE);
+                       if (ret)
+                               goto outDropWrite;
+                       break;
+               /*
+                * Read access required.
+                */
+               case NCP_IOC_GETMOUNTUID16:
+               case NCP_IOC_GETMOUNTUID32:
+               case NCP_IOC_GETMOUNTUID64:
+               case NCP_IOC_GETROOT:
+               case NCP_IOC_SIGN_WANTED:
+                       ret = inode_permission(inode, MAY_READ);
+                       if (ret)
+                               goto out;
+                       break;
+               /*
+                * Anybody can read these.
+                */
+               case NCP_IOC_GETCHARSETS:
+               case NCP_IOC_GETDENTRYTTL:
+               default:
+               /* Three codes below are protected by CAP_SYS_ADMIN above. */
+               case NCP_IOC_SETCHARSETS:
+               case NCP_IOC_CONN_LOGGED_IN:
+               case NCP_IOC_SETROOT:
+                       break;
                }
        }
-       ret = __ncp_ioctl(filp, cmd, arg);
-       if (ncp_ioctl_need_write(cmd))
+       ret = __ncp_ioctl(inode, cmd, arg);
+outDropWrite:
+       if (need_drop_write)
                mnt_drop_write(filp->f_path.mnt);
-
 out:
-       unlock_kernel();
        return ret;
 }
 
@@ -872,10 +914,8 @@ long ncp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
        long ret;
 
-       lock_kernel();
        arg = (unsigned long) compat_ptr(arg);
        ret = ncp_ioctl(file, cmd, arg);
-       unlock_kernel();
        return ret;
 }
 #endif