17a2de9a4SMatthew Dillon.\" $NetBSD: mount_tmpfs.8,v 1.14 2008/04/30 13:10:53 martin Exp $ 27a2de9a4SMatthew Dillon.\" 37a2de9a4SMatthew Dillon.\" Copyright (c) 2005, 2006 The NetBSD Foundation, Inc. 47a2de9a4SMatthew Dillon.\" All rights reserved. 57a2de9a4SMatthew Dillon.\" 67a2de9a4SMatthew Dillon.\" This code is derived from software contributed to The NetBSD Foundation 77a2de9a4SMatthew Dillon.\" by Julio M. Merino Vidal, developed as part of Google's Summer of Code 87a2de9a4SMatthew Dillon.\" 2005 program. 97a2de9a4SMatthew Dillon.\" 107a2de9a4SMatthew Dillon.\" Redistribution and use in source and binary forms, with or without 117a2de9a4SMatthew Dillon.\" modification, are permitted provided that the following conditions 127a2de9a4SMatthew Dillon.\" are met: 137a2de9a4SMatthew Dillon.\" 1. Redistributions of source code must retain the above copyright 147a2de9a4SMatthew Dillon.\" notice, this list of conditions and the following disclaimer. 157a2de9a4SMatthew Dillon.\" 2. Redistributions in binary form must reproduce the above copyright 167a2de9a4SMatthew Dillon.\" notice, this list of conditions and the following disclaimer in the 177a2de9a4SMatthew Dillon.\" documentation and/or other materials provided with the distribution. 187a2de9a4SMatthew Dillon.\" 197a2de9a4SMatthew Dillon.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 207a2de9a4SMatthew Dillon.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 217a2de9a4SMatthew Dillon.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 227a2de9a4SMatthew Dillon.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 237a2de9a4SMatthew Dillon.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 247a2de9a4SMatthew Dillon.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 257a2de9a4SMatthew Dillon.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 267a2de9a4SMatthew Dillon.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 277a2de9a4SMatthew Dillon.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 287a2de9a4SMatthew Dillon.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 297a2de9a4SMatthew Dillon.\" POSSIBILITY OF SUCH DAMAGE. 307a2de9a4SMatthew Dillon.\" 31b8170153SSascha Wildner.Dd September 18, 2010 327a2de9a4SMatthew Dillon.Dt MOUNT_TMPFS 8 337a2de9a4SMatthew Dillon.Os 347a2de9a4SMatthew Dillon.Sh NAME 357a2de9a4SMatthew Dillon.Nm mount_tmpfs 367a2de9a4SMatthew Dillon.Nd mount an efficient memory file system 377a2de9a4SMatthew Dillon.Sh SYNOPSIS 387a2de9a4SMatthew Dillon.Nm 39b8170153SSascha Wildner.Op Fl C 40817a2fd9SMatthew Dillon.Op Fl f Ar maxfilesize 417a2de9a4SMatthew Dillon.Op Fl g Ar group 427a2de9a4SMatthew Dillon.Op Fl m Ar mode 437a2de9a4SMatthew Dillon.Op Fl n Ar nodes 447a2de9a4SMatthew Dillon.Op Fl o Ar options 457a2de9a4SMatthew Dillon.Op Fl s Ar size 467a2de9a4SMatthew Dillon.Op Fl u Ar user 477a2de9a4SMatthew Dillon.Ar tmpfs 487a2de9a4SMatthew Dillon.Ar mount_point 497a2de9a4SMatthew Dillon.Sh DESCRIPTION 507a2de9a4SMatthew DillonThe 517a2de9a4SMatthew Dillon.Nm 527a2de9a4SMatthew Dilloncommand attaches an instance of the efficient memory file system to the 537a2de9a4SMatthew Dillonglobal file system namespace. 547a2de9a4SMatthew DillonThe 557a2de9a4SMatthew Dillon.Ar tmpfs 567a2de9a4SMatthew Dillonparameter only exists for compatibility with the other mount commands and 577a2de9a4SMatthew Dillonis ignored. 587a2de9a4SMatthew DillonThe directory specified by 597a2de9a4SMatthew Dillon.Ar mount_point 607a2de9a4SMatthew Dillonis converted to an absolute path before use and its attributes (owner, 61*566ca746SSascha Wildnergroup and mode) are inherited unless explicitly overridden by the options 627a2de9a4SMatthew Dillondescribed below. 637a2de9a4SMatthew Dillon.Pp 647a2de9a4SMatthew DillonThe following options are supported: 657a2de9a4SMatthew Dillon.Bl -tag -width XoXoptions 66b8170153SSascha Wildner.It Fl C 67b8170153SSascha WildnerTells 68b8170153SSascha Wildner.Nm 69b8170153SSascha Wildnerto copy the underlying file system into the tmpfs mount being created 70b8170153SSascha Wildnerover it. 71817a2fd9SMatthew Dillon.It Fl f Ar maxfilesize 72817a2fd9SMatthew DillonSpecifies the maximum file size of the file system. 737a2de9a4SMatthew Dillon.It Fl g Ar group 747a2de9a4SMatthew DillonSpecifies the group name or GID of the root inode of the file system. 757a2de9a4SMatthew DillonDefaults to the mount point's GID. 767a2de9a4SMatthew Dillon.It Fl m Ar mode 777a2de9a4SMatthew DillonSpecifies the mode (in octal notation) of the root inode of the file system. 787a2de9a4SMatthew DillonDefaults to the mount point's mode. 797a2de9a4SMatthew Dillon.It Fl n Ar nodes 807a2de9a4SMatthew DillonSpecifies the maximum number of nodes available to the file system. 817a2de9a4SMatthew DillonIf not specified, the file system chooses a reasonable maximum given its 827a2de9a4SMatthew Dillonsize at mount time, which can be limited with 837a2de9a4SMatthew Dillon.Fl s . 847a2de9a4SMatthew Dillon.It Fl o Ar options 857a2de9a4SMatthew DillonOptions are specified with a 867a2de9a4SMatthew Dillon.Fl o 877a2de9a4SMatthew Dillonflag followed by a comma-separated string of options. 887a2de9a4SMatthew DillonSee the 897a2de9a4SMatthew Dillon.Xr mount 8 90817a2fd9SMatthew Dillonand 91817a2fd9SMatthew Dillon.Xr tmpfs 5 927a2de9a4SMatthew Dillonman page for possible options and their meanings. 937a2de9a4SMatthew Dillon.It Fl s Ar size 94817a2fd9SMatthew DillonSpecifies the total file system size. 957a2de9a4SMatthew DillonIf zero is given (the default), the available amount of memory (including 967a2de9a4SMatthew Dillonmain memory and swap space) will be used. 977a2de9a4SMatthew DillonNote that four megabytes are always reserved for the system and cannot 987a2de9a4SMatthew Dillonbe assigned to the file system. 997a2de9a4SMatthew Dillon.It Fl u Ar user 1007a2de9a4SMatthew DillonSpecifies the user name or UID of the root inode of the file system. 1017a2de9a4SMatthew DillonDefaults to the mount point's UID. 1027a2de9a4SMatthew Dillon.El 1037a2de9a4SMatthew Dillon.Pp 1047a2de9a4SMatthew DillonEvery option that accepts a numerical value as its argument can take a 1057a2de9a4SMatthew Dillontrailing 1067a2de9a4SMatthew Dillon.Sq b 1077a2de9a4SMatthew Dillonto indicate bytes (the default), a trailing 1087a2de9a4SMatthew Dillon.Sq k 1097a2de9a4SMatthew Dillonto indicate kilobytes, a trailing 1107a2de9a4SMatthew Dillon.Sq M 1117a2de9a4SMatthew Dillonto indicate megabytes or a trailing 1127a2de9a4SMatthew Dillon.Sq G 1137a2de9a4SMatthew Dillonto indicate gigabytes. 1147a2de9a4SMatthew DillonNote that both lowercase and uppercase forms of these letters are allowed. 1157a2de9a4SMatthew Dillon.Sh EXAMPLES 1167a2de9a4SMatthew DillonThe following command mounts a tmpfs instance over the 1177a2de9a4SMatthew Dillon.Pa /tmp 1187a2de9a4SMatthew Dillondirectory, inheriting its owner, group and mode settings: 1197a2de9a4SMatthew Dillon.Pp 1207a2de9a4SMatthew Dillon.Ic "mount -t tmpfs tmpfs /tmp" 1217a2de9a4SMatthew Dillon.Pp 1227a2de9a4SMatthew DillonThe following command mounts a tmpfs instance over the 1237a2de9a4SMatthew Dillon.Pa /mnt 1247a2de9a4SMatthew Dillondirectory, setting a 20 megabytes limit in space, owned by the 1257a2de9a4SMatthew Dillon.Sq joe 1267a2de9a4SMatthew Dillonuser and belonging to the 1277a2de9a4SMatthew Dillon.Sq users 1287a2de9a4SMatthew Dillongroup, with a restricted 0700 mode: 1297a2de9a4SMatthew Dillon.Pp 1307a2de9a4SMatthew Dillon.Ic "mount -t tmpfs -o -s20M -o -ujoe -o -gusers -o -m0700 tmpfs /mnt" 1317a2de9a4SMatthew Dillon.Pp 132817a2fd9SMatthew Dillonor 133817a2fd9SMatthew Dillon.Pp 134817a2fd9SMatthew Dillon.Ic "mount -t tmpfs -o size=20M,uid=joe,gid=users,mode=0700 tmpfs /mnt" 1357a2de9a4SMatthew Dillon.Sh SEE ALSO 1367a2de9a4SMatthew Dillon.Xr fstab 5 , 1373cd583efSSascha Wildner.Xr tmpfs 5 , 1383cd583efSSascha Wildner.Xr mount 8 1397a2de9a4SMatthew Dillon.Sh HISTORY 1407a2de9a4SMatthew DillonThe 1417a2de9a4SMatthew Dillon.Nm 1427a2de9a4SMatthew Dillonutility first appeared in 1437a2de9a4SMatthew Dillon.Nx 4.0 . 1447a2de9a4SMatthew Dillon.Sh BUGS 1457a2de9a4SMatthew DillonFile system meta-data is not pageable. 1467a2de9a4SMatthew DillonIf there is not enough main memory to hold this information, the system may 1477a2de9a4SMatthew Dillonbecome unstable or very unresponsive because it will not be able to allocate 1487a2de9a4SMatthew Dillonrequired memory. 1497a2de9a4SMatthew DillonA malicious user could trigger this condition if he could create lots of 1507a2de9a4SMatthew Dillonfiles inside a size-unbounded tmpfs file system. 1517a2de9a4SMatthew DillonLimiting the number of nodes per file system 1527a2de9a4SMatthew Dillon.Pq Fl n 1537a2de9a4SMatthew Dillonwill prevent this; the default value for this setting is also often adjusted 1547a2de9a4SMatthew Dillonto an adequate value to resolve this. 155