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authorjmmv <jmmv@NetBSD.org>2006-12-19 14:50:49 +0000
committerjmmv <jmmv@NetBSD.org>2006-12-19 14:50:49 +0000
commit320a6bcfea661096719fcc2dfe3afbeefca35331 (patch)
tree22f4948dfe71b9ef8337668ac7ffa5fe020e4ead /sbin/mount_tmpfs
parent41d24e831c7f6afd7c3fc38ab6b601caf09a4932 (diff)
Note that meta data is stored in non-pageable memory and the problems this
may carry. Suggested by Greg Troxel in private mail.
Diffstat (limited to 'sbin/mount_tmpfs')
-rw-r--r--sbin/mount_tmpfs/mount_tmpfs.818
1 files changed, 16 insertions, 2 deletions
diff --git a/sbin/mount_tmpfs/mount_tmpfs.8 b/sbin/mount_tmpfs/mount_tmpfs.8
index 3a10b7d9445..da819be6188 100644
--- a/sbin/mount_tmpfs/mount_tmpfs.8
+++ b/sbin/mount_tmpfs/mount_tmpfs.8
@@ -1,4 +1,4 @@
-.\" $NetBSD: mount_tmpfs.8,v 1.9 2006/11/11 19:01:30 jmmv Exp $
+.\" $NetBSD: mount_tmpfs.8,v 1.10 2006/12/19 14:50:49 jmmv Exp $
.\"
.\" Copyright (c) 2005, 2006 The NetBSD Foundation, Inc.
.\" All rights reserved.
@@ -35,7 +35,7 @@
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
.\"
-.Dd November 11, 2006
+.Dd December 19, 2006
.Dt MOUNT_TMPFS 8
.Os
.Sh NAME
@@ -72,6 +72,9 @@ Specifies the mode (in octal notation) of the root inode of the file system.
Defaults to the mount point's mode.
.It Fl n Ar nodes
Specifies the maximum number of nodes available to the file system.
+If not specified, the file system chooses a reasonable maximum given its
+size at mount time, which can be limited with
+.Fl s .
.It Fl o Ar options
Options are specified with a
.Fl o
@@ -130,3 +133,14 @@ The
.Nm
utility first appeared in
.Nx 4.0 .
+.Sh BUGS
+File system meta-data is not pageable.
+If there is not enough main memory to hold this information, the system may
+become unstable or very unresponsive because it will not be able to allocate
+required memory.
+A malicious user could trigger this condition if he could create tons of
+files inside a size-unbounded tmpfs file system.
+Limiting the number of nodes per file system
+.Fl ( n )
+will prevent this; the default value for this setting is also often adjusted
+to an adequate value to resolve this.