diff options
Diffstat (limited to 'static/netbsd/man4/fss.4')
| -rw-r--r-- | static/netbsd/man4/fss.4 | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/static/netbsd/man4/fss.4 b/static/netbsd/man4/fss.4 new file mode 100644 index 00000000..8274dfbb --- /dev/null +++ b/static/netbsd/man4/fss.4 @@ -0,0 +1,158 @@ +.\" $NetBSD: fss.4,v 1.15 2011/02/24 09:38:57 hannken Exp $ */ +.\" +.\" +.\" Copyright (c) 2003 The NetBSD Foundation, Inc. +.\" All rights reserved. +.\" +.\" This code is derived from software contributed to The NetBSD Foundation +.\" by Juergen Hannken-Illjes. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS +.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED +.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR +.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS +.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR +.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF +.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN +.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) +.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +.\" POSSIBILITY OF SUCH DAMAGE. +.\" +.Dd February 24, 2011 +.Dt FSS 4 +.Os +.Sh NAME +.Nm fss +.Nd file system snapshot device +.Sh SYNOPSIS +.Cd "pseudo-device fss 4" +.Sh DESCRIPTION +The +.Nm +driver provides a read-only interface to the snapshot of a currently +mounted file system. +Reading from a +.Nm +device gives the view of the file system when the snapshot was taken. +It can be configured via +.Xr ioctl 2 . +.Sh IOCTLS +The +.Xr ioctl 2 +command codes below are defined in +.In sys/dev/fssvar.h . +.Pp +The (third) argument to +.Xr ioctl 2 +should be a pointer to the type indicated. +.Bl -tag -width 8n +.It Dv FSSIOCSET(struct fss_set) +Configures a +.Nm +device. +.Bd -literal -offset indent +struct fss_set { + char *fss_mount; + char *fss_bstore; + blksize_t fss_csize; + int fss_flags; +}; +.Ed +.Pp +The struct element +.Va fss_mount +is the mount point of the file system. +The struct element +.Va fss_bstore +is either a regular file or a raw disk device where data overwritten on +the file system will be saved. +The struct element +.Va fss_csize +is the preferred size of this data. +The struct element +.Va fss_flags +is the initial set of flags. +.It Dv FSSIOCGET(struct fss_get) +Gets the status of a +.Nm +device. +.Bd -literal -offset indent +struct fss_get { + char fsg_mount[MNAMELEN]; + struct timeval fsg_time; + blksize_t fsg_csize; + blkcnt_t fsg_mount_size; + blkcnt_t fsg_bs_size; +}; +.Ed +The struct element +.Va fsg_mount +is the mount point of the file system. +The struct element +.Va fsg_time +is the time this snapshot was taken. +The struct element +.Va fsg_csize +is the current size of data clusters. +The struct element +.Va fsg_mount_size +is the number of clusters of the file system. +The struct element +.Va fsg_bs_size +is the number of clusters written to the backing store. +.It Dv FSSIOCCLR +Unconfigures a +.Nm +device. +.It Dv FSSIOFSET(int) +Sets the flags of a +.Nm +device. +Possible flags are: +.Bl -tag -width Dv +.It Dv FSS_UNCONFIG_ON_CLOSE +Unconfigure the +.Nm +device on the last close. +.It Dv FSS_UNLINK_ON_CREATE +Unlink the backing file before the +.Nm +device is created. +.El +.It Dv FSSIOFGET(int) +Gets the flags of a +.Nm +device. +.El +.Sh KERNEL THREADS +For each active snapshot device there is a kernel thread +that handles the backing store. +This thread is named +.Va fssN +where +.Va N +is the device minor number. +.Sh FILES +.Bl -tag -width /dev/rfss? -compact +.It Pa /dev/rfss? +.It Pa /dev/fss? +.El +.Sh SEE ALSO +.Xr fssconfig 8 , +.Xr mount 8 , +.Xr umount 8 +.Sh HISTORY +The +.Nm +device appeared in +.Nx 2.0 . |