'\" t
.\" Title: btrfstune
.\" Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.76.1
.\" Date: 06/20/2015
.\" Manual: Btrfs Manual
.\" Source: Btrfs v3.17
.\" Language: English
.\"
.TH "BTRFSTUNE" "8" "06/20/2015" "Btrfs v3\&.17" "Btrfs Manual"
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.SH "NAME"
btrfstune \- tune various btrfs filesystem parameters
.SH "SYNOPSIS"
.sp
\fBbtrfstune\fR [options] \fI\fR [\fI\fR\&...]
.SH "DESCRIPTION"
.sp
\fBbtrfstune\fR is used to tune various btrfs filesystem parameters,you can enable/disable some extended features for btrfs\&.
.SH "OPTIONS"
.PP
\-S \fI\fR
.RS 4
Updates the seeding value\&. A positive value will enable seeding, zero will disable seeding, negtive is not allowed\&. Enable seeding forces a fs readonly so that you can use it to build other filesystems\&.
.RE
.PP
\-r
.RS 4
Enable extended inode refs\&.
.RE
.PP
\-x
.RS 4
Enable skinny metadata extent refs\&.
.RE
.PP
\-f
.RS 4
Allow dangerous changes, e\&.g\&. clear the seeding flag
.RE
.sp
When mounting the new device, btrfs will check whether the seeding flag is set when try to open seeding device\&. If the user clears the seeding flag of the seeding device, the new device will not be mountable\&. Even setting the seeding flag back will not fix this problem, because the generation will be changed at that time\&. Clear the seeding flag may damage the new filesystem\&.
.SH "EXIT STATUS"
.sp
\fBbtrfstune\fR will return 0 if no error happened\&. If any problems happened, 1 will be returned\&.
.SH "SEE ALSO"
.sp
\fBmkfs\&.btrfs\fR(8)