.\"  Copyright (C) 2007-2012 Nippon Telegraph and Telephone Corporation.
.\"  Written by Ryusuke Konishi <konishi.ryusuke@gmail.com>
.\"
.TH LSSU 1 "Apr 2014" "nilfs-utils version 2.2"
.SH NAME
lssu \- list usage state of NILFS2 segments
.SH SYNOPSIS
.B lssu
[\fIoptions\fP] [\fIdevice\fP]
.SH DESCRIPTION
.B lssu
is a utility for displaying usage state of NILFS2 segments in
\fIdevice\fP, where a segment is contiguous lump of disk blocks and
an allocation unit of NILFS2 disk space.  When \fIdevice\fP is
omitted, \fI/proc/mounts\fP is examined to find a NILFS2 file system.
.PP
This command will fail if the \fIdevice\fP has no active mounts of a
NILFS2 file system.
.SH OPTIONS
.TP
\fB\-a\fR, \fB\-\-all\fR
Do not hide clean segments.
.TP
\fB\-h\fR, \fB\-\-help\fR
Display help message and exit.
.TP
\fB\-i \fIindex\fR, \fB\-\-index\fR=\fIindex\fR
Skip \fIindex\fP segments at start of input.
.TP
\fB\-l\fR, \fB\-\-latest-usage\fR
Print usage status of the moment.
.TP
\fB\-n \fIlines\fR, \fB\-\-lines\fR=\fIlines\fR
List only \fIlines\fP input segments.
.TP
\fB\-p \fIperiod\fR, \fB\-\-protection-period\fR=\fIperiod\fR
Specify protection period.  This option is used when printing usage
status of the moment (with \fB\-l\fR option) to test if each block in
segments is protected and is not reclaimable.  Optionally, the
\fIperiod\fP parameter may be suffixed by one of the following units
designators: \'s\', \'m\', \'h\', \'d\',\'w\',\'M\', or \'Y\', for
seconds, minutes, hours, days, weeks, months, or years, respectively.
.TP
\fB\-V\fR, \fB\-\-version\fR
Display version and exit.
.SH "FIELD DESCRIPTION"
Every line of the \fBlssu\fP output consists of the following fields:
.TP
.B SEGNUM
Segment number.
.TP
.B DATE
Creation date.
.TP
.B TIME
Creation time.
.TP
.B STAT
State of the segment.  It consists of the following flags:
.RS
.TP
.B a
The segment is active, meaning that it is recently created and cannot
be reclaimed by the garbage collector.
.TP
.B d
The segment is dirty, meaning that it is in use.
.TP
.B e
The segment is erroneous, meaning that it has once caused an I/O
error.  NILFS2 avoids allocating the segments with this flag.
.TP
.B p (optional)
The segment is protected, meaning that garbage collection for the
segment is prevented for some reason, for instance, the protection
period is not elapsed from its last modified time, the segment is
pinned by the file system, or it is erroneous and unreclaimable, etc.
This flag is displayed when \fB\-l\fR option is specified.
.RE
.TP
.B NBLOCKS
Number of in-use blocks of the segment.
.TP
.B NLIVEBLOCKS (optional)
Number and ratio of in-use blocks of the moment.  This field is
displayed when \fB\-l\fR option is specified.
.SH AUTHOR
Koji Sato
.SH AVAILABILITY
.B lssu
is part of the nilfs-utils package and is available from
https://nilfs.sourceforge.io.
.SH SEE ALSO
.BR nilfs (8),
.BR dumpseg (8).