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+.TH FSFREEZE 8 "July 2014" "util-linux" "System Administration"
+.SH NAME
+fsfreeze \- suspend access to a filesystem (Ext3/4, ReiserFS, JFS, XFS)
+.SH SYNOPSIS
+.B fsfreeze
+.BR \--freeze | \--unfreeze
+.I mountpoint
+
+.SH DESCRIPTION
+.B fsfreeze
+suspends or resumes access to a filesystem.
+.PP
+.B fsfreeze
+halts any new access to the filesystem and creates a stable image on disk.
+.B fsfreeze
+is intended to be used with hardware RAID devices that support the creation
+of snapshots.
+.PP
+.B fsfreeze
+is unnecessary for
+.B device-mapper
+devices.  The device-mapper (and LVM) automatically freezes a filesystem
+on the device when a snapshot creation is requested.
+For more details see the
+.BR dmsetup (8)
+man page.
+.PP
+The
+.I mountpoint
+argument is the pathname of the directory where the filesystem
+is mounted.
+The filesystem must be mounted to be frozen (see
+.BR mount (8)).
+.PP
+Note that access-time updates are also suspended if the filesystem is mounted with
+the traditional atime behavior (mount option \fBstrictatime\fR, for more details see
+.BR mount (8)).
+
+.SH OPTIONS
+.TP
+.BR \-f , " \-\-freeze"
+This option requests the specified a filesystem to be frozen from new
+modifications.  When this is selected, all ongoing transactions in the
+filesystem are allowed to complete, new write system calls are halted, other
+calls which modify the filesystem are halted, and all dirty data, metadata, and
+log information are written to disk.  Any process attempting to write to the
+frozen filesystem will block waiting for the filesystem to be unfrozen.
+.sp
+Note that even after freezing, the on-disk filesystem can contain
+information on files that are still in the process of unlinking.
+These files will not be unlinked until the filesystem is unfrozen
+or a clean mount of the snapshot is complete.
+.TP
+.BR \-u , " \-\-unfreeze"
+This option is used to un-freeze the filesystem and allow operations to
+continue.  Any filesystem modifications that were blocked by the freeze are
+unblocked and allowed to complete.
+.TP
+.BR \-V , " \-\-version"
+Display version information and exit.
+.TP
+.BR \-h , " \-\-help"
+Display help text and exit.
+.SH FILESYSTEM SUPPORT
+This command will work only if filesystem supports has support for freezing.
+List of these filesystems include (2016-12-18)
+.BR btrfs ,
+.BR ext2/3/4 ,
+.BR f2fs ,
+.BR jfs ,
+.BR nilfs2 ,
+.BR reiserfs ,
+and
+.BR xfs .
+Previous list may be incomplete, as more filesystems get support.  If in
+doubt easiest way to know if a filesystem has support is create a small
+loopback mount and test freezing it.
+.SH AUTHOR
+.PP
+Written by Hajime Taira.
+.SH NOTES
+.PP
+This man page is based on
+.BR xfs_freeze (8).
+.SH SEE ALSO
+.BR mount (8)
+.SH AVAILABILITY
+The fsfreeze command is part of the util-linux package and is available from
+https://www.kernel.org/pub/linux/utils/util-linux/.