--- /dev/null
+.\" -*- nroff -*-
+.TH FSFREEZE 8 "May 2010"
+.SH NAME
+fsfreeze \- suspend access to an filesystem (Linux Ext3/4, ReiserFS, JFS, XFS).
+.SH SYNOPSIS
+.B fsfreeze
+.RB \-f
+.I mountpoint
+
+.B fsfreeze
+.RB \-u
+.I mountpoint
+
+.SH DESCRIPTION
+.B fsfreeze
+suspends and resumes access to an filesystem
+.PP
+.B fsfreeze
+halts 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 unncessary for
+.B device-mapper
+devices. The device-mapper (and LVM)
+automatically freezes filesystem on the device when a snapshot creation is requested.
+For more details see the
+.BR dmsetup (8)
+man page.
+.PP
+The
+.I mount-point
+argument is the pathname of the directory where the filesystem
+is mounted.
+The filesystem must be mounted to be frozen (see
+.BR mount (8)).
+.SH OPTIONS
+.IP "\fB\-h, \-\-help\fP"
+Print help and exit.
+.IP "\fB\-f, \-\-freeze\fP"
+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.
+
+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.
+.IP "\fB\-u, \-\-unfreeze\fP
+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.
+.SH AUTHOR
+.PP
+Written by Hajime Taira.
+.SH NOTES
+.PP
+This man page based on xfs_freeze.
+One of
+.B \-f
+or
+.B \-u
+must be supplied to
+.BR fsfreeze .
+.SH SEE ALSO
+.BR mount (8)
+.SH AVAILABILITY
+The fsfreeze command is part of the util-linux-ng package and is available from
+ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.
+
--- /dev/null
+/*
+ * fsfreeze.c -- Filesystem freeze/unfreeze IO for Linux
+ *
+ * Copyright (C) 2010 Hajime Taira <htaira@redhat.com>
+ * Masatake Yamato <yamato@redhat.com>
+ *
+ * This program is free software. You can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation: either version 1 or
+ * (at your option) any later version.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <fcntl.h>
+#include <linux/fs.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <getopt.h>
+#include <err.h>
+
+#include "blkdev.h"
+#include "nls.h"
+#include "c.h"
+
+static int freeze_f(int fd)
+{
+ return ioctl(fd, FIFREEZE, 0);
+}
+
+static int unfreeze_f(int fd)
+{
+ return ioctl(fd, FITHAW, 0);
+}
+
+static void __attribute__((__noreturn__)) usage(FILE *out)
+{
+ fprintf(out, _("Usage: %s [options] <mount point>\n\nOptions:\n"),
+ program_invocation_short_name);
+
+ fprintf(out, _(
+ " -h, --help this help\n"
+ " -f, --freeze freeze the filesystem\n"
+ " -u, --unfreeze unfreeze the filesystem\n"));
+
+ fprintf(out, _("\nFor more information see fsfreeze(8).\n"));
+
+ exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
+}
+
+int main(int argc, char **argv)
+{
+ int fd = -1, c;
+ int freeze = -1, rc = EXIT_FAILURE;
+ char *path;
+ struct stat sb;
+
+ struct option longopts[] = {
+ { "help", 0, 0, 'h' },
+ { "freeze", 0, 0, 'f' },
+ { "unfreeze", 0, 0, 'u' },
+ { NULL, 0, 0, 0 }
+ };
+
+ setlocale(LC_ALL, "");
+ bindtextdomain(PACKAGE, LOCALEDIR);
+ textdomain(PACKAGE);
+
+ while ((c = getopt_long(argc, argv, "hfu", longopts, NULL)) != -1) {
+ switch(c) {
+ case 'h':
+ usage(stdout);
+ break;
+ case 'f':
+ freeze = TRUE;
+ break;
+ case 'u':
+ freeze = FALSE;
+ break;
+ default:
+ usage(stderr);
+ break;
+ }
+ }
+
+ if (freeze == -1)
+ errx(EXIT_FAILURE, _("no action specified"));
+ if (optind == argc)
+ errx(EXIT_FAILURE, _("no filename specified"));
+ path = argv[optind++];
+
+ if (optind != argc) {
+ warnx(_("unexpected number of arguments"));
+ usage(stderr);
+ }
+
+ fd = open(path, O_RDONLY);
+ if (fd < 0)
+ err(EXIT_FAILURE, _("%s: open failed"), path);
+
+ if (fstat(fd, &sb) == -1) {
+ warn(_("%s: fstat failed"), path);
+ goto done;
+ }
+
+ if (!S_ISDIR(sb.st_mode)) {
+ warnx(_("%s: is not a directory"), path);
+ goto done;
+ }
+
+ if (freeze) {
+ if (freeze_f(fd)) {
+ warn(_("%s: freeze failed"), path);
+ goto done;
+ }
+ } else {
+ if (unfreeze_f(fd)) {
+ warn(_("%s: unfreeze failed"), path);
+ goto done;
+ }
+ }
+
+ rc = EXIT_SUCCESS;
+done:
+ if (fd >= 0)
+ close(fd);
+ return rc;
+}
+
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