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File: [cvs.NetBSD.org] / src / sbin / mount_nilfs / mount_nilfs.c (download)

Revision 1.1, Sat Jul 18 16:31:42 2009 UTC (10 years, 10 months ago) by reinoud
Branch: MAIN
CVS Tags: yamt-pagecache-tag8, yamt-pagecache-base8, yamt-pagecache-base7, yamt-pagecache-base6, yamt-pagecache-base5, yamt-pagecache-base4, yamt-pagecache-base3, yamt-pagecache-base2, yamt-pagecache-base, riastradh-drm2-base2, riastradh-drm2-base1, riastradh-drm2-base, riastradh-drm2, netbsd-6-base, netbsd-6-1-RELEASE, netbsd-6-1-RC4, netbsd-6-1-RC3, netbsd-6-1-RC2, netbsd-6-1-RC1, netbsd-6-1-5-RELEASE, netbsd-6-1-4-RELEASE, netbsd-6-1-3-RELEASE, netbsd-6-1-2-RELEASE, netbsd-6-1-1-RELEASE, netbsd-6-1, netbsd-6-0-RELEASE, netbsd-6-0-RC2, netbsd-6-0-RC1, netbsd-6-0-6-RELEASE, netbsd-6-0-5-RELEASE, netbsd-6-0-4-RELEASE, netbsd-6-0-3-RELEASE, netbsd-6-0-2-RELEASE, netbsd-6-0-1-RELEASE, netbsd-6-0, netbsd-6, matt-premerge-20091211, matt-nb6-plus-nbase, matt-nb6-plus-base, matt-nb6-plus, matt-mips64-premerge-20101231, cherry-xenmp-base, cherry-xenmp, bouyer-quota2-nbase, bouyer-quota2-base, bouyer-quota2, agc-symver-base, agc-symver
Branch point for: yamt-pagecache, tls-maxphys

Import read-only part of the NiLFS (v2) implementation for NetBSD. It has been
tested with a DEBUG+DIAGNOSTIC+LOCKDEBUG kernel. To summerise NiLFS, i'll
repeat my posting to tech-kern here:

NiLFS stands for New implementation of Logging File System; LFS done
right they claim :) It is at version 2 now and is being developed by NTT, the
Japanese telecom company and recently put into the linux source tree. See
http://www.nilfs.org. The on-disc format is not completely frozen and i expect
at least one minor revision to come in time.

The benefits of NiLFS are build-in fine-grained checkpointing, persistent
snapshots, multiple mounts and very large file and media support. Every
checkpoint can be transformed into a snapshot and v.v. It is said to perform
very well on flash media since it is not overwriting pieces apart from a
incidental update of the superblock, but that might change. It is accompanied
by a cleaner to clean up the segments and recover lost space.

My work is not a port of the linux code; its a new implementation. Porting the
code would be more work since its very linux oriented and never written to be
ported outside linux. The goal is to be fully interchangable. The code is non
intrusive to other parts of the kernel. It is also very light-weight.

The current state of the code is read-only access to both clean and dirty
NiLFS partitions. On mounting a dirty partition it rolls forward the log to
the last checkpoint. Full read-write support is however planned!

Just as the linux code, mount_nilfs allows for the `head' to be mounted
read/write and allows multiple read-only snapshots/checkpoint mounts next to
it.

By allowing the RW mount at a different snapshot for read-write it should be
possible eventually to revert back to a previous state; i.e. try to upgrade a
system and being able to revert to the exact state prior to the upgrade.

Compared to other FS's its pretty light-weight, suitable for embedded use and
on flash media. The read-only code is currently 17kb object code on
NetBSD/i386. I doubt the read-write code will surpass the 50 or 60. Compared
this to FFS being 156kb, UDF being 84 kb and NFS being 130kb. Run-time memory
usage is most likely not very different from other uses though maybe a bit
higher than FFS.

/* $NetBSD: mount_nilfs.c,v 1.1 2009/07/18 16:31:42 reinoud Exp $ */

/*
 * Copyright (c) 2008, 2009 Reinoud Zandijk
 * All rights reserved.
 * 
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *          This product includes software developed for the
 *          NetBSD Project.  See http://www.NetBSD.org/ for
 *          information about NetBSD.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 * 
 */


#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: mount_nilfs.c,v 1.1 2009/07/18 16:31:42 reinoud Exp $");
#endif /* not lint */


#include <sys/param.h>
#include <sys/mount.h>
#include <sys/stat.h>

#include <assert.h>
#include <err.h>
#include <errno.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <util.h>


/* mount specific options */
#include <fs/nilfs/nilfs_mount.h>
#include <mntopts.h>

#include "mountprog.h"
#include "mount_nilfs.h"

/* options to pass on to the `mount' call */
static const struct mntopt mopts[] = {
	MOPT_STDOPTS,		/* `normal' options		*/
	MOPT_ASYNC,		/* default			*/
	MOPT_NOATIME,		/* dont update access times	*/
	MOPT_UPDATE,		/* not yet supported		*/
	MOPT_GETARGS,		/* printing			*/
	MOPT_NULL,
};


/* prototypes */
static void	usage(void) __dead;


/* code */

static void
usage(void)
{
	(void)fprintf(stderr, "Usage: %s [-o options] [-c cpno] "
	    "[-t gmtoff] special node\n", getprogname());
	exit(EXIT_FAILURE);
}


#ifndef MOUNT_NOMAIN
int
main(int argc, char **argv)
{

	setprogname(argv[0]);
	return mount_nilfs(argc, argv);
}
#endif


/* main routine */
void
mount_nilfs_parseargs(int argc, char **argv,
	struct nilfs_args *args, int *mntflags,
	char *canon_dev, char *canon_dir)
{
	struct tm *tm;
	time_t	 now;
	int	 ch, set_gmtoff;
	uint32_t sector_size;
	mntoptparse_t mp;

	/* initialise */
	(void)memset(args, 0, sizeof(*args));

	set_gmtoff = *mntflags = 0;
	sector_size = 0;

	while ((ch = getopt(argc, argv, "c:o:t:")) != -1) {
		switch (ch) {
		case 'o' :
			/* process generic mount options */
			mp = getmntopts(optarg, mopts, mntflags, 0);
			if (mp == NULL)
				err(EXIT_FAILURE, "getmntopts");
			freemntopts(mp);
			break;
		case 'c' :
			args->cpno = a_num(optarg, "checkpoint number");
			break;
		case 't' :
			args->gmtoff = a_num(optarg, "gmtoff");
			set_gmtoff  = 1;
			break;
		default  :
			usage();
			/* NOTREACHED */
		}
	}

	if (optind + 2 != argc)
		usage();

	if (!set_gmtoff) {
		/* use user's time zone as default */
		(void)time(&now);
		tm = localtime(&now);
		args->gmtoff = tm->tm_gmtoff;
	}

	/* get device and directory specifier */
	pathadj(argv[optind], canon_dev);
	pathadj(argv[optind+1], canon_dir);

	args->version = NILFSMNT_VERSION;
	args->fspec = canon_dev;
}

int
mount_nilfs(int argc, char *argv[])
{
	struct nilfs_args args;
	char canon_dev[MAXPATHLEN], canon_dir[MAXPATHLEN];
	int mntflags;

	mount_nilfs_parseargs(argc, argv, &args, &mntflags, canon_dev, canon_dir);

	/* mount it! :) */
	if (mount(MOUNT_NILFS, canon_dir, mntflags, &args, sizeof args) == -1)
		err(EXIT_FAILURE, "Cannot mount %s on %s", canon_dev,canon_dir);

	if (mntflags & MNT_GETARGS) {
		char buf[1024];

		(void)snprintb(buf, sizeof(buf), NILFSMNT_BITS,
		    (uint64_t)args.nilfsmflags);
		(void)printf("gmtoffset = %d, cpno = %"PRIu64", flags = %s\n",
		    args.gmtoff, args.cpno, buf);
	}

	return EXIT_SUCCESS;
}