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Message-ID: <CAPTn0cBe03jMxnBnBdmA1UJDnTTL1sJyZ+c91qCHv6_vaVvYdw@mail.gmail.com>
Date: Thu, 28 Nov 2013 09:37:33 +0800
From: Li Xi <pkuelelixi@...il.com>
To: "Darrick J. Wong" <darrick.wong@...cle.com>
Cc: linux-ext4@...r.kernel.org, Shuichi Ihara <sihara@....com>
Subject: Re: Patch of adding utility to check the status of MMP
Thanks a lot for your review and feedback! I've updated the patch
which fixes the defects that you pointed out. Would you please have a
lot at it again?
Thanks,
Li Xi
Signed-off-by: Li Xi <lixi@....com>
---
Index: e2fsprogs.git/e2fsprogs.spec.in
===================================================================
--- e2fsprogs.git.orig/e2fsprogs.spec.in
+++ e2fsprogs.git/e2fsprogs.spec.in
@@ -132,6 +132,7 @@ exit 0
%{_root_sbindir}/mkfs.ext4dev
%{_root_sbindir}/resize2fs
%{_root_sbindir}/tune2fs
+%{_root_sbindir}/mmpstatus
%{_sbindir}/filefrag
%{_sbindir}/mklost+found
%{_sbindir}/e2freefrag
@@ -180,6 +181,7 @@ exit 0
%{_mandir}/man8/tune2fs.8*
%{_mandir}/man8/filefrag.8*
%{_mandir}/man8/e2freefrag.8*
+%{_mandir}/man8/mmpstatus.8*
%files devel
%defattr(-,root,root)
Index: e2fsprogs.git/misc/mmpstatus.8.in
===================================================================
--- /dev/null
+++ e2fsprogs.git/misc/mmpstatus.8.in
@@ -0,0 +1,58 @@
+.\" -*- nroff -*-
+.\" This file may be copied under the terms of the GNU Public License.
+.\"
+.TH MMPSTATUS 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs
version @E2FSPROGS_VERSION@"
+.SH NAME
+mmpstatus \- Check MMP status of an ext4 file system
+.SH SYNOPSIS
+.B mmpstatus
+[
+.B \-c | \--check
+]
+[
+.B \-n | \--nodename
+]
+.I [filesys]
+.SH DESCRIPTION
+.B mmpstatus
+is used to check MMP status of an ext4 file system.
+.I filesys
+can be a device name (e.g.
+.IR /dev/hdc1 ", " /dev/sdb2 ),
+or an ext4 label or UUID specifier (e.g.
+UUID=8868abf6-88c5-4a83-98b8-bfc24057f7bd or LABEL=root).
+The
+.B mmpstatus
+program checks whether it is safe to mount the file system without taking
+the risk of mounting it more than once.
+.PP
+MMP (multiple-mount protection) is a feature which protects
+the file system from being mounted simultaneously to more than one node.
+It is NOT safe to mount a file system when one of the following condition
+is true:
+.br
+\ 1. The MMP shows that fsck is running on the file system.
+.br
+\ 2. The MMP are being updated by some node.
+.br
+The
+.B mmpstatus
+program might wait for some time to see whether MMP is updated by any node
+during this period.
+.PP
+Normaly, the exit code returned by
+.B mmpstatus
+is 0 when it is safe to mount the filesystem, 1 when it is NOT safe to mount
+the filesystem, and -1 on failure. When
+.B \-i
+flag is specified, the exit code
+is 0 on success, -1 on failure.
+.SH OPTIONS
+.TP
+.B \-i,
+Display the MMP field values rather than check them.
+.SH SEE ALSO
+.BR debugfs (8),
+.BR dumpe2fs (8),
+.BR tune2fs (8),
+.BR fsck (8)
Index: e2fsprogs.git/misc/Makefile.in
===================================================================
--- e2fsprogs.git.orig/misc/Makefile.in
+++ e2fsprogs.git/misc/Makefile.in
@@ -27,12 +27,12 @@ INSTALL = @INSTALL@
@BLKID_CMT@...DFS_MAN= findfs.8
SPROGS= mke2fs badblocks tune2fs dumpe2fs $(BLKID_PROG) logsave \
- $(E2IMAGE_PROG) @FSCK_PROG@ e2undo
+ $(E2IMAGE_PROG) @FSCK_PROG@ @MMPSTATUS_PROG@ e2undo
USPROGS= mklost+found filefrag e2freefrag $(UUIDD_PROG) $(E4DEFRAG_PROG)
SMANPAGES= tune2fs.8 mklost+found.8 mke2fs.8 dumpe2fs.8 badblocks.8 \
e2label.8 $(FINDFS_MAN) $(BLKID_MAN) $(E2IMAGE_MAN) \
logsave.8 filefrag.8 e2freefrag.8 e2undo.8 \
- $(UUIDD_MAN) $(E4DEFRAG_MAN) @FSCK_MAN@
+ $(UUIDD_MAN) $(E4DEFRAG_MAN) @FSCK_MAN@ @MMPSTATUS_MAN@
FMANPAGES= mke2fs.conf.5
UPROGS= chattr lsattr @UUID_CMT@ uuidgen
@@ -51,6 +51,7 @@ DUMPE2FS_OBJS= dumpe2fs.o
BADBLOCKS_OBJS= badblocks.o
E2IMAGE_OBJS= e2image.o
FSCK_OBJS= fsck.o base_device.o ismounted.o
+MMPSTATUS_OBJS= mmpstatus.o
BLKID_OBJS= blkid.o
FILEFRAG_OBJS= filefrag.o
E2UNDO_OBJS= e2undo.o
@@ -70,6 +71,7 @@ PROFILED_BADBLOCKS_OBJS= profiled/badblo
PROFILED_E2IMAGE_OBJS= profiled/e2image.o
PROFILED_FSCK_OBJS= profiled/fsck.o profiled/base_device.o \
profiled/ismounted.o
+PROFILED_MMPSTATUS_OBJS=profiled/mmpstatus.o
PROFILED_BLKID_OBJS= profiled/blkid.o
PROFILED_FILEFRAG_OBJS= profiled/filefrag.o
PROFILED_E2FREEFRAG_OBJS= profiled/e2freefrag.o
@@ -82,7 +84,8 @@ SRCS= $(srcdir)/tune2fs.c $(srcdir)/mklo
$(srcdir)/uuidgen.c $(srcdir)/blkid.c $(srcdir)/logsave.c \
$(srcdir)/filefrag.c $(srcdir)/base_device.c \
$(srcdir)/ismounted.c $(srcdir)/../e2fsck/profile.c \
- $(srcdir)/e2undo.c $(srcdir)/e2freefrag.c
+ $(srcdir)/e2undo.c $(srcdir)/e2freefrag.c \
+ $(srcdir)/mmpstatus.c
LIBS= $(LIBEXT2FS) $(LIBCOM_ERR)
DEPLIBS= $(LIBEXT2FS) $(DEPLIBCOM_ERR)
@@ -300,6 +303,16 @@ fsck.profiled: $(FSCK_OBJS) $(PROFILED_D
$(Q) $(CC) $(ALL_LDFLAGS) -g -pg -o fsck.profiled $(PROFILED_FSCK_OBJS) \
$(PROFILED_LIBBLKID) $(LIBINTL)
+mmpstatus: $(MMPSTATUS_OBJS) $(DEPLIBBLKID)
+ $(E) " LD $@"
+ $(Q) $(CC) $(ALL_LDFLAGS) -o mmpstatus $(MMPSTATUS_OBJS) $(LIBBLKID) \
+ $(LIBINTL) $(LIBS)
+
+mmpstatus.profiled: $(MMPSTATUS_OBJS) $(PROFILED_DEPLIBBLKID)
+ $(E) " LD $@"
+ $(Q) $(CC) $(ALL_LDFLAGS) -g -pg -o mmpstatus.profiled \
+ $(PROFILED_MMPSTATUS_OBJS) $(PROFILED_LIBBLKID) $(LIBINTL)
+
badblocks: $(BADBLOCKS_OBJS) $(DEPLIBS)
$(E) " LD $@"
$(Q) $(CC) $(ALL_LDFLAGS) -o badblocks $(BADBLOCKS_OBJS) $(LIBS) $(LIBINTL)
@@ -384,6 +397,10 @@ badblocks.8: $(DEP_SUBSTITUTE) $(srcdir)
$(E) " SUBST $@"
$(Q) $(SUBSTITUTE_UPTIME) $(srcdir)/badblocks.8.in badblocks.8
+mmpstatus.8: $(DEP_SUBSTITUTE) $(srcdir)/mmpstatus.8.in
+ $(E) " SUBST $@"
+ $(Q) $(SUBSTITUTE_UPTIME) $(srcdir)/mmpstatus.8.in mmpstatus.8
+
fsck.8: $(DEP_SUBSTITUTE) $(srcdir)/fsck.8.in
$(E) " SUBST $@"
$(Q) $(SUBSTITUTE_UPTIME) $(srcdir)/fsck.8.in fsck.8
@@ -575,7 +592,8 @@ clean:
e2undo.profiled mke2fs.profiled dumpe2fs.profiled \
logsave.profiled filefrag.profiled uuidgen.profiled \
uuidd.profiled e2image.profiled mke2fs.conf \
- profiled/*.o \#* *.s *.o *.a *~ core gmon.out
+ mmpstatus.profiled profiled/*.o \#* *.s *.o *.a *~ core \
+ gmon.out
mostlyclean: clean
distclean: clean
@@ -644,6 +662,9 @@ badblocks.o: $(srcdir)/badblocks.c $(top
fsck.o: $(srcdir)/fsck.c $(top_builddir)/lib/config.h \
$(top_builddir)/lib/dirpaths.h $(top_srcdir)/version.h \
$(srcdir)/nls-enable.h $(srcdir)/fsck.h
+mmpstatus.o: $(srcdir)/mmpstatus.c $(top_builddir)/lib/config.h \
+ $(top_builddir)/lib/dirpaths.h $(top_srcdir)/version.h \
+ $(srcdir)/nls-enable.h $(top_srcdir)/lib/ext2fs/ext2fs.h
util.o: $(srcdir)/util.c $(top_builddir)/lib/config.h \
$(top_builddir)/lib/dirpaths.h $(top_srcdir)/lib/et/com_err.h \
$(top_srcdir)/lib/e2p/e2p.h $(top_srcdir)/lib/ext2fs/ext2_fs.h \
Index: e2fsprogs.git/misc/mmpstatus.c
===================================================================
--- /dev/null
+++ e2fsprogs.git/misc/mmpstatus.c
@@ -0,0 +1,103 @@
+/*
+ * mmpstatus.c --- check MMP status of an ext4 file system
+ *
+ * Copyright (C) 2013 DataDirect Networks, Inc.
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ * %End-Header%
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <time.h>
+#include <getopt.h>
+#include <sys/time.h>
+#include "ext2fs/ext2fs.h"
+#include "blkid/blkid.h"
+#include "../version.h"
+#include "nls-enable.h"
+
+/*
+ * return 1 when MMP is being updated,
+ * 0 if not, and -1 on falure
+*/
+int main (int argc, char ** argv)
+{
+ char *device;
+ int open_flags = EXT2_FLAG_64BITS;
+ ext2_filsys filesystem = NULL;
+ int retval;
+ const char *usage =
+ "usage: %s [-i] device";
+ int c;
+ int info = 0;
+ const char *debug_prog_name = "mmpstatus";
+
+ add_error_table(&et_ext2_error_table);
+ fprintf(stderr, "%s %s (%s)\n", debug_prog_name,
+ E2FSPROGS_VERSION, E2FSPROGS_DATE);
+ while ((c = getopt(argc, argv, "i")) != EOF) {
+ switch (c) {
+ case 'i':
+ info++;
+ break;
+ default:
+ com_err(argv[0], 0, usage, debug_prog_name);
+ return -1;
+ }
+ }
+
+ if (optind != argc - 1) {
+ com_err(argv[0], 0, usage, debug_prog_name);
+ return -1;
+ }
+
+ device = blkid_get_devname(NULL, argv[optind], NULL);
+ if (device == NULL) {
+ com_err(argv[0], 0, _("Unable to resolve '%s'"), device);
+ return -1;
+ }
+
+ retval = ext2fs_open(device, open_flags, 0, 0,
+ unix_io_manager, &filesystem);
+ if (retval) {
+ com_err(argv[0], retval, _("while trying to open %s"),
+ device);
+ retval = -1;
+ goto out_free_device;
+ }
+
+ if (info) {
+ retval = ext2fs_mmp_dump(filesystem);
+ if (retval) {
+ com_err(argv[0], retval, _("while trying to dump %s"),
+ device);
+ }
+ } else {
+ retval = ext2fs_mmp_start(filesystem);
+ switch (retval) {
+ case EXT2_ET_MMP_FAILED:
+ com_err(argv[0], retval,
+ _("while checking MMP status of %s"), device);
+ retval = 1;
+ break;
+ case 0:
+ com_err(argv[0], 0, "device '%s' is not used now\n",
+ device);
+ break;
+ default:
+ com_err(argv[0], retval,
+ _("while checking MMP status of %s"), device);
+ retval = -1;
+ break;
+ }
+ }
+ ext2fs_close(filesystem);
+out_free_device:
+ free(device);
+ return retval;
+}
Index: e2fsprogs.git/configure.in
===================================================================
--- e2fsprogs.git.orig/configure.in
+++ e2fsprogs.git/configure.in
@@ -718,6 +718,32 @@ esac]
AC_SUBST(FSCK_PROG)
AC_SUBST(FSCK_MAN)
dnl
+dnl See whether to install the `mmpstatus' program
+dnl
+AC_ARG_ENABLE([mmpstatus],
+[ --enable-mmpstatus build mmpstatus program],
+[if test "$enableval" = "no"
+then
+ MMPSTATUS_PROG='' MMPSTATUS_MAN=''
+ AC_MSG_RESULT([Not building mmpstatus])
+else
+ MMPSTATUS_PROG=mmpstatus MMPSTATUS_MAN=mmpstatus.8
+ AC_MSG_RESULT([Building mmpstatus])
+fi]
+,
+[case "$host_os" in
+ gnu*)
+ MMPSTATUS_PROG='' MMPSTATUS_MAN=''
+ AC_MSG_RESULT([Not building mmpstatus by default])
+ ;;
+ *)
+ MMPSTATUS_PROG=mmpstatus MMPSTATUS_MAN=mmpstatus.8
+ AC_MSG_RESULT([Building mmpstatus by default])
+esac]
+)
+AC_SUBST(MMPSTATUS_PROG)
+AC_SUBST(MMPSTATUS_MAN)
+dnl
dnl See whether to install the `e2initrd-helper' program
dnl
AC_ARG_ENABLE([e2initrd-helper],
Index: e2fsprogs.git/debugfs/debugfs.c
===================================================================
--- e2fsprogs.git.orig/debugfs/debugfs.c
+++ e2fsprogs.git/debugfs/debugfs.c
@@ -2316,50 +2316,12 @@ try_again:
void do_dump_mmp(int argc EXT2FS_ATTR((unused)), char *argv[])
{
#if CONFIG_MMP
- struct ext2_super_block *sb;
- struct mmp_struct *mmp_s;
- time_t t;
- errcode_t retval = 0;
-
+ int retval;
if (check_fs_open(argv[0]))
return;
-
- sb = current_fs->super;
- if (sb->s_mmp_block <= sb->s_first_data_block ||
- sb->s_mmp_block >= ext2fs_blocks_count(sb)) {
- com_err(argv[0], EXT2_ET_MMP_BAD_BLOCK, "while dumping it.\n");
- return;
- }
-
- if (current_fs->mmp_buf == NULL) {
- retval = ext2fs_get_mem(current_fs->blocksize,
- ¤t_fs->mmp_buf);
- if (retval) {
- com_err(argv[0], retval, "allocating MMP buffer.\n");
- return;
- }
- }
-
- mmp_s = current_fs->mmp_buf;
-
- retval = ext2fs_mmp_read(current_fs, current_fs->super->s_mmp_block,
- current_fs->mmp_buf);
- if (retval) {
- com_err(argv[0], retval, "reading MMP block.\n");
- return;
- }
-
- t = mmp_s->mmp_time;
- fprintf(stdout, "block_number: %llu\n", current_fs->super->s_mmp_block);
- fprintf(stdout, "update_interval: %d\n",
- current_fs->super->s_mmp_update_interval);
- fprintf(stdout, "check_interval: %d\n", mmp_s->mmp_check_interval);
- fprintf(stdout, "sequence: %08x\n", mmp_s->mmp_seq);
- fprintf(stdout, "time: %lld -- %s", mmp_s->mmp_time, ctime(&t));
- fprintf(stdout, "node_name: %s\n", mmp_s->mmp_nodename);
- fprintf(stdout, "device_name: %s\n", mmp_s->mmp_bdevname);
- fprintf(stdout, "magic: 0x%x\n", mmp_s->mmp_magic);
- fprintf(stdout, "checksum: 0x%08x\n", mmp_s->mmp_checksum);
+ retval = ext2fs_mmp_dump(current_fs);
+ if (retval)
+ com_err(argv[0], retval, "while dumping it.\n");
#else
fprintf(stdout, "MMP is unsupported, please recompile with "
"--enable-mmp\n");
Index: e2fsprogs.git/lib/ext2fs/ext2fs.h
===================================================================
--- e2fsprogs.git.orig/lib/ext2fs/ext2fs.h
+++ e2fsprogs.git/lib/ext2fs/ext2fs.h
@@ -1468,6 +1468,7 @@ errcode_t ext2fs_symlink(ext2_filsys fs,
/* mmp.c */
errcode_t ext2fs_mmp_read(ext2_filsys fs, blk64_t mmp_blk, void *buf);
errcode_t ext2fs_mmp_write(ext2_filsys fs, blk64_t mmp_blk, void *buf);
+errcode_t ext2fs_mmp_dump(ext2_filsys fs);
errcode_t ext2fs_mmp_clear(ext2_filsys fs);
errcode_t ext2fs_mmp_init(ext2_filsys fs);
errcode_t ext2fs_mmp_start(ext2_filsys fs);
Index: e2fsprogs.git/lib/ext2fs/mmp.c
===================================================================
--- e2fsprogs.git.orig/lib/ext2fs/mmp.c
+++ e2fsprogs.git/lib/ext2fs/mmp.c
@@ -19,7 +19,7 @@
#include <unistd.h>
#endif
#include <sys/time.h>
-
+#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
@@ -259,6 +259,52 @@ out:
#endif
}
+errcode_t ext2fs_mmp_dump(ext2_filsys fs)
+{
+#ifdef CONFIG_MMP
+ struct ext2_super_block *sb;
+ struct mmp_struct *mmp_s;
+ time_t t;
+ errcode_t retval = 0;
+
+ sb = fs->super;
+ if (sb->s_mmp_block <= sb->s_first_data_block ||
+ sb->s_mmp_block >= ext2fs_blocks_count(sb)) {
+ return EXT2_ET_MMP_BAD_BLOCK;
+ }
+
+ if (fs->mmp_buf == NULL) {
+ retval = ext2fs_get_mem(fs->blocksize,
+ &fs->mmp_buf);
+ if (retval)
+ return retval;
+ }
+
+ mmp_s = fs->mmp_buf;
+
+ retval = ext2fs_mmp_read(fs, fs->super->s_mmp_block,
+ fs->mmp_buf);
+ if (retval)
+ return retval;
+
+ t = mmp_s->mmp_time;
+ fprintf(stdout, "block_number: %llu\n", fs->super->s_mmp_block);
+ fprintf(stdout, "update_interval: %d\n",
+ fs->super->s_mmp_update_interval);
+ fprintf(stdout, "check_interval: %d\n", mmp_s->mmp_check_interval);
+ fprintf(stdout, "sequence: %08x\n", mmp_s->mmp_seq);
+ fprintf(stdout, "time: %lld -- %s", mmp_s->mmp_time, ctime(&t));
+ fprintf(stdout, "node_name: %s\n", mmp_s->mmp_nodename);
+ fprintf(stdout, "device_name: %s\n", mmp_s->mmp_bdevname);
+ fprintf(stdout, "magic: 0x%x\n", mmp_s->mmp_magic);
+ fprintf(stdout, "checksum: 0x%08x\n", mmp_s->mmp_checksum);
+
+ return 0;
+#else
+ return EXT2_ET_OP_NOT_SUPPORTED;
+#endif
+}
+
/*
* Make sure that the fs is not mounted or being fsck'ed while opening the fs.
*/
2013/11/14 Darrick J. Wong <darrick.wong@...cle.com>:
> On Wed, Nov 13, 2013 at 08:07:35PM +0800, Li Xi wrote:
>> Hi all,
>>
>> MMP feature of ext4 really helps us a lot to avoid mounting file
>> system more than once, especailly when using ext4 as the basis of a
>> distributed file sytem, e.g. Lustre. However, lack of a userspace
>> utility to check the status of MMP makes it diffcult to utilize this
>> feature to make failover decisions. We tried to write a script to do
>> so by parsing the output of debugfs command. But this solution is not
>> very straight forward. In order to check the sequence and checksum
>> correctly, the script has to embed a lot of value definition, which
>> could be error prone.
>>
>> Finally, we decided to add a new command in the e2fsprogs. With that
>> command, a server is able to check the current MMP state of a device
>> so that it can decide whether to take over the file system service
>> from aother server. I think the patch might helps other use cases too.
>>
>> The attachment is the patch.
>>
>> Thanks,
>> Li Xi
>
> Please add a signed-off-by line.
>
> Also /me grumps about patch-as-attachment; inline is less cutting and pasting
> for review. :)
>
>> Index: e2fsprogs.git/e2fsprogs.spec.in
>> ===================================================================
>> --- e2fsprogs.git.orig/e2fsprogs.spec.in
>> +++ e2fsprogs.git/e2fsprogs.spec.in
>> @@ -132,6 +132,7 @@ exit 0
>> %{_root_sbindir}/mkfs.ext4dev
>> %{_root_sbindir}/resize2fs
>> %{_root_sbindir}/tune2fs
>> +%{_root_sbindir}/mmpstatus
>> %{_sbindir}/filefrag
>> %{_sbindir}/mklost+found
>> %{_sbindir}/e2freefrag
>> @@ -180,6 +181,7 @@ exit 0
>> %{_mandir}/man8/tune2fs.8*
>> %{_mandir}/man8/filefrag.8*
>> %{_mandir}/man8/e2freefrag.8*
>> +%{_mandir}/man8/mmpstatus.8*
>>
>> %files devel
>> %defattr(-,root,root)
>> Index: e2fsprogs.git/misc/mmpstatus.8.in
>> ===================================================================
>> --- /dev/null
>> +++ e2fsprogs.git/misc/mmpstatus.8.in
>> @@ -0,0 +1,56 @@
>> +.\" -*- nroff -*-
>> +.\" This file may be copied under the terms of the GNU Public License.
>> +.\"
>> +.TH MMPSTATUS 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
>> +.SH NAME
>> +mmpstatus \- Check MMP status of an ext4 file system
>> +.SH SYNOPSIS
>> +.B mmpstatus
>> +[
>> +.B \-c | \--check
>> +]
>> +[
>> +.B \-n | \--nodename
>> +]
>> +.I [filesys]
>> +.SH DESCRIPTION
>> +.B mmpstatus
>> +is used to check MMP status of an ext4 file system.
>> +.I filesys
>> +can be a device name (e.g.
>> +.IR /dev/hdc1 ", " /dev/sdb2 ),
>> +or an ext4 label or UUID specifier (e.g.
>> +UUID=8868abf6-88c5-4a83-98b8-bfc24057f7bd or LABEL=root).
>> +Normaly, the
>
> "Normally" (there are several of these)
>
>> +.B mmpstatus
>> +program checks whether it is safe to mount the file system without taking
>> +the risk of mounting it more than once.
>> +.PP
>> +MMP (multiple-mount protection) is a feature which protects
>> +the file system from being mounted simultaneously to more than one node.
>> +It is NOT safe to mount a file system when one of the following condition
>> +is true:
>> +.br
>> +\ 1. The MMP shows that fsck is running on the file system.
>> +.br
>> +\ 2. The MMP are being updated by some node.
>> +.br
>> +The
>> +.B mmpstatus
>> +program might wait for some time to see whether MMP is updated by any node
>> +during this period.
>> +.PP
>> +Normaly, The exit code returned by
>> +.B mmpstatus
>> +is 0 when it is safe to mount the filesystem, 1 when it is NOT safe to mount
>> +the filesystem, and -1 on failure. When
>> +.B \-i
>> +flag is specified, the exit code
>> +is 0 on success, -1 on failure.
>> +.SH OPTIONS
>> +.TP
>> +.B \-i,
>> +print out the MMP informantion rather than check it.
>
> "information"
>
>> +.SH SEE ALSO
>> +.BR fstab (5),
>> +.BR fsck (8),
>> Index: e2fsprogs.git/misc/Makefile.in
>> ===================================================================
>> --- e2fsprogs.git.orig/misc/Makefile.in
>> +++ e2fsprogs.git/misc/Makefile.in
>> @@ -27,12 +27,12 @@ INSTALL = @INSTALL@
>> @BLKID_CMT@...DFS_MAN= findfs.8
>>
>> SPROGS= mke2fs badblocks tune2fs dumpe2fs $(BLKID_PROG) logsave \
>> - $(E2IMAGE_PROG) @FSCK_PROG@ e2undo
>> + $(E2IMAGE_PROG) @FSCK_PROG@ @MMPSTATUS_PROG@ e2undo
>> USPROGS= mklost+found filefrag e2freefrag $(UUIDD_PROG) $(E4DEFRAG_PROG)
>> SMANPAGES= tune2fs.8 mklost+found.8 mke2fs.8 dumpe2fs.8 badblocks.8 \
>> e2label.8 $(FINDFS_MAN) $(BLKID_MAN) $(E2IMAGE_MAN) \
>> logsave.8 filefrag.8 e2freefrag.8 e2undo.8 \
>> - $(UUIDD_MAN) $(E4DEFRAG_MAN) @FSCK_MAN@
>> + $(UUIDD_MAN) $(E4DEFRAG_MAN) @FSCK_MAN@ @MMPSTATUS_MAN@
>> FMANPAGES= mke2fs.conf.5
>>
>> UPROGS= chattr lsattr @UUID_CMT@ uuidgen
>> @@ -51,6 +51,7 @@ DUMPE2FS_OBJS= dumpe2fs.o
>> BADBLOCKS_OBJS= badblocks.o
>> E2IMAGE_OBJS= e2image.o
>> FSCK_OBJS= fsck.o base_device.o ismounted.o
>> +MMPSTATUS_OBJS= mmpstatus.o
>> BLKID_OBJS= blkid.o
>> FILEFRAG_OBJS= filefrag.o
>> E2UNDO_OBJS= e2undo.o
>> @@ -70,6 +71,7 @@ PROFILED_BADBLOCKS_OBJS= profiled/badblo
>> PROFILED_E2IMAGE_OBJS= profiled/e2image.o
>> PROFILED_FSCK_OBJS= profiled/fsck.o profiled/base_device.o \
>> profiled/ismounted.o
>> +PROFILED_MMPSTATUS_OBJS=profiled/mmpstatus.o
>> PROFILED_BLKID_OBJS= profiled/blkid.o
>> PROFILED_FILEFRAG_OBJS= profiled/filefrag.o
>> PROFILED_E2FREEFRAG_OBJS= profiled/e2freefrag.o
>> @@ -82,7 +84,8 @@ SRCS= $(srcdir)/tune2fs.c $(srcdir)/mklo
>> $(srcdir)/uuidgen.c $(srcdir)/blkid.c $(srcdir)/logsave.c \
>> $(srcdir)/filefrag.c $(srcdir)/base_device.c \
>> $(srcdir)/ismounted.c $(srcdir)/../e2fsck/profile.c \
>> - $(srcdir)/e2undo.c $(srcdir)/e2freefrag.c
>> + $(srcdir)/e2undo.c $(srcdir)/e2freefrag.c \
>> + $(srcdir)/mmpstatus.c
>>
>> LIBS= $(LIBEXT2FS) $(LIBCOM_ERR)
>> DEPLIBS= $(LIBEXT2FS) $(DEPLIBCOM_ERR)
>> @@ -300,6 +303,16 @@ fsck.profiled: $(FSCK_OBJS) $(PROFILED_D
>> $(Q) $(CC) $(ALL_LDFLAGS) -g -pg -o fsck.profiled $(PROFILED_FSCK_OBJS) \
>> $(PROFILED_LIBBLKID) $(LIBINTL)
>>
>> +mmpstatus: $(MMPSTATUS_OBJS) $(DEPLIBBLKID)
>> + $(E) " LD $@"
>> + $(Q) $(CC) $(ALL_LDFLAGS) -o mmpstatus $(MMPSTATUS_OBJS) $(LIBBLKID) \
>> + $(LIBINTL) $(LIBS)
>> +
>> +mmpstatus.profiled: $(MMPSTATUS_OBJS) $(PROFILED_DEPLIBBLKID)
>> + $(E) " LD $@"
>> + $(Q) $(CC) $(ALL_LDFLAGS) -g -pg -o mmpstatus.profiled \
>> + $(PROFILED_MMPSTATUS_OBJS) $(PROFILED_LIBBLKID) $(LIBINTL)
>> +
>> badblocks: $(BADBLOCKS_OBJS) $(DEPLIBS)
>> $(E) " LD $@"
>> $(Q) $(CC) $(ALL_LDFLAGS) -o badblocks $(BADBLOCKS_OBJS) $(LIBS) $(LIBINTL)
>> @@ -384,6 +397,10 @@ badblocks.8: $(DEP_SUBSTITUTE) $(srcdir)
>> $(E) " SUBST $@"
>> $(Q) $(SUBSTITUTE_UPTIME) $(srcdir)/badblocks.8.in badblocks.8
>>
>> +mmpstatus.8: $(DEP_SUBSTITUTE) $(srcdir)/mmpstatus.8.in
>> + $(E) " SUBST $@"
>> + $(Q) $(SUBSTITUTE_UPTIME) $(srcdir)/mmpstatus.8.in mmpstatus.8
>> +
>> fsck.8: $(DEP_SUBSTITUTE) $(srcdir)/fsck.8.in
>> $(E) " SUBST $@"
>> $(Q) $(SUBSTITUTE_UPTIME) $(srcdir)/fsck.8.in fsck.8
>> @@ -575,7 +592,8 @@ clean:
>> e2undo.profiled mke2fs.profiled dumpe2fs.profiled \
>> logsave.profiled filefrag.profiled uuidgen.profiled \
>> uuidd.profiled e2image.profiled mke2fs.conf \
>> - profiled/*.o \#* *.s *.o *.a *~ core gmon.out
>> + mmpstatus.profiled profiled/*.o \#* *.s *.o *.a *~ core \
>> + gmon.out
>>
>> mostlyclean: clean
>> distclean: clean
>> @@ -644,6 +662,9 @@ badblocks.o: $(srcdir)/badblocks.c $(top
>> fsck.o: $(srcdir)/fsck.c $(top_builddir)/lib/config.h \
>> $(top_builddir)/lib/dirpaths.h $(top_srcdir)/version.h \
>> $(srcdir)/nls-enable.h $(srcdir)/fsck.h
>> +mmpstatus.o: $(srcdir)/mmpstatus.c $(top_builddir)/lib/config.h \
>> + $(top_builddir)/lib/dirpaths.h $(top_srcdir)/version.h \
>> + $(srcdir)/nls-enable.h $(top_srcdir)/lib/ext2fs/ext2fs.h
>> util.o: $(srcdir)/util.c $(top_builddir)/lib/config.h \
>> $(top_builddir)/lib/dirpaths.h $(top_srcdir)/lib/et/com_err.h \
>> $(top_srcdir)/lib/e2p/e2p.h $(top_srcdir)/lib/ext2fs/ext2_fs.h \
>> Index: e2fsprogs.git/misc/mmpstatus.c
>> ===================================================================
>> --- /dev/null
>> +++ e2fsprogs.git/misc/mmpstatus.c
>> @@ -0,0 +1,120 @@
>> +/*
>> + * GPL HEADER START
>> + *
>> + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 only,
>> + * as published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful, but
>> + * WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
>> + * General Public License version 2 for more details (a copy is included
>> + * in the LICENSE file that accompanied this code).
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * version 2 along with this program; if not, write to the
>> + * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
>> + * Boston, MA 021110-1307, USA
>> + *
>> + * GPL HEADER END
>> + */
>> +/*
>> + * Copyright (C) 2013 DataDirect Networks, Inc.
>> + */
>> +
>> +#include <stdio.h>
>> +#include <unistd.h>
>> +#include <stdlib.h>
>> +#include <assert.h>
>> +#include <time.h>
>> +#include <getopt.h>
>> +#include <sys/time.h>
>> +#include "ext2fs/ext2fs.h"
>> +#include "blkid/blkid.h"
>> +#include "../version.h"
>> +#include "nls-enable.h"
>> +
>> +/*
>> + * return 1 when MMP is being updated,
>> + * 0 if not, and -1 on falure
>> +*/
>> +int main (int argc, char ** argv)
>> +{
>> + char *device;
>> + int open_flags = 0;
>> + blk64_t superblock = 0;
>> + blk64_t blocksize = 0;
>> + ext2_filsys filesystem = NULL;
>> + int retval;
>> + const char *usage =
>> + "usage: %s [-i] device";
>> + const char *opt_string = "i";
>> + int c;
>> + int info = 0;
>> + const char *debug_prog_name = "mmpstatus";
>> +
>> + add_error_table(&et_ext2_error_table);
>> + fprintf(stderr, "%s %s (%s)\n", debug_prog_name,
>> + E2FSPROGS_VERSION, E2FSPROGS_DATE);
>> + while ((c = getopt(argc, argv, opt_string)) != EOF) {
>
> Probably fine to use the bare string "i" instead of opt_string here.
>
>> + switch (c) {
>> + case 'i':
>> + info++;
>> + break;
>> + default:
>> + com_err(argv[0], 0, usage, debug_prog_name);
>> + return -1;
>> + }
>> + }
>> +
>> + if (optind != argc - 1) {
>> + com_err(argv[0], 0, usage, debug_prog_name);
>> + return -1;
>> + }
>> +
>> + device = blkid_get_devname(NULL, argv[optind], NULL);
>> + if (device == NULL) {
>> + com_err(argv[0], 0, _("Unable to resolve '%s'"), device);
>> + return -1;
>> + }
>> +
>> + retval = ext2fs_open(device, open_flags, superblock, blocksize,
>> + unix_io_manager, &filesystem);
>
> You might want at least open_flags |= EXT2_FLAG_64BITS, because bigalloc FSes
> require features that get turned on with that flag, and will fail the open call
> if the flag isn't there.
>
> Also I could whine about argument size mismatches for superblock and blocksize;
> technically, both parameters are 32-bits yet the variables being passed in
> are 64 bits. Block size will never need 64 bits, and the ext2fs_open3() call
> to fix superblock hasn't gone in yet. Also, both variables are permanently
> zero, so you could just open code them and let the compiler figure it out.
>
>> + if (retval) {
>> + com_err(argv[0], retval, _("while trying to open %s"),
>> + device);
>> + retval = -1;
>> + goto out_free_device;
>> + }
>> +
>> + if (info) {
>> + retval = ext2fs_mmp_dump(filesystem);
>> + if (retval) {
>> + com_err(argv[0], retval, _("while trying to dump %s"),
>> + device);
>> + }
>> + } else {
>> + retval = ext2fs_mmp_start(filesystem);
>> + switch (retval) {
>> + case EXT2_ET_MMP_FAILED:
>> + com_err(argv[0], retval,
>> + _("while checking MMP status of %s"), device);
>> + retval = 1;
>> + break;
>> + case 0:
>> + com_err(argv[0], 0, "device '%s' is not used now\n",
>> + device);
>> + break;
>> + default:
>> + com_err(argv[0], retval,
>> + _("while checking MMP status of %s"), device);
>> + retval = -1;
>
> Picking nits here, but 'break'?
>
>> + }
>> + }
>> + ext2fs_close(filesystem);
>> +out_free_device:
>> + free(device);
>> + return retval;
>> +}
>> Index: e2fsprogs.git/configure.in
>> ===================================================================
>> --- e2fsprogs.git.orig/configure.in
>> +++ e2fsprogs.git/configure.in
>> @@ -718,6 +718,32 @@ esac]
>> AC_SUBST(FSCK_PROG)
>> AC_SUBST(FSCK_MAN)
>> dnl
>> +dnl See whether to install the `mmpstatus' program
>> +dnl
>> +AC_ARG_ENABLE([mmpstatus],
>> +[ --enable-mmpstatus build mmpstatus program],
>> +[if test "$enableval" = "no"
>> +then
>> + MMPSTATUS_PROG='' MMPSTATUS_MAN=''
>> + AC_MSG_RESULT([Not building mmpstatus])
>> +else
>> + MMPSTATUS_PROG=mmpstatus MMPSTATUS_MAN=mmpstatus.8
>> + AC_MSG_RESULT([Building mmpstatus])
>> +fi]
>> +,
>> +[case "$host_os" in
>> + gnu*)
>> + MMPSTATUS_PROG='' MMPSTATUS_MAN=''
>> + AC_MSG_RESULT([Not mmpstatus by default])
>
> "Not building mmpstatus"?
>
>> + ;;
>> + *)
>> + MMPSTATUS_PROG=mmpstatus MMPSTATUS_MAN=mmpstatus.8
>> + AC_MSG_RESULT([Building mmpstatus by default])
>> +esac]
>> +)
>> +AC_SUBST(MMPSTATUS_PROG)
>> +AC_SUBST(MMPSTATUS_MAN)
>> +dnl
>> dnl See whether to install the `e2initrd-helper' program
>> dnl
>> AC_ARG_ENABLE([e2initrd-helper],
>> Index: e2fsprogs.git/debugfs/debugfs.c
>> ===================================================================
>> --- e2fsprogs.git.orig/debugfs/debugfs.c
>> +++ e2fsprogs.git/debugfs/debugfs.c
>> @@ -2315,54 +2315,15 @@ try_again:
>>
>> void do_dump_mmp(int argc EXT2FS_ATTR((unused)), char *argv[])
>> {
>> + int retval;
>> #if CONFIG_MMP
>> - struct ext2_super_block *sb;
>> - struct mmp_struct *mmp_s;
>> - time_t t;
>> - errcode_t retval = 0;
>> -
>> if (check_fs_open(argv[0]))
>> return;
>> -
>> - sb = current_fs->super;
>> - if (sb->s_mmp_block <= sb->s_first_data_block ||
>> - sb->s_mmp_block >= ext2fs_blocks_count(sb)) {
>> - com_err(argv[0], EXT2_ET_MMP_BAD_BLOCK, "while dumping it.\n");
>> - return;
>> - }
>> -
>> - if (current_fs->mmp_buf == NULL) {
>> - retval = ext2fs_get_mem(current_fs->blocksize,
>> - ¤t_fs->mmp_buf);
>> - if (retval) {
>> - com_err(argv[0], retval, "allocating MMP buffer.\n");
>> - return;
>> - }
>> - }
>> -
>> - mmp_s = current_fs->mmp_buf;
>> -
>> - retval = ext2fs_mmp_read(current_fs, current_fs->super->s_mmp_block,
>> - current_fs->mmp_buf);
>> - if (retval) {
>> - com_err(argv[0], retval, "reading MMP block.\n");
>> - return;
>> - }
>> -
>> - t = mmp_s->mmp_time;
>> - fprintf(stdout, "block_number: %llu\n", current_fs->super->s_mmp_block);
>> - fprintf(stdout, "update_interval: %d\n",
>> - current_fs->super->s_mmp_update_interval);
>> - fprintf(stdout, "check_interval: %d\n", mmp_s->mmp_check_interval);
>> - fprintf(stdout, "sequence: %08x\n", mmp_s->mmp_seq);
>> - fprintf(stdout, "time: %lld -- %s", mmp_s->mmp_time, ctime(&t));
>> - fprintf(stdout, "node_name: %s\n", mmp_s->mmp_nodename);
>> - fprintf(stdout, "device_name: %s\n", mmp_s->mmp_bdevname);
>> - fprintf(stdout, "magic: 0x%x\n", mmp_s->mmp_magic);
>> - fprintf(stdout, "checksum: 0x%08x\n", mmp_s->mmp_checksum);
>> -#else
>> - fprintf(stdout, "MMP is unsupported, please recompile with "
>> - "--enable-mmp\n");
>> +#endif
>> + retval = ext2fs_mmp_dump(current_fs);
>> +#if CONFIG_MMP
>> + if (retval)
>> + com_err(argv[0], retval, "while dumping it.\n");
>> #endif
>> }
>>
>> Index: e2fsprogs.git/lib/ext2fs/ext2fs.h
>> ===================================================================
>> --- e2fsprogs.git.orig/lib/ext2fs/ext2fs.h
>> +++ e2fsprogs.git/lib/ext2fs/ext2fs.h
>> @@ -1468,6 +1468,7 @@ errcode_t ext2fs_symlink(ext2_filsys fs,
>> /* mmp.c */
>> errcode_t ext2fs_mmp_read(ext2_filsys fs, blk64_t mmp_blk, void *buf);
>> errcode_t ext2fs_mmp_write(ext2_filsys fs, blk64_t mmp_blk, void *buf);
>> +errcode_t ext2fs_mmp_dump(ext2_filsys fs);
>> errcode_t ext2fs_mmp_clear(ext2_filsys fs);
>> errcode_t ext2fs_mmp_init(ext2_filsys fs);
>> errcode_t ext2fs_mmp_start(ext2_filsys fs);
>> Index: e2fsprogs.git/lib/ext2fs/mmp.c
>> ===================================================================
>> --- e2fsprogs.git.orig/lib/ext2fs/mmp.c
>> +++ e2fsprogs.git/lib/ext2fs/mmp.c
>> @@ -19,7 +19,7 @@
>> #include <unistd.h>
>> #endif
>> #include <sys/time.h>
>> -
>> +#include <time.h>
>> #include <sys/types.h>
>> #include <sys/stat.h>
>> #include <fcntl.h>
>> @@ -259,6 +259,54 @@ out:
>> #endif
>> }
>>
>> +errcode_t ext2fs_mmp_dump(ext2_filsys fs)
>> +{
>> +#ifdef CONFIG_MMP
>> + struct ext2_super_block *sb;
>> + struct mmp_struct *mmp_s;
>> + time_t t;
>> + errcode_t retval = 0;
>> +
>> + sb = fs->super;
>> + if (sb->s_mmp_block <= sb->s_first_data_block ||
>> + sb->s_mmp_block >= ext2fs_blocks_count(sb)) {
>> + return EXT2_ET_MMP_BAD_BLOCK;
>> + }
>> +
>> + if (fs->mmp_buf == NULL) {
>> + retval = ext2fs_get_mem(fs->blocksize,
>> + &fs->mmp_buf);
>> + if (retval)
>> + return retval;
>> + }
>> +
>> + mmp_s = fs->mmp_buf;
>> +
>> + retval = ext2fs_mmp_read(fs, fs->super->s_mmp_block,
>> + fs->mmp_buf);
>> + if (retval)
>> + return retval;
>> +
>> + t = mmp_s->mmp_time;
>> + fprintf(stdout, "block_number: %llu\n", fs->super->s_mmp_block);
>> + fprintf(stdout, "update_interval: %d\n",
>> + fs->super->s_mmp_update_interval);
>> + fprintf(stdout, "check_interval: %d\n", mmp_s->mmp_check_interval);
>> + fprintf(stdout, "sequence: %08x\n", mmp_s->mmp_seq);
>> + fprintf(stdout, "time: %lld -- %s", mmp_s->mmp_time, ctime(&t));
>> + fprintf(stdout, "node_name: %s\n", mmp_s->mmp_nodename);
>> + fprintf(stdout, "device_name: %s\n", mmp_s->mmp_bdevname);
>> + fprintf(stdout, "magic: 0x%x\n", mmp_s->mmp_magic);
>> + fprintf(stdout, "checksum: 0x%08x\n", mmp_s->mmp_checksum);
>> +
>> + return 0;
>> +#else
>> + fprintf(stdout, "MMP is unsupported, please recompile with "
>> + "--enable-mmp\n");
>> + return EXT2_ET_OP_NOT_SUPPORTED;
>
> I wonder, maybe this function should simply return the error code and let the
> caller decide if it wants to print out an error? (And, maybe do that on
> stderr?)
>
> <shrug> It's a matter of taste, though I'd rather my error messages show up
> on stderr.
>
> --D
>> +#endif
>> +}
>> +
>> /*
>> * Make sure that the fs is not mounted or being fsck'ed while opening the fs.
>> */
--
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