[xfsprogs PATCH v2 3/3] xfs_io: add a new 'log_writes' command

Ross Zwisler
2017-12-05T23:57:09Z

Add a new 'log_writes' command to xfs_io so that we can add dm-log-writes
log marks. It's helpful to allow users of xfs_io to adds these marks from
within xfs_io instead of waiting until after xfs_io exits because then they
are able to replay the dm-log-writes log up to immediately after another
xfs_io operation such as mwrite. This isolates the log replay from other
operations that happen as part of xfs_io exiting (file handles being
closed, mmaps being torn down, etc.). This also allows users to insert
multiple marks between different xfs_io commands.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Suggested-by: Dave Chinner <david@fromorbit.com>
---
configure.ac | 1 +
debian/control | 2 +-
include/builddefs.in | 2 +
io/Makefile | 6 +++
io/init.c | 1 +
io/io.h | 6 +++
io/log_writes.c | 101 ++++++++++++++++++++++++++++++++++++++++++++++++
m4/Makefile | 1 +
m4/package_devmapper.m4 | 11 ++++++
man/man8/xfs_io.8 | 23 ++++++++++-
10 files changed, 152 insertions(+), 2 deletions(-)
create mode 100644 io/log_writes.c
create mode 100644 m4/package_devmapper.m4

diff --git a/configure.ac b/configure.ac
index f3325aa0..f83d5817 100644
--- a/configure.ac
+++ b/configure.ac
@@ -164,6 +164,7 @@ AC_NEED_INTERNAL_FSXATTR
AC_HAVE_GETFSMAP
AC_HAVE_STATFS_FLAGS
AC_HAVE_MAP_SYNC
+AC_HAVE_DEVMAPPER

if test "$enable_blkid" = yes; then
AC_HAVE_BLKID_TOPO
diff --git a/debian/control b/debian/control
index ad816622..5c26e3d7 100644
--- a/debian/control
+++ b/debian/control
@@ -3,7 +3,7 @@ Section: admin
Priority: optional
Maintainer: XFS Development Team <linux-xfs@vger.kernel.org>
Uploaders: Nathan Scott <nathans@debian.org>, Anibal Monsalve Salazar <anibal@debian.org>
-Build-Depends: uuid-dev, dh-autoreconf, debhelper (>= 5), gettext, libtool, libreadline-gplv2-dev | libreadline5-dev, libblkid-dev (>= 2.17), linux-libc-dev
+Build-Depends: uuid-dev, dh-autoreconf, debhelper (>= 5), gettext, libtool, libreadline-gplv2-dev | libreadline5-dev, libblkid-dev (>= 2.17), linux-libc-dev, libdevmapper-dev
Standards-Version: 3.9.1
Homepage: http://xfs.org/

diff --git a/include/builddefs.in b/include/builddefs.in
index 126f7e95..66bdbfa2 100644
--- a/include/builddefs.in
+++ b/include/builddefs.in
@@ -35,6 +35,7 @@ LIBTERMCAP = @libtermcap@
LIBEDITLINE = @libeditline@
LIBREADLINE = @libreadline@
LIBBLKID = @libblkid@
+LIBDEVMAPPER = @libdevmapper@
LIBXFS = $(TOPDIR)/libxfs/libxfs.la
LIBXCMD = $(TOPDIR)/libxcmd/libxcmd.la
LIBXLOG = $(TOPDIR)/libxlog/libxlog.la
@@ -116,6 +117,7 @@ NEED_INTERNAL_FSXATTR = @need_internal_fsxattr@
HAVE_GETFSMAP = @have_getfsmap@
HAVE_STATFS_FLAGS = @have_statfs_flags@
HAVE_MAP_SYNC = @have_map_sync@
+HAVE_DEVMAPPER = @have_devmapper@

GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall
# -Wbitwise -Wno-transparent-union -Wno-old-initializer -Wno-decl
diff --git a/io/Makefile b/io/Makefile
index 2987ee11..b7585a1b 100644
--- a/io/Makefile
+++ b/io/Makefile
@@ -107,6 +107,12 @@ ifeq ($(HAVE_MAP_SYNC),yes)
LCFLAGS += -DHAVE_MAP_SYNC
endif

+ifeq ($(HAVE_DEVMAPPER),yes)
+CFILES += log_writes.c
+LLDLIBS += $(LIBDEVMAPPER)
+LCFLAGS += -DHAVE_DEVMAPPER
+endif
+
# On linux we get fsmap from the system or define it ourselves
# so include this based on platform type. If this reverts to only
# the autoconf check w/o local definition, change to testing HAVE_GETFSMAP
diff --git a/io/init.c b/io/init.c
index 20d5f80d..34d87b5f 100644
--- a/io/init.c
+++ b/io/init.c
@@ -72,6 +72,7 @@ init_commands(void)
help_init();
imap_init();
inject_init();
+ log_writes_init();
madvise_init();
mincore_init();
mmap_init();
diff --git a/io/io.h b/io/io.h
index 8b2753b3..9349cc75 100644
--- a/io/io.h
+++ b/io/io.h
@@ -186,3 +186,9 @@ extern void fsmap_init(void);
#else
# define fsmap_init() do { } while (0)
#endif
+
+#ifdef HAVE_DEVMAPPER
+extern void log_writes_init(void);
+#else
+#define log_writes_init() do { } while (0)
+#endif
diff --git a/io/log_writes.c b/io/log_writes.c
new file mode 100644
index 00000000..37c0024f
--- /dev/null
+++ b/io/log_writes.c
@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2017 Intel Corporation.
+ * All Rights Reserved.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it would 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 for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "platform_defs.h"
+#include <libdevmapper.h>
+#include "command.h"
+#include "init.h"
+
+static cmdinfo_t log_writes_cmd;
+
+static void
+mark_log(const char *device, const char *mark)
+{
+ struct dm_task *dmt;
+ const int size = 80;
+ char message[size];
+ int len;
+
+ len = snprintf(message, size, "mark %s", mark);
+ if (len >= size) {
+ printf("mark '%s' is too long\n", mark);
+ return;
+ }
+
+ if (!(dmt = dm_task_create(DM_DEVICE_TARGET_MSG)))
+ return;
+
+ if (!dm_task_set_name(dmt, device))
+ goto out;
+
+ if (!dm_task_set_sector(dmt, 0))
+ goto out;
+
+ if (!dm_task_set_message(dmt, message))
+ goto out;
+
+ dm_task_run(dmt);
+out:
+ dm_task_destroy(dmt);
+}
+
+static int
+log_writes_f(
+ int argc,
+ char **argv)
+{
+ const char *device = NULL;
+ const char *mark = NULL;
+ int c;
+
+ while ((c = getopt(argc, argv, "d:m:")) != EOF) {
+ switch (c) {
+ case 'd':
+ device = optarg;
+ break;
+ case 'm':
+ mark = optarg;
+ break;
+ default:
+ return command_usage(&log_writes_cmd);
+ }
+ }
+
+ if (device == NULL || mark == NULL)
+ return command_usage(&log_writes_cmd);
+
+ mark_log(device, mark);
+ return 0;
+}
+
+void
+log_writes_init(void)
+{
+ log_writes_cmd.name = "log_writes";
+ log_writes_cmd.altname = "lw";
+ log_writes_cmd.cfunc = log_writes_f;
+ log_writes_cmd.flags = CMD_NOMAP_OK | CMD_NOFILE_OK | CMD_FOREIGN_OK
+ | CMD_FLAG_ONESHOT;
+ log_writes_cmd.argmin = 0;
+ log_writes_cmd.argmax = -1;
+ log_writes_cmd.args = _("-d device -m mark");
+ log_writes_cmd.oneline =
+ _("create mark in the dm-log-writes log specified by <device>");
+
+ add_command(&log_writes_cmd);
+}
diff --git a/m4/Makefile b/m4/Makefile
index 4706121b..77f2edda 100644
--- a/m4/Makefile
+++ b/m4/Makefile
@@ -15,6 +15,7 @@ CONFIGURE = \
LSRCFILES = \
manual_format.m4 \
package_blkid.m4 \
+ package_devmapper.m4 \
package_globals.m4 \
package_libcdev.m4 \
package_pthread.m4 \
diff --git a/m4/package_devmapper.m4 b/m4/package_devmapper.m4
new file mode 100644
index 00000000..821f283c
--- /dev/null
+++ b/m4/package_devmapper.m4
@@ -0,0 +1,11 @@
+#
+# See if libdevmapper is available on the system.
+#
+AC_DEFUN([AC_HAVE_DEVMAPPER],
+[ AC_SEARCH_LIBS([dm_task_create], [devmapper],
+ libdevmapper="-ldevmapper"
+ have_devmapper=yes,
+ have_devmapper=no,)
+ AC_SUBST(have_devmapper)
+ AC_SUBST(libdevmapper)
+])
diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
index 1693f7f1..4fce6d39 100644
--- a/man/man8/xfs_io.8
+++ b/man/man8/xfs_io.8
@@ -1123,7 +1123,27 @@ version of policy structure (numeric)
.BR get_encpolicy
On filesystems that support encryption, display the encryption policy of the
current file.
+.RE
+.PD
+.TP
+.BI "log_writes \-d " device " \-m " mark
+Create a mark named
+.I mark
+in the dm-log-writes log specified by
+.I device.
+This is intended to be equivalent to the shell command:

+.B dmsetup message
+.I device
+.B 0 mark
+.I mark
+.PD
+.RE
+.TP
+.B lw
+See the
+.B log_writes
+command.
.SH SEE ALSO
.BR mkfs.xfs (8),
.BR xfsctl (3),
@@ -1141,4 +1161,5 @@ current file.
.BR open (2),
.BR pread (2),
.BR pwrite (2),
-.BR readdir (3).
+.BR readdir (3),
+.BR dmsetup (8).
--
2.14.3