Add a new 'log_writes' command to xfs_io so that we can add dm-log-writes
log marks via the external 'dmsetup' executable. 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@xxxxxxxxxxxxxxx>
Suggested-by: Dave Chinner <david@xxxxxxxxxxxxx>
---
io/Makefile | 5 ++--
io/init.c | 1 +
io/io.h | 1 +
io/log_writes.c | 78 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
man/man8/xfs_io.8 | 19 ++++++++++++++
5 files changed, 102 insertions(+), 2 deletions(-)
create mode 100644 io/log_writes.c
diff --git a/io/Makefile b/io/Makefile
index 050d6bd..51b2eae 100644
--- a/io/Makefile
+++ b/io/Makefile
@@ -10,8 +10,9 @@ LSRCFILES = xfs_bmap.sh xfs_freeze.sh xfs_mkfile.sh
HFILES = init.h io.h
CFILES = init.c \
attr.c bmap.c cowextsize.c encrypt.c file.c freeze.c fsync.c \
- getrusage.c imap.c link.c mmap.c open.c parent.c pread.c prealloc.c \
- pwrite.c reflink.c seek.c shutdown.c stat.c sync.c truncate.c utimes.c
+ getrusage.c imap.c link.c log_writes.c mmap.c open.c parent.c pread.c \
+ prealloc.c pwrite.c reflink.c seek.c shutdown.c stat.c sync.c \
+ truncate.c utimes.c
LLDLIBS = $(LIBXCMD) $(LIBHANDLE) $(LIBPTHREAD)
LTDEPENDENCIES = $(LIBXCMD) $(LIBHANDLE)
diff --git a/io/init.c b/io/init.c
index 20d5f80..34d87b5 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 8b2753b..d62034a 100644
--- a/io/io.h
+++ b/io/io.h
@@ -109,6 +109,7 @@ extern void getrusage_init(void);
extern void help_init(void);
extern void imap_init(void);
extern void inject_init(void);
+extern void log_writes_init(void);
extern void mmap_init(void);
extern void open_init(void);
extern void parent_init(void);
diff --git a/io/log_writes.c b/io/log_writes.c
new file mode 100644
index 0000000..bc3952c
--- /dev/null
+++ b/io/log_writes.c
@@ -0,0 +1,78 @@
+/*
+ * 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 "command.h"
+#include "init.h"
+
+static cmdinfo_t log_writes_cmd;
+
+static int
+mark_log(char *device, char *mark)
+{
+ char command[256];
+
+ snprintf(command, 256, "dmsetup message %s 0 mark %s",
+ device, mark);
+
+ return system(command);
+}
+
+static int
+log_writes_f(
+ int argc,
+ char **argv)
+{
+ char *device = NULL;
+ 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);
+
+ return mark_log(device, mark);
+}
+
+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;
+ log_writes_cmd.argmin = 0;
+ log_writes_cmd.argmax = -1;
+ log_writes_cmd.args = _("-d device -m mark");
+ log_writes_cmd.oneline =
+ _("uses dmsetup to interact with the dm-log-writes module");
+
+ add_command(&log_writes_cmd);
+}
diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
index 1693f7f..f18af99 100644
--- a/man/man8/xfs_io.8
+++ b/man/man8/xfs_io.8
@@ -1123,7 +1123,25 @@ 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
+Use
+.B dmsetup
+to interact with the
+.B dm-log-writes
+kernel module. Currently the only operation
+supported is the creation of a mark in the log by executing the shell command:
+.B dmsetup message <device> 0 mark <mark>
+.PD
+.RE
+.TP
+.B lw
+See the
+.B log_writes
+command.
.SH SEE ALSO
.BR mkfs.xfs (8),
.BR xfsctl (3),
@@ -1142,3 +1160,4 @@ current file.
.BR pread (2),
.BR pwrite (2),
.BR readdir (3).
+.BR dmsetup (8).
--
2.9.5
--
To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
