[cache_writeback] stub cache_writeback

Makefile.in

@@ -41,6 +41,7 @@ SOURCE=\
 	caching/cache_metadata_size.cc \
 	caching/cache_repair.cc \
 	caching/cache_restore.cc \
+	caching/cache_writeback.cc \
 	caching/commands.cc \
 	caching/hint_array.cc \
 	caching/mapping_array.cc \
@@ -216,6 +217,7 @@ install: bin/pdata_tools
 	ln -s -f pdata_tools $(BINDIR)/cache_metadata_size
 	ln -s -f pdata_tools $(BINDIR)/cache_repair
 	ln -s -f pdata_tools $(BINDIR)/cache_restore
+	ln -s -f pdata_tools $(BINDIR)/cache_writeback
 	ln -s -f pdata_tools $(BINDIR)/thin_check
 	ln -s -f pdata_tools $(BINDIR)/thin_delta
 	ln -s -f pdata_tools $(BINDIR)/thin_dump
@@ -235,6 +237,7 @@ install: bin/pdata_tools
 	$(INSTALL_DATA) man8/cache_dump.8 $(MANPATH)/man8
 	$(INSTALL_DATA) man8/cache_repair.8 $(MANPATH)/man8
 	$(INSTALL_DATA) man8/cache_restore.8 $(MANPATH)/man8
+	$(INSTALL_DATA) man8/cache_writeback.8 $(MANPATH)/man8
 	$(INSTALL_DATA) man8/thin_check.8 $(MANPATH)/man8
 	$(INSTALL_DATA) man8/thin_delta.8 $(MANPATH)/man8
 	$(INSTALL_DATA) man8/thin_dump.8 $(MANPATH)/man8

caching/cache_writeback.cc

@@ -0,0 +1,122 @@
+#ifndef CACHING_CACHE_WRITEBACK_H
+#define CACHING_CACHE_WRITEBACK_H
+
+#include "caching/commands.h"
+#include "version.h"
+
+#include <boost/optional.hpp>
+#include <getopt.h>
+#include <string>
+
+using namespace caching;
+using namespace boost;
+using namespace std;
+
+//----------------------------------------------------------------
+
+namespace {
+	struct flags {
+		using maybe_string = boost::optional<string>;
+
+		maybe_string metadata_dev;
+		maybe_string origin_dev;
+		maybe_string fast_dev;
+	};
+
+	int writeback(flags const &f) {
+		return 1;
+	}
+}
+
+//----------------------------------------------------------------
+
+cache_writeback_cmd::cache_writeback_cmd()
+	: command("cache_writeback")
+{
+}
+
+void
+cache_writeback_cmd::usage(std::ostream &out) const
+{
+	out << "Usage: " << get_name() << " [options]\n"
+	    << "\t\t--metadata-device <dev>\n"
+	    << "\t\t--origin-device <dev>\n"
+	    << "\t\t--fast-device <dev>\n"
+	    << "Options:\n"
+	    << "  {-h|--help}\n"
+	    << "  {-V|--version}" << endl;
+}
+
+int
+cache_writeback_cmd::run(int argc, char **argv)
+{
+	int c;
+	flags fs;
+	char const *short_opts = "hV";
+	option const long_opts[] = {
+		{ "metadata-device", required_argument, NULL, 0 },
+		{ "origin-device", required_argument, NULL, 1 },
+		{ "fast-device", required_argument, NULL, 2 },
+		{ "help", no_argument, NULL, 'h'},
+		{ "version", no_argument, NULL, 'V'},
+		{ NULL, no_argument, NULL, 0 }
+	};
+
+	while ((c = getopt_long(argc, argv, short_opts, long_opts, NULL)) != -1) {
+		switch(c) {
+		case 0:
+			fs.metadata_dev = optarg;
+			break;
+
+		case 1:
+			fs.origin_dev = optarg;
+			break;
+
+		case 2:
+			fs.fast_dev = optarg;
+			break;
+
+		case 'h':
+			usage(cout);
+			return 0;
+
+		case 'V':
+			cout << THIN_PROVISIONING_TOOLS_VERSION << endl;
+			return 0;
+
+		default:
+			usage(cerr);
+			return 1;
+		}
+	}
+
+	if (argc != optind) {
+		usage(cerr);
+		return 1;
+	}
+
+        if (!fs.metadata_dev) {
+		cerr << "No metadata device provided.\n\n";
+		usage(cerr);
+		return 1;
+	}
+
+	if (!fs.origin_dev) {
+		cerr << "No origin device provided.\n\n";
+		usage(cerr);
+		return 1;
+	}
+
+	if (!fs.fast_dev) {
+		cerr << "No fast device provided.\n\n";
+		usage(cerr);
+		return 1;
+	}
+
+	return writeback(fs);
+
+}
+
+//----------------------------------------------------------------
+
+#endif

caching/commands.cc

@@ -13,6 +13,7 @@ caching::register_cache_commands(application &app)
 	app.add_cmd(command::ptr(new cache_metadata_size_cmd));
 	app.add_cmd(command::ptr(new cache_restore_cmd));
 	app.add_cmd(command::ptr(new cache_repair_cmd));
+	app.add_cmd(command::ptr(new cache_writeback_cmd));
 }
 
 //----------------------------------------------------------------

caching/commands.h

@@ -63,6 +63,13 @@ namespace caching {
 		virtual int run(int argc, char **argv);
 	};
 
+	class cache_writeback_cmd : public base::command {
+	public:
+		cache_writeback_cmd();
+		virtual void usage(std::ostream &out) const;
+		virtual int run(int argc, char **argv);
+	};
+
 	void register_cache_commands(base::application &app);
 }
 

man8/cache_writeback.8

@@ -0,0 +1,53 @@
+.TH CACHE_WRITEBACK 8 "Thin Provisioning Tools" "Red Hat, Inc." \" -*- nroff -*-
+.SH NAME
+cache_writeback \- writeback dirty blocks to the origin device.
+
+.SH SYNOPSIS
+.B cache_writeback
+.RB [ options ]
+.RB --metadata-device
+.I {device|file}
+.RB --origin-device
+.I {device|file}
+.RB --fast-device
+.I {device|file}
+
+.SH DESCRIPTION
+.B cache_writeback
+
+An offline tool that writesback dirty data to the data device
+(origin).  Intended for use in recovery scenarios when the SSD is
+giving IO errors.
+
+This tool cannot be run on a live cache.
+
+.SH OPTIONS
+
+.IP "\fB\\-\-metadata\-device\fP \fI{device|file}\fP"
+Location of cache metadata.
+
+.IP "\fB\-\-origin\-device\fP \fI{device|file}\fP"
+Slow device being cached.
+
+.IP "\fB\-\-fast\-device\fP \fI{device|file}\fP"
+Fast device containing the data that needs to be written back.
+
+.IP "\fB\-\-skip\-metadata\-update\fP"
+Do not update the metadata to clear the dirty flags for written back
+data.  You may not want to do this if you're decommissioning the
+cache.
+
+.IP "\fB\-h, \-\-help\fP"
+Print help and exit.
+
+.IP "\fB\-V, \-\-version\fP"
+Output version information and exit.
+
+.SH SEE ALSO
+.B cache_dump(8)
+.B cache_check(8)
+.B cache_repair(8)
+.B cache_restore(8)
+
+.SH AUTHOR
+Joe Thornber <ejt@redhat.com>

thin-provisioning/commands.h

@@ -77,17 +77,17 @@ namespace thin_provisioning {
 		virtual int run(int argc, char **argv);
 	};
 
-#ifdef DEV_TOOLS
+	class thin_trim_cmd : public base::command {
-	class thin_scan_cmd : public base::command {
 	public:
-		thin_scan_cmd();
+		thin_trim_cmd();
 		virtual void usage(std::ostream &out) const;
 		virtual int run(int argc, char **argv);
 	};
 
-	class thin_trim_cmd : public base::command {
+#ifdef DEV_TOOLS
+	class thin_scan_cmd : public base::command {
 	public:
-		thin_trim_cmd();
+		thin_scan_cmd();
 		virtual void usage(std::ostream &out) const;
 		virtual int run(int argc, char **argv);
 	};