From: Ondrej Kozina <okozina@redhat.com>
Date: Fri, 9 Aug 2013 10:00:43 +0000 (+0200)
Subject: - make snapper capable handling inactive lvm snapshots
X-Git-Tag: v0.1.7~8^2~10
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=f800175bfdc4d30f201e5382f942aa7d59e57e27;p=thirdparty%2Fsnapper.git

- make snapper capable handling inactive lvm snapshots
---

diff --git a/configure.ac b/configure.ac
index 51b07be9..b6c4f222 100644
--- a/configure.ac
+++ b/configure.ac
@@ -35,6 +35,7 @@ AC_PATH_PROG([CHATTRBIN], [chattr], [/usr/bin/chattr])
 AC_PATH_PROG([LVCREATEBIN], [lvcreate], [/sbin/lvcreate])
 AC_PATH_PROG([LVREMOVEBIN], [lvremove], [/sbin/lvremove])
 AC_PATH_PROG([LVSBIN], [lvs], [/sbin/lvs])
+AC_PATH_PROG([LVCHANGEBIN], [lvchange], [/sbin/lvchange])
 
 AC_DEFINE_UNQUOTED([CHSNAPBIN], ["$CHSNAPBIN"], [Path of chsnap program.])
 AC_DEFINE_UNQUOTED([CPBIN], ["$CPBIN"], [Path of cp program.])
@@ -45,6 +46,7 @@ AC_DEFINE_UNQUOTED([CHATTRBIN], ["$CHATTRBIN"], [Path of chattr program.])
 AC_DEFINE_UNQUOTED([LVCREATEBIN], ["$LVCREATEBIN"], [Path of lvcreate program.])
 AC_DEFINE_UNQUOTED([LVREMOVEBIN], ["$LVREMOVEBIN"], [Path of lvremove program.])
 AC_DEFINE_UNQUOTED([LVSBIN], ["$LVSBIN"], [Path of lvs program.])
+AC_DEFINE_UNQUOTED([LVCHANGEBIN], ["$LVCHANGEBIN"], [Path of lvchange program.])
 
 dnl Automake 1.11 enables silent compilation
 dnl Disable it by "configure --disable-silent-rules" or "make V=1"
diff --git a/snapper/Lvm.cc b/snapper/Lvm.cc
index 930c6688..dc061cb8 100644
--- a/snapper/Lvm.cc
+++ b/snapper/Lvm.cc
@@ -229,6 +229,16 @@ namespace snapper
 	if (isSnapshotMounted(num))
 	    return;
 
+	try
+	{
+	    activateSnapshot(vg_name, snapshotLvName(num));
+	}
+	catch (const LvmActivationException& e)
+	{
+	    y2err("Couldn't mount snapshot " << num);
+	    throw MountSnapshotFailedException();
+	}
+
 	SDir snapshot_dir = openSnapshotDir(num);
 
 	if (!mount(getDevice(num), snapshot_dir, mount_type, mount_options))
@@ -246,6 +256,15 @@ namespace snapper
 
 	if (!umount(info_dir, "snapshot"))
 	    throw UmountSnapshotFailedException();
+
+	try
+	{
+	    deactivateSnapshot(vg_name, snapshotLvName(num));
+	}
+	catch (const LvmDeactivatationException& e)
+	{
+	    y2war("Snapshot #" << num << "deactivation failed");
+	}
     }
 
 
@@ -254,7 +273,8 @@ namespace snapper
     {
 	struct stat stat;
 	int r1 = ::stat(getDevice(num).c_str(), &stat);
-	return r1 == 0 && S_ISBLK(stat.st_mode);
+
+	return (r1 == 0 && S_ISBLK(stat.st_mode)) || detectInactiveSnapshot(vg_name, snapshotLvName(num));
     }
 
 
@@ -295,4 +315,42 @@ namespace snapper
 	    boost::replace_all_copy(snapshotLvName(num), "-", "--");
     }
 
+
+    void
+    Lvm::activateSnapshot(const string& vg_name, const string& lv_name) const
+    {
+	SystemCmd cmd(LVCHANGEBIN " -ay -K " + quote(vg_name + "/" + lv_name));
+	switch (cmd.retcode())
+	{
+	    case 0:
+		break;
+	    case EINVALID_CMD_LINE:
+	    {
+		SystemCmd retry_cmd(LVCHANGEBIN " -ay " + quote(vg_name + "/" + lv_name));
+		if (retry_cmd.retcode() == 0)
+		    break;
+	    }
+	    default:
+		y2err("Couldn't activate snapshot " << vg_name << "/" << lv_name);
+		throw LvmActivationException();
+	}
+    }
+
+
+    void
+    Lvm::deactivateSnapshot(const string& vg_name, const string& lv_name) const
+    {
+	SystemCmd cmd(LVCHANGEBIN " -an " + quote(vg_name + "/" + lv_name));
+	if (cmd.retcode())
+	    throw LvmDeactivatationException();
+    }
+
+
+    bool
+    Lvm::detectInactiveSnapshot(const string& vg_name, const string& lv_name) const
+    {
+	SystemCmd cmd(LVSBIN " " + quote(vg_name + "/" + lv_name));
+	return cmd.retcode() == 0;
+    }
+
 }
diff --git a/snapper/Lvm.h b/snapper/Lvm.h
index a853921b..20aab449 100644
--- a/snapper/Lvm.h
+++ b/snapper/Lvm.h
@@ -23,12 +23,31 @@
 #ifndef SNAPPER_LVM_H
 #define SNAPPER_LVM_H
 
+/*
+ * tools/errors.h from lvm2 source
+ *
+ * consider adding lvm2-devel dep for lvm2 enabled snapper
+ */
+#define EINVALID_CMD_LINE 3
 
 #include "snapper/Filesystem.h"
 
 
 namespace snapper
 {
+    struct LvmActivationException : public std::exception
+    {
+	explicit LvmActivationException() throw() {}
+	virtual const char* what() const throw() { return "lvm snapshot activation exception"; }
+    };
+
+
+    struct LvmDeactivatationException : public std::exception
+    {
+	explicit LvmDeactivatationException() throw() {}
+	virtual const char* what() const throw() { return "lvm snapshot deactivation exception"; }
+    };
+
 
     class Lvm : public Filesystem
     {
@@ -64,6 +83,10 @@ namespace snapper
 
 	bool detectThinVolumeNames(const MtabData& mtab_data);
 
+	void activateSnapshot(const string& vg_name, const string& lv_name) const;
+	void deactivateSnapshot(const string& vg_name, const string& lv_name) const;
+	bool detectInactiveSnapshot(const string& vg_name, const string& lv_name) const;
+
 	string getDevice(unsigned int num) const;
 
 	string vg_name;