feat: add initial (and experimental) support for ZFS

configure.ac

@@ -37,6 +37,7 @@ AC_PATH_PROG([LVSBIN], [lvs], [/sbin/lvs])
 AC_PATH_PROG([LVCHANGEBIN], [lvchange], [/sbin/lvchange])
 AC_PATH_PROG([LVMBIN], [lvm], [/sbin/lvm])
 AC_PATH_PROG([LVRENAMEBIN], [lvrename], [/sbin/lvrename])
+AC_PATH_PROG([ZFSBIN], [zfs], [/sbin/zfs])
 
 AC_DEFINE_UNQUOTED([CHSNAPBIN], ["$CHSNAPBIN"], [Path of chsnap program.])
 AC_DEFINE_UNQUOTED([CPBIN], ["$CPBIN"], [Path of cp program.])
@@ -50,6 +51,7 @@ AC_DEFINE_UNQUOTED([LVSBIN], ["$LVSBIN"], [Path of lvs program.])
 AC_DEFINE_UNQUOTED([LVCHANGEBIN], ["$LVCHANGEBIN"], [Path of lvchange program.])
 AC_DEFINE_UNQUOTED([LVMBIN], ["$LVMBIN"], [Path of lvm program.])
 AC_DEFINE_UNQUOTED([LVRENAMEBIN], ["$LVRENAMEBIN"], [Path of lvrename program.])
+AC_DEFINE_UNQUOTED([ZFSBIN], ["$ZFSBIN"], [Path of zfs program.])
 
 dnl Automake 1.11 enables silent compilation
 dnl Disable it by "configure --disable-silent-rules" or "make V=1"
@@ -115,7 +117,16 @@ if test "x$with_lvm" = "xyes"; then
 	AC_DEFINE(ENABLE_LVM, 1, [Enable LVM thin-provisioned snapshots support])
 fi
 
-if test "x$with_btrfs" != "xyes" -a "x$with_lvm" != "xyes" -a "x$with_ext4" != "xyes"; then
+AC_ARG_ENABLE([zfs], AC_HELP_STRING([--disable-zfs],[Disable Zfs internal snapshots support]),
+		[with_zfs=$enableval],[with_zfs=yes])
+
+AM_CONDITIONAL(ENABLE_ZFS, [test "x$with_zfs" = "xyes"])
+
+if test "x$with_zfs" = "xyes"; then
+	AC_DEFINE(ENABLE_ZFS, 1, [Enable Zfs internal snapshots support])
+fi
+
+if test "x$with_btrfs" != "xyes" -a "x$with_lvm" != "xyes" -a "x$with_ext4" != "xyes" -a "x$with_zfs" != "xyes"; then
 	AC_MSG_ERROR([You have to enable at least one snapshot type (remove some --disable-xxx parameter)])
 fi
 

snapper/Filesystem.cc

@@ -45,6 +45,9 @@
 #ifdef ENABLE_LVM
 #include "snapper/Lvm.h"
 #endif
+#ifdef ENABLE_ZFS
+#include "snapper/Zfs.h"
+#endif
 #include "snapper/Snapper.h"
 #include "snapper/SnapperTmpl.h"
 #include "snapper/SnapperDefines.h"
@@ -106,6 +109,9 @@ namespace snapper
 #endif
 #ifdef ENABLE_LVM
 		&Lvm::create,
+#endif
+#ifdef ENABLE_ZFS
+		&Zfs::create,
 #endif
 		NULL
 	};

snapper/Makefile.am

@@ -51,6 +51,12 @@ libsnapper_la_SOURCES +=				\
 	LvmCache.cc		LvmCache.h
 endif
 
+if ENABLE_ZFS
+libsnapper_la_SOURCES +=				\
+	Zfs.cc			Zfs.h		        \
+	ZfsUtils.cc		ZfsUtils.h
+endif
+
 if ENABLE_ROLLBACK
 libsnapper_la_SOURCES +=				\
 	MntTable.cc		MntTable.h

snapper/Snapper.cc

@@ -48,6 +48,7 @@
 #include "snapper/Hooks.h"
 #include "snapper/Btrfs.h"
 #include "snapper/BtrfsUtils.h"
+#include "snapper/ZfsUtils.h"
 #ifdef ENABLE_SELINUX
 #include "snapper/Selinux.h"
 #include "snapper/Regex.h"
@@ -1012,6 +1013,11 @@ namespace snapper
 #endif
 	    "ext4,"
 
+#ifndef ENABLE_ZFS
+	    "no-"
+#endif
+	    "zfs,"
+
 #ifndef ENABLE_XATTRS
 	    "no-"
 #endif

snapper/Zfs.cc

@@ -0,0 +1,198 @@
+/*
+ * Copyright (c) [2019] SUSE LLC
+ *
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU General Public License 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 for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, contact Novell, Inc.
+ *
+ * To contact Novell about this file by physical or electronic mail, you may
+ * find current contact information at www.novell.com.
+ */
+
+#include "config.h"
+
+#include <asm/types.h>
+#include <boost/algorithm/string.hpp>
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "snapper/Log.h"
+#include "snapper/Filesystem.h"
+#include "snapper/Zfs.h"
+#include "snapper/Snapper.h"
+#include "snapper/SnapperTmpl.h"
+#include "snapper/SystemCmd.h"
+#include "snapper/SnapperDefines.h"
+
+
+namespace snapper
+{
+    Filesystem*
+    Zfs::create(const string& fstype, const string& subvolume, const string& root_prefix)
+    {
+        if (fstype == "zfs")
+            return new Zfs(subvolume, root_prefix);
+
+        return NULL;
+    }
+
+    Zfs::Zfs(const string& subvolume, const string& root_prefix) : Filesystem(subvolume, root_prefix)
+    {
+        if (access(ZFSBIN, X_OK) != 0)
+            SN_THROW(ProgramNotInstalledException(ZFSBIN " is not installed"));
+
+        bool found = false;
+        MtabData mtab_data;
+
+        if (!getMtabData(subvolume, found, mtab_data))
+        {
+            y2err("can't get mtab data for " + subvolume);
+            SN_THROW(InvalidConfigException());
+        }
+
+        if (!found)
+        {
+            y2err("filesystem not mounted");
+            SN_THROW(InvalidConfigException());
+        }
+
+        zfs_volume_name = mtab_data.device;
+        zfs_snapshot_volume_name = zfs_volume_name + "/.snapshots";
+    }
+
+    string
+    Zfs::snapshotDir(unsigned int num) const
+    {
+        return (subvolume == "/" ? "" : subvolume) + "/.snapshots/" + decString(num) + "/snapshot";
+    }
+
+    void
+    Zfs::createConfig() const
+    {
+        create_volume(zfs_snapshot_volume_name, true);
+    }
+
+    void
+    Zfs::deleteConfig() const
+    {
+        delete_volume(zfs_snapshot_volume_name);
+    }
+
+    SDir
+    Zfs::openInfosDir() const
+    {
+        SDir subvolume_dir = openSubvolumeDir();
+
+        if (subvolume_dir.mkdir(".snapshots", 0700) != 0 && errno != EEXIST)
+        {
+            y2err("mkdir failed errno:" << errno << " (" << strerror(errno) << ")");
+            SN_THROW(CreateConfigFailedException("mkdir failed"));
+        }
+
+        SDir infos_dir(subvolume_dir, ".snapshots");
+
+        struct stat stat;
+
+        if (infos_dir.stat(&stat) != 0)
+        {
+            SN_THROW(IOErrorException("failed to stat " + infos_dir.fullname()));
+        }
+
+        if (stat.st_uid != 0)
+        {
+            SN_THROW(IOErrorException(".snapshots must have owner root"));
+        }
+
+        if (stat.st_gid != 0 && stat.st_mode & S_IWGRP)
+        {
+            SN_THROW(IOErrorException(".snapshots must have group root or must not be group-writable"));
+        }
+
+        if (stat.st_mode & S_IWOTH)
+        {
+            SN_THROW(IOErrorException(".snapshots must not be world-writable"));
+        }
+
+        return infos_dir;
+    }
+
+    SDir
+    Zfs::openSnapshotDir(unsigned int num) const
+    {
+        SDir info_dir = openInfoDir(num);
+        SDir snapshot_dir(info_dir, "snapshot");
+
+        return snapshot_dir;
+    }
+
+    void
+    Zfs::mountSnapshot(unsigned int num) const
+    {
+    }
+
+    void
+    Zfs::umountSnapshot(unsigned int num) const
+    {
+    }
+
+    /* ZFS snapshots are always mounted int the `.zfs` directory, they are also
+     * automatically symlinked by snapper in the datasets' `.snapshot`
+     * directory.
+     */
+    bool
+    Zfs::isSnapshotMounted(unsigned int num) const
+    {
+        return true;
+    }
+
+    void
+    Zfs::createSnapshot(unsigned int num, unsigned int num_parent, bool read_only, bool quota, bool empty) const
+    {
+        if (num_parent != 0 || !read_only || quota || empty)
+            SN_THROW(UnsupportedException());
+
+        create_snapshot(zfs_volume_name, decString(num));
+        symlink("../../.zfs/snapshot/" + decString(num), snapshotDir(num));
+    }
+
+    void
+    Zfs::deleteSnapshot(unsigned int num) const
+    {
+        unlink(snapshotDir(num).c_str());
+        delete_snapshot(zfs_volume_name, decString(num));
+    }
+
+    bool
+    Zfs::checkSnapshot(unsigned int num) const
+    {
+        return snapshot_exists(zfs_volume_name, decString(num));
+    }
+
+    /* ZFS does not support mutable snapshots.
+     */
+    bool
+    Zfs::isSnapshotReadOnly(unsigned int num) const
+    {
+        return true;
+    }
+
+    void
+    Zfs::sync() const
+    {
+    }
+}

snapper/Zfs.h

@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) [2019] SUSE LLC
+ *
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU General Public License 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 for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, contact Novell, Inc.
+ *
+ * To contact Novell about this file by physical or electronic mail, you may
+ * find current contact information at www.novell.com.
+ */
+
+
+#ifndef SNAPPER_ZFS_H
+#define SNAPPER_ZFS_H
+
+
+#include "snapper/Filesystem.h"
+#include "snapper/ZfsUtils.h"
+
+
+namespace snapper
+{
+    using namespace ZfsUtils;
+
+    class Zfs : public Filesystem
+    {
+    public:
+        static Filesystem* create(const string& fstype, const string& subvolume, const string& root_prefix);
+
+        Zfs(const string& subvolume, const string& root_prefix);
+
+        virtual string fstype() const
+        {
+            return "zfs";
+        }
+
+        virtual string snapshotDir(unsigned int num) const;
+
+        virtual void createConfig() const;
+        virtual void deleteConfig() const;
+
+        virtual SDir openInfosDir() const;
+
+        virtual SDir openSnapshotDir(unsigned int num) const;
+
+        virtual void mountSnapshot(unsigned int num) const;
+        virtual void umountSnapshot(unsigned int num) const;
+        virtual bool isSnapshotMounted(unsigned int num) const;
+
+        virtual void createSnapshot(unsigned int num, unsigned int num_parent, bool read_only, bool quota, bool empty) const;
+        virtual void deleteSnapshot(unsigned int num) const;
+        virtual bool checkSnapshot(unsigned int num) const;
+
+        virtual bool isSnapshotReadOnly(unsigned int num) const;
+
+        virtual void sync() const;
+
+    private:
+        string zfs_volume_name;
+        string zfs_snapshot_volume_name;
+    };
+}
+
+#endif