- use ioctl instead of btrfs program

diff --git a/snapper/FileUtils.h b/snapper/FileUtils.h
index ab1e38377742b06016feebea79716d2c6edad50c..1a442927c4764aa9e2912639b0536583c0720a34 100644 (file)
--- a/snapper/FileUtils.h
+++ b/snapper/FileUtils.h
@@ -46,6 +46,8 @@ namespace snapper
        SDir& operator=(const SDir&);
        ~SDir();
 
+       int fd() const { return dirfd; }
+
        string fullname(bool with_base_path = true) const;
        string fullname(const string& name, bool with_base_path = true) const;
 

diff --git a/snapper/Filesystem.cc b/snapper/Filesystem.cc
index aba18c7db8a9612a41255f3dc05f16eaf06b7a16..33986bce5d74a2966c5c198ec21fa5a2e306ded5 100644 (file)
--- a/snapper/Filesystem.cc
+++ b/snapper/Filesystem.cc
@@ -27,6 +27,8 @@
 #include <unistd.h>
 #include <mntent.h>
 #include <fcntl.h>
+#include <sys/ioctl.h>
+#include <asm/types.h>
 
 #include "snapper/Log.h"
 #include "snapper/Filesystem.h"
@@ -36,6 +38,31 @@
 #include "snapper/SnapperDefines.h"
 
 
+#define BTRFS_IOCTL_MAGIC 0x94
+#define BTRFS_PATH_NAME_MAX 4087
+#define BTRFS_SUBVOL_NAME_MAX 4039
+#define BTRFS_SUBVOL_RDONLY (1ULL << 1)
+
+#define BTRFS_IOC_SUBVOL_CREATE _IOW(BTRFS_IOCTL_MAGIC, 14, struct btrfs_ioctl_vol_args)
+#define BTRFS_IOC_SNAP_DESTROY _IOW(BTRFS_IOCTL_MAGIC, 15, struct btrfs_ioctl_vol_args)
+#define BTRFS_IOC_SNAP_CREATE_V2 _IOW(BTRFS_IOCTL_MAGIC, 23, struct btrfs_ioctl_vol_args_v2)
+
+struct btrfs_ioctl_vol_args
+{
+    __s64 fd;
+    char name[BTRFS_PATH_NAME_MAX + 1];
+};
+
+struct btrfs_ioctl_vol_args_v2
+{
+    __s64 fd;
+    __u64 transid;
+    __u64 flags;
+    __u64 unused[4];
+    char name[BTRFS_SUBVOL_NAME_MAX + 1];
+};
+
+
 namespace snapper
 {
 
@@ -65,18 +92,26 @@ namespace snapper
     void
     Btrfs::createConfig() const
     {
-       SystemCmd cmd2(BTRFSBIN " subvolume create " + quote(subvolume + "/.snapshots"));
-       if (cmd2.retcode() != 0)
+       SDir subvolume_dir = openSubvolumeDir();
+
+       if (!create_subvolume(subvolume_dir.fd(), ".snapshots"))
+       {
+           y2err("create subvolume failed errno:" << errno << " (" << stringerror(errno) << ")");
            throw CreateConfigFailedException("creating btrfs snapshot failed");
+       }
     }
 
 
     void
     Btrfs::deleteConfig() const
     {
-       SystemCmd cmd2(BTRFSBIN " subvolume delete " + quote(subvolume + "/.snapshots"));
-       if (cmd2.retcode() != 0)
+       SDir subvolume_dir = openSubvolumeDir();
+
+       if (!delete_subvolume(subvolume_dir.fd(), ".snapshots"))
+       {
+           y2err("delete subvolume failed errno:" << errno << " (" << stringerror(errno) << ")");
            throw DeleteConfigFailedException("deleting btrfs snapshot failed");
+       }
     }
 
 
@@ -95,10 +130,17 @@ namespace snapper
     }
 
 
+    SDir
+    Btrfs::openSubvolumeDir() const
+    {
+       return SDir(subvolume);
+    }
+
+
     SDir
     Btrfs::openInfosDir() const
     {
-       SDir subvolume_dir(subvolume);
+       SDir subvolume_dir = openSubvolumeDir();
        SDir infos_dir(subvolume_dir, ".snapshots");
 
        struct stat stat;
@@ -140,19 +182,27 @@ namespace snapper
     void
     Btrfs::createSnapshot(unsigned int num) const
     {
-       SystemCmd cmd(BTRFSBIN " subvolume snapshot -r " + quote(subvolume) + " " +
-                     quote(snapshotDir(num)));
-       if (cmd.retcode() != 0)
+       SDir subvolume_dir = openSubvolumeDir();
+       SDir info_dir = openInfoDir(num);
+
+       if (!create_snapshot(subvolume_dir.fd(), info_dir.fd(), "snapshot"))
+       {
+           y2err("create snapshot failed errno:" << errno << " (" << stringerror(errno) << ")");
            throw CreateSnapshotFailedException();
+       }
     }
 
 
     void
     Btrfs::deleteSnapshot(unsigned int num) const
     {
-       SystemCmd cmd(BTRFSBIN " subvolume delete " + quote(snapshotDir(num)));
-       if (cmd.retcode() != 0)
+       SDir info_dir = openInfoDir(num);
+
+       if (!delete_subvolume(info_dir.fd(), "snapshot"))
+       {
+           y2err("delete snapshot failed errno:" << errno << " (" << stringerror(errno) << ")");
            throw DeleteSnapshotFailedException();
+       }
     }
 
 
@@ -184,7 +234,8 @@ namespace snapper
 
            struct stat stat;
            int r = info_dir.stat("snapshot", &stat, AT_SYMLINK_NOFOLLOW);
-           return r == 0 && S_ISDIR(stat.st_mode);
+           // check st_ino == 256 is copied from btrfsprogs
+           return r == 0 && stat.st_ino == 256 && S_ISDIR(stat.st_mode);
        }
        catch (const IOErrorException& e)
        {
@@ -193,6 +244,44 @@ namespace snapper
     }
 
 
+    bool
+    Btrfs::create_subvolume(int fddst, const string& name) const
+    {
+       struct btrfs_ioctl_vol_args args;
+       memset(&args, 0, sizeof(args));
+
+       strncpy(args.name, name.c_str(), BTRFS_PATH_NAME_MAX);
+
+        return ioctl(fddst, BTRFS_IOC_SUBVOL_CREATE, &args) == 0;
+    }
+
+
+    bool
+    Btrfs::create_snapshot(int fd, int fddst, const string& name) const
+    {
+       struct btrfs_ioctl_vol_args_v2 args;
+       memset(&args, 0, sizeof(args));
+
+       args.fd = fd;
+       args.flags |= BTRFS_SUBVOL_RDONLY;
+       strncpy(args.name, name.c_str(), BTRFS_SUBVOL_NAME_MAX);
+
+       return ioctl(fddst, BTRFS_IOC_SNAP_CREATE_V2, &args) == 0;
+    }
+
+
+    bool
+    Btrfs::delete_subvolume(int fd, const string& name) const
+    {
+       struct btrfs_ioctl_vol_args args;
+       memset(&args, 0, sizeof(args));
+
+       strncpy(args.name, name.c_str(), BTRFS_PATH_NAME_MAX);
+
+       return ioctl(fd, BTRFS_IOC_SNAP_DESTROY, &args) == 0;
+    }
+
+
     Ext4::Ext4(const string& subvolume)
        : Filesystem(subvolume)
     {

diff --git a/snapper/Filesystem.h b/snapper/Filesystem.h
index 872c10a23e112953ce175ff9a1ddb3f9bc5c12d5..4d0c876c4026359c137afdac5cb8940ba9984f90 100644 (file)
--- a/snapper/Filesystem.h
+++ b/snapper/Filesystem.h
@@ -87,6 +87,7 @@ namespace snapper
        virtual string infosDir() const;
        virtual string snapshotDir(unsigned int num) const;
 
+       virtual SDir openSubvolumeDir() const;
        virtual SDir openInfosDir() const;
        virtual SDir openInfoDir(unsigned int num) const;
        virtual SDir openSnapshotDir(unsigned int num) const;
@@ -100,6 +101,12 @@ namespace snapper
 
        virtual bool checkSnapshot(unsigned int num) const;
 
+    private:
+
+       bool create_subvolume(int fddst, const string& name) const;
+       bool create_snapshot(int fd, int fddst, const string& name) const;
+       bool delete_subvolume(int fd, const string& name) const;
+
     };