ext4: Use ext4 file system driver for ext2/ext3 file system mounts

[net-next-2.6.git] / fs / ext4 / super.c

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 5a2db612950b0c440b56edc529c68a116768bf9a..30476daf966e8f2c98937c9dede3e8a2fa3dea0c 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3960,6 +3960,58 @@ static int ext4_get_sb(struct file_system_type *fs_type, int flags,
        return get_sb_bdev(fs_type, flags, dev_name, data, ext4_fill_super,mnt);
 }
 
+#if !defined(CONTIG_EXT2_FS) && defined(CONFIG_EXT4_USE_FOR_EXT23)
+static struct file_system_type ext2_fs_type = {
+       .owner          = THIS_MODULE,
+       .name           = "ext2",
+       .get_sb         = ext4_get_sb,
+       .kill_sb        = kill_block_super,
+       .fs_flags       = FS_REQUIRES_DEV,
+};
+
+static inline void register_as_ext2(void)
+{
+       int err = register_filesystem(&ext2_fs_type);
+       if (err)
+               printk(KERN_WARNING
+                      "EXT4-fs: Unable to register as ext2 (%d)\n", err);
+}
+
+static inline void unregister_as_ext2(void)
+{
+       unregister_filesystem(&ext2_fs_type);
+}
+#else
+static inline void register_as_ext2(void) { }
+static inline void unregister_as_ext2(void) { }
+#endif
+
+#if !defined(CONTIG_EXT3_FS) && defined(CONFIG_EXT4_USE_FOR_EXT23)
+static struct file_system_type ext3_fs_type = {
+       .owner          = THIS_MODULE,
+       .name           = "ext3",
+       .get_sb         = ext4_get_sb,
+       .kill_sb        = kill_block_super,
+       .fs_flags       = FS_REQUIRES_DEV,
+};
+
+static inline void register_as_ext3(void)
+{
+       int err = register_filesystem(&ext3_fs_type);
+       if (err)
+               printk(KERN_WARNING
+                      "EXT4-fs: Unable to register as ext3 (%d)\n", err);
+}
+
+static inline void unregister_as_ext3(void)
+{
+       unregister_filesystem(&ext3_fs_type);
+}
+#else
+static inline void register_as_ext3(void) { }
+static inline void unregister_as_ext3(void) { }
+#endif
+
 static struct file_system_type ext4_fs_type = {
        .owner          = THIS_MODULE,
        .name           = "ext4",
@@ -3989,11 +4041,15 @@ static int __init init_ext4_fs(void)
        err = init_inodecache();
        if (err)
                goto out1;
+       register_as_ext2();
+       register_as_ext3();
        err = register_filesystem(&ext4_fs_type);
        if (err)
                goto out;
        return 0;
 out:
+       unregister_as_ext2();
+       unregister_as_ext3();
        destroy_inodecache();
 out1:
        exit_ext4_xattr();
@@ -4009,6 +4065,8 @@ out4:
 
 static void __exit exit_ext4_fs(void)
 {
+       unregister_as_ext2();
+       unregister_as_ext3();
        unregister_filesystem(&ext4_fs_type);
        destroy_inodecache();
        exit_ext4_xattr();