fs: Remove ext3 filesystem driver

The functionality of ext3 is fully supported by ext4 driver. Major
distributions (SUSE, RedHat) already use ext4 driver to handle ext3
filesystems for quite some time. There is some ugliness in mm resulting
from jbd cleaning buffers in a dirty page without cleaning page dirty
bit and also support for buffer bouncing in the block layer when stable
pages are required is there only because of jbd. So let's remove the
ext3 driver. This saves us some 28k lines of duplicated code.

Acked-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 58987b5..06b4b14 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -84,7 +84,7 @@
 static void ext4_clear_request_list(void);
 static int ext4_reserve_clusters(struct ext4_sb_info *, ext4_fsblk_t);
 
-#if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
+#if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT2)
 static struct file_system_type ext2_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "ext2",
@@ -100,7 +100,6 @@
 #endif
 
 
-#if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
 static struct file_system_type ext3_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "ext3",
@@ -111,9 +110,6 @@
 MODULE_ALIAS_FS("ext3");
 MODULE_ALIAS("ext3");
 #define IS_EXT3_SB(sb) ((sb)->s_bdev->bd_holder == &ext3_fs_type)
-#else
-#define IS_EXT3_SB(sb) (0)
-#endif
 
 static int ext4_verify_csum_type(struct super_block *sb,
 				 struct ext4_super_block *es)
@@ -5500,7 +5496,7 @@
 	return mount_bdev(fs_type, flags, dev_name, data, ext4_fill_super);
 }
 
-#if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
+#if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT2)
 static inline void register_as_ext2(void)
 {
 	int err = register_filesystem(&ext2_fs_type);
@@ -5530,7 +5526,6 @@
 static inline int ext2_feature_set_ok(struct super_block *sb) { return 0; }
 #endif
 
-#if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
 static inline void register_as_ext3(void)
 {
 	int err = register_filesystem(&ext3_fs_type);
@@ -5556,11 +5551,6 @@
 		return 0;
 	return 1;
 }
-#else
-static inline void register_as_ext3(void) { }
-static inline void unregister_as_ext3(void) { }
-static inline int ext3_feature_set_ok(struct super_block *sb) { return 0; }
-#endif
 
 static struct file_system_type ext4_fs_type = {
 	.owner		= THIS_MODULE,