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-rw-r--r--fs/ext4/Kconfig10
-rw-r--r--fs/ext4/super.c58
2 files changed, 68 insertions, 0 deletions
diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig
index 9f2d45d75b1a..a6b4e93833d6 100644
--- a/fs/ext4/Kconfig
+++ b/fs/ext4/Kconfig
@@ -26,6 +26,16 @@ config EXT4_FS
If unsure, say N.
+config EXT4_USE_FOR_EXT23
+ bool "Use ext4 for ext2/ext3 file systems"
+ depends on !EXT3_FS || !EXT2_FS
+ default y
+ help
+ Allow the ext4 file system driver code to be used for ext2 or
+ ext3 file system mounts. This allows users to reduce their
+ compiled kernel size by using one file system driver for
+ ext2, ext3, and ext4 file systems.
+
config EXT4_FS_XATTR
bool "Ext4 extended attributes"
depends on EXT4_FS
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 5a2db612950b..30476daf966e 100644
--- 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();