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 @@ static int __init init_ext4_fs(void) static void __exit exit_ext4_fs(void) { + unregister_as_ext2(); + unregister_as_ext3(); unregister_filesystem(&ext4_fs_type); destroy_inodecache(); exit_ext4_xattr();