124 lines
3.4 KiB
Diff
124 lines
3.4 KiB
Diff
From 24b584240a0006ea7436cd35f5e8983eb76f1e6f Mon Sep 17 00:00:00 2001
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From: Theodore Ts'o <tytso@mit.edu>
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Date: Mon, 7 Dec 2009 14:08:51 -0500
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Subject: [PATCH] ext4: Use ext4 file system driver for ext2/ext3 file system mounts
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Add a new config option, CONFIG_EXT4_USE_FOR_EXT23 which if enabled,
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will cause ext4 to be used for either ext2 or ext3 file system mounts
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when ext2 or ext3 is not enabled in the configuration.
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This allows minimalist kernel fanatics to drop to file system drivers
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from their compiled kernel with out losing functionality.
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Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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---
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fs/ext4/Kconfig | 10 +++++++++
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fs/ext4/super.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
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2 files changed, 68 insertions(+), 0 deletions(-)
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--- a/fs/ext4/Kconfig
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+++ b/fs/ext4/Kconfig
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@@ -26,6 +26,16 @@ config EXT4_FS
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If unsure, say N.
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+config EXT4_USE_FOR_EXT23
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+ bool "Use ext4 for ext2/ext3 file systems"
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+ depends on !EXT3_FS || !EXT2_FS
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+ default y
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+ help
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+ Allow the ext4 file system driver code to be used for ext2 or
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+ ext3 file system mounts. This allows users to reduce their
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+ compiled kernel size by using one file system driver for
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+ ext2, ext3, and ext4 file systems.
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+
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config EXT4_FS_XATTR
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bool "Ext4 extended attributes"
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depends on EXT4_FS
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--- a/fs/ext4/super.c
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+++ b/fs/ext4/super.c
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@@ -3994,6 +3994,58 @@ static int ext4_get_sb(struct file_syste
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return get_sb_bdev(fs_type, flags, dev_name, data, ext4_fill_super,mnt);
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}
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+#if !defined(CONTIG_EXT2_FS) && defined(CONFIG_EXT4_USE_FOR_EXT23)
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+static struct file_system_type ext2_fs_type = {
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+ .owner = THIS_MODULE,
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+ .name = "ext2",
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+ .get_sb = ext4_get_sb,
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+ .kill_sb = kill_block_super,
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+ .fs_flags = FS_REQUIRES_DEV,
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+};
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+
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+static inline void register_as_ext2(void)
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+{
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+ int err = register_filesystem(&ext2_fs_type);
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+ if (err)
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+ printk(KERN_WARNING
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+ "EXT4-fs: Unable to register as ext2 (%d)\n", err);
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+}
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+
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+static inline void unregister_as_ext2(void)
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+{
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+ unregister_filesystem(&ext2_fs_type);
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+}
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+#else
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+static inline void register_as_ext2(void) { }
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+static inline void unregister_as_ext2(void) { }
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+#endif
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+
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+#if !defined(CONTIG_EXT3_FS) && defined(CONFIG_EXT4_USE_FOR_EXT23)
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+static struct file_system_type ext3_fs_type = {
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+ .owner = THIS_MODULE,
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+ .name = "ext3",
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+ .get_sb = ext4_get_sb,
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+ .kill_sb = kill_block_super,
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+ .fs_flags = FS_REQUIRES_DEV,
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+};
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+
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+static inline void register_as_ext3(void)
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+{
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+ int err = register_filesystem(&ext3_fs_type);
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+ if (err)
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+ printk(KERN_WARNING
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+ "EXT4-fs: Unable to register as ext3 (%d)\n", err);
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+}
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+
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+static inline void unregister_as_ext3(void)
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+{
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+ unregister_filesystem(&ext3_fs_type);
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+}
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+#else
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+static inline void register_as_ext3(void) { }
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+static inline void unregister_as_ext3(void) { }
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+#endif
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+
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static struct file_system_type ext4_fs_type = {
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.owner = THIS_MODULE,
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.name = "ext4",
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@@ -4024,11 +4076,15 @@ static int __init init_ext4_fs(void)
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err = init_inodecache();
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if (err)
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goto out1;
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+ register_as_ext2();
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+ register_as_ext3();
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err = register_filesystem(&ext4_fs_type);
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if (err)
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goto out;
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return 0;
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out:
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+ unregister_as_ext2();
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+ unregister_as_ext3();
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destroy_inodecache();
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out1:
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exit_ext4_xattr();
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@@ -4044,6 +4100,8 @@ out4:
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static void __exit exit_ext4_fs(void)
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{
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+ unregister_as_ext2();
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+ unregister_as_ext3();
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unregister_filesystem(&ext4_fs_type);
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destroy_inodecache();
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exit_ext4_xattr();
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