[PATCH RFC DRAFT v2 03/13] ext4: move fscrypt to filesystem inode

Christian Brauner
2025-07-22T12:57:55Z

Move fscrypt data pointer into the filesystem's private inode and record
the offset from the embedded struct inode.

This will allow us to drop the fscrypt data pointer from struct inode
itself and move it into the filesystem's inode.

Signed-off-by: Christian Brauner <brauner@kernel.org>
---
fs/ext4/ext4.h | 5 +++++
fs/ext4/file.c | 4 ++++
fs/ext4/ialloc.c | 2 ++
fs/ext4/inode.c | 1 +
fs/ext4/mballoc.c | 3 +++
fs/ext4/namei.c | 15 +++++++++++++++
fs/ext4/super.c | 3 +++
fs/ext4/symlink.c | 12 ++++++++++++
8 files changed, 45 insertions(+)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 18373de980f2..e9710366d87a 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1197,6 +1197,10 @@ struct ext4_inode_info {
__u32 i_csum_seed;

kprojid_t i_projid;
+
+#ifdef CONFIG_FS_ENCRYPTION
+ struct fscrypt_inode_info *i_fscrypt_info;
+#endif
};

/*
@@ -3604,6 +3608,7 @@ int ext4_enable_quotas(struct super_block *sb);
extern const struct file_operations ext4_dir_operations;

/* file.c */
+extern const struct inode_operations ext4_encrypted_nop_operations;
extern const struct inode_operations ext4_file_inode_operations;
extern const struct file_operations ext4_file_operations;
extern loff_t ext4_llseek(struct file *file, loff_t offset, int origin);
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 21df81347147..9bdee2757bdf 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -981,6 +981,10 @@ const struct file_operations ext4_file_operations = {
};

const struct inode_operations ext4_file_inode_operations = {
+#ifdef CONFIG_FS_ENCRYPTION
+ .i_fscrypt = offsetof(struct ext4_inode_info, i_fscrypt_info) -
+ offsetof(struct ext4_inode_info, vfs_inode),
+#endif
.setattr = ext4_setattr,
.getattr = ext4_file_getattr,
.listxattr = ext4_listxattr,
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 79aa3df8d019..cf1f9c307b9c 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -979,6 +979,8 @@ struct inode *__ext4_new_inode(struct mnt_idmap *idmap,
} else
inode_init_owner(idmap, inode, dir, mode);

+ inode->i_op = &ext4_encrypted_nop_operations;
+
if (ext4_has_feature_project(sb) &&
ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT))
ei->i_projid = EXT4_I(dir)->i_projid;
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index be9a4cba35fd..ce385d9c1683 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5163,6 +5163,7 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
return inode;
}

+ inode->i_op = &ext4_encrypted_nop_operations;
ei = EXT4_I(inode);
iloc.bh = NULL;

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 1e98c5be4e0a..9b93ee2bfd6a 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3417,6 +3417,9 @@ static int ext4_mb_init_backend(struct super_block *sb)
ext4_msg(sb, KERN_ERR, "can't get new inode");
goto err_freesgi;
}
+
+ sbi->s_buddy_cache->i_op = &ext4_encrypted_nop_operations;
+
/* To avoid potentially colliding with an valid on-disk inode number,
* use EXT4_BAD_INO for the buddy cache inode number. This inode is
* not in the inode hash, so it should never be found by iget(), but
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index a178ac229489..fb953834265c 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -4206,7 +4206,18 @@ static int ext4_rename2(struct mnt_idmap *idmap,
/*
* directories can handle most operations...
*/
+const struct inode_operations ext4_encrypted_nop_operations = {
+#ifdef CONFIG_FS_ENCRYPTION
+ .i_fscrypt = offsetof(struct ext4_inode_info, i_fscrypt_info) -
+ offsetof(struct ext4_inode_info, vfs_inode),
+#endif
+};
+
const struct inode_operations ext4_dir_inode_operations = {
+#ifdef CONFIG_FS_ENCRYPTION
+ .i_fscrypt = offsetof(struct ext4_inode_info, i_fscrypt_info) -
+ offsetof(struct ext4_inode_info, vfs_inode),
+#endif
.create = ext4_create,
.lookup = ext4_lookup,
.link = ext4_link,
@@ -4228,6 +4239,10 @@ const struct inode_operations ext4_dir_inode_operations = {
};

const struct inode_operations ext4_special_inode_operations = {
+#ifdef CONFIG_FS_ENCRYPTION
+ .i_fscrypt = offsetof(struct ext4_inode_info, i_fscrypt_info) -
+ offsetof(struct ext4_inode_info, vfs_inode),
+#endif
.setattr = ext4_setattr,
.getattr = ext4_getattr,
.listxattr = ext4_listxattr,
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index c7d39da7e733..6085d6c9169b 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1412,6 +1412,9 @@ static struct inode *ext4_alloc_inode(struct super_block *sb)
INIT_WORK(&ei->i_rsv_conversion_work, ext4_end_io_rsv_work);
ext4_fc_init_inode(&ei->vfs_inode);
spin_lock_init(&ei->i_fc_lock);
+#ifdef CONFIG_FS_ENCRYPTION
+ ei->i_fscrypt_info = NULL;
+#endif
return &ei->vfs_inode;
}

diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c
index 645240cc0229..6b67a9a5c02c 100644
--- a/fs/ext4/symlink.c
+++ b/fs/ext4/symlink.c
@@ -115,6 +115,10 @@ static const char *ext4_get_link(struct dentry *dentry, struct inode *inode,
}

const struct inode_operations ext4_encrypted_symlink_inode_operations = {
+#ifdef CONFIG_FS_ENCRYPTION
+ .i_fscrypt = offsetof(struct ext4_inode_info, i_fscrypt_info) -
+ offsetof(struct ext4_inode_info, vfs_inode),
+#endif
.get_link = ext4_encrypted_get_link,
.setattr = ext4_setattr,
.getattr = ext4_encrypted_symlink_getattr,
@@ -122,6 +126,10 @@ const struct inode_operations ext4_encrypted_symlink_inode_operations = {
};

const struct inode_operations ext4_symlink_inode_operations = {
+#ifdef CONFIG_FS_ENCRYPTION
+ .i_fscrypt = offsetof(struct ext4_inode_info, i_fscrypt_info) -
+ offsetof(struct ext4_inode_info, vfs_inode),
+#endif
.get_link = ext4_get_link,
.setattr = ext4_setattr,
.getattr = ext4_getattr,
@@ -129,6 +137,10 @@ const struct inode_operations ext4_symlink_inode_operations = {
};

const struct inode_operations ext4_fast_symlink_inode_operations = {
+#ifdef CONFIG_FS_ENCRYPTION
+ .i_fscrypt = offsetof(struct ext4_inode_info, i_fscrypt_info) -
+ offsetof(struct ext4_inode_info, vfs_inode),
+#endif
.get_link = simple_get_link,
.setattr = ext4_setattr,
.getattr = ext4_getattr,

--
2.47.2