[PATCH v4 2/3] fscrypt: Have filesystems handle their d_ops

From: Daniel Rosenberg
Date: Thu Nov 19 2020 - 01:09:34 EST


This shifts the responsibility of setting up dentry operations from
fscrypt to the individual filesystems, allowing them to have their own
operations while still setting fscrypt's d_revalidate as appropriate.

Most filesystems can just use generic_set_encrypted_ci_d_ops, unless
they have their own specific dentry operations as well. That operation
will set the minimal d_ops required under the circumstances.

Since the fscrypt d_ops are set later on, we must set all d_ops there,
since we cannot adjust those later on. This should not result in any
change in behavior.

Signed-off-by: Daniel Rosenberg <drosen@xxxxxxxxxx>
Acked-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
fs/crypto/fname.c | 4 ----
fs/crypto/fscrypt_private.h | 1 -
fs/crypto/hooks.c | 1 -
fs/ext4/dir.c | 7 -------
fs/ext4/ext4.h | 4 ----
fs/ext4/namei.c | 1 +
fs/ext4/super.c | 5 -----
fs/f2fs/dir.c | 7 -------
fs/f2fs/f2fs.h | 3 ---
fs/f2fs/namei.c | 1 +
fs/f2fs/super.c | 1 -
fs/ubifs/dir.c | 1 +
include/linux/fscrypt.h | 7 +++++--
13 files changed, 8 insertions(+), 35 deletions(-)

diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 1fbe6c24d705..cb3cfa6329ba 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -570,7 +570,3 @@ int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
return valid;
}
EXPORT_SYMBOL_GPL(fscrypt_d_revalidate);
-
-const struct dentry_operations fscrypt_d_ops = {
- .d_revalidate = fscrypt_d_revalidate,
-};
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 4f5806a3b73d..df9c48c1fbf7 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -294,7 +294,6 @@ int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname,
bool fscrypt_fname_encrypted_size(const union fscrypt_policy *policy,
u32 orig_len, u32 max_len,
u32 *encrypted_len_ret);
-extern const struct dentry_operations fscrypt_d_ops;

/* hkdf.c */

diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c
index 20b0df47fe6a..9006fa983335 100644
--- a/fs/crypto/hooks.c
+++ b/fs/crypto/hooks.c
@@ -117,7 +117,6 @@ int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry,
spin_lock(&dentry->d_lock);
dentry->d_flags |= DCACHE_NOKEY_NAME;
spin_unlock(&dentry->d_lock);
- d_set_d_op(dentry, &fscrypt_d_ops);
}
return err;
}
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index ca50c90adc4c..e757319a4472 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -667,10 +667,3 @@ const struct file_operations ext4_dir_operations = {
.open = ext4_dir_open,
.release = ext4_release_dir,
};
-
-#ifdef CONFIG_UNICODE
-const struct dentry_operations ext4_dentry_ops = {
- .d_hash = generic_ci_d_hash,
- .d_compare = generic_ci_d_compare,
-};
-#endif
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index bf9429484462..ad77f01d9e20 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3380,10 +3380,6 @@ static inline void ext4_unlock_group(struct super_block *sb,
/* dir.c */
extern const struct file_operations ext4_dir_operations;

-#ifdef CONFIG_UNICODE
-extern const struct dentry_operations ext4_dentry_ops;
-#endif
-
/* file.c */
extern const struct inode_operations ext4_file_inode_operations;
extern const struct file_operations ext4_file_operations;
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 33509266f5a0..12a417ff5648 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1614,6 +1614,7 @@ static struct buffer_head *ext4_lookup_entry(struct inode *dir,
struct buffer_head *bh;

err = ext4_fname_prepare_lookup(dir, dentry, &fname);
+ generic_set_encrypted_ci_d_ops(dentry);
if (err == -ENOENT)
return NULL;
if (err)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 6633b20224d5..0288bedf46e1 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4968,11 +4968,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
goto failed_mount4;
}

-#ifdef CONFIG_UNICODE
- if (sb->s_encoding)
- sb->s_d_op = &ext4_dentry_ops;
-#endif
-
sb->s_root = d_make_root(root);
if (!sb->s_root) {
ext4_msg(sb, KERN_ERR, "get root dentry failed");
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 4b9ef8bbfa4a..71fdf5076461 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -1099,10 +1099,3 @@ const struct file_operations f2fs_dir_operations = {
.compat_ioctl = f2fs_compat_ioctl,
#endif
};
-
-#ifdef CONFIG_UNICODE
-const struct dentry_operations f2fs_dentry_ops = {
- .d_hash = generic_ci_d_hash,
- .d_compare = generic_ci_d_compare,
-};
-#endif
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index cb700d797296..62b4f31d30e2 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3767,9 +3767,6 @@ static inline void f2fs_update_sit_info(struct f2fs_sb_info *sbi) {}
#endif

extern const struct file_operations f2fs_dir_operations;
-#ifdef CONFIG_UNICODE
-extern const struct dentry_operations f2fs_dentry_ops;
-#endif
extern const struct file_operations f2fs_file_operations;
extern const struct inode_operations f2fs_file_inode_operations;
extern const struct address_space_operations f2fs_dblock_aops;
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 8fa37d1434de..6edb1ab579a1 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -497,6 +497,7 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
}

err = f2fs_prepare_lookup(dir, dentry, &fname);
+ generic_set_encrypted_ci_d_ops(dentry);
if (err == -ENOENT)
goto out_splice;
if (err)
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 00eff2f51807..f51d52591c99 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -3427,7 +3427,6 @@ static int f2fs_setup_casefold(struct f2fs_sb_info *sbi)

sbi->sb->s_encoding = encoding;
sbi->sb->s_encoding_flags = encoding_flags;
- sbi->sb->s_d_op = &f2fs_dentry_ops;
}
#else
if (f2fs_sb_has_casefold(sbi)) {
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index 155521e51ac5..7a920434d741 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -203,6 +203,7 @@ static struct dentry *ubifs_lookup(struct inode *dir, struct dentry *dentry,
dbg_gen("'%pd' in dir ino %lu", dentry, dir->i_ino);

err = fscrypt_prepare_lookup(dir, dentry, &nm);
+ generic_set_encrypted_ci_d_ops(dentry);
if (err == -ENOENT)
return d_splice_alias(NULL, dentry);
if (err)
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index a8f7a43f031b..e72f80482671 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -741,8 +741,11 @@ static inline int fscrypt_prepare_rename(struct inode *old_dir,
* directory's encryption key is available, then the lookup is assumed to be by
* plaintext name; otherwise, it is assumed to be by no-key name.
*
- * This also installs a custom ->d_revalidate() method which will invalidate the
- * dentry if it was created without the key and the key is later added.
+ * This will set DCACHE_NOKEY_NAME on the dentry if the lookup is by no-key
+ * name. In this case the filesystem must assign the dentry a dentry_operations
+ * which contains fscrypt_d_revalidate (or contains a d_revalidate method that
+ * calls fscrypt_d_revalidate), so that the dentry will be invalidated if the
+ * directory's encryption key is later added.
*
* Return: 0 on success; -ENOENT if the directory's key is unavailable but the
* filename isn't a valid no-key name, so a negative dentry should be created;
--
2.29.2.454.gaff20da3a2-goog