All dentries in a case-insensitive filesystem have the same set of
dentry operations.  Therefore, we should let VFS propagate them from
sb->s_d_op d_alloc instead of setting at lookup time.

This was already the case before commit bb9cd9106b22 ("fscrypt: Have
filesystems handle their d_ops"), but it was changed to set at
lookup-time to facilitate the integration with fscrypt.  But it's a
problem because dentries that don't get created through ->lookup() won't
have any visibility of the operations.  Let's revert to the previous
implementation.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Gabriel Krisman Bertazi <redacted>

---
changes since v1:
  - Fix CONFIG_UNICODE=n build (lkp)
---
 fs/f2fs/namei.c | 6 +++++-
 fs/f2fs/super.c | 5 +++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index d0053b0284d8..6aec21f0b5d6 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c

@@ -532,7 +532,11 @@ 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);
+
+	/* Case-insensitive volumes set dentry ops through sb->s_d_op. */
+	if (!dir->i_sb->s_d_op)
+		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 033af907c3b1..8d1abd7f3a6f 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c

@@ -4663,6 +4663,11 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 		goto free_node_inode;
 	}
 
+#if IS_ENABLED(CONFIG_UNICODE)
+	if (sb->s_encoding)
+		sb->s_d_op = &generic_ci_dentry_ops;
+#endif
+
 	sb->s_root = d_make_root(root); /* allocate root dentry */
 	if (!sb->s_root) {
 		err = -ENOMEM;

-- 
2.43.0