[PATCH 1/4] fscrypt: Implement FS_CFLG_OWN_D_OPS

[Richard Weinberger <richard@nod.at>]

If a filesystem sets FS_CFLG_OWN_D_OPS it manages dentry operations
itself and fscrypt is not allowed to set them.

Signed-off-by: Richard Weinberger <richard@nod.at>
---
 fs/crypto/hooks.c       | 4 +++-
 include/linux/fscrypt.h | 1 +
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c
index 56debb1fcf5e..3ec925405fbe 100644
--- a/fs/crypto/hooks.c
+++ b/fs/crypto/hooks.c
@@ -107,7 +107,9 @@ int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry)
 		spin_unlock(&dentry->d_lock);
 	}
 
-	d_set_d_op(dentry, &fscrypt_d_ops);
+	if ((dir->i_sb->s_cop->flags & FS_CFLG_OWN_D_OPS) == 0)
+		d_set_d_op(dentry, &fscrypt_d_ops);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(__fscrypt_prepare_lookup);
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index e5194fc3983e..7139a110ac4f 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -48,6 +48,7 @@ struct fscrypt_name {
  * fscrypt superblock flags
  */
 #define FS_CFLG_OWN_PAGES (1U << 1)
+#define FS_CFLG_OWN_D_OPS (1U << 2)
 
 /*
  * crypto operations for filesystems
-- 
2.21.0