From 32c3cf028e747d1e9cf0679b16dcbe3794fe4853 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 9 Oct 2017 12:15:43 -0700 Subject: fscrypt: new helper function - fscrypt_prepare_lookup() Introduce a helper function which prepares to look up the given dentry in the given directory. If the directory is encrypted, it handles loading the directory's encryption key, setting the dentry's ->d_op to fscrypt_d_ops, and setting DCACHE_ENCRYPTED_WITH_KEY if the directory's encryption key is available. Note: once all filesystems switch over to this, we'll be able to move fscrypt_d_ops and fscrypt_set_encrypted_dentry() to fscrypt_private.h. Acked-by: Dave Chinner Signed-off-by: Eric Biggers Signed-off-by: Theodore Ts'o --- include/linux/fscrypt.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'include/linux/fscrypt.h') diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index c422367baed9..2327859c8cd2 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -237,4 +237,32 @@ static inline int fscrypt_prepare_rename(struct inode *old_dir, return 0; } +/** + * fscrypt_prepare_lookup - prepare to lookup a name in a possibly-encrypted directory + * @dir: directory being searched + * @dentry: filename being looked up + * @flags: lookup flags + * + * Prepare for ->lookup() in a directory which may be encrypted. Lookups can be + * done with or without the directory's encryption key; without the key, + * filenames are presented in encrypted form. Therefore, we'll try to set up + * the directory's encryption key, but even without it the lookup can continue. + * + * To allow invalidating stale dentries if the directory's encryption key is + * added later, we also install a custom ->d_revalidate() method and use the + * DCACHE_ENCRYPTED_WITH_KEY flag to indicate whether a given dentry is a + * plaintext name (flag set) or a ciphertext name (flag cleared). + * + * Return: 0 on success, -errno if a problem occurred while setting up the + * encryption key + */ +static inline int fscrypt_prepare_lookup(struct inode *dir, + struct dentry *dentry, + unsigned int flags) +{ + if (IS_ENCRYPTED(dir)) + return __fscrypt_prepare_lookup(dir, dentry); + return 0; +} + #endif /* _LINUX_FSCRYPT_H */ -- cgit v1.2.3