fscrypt_d_revalidate(): use stable parent inode passed by caller

The only thing it's using is parent directory inode and we are already
given a stable reference to that - no need to bother with boilerplate.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 389f5b2bf63b202d8fa06ed9e7f0d22b853dff71..010f9c0a4c2f1b4402d674814db4faf600a0c58a 100644 (file)
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -574,12 +574,10 @@ EXPORT_SYMBOL_GPL(fscrypt_fname_siphash);
  * Validate dentries in encrypted directories to make sure we aren't potentially
  * caching stale dentries after a key has been added.
  */
-int fscrypt_d_revalidate(struct inode *parent_dir, const struct qstr *name,
+int fscrypt_d_revalidate(struct inode *dir, const struct qstr *name,
                         struct dentry *dentry, unsigned int flags)
 {
-       struct dentry *dir;
        int err;
-       int valid;
 
        /*
         * Plaintext names are always valid, since fscrypt doesn't support
@@ -592,30 +590,21 @@ int fscrypt_d_revalidate(struct inode *parent_dir, const struct qstr *name,
        /*
         * No-key name; valid if the directory's key is still unavailable.
         *
-        * Although fscrypt forbids rename() on no-key names, we still must use
-        * dget_parent() here rather than use ->d_parent directly.  That's
-        * because a corrupted fs image may contain directory hard links, which
-        * the VFS handles by moving the directory's dentry tree in the dcache
-        * each time ->lookup() finds the directory and it already has a dentry
-        * elsewhere.  Thus ->d_parent can be changing, and we must safely grab
-        * a reference to some ->d_parent to prevent it from being freed.
+        * Note in RCU mode we have to bail if we get here -
+        * fscrypt_get_encryption_info() may block.
         */
 
        if (flags & LOOKUP_RCU)
                return -ECHILD;
 
-       dir = dget_parent(dentry);
        /*
         * Pass allow_unsupported=true, so that files with an unsupported
         * encryption policy can be deleted.
         */
-       err = fscrypt_get_encryption_info(d_inode(dir), true);
-       valid = !fscrypt_has_encryption_key(d_inode(dir));
-       dput(dir);
-
+       err = fscrypt_get_encryption_info(dir, true);
        if (err < 0)
                return err;
 
-       return valid;
+       return !fscrypt_has_encryption_key(dir);
 }
 EXPORT_SYMBOL_GPL(fscrypt_d_revalidate);