[PATCH 11/20] fscrypt_d_revalidate(): use stable parent inode passed by caller

Al Viro
2025-01-10T02:43:06Z

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.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/crypto/fname.c | 21 +++++----------------
1 file changed, 5 insertions(+), 16 deletions(-)

diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 389f5b2bf63b..010f9c0a4c2f 100644
--- 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);
--
2.39.5