fscrypt: clear keyring before calling key_put()

Now that the key quotas are handled immediately on key_put() instead of
being postponed to the key management garbage collection worker, a call
to keyring_clear() is all that is required in fscrypt_put_master_key()
so that the keyring clean-up is also done synchronously.  This patch
should fix the fstest generic/581 flakiness.

Signed-off-by: Luis Henriques <lhenriques@suse.de>
Link: https://lore.kernel.org/r/20240206101619.8083-1-lhenriques@suse.de
[ebiggers: added comment]
Signed-off-by: Eric Biggers <ebiggers@google.com>

diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c
index 0edf0b58daa764338684aeb0623bd9c95d65d6f2..6681a71625f0a32d9f7779728edbc6452cdc22a5 100644 (file)
--- a/fs/crypto/keyring.c
+++ b/fs/crypto/keyring.c
@@ -74,8 +74,12 @@ void fscrypt_put_master_key(struct fscrypt_master_key *mk)
         * that concurrent keyring lookups can no longer find it.
         */
        WARN_ON_ONCE(refcount_read(&mk->mk_active_refs) != 0);
-       key_put(mk->mk_users);
-       mk->mk_users = NULL;
+       if (mk->mk_users) {
+               /* Clear the keyring so the quota gets released right away. */
+               keyring_clear(mk->mk_users);
+               key_put(mk->mk_users);
+               mk->mk_users = NULL;
+       }
        call_rcu(&mk->mk_rcu_head, fscrypt_free_master_key);
 }