fscrypt: track master key presence separately from secret

[linux-2.6-microblaze.git] / fs / crypto / keysetup.c

diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c
index 094d1b7..d71f7c7 100644 (file)
--- a/fs/crypto/keysetup.c
+++ b/fs/crypto/keysetup.c
@@ -486,8 +486,8 @@ static int setup_file_encryption_key(struct fscrypt_inode_info *ci,
        }
        down_read(&mk->mk_sem);
 
-       /* Has the secret been removed (via FS_IOC_REMOVE_ENCRYPTION_KEY)? */
-       if (!is_master_key_secret_present(&mk->mk_secret)) {
+       if (!mk->mk_present) {
+               /* FS_IOC_REMOVE_ENCRYPTION_KEY has been executed on this key */
                err = -ENOKEY;
                goto out_release_key;
        }
@@ -539,8 +539,8 @@ static void put_crypt_info(struct fscrypt_inode_info *ci)
                /*
                 * Remove this inode from the list of inodes that were unlocked
                 * with the master key.  In addition, if we're removing the last
-                * inode from a master key struct that already had its secret
-                * removed, then complete the full removal of the struct.
+                * inode from an incompletely removed key, then complete the
+                * full removal of the key.
                 */
                spin_lock(&mk->mk_decrypted_inodes_lock);
                list_del(&ci->ci_master_key_link);
@@ -801,13 +801,14 @@ int fscrypt_drop_inode(struct inode *inode)
                return 0;
 
        /*
-        * Note: since we aren't holding the key semaphore, the result here can
+        * We can't take ->mk_sem here, since this runs in atomic context.
+        * Therefore, ->mk_present can change concurrently, and our result may
         * immediately become outdated.  But there's no correctness problem with
         * unnecessarily evicting.  Nor is there a correctness problem with not
         * evicting while iput() is racing with the key being removed, since
         * then the thread removing the key will either evict the inode itself
         * or will correctly detect that it wasn't evicted due to the race.
         */
-       return !is_master_key_secret_present(&ci->ci_master_key->mk_secret);
+       return !READ_ONCE(ci->ci_master_key->mk_present);
 }
 EXPORT_SYMBOL_GPL(fscrypt_drop_inode);