vold: Retry opening block device on failure when starting encryption

The device mapper storage device node can take some time to be
created; so retry.

Bug: 23024596
Change-Id: Ieeb3b697f9cef72d4ea9d106750696901f0a224d

cryptfs.c

@@ -2445,11 +2445,19 @@ static int cryptfs_enable_inplace_ext4(char *crypto_blkdev,
         goto errout;
     }
 
-    if ( (data.cryptofd = open(crypto_blkdev, O_WRONLY|O_CLOEXEC)) < 0) {
-        SLOGE("Error opening crypto_blkdev %s for ext4 inplace encrypt. err=%d(%s)\n",
-              crypto_blkdev, errno, strerror(errno));
-        rc = ENABLE_INPLACE_ERR_DEV;
-        goto errout;
+    // Wait until the block device appears.  Re-use the mount retry values since it is reasonable.
+    int retries = RETRY_MOUNT_ATTEMPTS;
+    while ((data.cryptofd = open(crypto_blkdev, O_WRONLY|O_CLOEXEC)) < 0) {
+        if (--retries) {
+            SLOGE("Error opening crypto_blkdev %s for ext4 inplace encrypt. err=%d(%s), retrying\n",
+                  crypto_blkdev, errno, strerror(errno));
+            sleep(RETRY_MOUNT_DELAY_SECONDS);
+        } else {
+            SLOGE("Error opening crypto_blkdev %s for ext4 inplace encrypt. err=%d(%s)\n",
+                  crypto_blkdev, errno, strerror(errno));
+            rc = ENABLE_INPLACE_ERR_DEV;
+            goto errout;
+        }
     }
 
     if (setjmp(setjmp_env)) {