From b6df0138e5eb6052e16d2cd63045332c68b14cf0 Mon Sep 17 00:00:00 2001
From: David Anderson <dvander@google.com>
Date: Wed, 21 Jun 2023 12:40:12 -0700
Subject: [PATCH] snapuserd: Return void from RespondIOError.

RespondIOError could return "true" which is not the correct value for
its callers, usually. However since RespondIOError is not specifically
needed anymore, we can also avoid calling it in most places.

This also fixes a bug where ReadUnalignedSector's return value was
implicitly converted to boolean.

Bug: 288273605
Test: snapuserd_test
Change-Id: I62140b2b05d0f9f53cb669c5c0d7e0ffc7f4c9a1
---
 .../user-space-merge/snapuserd_core.h         |  2 +-
 .../user-space-merge/snapuserd_dm_user.cpp    | 23 ++++++-------------
 2 files changed, 8 insertions(+), 17 deletions(-)

diff --git a/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_core.h b/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_core.h
index cf3887584..7cffc1c4b 100644
--- a/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_core.h
+++ b/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_core.h
@@ -134,7 +134,7 @@ class Worker {
     bool ReadUnalignedSector(sector_t sector, size_t size);
     int ReadUnalignedSector(sector_t sector, size_t size,
                             std::vector<std::pair<sector_t, const CowOperation*>>::iterator& it);
-    bool RespondIOError();
+    void RespondIOError();
 
     // Processing COW operations
     bool ProcessCowOp(const CowOperation* cow_op);
diff --git a/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_dm_user.cpp b/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_dm_user.cpp
index c505c32a1..0eb2a14fe 100644
--- a/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_dm_user.cpp
+++ b/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_dm_user.cpp
@@ -392,10 +392,7 @@ bool Worker::ReadAlignedSector(sector_t sector, size_t sz) {
 
             // Just return the header if it is an error
             if (header->type == DM_USER_RESP_ERROR) {
-                if (!RespondIOError()) {
-                    return false;
-                }
-
+                RespondIOError();
                 io_error = true;
                 break;
             }
@@ -537,7 +534,7 @@ bool Worker::ReadUnalignedSector(sector_t sector, size_t size) {
         if (ret < 0) {
             SNAP_LOG(ERROR) << "ReadUnalignedSector failed for sector: " << sector
                             << " size: " << size << " it->sector: " << it->first;
-            return RespondIOError();
+            return false;
         }
 
         remaining_size -= ret;
@@ -565,7 +562,7 @@ bool Worker::ReadUnalignedSector(sector_t sector, size_t size) {
         CHECK(diff_size <= BLOCK_SZ);
         if (remaining_size < diff_size) {
             if (!ReadDataFromBaseDevice(sector, remaining_size)) {
-                return RespondIOError();
+                return false;
             }
             total_bytes_read += remaining_size;
 
@@ -574,7 +571,7 @@ bool Worker::ReadUnalignedSector(sector_t sector, size_t size) {
             }
         } else {
             if (!ReadDataFromBaseDevice(sector, diff_size)) {
-                return RespondIOError();
+                return false;
             }
 
             total_bytes_read += diff_size;
@@ -596,7 +593,7 @@ bool Worker::ReadUnalignedSector(sector_t sector, size_t size) {
     return true;
 }
 
-bool Worker::RespondIOError() {
+void Worker::RespondIOError() {
     struct dm_user_header* header = bufsink_.GetHeaderPtr();
     header->type = DM_USER_RESP_ERROR;
     // This is an issue with the dm-user interface. There
@@ -610,13 +607,7 @@ bool Worker::RespondIOError() {
     // TODO: Fix the interface
     CHECK(header_response_);
 
-    if (!WriteDmUserPayload(0)) {
-        return false;
-    }
-
-    // There is no need to process further as we have already seen
-    // an I/O error
-    return true;
+    WriteDmUserPayload(0);
 }
 
 bool Worker::DmuserReadRequest() {
@@ -624,7 +615,7 @@ bool Worker::DmuserReadRequest() {
 
     // Unaligned I/O request
     if (!IsBlockAligned(header->sector << SECTOR_SHIFT)) {
-        return ReadUnalignedSector(header->sector, header->len);
+        return ReadUnalignedSector(header->sector, header->len) != -1;
     }
 
     return ReadAlignedSector(header->sector, header->len);