diff --git a/common/utils.cc b/common/utils.cc
index c8924b1..66fd12d 100644
--- a/common/utils.cc
+++ b/common/utils.cc
@@ -192,10 +192,10 @@
   return true;
 }
 
-bool PWriteAll(const FileDescriptorPtr& fd,
-               const void* buf,
-               size_t count,
-               off_t offset) {
+bool WriteAll(const FileDescriptorPtr& fd,
+              const void* buf,
+              size_t count,
+              off_t offset) {
   TEST_AND_RETURN_FALSE_ERRNO(fd->Seek(offset, SEEK_SET) !=
                               static_cast<off_t>(-1));
   return WriteAll(fd, buf, count);
@@ -218,11 +218,11 @@
   return true;
 }
 
-bool PReadAll(const FileDescriptorPtr& fd,
-              void* buf,
-              size_t count,
-              off_t offset,
-              ssize_t* out_bytes_read) {
+bool ReadAll(const FileDescriptorPtr& fd,
+             void* buf,
+             size_t count,
+             off_t offset,
+             ssize_t* out_bytes_read) {
   TEST_AND_RETURN_FALSE_ERRNO(fd->Seek(offset, SEEK_SET) !=
                               static_cast<off_t>(-1));
   char* c_buf = static_cast<char*>(buf);
diff --git a/common/utils.h b/common/utils.h
index 05a92be..0762796 100644
--- a/common/utils.h
+++ b/common/utils.h
@@ -18,6 +18,7 @@
 #define UPDATE_ENGINE_COMMON_UTILS_H_
 
 #include <errno.h>
+#include <sys/types.h>
 #include <time.h>
 #include <unistd.h>
 
@@ -63,10 +64,11 @@
 bool PWriteAll(int fd, const void* buf, size_t count, off_t offset);
 
 bool WriteAll(const FileDescriptorPtr& fd, const void* buf, size_t count);
-bool PWriteAll(const FileDescriptorPtr& fd,
-               const void* buf,
-               size_t count,
-               off_t offset);
+// WriteAll writes data at specified offset, but it modifies file position.
+bool WriteAll(const FileDescriptorPtr& fd,
+              const void* buf,
+              size_t count,
+              off_t off);
 
 // Calls read() repeatedly until |count| bytes are read or EOF or EWOULDBLOCK
 // is reached. Returns whether all read() calls succeeded (including EWOULDBLOCK
@@ -81,11 +83,12 @@
 bool PReadAll(
     int fd, void* buf, size_t count, off_t offset, ssize_t* out_bytes_read);
 
-bool PReadAll(const FileDescriptorPtr& fd,
-              void* buf,
-              size_t count,
-              off_t offset,
-              ssize_t* out_bytes_read);
+// Reads data at specified offset, this function does change file position.
+bool ReadAll(const FileDescriptorPtr& fd,
+             void* buf,
+             size_t count,
+             off_t offset,
+             ssize_t* out_bytes_read);
 
 // Opens |path| for reading and appends its entire content to the container
 // pointed to by |out_p|. Returns true upon successfully reading all of the
diff --git a/payload_consumer/extent_reader.cc b/payload_consumer/extent_reader.cc
index ad983ae..3c7329d 100644
--- a/payload_consumer/extent_reader.cc
+++ b/payload_consumer/extent_reader.cc
@@ -77,7 +77,7 @@
         std::min(count - bytes_read, cur_extent_bytes_left);
 
     ssize_t out_bytes_read;
-    TEST_AND_RETURN_FALSE(utils::PReadAll(
+    TEST_AND_RETURN_FALSE(utils::ReadAll(
         fd_,
         bytes + bytes_read,
         bytes_to_read,
diff --git a/payload_consumer/mount_history.cc b/payload_consumer/mount_history.cc
index 43a75b3..1d2ec76 100644
--- a/payload_consumer/mount_history.cc
+++ b/payload_consumer/mount_history.cc
@@ -37,7 +37,7 @@
   brillo::Blob block0_buffer(kBlockSize);
   ssize_t bytes_read;
 
-  if (!utils::PReadAll(
+  if (!utils::ReadAll(
           blockdevice_fd, block0_buffer.data(), kBlockSize, 0, &bytes_read)) {
     LOG(WARNING) << "PReadAll failed";
     return;
diff --git a/payload_consumer/partition_writer.cc b/payload_consumer/partition_writer.cc
index bdc6015..12b206e 100644
--- a/payload_consumer/partition_writer.cc
+++ b/payload_consumer/partition_writer.cc
@@ -351,7 +351,7 @@
     for (uint64_t offset = 0; offset < length; offset += zeros.size()) {
       uint64_t chunk_length =
           std::min(length - offset, static_cast<uint64_t>(zeros.size()));
-      TEST_AND_RETURN_FALSE(utils::PWriteAll(
+      TEST_AND_RETURN_FALSE(utils::WriteAll(
           target_fd_, zeros.data(), chunk_length, start + offset));
     }
   }
diff --git a/payload_consumer/vabc_partition_writer.cc b/payload_consumer/vabc_partition_writer.cc
index 73bf413..e8994b4 100644
--- a/payload_consumer/vabc_partition_writer.cc
+++ b/payload_consumer/vabc_partition_writer.cc
@@ -115,11 +115,11 @@
         break;
       case CowOperation::CowReplace:
         ssize_t bytes_read = 0;
-        TEST_AND_RETURN_FALSE(utils::PReadAll(source_fd,
-                                              buffer.data(),
-                                              block_size,
-                                              cow_op.src_block * block_size,
-                                              &bytes_read));
+        TEST_AND_RETURN_FALSE(utils::ReadAll(source_fd,
+                                             buffer.data(),
+                                             block_size,
+                                             cow_op.src_block * block_size,
+                                             &bytes_read));
         if (bytes_read <= 0 || static_cast<size_t>(bytes_read) != block_size) {
           LOG(ERROR) << "source_fd->Read failed: " << bytes_read;
           return false;
diff --git a/payload_generator/cow_size_estimator.cc b/payload_generator/cow_size_estimator.cc
index 662a3ca..3eb0aca 100644
--- a/payload_generator/cow_size_estimator.cc
+++ b/payload_generator/cow_size_estimator.cc
@@ -39,11 +39,11 @@
     // No need to read from payload.bin then decompress, just read from target
     // directly.
     ssize_t bytes_read = 0;
-    auto success = utils::PReadAll(target_fd,
-                                   buffer.data(),
-                                   buffer.size(),
-                                   extent.start_block() * block_size,
-                                   &bytes_read);
+    auto success = utils::ReadAll(target_fd,
+                                  buffer.data(),
+                                  buffer.size(),
+                                  extent.start_block() * block_size,
+                                  &bytes_read);
     CHECK(success);
     CHECK_EQ(static_cast<size_t>(bytes_read), buffer.size());
     writer->AddRawBlocks(extent.start_block(), buffer.data(), buffer.size());