dev-util/stressapptest/files/0003-realign-buffers-for-4k-blocksize.patch

Make stressapptest somewhat reasonably handle native 4k blocksize.
It is a gross hack anyway because there is no way to make it nicer without
significant re-write of the logic.

diff --git a/src/worker.cc b/src/worker.cc
index c4abc87..d9a6487 100644
--- a/src/worker.cc
+++ b/src/worker.cc
@@ -2818,6 +2818,12 @@ bool DiskThread::GetDiskSize(int fd) {
       return false;
     }
 
+    if (ioctl(fd, BLKSSZGET, &logical_block_size_) == -1) {
+      logprintf(0, "Process Error: Unable to get block size for disk %s (thread %d).\n",
+                device_name_.c_str(), thread_num_);
+      return false;
+    }
+
     // Zero size indicates nonworking device..
     if (block_size == 0) {
       os_->ErrorReport(device_name_.c_str(), "device-size-zero", 1);
@@ -2830,6 +2836,7 @@ bool DiskThread::GetDiskSize(int fd) {
 
   } else if (S_ISREG(device_stat.st_mode)) {
     device_sectors_ = device_stat.st_size / kSectorSize;
+    logical_block_size_ = device_stat.st_blksize;
 
   } else {
     logprintf(0, "Process Error: %s is not a regular file or block "
@@ -2838,6 +2845,15 @@ bool DiskThread::GetDiskSize(int fd) {
     return false;
   }
 
+  if (write_block_size_ == kSectorSize) {
+    write_block_size_ = logical_block_size_;
+    queue_size_ = ((cache_size_ / write_block_size_) * 3) / 2;
+  }
+
+  if (read_block_size_ == kSectorSize) {
+    read_block_size_ = logical_block_size_;
+  }
+
   logprintf(12, "Log: Device sectors: %lld on disk %s (thread %d).\n",
             device_sectors_, device_name_.c_str(), thread_num_);
 
@@ -3235,10 +3251,10 @@ bool DiskThread::Work() {
   // Allocate a block buffer aligned to 512 bytes since the kernel requires it
   // when using direct IO.
 #ifdef HAVE_POSIX_MEMALIGN
-  int memalign_result = posix_memalign(&block_buffer_, kBufferAlignment,
+  int memalign_result = posix_memalign(&block_buffer_, logical_block_size_,
                                        sat_->page_length());
 #else
-  block_buffer_ = memalign(kBufferAlignment, sat_->page_length());
+  block_buffer_ = memalign(logical_block_size_, sat_->page_length());
   int memalign_result = (block_buffer_ == 0);
 #endif
   if (memalign_result) {
diff --git a/src/worker.h b/src/worker.h
index c96c04c..9491720 100644
--- a/src/worker.h
+++ b/src/worker.h
@@ -696,8 +696,6 @@ class DiskThread : public WorkerThread {
 
  protected:
   static const int kSectorSize = 512;       // Size of sector on disk.
-  static const int kBufferAlignment = 512;  // Buffer alignment required by the
-                                            // kernel.
   static const int kBlockRetry = 100;       // Number of retries to allocate
                                             // sectors.
 
@@ -728,6 +726,7 @@ class DiskThread : public WorkerThread {
   // Main work loop.
   virtual bool DoWork(int fd);
 
+  int logical_block_size_;   // Logical block size of the device.
   int read_block_size_;       // Size of blocks read from disk, in bytes.
   int write_block_size_;      // Size of blocks written to disk, in bytes.
   int64 blocks_read_;         // Number of blocks read in work loop.