Added method BlockSize() to get the block size of the underlying file system.

Untested but with good chances to actually work.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34106 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/os/storage/Volume.h

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2008, Haiku Inc. All Rights Reserved.
+ * Copyright 2002-2009, Haiku Inc. All Rights Reserved.
  * Distributed under the terms of the MIT License.
  */
 #ifndef _VOLUME_H
@@ -34,6 +34,7 @@ public:
 
 			off_t			Capacity() const;
 			off_t			FreeBytes() const;
+			off_t			BlockSize() const;
 
 			status_t		GetName(char* name) const;
 			status_t		SetName(const char* name);

src/kits/storage/Volume.cpp

@@ -232,6 +232,30 @@ BVolume::FreeBytes() const
 	return (error == B_OK ? info.free_blocks * info.block_size : error);
 }
 
+
+/*!	\brief Returns the size of one block (in bytes). It depends on the
+		underlying file system what this means exactly.
+	\return
+	- The block size in bytes.
+	- \c B_NO_INIT if the volume is not initialized.
+	- Other errors forwarded from the file system.
+*/
+off_t
+BVolume::BlockSize() const
+{
+	// check initialization
+	if (InitCheck() != B_OK)
+		return B_NO_INIT;
+
+	// get FS stat
+	fs_info info;
+	if (fs_stat_dev(fDevice, &info) != 0)
+		return errno;
+
+	return info.block_size;
+}
+
+
 // GetName
 /*!	\brief Returns the name of the volume.