Method and apparatus for enabling adaptive endianness

• US 7,533,225 B1
• Filed: 08/17/2004
• Issued: 05/12/2009
• Est. Priority Date: 08/17/2004
• Status: Active Grant

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Ahrens, Matthew A., Bonwick, Jeffrey S., Moore, William H.
• Primary Examiner(s): Bragdon; Reginald G.
• Assistant Examiner(s): Mackall; Larry T
• Application Number:
  US10/919,886
• Time in Patent Office: 1,729 Days
• Field of Search: None
• US Class Current: 711/156
• CPC Class Codes: G06F 13/4027 using bus bridges G06F13/4022 takes precedence

Abstract

A method for reading a block, involving receiving a request to obtain the block, wherein the request comprises a block pointer, determining a block endianness by reading an endianness bit, obtaining the block using the block pointer, and byte-swapping data in the block to obtain a byte-swapped block, if a host endianness does not match the block endianness.

Claims

1. A method for writing a block comprising:

receiving a request to write a first data block and a second data block;

allocating a first space in a storage pool to store the first data block and a second space in the storage pool to store the second data block in response to the request, wherein the storage pool comprises at least one physical disk;

writing the first data block to the first space;

generating a first block pointer referencing the first data block, wherein the first block pointer comprises a first endianness bit associated with the first data block, and wherein the first block pointer is stored in a first indirect block;

setting the endianness bit for the first data block based on a first host endianness;

writing the second data block to the second space;

generating a second block pointer referencing the second data block, wherein the second block pointer comprises a second endianness bit associated with the second data block, and wherein the second block pointer is stored in the first indirect block; and

setting the endianness bit for the second data block based on a second host endianness, wherein the endianness indicated by the first endianness bit is different from the endianness indicated by the second endianness bit,

wherein the first data block, the second data block, and the first indirect block are each located in physically separate locations in the storage pool.

2. The method of claim 1, wherein the first endianness bit is located in a disk virtual address within the first block pointer, and wherein the second endianness bit is located in a disk virtual address within the second block pointer.

3. The method of claim 1, wherein the first host endianness is an endian scheme used by a first host writing the first data block, and wherein the second host endianness is an endian scheme used by a second host writing the second data block.

4. The method of claim 3, wherein the first host endianness is obtained by querying the first host, and wherein the second host endianness is obtained by querying the second host.

5. The method of claim 1, further comprising:

generating a third block pointer comprising a first indirect block checksum, a first indirect block location and a third endianness bit associated with the first indirect block, wherein the third block pointer is stored in a second indirect block that references the first indirect block.

6. A system, comprising:

a storage pool comprising at least one physical disk configured to store a first data block, a second data block, and a first indirect block,

wherein the first indirect block comprises a first block pointer referencing the first data block, wherein the first block pointer comprises a first data block checksum, a first endianness bit, and a first data block location, and a second block pointer referencing the second data block, wherein the second block pointer comprises a second data block checksum, a second endianness bit, and a second data block location,

wherein the endianness indicated by the first endianness bit associated with the first data block is different from the endianness indicated by the second endianness bit associated with the second data block; and

a storage pool allocator configured to store the first data block, the second data block, and the first indirect block, in the storage pool,

wherein the first data block, the second data block, and the first indirect block are each located in physically separate locations in the storage pool.

7. The system of claim 6, wherein the first endianness bit indicates the endianness of a first host that wrote the first data block and wherein the second endianness bit indicates the endianness of a second host that wrote the second data block.

8. The system of claim 6, wherein the first endianness bit is located in a disk virtual address within the first block pointer and wherein the second endianness bit is located in a disk virtual address within the second block pointer.

9. The system of claim 6, wherein the at least one physical disk in the storage pool is further configured to store a second indirect block, wherein the second indirect block comprises a third block pointer that references the first indirect block, and wherein the third block pointer comprises a first indirect block location, a first indirect block checksum, and a first indirect block endianness bit that indicates the endian scheme used to store the first indirect block.

10. A storage pool comprising a file system, wherein the file system comprises:

a plurality of child blocks, wherein the plurality of child blocks comprise

a plurality of data blocks, and

a plurality of indirect blocks, wherein each indirect block references

at least one of the plurality of child blocks;

a root block referencing at least one of the plurality of child blocks,

wherein the root block comprises a root checksum obtained using at least one of the plurality of child blocks,

wherein at least one of the indirect blocks comprises a first block pointer referencing a first child block and a second block pointer referencing a second child block, wherein the first block pointer comprises a first endianness bit associated with the first child block and a first child block checksum and the second block pointer comprises a second endianness bit associated with the second child block and a second child block checksum;

wherein the endianness indicated by the first endianness bit associated with the first child block is different from the endianness indicated by the second endianness bit associated with the second child block; and

a storage pool allocator configured to store the root block and the plurality of child blocks on at least one physical disk in the storage pool, wherein the first child block, the second child block, and the at least one of the indirect blocks are each located in physically separate locations in the storage pool.

11. The storage pool of claim 10, wherein the first endianness bit indicates the endianness of a first host that wrote the first child block and the second endianness bit indicates the endianness of a second host that wrote the second child block.

12. The storage pool of claim 10, wherein the first endianness bit is located in a disk virtual address within a corresponding indirect block and the second endianness bit is located in a disk virtual address within the corresponding indirect block.

13. A computer system for writing a block comprising:

a processor;

a memory;

a storage device; and

software instructions stored in the memory for enabling the computer system under control of the processor, to;

receive a request to write a first data block and a second data block;

allocate a first space in a storage pool to store the first data block and a second space in the storage pool to store the second data block in response to the request, wherein the storage pool comprises at least one physical disk;

write the first data block to the first space;

generate a first block pointer referencing the first data block, wherein the first block pointer comprises a first endianness bit associated with the first data block, and wherein the first block pointer is stored in an indirect block;

set the endianness bit for the first data block based on a first host endianness;

write the second data block to the second space;

generate a second block pointer referencing the second data block, wherein the second block pointer comprises a second endianness bit associated with the second data block, and wherein the second block pointer is stored in the indirect block; and

set the endianness bit for the second data block based on a second host endianness, wherein the endianness indicated by the first endianness bit is different from the endianness indicated by the second endianness bit,

wherein the first data block, the second data block, and the indirect block are each located in physically separate locations in the storage pool.

14. The computer system of claim 13, wherein the first endianness bit is located in a disk virtual address within the first block pointer and the second endianness bit is located in a disk virtual address within the second block pointer.

15. The computer system of claim 13, wherein the first host endianness is the endian scheme used by a first host writing the first data block and the second host endianness is the endian scheme used by a second host writing the second data block.

16. The computer system of claim 13, wherein the computer system is further configured to:

generate a third block pointer comprising a first indirect block checksum, a first indirect block location and a third endianness bit that indicates the endian scheme used to store the first indirect block, wherein the third block pointer is stored in a second indirect block that references the first indirect block.

17. A computer readable storage medium for writing a block comprising software instructions to:

receive a request to write a first data block and a second data block;

allocate a first space in a storage pool to store the first data block and a second space to store the second data block in the storage pool in response to the request, wherein the storage pool comprises at least one physical disk;

write the first data block to the first space;

generate a first block pointer referencing the first data block, wherein the first block pointer comprises a first endianness bit associated with the first data block, and wherein the first block pointer is stored in an indirect block comprising a plurality of block pointers;

set the endianness bit for the first data block based on a first host endianness;

write the second data block to the second space;

generate a second block pointer referencing the second data block, wherein the second block pointer comprises a second endianness bit associated with the second data block, and wherein the second block pointer is stored in the indirect block; and

set the endianness bit for the second data block based on a second host endianness, wherein the endianness indicated by the first endianness bit is different from the endianness indicated by the second endianness bit,

wherein the first data block, the second data block, and the indirect block are each located in physically separate locations in the storage pool.

18. A network system having a plurality of nodes comprising:

a storage pool comprising a first data block, a second data block, and an indirect block,

wherein the indirect block comprises a first block pointer referencing the first data block and a second block pointer referencing the second data block, wherein the first block pointer comprises a first data block checksum, a first endianness bit, and a first data block location and the second block pointer comprises a second data block checksum, a second endianness bit and a second data block location,

wherein the endianness indicated by the first endianness bit is different from the endianness indicated by the second endianness bit; and

a storage pool allocator configured to store the data block and the indirect block in at least one physical disk in the storage pool,

wherein the storage pool resides on any one of the plurality of nodes,

wherein the storage pool allocator resides on any one of the plurality of nodes,

wherein the first data block, the second data block, and the indirect block are each located in physically separate locations in the storage pool.