Increasing efficiency of data storage in a file system

• US 8,521,790 B2
• Filed: 11/04/2009
• Issued: 08/27/2013
• Est. Priority Date: 10/30/2003
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Best, Steven F., Cooper, Michael R.
• Primary Examiner(s): PHILLIPS, III, ALBERT M
• Application Number:
  US12/612,457
• Publication Number:
  US 20100049755A1
• Time in Patent Office: 1,392 Days
• Field of Search: 707/609, 707/687, 707/821, 707/822, 714/4.4
• US Class Current: 707/822
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0643 Management of files
• CPC Class Codes: G06F 3/0674 Disk device

Abstract

A method, apparatus, and computer instructions for storing data in a file system. A determination is made as to whether space is available in an inode of the file in the file system. The data is stored into the inode in response to space being available. Additionally, data for a file may be stored in a block that is partially filled with data from another file. Data for a file may be stored using either the inode or by sharing a block. Data also may be stored using both of these mechanisms.

Claims

1. A method in a data processing system, the method comprising:

receiving a command to store a file in a file system having an inode, wherein the inode is usable to store metadata associated with the file;

responsive to the file having a size that is greater than a block size of blocks in the file system, storing a plurality of data of the file only in an integer number of blocks, wherein a first remainder data of the file remains after storing, and wherein the first remainder data is less than the block size;

determining whether space is available in the inode; and

responsive to space being available in the inode, placing the first remainder data directly into the inode.

2. The method of claim 1 further comprising:

determining whether a second remainder data of the file is present after the first remainder data is placed into the inode; and

responsive to the second remainder data being present, storing the second remainder data in a partially filled block associated with another file, wherein the partially filled block also stores data of the another file.

3. The method of claim 2 further comprising:

responsive to the partially used block becoming full from storing the second remainder data in the partially used block, removing the partially used block from a list of free shared blocks, wherein, for each free shared block on the list of free shared blocks, the list of free shared blocks contains a block number, a free byte quantity, and a pointer to a next free shared block.

4. The method of claim 3, wherein the partially filled block is a last block associated with the another file.

5. The method of claim 1, wherein the data is placed into an extension area of the inode.

6. The method of claim 1 further comprising:

indicating that data is stored in the inode.

7. The method of claim 1 further comprising:

determining whether placing the data in the inode was successful.

8. The method of claim 6 wherein indicating is performed by updating a flag.

9. The method of claim 2 further comprising:

using pointers to point to the partially filled block, wherein the pointers are included in the inode.

10. A recordable-type computer readable medium a computer program product encoded thereon executable in a data processing system, the computer program product comprising:

instructions for receiving a command to store a file in a file system having an inode, wherein the inode is usable to store metadata associated with the file;

instructions for responsive to the file having a size that is greater than a block size of blocks in the file system, storing a plurality of data of the file only in an integer number of blocks, wherein a first remainder data of the file remains after storing, and wherein the first remainder data is less than the block size;

instructions for determining whether space is available in the inode; and

instructions for, responsive to space being available in the inode, placing the first remainder data directly into the inode.

11. The recordable-type computer readable medium of claim 10, the computer program product further comprising:

instructions for determining whether a second remainder data of the file is present after the first remainder data is placed into the inode; and

instructions, responsive to the second remainder data being present, for storing the second remainder data in a partially filled block associated with another file, wherein the partially filled block also stores data of the another file.

12. The recordable-type computer readable medium of claim 11, the computer program product further comprising:

instructions, responsive to the partially used block becoming full from storing the second remainder data in the partially used block, for removing the partially used block from a list of free shared blocks, wherein, for each free shared block on the list of free shared blocks, the list of free shared blocks contains a block number, a free byte quantity, and a pointer to a next free shared block.

13. The recordable-type computer readable medium of claim 12, wherein the partially filled block is a last block associated with the another file.

14. The recordable-type computer readable medium of claim 10, wherein the data is placed into an extension area of the inode.

15. The recordable-type computer readable medium of claim 10, the computer program product further comprising:

instructions for indicating that data is stored in the inode.

16. The recordable-type computer readable medium of claim 10, the computer program product further comprising:

instructions for determining whether placing the data in the inode was successful.

17. The recordable-type computer readable medium of claim 15, wherein indicating is performed by updating a flag.

18. The recordable-type computer readable medium of claim 11, the computer program product further comprising:

instructions for using pointers to point to the partially filled block, wherein the pointers are included in the inode.