GARBAGE COLLECTION PROGRAM, GARBAGE COLLECTION METHOD, AND GARBAGE COLLECTION SYSTEM

• US 20110113075A1
• Filed: 01/07/2011
• Published: 05/12/2011
• Est. Priority Date: 08/11/2008
• Status: Abandoned Application

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: FUKUSHIMA, Hirotaka
• Application Number:
  US12/986,515
• Publication Number:
  US 20110113075A1
• Time in Patent Office: Days
• US Class Current: 707/813
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/7205 Cleaning, compaction, garbage collection, erase control

Abstract

A computer-readable storage medium storing a garbage collection program allows a computer to execute: copying valid data from a first block in a first storage device to a second storage device; instructing an exclusive mechanism to perform exclusive control of accessing to the valid data in the first block; switching an access path to the valid data in the first block, to the valid data in the second storage device; instructing the exclusive mechanism to release the exclusive control; copying the valid data in the second storage device to a second block in the first storage device to collect; instructing the exclusive mechanism to perform exclusive control of accessing to the valid data in the second storage device; switching an access path to the valid data in the second storage device, to the valid data in the second block; and instructing the exclusive mechanism to release the exclusive control.

Claims

1. A non-transitory, computer-readable storage medium storing a garbage collection program allowing a computer to execute:

copying valid data from a first block in a first storage device that stores both valid data and invalid data to a second storage device different from the first storage device, data stored in the first storage device is deleted in a unit of block;

instructing an exclusive unit to perform exclusive control of accessing to the valid data in the first block;

switching, after the exclusive control is performed, an access path to the valid data in the first storage device to an access path to the valid data copied to the second storage device;

instructing, after the access path is switched to the access path to the valid data copied to the second storage device, the exclusive unit to release the exclusive control of accessing to the valid data in the first block when;

copying the valid data in the second storage device to a second block in the first storage device that is different from the first block to collect the valid data into the second block;

instructing the exclusive unit to perform exclusive control of accessing to the valid data in the second storage device;

switching, after the exclusive control is performed, an access path to the valid data in the second storage device to an access path to the valid data copied to the second block; and

instructing, after an access path is switched to the access path to the valid data copied to the second storage device, the exclusive unit to release the exclusive control of accessing the valid data in the second storage device.

2. The computer-readable storage medium according to claim 1, further allowing the computer to execute, setting a flag regard the valid data in the first block as the invalid data after the access path is switched to the access path to the valid data in the first block.

3. The computer-readable storage medium according to claim 1, further allowing the computer to execute, deleting the valid data copied to the second storage device after the exclusive unit releases the exclusive control of accessing to the valid data in the second storage device.

4. The computer-readable storage medium according to claim 1, further allowing the computer to execute, determining before copying the valid data in the first block to the second storage device, whether a target data is the valid data or the invalid data.

5. The computer-readable storage medium according to claim 4, wherein copying the valid data in the first block to the second storage device when it is determined that the target data is the valid data.

6. The computer-readable storage medium according to claim 4, wherein

processing of the garbage collection program is ended when it is determined that the target data is the invalid data.

7. The computer-readable storage medium according to claim 1, further allowing the computer to execute, determining, after copying the valid data in the first block to the second storage device, whether the valid data in the first block is still valid or not.

8. The computer-readable storage medium according to claim 7, allowing the computer to further execute, instructing the exclusive unit to perform exclusive control of accessing to the valid data in the first block when it is determined that the valid data in the first block is still valid.

9. The computer-readable storage medium according to claim 7, allowing the computer to further execute, deleting the valid data in the second storage device when it is determined that the valid data in the first block has become invalid.

10. The computer-readable storage medium according to claim 1, further allowing the computer to execute, determining, after copying the valid data in the second storage device to the second block, whether the valid data in the second storage device is still valid or not.

11. The computer-readable storage medium according to claim 10, allowing the computer to execute, instructing the exclusive unit to perform exclusive control of accessing to the valid data in the second storage device when it is determined that the valid data in the second storage device is still valid.

12. The computer-readable storage medium according to claim 10, further allowing the computer to further execute:

marking a flag regard the valid data in the second block as the invalid data when it is determined that the valid data in the second storage device has become invalid; and

deleting the valid data in the second storage device.

13. A garbage collection system comprising:

a first copy section that copies valid data from a first block in a first storage device contains both valid data and invalid data to a second storage device different from the first storage device, data stored in the first storage device is deleted in a unit of block;

a first exclusive instruction section that instructs an exclusive unit to perform exclusive control of accessing the valid data to be copied in the first block;

a first switch section that switches an access path to the valid data in the first block to be copied to an access path to the valid data copied to the second storage device after the exclusive control is instructed by the first exclusive instruction section;

a first exclusive release instruction section that instructs the exclusive unit to release the exclusive control after the first switch section switches the access path;

a second copy section that copies the valid data in the second storage device to a second block in the first storage device that is different from the first block;

a second exclusive instruction section that instructs the exclusive unit to perform exclusive control of accessing the valid data in the second storage device;

a second switch section that switches an access path to the valid data in the second storage device to an access path to the valid data copied to the second block after the exclusive control is instructed by the second exclusive instruction section; and

a second exclusive release instruction section that instructs the exclusive unit to release the exclusive control after the second switch section switches the access path.

14. The garbage collection system according to claim 13, characterized by further comprising, a first flag setting section that sets, after the first switch section switches the access path, a predetermined flag regard the valid data in the first block as the invalid data.

15. The garbage collection system according to claim 13, characterized by further comprising, a deletion section that deletes, after the exclusive unit releases the exclusive control by the second exclusive release instruction section, the valid data in the second storage device.

16. The garbage collection system according to claim 13, characterized by further comprising, a first determination section that determines, before the first copy section copies the valid data in the first block to the second storage device, whether a target data is the valid data or the invalid data.

17. The garbage collection system according to claim 13, characterized by further comprising, a second determination section that determines, after the first copy section copies the valid data in the first block to the second storage device, whether the valid data in the first block is still valid or not.

18. The garbage collection system according to claim 13, characterized by further comprising, a third determination section that determines, after the second copy section copies the valid data in the second storage device to the second block, whether the valid data in the second storage device is still valid or not.

19. A garbage collection method comprising:

copying valid data from a first block in a first storage device stores both valid data and invalid data to a second storage device different from the first storage device the valid data and invalid data being stored in the first block;

instructing an exclusive unit to perform exclusive control of accessing to the valid data in the first block;

switching an access path to the valid data in the first block to an access path to the valid data copied to the second storage device, after the instructed exclusive control is performed;

instructing the exclusive unit to release the exclusive control after the access path is switched;

copying the valid data copied in the second storage device to a second block in the first storage device that is different from the first block to collect the valid data;

instructing the exclusive unit to perform exclusive control of accessing to the valid data in the second storage device to be copied;

switching an access path to the valid data to be copied in the second storage device to an access path to the valid data copied to the second block when the exclusive control of accessing to the valid data in the second storage device to be copied is performed; and

instructing the exclusive unit to release the exclusive control after the switching of the access path is performed.

20. The garbage collection method according to claim 19, further comprising, setting, after the switching of the access path to the valid data in the first block, a predetermined flag regard the valid data in the first block as the invalid data.