Fast and efficient method for deleting very large files from a filesystem

• US 20080005205A1
• Filed: 10/06/2006
• Published: 01/03/2008
• Est. Priority Date: 06/30/2006
• Status: Active Grant

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Rajakarunanayake, Yasantha Nirmal
• Granted Patent: US 7,765,244 B2
• Time in Patent Office: Days
• US Class Current: 707/205
• CPC Class Codes: G06F 16/162 Delete operations erasing in storage systems G06F3/0652

Abstract

In the current invention, a method and apparatus for efficiently deleting large files is described. This is done by having a special inode for pointing to data blocks to be freed, and subsequently freeing the data blocks from the special inode in a controlled manner.

Claims

1. An apparatus for deleting data files from a memory, the apparatus comprising:

a CPU; and

a memory, comprising;

a plurality of data blocks;

a plurality of inodes;

a plurality of files, wherein each of the plurality of files is associated with one or more of the plurality of data blocks and with one of the plurality of inodes; and

a garbage collection inode;

wherein the CPU is operable to delete one of the plurality of files from the memory by copying the address of the plurality of data blocks associated with the one of the plurality of files to be deleted from the inode associated with the one of the plurality of files to be deleted to the garbage collection inode.

2. The apparatus of claim 1, wherein the CPU is operable to traverse the garbage collection inode and free the plurality of data blocks associated with the one of the plurality of files to be deleted.

3. The apparatus of claim 1, wherein each of the plurality of files comprises a video feed.

4. The apparatus of claim 1, further comprising:

a tuner, wherein the tuner transmits a video feed to the CPU, and wherein the CPU is operable to store the video feed as a file.

5. The apparatus of claim 2, wherein the CPU is operable to perform additional operations while the operation of traversing the garbage collection inode and freeing the plurality of data blocks associated with the one of the plurality of files to be deleted occurs in the background.

6. The apparatus, as set forth in claim 1, wherein the memory comprises a fixed recording medium.

7. The apparatus, as set forth in claim 6, wherein the fixed recording medium comprises a hard disk drive.

8. A method for deleting a file in a memory, the method comprising:

(a) selecting a first inode representing the file to be deleted;

(b) designating a second inode as a garbage collection inode, wherein the garbage collection inode only points to files to be deleted;

(c) copying the address representing the location of a list of pointers to data blocks that compose the file to be deleted from the first inode to the garbage collection inode;

(d) zeroing the inode; and

(e) iterating through the list of pointers in the garbage collection inode and freeing the data blocks associated with each of the pointers in the list of pointers.

9. The method as set forth in claim 8, wherein step (c) comprises:

copying an indirect block pointer within the inode to an indirect block pointer within the garbage collection inode, wherein the indirect block pointer points to an indirect block comprising a list of pointers to a contiguous set of blocks of a first block size totaling a second block size.

10. The method as set forth in claim 9, wherein step (c) further comprises:

copying a doubly indirect block pointer within the inode to a doubly indirect block pointer within the garbage collection inode, wherein the doubly indirect block pointer points to a doubly indirect block comprising a list of pointers to a set of indirect blocks, the set of indirect blocks comprising a list of pointers to a contiguous set of blocks of the first block size totaling a third block size.

11. A computer program product comprising a computer usable medium having computer program logic recorded thereon for enabling a processor to delete a file in memory, the computer program logic comprising:

selecting means for enabling a processor to select an inode representing the file to be deleted;

copying means for enabling a processor to copy the address representing the location of a list of pointers to data blocks that compose the file to be deleted from the inode to a garbage collection inode; and

deletion means for enabling a processor to delete the file in the garbage collection inode.