I/O dependency graphs

1. A method for executing a selected input/output (I/O) command from a plurality of I/O commands based on a dependency graph of I/O commands, comprising:

building the dependency graph of I/O commands, wherein the dependency graph is built by requiring all children of the selected I/O command to be ready before the selected I/O command is ready; and

executing the I/O command based on the dependency graph, wherein execution of the selected I/O command is completed when all of the children of the selected I/O command finish execution.

2. The method of claim 1 , wherein the method for selecting an I/O command based on a dependency graph of I/O commands is used to facilitate the operation of a file system.

3. The method of claim 1 , wherein the plurality of I/O commands is selected and executed in parallel based on the dependency graph.

4. The method of claim 1 , wherein instructions for readying the selected I/O command are executed after all children of the selected I/O command are ready.

5. The method of claim 1 , wherein instructions for completing the selected I/O command are executed after all children of the selected I/O command are finished executing.

6. A system for executing a selected input/output (I/O) command from a plurality of I/O commands based on a dependency graph of I/O commands, comprising:

a file system configured to:

build the dependency graph of I/O commands, wherein the dependency graph is built by requiring all children of the selected I/O command to be ready before the selected I/O command is ready; and

execute the I/O command based on the dependency graph, wherein execution of the selected I/O command is completed when all of the children of the selected I/O command finish execution.

7. The system of claim 6 , further comprising the plurality of children of the selected I/O command based on the dependency graph of I/O commands.

8. The system of claim 6 , wherein the system for executing a selected I/O command based on a dependency graph of I/O commands is used to facilitate the operation of a file system.

9. The system of claim 6 , wherein the plurality of I/O commands is selected and executed in parallel based on the dependency graph.

10. The system of claim 6 , wherein the dependency graph of I/O commands comprises:

a plurality of I/O commands; and

a plurality of edges connecting the I/O commands.

11. The system of claim 10 , wherein the plurality of edges connecting the I/O dependencies comprise directed edges.

12. The system of claim 10 , wherein the dependency graph of I/O commands is mapped from a hierarchical data configuration for storing data blocks and indirect blocks in a file system.

13. A computer usable medium having computer readable program code embodied therein for causing a computer system for executing a method for executing a selected input/output (I/O) command from a plurality of I/O commands based on a dependency graph of I/O commands, comprising:

building the dependency graph of I/O commands, wherein the dependency graph is built by requiring all children of the selected I/O command to be ready before the selected I/O command is ready; and

executing the I/O command based on the dependency graph, wherein execution of the selected I/O command is completed when all of the children of the selected I/O command finish execution.

14. The computer usable medium of claim 13 , wherein the method for executing a selected I/O command based on a dependency graph of I/O commands is used to facilitate the operation of a file system.

15. The computer usable medium of claim 13 , wherein a plurality of I/O commands is selected and executed in parallel based on the dependency graph.

16. The computer usable medium of claim 13 , wherein instructions for readying the selected I/O command are executed after all children of the selected I/O command are ready.

17. The computer usable medium of claim 13 , wherein instructions for completing the selected I/O command are executed after all children of the selected I/O command are finished executing.