File system migration

1. A method to perform file system migration, the method comprising:

associating a source block device to a destination block device, wherein the source block device and the destination block device include a plurality of source blocks and destination blocks, respectively;

directing at least one directed command for a source block from the plurality of source blocks to the source block device or the destination block device based at least on the associating and a file system update bitmap on the source block device;

computing a copy bitmap based on the file system update bitmap, wherein the copy bitmap indicates at least one block on the source block device has been allocated but has not been updated at the destination block device;

updating a destination block from the plurality of destination blocks based, in part, on the at least one directed command and the copy bitmap;

tracking an updated status associated with the destination block via the file system update bitmap on the source block device; and

copying a source block from the plurality of source blocks, associated with a destination block that has not been updated, to the destination block device.

2. The method as claimed in claim 1 , wherein the at least one directed command is generated during the file system migration.

3. The method as claimed in claim 1 , wherein the directing the at least one directed command further comprises subsequently directing the at least one directed command to the destination block associated with the source block when the at least one directed command is a write request.

4. The method as claimed in claim 1 , wherein the directing further comprises:

for the at least one directed command being a read request, subsequently directing the at least one directed command to the source block, if a corresponding destination block has not been updated; and

for the at least one directed command being the read request, subsequently directing the at least one directed command to another destination block from the plurality of destination blocks corresponding to the source block, when the another destination block has been updated.

5. A system for file system migration comprising:

a computing device including:

a processor;

a memory coupled to the processor, to

associate a source block device to a destination block device, wherein the source block device and the destination block device include a plurality of source blocks and destination blocks, respectively;

direct at least one directed command for a source block from the plurality of source blocks to the source block device or the destination block device based at least on the associating and a file system update bitmap on the source block device;

compute a copy bitmap based on the file system update bitmap, wherein the copy bitmap indicates at least one block on the source block device has been allocated but has not been updated at the destination block device;

update a destination block from the plurality of destination blocks based, in part, on the at least one directed command and the copy bitmap;

track the updated status associated with the destination block via the file system update bitmap on the source block device; and

copy a source block from the plurality of source blocks, associated with a destination block that has not been updated, to the destination block device.

6. The system as claimed in claim 5 , further comprising modifying the file system update bitmap to track updates to at least one block on the destination block device.

7. The system as claimed in claim 5 , further comprising modifying of the file system update bitmap when at least one block on the destination block device is updated.

8. The system as claimed in claim 5 , wherein computing the copy bitmap is also based on a destination allocation bitmap to indicate the at least one block on the source block device that has been allocated based on the destination allocation bitmap but has not been updated at the destination block device.

9. The system as claimed in claim 8 , wherein migrating a file system from the source block device to the destination block device is based on the copy bitmap.

10. A non-transitory computer-readable medium having a set of computer readable instructions that, when executed, perform acts comprising:

in response to at least one command for relocation of at least one block on a source block device, relocating the at least one block from the source block device to a destination block device based on an association between the source block device and the destination block device;

updating a file system update bitmap on the source block device in response to the relocating;

computing a copy bitmap based on the file system update bitmap, wherein the copy bitmap indicates at least one block on the source block device has been allocated but has not been updated at the destination block device;

copying at least one other block from the source block device to the destination block device based on the copy bitmap, wherein the at least one other block has not been relocated; and

tracking an updated destination block via the file system update bitmap on the source block device.

11. The non-transitory computer-readable medium as claimed in claim 10 , wherein the copying further includes computing a copy bitmap based on the file system update bitmap and a destination allocation bitmap.

12. The non-transitory computer readable medium as claimed in claim 10 , wherein the copying is based on a source allocation bitmap when none of the blocks of the source block device are updated.

13. The non-transitory computer readable medium as claimed in claim 10 , wherein the relocating comprises mapping the at least one block of the source block device to at least one block on the destination block device.

14. The non-transitory computer readable medium as claimed in claim 13 , wherein the relocating further comprises directing commands to the source block device for reading at least one block from the source block device based on the mapping, when the at least one block has not been updated at the destination block device.