Techniques for managing data which is accessible by multiple storage processors

1. A method of managing storage, comprising:

in response to obtaining, at a first storage processor, an access request for a storage unit, determining whether the storage unit is currently accessible, the storage unit including at least one storage area;

in response to the storage unit being currently inaccessible, determining whether the first storage processor has an access right to the storage unit; and

in response to the first storage processor having no access right, requesting a second storage processor for the access right, the second storage processor being associated with a mirror storage unit of the storage unit, and the first and second storage processors having exclusive write access rights;

wherein a current accessibility indicator indicates whether the storage unit is currently accessible, and an access right indicator indicates the access right, the method further comprising:

in response to the storage unit being currently accessible, accessing the storage unit;

in response to the accessing of the storage unit being completed, determining whether the access request is a write access request;

in response to the access request being the write access request, updating the current accessibility indicator based on the write access request; and

obtaining from a waiting queue a request to be executed.

2. The method according to claim 1 , further comprising:

adding the access request into the waiting queue to wait to be executed.

3. The method according to claim 1 , further comprising:

in response to the first storage processor having the access right, adding the access request into the waiting queue to wait to be executed.

4. The method according to claim 1 , wherein determining whether the storage unit is currently accessible comprises:

updating the current accessibility indicator based on the access request; and

determining whether the storage unit is currently accessible.

5. The method according to claim 1 , the method further comprising:

in response to receiving, from the second storage processor, another response indicating that the access right is granted, updating the current accessibility indicator and the access right indicator based on the other response; and

obtaining from the waiting queue another request to be executed.

6. The method according to claim 1 , wherein the access request is a write access request, and requesting the second storage processor for the access right in response to the first storage processor having no access right comprises:

in response to the first storage processor having no write access right, writing data to be written into a temporary storage unit associated with the storage unit, the temporary storage unit including at least one temporary storage area, and the data to be written being obtained at the first storage processor;

requesting the second storage processor for the write access right; and

sending the data to be written to the second storage processor.

7. The method according to claim 1 , wherein the access request is a write access request, the method further comprising:

in response to the storage unit being currently write-accessible, writing data in a temporary storage unit associated with the storage unit into the storage unit, the temporary storage unit including at least one temporary storage area.

8. The method according to claim 1 , further comprising:

in response to the access request not being the write access request, determining whether there is existing a read access request for the storage unit;

in response to absence of the read access request for the storage unit, updating the current accessibility indicator based on the access right indicator; and

obtaining from the waiting queue the request to be executed.

9. The method according to claim 1 , wherein the first and second storage processors form at least part of a storage system; and

wherein the method further comprises:

receiving, as the access request for the storage unit, a data transmission request from a host which serves as a front end device to the storage system.

10. A method of managing storage, comprising:

in response to obtaining, at a first storage processor, a request for an access right to a storage unit of the first storage processor from a second storage processor, determining whether to permit the access right requested by the second storage processor to be granted or not currently, the storage unit including at least one storage area, the second storage processor being associated with a mirror storage unit of the storage unit, and the first and second storage processors having exclusive write access rights;

in response to permitting the requested access right to be granted, updating an access right indicator based on the request, the access right indicator indicating an access right of the first storage processor to the storage unit; and

sending, to the second storage processor, a response indicating that the requested access right is granted;

wherein a current accessibility indicator indicates whether the storage unit is currently accessible, the method further comprising:

in response to the storage unit being currently accessible, accessing the storage unit;

in response to the accessing of the storage unit being completed, determining whether the access request is a write access request;

in response to the access request being the write access request, updating the current accessibility indicator based on the write access request; and

obtaining from a waiting queue a request to be executed.

11. The method according to claim 10 , further comprising:

in response to preventing the requested access right from being granted, adding the request into the waiting queue to wait to be executed.

12. The method according to claim 10 , wherein the request is a request for a write access right, the method further comprising:

writing data to be written into a temporary storage unit associated with the storage unit, the temporary storage unit including at least one temporary storage area, and the data to be written being obtained at the first storage processor.

13. The method according to claim 12 , wherein updating an access right indicator based on the request in response to permitting the requested access right to be granted comprises:

in response to permitting the requested write access right to be granted, writing the data to be written from the temporary storage unit into the storage unit; and

updating the access right indicator based on the requested write access right.

14. A device for managing storage, comprising:

at least a processing unit; and

at least one memory coupled to the at least one processing unit and storing instructions executed by the at least one processing unit, the instructions, when executed by the at least one processing unit, causing the device to perform acts including:

in response to obtaining, at a first storage processor, an access request for a storage unit, determining whether the storage unit is currently accessible, the storage unit including at least one storage area;

in response to the storage unit being currently inaccessible, determining whether the first storage processor has an access right to the storage unit; and

in response to the first storage processor having no access right, requesting a second storage processor for the access right, the second storage processor being associated with a mirror storage unit of the storage unit, and the first and second storage processors having exclusive write access rights;

wherein a current accessibility indicator indicates whether the storage unit is currently accessible, and an access right indicator indicates the access right; and

wherein the acts further include:

in response to the storage unit being currently accessible, accessing the storage unit;

in response to the accessing of the storage unit being completed, determining whether the access request is a write access request;

in response to the access request being the write access request, updating the current accessibility indicator based on the write access request; and

obtaining from a waiting queue a request to be executed.

15. The device according to claim 14 , wherein the acts further include:

adding the access request into a waiting queue to wait to be executed.

16. The device according to claim 14 , wherein the acts further include:

in response to the first storage processor having the access right, adding the access request into the waiting queue to wait to be executed.

17. The device according to claim 14 , wherein determining whether the storage unit is currently accessible comprises:

updating the current accessibility indicator based on the access request; and

determining whether the storage unit is currently accessible.

18. The device according to claim 14 , wherein the acts further include:

in response to receiving, from the second storage processor, another response indicating that the access right is granted, updating the current accessibility indicator and the access right indicator based on the other response; and

obtaining from the waiting queue another request to be executed.

19. The device according to claim 14 , wherein the access request is a write access request, and requesting the second storage processor for the access right in response to the first storage processor having no access right comprises:

in response to the first storage processor having no write access right, writing data to be written into a temporary storage unit associated with the storage unit, the temporary storage unit including at least one temporary storage area, and the data to be written being obtained at the first storage processor;

requesting the second storage processor for the write access right; and

sending the data to be written to the second storage processor.

20. The device according to claim 14 , wherein the access request is a write access request, and the acts further include:

in response to the storage unit being currently write-accessible, writing data in a temporary storage unit associated with the storage unit into the storage unit, the temporary storage unit including at least one temporary storage area.