Method, device, and computer readable storage medium for allocating access rights to data among storage processors
Embodiments of the present disclosure relate to a method, device and computer readable medium for managing storage. The method comprises: 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. The method further comprises: in response to the storage unit being currently inaccessible, determining whether the first storage processor has an access right to the storage unit. In addition, the method further comprises: 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.
1. A method of implementing unified management of a storage system, comprising:
in response to receiving, at a storage processor, an access request for a storage unit, determining whether the storage unit is currently accessible based on a value of a state from among three states of a current accessibility indicator, the three states of the current accessibility indicator including a currently inaccessible state, a currently read-accessible state, and a currently write-accessible state;
determining the state of the current accessibility indicator based on a value of a state from among three states of an access right indicator, the three states of the access right indicator including a no-access right state, a read-access right state, and a write-access right state, the three states of the current accessibility indicator and the three states of the access right indicator being configured to allocate an access right to the storage unit among two or more storage processors; and
performing one of accessing the storage unit and avoiding accessing the storage unit based on the determined state of the current accessibility indicator.
2. The method of claim 1 wherein the state of the access right indicator corresponds to the no-access right state, and wherein the determining of the state of the current accessibility indicator based on the state of the access right indicator includes determining that the state of the current accessibility indicator corresponds to the currently inaccessible state.
3. The method of claim 2 wherein the performing of one of accessing the storage unit and avoiding accessing the storage unit includes, having determined that the state of the current accessibility indicator corresponds to the currently inaccessible state, avoiding accessing the storage unit.
4. The method of claim 1 wherein the state of the access right indicator corresponds to the read-access right state, and wherein the determining of the state of the current accessibility indicator based on the state of the access right indicator includes determining that the state of the current accessibility indicator corresponds to one of (i) the currently read-accessible state, and (ii) the currently inaccessible state.
5. The method of claim 4 further comprising:
having determined that the state of the current accessibility indicator corresponds to the currently read-accessible state, determining that a current access request for the storage unit does not exist or at least one ongoing read-access of the storage unit exists.
6. The method of claim 5 wherein the performing of one of accessing the storage unit and avoiding accessing the storage unit includes, having determined that the state of the current accessibility indicator corresponds to the currently read-accessible state, read-accessing the storage unit.
7. The method of claim 4 further comprising:
having determined that the state of the current accessibility indicator corresponds to the currently inaccessible state, determining that at least one write-access request exists waiting to be executed.
8. The method of claim 7 wherein the performing of one of accessing the storage unit and avoiding accessing the storage unit includes, having determined that the state of the current accessibility indicator corresponds to the currently inaccessible state, avoiding accessing the storage unit.
9. The method of claim 1 wherein the state of the access right indicator corresponds to the write-access right state, and wherein the determining of the state of the current accessibility indicator based on the state of the access right indicator includes determining that the state of the current accessibility indicator corresponds to one of (i) the currently write-accessible state, (ii) the currently read-accessible state, and (iii) the currently inaccessible state.
10. The method of claim 9 further comprising:
having determined that the state of the current accessibility indicator corresponds to the currently write-accessible state, determining that a current access request for the storage unit does not exist.
11. The method of claim 10 wherein the performing of one of accessing the storage unit and avoiding accessing the storage unit includes, having determined that the state of the current accessibility indicator corresponds to the currently write-accessible state, write-accessing the storage unit.
12. The method of claim 9 further comprising:
having determined that the state of the current accessibility indicator corresponds to the currently read-accessible state, determining that at least one ongoing read-access of the storage unit exists.
13. The method of claim 12 wherein the performing of one of accessing the storage unit and avoiding accessing the storage unit includes, having determined that the state of the current accessibility indicator corresponds to the currently read-accessible state, read-accessing the storage unit.
14. The method of claim 9 further comprising:
having determined that the state of the current accessibility indicator corresponds to the currently inaccessible state, determining that at least one ongoing write-access of the storage unit exists.
15. The method of claim 14 wherein the performing of one of accessing the storage unit and avoiding accessing the storage unit includes, having determined that the state of the current accessibility indicator corresponds to the currently inaccessible state, avoiding accessing the storage unit.
16. The method of claim 9 further comprising:
having determined that the state of the current accessibility indicator corresponds to the currently inaccessible state, determining that at least one ongoing read-access of the storage unit exists and at least one write-access request exists waiting to be executed.
17. The method of claim 16 wherein the performing of one of accessing the storage unit and avoiding accessing the storage unit includes, having determined that the state of the current accessibility indicator corresponds to the currently inaccessible state, avoiding accessing the storage unit.
18. The method of claim 1 further comprising:
representing the value of the state from among the three states of the current accessibility indicator by two bits;
representing the value of the state from among the three states of the access right indicator by two bits; and
implementing an operation of the access right indicator and the current accessibility indicator with a bitmap.
19. A device for implementing unified management of a storage system, comprising:
a memory; and
a storage processor configured to execute program instructions out of the memory to:
in response to receiving an access request for a storage unit, determine whether the storage unit is currently accessible based on a value of a state from among three states of a current accessibility indicator, the three states of the current accessibility indicator including a currently inaccessible state, a currently read-accessible state, and a currently write-accessible state;
determine the state of the current accessibility indicator based on a value of a state from among three states of an access right indicator, the three states of the access right indicator including a no-access right state, a read-access right state, and a write-access right state, the three states of the current accessibility indicator and the three states of the access right indicator being configured to allocate an access right to the storage unit among two or more storage processors; and
perform one of accessing the storage unit and avoiding accessing the storage unit based on the determined state of the current accessibility indicator.
20. The device of claim 19 wherein the state of the access right indicator corresponds to the no-access right state, and wherein the storage processor is further configured to execute the program instructions out of the memory to:
determine that the state of the current accessibility indicator corresponds to the currently inaccessible state; and
having determined that the state of the current accessibility indicator corresponds to the currently inaccessible state, avoid accessing the storage unit.
21. A computer program product including a set of non-transitory, computer-readable media having program instructions that, when executed by a storage processor, cause the storage processor to perform a method comprising:
in response to receiving an access request for a storage unit, determining whether the storage unit is currently accessible based on a value of a state from among three states of a current accessibility indicator, the three states of the current accessibility indicator including a currently inaccessible state, a currently read-accessible state, and a currently write-accessible state;
determining the state of the current accessibility indicator based on a value of a state from among three states of an access right indicator, the three states of the access right indicator including a no-access right state, a read-access right state, and a write-access right state, the three states of the current accessibility indicator and the three states of the access right indicator being configured to allocate an access right to the storage unit among two or more storage processors; and
performing one of accessing the storage unit and avoiding accessing the storage unit based on the determined state of the current accessibility indicator.