Common Block Storage Infrastructure

• US 20090327367A1
• Filed: 06/26/2008
• Published: 12/31/2009
• Est. Priority Date: 06/26/2008
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Tipton, William R., Mehra, Karan, Moss, Darren G., Brender, Scott A.
• Granted Patent: US 8,560,578 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0643 Management of files
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/0673 Single storage device

Abstract

Common block storage infrastructure techniques are described in which files are created through interaction with a file system to reserve extents in a volume on behalf of volume storage drivers, which may form a driver stack that resides logically on top of the volume. The files protect the reserved extents within the volume for use by the volume storage drivers, such as to store metadata related to operations performed by the drivers. When reserved extents are created, a location of the reserved extents is communicated through the driver stack to a corresponding volume storage driver. Volume storage drivers may also be configured to discover their corresponding reserved extents and communicate these to upper-level drivers and components. Accordingly, when a volume storage driver manipulates data in the volume, it may do so with awareness of the reserved extents of the other volume storage drivers.

Claims

1. One or more computer-readable media storing instructions executable by a computing device to:

receive a request from an application to allocate reserved extents on a volume owned by a file system for one of a plurality of volume storage drivers;

interact with the file system to cause allocation of the reserved extents in accordance with a common block storage infrastructure; and

communicate the allocation of the reserved extents to the plurality of volume storage drivers.

2. One or more computer-readable media as recited in claim 1, wherein the instructions are further executable to:

expose a first interface operable by the application to request the allocation of the reserved extents; and

expose a second interface operable to communicate the allocation of the reserved extents to the plurality of volume storage drivers.

3. One or more computer-readable media as recited in claim 2, wherein the common block storage infrastructure defines a plurality of rules to ensure coordination with the file system and to coordinate the reserved extents between the plurality of volume drivers.

4. One or more computer-readable media as recited in claim 1, wherein the instructions are further executable to:

request records from each of the plurality of volume storage drivers that describe corresponding reserved extents;

receive the requested records from the plurality of volume storage drivers; and

create files via the file system to protect the corresponding reserved extents described by the received records.

5. One or more computer-readable media as recited in claim 1, wherein allocation of the reserved extents includes creating one or more files through the file system to protect the reserved extents and creating handles to pin locations of the files in the volume.

6. One or more computer-readable media as recited in claim 5, wherein the instructions are further executable to close the one or more files and release the handles to pin the locations of the files when the file system dismounts the volume.

7. One or more computer-readable media as recited in claim 5, wherein the instructions are further executable to close the one or more files and release the handles to pin the locations of the files when the file system locks the volume.

8. One or more computer-readable media as recited in claim 1, wherein the plurality of volume storage drivers are configured to form a driver stack between the file system and the volume.

9. One or more computer-readable media as recited in claim 1, wherein communicate the allocation of the reserved extents comprises sending an input output control (IOCTL) command to the plurality of volume storage drivers.

10. A method comprising:

instantiating a volume storage driver to transform data on a volume that is owned by a file system;

reserving extents on the volume according to common block storage infrastructure (CBSI) rules to coordinate with the file system; and

coordinating the reserved extents with one or more other volume storage drivers according to the CBSI rules.

11. A method as recited in claim 10, wherein coordinating the reserved extents with the one or more other volume storage drivers further comprises:

notifying an upper-level driver of said one or more other storage drivers of the reserved extents corresponding to the volume storage driver;

maintaining by the volume storage driver of a list of reserved extents to provide in response to a query from the upper-level driver;

querying by the volume storage driver of a lower-level driver of said one or more other volume storage drivers to determine excluded extents; and

building a list of the excluded extents determined through the querying.

12. A method as recited in claim 10, wherein coordinating the reserved extents with the one or more other storage drivers according to the CBSI rules includes virtualizing a boot sector of the volume to an upper-level driver of said one or more other storage drivers when a boot sector read from a lower-level driver of said one or more other storage drivers is in an expected format.

13. A method as recited in claim 10, wherein reserving extents includes:

creating files through the file system to protect the reserved extents in the volume; and

pinning the files to prevent the file system from moving locations of files on the volume.

14. A method as recited in claim 10, wherein reserving extents according to common block storage infrastructure (CBSI) rules includes:

storing a location of the reserved extents to enable discovery by the volume storage driver;

modifying a boot sector of the volume to prevent mounting of the volume by a down-level operating system; and

virutalizing an unmodified version of the boot sector to the one or more other storage drivers to enable the file system to obtain the unmodified version of the boot sector.

15. A method as recited in claim 14, wherein storing a location of the reserved extents includes storing pointers to the reserved extents in a primary table on the volume and configuring the modified boot sector to include pointers to the primary table.

16. A method as recited in claim 10, wherein to coordinate the reserved extents with the one or more other volume storage drivers, the volume storage driver is configured to:

discover reserved extents that are allocated to the volume storage driver when the volume storage driver is instantiated; and

notify the one or more other volume storage drivers of the discovered reserved extents.

17. A computing device comprising:

a processor;

memory;

a volume defined in the memory;

an operating system to implement a file system for the volume; and

a plurality of drivers configured to;

form a driver stack between the volume and the file system;

store metadata to enable operations on the volume in reserved extents each corresponding to one of the plurality of drivers;

discover the reserved extents on the volume to retrieve the metadata; and

communicate one to another to coordinate the reserved extents between the plurality of drivers.

18. A computing device as recited in claim 17, wherein to coordinate the reserved extents between the plurality of drivers, each driver of said plurality of drivers is configured to:

maintain a list of said corresponding reserved extents of the driver;

discover the corresponding reserved extents when the driver stack is formed;

notify upper-level said drivers in the driver stack of the corresponding reserved extents; and

query lower-level said drivers in the driver stack to receive notification of said reserved extents corresponding to the lower-level said drivers.

19. A computing device as recited in claim 17, wherein the plurality of drivers are further configured to virtualize a boot sector of the volume successively up the driver stack to the file system.

20. A computing device as recited in claim 17, further comprising a common block storage infrastructure module stored in the memory and executable via the processor to:

receive requests to from applications of the computing device to allocate the reserved extents in the volume for the plurality of drivers;

interact with the file system to cause allocation of the reserved extents; and

communicate the allocation of the reserved extents to the plurality of drivers.