Remotely mounted file system with stubs
Metadata of a root node from a serialized representation of a file system metadata tree data structure is obtained. A representation of the root node that references a stub intermediate node that is a placeholder for an intermediate node stored in the serialized representation is created. A request to access data of a leaf node in a tree path including the intermediate node is received. In response to the request, metadata of the intermediate node is obtained from serialized metadata representation.
1. A method, comprising:
receiving a request to access one or more files archived at a cloud storage;
obtaining metadata associated with the one or more requested files from a serialized representation of the metadata associated with the one or more requested files stored at the cloud storage, wherein the serialized representation of the metadata associated with the one or more requested files includes a first flat set of data comprised of a plurality of data blocks and a second flat set of data comprised of a second plurality of data blocks, wherein the first flat set of data corresponds to a first archive and the second flat set of data corresponds to a second archive, wherein a first data block of the first flat set of data includes a file offset to a second data block of the second flat set of data;
partially restoring, at a storage system, a file system metadata tree data structure based on the obtained metadata associated with the one or more requested files, wherein the partially restored file system metadata tree data structure includes one or more stub nodes associated with one or more non-requested files; and
providing access to the one or more requested files using the partially restored file system metadata tree data structure.
2. The method of claim 1 , wherein each of the first plurality of data blocks corresponds to a node included in the file system metadata tree data structure.
3. The method of claim 1 , wherein one of the first plurality of data blocks includes one or more file offsets to one or more other data blocks.
4. The method of claim 3 , wherein a file offset of the one or more file offsets references a data block of the one or more other data blocks that is included in the first flat set of data.
5. The method of claim 1 , wherein a stub node of the one or more stub nodes references a data block included in a flat set of data stored at the cloud storage.
6. The method of claim 1 , further comprising prefetching from the cloud storage metadata associated with the one or more non-requested files.
7. The method of claim 6 , further comprising replacing the one or more stub nodes associated with the one or more non-requested files with the prefetched metadata associated with the one or more non-requested files.
8. The method of claim 6 , wherein the metadata associated with the one or more non-requested files is prefetched based on a prior usage pattern.
9. The method of claim 1 , wherein the partially restored file system metadata tree data structure includes a corresponding restored path from a root node to a corresponding leaf node associated with each of the one or more requested files.
10. The method of claim 1 , wherein partially restoring the file system metadata tree data structure includes:
traversing the partially restored file system metadata tree data structure; and
replacing one or more stub nodes of the partially restored file system metadata tree data structure with the metadata associated with the one or more requested files.
11. The method of claim 1 , wherein the one or more files are archived to the cloud storage according to an archive policy.
12. A computer program product embodied in a non-transitory computer readable medium and comprising computer instructions for:
receiving a request to access one or more files archived at a cloud storage;
obtaining metadata associated with the one or more requested files from a serialized representation of the metadata associated with the one or more requested files stored at the cloud storage, wherein the serialized representation of the metadata associated with the one or more requested files includes a first flat set of data comprised of a plurality of data blocks and a second flat set of data comprised of a second plurality of data blocks, wherein the first flat set of data corresponds to a first archive and the second flat set of data corresponds to a second archive, wherein a first data block of the first flat set of data includes a file offset to a second data block of the second flat set of data;
partially restoring, at a storage system, a file system metadata tree data structure based on the obtained metadata associated with the one or more requested files, wherein the partially restored file system metadata tree data structure includes one or more stub nodes associated with one or more non-requested files; and
providing access to the one or more requested files using the partially restored file system metadata tree data structure.
13. The computer program product of claim 12 , wherein each of the first plurality of data blocks corresponds to a node included in the file system metadata tree data structure.
14. The computer program product of claim 12 , wherein one of the plurality of data blocks includes one or more file offsets to one or more other data blocks.
15. The computer program product of claim 12 , wherein a file offset of the one or more file offsets references a data block of the one or more other data blocks that is included in the first flat set of data.
16. The computer program product of claim 12 , wherein a stub node of the one or more stub nodes references a data block included in a flat set of data stored at the cloud storage.
17. A system, comprising:
a memory; and
a processor coupled to the memory and configured to:
receive a request to access one or more files archived at a cloud storage;
obtain metadata associated with the one or more requested files from a serialized representation of the metadata associated with the one or more requested files stored at the cloud storage, wherein the serialized representation of the metadata associated with the one or more requested files includes a first flat set of data comprised of a plurality of data blocks and a second flat set of data comprised of a second plurality of data blocks, wherein the first flat set of data corresponds to a first archive and the second flat set of data corresponds to a second archive, wherein a first data block of the first flat set of data includes a file offset to a second data block of the second flat set of data;
partially restore, at a storage system, a file system metadata tree data structure based on the obtained metadata associated with the one or more requested files, wherein the partially restored file system metadata tree data structure includes one or more stub nodes associated with one or more non-requested files; and
provide access to the one or more requested files using the partially restored file system metadata tree data structure.
18. The system of claim 17 , wherein each of the first plurality of data blocks corresponds to a node included in the file system metadata tree data structure.