Methods and apparatus for changing versions of a filesystem

Abstract

A filesystem can be converted to a different version by creating a new data structure according to a new format of the different version and transforming the data from the filesystem to the new data structure. Transforming the data can include changing the format of the data in the filesystem to be compatible with the new data structure format. The data may be incorporated into the new data structure by copying the data, or creating indirect reference mechanisms to point to the original data.

1 . A method for converting a filesystem to a different version, comprising:
 generating a new logical data structure in free space of an original logical data structure of the filesystem to convert the filesystem to the different version, the original logical data structure formatted according to a first format, and the new logical data structure formatted according to a second format;   incorporating data from the original logical data structure of the first format to the new logical data structure of the second format.   
     
     
         2 . A method according to  claim 1 , wherein the new logical data structure comprises a volume. 
     
     
         3 . A method according to  claim 1 , wherein generating the new logical data structure to convert the filesystem to the different version comprises performing a filesystem upgrade from a former version to an updated version. 
     
     
         4 . A method according to  claim 1 , wherein generating the new logical data structure to convert the filesystem to the different version comprises performing a filesystem revert to revert from an updated version to a former version. 
     
     
         5 . A method according to  claim 1 , wherein generating the new logical data structure to convert the filesystem to the different version comprises performing data replication of a filesystem having a data structure that is incompatible with a storage server. 
     
     
         6 . A method according to  claim 1 , wherein the second format has data block sizes that are a scaled ratio of the data block sizes of the first format. 
     
     
         7 . A method according to  claim 6 , further comprising:
 determining that a data block of the original logical data structure is unused; and   deleting the unused data block from the original logical data structure.   
     
     
         8 . A method according to  claim 7 , further comprising:
 incorporating the data block deleted from the original logical data structure into the new logical data structure as available storage after deleting the data block from the original logical data structure.   
     
     
         9 . A method according to  claim 6 , wherein incorporating the data from the original logical data structure to the new logical data structure further comprises:
 generating a pointer in the new logical data structure to point to the storage space of the data of the original logical data structure; and   deleting reference to the data in the original logical data structure.   
     
     
         10 . A method according to  claim 1 , wherein the second format has data block sizes that are not a scaled ratio of the data block sizes of the first format, wherein incorporating the data from the original logical data structure to the new logical data structure further comprises:
 copying data blocks from the original logical data structure into data blocks sized to be a scaled ratio of the data block sizes of the second format.   
     
     
         11 . A method according to  claim 1 , wherein incorporating the data from the original logical data structure to the new logical data structure further comprises:
 reading the data of the original logical data structure;   converting the data into the second format; and   storing the data in storage space managed by the new logical data structure.   
     
     
         12 . An article of manufacture comprising a machine-accessible medium having content to provide instructions, which when executed result in a machine performing operations including:
 creating a new filesystem in free space of an original filesystem, the new filesystem having a format different from the original filesystem to manage data access to the free space in accordance with the format of the new filesystem;   providing an iterative conversion procedure to access data of the original filesystem, convert the data to the format of the new filesystem, and incorporate the data from the original filesystem into the free space managed by the new filesystem; and   deleting the converted data from the original filesystem.   
     
     
         13 . An article of manufacture according to  claim 12 , wherein creating the new filesystem comprises creating a sparse volume in the free space of the original filesystem, and wherein incorporating the data from the original filesystem into the free space comprises generating absent block to point to data of the original filesystem. 
     
     
         14 . An article of manufacture according to  claim 12 , wherein converting the data to the format of the new filesystem comprises copying data from a block size incompatible with the format of the new filesystem to a block size compatible with the format of the new filesystem. 
     
     
         15 . An article of manufacture according to  claim 12 , wherein deleting the converted data further comprises removing the data space of the deleted data from the original filesystem and making the data space available to the new filesystem. 
     
     
         16 . A storage server comprising:
 an original filesystem having a virtual data structure according to an original format, and having free space; and   a transformer module to generate a new filesystem having a new virtual data structure according to a new format in the free space, and to transform the data from the virtual data structure of the original filesystem into the new virtual data structure according to the new format.   
     
     
         17 . A storage server according to  claim 16 , wherein the transformer module comprises a new kernel to execute the new filesystem according to the new format, and a translation module to convert the data from the original filesystem to the new filesystem. 
     
     
         18 . A storage server according to  claim 17 , the translation module to further iteratively step through the virtual data structure of the original filesystem and convert the virtual data structure block-by-block into the new format to be stored in the new virtual data structure. 
     
     
         19 . A storage server according to  claim 16 , wherein to transform the data into the new virtual data structure according to the new format comprises to create a pointer to the data of the virtual data structure, the pointer to be stored in the new virtual data structure. 
     
     
         20 . A storage server according to  claim 16 , wherein to transform the data into the new virtual data structure according to the new format comprises to copy data from the virtual data structure of the original filesystem of one block size into data blocks of a different size.