Versioning in internet file system

Abstract

Techniques are provided for managing versions of files in a file system. According to one technique, new versions of directories are created in response to creation of new versions of files that descend from the directories, where the different versions of a versioned directory are associated with different points in time. Links are maintained between the files in the file system such that the versions of the files that descend from a particular version of a versioned directory reflect the point in time associated with the versioned directory.

1 . A computer-implemented method for managing versions of files in a file system, the method comprising:
 creating new versions of directories in response to creation of new versions of files that descend from the directories, where the different versions of a versioned directory are associated with different points in time; and   maintaining links between the files in the file system such that the versions of the files that descend from a particular version of a versioned directory reflect the point in time associated with the versioned directory.   
     
     
         2 . The method of  claim 1 , further comprising:
 determining a selected point in time that files are to reflect for a particular operation;   selecting a particular version of a directory from a plurality of versions of the directory on the basis that the particular version of the directory is associated with the selected point in time; and   following links from the selected version of the directory to locate one or more files involved in said operation.   
     
     
         3 . The method of  claim 1 , further comprising:
 receiving input indicating movement of a particular file from a first version of a first directory to a first version of a second directory;   wherein the first version of the first directory includes a first set of zero or more files other than said particular file;   wherein the first version of the second directory includes a second set of zero or more files other than said particular file;   wherein maintaining links includes performing the following steps in response to said input:
 creating a second version of said first directory; 
 establishing said first set of zero or more files as members of said second version of said first directory without establishing said particular file as a member of said second version of said first directory; 
 creating a second version of said second directory; and 
 establishing said particular file and said second set of zero or more files as members of said second version of said second directory. 
   
     
     
         4 . The method of  claim 1 , further comprising:
 receiving an update to a first version of a particular file;   wherein the first version of said particular file is stored in a first version of a particular directory;   wherein the first version of the particular directory includes one or more files other than said particular file;   wherein maintaining links includes performing the following steps in response to the update:
 creating a second version of said particular directory; 
 creating a second version of said particular file; 
 establishing said one or more files as members of said second version of said particular directory; and 
 establishing said second version of said particular file as a member of said second version of said particular directory while maintaining said first version of said particular file as a member of said first version of said particular directory. 
   
     
     
         5 . One or more non-transitory computer-readable media carrying instructions which, when executed by one or more processors, cause:
 creating new versions of directories in response to creation of new versions of files that descend from the directories, where the different versions of a versioned directory are associated with different points in time; and   maintaining links between the files in a file system such that the versions of the files that descend from a particular version of a versioned directory reflect the point in time associated with the versioned directory.   
     
     
         6 . The one or more computer-readable media of  claim 5 , wherein instructions, when executed by the one or more processors, further cause:
 determining a selected point in time that files are to reflect for a particular operation;   selecting a particular version of a directory from a plurality of versions of the directory on the basis that the particular version of the directory is associated with the selected point in time; and   following links from the selected version of the directory to locate one or more files involved in said operation.   
     
     
         7 . The one or more computer-readable media of  claim 5 , wherein the instructions, when executed by the one or more processors, further cause:
 receiving input indicating movement of a particular file from a first version of a first directory to a first version of a second directory;   wherein the first version of the first directory includes a first set of zero or more files other than said particular file;   wherein the first version of the second directory includes a second set of zero or more files other than said particular file;   wherein maintaining links includes performing the following steps in response to said input:
 creating a second version of said first directory; 
 establishing said first set of zero or more files as members of said second version of said first directory without establishing said particular file as a member of said second version of said first directory; 
 creating a second version of said second directory; and 
 establishing said particular file and said second set of zero or more files as members of said second version of said second directory. 
   
     
     
         8 . The one or more computer-readable media of  claim 5 , wherein the instructions, when executed by the one or more processors, further cause:
 receiving an update to a first version of a particular file;   wherein the first version of said particular file is stored in a first version of a particular directory;   wherein the first version of the particular directory includes one or more files other than said particular file;   wherein maintaining links includes performing the following steps in response to the update:
 creating a second version of said particular directory; 
 creating a second version of said particular file; 
 establishing said one or more files as members of said second version of said particular directory; and 
 establishing said second version of said particular file as a member of said second version of said particular directory while maintaining said first version of said particular file as a member of said first version of said particular directory.