Deferred copy-on-write of a snapshot

A method for deferring copy-on-write, comprising:

• generating a snapshot including a source file;
• referencing in the snapshot, upon modification of at least one data block associated with the source file, an indirect block associated with the source file, wherein the indirect block references at least one data block;
• allocating at least one data block for the source file;
• assigning a value to a first variable associated with the source file, wherein the value indicates incomplete data blocks associated with the source file;
• and
• assigning a value to a second variable associated with the source file, wherein the value indicates a valid portion of the data blocks associated with the source file.

A system for deferring copy-on-write, comprising:

• means for generating a snapshot including a source file;
• means for referencing in the snapshot, upon modification of a first data block associated with the source file, the first data block;
• means for allocating a second data block for the source file;
• means for assigning a value to a first variable associated with the source file, wherein the value indicates the lack of a complete source file data block;
• and
• means for assigning a value to a second variable associated with the source file, wherein the value indicates a valid portion of the second data block.

A system for deferring copy-on-write, comprising:

• means for generating a snapshot including a source file;
• means for referencing in the snapshot, upon modification of at least one data block associated with the source file, an indirect block associated with the source file, wherein the indirect block references at least one data block;
• means for allocating at least one data block for the source file;
• means for assigning a value to a first variable associated with the source file, wherein the value indicates incomplete data blocks associated with the source file;
• and
• means for assigning a value to a second variable associated with the source file, wherein the value indicates a valid portion of the data blocks associated with the source file.

A computer readable medium including computer instructions for deferring copy-on-write, the computer instructions comprising instructions for:

• generating a snapshot including a source file;
• referencing in the snapshot, upon modification of a first data block associated with the source file, the first data block;
• allocating a second data block for the source file;
• assigning a value to a first variable associated with the source file, wherein the value indicates the lack of a complete source file data block;
• and
• assigning a value to a second variable associated with the source file, wherein the value indicates a valid portion of the second data block.

A computer readable medium including computer instructions for deferring copy-on-write, the computer instructions comprising instructions for:

• generating a snapshot including a source file;
• referencing in the snapshot, upon modification of at least one data block associated with the source file, an indirect block associated with the source file, wherein the indirect block references at least one data block;
• allocating at least one data block for the source file;
• assigning a value to a first variable associated with the source file, wherein the value indicates incomplete data blocks associated with the source file;
• and
• assigning a value to a second variable associated with the source file, wherein the value indicates a valid portion of the data blocks associated with the source file.

A system for deferring copy-on-write, comprising:

• a snapshot including a source file;
• a reference to a first data block associated with the source file, the reference within the snapshot, wherein the reference is generated upon modification of the first data block;
• a second data block for the source file;
• a first variable associated with the source file, wherein a value of the first variable indicates the lack of a complete source file data block;
• and
• a second variable associated with the source file, wherein a value of the second variable indicates a valid portion of the second data block.

A system for deferring copy-on-write, comprising:

• a snapshot including a source file;
• a reference to an indirect block associated with the source file, the reference in the snapshot, wherein the indirect block references at least one data block associated with the source file and wherein the reference is generated upon modification of at least one data block;
• at least one data block for the source file;
• a first variable associated with the source file, wherein a value of the first variable indicates incomplete data blocks associated with the source file;
• and
• a second variable associated with the source file, wherein a value of the second variable indicates a valid portion of the data blocks associated with the source file.

A method for deferring copy-on-write, comprising:

• generating a snapshot including a source file;
• referencing in the snapshot, upon modification of at least one of a first plurality of data blocks associated with the source file, the at least one data block being modified;
• allocating a data block for the source file;
• assigning a value to a first variable associated with the source file, wherein the value indicates incomplete data blocks associated with the source file;
• and
• assigning a value to each of a plurality of variables, wherein each of the plurality of variables is associated with one of the plurality of data blocks associated with the source file and wherein the value of each of the plurality of variables indicates a valid portion of the corresponding data block.

A method for deferring copy-on-write, comprising:

• generating a snapshot including a source file;
• referencing in the snapshot, upon modification of a first data block associated with the source file, the first data block;
• allocating a second data block for the source file;
• and
• assigning a value to a variable associated with the source file, wherein the value indicates a valid portion of the second data block.