File removal with no available disk blocks in redirect-on-write file systems
Embodiments include a method for removing a file within a redirect-on-write file system. In some embodiments, a file removal operation is detected in a file management unit, which resides in a memory unit. It is then determined that the number of free data blocks in the persistent storage is below a minimum threshold. The file removal operation is written to a log used for storing system operations. A file management unit is notified of the successful write of the file removal operation to the log used for storing system operations. The data blocks are moved from the file selected for removal to a list of free data blocks. The indirect blocks from the file selected for removal are moved to a data block removal list.
1. A computer program product for removing a file within a redirect-on-write file system, the computer program product comprising:
a computer readable storage medium having computer usable program code embodied therewith, the computer readable program code configured to,
detect, in a file management unit residing in a memory unit, a file removal operation, wherein a portion of the file is part of a consistency snapshot residing in a main memory, and wherein a portion of the file resides in persistent storage;
detect, in the file management unit, a number of free data block in the persistent storage is below a minimum threshold;
detect, in the file management unit, the file removal operation was successfully written in a log for storing system operations;
move a plurality of data blocks from the file selected for removal to a list of free data blocks, wherein the list of free data blocks identifies available data blocks in the persistent storage;
move a plurality of indirect blocks from the file selected for removal to a data block removal list, wherein the data block removal list identifies data blocks in persistent storage that will be available after the consistency snapshot is written to the persistent storage; and
utilize, in the memory unit, a plurality of indirect blocks, wherein said indirect blocks contain a plurality of data for the file and the indirect blocks are indirectly connected to a file structure.
2. The computer program product of claim 1 , wherein the computer readable program code is further configured to:
detect, in the file management unit residing in the memory unit, a directory removal operation;
move a plurality of data blocks within a directory to the data block removal list; and
move a plurality of indirect blocks within said directory to the data removal list.
3. The computer program product of claim 1 , wherein the computer readable program code is further configured to:
detect, in the file management unit, the file removal operation was not successfully written in the log for storing system operations; and
removal of the file referenced in the file removal operation does not occur.
4. The computer program product of claim 1 , wherein the computer readable program code is further configured to:
detect, in the file management unit, the number of free data blocks in the persistent storage is not below a minimum threshold;
move the plurality of data blocks within the file to a data block removal list; and
move the plurality of indirect blocks within the file to the data block removal list.
5. The computer program product of claim 1 , wherein the computer readable program code is further configured to:
utilize, in the memory unit, a plurality of data blocks, wherein said data blocks contain a plurality of data for said file and the data blocks are directly connected to a file structure.
6. The computer program product of claim 1 , wherein the computer readable program code is further configured to:
utilize, in the memory unit, a plurality of free data blocks, wherein said free data blocks are available to store a plurality of data for the redirect on write file system.