New ext4 features

Revision as of 22:24, 10 January 2007

Multiblock Allocation

• Primary developer: Alex Tomas
• Status: Patches available - ready to push to mainline
• Changes on-disk format: No
• Target Date: ?
• e2fsprogs changes: No
• outstanding issues: none

Delayed Allocation

• Primary developer: Alex Tomas
• Status: Patches available
• Changes on-disk format: No
• Target Date: ?
• e2fsprogs changes: No
• outstanding issues: lack of plan for 1k,2k block size and default data=order mode, and Andrew asked for more comments.

Break 32000 subdirectory limit

• Primary developer: Andreas
• Status: Patches available, need to be resubmitted on ext4
• Changes on-disk format: Yes
• Target Date: ?
• e2fsprogs changes: Needed
• outstanding issues: unknown

nsec timestamps

• Primary developer: Andreas
• Status: Patches available, should not need much rework once issues are resolved
• Change on-disk format: Yes
• Target Date: ?
• e2fsprogs changes: Needed
• outstanding issues: should the feature be available in 128 bit inodes, or only in larger inodes. Performance impact unknown.

inode version on disk

• Primary developer: ?
• Status: Prototype available
• Change on-disk format: Yes
• Target Date: ?
• e2fsprogs changes: Needed
• outstanding issues:

uninitialized groups

• Primary developer: ?
• Status: Prototype available
• Change on-disk format: Yes
• Target Date: ?
• e2fsprogs changes: Needed
• outstanding issues:

journal checksumming

• Primary developer: Andreas
• Status: Prototype available
• Change on-disk format: Yes
• Target Date: ?
• e2fsprogs changes: Needed
• outstanding issues:

persistent preallocation

• Primary developer: Amit Arora, Suparna
• Status: Patches available and reviewed
• Change on-disk format: Yes
• Target Date: Once interface issue is resolved
• e2fsprogs changes: complete
• outstanding issues: Need consensus on what interface should be used (ioctl, fcntl..), should return value be zero or number of block allocated on success

Online Defragmentation

• Primary developer: Takashi Sato
• Status: Patches available
• Change on-disk format:
• Target Date:
• e2fsprogs changes:
• outstanding issues:

Undelete Feature for Ext4

• Primary Developer:
• status: Idea was proposed on the mailing list, still need more thought on the feature.
• Change on-disk format:
• Target Date:
• e2fsprogs changes:
• outstanding issues: Should the kernel be involved with undelete

Large file support

• Primary Developer: Takashi Sato
• status: Increase 2Tb limit on filesize. Takashi has begun working on this.
• Change on-disk format:
• Target Date:
• e2fsprogs Changes:
• outstanding issues: unknown