Data deduplication is a specialized data compression technique for eliminating duplicate copies of repeating data.[1]
This patch set is also related to "Content based storage" in project ideas[2]. PATCH 1 is a hang fix with deduplication on, but it's also useful without dedup in practice use. PATCH 2 and 3 are targetting delayed refs' scalability problems, which are uncovered by the dedup feature. PATCH 4 is a speed-up improvement, which is about dedup and quota. PATCH 5-8 is the preparation for dedup implementation. PATCH 9 shows how we implement dedup feature. PATCH 10 fixes a backref walking bug with dedup. PATCH 11 fixes a free space bug of dedup extents on error handling. PATCH 12 fixes a race bug on dedup writes. PATCH 13 adds the ioctl to control dedup feature. And there is also a btrfs-progs patch(PATCH 14) which involves all details of how to control dedup feature. I've tested this with xfstests by adding a inline dedup 'enable & on' in xfstests' mount and scratch_mount. TODO: * a bit-to-bit comparison callback. All comments are welcome! [1]: http://en.wikipedia.org/wiki/Data_deduplication [2]: https://btrfs.wiki.kernel.org/index.php/Project_ideas#Content_based_storage v7: - rebase onto the lastest btrfs - break a big patch into smaller ones to make reviewers happy. - kill mount options of dedup and use ioctl method instead. - fix two crash due to the special dedup ref For former patch sets: v6: http://thread.gmane.org/gmane.comp.file-systems.btrfs/27512 v5: http://thread.gmane.org/gmane.comp.file-systems.btrfs/27257 v4: http://thread.gmane.org/gmane.comp.file-systems.btrfs/25751 v3: http://comments.gmane.org/gmane.comp.file-systems.btrfs/25433 v2: http://comments.gmane.org/gmane.comp.file-systems.btrfs/24959 Liu Bo (13): Btrfs: skip merge part for delayed data refs Btrfs: improve the delayed refs process in rm case Btrfs: introduce a head ref rbtree Btrfs: disable qgroups accounting when quata_enable is 0 Btrfs: introduce dedup tree and relatives Btrfs: introduce dedup tree operations Btrfs: introduce dedup state Btrfs: make ordered extent aware of dedup Btrfs: online(inband) data dedup Btrfs: skip dedup reference during backref walking Btrfs: don't return space for dedup extent Btrfs: fix a crash of dedup ref Btrfs: add ioctl of dedup control fs/btrfs/backref.c | 9 + fs/btrfs/ctree.c | 2 +- fs/btrfs/ctree.h | 85 ++++++ fs/btrfs/delayed-ref.c | 159 +++++++---- fs/btrfs/delayed-ref.h | 8 + fs/btrfs/disk-io.c | 45 +++ fs/btrfs/extent-tree.c | 190 +++++++++++-- fs/btrfs/extent_io.c | 22 ++- fs/btrfs/extent_io.h | 15 + fs/btrfs/file-item.c | 230 +++++++++++++++ fs/btrfs/inode.c | 641 +++++++++++++++++++++++++++++++++++++----- fs/btrfs/ioctl.c | 167 +++++++++++ fs/btrfs/ordered-data.c | 38 ++- fs/btrfs/ordered-data.h | 13 +- fs/btrfs/qgroup.c | 3 + fs/btrfs/relocation.c | 3 + fs/btrfs/transaction.c | 4 +- include/trace/events/btrfs.h | 3 +- include/uapi/linux/btrfs.h | 11 + 19 files changed, 1478 insertions(+), 170 deletions(-) -- 1.7.7 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
