Hello, This the 9th attempt for in-band data dedupe. 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], it introduces inband data deduplication for btrfs and dedup/dedupe is for short. * PATCH 1 is a speed-up improvement, which is about dedup and quota. * PATCH 2-5 is the preparation work for dedup implementation. * PATCH 6 shows how we implement dedup feature. * PATCH 7 fixes a backref walking bug with dedup. * PATCH 8 fixes a free space bug of dedup extents on error handling. * PATCH 9 adds the ioctl to control dedup feature. * PATCH 10 targets delayed refs' scalability problem of deleting refs, which is uncovered by the dedup feature. * PATCH 11-16 fixes bugs of dedupe including race bug, deadlock, abnormal transaction abortion and crash. * btrfs-progs patch(PATCH 17) which offers all details about how to control the dedup feature on progs side. I've tested this with xfstests by adding a inline dedup 'enable & on' in xfstests' mount and scratch_mount. ***NOTE*** Known bugs: * Mounting with options "flushoncommit" and enabling dedupe feature will end up with _deadlock_. 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 v9: - fix a deadlock and a crash reported by users. - fix the metadata ENOSPC problem with dedup again. v8: - fix the race crash of dedup ref again. - fix the metadata ENOSPC problem with dedup. 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 (16): 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: add ioctl of dedup control Btrfs: improve the delayed refs process in rm case Btrfs: fix a crash of dedup ref Btrfs: fix deadlock of dedup work Btrfs: fix transactin abortion in __btrfs_free_extent Btrfs: fix wrong pinned bytes in __btrfs_free_extent Btrfs: use total_bytes instead of bytes_used for global_rsv Btrfs: fix dedup enospc problem fs/btrfs/backref.c | 9 + fs/btrfs/ctree.c | 2 +- fs/btrfs/ctree.h | 86 ++++++ fs/btrfs/delayed-ref.c | 26 +- fs/btrfs/delayed-ref.h | 3 + fs/btrfs/disk-io.c | 37 +++ fs/btrfs/extent-tree.c | 235 +++++++++++++--- fs/btrfs/extent_io.c | 22 +- fs/btrfs/extent_io.h | 16 ++ fs/btrfs/file-item.c | 244 +++++++++++++++++ fs/btrfs/inode.c | 635 ++++++++++++++++++++++++++++++++++++++----- fs/btrfs/ioctl.c | 167 ++++++++++++ fs/btrfs/ordered-data.c | 44 ++- fs/btrfs/ordered-data.h | 13 +- fs/btrfs/qgroup.c | 3 + fs/btrfs/relocation.c | 3 + fs/btrfs/transaction.c | 41 +++ fs/btrfs/transaction.h | 1 + include/trace/events/btrfs.h | 3 +- include/uapi/linux/btrfs.h | 11 + 20 files changed, 1470 insertions(+), 131 deletions(-) -- 1.8.2.1 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html