)]}'
{
  "log": [
    {
      "commit": "2e966ed22c3c56227f8a7322d7b008945352e6ab",
      "tree": "101bb798295de6a299d7f6febd437887134f5e43",
      "parents": [
        "93dbfad7ac647d4f00354893fe93e8a55be114d5"
      ],
      "author": {
        "name": "Jim Owens",
        "email": "jowens@hp.com",
        "time": "Thu Apr 02 17:02:55 2009 -0400"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Thu Apr 02 17:02:55 2009 -0400"
      },
      "message": "Btrfs: remove unused ftrace include\n\nSigned-off-by: jim owens \u003cjowens@hp.com\u003e\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n\n"
    },
    {
      "commit": "1a81af4d1d9c60d4313309f937a1fc5567205a87",
      "tree": "535b65b3948d34f0948613afc6ebdfe693683f33",
      "parents": [
        "af4176b49c5ee15a9c9b10720c92456b28e7aac7"
      ],
      "author": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Wed Mar 25 09:55:11 2009 -0400"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Wed Mar 25 09:55:11 2009 -0400"
      },
      "message": "Btrfs: make sure btrfs_update_delayed_ref doesn\u0027t increase ref_mod\n\nbtrfs_update_delayed_ref is optimized to add and remove different\nreferences in one pass through the delayed ref tree.  It is a zero\nsum on the total number of refs on a given extent.\n\nBut, the code was recording an extra ref in the head node.  This\nnever made it down to the disk but was used when deciding if it was\nsafe to free the extent while dropping snapshots.\n\nThe fix used here is to make sure the ref_mod count is unchanged\non the head ref when btrfs_update_delayed_ref is called.\n\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "c3e69d58e86c3917ae4e9e31b4acf490a7cafe60",
      "tree": "bd4f1e62446a208bdae26f0c36d67e3afbc1cd1d",
      "parents": [
        "1887be66dcc3140a81d1299958a41fc0eedfa64f"
      ],
      "author": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Fri Mar 13 10:17:05 2009 -0400"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Tue Mar 24 16:14:26 2009 -0400"
      },
      "message": "Btrfs: process the delayed reference queue in clusters\n\nThe delayed reference queue maintains pending operations that need to\nbe done to the extent allocation tree.  These are processed by\nfinding records in the tree that are not currently being processed one at\na time.\n\nThis is slow because it uses lots of time searching through the rbtree\nand because it creates lock contention on the extent allocation tree\nwhen lots of different procs are running delayed refs at the same time.\n\nThis commit changes things to grab a cluster of refs for processing,\nusing a cursor into the rbtree as the starting point of the next search.\nThis way we walk smoothly through the rbtree.\n\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "1887be66dcc3140a81d1299958a41fc0eedfa64f",
      "tree": "3f0666948a83c48c77e0c37dca1c71a6aff9eb1d",
      "parents": [
        "44871b1b24b593996db43495cf4484cc580bdc10"
      ],
      "author": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Fri Mar 13 10:11:24 2009 -0400"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Tue Mar 24 16:14:26 2009 -0400"
      },
      "message": "Btrfs: try to cleanup delayed refs while freeing extents\n\nWhen extents are freed, it is likely that we\u0027ve removed the last\ndelayed reference update for the extent.  This checks the delayed\nref tree when things are freed, and if no ref updates area left it\nimmediately processes the delayed ref.\n\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "56bec294dea971335d4466b30f2d959f28f6e36d",
      "tree": "fc0b5bbf4bb6ab35582a4c7f58f5ac88f71c38bf",
      "parents": [
        "9fa8cfe706f9c20067c042a064999d5825a35330"
      ],
      "author": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Fri Mar 13 10:10:06 2009 -0400"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Tue Mar 24 16:14:25 2009 -0400"
      },
      "message": "Btrfs: do extent allocation and reference count updates in the background\n\nThe extent allocation tree maintains a reference count and full\nback reference information for every extent allocated in the\nfilesystem.  For subvolume and snapshot trees, every time\na block goes through COW, the new copy of the block adds a reference\non every block it points to.\n\nIf a btree node points to 150 leaves, then the COW code needs to go\nand add backrefs on 150 different extents, which might be spread all\nover the extent allocation tree.\n\nThese updates currently happen during btrfs_cow_block, and most COWs\nhappen during btrfs_search_slot.  btrfs_search_slot has locks held\non both the parent and the node we are COWing, and so we really want\nto avoid IO during the COW if we can.\n\nThis commit adds an rbtree of pending reference count updates and extent\nallocations.  The tree is ordered by byte number of the extent and byte number\nof the parent for the back reference.  The tree allows us to:\n\n1) Modify back references in something close to disk order, reducing seeks\n2) Significantly reduce the number of modifications made as block pointers\nare balanced around\n3) Do all of the extent insertion and back reference modifications outside\nof the performance critical btrfs_search_slot code.\n\n#3 has the added benefit of greatly reducing the btrfs stack footprint.\nThe extent allocation tree modifications are done without the deep\n(and somewhat recursive) call chains used in the past.\n\nThese delayed back reference updates must be done before the transaction\ncommits, and so the rbtree is tied to the transaction.  Throttling is\nimplemented to help keep the queue of backrefs at a reasonable size.\n\nSince there was a similar mechanism in place for the extent tree\nextents, that is removed and replaced by the delayed reference tree.\n\nYan Zheng \u003cyan.zheng@oracle.com\u003e helped review and fixup this code.\n\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    }
  ]
}