)]}'
{
  "log": [
    {
      "commit": "3fd0a5585eb98e074fb9934549c8d85c49756c0d",
      "tree": "3e7ff9bd9678a5eea62818a2f4a50e19dda91a81",
      "parents": [
        "efa56464562991b8c24f965199888806bd8c4b38"
      ],
      "author": {
        "name": "Yan, Zheng",
        "email": "zheng.yan@oracle.com",
        "time": "Sun May 16 10:49:59 2010 -0400"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Tue May 25 10:34:54 2010 -0400"
      },
      "message": "Btrfs: Metadata ENOSPC handling for balance\n\nThis patch adds metadata ENOSPC handling for the balance code.\nIt is consisted by following major changes:\n\n1. Avoid COW tree leave in the phrase of merging tree.\n\n2. Handle interaction with snapshot creation.\n\n3. make the backref cache can live across transactions.\n\nSigned-off-by: Yan Zheng \u003czheng.yan@oracle.com\u003e\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "efa56464562991b8c24f965199888806bd8c4b38",
      "tree": "e7c7e69e2931674ddf4f14ac08dfdf43b45de0f4",
      "parents": [
        "4a500fd178c89b96fa166a2d9e7855df33429841"
      ],
      "author": {
        "name": "Yan, Zheng",
        "email": "zheng.yan@oracle.com",
        "time": "Sun May 16 10:49:59 2010 -0400"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Tue May 25 10:34:53 2010 -0400"
      },
      "message": "Btrfs: Pre-allocate space for data relocation\n\nPre-allocate space for data relocation. This can detect ENOPSC\ncondition caused by fragmentation of free space.\n\nSigned-off-by: Yan Zheng \u003czheng.yan@oracle.com\u003e\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "a22285a6a32390195235171b89d157ed1a1fe932",
      "tree": "3fabc88a029e1af4f2fdcc708e7b62ef3cf3703a",
      "parents": [
        "f0486c68e4bd9a06a5904d3eeb3a0d73a83befb8"
      ],
      "author": {
        "name": "Yan, Zheng",
        "email": "zheng.yan@oracle.com",
        "time": "Sun May 16 10:48:46 2010 -0400"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Tue May 25 10:34:50 2010 -0400"
      },
      "message": "Btrfs: Integrate metadata reservation with start_transaction\n\nBesides simplify the code, this change makes sure all metadata\nreservation for normal metadata operations are released after\ncommitting transaction.\n\nChanges since V1:\n\nAdd code that check if unlink and rmdir will free space.\n\nAdd ENOSPC handling for clone ioctl.\n\nSigned-off-by: Yan Zheng \u003czheng.yan@oracle.com\u003e\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "f0486c68e4bd9a06a5904d3eeb3a0d73a83befb8",
      "tree": "509428ef400ef45e875a3c448b63b86cbea36aea",
      "parents": [
        "2ead6ae770d9f9dec9f4286bf0fd9001b4388c4b"
      ],
      "author": {
        "name": "Yan, Zheng",
        "email": "zheng.yan@oracle.com",
        "time": "Sun May 16 10:46:25 2010 -0400"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Tue May 25 10:34:50 2010 -0400"
      },
      "message": "Btrfs: Introduce contexts for metadata reservation\n\nIntroducing metadata reseravtion contexts has two major advantages.\nFirst, it makes metadata reseravtion more traceable. Second, it can\nreclaim freed space and re-add them to the itself after transaction\ncommitted.\n\nBesides add btrfs_block_rsv structure and related helper functions,\nThis patch contains following changes:\n\nMove code that decides if freed tree block should be pinned into\nbtrfs_free_tree_block().\n\nMake space accounting more accurate, mainly for handling read only\nblock groups.\n\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "5a0e3ad6af8660be21ca98a971cd00f331318c05",
      "tree": "5bfb7be11a03176a87296a43ac6647975c00a1d1",
      "parents": [
        "ed391f4ebf8f701d3566423ce8f17e614cde9806"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Wed Mar 24 17:04:11 2010 +0900"
      },
      "committer": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Tue Mar 30 22:02:32 2010 +0900"
      },
      "message": "include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h\n\npercpu.h is included by sched.h and module.h and thus ends up being\nincluded when building most .c files.  percpu.h includes slab.h which\nin turn includes gfp.h making everything defined by the two files\nuniversally available and complicating inclusion dependencies.\n\npercpu.h -\u003e slab.h dependency is about to be removed.  Prepare for\nthis change by updating users of gfp and slab facilities include those\nheaders directly instead of assuming availability.  As this conversion\nneeds to touch large number of source files, the following script is\nused as the basis of conversion.\n\n  http://userweb.kernel.org/~tj/misc/slabh-sweep.py\n\nThe script does the followings.\n\n* Scan files for gfp and slab usages and update includes such that\n  only the necessary includes are there.  ie. if only gfp is used,\n  gfp.h, if slab is used, slab.h.\n\n* When the script inserts a new include, it looks at the include\n  blocks and try to put the new include such that its order conforms\n  to its surrounding.  It\u0027s put in the include block which contains\n  core kernel includes, in the same order that the rest are ordered -\n  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there\n  doesn\u0027t seem to be any matching order.\n\n* If the script can\u0027t find a place to put a new include (mostly\n  because the file doesn\u0027t have fitting include block), it prints out\n  an error message indicating which .h file needs to be added to the\n  file.\n\nThe conversion was done in the following steps.\n\n1. The initial automatic conversion of all .c files updated slightly\n   over 4000 files, deleting around 700 includes and adding ~480 gfp.h\n   and ~3000 slab.h inclusions.  The script emitted errors for ~400\n   files.\n\n2. Each error was manually checked.  Some didn\u0027t need the inclusion,\n   some needed manual addition while adding it to implementation .h or\n   embedding .c file was more appropriate for others.  This step added\n   inclusions to around 150 files.\n\n3. The script was run again and the output was compared to the edits\n   from #2 to make sure no file was left behind.\n\n4. Several build tests were done and a couple of problems were fixed.\n   e.g. lib/decompress_*.c used malloc/free() wrappers around slab\n   APIs requiring slab.h to be added manually.\n\n5. The script was run on all .h files but without automatically\n   editing them as sprinkling gfp.h and slab.h inclusions around .h\n   files could easily lead to inclusion dependency hell.  Most gfp.h\n   inclusion directives were ignored as stuff from gfp.h was usually\n   wildly available and often used in preprocessor macros.  Each\n   slab.h inclusion directive was examined and added manually as\n   necessary.\n\n6. percpu.h was updated not to include slab.h.\n\n7. Build test were done on the following configurations and failures\n   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my\n   distributed build env didn\u0027t work with gcov compiles) and a few\n   more options had to be turned off depending on archs to make things\n   build (like ipr on powerpc/64 which failed due to missing writeq).\n\n   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.\n   * powerpc and powerpc64 SMP allmodconfig\n   * sparc and sparc64 SMP allmodconfig\n   * ia64 SMP allmodconfig\n   * s390 SMP allmodconfig\n   * alpha SMP allmodconfig\n   * um on x86_64 SMP allmodconfig\n\n8. percpu.h modifications were reverted so that it could be applied as\n   a separate patch and serve as bisection point.\n\nGiven the fact that I had only a couple of failures from tests on step\n6, I\u0027m fairly confident about the coverage of this conversion patch.\nIf there is a breakage, it\u0027s likely to be something in one of the arch\nheaders which should be easily discoverable easily on most builds of\nthe specific arch.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nGuess-its-ok-by: Christoph Lameter \u003ccl@linux-foundation.org\u003e\nCc: Ingo Molnar \u003cmingo@redhat.com\u003e\nCc: Lee Schermerhorn \u003cLee.Schermerhorn@hp.com\u003e\n"
    },
    {
      "commit": "2ac55d41b5d6bf49e76bc85db5431240617e2f8f",
      "tree": "ee8e2a716ef0b50388ef5e4a86387ec0499bca89",
      "parents": [
        "5a1a3df1f6c86926cfe8657e6f9b4b4c2f467d60"
      ],
      "author": {
        "name": "Josef Bacik",
        "email": "josef@redhat.com",
        "time": "Wed Feb 03 19:33:23 2010 +0000"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Mon Mar 15 11:00:13 2010 -0400"
      },
      "message": "Btrfs: cache the extent state everywhere we possibly can V2\n\nThis patch just goes through and fixes everybody that does\n\nlock_extent()\nblah\nunlock_extent()\n\nto use\n\nlock_extent_bits()\nblah\nunlock_extent_cached()\n\nand pass around a extent_state so we only have to do the searches once per\nfunction.  This gives me about a 3 mb/s boots on my random write test.  I have\nnot converted some things, like the relocation and ioctl\u0027s, since they aren\u0027t\nheavily used and the relocation stuff is in the middle of being re-written.  I\nalso changed the clear_extent_bit() to only unset the cached state if we are\nclearing EXTENT_LOCKED and related stuff, so we can do things like this\n\nlock_extent_bits()\nclear delalloc bits\nunlock_extent_cached()\n\nwithout losing our cached state.  I tested this thoroughly and turned on\nLEAK_DEBUG to make sure we weren\u0027t leaking extent states, everything worked out\nfine.\n\nSigned-off-by: Josef Bacik \u003cjosef@redhat.com\u003e\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "73f73415caddbc01d9f10c03e0a677d5b3d11569",
      "tree": "249ef103a73e8d99efe409b7988b694537b3d6ad",
      "parents": [
        "12534832cb7b0abc7369298246e8b7af03b863ca"
      ],
      "author": {
        "name": "Josef Bacik",
        "email": "josef@redhat.com",
        "time": "Fri Dec 04 17:38:27 2009 +0000"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Mon Mar 15 10:58:13 2010 -0400"
      },
      "message": "Btrfs: change how we mount subvolumes\n\nThis work is in preperation for being able to set a different root as the\ndefault mounting root.\n\nThere is currently a problem with how we mount subvolumes.  We cannot currently\nmount a subvolume of a subvolume, you can only mount subvolumes/snapshots of the\ndefault subvolume.  So say you take a snapshot of the default subvolume and call\nit snap1, and then take a snapshot of snap1 and call it snap2, so now you have\n\n/\n/snap1\n/snap1/snap2\n\nas your available volumes.  Currently you can only mount / and /snap1,\nyou cannot mount /snap1/snap2.  To fix this problem instead of passing\nsubvolid\u003d\u003cname\u003e you must pass in subvolid\u003d\u003ctreeid\u003e, where \u003ctreeid\u003e is\nthe tree id that gets spit out via the subvolume listing you get from\nthe subvolume listing patches (btrfs filesystem list).  This allows us\nto mount /, /snap1 and /snap1/snap2 as the root volume.\n\nIn addition to the above, we also now read the default dir item in the\ntree root to get the root key that it points to.  For now this just\npoints at what has always been the default subvolme, but later on I plan\nto change it to point at whatever root you want to be the new default\nroot, so you can just set the default mount and not have to mount with\n-o subvolid\u003d\u003ctreeid\u003e.  I tested this out with the above scenario and it\nworked perfectly.  Thanks,\n\nmount -o subvol operates inside the selected subvolid.  For example:\n\nmount -o subvol\u003dsnap1,subvolid\u003d256 /dev/xxx /mnt\n\n/mnt will have the snap1 directory for the subvolume with id\n256.\n\nmount -o subvol\u003dsnap /dev/xxx /mnt\n\n/mnt will be the snap directory of whatever the default subvolume\nis.\n\nSigned-off-by: Josef Bacik \u003cjosef@redhat.com\u003e\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "6bef4d317193d3badbbfa3f3c593758ace84a629",
      "tree": "8aa9fcf3297c69033b9a9a83a27ecccaab0f9d7d",
      "parents": [
        "3f6fae9559225741c91f1320090b285da1413290"
      ],
      "author": {
        "name": "Eric Paris",
        "email": "eparis@redhat.com",
        "time": "Tue Feb 23 19:43:04 2010 +0000"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Mon Mar 08 16:26:50 2010 -0500"
      },
      "message": "Btrfs: use RB_ROOT to intialize rb_trees instead of setting rb_node to NULL\n\nbtrfs inialize rb trees in quite a number of places by settin rb_node \u003d\nNULL;  The problem with this is that 17d9ddc72fb8bba0d4f678 in the\nlinux-next tree adds a new field to that struct which needs to be NULL for\nthe new rbtree library code to work properly.  This patch uses RB_ROOT as\nthe intializer so all of the relevant fields will be NULL\u0027d.  Without the\npatch I get a panic.\n\nSigned-off-by: Eric Paris \u003ceparis@redhat.com\u003e\nAcked-by: Venkatesh Pallipadi \u003cvenkatesh.pallipadi@intel.com\u003e\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "d7ce5843bb28ada6845ab2ae8510ba3f12d33154",
      "tree": "c7468abdcaa1d59d789af027984abfdc1bda5248",
      "parents": [
        "014e4ac4f7d9c981750491fa40ea35efadc9ed49"
      ],
      "author": {
        "name": "Miao Xie",
        "email": "miaox@cn.fujitsu.com",
        "time": "Tue Feb 02 08:46:44 2010 +0000"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Thu Feb 04 11:31:44 2010 -0500"
      },
      "message": "Btrfs: remove BUG_ON() due to mounting bad filesystem\n\nMounting a bad filesystem caused a BUG_ON(). The following is steps to\nreproduce it.\n # mkfs.btrfs /dev/sda2\n # mount /dev/sda2 /mnt\n # mkfs.btrfs /dev/sda1 /dev/sda2\n (the program says that /dev/sda2 was mounted, and then exits. )\n # umount /mnt\n # mount /dev/sda1 /mnt\n\nAt the third step, mkfs.btrfs exited in the way of make filesystem. So the\ninitialization of the filesystem didn\u0027t finish. So the filesystem was bad, and\nit caused BUG_ON() when mounting it. But BUG_ON() should be called by the wrong\ncode, not user\u0027s operation, so I think it is a bug of btrfs.\n\nThis patch fixes it.\n\nSigned-off-by: Miao Xie \u003cmiaox@cn.fujitsu.com\u003e\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "2423fdfb96e3f9ff3baeb6c4c78d74145547891d",
      "tree": "a47f7712849dd9ab5c4a1c3371511e072abcdb29",
      "parents": [
        "a038fab0cb873c75d6675e2bcffce8a3935bdce7"
      ],
      "author": {
        "name": "Jiri Slaby",
        "email": "jslaby@suse.cz",
        "time": "Wed Jan 06 16:57:22 2010 +0000"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Sun Jan 17 20:40:20 2010 -0500"
      },
      "message": "Btrfs, fix memory leaks in error paths\n\nStanse found 2 memory leaks in relocate_block_group and\n__btrfs_map_block. cluster and multi are not freed/assigned on all\npaths. Fix that.\n\nSigned-off-by: Jiri Slaby \u003cjslaby@suse.cz\u003e\nCc: linux-btrfs@vger.kernel.org\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "24bbcf0442ee04660a5a030efdbb6d03f1c275cb",
      "tree": "aa57d77d29cc5150b272cc3f6465f10262fcbaac",
      "parents": [
        "f34f57a3ab4e73304d78c125682f1a53cd3975f2"
      ],
      "author": {
        "name": "Yan, Zheng",
        "email": "zheng.yan@oracle.com",
        "time": "Thu Nov 12 09:36:34 2009 +0000"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Thu Dec 17 12:33:35 2009 -0500"
      },
      "message": "Btrfs: Add delayed iput\n\niput() can trigger new transactions if we are dropping the\nfinal reference, so calling it in btrfs_commit_transaction\nmay end up deadlock. This patch adds delayed iput to avoid\nthe issue.\n\nSigned-off-by: Yan Zheng \u003czheng.yan@oracle.com\u003e\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "8082510e7124cc50d728f1b875639cb4e22312cc",
      "tree": "e9f0a0a4504a87689b4765368b508fff5ae2ddf8",
      "parents": [
        "5a303d5d4b8055d2e5a03e92d04745bfc5881a22"
      ],
      "author": {
        "name": "Yan, Zheng",
        "email": "zheng.yan@oracle.com",
        "time": "Thu Nov 12 09:35:36 2009 +0000"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Thu Dec 17 12:33:34 2009 -0500"
      },
      "message": "Btrfs: Make truncate(2) more ENOSPC friendly\n\ntruncating and deleting regular files are unbound operations,\nso it\u0027s not good to do them in a single transaction. This\npatch makes btrfs_truncate and btrfs_delete_inode start a\nnew transaction after all items in a tree leaf are deleted.\n\nSigned-off-by: Yan Zheng \u003czheng.yan@oracle.com\u003e\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "c71bf099abddf3e0fdc27f251ba76fca1461d49a",
      "tree": "0b682ad2b49aeaf9ac774c40be4b7549c1d079fe",
      "parents": [
        "c216775458a2ee345d9412a2770c2916acfb5d30"
      ],
      "author": {
        "name": "Yan, Zheng",
        "email": "zheng.yan@oracle.com",
        "time": "Thu Nov 12 09:34:40 2009 +0000"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Thu Dec 17 12:33:33 2009 -0500"
      },
      "message": "Btrfs: Avoid orphan inodes cleanup while replaying log\n\nWe do log replay in a single transaction, so it\u0027s not good to do unbound\noperations. This patch cleans up orphan inodes cleanup after replaying\nthe log. It also avoids doing other unbound operations such as truncating\na file during replaying log. These unbound operations are postponed to\nthe orphan inode cleanup stage.\n\nSigned-off-by: Yan Zheng \u003czheng.yan@oracle.com\u003e\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "61d92c328c16419fc96dc50dd16f8b8c695409ec",
      "tree": "e9cd82eb56ff5f38f64d9f35229d15496e5d53de",
      "parents": [
        "fbf190874407f23d2891b53ffdf7d3c6be8d47ff"
      ],
      "author": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Fri Oct 02 19:11:56 2009 -0400"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Mon Oct 05 09:44:45 2009 -0400"
      },
      "message": "Btrfs: fix deadlock on async thread startup\n\nThe btrfs async worker threads are used for a wide variety of things,\nincluding processing bio end_io functions.  This means that when\nthe endio threads aren\u0027t running, the rest of the FS isn\u0027t\nable to do the final processing required to clear PageWriteback.\n\nThe endio threads also try to exit as they become idle and\nstart more as the work piles up.  The problem is that starting more\nthreads means kthreadd may need to allocate ram, and that allocation\nmay wait until the global number of writeback pages on the system is\nbelow a certain limit.\n\nThe result of that throttling is that end IO threads wait on\nkthreadd, who is waiting on IO to end, which will never happen.\n\nThis commit fixes the deadlock by handing off thread startup to a\ndedicated thread.  It also fixes a bug where the on-demand thread\ncreation was creating far too many threads because it didn\u0027t take into\naccount threads being started by other procs.\n\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "0257bb82d21bedff26541bcf12f1461c23f9ed61",
      "tree": "0b79fd9bf377094f6fa6f5f923fe192515672af3",
      "parents": [
        "f679a84034be6f7da123be786bbd8838bf3e9207"
      ],
      "author": {
        "name": "Yan, Zheng",
        "email": "zheng.yan@oracle.com",
        "time": "Thu Sep 24 09:17:31 2009 -0400"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Thu Sep 24 09:17:31 2009 -0400"
      },
      "message": "Btrfs: relocate file extents in clusters\n\nThe extent relocation code copy file extents one by one when\nrelocating data block group. This is inefficient if file\nextents are small. This patch makes the relocation code copy\nfile extents in clusters. So we can can make better use of\nread-ahead.\n\nSigned-off-by: Yan Zheng \u003czheng.yan@oracle.com\u003e\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "76dda93c6ae2c1dc3e6cde34569d6aca26b0c918",
      "tree": "f5ca46ec89d4ae2c762952d5f35e2c6f95ac046a",
      "parents": [
        "4df27c4d5cc1dda54ed7d0a8389347f2df359cf9"
      ],
      "author": {
        "name": "Yan, Zheng",
        "email": "zheng.yan@oracle.com",
        "time": "Mon Sep 21 16:00:26 2009 -0400"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Mon Sep 21 16:00:26 2009 -0400"
      },
      "message": "Btrfs: add snapshot/subvolume destroy ioctl\n\nThis patch adds snapshot/subvolume destroy ioctl.  A subvolume that isn\u0027t being\nused and doesn\u0027t contains links to other subvolumes can be destroyed.\n\nSigned-off-by: Yan Zheng \u003czheng.yan@oracle.com\u003e\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "9655d2982b53fdb38a9e0f2f11315b99b92d66e2",
      "tree": "e1271f2f2a3c2c356e0692b36a2d4742b5d651d8",
      "parents": [
        "d5550c6315fe0647b7ac21a6a736bf4a42620eac"
      ],
      "author": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Wed Sep 02 15:22:30 2009 -0400"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Fri Sep 11 13:31:07 2009 -0400"
      },
      "message": "Btrfs: use a cached state for extent state operations during delalloc\n\nThis changes the btrfs code to find delalloc ranges in the extent state\ntree to use the new state caching code from set/test bit.  It reduces\none of the biggest causes of rbtree searches in the writeback path.\n\ntest_range_bit is also modified to take the cached state as a starting\npoint while searching.\n\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "890871be854b5f5e43e7ba2475f706209906cc24",
      "tree": "9d087adf7a28bb910992d07d93ea2a992e394110",
      "parents": [
        "57fd5a5ff8b48b99e90b22fc143082aba755c6c0"
      ],
      "author": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Wed Sep 02 16:24:52 2009 -0400"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Fri Sep 11 13:31:05 2009 -0400"
      },
      "message": "Btrfs: switch extent_map to a rw lock\n\nThere are two main users of the extent_map tree.  The\nfirst is regular file inodes, where it is evenly spread\nbetween readers and writers.\n\nThe second is the chunk allocation tree, which maps blocks from\nlogical addresses to phyiscal ones, and it is 99.99% reads.\n\nThe mapping tree is a point of lock contention during heavy IO\nworkloads, so this commit switches things to a rw lock.\n\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "ceab36edd3d3ad3ffd01d41d6d1e05ac1ff8357e",
      "tree": "a6d899030878d52ae6d7932e459deece3524c787",
      "parents": [
        "60f2e8f8a07331097a57ec4abcdc680405579377"
      ],
      "author": {
        "name": "Yan Zheng",
        "email": "zheng.yan@oracle.com",
        "time": "Fri Aug 07 13:51:33 2009 -0400"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Fri Aug 07 13:51:33 2009 -0400"
      },
      "message": "Btrfs: fix balancing oops when invalidate_inode_pages2 returns EBUSY\n\ninvalidate_inode_pages2_range may return -EBUSY occasionally\nwhich results Oops. This patch fixes the issue by moving\ninvalidate_inode_pages2_range into a loop and keeping calling\nit until the return value is not -EBUSY.\n\nThe EBUSY return is temporary, and can happen when the btrfs release page\nfunction is unable to release a page because the EXTENT_LOCK\nbit is set.\n\nSigned-off-by: Yan Zheng \u003czheng.yan@oracle.com\u003e\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "33c66f430bfa3a033e70470e4c93f967156b696d",
      "tree": "5af7edc4564aa3f32033b364495828eb32b690a7",
      "parents": [
        "e457afec60fdbd86b963d36f4a8a9285088c6043"
      ],
      "author": {
        "name": "Yan Zheng",
        "email": "zheng.yan@oracle.com",
        "time": "Wed Jul 22 09:59:00 2009 -0400"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Wed Jul 22 09:59:00 2009 -0400"
      },
      "message": "Btrfs: fix locking issue in btrfs_find_next_key\n\nWhen walking up the tree, btrfs_find_next_key assumes the upper level tree\nblock is properly locked. This isn\u0027t always true even path-\u003ekeep_locks is 1.\nThis is because btrfs_find_next_key may advance path-\u003eslots[] several times\ninstead of only once.\n\nWhen \u0027path-\u003eslots[level] \u003e\u003d btrfs_header_nritems(path-\u003enodes[level])\u0027 is found,\nwe can\u0027t guarantee the original value of \u0027path-\u003eslots[level]\u0027 is\n\u0027btrfs_header_nritems(path-\u003enodes[level]) - 1\u0027. If it\u0027s not, the tree block at\n\u0027level + 1\u0027 isn\u0027t locked.\n\nThis patch fixes the issue by explicitly checking the locking state,\nre-searching the tree if it\u0027s not locked.\n\nSigned-off-by: Yan Zheng \u003czheng.yan@oracle.com\u003e\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "2c47e605a91dde6b0514f689645e7ab336c8592a",
      "tree": "d541e61440f06f37d17e2d14cbaa78fc0cd41ff2",
      "parents": [
        "a970b0a16cc416a509d5ae8b1d70978664e6f4fe"
      ],
      "author": {
        "name": "Yan Zheng",
        "email": "zheng.yan@oracle.com",
        "time": "Sat Jun 27 21:07:35 2009 -0400"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Thu Jul 02 13:41:17 2009 -0400"
      },
      "message": "Btrfs: update backrefs while dropping snapshot\n\nThe new backref format has restriction on type of backref item.  If a tree\nblock isn\u0027t referenced by its owner tree, full backrefs must be used for the\npointers in it. When a tree block loses its owner tree\u0027s reference, backrefs\nfor the pointers in it should be updated to full backrefs. Current\nbtrfs_drop_snapshot misses the code that updates backrefs, so it\u0027s unsafe for\ngeneral use.\n\nThis patch adds backrefs update code to btrfs_drop_snapshot.  It isn\u0027t a\nproblem in the restricted form btrfs_drop_snapshot is used today, but for\ngeneral snapshot deletion this update is required.\n\nSigned-off-by: Yan Zheng \u003czheng.yan@oracle.com\u003e\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    },
    {
      "commit": "5d4f98a28c7d334091c1b7744f48a1acdd2a4ae0",
      "tree": "c611d7d824cbcdb777dd2d8e33e2ed1c5df8a9c6",
      "parents": [
        "5c939df56c3ea018b58e5aa76181284c2053d699"
      ],
      "author": {
        "name": "Yan Zheng",
        "email": "zheng.yan@oracle.com",
        "time": "Wed Jun 10 10:45:14 2009 -0400"
      },
      "committer": {
        "name": "Chris Mason",
        "email": "chris.mason@oracle.com",
        "time": "Wed Jun 10 11:29:46 2009 -0400"
      },
      "message": "Btrfs: Mixed back reference  (FORWARD ROLLING FORMAT CHANGE)\n\nThis commit introduces a new kind of back reference for btrfs metadata.\nOnce a filesystem has been mounted with this commit, IT WILL NO LONGER\nBE MOUNTABLE BY OLDER KERNELS.\n\nWhen a tree block in subvolume tree is cow\u0027d, the reference counts of all\nextents it points to are increased by one.  At transaction commit time,\nthe old root of the subvolume is recorded in a \"dead root\" data structure,\nand the btree it points to is later walked, dropping reference counts\nand freeing any blocks where the reference count goes to 0.\n\nThe increments done during cow and decrements done after commit cancel out,\nand the walk is a very expensive way to go about freeing the blocks that\nare no longer referenced by the new btree root.  This commit reduces the\ntransaction overhead by avoiding the need for dead root records.\n\nWhen a non-shared tree block is cow\u0027d, we free the old block at once, and the\nnew block inherits old block\u0027s references. When a tree block with reference\ncount \u003e 1 is cow\u0027d, we increase the reference counts of all extents\nthe new block points to by one, and decrease the old block\u0027s reference count by\none.\n\nThis dead tree avoidance code removes the need to modify the reference\ncounts of lower level extents when a non-shared tree block is cow\u0027d.\nBut we still need to update back ref for all pointers in the block.\nThis is because the location of the block is recorded in the back ref\nitem.\n\nWe can solve this by introducing a new type of back ref. The new\nback ref provides information about pointer\u0027s key, level and in which\ntree the pointer lives. This information allow us to find the pointer\nby searching the tree. The shortcoming of the new back ref is that it\nonly works for pointers in tree blocks referenced by their owner trees.\n\nThis is mostly a problem for snapshots, where resolving one of these\nfuzzy back references would be O(number_of_snapshots) and quite slow.\nThe solution used here is to use the fuzzy back references in the common\ncase where a given tree block is only referenced by one root,\nand use the full back references when multiple roots have a reference\non a given block.\n\nThis commit adds per subvolume red-black tree to keep trace of cached\ninodes. The red-black tree helps the balancing code to find cached\ninodes whose inode numbers within a given range.\n\nThis commit improves the balancing code by introducing several data\nstructures to keep the state of balancing. The most important one\nis the back ref cache. It caches how the upper level tree blocks are\nreferenced. This greatly reduce the overhead of checking back ref.\n\nThe improved balancing code scales significantly better with a large\nnumber of snapshots.\n\nThis is a very large commit and was written in a number of\npieces.  But, they depend heavily on the disk format change and were\nsquashed together to make sure git bisect didn\u0027t end up in a\nbad state wrt space balancing or the format change.\n\nSigned-off-by: Yan Zheng \u003czheng.yan@oracle.com\u003e\nSigned-off-by: Chris Mason \u003cchris.mason@oracle.com\u003e\n"
    }
  ]
}