)]}'
{
  "log": [
    {
      "commit": "4e13e66bee2d792c1aae21797f16c181024834eb",
      "tree": "1fa51dade28bc025d9bda0e09dec1f202281a498",
      "parents": [
        "464ece88630d0fb715ca942eabb1da825046a534"
      ],
      "author": {
        "name": "Ryusuke Konishi",
        "email": "konishi.ryusuke@lab.ntt.co.jp",
        "time": "Sun Jul 18 10:42:25 2010 +0900"
      },
      "committer": {
        "name": "Ryusuke Konishi",
        "email": "konishi.ryusuke@lab.ntt.co.jp",
        "time": "Fri Jul 23 10:02:15 2010 +0900"
      },
      "message": "nilfs2: introduce check flag to btree node buffer\n\nnilfs_btree_get_block() now may return untested buffer due to\nread-ahead.  This adds a new flag for buffer heads so that the btree\ncode can check whether the buffer is already verified or not.\n\nSigned-off-by: Ryusuke Konishi \u003ckonishi.ryusuke@lab.ntt.co.jp\u003e\n"
    },
    {
      "commit": "0bd49f9446130a6a3914eb07b54db489e3222b34",
      "tree": "5122a227c9cb1cfe92a74c53baf1bb7ca7053435",
      "parents": [
        "a60be987d45dd510aeb54389526f9957cfab106c"
      ],
      "author": {
        "name": "Ryusuke Konishi",
        "email": "konishi.ryusuke@lab.ntt.co.jp",
        "time": "Mon Apr 06 19:01:27 2009 -0700"
      },
      "committer": {
        "name": "Linus Torvalds",
        "email": "torvalds@linux-foundation.org",
        "time": "Tue Apr 07 08:31:13 2009 -0700"
      },
      "message": "nilfs2: buffer and page operations\n\nThis adds common routines for buffer/page operations used in B-tree\nnode caches, meta data files, or segment constructor (log writer).\n\nNILFS uses copy functions for buffers and pages due to the following\nreasons:\n\n 1) Relocation required for COW\n    Since NILFS changes address of on-disk blocks, moving buffers\n    in page cache is needed for the buffers which are not addressed\n    by a file offset.  If buffer size is smaller than page size,\n    this involves partial copy of pages.\n\n 2) Freezing mmapped pages\n    NILFS calculates checksums for each log to ensure its validity.\n    If page data changes after the checksum calculation, this validity\n    check will not work correctly.  To avoid this failure for mmaped\n    pages, NILFS freezes their data by copying.\n\n 3) Copy-on-write for DAT pages\n    NILFS makes clones of DAT page caches in a copy-on-write manner\n    during GC processes, and this ensures atomicity and consistency\n    of the DAT in the transient state.\n\nIn addition, NILFS uses two obsolete functions, nilfs_mark_buffer_dirty()\nand nilfs_clear_page_dirty() respectively.\n\n* nilfs_mark_buffer_dirty() was required to avoid NULL pointer\n  dereference faults:\n\n  Since the page cache of B-tree node pages or data page cache of pseudo\n  inodes does not have a valid mapping-\u003ehost, calling mark_buffer_dirty()\n  for their buffers causes the fault; it calls __mark_inode_dirty(NULL)\n  through __set_page_dirty().\n\n* nilfs_clear_page_dirty() was needed in the two cases:\n\n 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears\n    page dirty flags when it copies back pages from the cloned cache\n    (gcdat-\u003e{i_mapping,i_btnode_cache}) to its original cache\n    (dat-\u003e{i_mapping,i_btnode_cache}).\n\n 2) Some B-tree operations like insertion or deletion may dispose buffers\n    in dirty state, and this needs to cancel the dirty state of their\n    pages.  clear_page_dirty_for_io() caused faults because it does not\n    clear the dirty tag on the page cache.\n\nSigned-off-by: Seiji Kihara \u003ckihara.seiji@lab.ntt.co.jp\u003e\nSigned-off-by: Ryusuke Konishi \u003ckonishi.ryusuke@lab.ntt.co.jp\u003e\nSigned-off-by: Andrew Morton \u003cakpm@linux-foundation.org\u003e\nSigned-off-by: Linus Torvalds \u003ctorvalds@linux-foundation.org\u003e\n"
    }
  ]
}