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    Subject[PATCH] rbtree: fix jffs2 build issue due to renamed __rb_parent_color field
    ... and clean up the comments to better explain why it's acceptable to
    do it this way instead of using rb_erase() "properly".

    Signed-off-by: David Woodhouse <>
    On Wed, 2012-07-18 at 12:40 +0100, David Woodhouse wrote:
    > If you're going to make that comment redundant, you might as well remove
    > it. And you might as well say that the trees are being *destroyed*
    > (consumed) at this point, rather than just that there will be no further
    > insert or erase operations.

    The comment on ver_insert() confused me too while I was looking at this,
    so I've improved that as well.

    A quick and dirty benchmark shows about a 10% performance improvement
    when mounting a RAM-backed JFFS2 file system on Westmere. Thanks.

    Acked-By: David Woodhouse <> for the rest of
    the series.

    diff --git a/fs/jffs2/readinode.c b/fs/jffs2/readinode.c
    index 1ea349f..ae81b01 100644
    --- a/fs/jffs2/readinode.c
    +++ b/fs/jffs2/readinode.c
    @@ -394,8 +394,11 @@ static int jffs2_add_tn_to_tree(struct jffs2_sb_info *c,

    /* Trivial function to remove the last node in the tree. Which by definition
    - has no right-hand -- so can be removed just by making its only child (if
    - any) take its place under its parent. */
    + has no right-hand child — so can be removed just by making its left-hand
    + child (if any) take its place under its parent. Since this is only done
    + when we're consuming the whole tree, there's no need to use rb_erase()
    + and let it worry about adjusting colours and balancing the tree. That
    + would just be a waste of time. */
    static void eat_last(struct rb_root *root, struct rb_node *node)
    struct rb_node *parent = rb_parent(node);
    @@ -412,12 +415,12 @@ static void eat_last(struct rb_root *root, struct rb_node *node)
    link = &parent->rb_right;

    *link = node->rb_left;
    - /* Colour doesn't matter now. Only the parent pointer. */
    if (node->rb_left)
    - node->rb_left->rb_parent_color = node->rb_parent_color;
    + node->rb_left->__rb_parent_color = node->__rb_parent_color;

    -/* We put this in reverse order, so we can just use eat_last */
    +/* We put the version tree in reverse order, so we can use the same eat_last()
    + function that we use to consume the tmpnode tree (tn_root). */
    static void ver_insert(struct rb_root *ver_root, struct jffs2_tmp_dnode_info *tn)
    struct rb_node **link = &ver_root->rb_node;
    [unhandled content-type:application/x-pkcs7-signature]
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      Last update: 2012-07-18 18:01    [W:0.025 / U:56.688 seconds]
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