mirror of https://github.com/vitalif/e2fsprogs
libext2fs: optimize find_first_{zero,set}() for red-black tree based bitmaps
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>maint-test
parent
14717832dd
commit
3203cd9332
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@ -809,6 +809,93 @@ static void rb_clear_bmap(ext2fs_generic_bitmap bitmap)
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check_tree(&bp->root, __func__);
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}
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static errcode_t rb_find_first_zero(ext2fs_generic_bitmap bitmap,
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__u64 start, __u64 end, __u64 *out)
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{
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struct rb_node *parent = NULL, **n;
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struct rb_node *node, *next;
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struct ext2fs_rb_private *bp;
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struct bmap_rb_extent *ext;
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int retval = 1;
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bp = (struct ext2fs_rb_private *) bitmap->private;
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n = &bp->root.rb_node;
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start -= bitmap->start;
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end -= bitmap->start;
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if (start > end)
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return EINVAL;
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if (EXT2FS_RB_EMPTY_ROOT(&bp->root))
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return ENOENT;
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while (*n) {
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parent = *n;
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ext = node_to_extent(parent);
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if (start < ext->start) {
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n = &(*n)->rb_left;
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} else if (start >= (ext->start + ext->count)) {
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n = &(*n)->rb_right;
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} else if (ext->start + ext->count <= end) {
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*out = ext->start + ext->count + bitmap->start;
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return 0;
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} else
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return ENOENT;
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}
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*out = start + bitmap->start;
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return 0;
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}
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static errcode_t rb_find_first_set(ext2fs_generic_bitmap bitmap,
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__u64 start, __u64 end, __u64 *out)
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{
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struct rb_node *parent = NULL, **n;
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struct rb_node *node, *next;
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struct ext2fs_rb_private *bp;
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struct bmap_rb_extent *ext;
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int retval = 1;
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bp = (struct ext2fs_rb_private *) bitmap->private;
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n = &bp->root.rb_node;
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start -= bitmap->start;
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end -= bitmap->start;
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if (start > end)
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return EINVAL;
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if (EXT2FS_RB_EMPTY_ROOT(&bp->root))
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return ENOENT;
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while (*n) {
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parent = *n;
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ext = node_to_extent(parent);
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if (start < ext->start) {
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n = &(*n)->rb_left;
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} else if (start >= (ext->start + ext->count)) {
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n = &(*n)->rb_right;
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} else {
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/* The start bit is set */
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*out = start + bitmap->start;
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return 0;
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}
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}
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node = parent;
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ext = node_to_extent(node);
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if (ext->start < start) {
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node = ext2fs_rb_next(node);
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if (node == NULL)
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return ENOENT;
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ext = node_to_extent(node);
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}
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if (ext->start <= end) {
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*out = ext->start + bitmap->start;
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return 0;
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}
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return ENOENT;
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}
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#ifdef BMAP_STATS
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static void rb_print_stats(ext2fs_generic_bitmap bitmap)
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{
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@ -890,4 +977,6 @@ struct ext2_bitmap_ops ext2fs_blkmap64_rbtree = {
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.get_bmap_range = rb_get_bmap_range,
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.clear_bmap = rb_clear_bmap,
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.print_stats = rb_print_stats,
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.find_first_zero = rb_find_first_zero,
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.find_first_set = rb_find_first_set,
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};
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