diff options
Diffstat (limited to 'fs/btrfs/extent_io.c')
| -rw-r--r-- | fs/btrfs/extent_io.c | 52 |
1 files changed, 46 insertions, 6 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 9591ecfaa57e..105b3d2e86f2 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -1537,8 +1537,8 @@ out: } /** - * find_first_clear_extent_bit - finds the first range that has @bits not set - * and that starts after @start + * find_first_clear_extent_bit - find the first range that has @bits not set. + * This range could start before @start. * * @tree - the tree to search * @start - the offset at/after which the found extent should start @@ -1578,12 +1578,52 @@ void find_first_clear_extent_bit(struct extent_io_tree *tree, u64 start, goto out; } } + /* + * At this point 'node' either contains 'start' or start is + * before 'node' + */ state = rb_entry(node, struct extent_state, rb_node); - if (in_range(start, state->start, state->end - state->start + 1) && - (state->state & bits)) { - start = state->end + 1; + + if (in_range(start, state->start, state->end - state->start + 1)) { + if (state->state & bits) { + /* + * |--range with bits sets--| + * | + * start + */ + start = state->end + 1; + } else { + /* + * 'start' falls within a range that doesn't + * have the bits set, so take its start as + * the beginning of the desired range + * + * |--range with bits cleared----| + * | + * start + */ + *start_ret = state->start; + break; + } } else { - *start_ret = start; + /* + * |---prev range---|---hole/unset---|---node range---| + * | + * start + * + * or + * + * |---hole/unset--||--first node--| + * 0 | + * start + */ + if (prev) { + state = rb_entry(prev, struct extent_state, + rb_node); + *start_ret = state->end + 1; + } else { + *start_ret = 0; + } break; } } |