btrfs: subpage: make extent_write_locked_range() compatible
There are two sites are not subpage compatible yet for extent_write_locked_range(): - How @nr_pages are calculated For subpage we can have the following range with 64K page size: 0 32K 64K 96K 128K | |////|/////| | In that case, although 96K - 32K == 64K, thus it looks like one page is enough, but the range spans two pages, not one. Fix it by doing proper round_up() and round_down() to calculate @nr_pages. Also add some extra ASSERT()s to ensure the range passed in is already aligned. - How the page end is calculated Currently we just use cur + PAGE_SIZE - 1 to calculate the page end. Which can't handle the above range layout, and will trigger ASSERT() in btrfs_writepage_endio_finish_ordered(), as the range is no longer covered by the page range. Fix it by taking page end into consideration. Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
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