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ea1ab09df9
[CURRENT LIMIT] Btrfs currently only supports sub-bitmaps (e.g. dirty bitmap) no larger than BITS_PER_LONG. One call site that utilizes this limit is btrfs_bio_ctrl::submit_bitmap, which makes it very simple and straightforward to just grab an unsigned long value and assign it to submit_bitmap. Unfortunately that limit prevents us from supporting huge folios. For 4K page size and block size, a huge folio (order 9) means 512 blocks inside a 2M folio. [ENHANCEMENT] Instead of using a fixed unsigned long value, change btrfs_bio_ctrl::submit_bitmap to an unsigned long pointer. And for cases where an unsigned long can hold the whole bitmap, introduce @submit_bitmap_value, and just point that pointer to that unsigned long. Then update all direct users of bio_ctrl->submit_bitmap to use the pointer version. There are several call sites that get extra changes: - @range_bitmap inside extent_writepage_io() Which is only utilized to truncate the bitmap. Since we do not want to allocate new memory just for such temporary usage, change the original bitmap_set() and bitmap_and() into bitmap_clear() for the ranges outside of the target range. - Getting dirty subpage bitmap inside writepage_delalloc() Since we're passing an unsigned long pointer now, we need to go with different handling (bs == ps, blocks_per_folio <= BITS_PER_LONG, blocks_per_folio > BITS_PER_LONG). Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
193 lines
7 KiB
193 lines
7 KiB