14  * - Only support 64K page size for now
15  *   This is to make metadata handling easier, as 64K page would ensure
16  *   all nodesize would fit inside one page, thus we don't need to handle
22  * - Metadata can't cross 64K page boundary
32  *   needed range, other unrelated range in the same page will not be touched.
35  *   The writeback is still for the full page, but we will only submit
36  *   the dirty extent buffers in the page.
38  *   This means, if we have a metadata page like this:
40  *   Page offset
54  *   record the status of each sector inside a page.  This provides the extra
58  *   Since we have multiple tree blocks inside one page, we can't rely on page
61  *   the same page).
67 bool btrfs_is_subpage(const struct btrfs_fs_info *fs_info, struct page *page)  in btrfs_is_subpage()  argument
74 	 * mapping. And if page->mapping->host is data inode, it's subpage.  in btrfs_is_subpage()
77 	if (!page->mapping || !page->mapping->host ||  in btrfs_is_subpage()
78 	    is_data_inode(page->mapping->host))  in btrfs_is_subpage()
119 			 struct page *page, enum btrfs_subpage_type type)  in btrfs_attach_subpage()  argument
124 	 * We have cases like a dummy extent buffer page, which is not mapped  in btrfs_attach_subpage()
127 	if (page->mapping)  in btrfs_attach_subpage()
128 		ASSERT(PageLocked(page));  in btrfs_attach_subpage()
130 	/* Either not subpage, or the page already has private attached */  in btrfs_attach_subpage()
131 	if (!btrfs_is_subpage(fs_info, page) || PagePrivate(page))  in btrfs_attach_subpage()
138 	attach_page_private(page, subpage);  in btrfs_attach_subpage()
143 			  struct page *page)  in btrfs_detach_subpage()  argument
148 	if (!btrfs_is_subpage(fs_info, page) || !PagePrivate(page))  in btrfs_detach_subpage()
151 	subpage = detach_page_private(page);  in btrfs_detach_subpage()
189  * of the same page.
191  * detach_extent_buffer_page() won't detach the page private while we're still
195 			    struct page *page)  in btrfs_page_inc_eb_refs()  argument
199 	if (!btrfs_is_subpage(fs_info, page))  in btrfs_page_inc_eb_refs()
202 	ASSERT(PagePrivate(page) && page->mapping);  in btrfs_page_inc_eb_refs()
203 	lockdep_assert_held(&page->mapping->private_lock);  in btrfs_page_inc_eb_refs()
205 	subpage = (struct btrfs_subpage *)page->private;  in btrfs_page_inc_eb_refs()
210 			    struct page *page)  in btrfs_page_dec_eb_refs()  argument
214 	if (!btrfs_is_subpage(fs_info, page))  in btrfs_page_dec_eb_refs()
217 	ASSERT(PagePrivate(page) && page->mapping);  in btrfs_page_dec_eb_refs()
218 	lockdep_assert_held(&page->mapping->private_lock);  in btrfs_page_dec_eb_refs()
220 	subpage = (struct btrfs_subpage *)page->private;  in btrfs_page_dec_eb_refs()
226 		struct page *page, u64 start, u32 len)  in btrfs_subpage_assert()  argument
229 	ASSERT(PagePrivate(page) && page->private);  in btrfs_subpage_assert()
233 	 * The range check only works for mapped page, we can still have  in btrfs_subpage_assert()
234 	 * unmapped page like dummy extent buffer pages.  in btrfs_subpage_assert()
236 	if (page->mapping)  in btrfs_subpage_assert()
237 		ASSERT(page_offset(page) <= start &&  in btrfs_subpage_assert()
238 		       start + len <= page_offset(page) + PAGE_SIZE);  in btrfs_subpage_assert()
242 		struct page *page, u64 start, u32 len)  in btrfs_subpage_start_reader()  argument
244 	struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;  in btrfs_subpage_start_reader()
247 	btrfs_subpage_assert(fs_info, page, start, len);  in btrfs_subpage_start_reader()
253 		struct page *page, u64 start, u32 len)  in btrfs_subpage_end_reader()  argument
255 	struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;  in btrfs_subpage_end_reader()
260 	btrfs_subpage_assert(fs_info, page, start, len);  in btrfs_subpage_end_reader()
261 	is_data = is_data_inode(page->mapping->host);  in btrfs_subpage_end_reader()
266 	 * For data we need to unlock the page if the last read has finished.  in btrfs_subpage_end_reader()
273 		unlock_page(page);  in btrfs_subpage_end_reader()
276 static void btrfs_subpage_clamp_range(struct page *page, u64 *start, u32 *len)  in btrfs_subpage_clamp_range()  argument
281 	*start = max_t(u64, page_offset(page), orig_start);  in btrfs_subpage_clamp_range()
287 	if (page_offset(page) >= orig_start + orig_len)  in btrfs_subpage_clamp_range()
290 		*len = min_t(u64, page_offset(page) + PAGE_SIZE,  in btrfs_subpage_clamp_range()
295 		struct page *page, u64 start, u32 len)  in btrfs_subpage_start_writer()  argument
297 	struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;  in btrfs_subpage_start_writer()
301 	btrfs_subpage_assert(fs_info, page, start, len);  in btrfs_subpage_start_writer()
309 		struct page *page, u64 start, u32 len)  in btrfs_subpage_end_and_test_writer()  argument
311 	struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;  in btrfs_subpage_end_and_test_writer()
314 	btrfs_subpage_assert(fs_info, page, start, len);  in btrfs_subpage_end_and_test_writer()
331  * Lock a page for delalloc page writeback.
333  * Return -EAGAIN if the page is not properly initialized.
334  * Return 0 with the page locked, and writer counter updated.
336  * Even with 0 returned, the page still need extra check to make sure
337  * it's really the correct page, as the caller is using
338  * filemap_get_folios_contig(), which can race with page invalidating.
341 		struct page *page, u64 start, u32 len)  in btrfs_page_start_writer_lock()  argument
343 	if (unlikely(!fs_info) || !btrfs_is_subpage(fs_info, page)) {  in btrfs_page_start_writer_lock()
344 		lock_page(page);  in btrfs_page_start_writer_lock()
347 	lock_page(page);  in btrfs_page_start_writer_lock()
348 	if (!PagePrivate(page) || !page->private) {  in btrfs_page_start_writer_lock()
349 		unlock_page(page);  in btrfs_page_start_writer_lock()
352 	btrfs_subpage_clamp_range(page, &start, &len);  in btrfs_page_start_writer_lock()
353 	btrfs_subpage_start_writer(fs_info, page, start, len);  in btrfs_page_start_writer_lock()
358 		struct page *page, u64 start, u32 len)  in btrfs_page_end_writer_lock()  argument
360 	if (unlikely(!fs_info) || !btrfs_is_subpage(fs_info, page))  in btrfs_page_end_writer_lock()
361 		return unlock_page(page);  in btrfs_page_end_writer_lock()
362 	btrfs_subpage_clamp_range(page, &start, &len);  in btrfs_page_end_writer_lock()
363 	if (btrfs_subpage_end_and_test_writer(fs_info, page, start, len))  in btrfs_page_end_writer_lock()
364 		unlock_page(page);  in btrfs_page_end_writer_lock()
367 #define subpage_calc_start_bit(fs_info, page, name, start, len)		\  argument
371 	btrfs_subpage_assert(fs_info, page, start, len);		\
388 		struct page *page, u64 start, u32 len)  in btrfs_subpage_set_uptodate()  argument
390 	struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;  in btrfs_subpage_set_uptodate()
391 	unsigned int start_bit = subpage_calc_start_bit(fs_info, page,  in btrfs_subpage_set_uptodate()
398 		SetPageUptodate(page);  in btrfs_subpage_set_uptodate()
403 		struct page *page, u64 start, u32 len)  in btrfs_subpage_clear_uptodate()  argument
405 	struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;  in btrfs_subpage_clear_uptodate()
406 	unsigned int start_bit = subpage_calc_start_bit(fs_info, page,  in btrfs_subpage_clear_uptodate()
412 	ClearPageUptodate(page);  in btrfs_subpage_clear_uptodate()
417 		struct page *page, u64 start, u32 len)  in btrfs_subpage_set_dirty()  argument
419 	struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;  in btrfs_subpage_set_dirty()
420 	unsigned int start_bit = subpage_calc_start_bit(fs_info, page,  in btrfs_subpage_set_dirty()
427 	set_page_dirty(page);  in btrfs_subpage_set_dirty()
437  * NOTE: Callers should manually clear page dirty for true case, as we have
441 		struct page *page, u64 start, u32 len)  in btrfs_subpage_clear_and_test_dirty()  argument
443 	struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;  in btrfs_subpage_clear_and_test_dirty()
444 	unsigned int start_bit = subpage_calc_start_bit(fs_info, page,  in btrfs_subpage_clear_and_test_dirty()
458 		struct page *page, u64 start, u32 len)  in btrfs_subpage_clear_dirty()  argument
462 	last = btrfs_subpage_clear_and_test_dirty(fs_info, page, start, len);  in btrfs_subpage_clear_dirty()
464 		clear_page_dirty_for_io(page);  in btrfs_subpage_clear_dirty()
468 		struct page *page, u64 start, u32 len)  in btrfs_subpage_set_writeback()  argument
470 	struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;  in btrfs_subpage_set_writeback()
471 	unsigned int start_bit = subpage_calc_start_bit(fs_info, page,  in btrfs_subpage_set_writeback()
477 	set_page_writeback(page);  in btrfs_subpage_set_writeback()
482 		struct page *page, u64 start, u32 len)  in btrfs_subpage_clear_writeback()  argument
484 	struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;  in btrfs_subpage_clear_writeback()
485 	unsigned int start_bit = subpage_calc_start_bit(fs_info, page,  in btrfs_subpage_clear_writeback()
492 		ASSERT(PageWriteback(page));  in btrfs_subpage_clear_writeback()
493 		end_page_writeback(page);  in btrfs_subpage_clear_writeback()
499 		struct page *page, u64 start, u32 len)  in btrfs_subpage_set_ordered()  argument
501 	struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;  in btrfs_subpage_set_ordered()
502 	unsigned int start_bit = subpage_calc_start_bit(fs_info, page,  in btrfs_subpage_set_ordered()
508 	SetPageOrdered(page);  in btrfs_subpage_set_ordered()
513 		struct page *page, u64 start, u32 len)  in btrfs_subpage_clear_ordered()  argument
515 	struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;  in btrfs_subpage_clear_ordered()
516 	unsigned int start_bit = subpage_calc_start_bit(fs_info, page,  in btrfs_subpage_clear_ordered()
523 		ClearPageOrdered(page);  in btrfs_subpage_clear_ordered()
528 			       struct page *page, u64 start, u32 len)  in btrfs_subpage_set_checked()  argument
530 	struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;  in btrfs_subpage_set_checked()
531 	unsigned int start_bit = subpage_calc_start_bit(fs_info, page,  in btrfs_subpage_set_checked()
538 		SetPageChecked(page);  in btrfs_subpage_set_checked()
543 				 struct page *page, u64 start, u32 len)  in btrfs_subpage_clear_checked()  argument
545 	struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;  in btrfs_subpage_clear_checked()
546 	unsigned int start_bit = subpage_calc_start_bit(fs_info, page,  in btrfs_subpage_clear_checked()
552 	ClearPageChecked(page);  in btrfs_subpage_clear_checked()
557  * Unlike set/clear which is dependent on each page status, for test all bits
562 		struct page *page, u64 start, u32 len)			\
564 	struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private; \
565 	unsigned int start_bit = subpage_calc_start_bit(fs_info, page,	\
590 		struct page *page, u64 start, u32 len)			\
592 	if (unlikely(!fs_info) || !btrfs_is_subpage(fs_info, page)) {	\
593 		set_page_func(page);					\
596 	btrfs_subpage_set_##name(fs_info, page, start, len);		\
599 		struct page *page, u64 start, u32 len)			\
601 	if (unlikely(!fs_info) || !btrfs_is_subpage(fs_info, page)) {	\
602 		clear_page_func(page);					\
605 	btrfs_subpage_clear_##name(fs_info, page, start, len);		\
608 		struct page *page, u64 start, u32 len)			\
610 	if (unlikely(!fs_info) || !btrfs_is_subpage(fs_info, page))	\
611 		return test_page_func(page);				\
612 	return btrfs_subpage_test_##name(fs_info, page, start, len);	\
615 		struct page *page, u64 start, u32 len)			\
617 	if (unlikely(!fs_info) || !btrfs_is_subpage(fs_info, page)) {	\
618 		set_page_func(page);					\
621 	btrfs_subpage_clamp_range(page, &start, &len);			\
622 	btrfs_subpage_set_##name(fs_info, page, start, len);		\
625 		struct page *page, u64 start, u32 len)			\
627 	if (unlikely(!fs_info) || !btrfs_is_subpage(fs_info, page)) {	\
628 		clear_page_func(page);					\
631 	btrfs_subpage_clamp_range(page, &start, &len);			\
632 	btrfs_subpage_clear_##name(fs_info, page, start, len);		\
635 		struct page *page, u64 start, u32 len)			\
637 	if (unlikely(!fs_info) || !btrfs_is_subpage(fs_info, page))	\
638 		return test_page_func(page);				\
639 	btrfs_subpage_clamp_range(page, &start, &len);			\
640 	return btrfs_subpage_test_##name(fs_info, page, start, len);	\
653  * Make sure not only the page dirty bit is cleared, but also subpage dirty bit
657 				 struct page *page)  in btrfs_page_assert_not_dirty()  argument
659 	struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;  in btrfs_page_assert_not_dirty()
664 	ASSERT(!PageDirty(page));  in btrfs_page_assert_not_dirty()
665 	if (!btrfs_is_subpage(fs_info, page))  in btrfs_page_assert_not_dirty()
668 	ASSERT(PagePrivate(page) && page->private);  in btrfs_page_assert_not_dirty()
673  * Handle different locked pages with different page sizes:
675  * - Page locked by plain lock_page()
678  *   This is the most common locked page for __extent_writepage() called
682  * - Page locked by lock_delalloc_pages()
687 void btrfs_page_unlock_writer(struct btrfs_fs_info *fs_info, struct page *page,  in btrfs_page_unlock_writer()  argument
692 	ASSERT(PageLocked(page));  in btrfs_page_unlock_writer()
693 	/* For non-subpage case, we just unlock the page */  in btrfs_page_unlock_writer()
694 	if (!btrfs_is_subpage(fs_info, page))  in btrfs_page_unlock_writer()
695 		return unlock_page(page);  in btrfs_page_unlock_writer()
697 	ASSERT(PagePrivate(page) && page->private);  in btrfs_page_unlock_writer()
698 	subpage = (struct btrfs_subpage *)page->private;  in btrfs_page_unlock_writer()
701 	 * For subpage case, there are two types of locked page.  With or  in btrfs_page_unlock_writer()
704 	 * Since we own the page lock, no one else could touch subpage::writers  in btrfs_page_unlock_writer()
709 		return unlock_page(page);  in btrfs_page_unlock_writer()
712 	btrfs_page_end_writer_lock(fs_info, page, start, len);  in btrfs_page_unlock_writer()
720 				      struct page *page, u64 start, u32 len)  in btrfs_subpage_dump_bitmap()  argument
732 	ASSERT(PagePrivate(page) && page->private);  in btrfs_subpage_dump_bitmap()
734 	subpage = (struct btrfs_subpage *)page->private;  in btrfs_subpage_dump_bitmap()
744 	dump_page(page, "btrfs subpage dump");  in btrfs_subpage_dump_bitmap()
746 "start=%llu len=%u page=%llu, bitmaps uptodate=%*pbl error=%*pbl dirty=%*pbl writeback=%*pbl ordere…  in btrfs_subpage_dump_bitmap()
747 		    start, len, page_offset(page),  in btrfs_subpage_dump_bitmap()