Merging upstream version 6.8.9.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 828 insertions, 525 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 87082f9732..b5175b9929 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -184,29 +184,30 @@ static void process_one_page(struct btrfs_fs_info *fs_info,
 			     struct page *page, struct page *locked_page,
 			     unsigned long page_ops, u64 start, u64 end)
 {
+	struct folio *folio = page_folio(page);
 	u32 len;
 
 	ASSERT(end + 1 - start != 0 && end + 1 - start < U32_MAX);
 	len = end + 1 - start;
 
 	if (page_ops & PAGE_SET_ORDERED)
-		btrfs_page_clamp_set_ordered(fs_info, page, start, len);
+		btrfs_folio_clamp_set_ordered(fs_info, folio, start, len);
 	if (page_ops & PAGE_START_WRITEBACK) {
-		btrfs_page_clamp_clear_dirty(fs_info, page, start, len);
-		btrfs_page_clamp_set_writeback(fs_info, page, start, len);
+		btrfs_folio_clamp_clear_dirty(fs_info, folio, start, len);
+		btrfs_folio_clamp_set_writeback(fs_info, folio, start, len);
 	}
 	if (page_ops & PAGE_END_WRITEBACK)
-		btrfs_page_clamp_clear_writeback(fs_info, page, start, len);
+		btrfs_folio_clamp_clear_writeback(fs_info, folio, start, len);
 
 	if (page != locked_page && (page_ops & PAGE_UNLOCK))
-		btrfs_page_end_writer_lock(fs_info, page, start, len);
+		btrfs_folio_end_writer_lock(fs_info, folio, start, len);
 }
 
 static void __process_pages_contig(struct address_space *mapping,
 				   struct page *locked_page, u64 start, u64 end,
 				   unsigned long page_ops)
 {
-	struct btrfs_fs_info *fs_info = btrfs_sb(mapping->host->i_sb);
+	struct btrfs_fs_info *fs_info = inode_to_fs_info(mapping->host);
 	pgoff_t start_index = start >> PAGE_SHIFT;
 	pgoff_t end_index = end >> PAGE_SHIFT;
 	pgoff_t index = start_index;
@@ -250,7 +251,7 @@ static noinline int lock_delalloc_pages(struct inode *inode,
 					u64 start,
 					u64 end)
 {
-	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
 	struct address_space *mapping = inode->i_mapping;
 	pgoff_t start_index = start >> PAGE_SHIFT;
 	pgoff_t end_index = end >> PAGE_SHIFT;
@@ -271,19 +272,20 @@ static noinline int lock_delalloc_pages(struct inode *inode,
 			goto out;
 
 		for (i = 0; i < found_folios; i++) {
-			struct page *page = &fbatch.folios[i]->page;
+			struct folio *folio = fbatch.folios[i];
+			struct page *page = folio_page(folio, 0);
 			u32 len = end + 1 - start;
 
 			if (page == locked_page)
 				continue;
 
-			if (btrfs_page_start_writer_lock(fs_info, page, start,
-							 len))
+			if (btrfs_folio_start_writer_lock(fs_info, folio, start,
+							  len))
 				goto out;
 
 			if (!PageDirty(page) || page->mapping != mapping) {
-				btrfs_page_end_writer_lock(fs_info, page, start,
-							   len);
+				btrfs_folio_end_writer_lock(fs_info, folio, start,
+							    len);
 				goto out;
 			}
 
@@ -321,7 +323,7 @@ noinline_for_stack bool find_lock_delalloc_range(struct inode *inode,
 				    struct page *locked_page, u64 *start,
 				    u64 *end)
 {
-	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
 	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
 	const u64 orig_start = *start;
 	const u64 orig_end = *end;
@@ -431,61 +433,66 @@ static bool btrfs_verify_page(struct page *page, u64 start)
 
 static void end_page_read(struct page *page, bool uptodate, u64 start, u32 len)
 {
-	struct btrfs_fs_info *fs_info = btrfs_sb(page->mapping->host->i_sb);
+	struct btrfs_fs_info *fs_info = page_to_fs_info(page);
+	struct folio *folio = page_folio(page);
 
 	ASSERT(page_offset(page) <= start &&
 	       start + len <= page_offset(page) + PAGE_SIZE);
 
 	if (uptodate && btrfs_verify_page(page, start))
-		btrfs_page_set_uptodate(fs_info, page, start, len);
+		btrfs_folio_set_uptodate(fs_info, folio, start, len);
 	else
-		btrfs_page_clear_uptodate(fs_info, page, start, len);
+		btrfs_folio_clear_uptodate(fs_info, folio, start, len);
 
-	if (!btrfs_is_subpage(fs_info, page))
+	if (!btrfs_is_subpage(fs_info, page->mapping))
 		unlock_page(page);
 	else
-		btrfs_subpage_end_reader(fs_info, page, start, len);
+		btrfs_subpage_end_reader(fs_info, folio, start, len);
 }
 
 /*
- * after a writepage IO is done, we need to:
- * clear the uptodate bits on error
- * clear the writeback bits in the extent tree for this IO
- * end_page_writeback if the page has no more pending IO
+ * After a write IO is done, we need to:
+ *
+ * - clear the uptodate bits on error
+ * - clear the writeback bits in the extent tree for the range
+ * - filio_end_writeback()  if there is no more pending io for the folio
  *
  * Scheduling is not allowed, so the extent state tree is expected
  * to have one and only one object corresponding to this IO.
  */
-static void end_bio_extent_writepage(struct btrfs_bio *bbio)
+static void end_bbio_data_write(struct btrfs_bio *bbio)
 {
 	struct bio *bio = &bbio->bio;
 	int error = blk_status_to_errno(bio->bi_status);
-	struct bio_vec *bvec;
-	struct bvec_iter_all iter_all;
+	struct folio_iter fi;
 
 	ASSERT(!bio_flagged(bio, BIO_CLONED));
-	bio_for_each_segment_all(bvec, bio, iter_all) {
-		struct page *page = bvec->bv_page;
-		struct inode *inode = page->mapping->host;
+	bio_for_each_folio_all(fi, bio) {
+		struct folio *folio = fi.folio;
+		struct inode *inode = folio->mapping->host;
 		struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 		const u32 sectorsize = fs_info->sectorsize;
-		u64 start = page_offset(page) + bvec->bv_offset;
-		u32 len = bvec->bv_len;
+		u64 start = folio_pos(folio) + fi.offset;
+		u32 len = fi.length;
+
+		/* Only order 0 (single page) folios are allowed for data. */
+		ASSERT(folio_order(folio) == 0);
 
 		/* Our read/write should always be sector aligned. */
-		if (!IS_ALIGNED(bvec->bv_offset, sectorsize))
+		if (!IS_ALIGNED(fi.offset, sectorsize))
 			btrfs_err(fs_info,
-		"partial page write in btrfs with offset %u and length %u",
-				  bvec->bv_offset, bvec->bv_len);
-		else if (!IS_ALIGNED(bvec->bv_len, sectorsize))
+		"partial page write in btrfs with offset %zu and length %zu",
+				  fi.offset, fi.length);
+		else if (!IS_ALIGNED(fi.length, sectorsize))
 			btrfs_info(fs_info,
-		"incomplete page write with offset %u and length %u",
-				   bvec->bv_offset, bvec->bv_len);
+		"incomplete page write with offset %zu and length %zu",
+				   fi.offset, fi.length);
 
-		btrfs_finish_ordered_extent(bbio->ordered, page, start, len, !error);
+		btrfs_finish_ordered_extent(bbio->ordered,
+				folio_page(folio, 0), start, len, !error);
 		if (error)
-			mapping_set_error(page->mapping, error);
-		btrfs_page_clear_writeback(fs_info, page, start, len);
+			mapping_set_error(folio->mapping, error);
+		btrfs_folio_clear_writeback(fs_info, folio, start, len);
 	}
 
 	bio_put(bio);
@@ -562,98 +569,102 @@ update:
 
 static void begin_page_read(struct btrfs_fs_info *fs_info, struct page *page)
 {
-	ASSERT(PageLocked(page));
-	if (!btrfs_is_subpage(fs_info, page))
+	struct folio *folio = page_folio(page);
+
+	ASSERT(folio_test_locked(folio));
+	if (!btrfs_is_subpage(fs_info, folio->mapping))
 		return;
 
-	ASSERT(PagePrivate(page));
-	btrfs_subpage_start_reader(fs_info, page, page_offset(page), PAGE_SIZE);
+	ASSERT(folio_test_private(folio));
+	btrfs_subpage_start_reader(fs_info, folio, page_offset(page), PAGE_SIZE);
 }
 
 /*
- * after a readpage IO is done, we need to:
- * clear the uptodate bits on error
- * set the uptodate bits if things worked
- * set the page up to date if all extents in the tree are uptodate
- * clear the lock bit in the extent tree
- * unlock the page if there are no other extents locked for it
+ * After a data read IO is done, we need to:
+ *
+ * - clear the uptodate bits on error
+ * - set the uptodate bits if things worked
+ * - set the folio up to date if all extents in the tree are uptodate
+ * - clear the lock bit in the extent tree
+ * - unlock the folio if there are no other extents locked for it
  *
  * Scheduling is not allowed, so the extent state tree is expected
  * to have one and only one object corresponding to this IO.
  */
-static void end_bio_extent_readpage(struct btrfs_bio *bbio)
+static void end_bbio_data_read(struct btrfs_bio *bbio)
 {
 	struct bio *bio = &bbio->bio;
-	struct bio_vec *bvec;
 	struct processed_extent processed = { 0 };
+	struct folio_iter fi;
 	/*
 	 * The offset to the beginning of a bio, since one bio can never be
 	 * larger than UINT_MAX, u32 here is enough.
 	 */
 	u32 bio_offset = 0;
-	struct bvec_iter_all iter_all;
 
 	ASSERT(!bio_flagged(bio, BIO_CLONED));
-	bio_for_each_segment_all(bvec, bio, iter_all) {
+	bio_for_each_folio_all(fi, &bbio->bio) {
 		bool uptodate = !bio->bi_status;
-		struct page *page = bvec->bv_page;
-		struct inode *inode = page->mapping->host;
+		struct folio *folio = fi.folio;
+		struct inode *inode = folio->mapping->host;
 		struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 		const u32 sectorsize = fs_info->sectorsize;
 		u64 start;
 		u64 end;
 		u32 len;
 
+		/* For now only order 0 folios are supported for data. */
+		ASSERT(folio_order(folio) == 0);
 		btrfs_debug(fs_info,
-			"end_bio_extent_readpage: bi_sector=%llu, err=%d, mirror=%u",
-			bio->bi_iter.bi_sector, bio->bi_status,
+			"%s: bi_sector=%llu, err=%d, mirror=%u",
+			__func__, bio->bi_iter.bi_sector, bio->bi_status,
 			bbio->mirror_num);
 
 		/*
 		 * We always issue full-sector reads, but if some block in a
-		 * page fails to read, blk_update_request() will advance
+		 * folio fails to read, blk_update_request() will advance
 		 * bv_offset and adjust bv_len to compensate.  Print a warning
 		 * for unaligned offsets, and an error if they don't add up to
 		 * a full sector.
 		 */
-		if (!IS_ALIGNED(bvec->bv_offset, sectorsize))
+		if (!IS_ALIGNED(fi.offset, sectorsize))
 			btrfs_err(fs_info,
-		"partial page read in btrfs with offset %u and length %u",
-				  bvec->bv_offset, bvec->bv_len);
-		else if (!IS_ALIGNED(bvec->bv_offset + bvec->bv_len,
-				     sectorsize))
+		"partial page read in btrfs with offset %zu and length %zu",
+				  fi.offset, fi.length);
+		else if (!IS_ALIGNED(fi.offset + fi.length, sectorsize))
 			btrfs_info(fs_info,
-		"incomplete page read with offset %u and length %u",
-				   bvec->bv_offset, bvec->bv_len);
+		"incomplete page read with offset %zu and length %zu",
+				   fi.offset, fi.length);
 
-		start = page_offset(page) + bvec->bv_offset;
-		end = start + bvec->bv_len - 1;
-		len = bvec->bv_len;
+		start = folio_pos(folio) + fi.offset;
+		end = start + fi.length - 1;
+		len = fi.length;
 
 		if (likely(uptodate)) {
 			loff_t i_size = i_size_read(inode);
-			pgoff_t end_index = i_size >> PAGE_SHIFT;
+			pgoff_t end_index = i_size >> folio_shift(folio);
 
 			/*
 			 * Zero out the remaining part if this range straddles
 			 * i_size.
 			 *
-			 * Here we should only zero the range inside the bvec,
+			 * Here we should only zero the range inside the folio,
 			 * not touch anything else.
 			 *
 			 * NOTE: i_size is exclusive while end is inclusive.
 			 */
-			if (page->index == end_index && i_size <= end) {
-				u32 zero_start = max(offset_in_page(i_size),
-						     offset_in_page(start));
+			if (folio_index(folio) == end_index && i_size <= end) {
+				u32 zero_start = max(offset_in_folio(folio, i_size),
+						     offset_in_folio(folio, start));
+				u32 zero_len = offset_in_folio(folio, end) + 1 -
+					       zero_start;
 
-				zero_user_segment(page, zero_start,
-						  offset_in_page(end) + 1);
+				folio_zero_range(folio, zero_start, zero_len);
 			}
 		}
 
 		/* Update page status and unlock. */
-		end_page_read(page, uptodate, start, len);
+		end_page_read(folio_page(folio, 0), uptodate, start, len);
 		endio_readpage_release_extent(&processed, BTRFS_I(inode),
 					      start, end, uptodate);
 
@@ -672,41 +683,54 @@ static void end_bio_extent_readpage(struct btrfs_bio *bbio)
  * @nr_pages:   number of pages to allocate
  * @page_array: the array to fill with pages; any existing non-null entries in
  * 		the array will be skipped
+ * @extra_gfp:	the extra GFP flags for the allocation.
  *
  * Return: 0        if all pages were able to be allocated;
  *         -ENOMEM  otherwise, the partially allocated pages would be freed and
  *                  the array slots zeroed
  */
-int btrfs_alloc_page_array(unsigned int nr_pages, struct page **page_array)
+int btrfs_alloc_page_array(unsigned int nr_pages, struct page **page_array,
+			   gfp_t extra_gfp)
 {
+	const gfp_t gfp = GFP_NOFS | extra_gfp;
 	unsigned int allocated;
 
 	for (allocated = 0; allocated < nr_pages;) {
 		unsigned int last = allocated;
 
-		allocated = alloc_pages_bulk_array(GFP_NOFS, nr_pages, page_array);
-
-		if (allocated == nr_pages)
-			return 0;
-
-		/*
-		 * During this iteration, no page could be allocated, even
-		 * though alloc_pages_bulk_array() falls back to alloc_page()
-		 * if  it could not bulk-allocate. So we must be out of memory.
-		 */
-		if (allocated == last) {
+		allocated = alloc_pages_bulk_array(gfp, nr_pages, page_array);
+		if (unlikely(allocated == last)) {
+			/* No progress, fail and do cleanup. */
 			for (int i = 0; i < allocated; i++) {
 				__free_page(page_array[i]);
 				page_array[i] = NULL;
 			}
 			return -ENOMEM;
 		}
-
-		memalloc_retry_wait(GFP_NOFS);
 	}
 	return 0;
 }
 
+/*
+ * Populate needed folios for the extent buffer.
+ *
+ * For now, the folios populated are always in order 0 (aka, single page).
+ */
+static int alloc_eb_folio_array(struct extent_buffer *eb, gfp_t extra_gfp)
+{
+	struct page *page_array[INLINE_EXTENT_BUFFER_PAGES] = { 0 };
+	int num_pages = num_extent_pages(eb);
+	int ret;
+
+	ret = btrfs_alloc_page_array(num_pages, page_array, extra_gfp);
+	if (ret < 0)
+		return ret;
+
+	for (int i = 0; i < num_pages; i++)
+		eb->folios[i] = page_folio(page_array[i]);
+	return 0;
+}
+
 static bool btrfs_bio_is_contig(struct btrfs_bio_ctrl *bio_ctrl,
 				struct page *page, u64 disk_bytenr,
 				unsigned int pg_offset)
@@ -793,7 +817,7 @@ static void submit_extent_page(struct btrfs_bio_ctrl *bio_ctrl,
 			       u64 disk_bytenr, struct page *page,
 			       size_t size, unsigned long pg_offset)
 {
-	struct btrfs_inode *inode = BTRFS_I(page->mapping->host);
+	struct btrfs_inode *inode = page_to_inode(page);
 
 	ASSERT(pg_offset + size <= PAGE_SIZE);
 	ASSERT(bio_ctrl->end_io_func);
@@ -861,9 +885,9 @@ static void submit_extent_page(struct btrfs_bio_ctrl *bio_ctrl,
 	} while (size);
 }
 
-static int attach_extent_buffer_page(struct extent_buffer *eb,
-				     struct page *page,
-				     struct btrfs_subpage *prealloc)
+static int attach_extent_buffer_folio(struct extent_buffer *eb,
+				      struct folio *folio,
+				      struct btrfs_subpage *prealloc)
 {
 	struct btrfs_fs_info *fs_info = eb->fs_info;
 	int ret = 0;
@@ -874,65 +898,70 @@ static int attach_extent_buffer_page(struct extent_buffer *eb,
 	 * For cloned or dummy extent buffers, their pages are not mapped and
 	 * will not race with any other ebs.
 	 */
-	if (page->mapping)
-		lockdep_assert_held(&page->mapping->private_lock);
+	if (folio->mapping)
+		lockdep_assert_held(&folio->mapping->i_private_lock);
 
 	if (fs_info->nodesize >= PAGE_SIZE) {
-		if (!PagePrivate(page))
-			attach_page_private(page, eb);
+		if (!folio_test_private(folio))
+			folio_attach_private(folio, eb);
 		else
-			WARN_ON(page->private != (unsigned long)eb);
+			WARN_ON(folio_get_private(folio) != eb);
 		return 0;
 	}
 
 	/* Already mapped, just free prealloc */
-	if (PagePrivate(page)) {
+	if (folio_test_private(folio)) {
 		btrfs_free_subpage(prealloc);
 		return 0;
 	}
 
 	if (prealloc)
 		/* Has preallocated memory for subpage */
-		attach_page_private(page, prealloc);
+		folio_attach_private(folio, prealloc);
 	else
 		/* Do new allocation to attach subpage */
-		ret = btrfs_attach_subpage(fs_info, page,
-					   BTRFS_SUBPAGE_METADATA);
+		ret = btrfs_attach_subpage(fs_info, folio, BTRFS_SUBPAGE_METADATA);
 	return ret;
 }
 
 int set_page_extent_mapped(struct page *page)
 {
+	return set_folio_extent_mapped(page_folio(page));
+}
+
+int set_folio_extent_mapped(struct folio *folio)
+{
 	struct btrfs_fs_info *fs_info;
 
-	ASSERT(page->mapping);
+	ASSERT(folio->mapping);
 
-	if (PagePrivate(page))
+	if (folio_test_private(folio))
 		return 0;
 
-	fs_info = btrfs_sb(page->mapping->host->i_sb);
+	fs_info = folio_to_fs_info(folio);
 
-	if (btrfs_is_subpage(fs_info, page))
-		return btrfs_attach_subpage(fs_info, page, BTRFS_SUBPAGE_DATA);
+	if (btrfs_is_subpage(fs_info, folio->mapping))
+		return btrfs_attach_subpage(fs_info, folio, BTRFS_SUBPAGE_DATA);
 
-	attach_page_private(page, (void *)EXTENT_PAGE_PRIVATE);
+	folio_attach_private(folio, (void *)EXTENT_FOLIO_PRIVATE);
 	return 0;
 }
 
 void clear_page_extent_mapped(struct page *page)
 {
+	struct folio *folio = page_folio(page);
 	struct btrfs_fs_info *fs_info;
 
 	ASSERT(page->mapping);
 
-	if (!PagePrivate(page))
+	if (!folio_test_private(folio))
 		return;
 
-	fs_info = btrfs_sb(page->mapping->host->i_sb);
-	if (btrfs_is_subpage(fs_info, page))
-		return btrfs_detach_subpage(fs_info, page);
+	fs_info = page_to_fs_info(page);
+	if (btrfs_is_subpage(fs_info, page->mapping))
+		return btrfs_detach_subpage(fs_info, folio);
 
-	detach_page_private(page);
+	folio_detach_private(folio);
 }
 
 static struct extent_map *
@@ -972,7 +1001,7 @@ static int btrfs_do_readpage(struct page *page, struct extent_map **em_cached,
 		      struct btrfs_bio_ctrl *bio_ctrl, u64 *prev_em_start)
 {
 	struct inode *inode = page->mapping->host;
-	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
 	u64 start = page_offset(page);
 	const u64 end = start + PAGE_SIZE - 1;
 	u64 cur = start;
@@ -983,7 +1012,7 @@ static int btrfs_do_readpage(struct page *page, struct extent_map **em_cached,
 	int ret = 0;
 	size_t pg_offset = 0;
 	size_t iosize;
-	size_t blocksize = inode->i_sb->s_blocksize;
+	size_t blocksize = fs_info->sectorsize;
 	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
 
 	ret = set_page_extent_mapped(page);
@@ -1001,7 +1030,7 @@ static int btrfs_do_readpage(struct page *page, struct extent_map **em_cached,
 			memzero_page(page, zero_offset, iosize);
 		}
 	}
-	bio_ctrl->end_io_func = end_bio_extent_readpage;
+	bio_ctrl->end_io_func = end_bbio_data_read;
 	begin_page_read(fs_info, page);
 	while (cur <= end) {
 		enum btrfs_compression_type compress_type = BTRFS_COMPRESS_NONE;
@@ -1027,8 +1056,7 @@ static int btrfs_do_readpage(struct page *page, struct extent_map **em_cached,
 		BUG_ON(extent_map_end(em) <= cur);
 		BUG_ON(end < cur);
 
-		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
-			compress_type = em->compress_type;
+		compress_type = extent_map_compression(em);
 
 		iosize = min(extent_map_end(em) - cur, end - cur + 1);
 		iosize = ALIGN(iosize, blocksize);
@@ -1037,7 +1065,7 @@ static int btrfs_do_readpage(struct page *page, struct extent_map **em_cached,
 		else
 			disk_bytenr = em->block_start + extent_offset;
 		block_start = em->block_start;
-		if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
+		if (em->flags & EXTENT_FLAG_PREALLOC)
 			block_start = EXTENT_MAP_HOLE;
 
 		/*
@@ -1074,7 +1102,7 @@ static int btrfs_do_readpage(struct page *page, struct extent_map **em_cached,
 		 * is a corner case so we prioritize correctness over
 		 * non-optimal behavior (submitting 2 bios for the same extent).
 		 */
-		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) &&
+		if (compress_type != BTRFS_COMPRESS_NONE &&
 		    prev_em_start && *prev_em_start != (u64)-1 &&
 		    *prev_em_start != em->start)
 			force_bio_submit = true;
@@ -1123,7 +1151,7 @@ static int btrfs_do_readpage(struct page *page, struct extent_map **em_cached,
 int btrfs_read_folio(struct file *file, struct folio *folio)
 {
 	struct page *page = &folio->page;
-	struct btrfs_inode *inode = BTRFS_I(page->mapping->host);
+	struct btrfs_inode *inode = page_to_inode(page);
 	u64 start = page_offset(page);
 	u64 end = start + PAGE_SIZE - 1;
 	struct btrfs_bio_ctrl bio_ctrl = { .opf = REQ_OP_READ };
@@ -1146,7 +1174,7 @@ static inline void contiguous_readpages(struct page *pages[], int nr_pages,
 					struct btrfs_bio_ctrl *bio_ctrl,
 					u64 *prev_em_start)
 {
-	struct btrfs_inode *inode = BTRFS_I(pages[0]->mapping->host);
+	struct btrfs_inode *inode = page_to_inode(pages[0]);
 	int index;
 
 	btrfs_lock_and_flush_ordered_range(inode, start, end, NULL);
@@ -1240,7 +1268,8 @@ static noinline_for_stack int writepage_delalloc(struct btrfs_inode *inode,
 static void find_next_dirty_byte(struct btrfs_fs_info *fs_info,
 				 struct page *page, u64 *start, u64 *end)
 {
-	struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;
+	struct folio *folio = page_folio(page);
+	struct btrfs_subpage *subpage = folio_get_private(folio);
 	struct btrfs_subpage_info *spi = fs_info->subpage_info;
 	u64 orig_start = *start;
 	/* Declare as unsigned long so we can use bitmap ops */
@@ -1252,7 +1281,7 @@ static void find_next_dirty_byte(struct btrfs_fs_info *fs_info,
 	 * For regular sector size == page size case, since one page only
 	 * contains one sector, we return the page offset directly.
 	 */
-	if (!btrfs_is_subpage(fs_info, page)) {
+	if (!btrfs_is_subpage(fs_info, page->mapping)) {
 		*start = page_offset(page);
 		*end = page_offset(page) + PAGE_SIZE;
 		return;
@@ -1305,7 +1334,7 @@ static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode,
 		return 1;
 	}
 
-	bio_ctrl->end_io_func = end_bio_extent_writepage;
+	bio_ctrl->end_io_func = end_bbio_data_write;
 	while (cur <= end) {
 		u32 len = end - cur + 1;
 		u64 disk_bytenr;
@@ -1325,7 +1354,7 @@ static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode,
 			 * writeback the sectors with subpage dirty bits,
 			 * causing writeback without ordered extent.
 			 */
-			btrfs_page_clear_dirty(fs_info, page, cur, len);
+			btrfs_folio_clear_dirty(fs_info, page_folio(page), cur, len);
 			break;
 		}
 
@@ -1352,7 +1381,7 @@ static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode,
 		block_start = em->block_start;
 		disk_bytenr = em->block_start + extent_offset;
 
-		ASSERT(!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags));
+		ASSERT(!extent_map_is_compressed(em));
 		ASSERT(block_start != EXTENT_MAP_HOLE);
 		ASSERT(block_start != EXTENT_MAP_INLINE);
 
@@ -1377,7 +1406,7 @@ static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode,
 		 * So clear subpage dirty bit here so next time we won't submit
 		 * page for range already written to disk.
 		 */
-		btrfs_page_clear_dirty(fs_info, page, cur, iosize);
+		btrfs_folio_clear_dirty(fs_info, page_folio(page), cur, iosize);
 
 		submit_extent_page(bio_ctrl, disk_bytenr, page, iosize,
 				   cur - page_offset(page));
@@ -1385,7 +1414,7 @@ static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode,
 		nr++;
 	}
 
-	btrfs_page_assert_not_dirty(fs_info, page);
+	btrfs_folio_assert_not_dirty(fs_info, page_folio(page));
 	*nr_ret = nr;
 	return 0;
 
@@ -1607,24 +1636,23 @@ static struct extent_buffer *find_extent_buffer_nolock(
 	return NULL;
 }
 
-static void extent_buffer_write_end_io(struct btrfs_bio *bbio)
+static void end_bbio_meta_write(struct btrfs_bio *bbio)
 {
 	struct extent_buffer *eb = bbio->private;
 	struct btrfs_fs_info *fs_info = eb->fs_info;
 	bool uptodate = !bbio->bio.bi_status;
-	struct bvec_iter_all iter_all;
-	struct bio_vec *bvec;
+	struct folio_iter fi;
 	u32 bio_offset = 0;
 
 	if (!uptodate)
 		set_btree_ioerr(eb);
 
-	bio_for_each_segment_all(bvec, &bbio->bio, iter_all) {
+	bio_for_each_folio_all(fi, &bbio->bio) {
 		u64 start = eb->start + bio_offset;
-		struct page *page = bvec->bv_page;
-		u32 len = bvec->bv_len;
+		struct folio *folio = fi.folio;
+		u32 len = fi.length;
 
-		btrfs_page_clear_writeback(fs_info, page, start, len);
+		btrfs_folio_clear_writeback(fs_info, folio, start, len);
 		bio_offset += len;
 	}
 
@@ -1673,36 +1701,44 @@ static noinline_for_stack void write_one_eb(struct extent_buffer *eb,
 
 	bbio = btrfs_bio_alloc(INLINE_EXTENT_BUFFER_PAGES,
 			       REQ_OP_WRITE | REQ_META | wbc_to_write_flags(wbc),
-			       eb->fs_info, extent_buffer_write_end_io, eb);
+			       eb->fs_info, end_bbio_meta_write, eb);
 	bbio->bio.bi_iter.bi_sector = eb->start >> SECTOR_SHIFT;
 	bio_set_dev(&bbio->bio, fs_info->fs_devices->latest_dev->bdev);
 	wbc_init_bio(wbc, &bbio->bio);
 	bbio->inode = BTRFS_I(eb->fs_info->btree_inode);
 	bbio->file_offset = eb->start;
 	if (fs_info->nodesize < PAGE_SIZE) {
-		struct page *p = eb->pages[0];
+		struct folio *folio = eb->folios[0];
+		bool ret;
 
-		lock_page(p);
-		btrfs_subpage_set_writeback(fs_info, p, eb->start, eb->len);
-		if (btrfs_subpage_clear_and_test_dirty(fs_info, p, eb->start,
+		folio_lock(folio);
+		btrfs_subpage_set_writeback(fs_info, folio, eb->start, eb->len);
+		if (btrfs_subpage_clear_and_test_dirty(fs_info, folio, eb->start,
 						       eb->len)) {
-			clear_page_dirty_for_io(p);
+			folio_clear_dirty_for_io(folio);
 			wbc->nr_to_write--;
 		}
-		__bio_add_page(&bbio->bio, p, eb->len, eb->start - page_offset(p));
-		wbc_account_cgroup_owner(wbc, p, eb->len);
-		unlock_page(p);
+		ret = bio_add_folio(&bbio->bio, folio, eb->len,
+				    eb->start - folio_pos(folio));
+		ASSERT(ret);
+		wbc_account_cgroup_owner(wbc, folio_page(folio, 0), eb->len);
+		folio_unlock(folio);
 	} else {
-		for (int i = 0; i < num_extent_pages(eb); i++) {
-			struct page *p = eb->pages[i];
-
-			lock_page(p);
-			clear_page_dirty_for_io(p);
-			set_page_writeback(p);
-			__bio_add_page(&bbio->bio, p, PAGE_SIZE, 0);
-			wbc_account_cgroup_owner(wbc, p, PAGE_SIZE);
-			wbc->nr_to_write--;
-			unlock_page(p);
+		int num_folios = num_extent_folios(eb);
+
+		for (int i = 0; i < num_folios; i++) {
+			struct folio *folio = eb->folios[i];
+			bool ret;
+
+			folio_lock(folio);
+			folio_clear_dirty_for_io(folio);
+			folio_start_writeback(folio);
+			ret = bio_add_folio(&bbio->bio, folio, folio_size(folio), 0);
+			ASSERT(ret);
+			wbc_account_cgroup_owner(wbc, folio_page(folio, 0),
+						 folio_size(folio));
+			wbc->nr_to_write -= folio_nr_pages(folio);
+			folio_unlock(folio);
 		}
 	}
 	btrfs_submit_bio(bbio, 0);
@@ -1724,7 +1760,8 @@ static noinline_for_stack void write_one_eb(struct extent_buffer *eb,
  */
 static int submit_eb_subpage(struct page *page, struct writeback_control *wbc)
 {
-	struct btrfs_fs_info *fs_info = btrfs_sb(page->mapping->host->i_sb);
+	struct btrfs_fs_info *fs_info = page_to_fs_info(page);
+	struct folio *folio = page_folio(page);
 	int submitted = 0;
 	u64 page_start = page_offset(page);
 	int bit_start = 0;
@@ -1732,7 +1769,7 @@ static int submit_eb_subpage(struct page *page, struct writeback_control *wbc)
 
 	/* Lock and write each dirty extent buffers in the range */
 	while (bit_start < fs_info->subpage_info->bitmap_nr_bits) {
-		struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;
+		struct btrfs_subpage *subpage = folio_get_private(folio);
 		struct extent_buffer *eb;
 		unsigned long flags;
 		u64 start;
@@ -1741,16 +1778,16 @@ static int submit_eb_subpage(struct page *page, struct writeback_control *wbc)
 		 * Take private lock to ensure the subpage won't be detached
 		 * in the meantime.
 		 */
-		spin_lock(&page->mapping->private_lock);
-		if (!PagePrivate(page)) {
-			spin_unlock(&page->mapping->private_lock);
+		spin_lock(&page->mapping->i_private_lock);
+		if (!folio_test_private(folio)) {
+			spin_unlock(&page->mapping->i_private_lock);
 			break;
 		}
 		spin_lock_irqsave(&subpage->lock, flags);
 		if (!test_bit(bit_start + fs_info->subpage_info->dirty_offset,
 			      subpage->bitmaps)) {
 			spin_unlock_irqrestore(&subpage->lock, flags);
-			spin_unlock(&page->mapping->private_lock);
+			spin_unlock(&page->mapping->i_private_lock);
 			bit_start++;
 			continue;
 		}
@@ -1764,7 +1801,7 @@ static int submit_eb_subpage(struct page *page, struct writeback_control *wbc)
 		 */
 		eb = find_extent_buffer_nolock(fs_info, start);
 		spin_unlock_irqrestore(&subpage->lock, flags);
-		spin_unlock(&page->mapping->private_lock);
+		spin_unlock(&page->mapping->i_private_lock);
 
 		/*
 		 * The eb has already reached 0 refs thus find_extent_buffer()
@@ -1807,38 +1844,39 @@ static int submit_eb_page(struct page *page, struct btrfs_eb_write_context *ctx)
 {
 	struct writeback_control *wbc = ctx->wbc;
 	struct address_space *mapping = page->mapping;
+	struct folio *folio = page_folio(page);
 	struct extent_buffer *eb;
 	int ret;
 
-	if (!PagePrivate(page))
+	if (!folio_test_private(folio))
 		return 0;
 
-	if (btrfs_sb(page->mapping->host->i_sb)->nodesize < PAGE_SIZE)
+	if (page_to_fs_info(page)->nodesize < PAGE_SIZE)
 		return submit_eb_subpage(page, wbc);
 
-	spin_lock(&mapping->private_lock);
-	if (!PagePrivate(page)) {
-		spin_unlock(&mapping->private_lock);
+	spin_lock(&mapping->i_private_lock);
+	if (!folio_test_private(folio)) {
+		spin_unlock(&mapping->i_private_lock);
 		return 0;
 	}
 
-	eb = (struct extent_buffer *)page->private;
+	eb = folio_get_private(folio);
 
 	/*
 	 * Shouldn't happen and normally this would be a BUG_ON but no point
 	 * crashing the machine for something we can survive anyway.
 	 */
 	if (WARN_ON(!eb)) {
-		spin_unlock(&mapping->private_lock);
+		spin_unlock(&mapping->i_private_lock);
 		return 0;
 	}
 
 	if (eb == ctx->eb) {
-		spin_unlock(&mapping->private_lock);
+		spin_unlock(&mapping->i_private_lock);
 		return 0;
 	}
 	ret = atomic_inc_not_zero(&eb->refs);
-	spin_unlock(&mapping->private_lock);
+	spin_unlock(&mapping->i_private_lock);
 	if (!ret)
 		return 0;
 
@@ -1871,7 +1909,7 @@ int btree_write_cache_pages(struct address_space *mapping,
 				   struct writeback_control *wbc)
 {
 	struct btrfs_eb_write_context ctx = { .wbc = wbc };
-	struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info;
+	struct btrfs_fs_info *fs_info = inode_to_fs_info(mapping->host);
 	int ret = 0;
 	int done = 0;
 	int nr_to_write_done = 0;
@@ -2159,7 +2197,7 @@ void extent_write_locked_range(struct inode *inode, struct page *locked_page,
 	bool found_error = false;
 	int ret = 0;
 	struct address_space *mapping = inode->i_mapping;
-	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
 	const u32 sectorsize = fs_info->sectorsize;
 	loff_t i_size = i_size_read(inode);
 	u64 cur = start;
@@ -2201,7 +2239,7 @@ void extent_write_locked_range(struct inode *inode, struct page *locked_page,
 						       cur, cur_len, !ret);
 			mapping_set_error(page->mapping, ret);
 		}
-		btrfs_page_unlock_writer(fs_info, page, cur, cur_len);
+		btrfs_folio_unlock_writer(fs_info, page_folio(page), cur, cur_len);
 		if (ret < 0)
 			found_error = true;
 next_page:
@@ -2265,7 +2303,7 @@ int extent_invalidate_folio(struct extent_io_tree *tree,
 	struct extent_state *cached_state = NULL;
 	u64 start = folio_pos(folio);
 	u64 end = start + folio_size(folio) - 1;
-	size_t blocksize = folio->mapping->host->i_sb->s_blocksize;
+	size_t blocksize = folio_to_fs_info(folio)->sectorsize;
 
 	/* This function is only called for the btree inode */
 	ASSERT(tree->owner == IO_TREE_BTREE_INODE_IO);
@@ -2334,7 +2372,7 @@ int try_release_extent_mapping(struct page *page, gfp_t mask)
 	struct extent_map *em;
 	u64 start = page_offset(page);
 	u64 end = start + PAGE_SIZE - 1;
-	struct btrfs_inode *btrfs_inode = BTRFS_I(page->mapping->host);
+	struct btrfs_inode *btrfs_inode = page_to_inode(page);
 	struct extent_io_tree *tree = &btrfs_inode->io_tree;
 	struct extent_map_tree *map = &btrfs_inode->extent_tree;
 
@@ -2352,7 +2390,7 @@ int try_release_extent_mapping(struct page *page, gfp_t mask)
 				write_unlock(&map->lock);
 				break;
 			}
-			if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
+			if ((em->flags & EXTENT_FLAG_PINNED) ||
 			    em->start != start) {
 				write_unlock(&map->lock);
 				free_extent_map(em);
@@ -2369,7 +2407,7 @@ int try_release_extent_mapping(struct page *page, gfp_t mask)
 			 * extra reference on the em.
 			 */
 			if (list_empty(&em->list) ||
-			    test_bit(EXTENT_FLAG_LOGGING, &em->flags))
+			    (em->flags & EXTENT_FLAG_LOGGING))
 				goto remove_em;
 			/*
 			 * If it's in the list of modified extents, remove it
@@ -2409,12 +2447,65 @@ next:
 	return try_release_extent_state(tree, page, mask);
 }
 
+struct btrfs_fiemap_entry {
+	u64 offset;
+	u64 phys;
+	u64 len;
+	u32 flags;
+};
+
+/*
+ * Indicate the caller of emit_fiemap_extent() that it needs to unlock the file
+ * range from the inode's io tree, unlock the subvolume tree search path, flush
+ * the fiemap cache and relock the file range and research the subvolume tree.
+ * The value here is something negative that can't be confused with a valid
+ * errno value and different from 1 because that's also a return value from
+ * fiemap_fill_next_extent() and also it's often used to mean some btree search
+ * did not find a key, so make it some distinct negative value.
+ */
+#define BTRFS_FIEMAP_FLUSH_CACHE (-(MAX_ERRNO + 1))
+
 /*
- * To cache previous fiemap extent
+ * Used to:
  *
- * Will be used for merging fiemap extent
+ * - Cache the next entry to be emitted to the fiemap buffer, so that we can
+ *   merge extents that are contiguous and can be grouped as a single one;
+ *
+ * - Store extents ready to be written to the fiemap buffer in an intermediary
+ *   buffer. This intermediary buffer is to ensure that in case the fiemap
+ *   buffer is memory mapped to the fiemap target file, we don't deadlock
+ *   during btrfs_page_mkwrite(). This is because during fiemap we are locking
+ *   an extent range in order to prevent races with delalloc flushing and
+ *   ordered extent completion, which is needed in order to reliably detect
+ *   delalloc in holes and prealloc extents. And this can lead to a deadlock
+ *   if the fiemap buffer is memory mapped to the file we are running fiemap
+ *   against (a silly, useless in practice scenario, but possible) because
+ *   btrfs_page_mkwrite() will try to lock the same extent range.
  */
 struct fiemap_cache {
+	/* An array of ready fiemap entries. */
+	struct btrfs_fiemap_entry *entries;
+	/* Number of entries in the entries array. */
+	int entries_size;
+	/* Index of the next entry in the entries array to write to. */
+	int entries_pos;
+	/*
+	 * Once the entries array is full, this indicates what's the offset for
+	 * the next file extent item we must search for in the inode's subvolume
+	 * tree after unlocking the extent range in the inode's io tree and
+	 * releasing the search path.
+	 */
+	u64 next_search_offset;
+	/*
+	 * This matches struct fiemap_extent_info::fi_mapped_extents, we use it
+	 * to count ourselves emitted extents and stop instead of relying on
+	 * fiemap_fill_next_extent() because we buffer ready fiemap entries at
+	 * the @entries array, and we want to stop as soon as we hit the max
+	 * amount of extents to map, not just to save time but also to make the
+	 * logic at extent_fiemap() simpler.
+	 */
+	unsigned int extents_mapped;
+	/* Fields for the cached extent (unsubmitted, not ready, extent). */
 	u64 offset;
 	u64 phys;
 	u64 len;
@@ -2422,6 +2513,28 @@ struct fiemap_cache {
 	bool cached;
 };
 
+static int flush_fiemap_cache(struct fiemap_extent_info *fieinfo,
+			      struct fiemap_cache *cache)
+{
+	for (int i = 0; i < cache->entries_pos; i++) {
+		struct btrfs_fiemap_entry *entry = &cache->entries[i];
+		int ret;
+
+		ret = fiemap_fill_next_extent(fieinfo, entry->offset,
+					      entry->phys, entry->len,
+					      entry->flags);
+		/*
+		 * Ignore 1 (reached max entries) because we keep track of that
+		 * ourselves in emit_fiemap_extent().
+		 */
+		if (ret < 0)
+			return ret;
+	}
+	cache->entries_pos = 0;
+
+	return 0;
+}
+
 /*
  * Helper to submit fiemap extent.
  *
@@ -2436,8 +2549,8 @@ static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
 				struct fiemap_cache *cache,
 				u64 offset, u64 phys, u64 len, u32 flags)
 {
+	struct btrfs_fiemap_entry *entry;
 	u64 cache_end;
-	int ret = 0;
 
 	/* Set at the end of extent_fiemap(). */
 	ASSERT((flags & FIEMAP_EXTENT_LAST) == 0);
@@ -2450,7 +2563,9 @@ static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
 	 * find an extent that starts at an offset behind the end offset of the
 	 * previous extent we processed. This happens if fiemap is called
 	 * without FIEMAP_FLAG_SYNC and there are ordered extents completing
-	 * while we call btrfs_next_leaf() (through fiemap_next_leaf_item()).
+	 * after we had to unlock the file range, release the search path, emit
+	 * the fiemap extents stored in the buffer (cache->entries array) and
+	 * the lock the remainder of the range and re-search the btree.
 	 *
 	 * For example we are in leaf X processing its last item, which is the
 	 * file extent item for file range [512K, 1M[, and after
@@ -2563,11 +2678,35 @@ static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
 
 emit:
 	/* Not mergeable, need to submit cached one */
-	ret = fiemap_fill_next_extent(fieinfo, cache->offset, cache->phys,
-				      cache->len, cache->flags);
-	cache->cached = false;
-	if (ret)
-		return ret;
+
+	if (cache->entries_pos == cache->entries_size) {
+		/*
+		 * We will need to research for the end offset of the last
+		 * stored extent and not from the current offset, because after
+		 * unlocking the range and releasing the path, if there's a hole
+		 * between that end offset and this current offset, a new extent
+		 * may have been inserted due to a new write, so we don't want
+		 * to miss it.
+		 */
+		entry = &cache->entries[cache->entries_size - 1];
+		cache->next_search_offset = entry->offset + entry->len;
+		cache->cached = false;
+
+		return BTRFS_FIEMAP_FLUSH_CACHE;
+	}
+
+	entry = &cache->entries[cache->entries_pos];
+	entry->offset = cache->offset;
+	entry->phys = cache->phys;
+	entry->len = cache->len;
+	entry->flags = cache->flags;
+	cache->entries_pos++;
+	cache->extents_mapped++;
+
+	if (cache->extents_mapped == fieinfo->fi_extents_max) {
+		cache->cached = false;
+		return 1;
+	}
 assign:
 	cache->cached = true;
 	cache->offset = offset;
@@ -2693,8 +2832,8 @@ static int fiemap_search_slot(struct btrfs_inode *inode, struct btrfs_path *path
 	 * neighbour leaf).
 	 * We also need the private clone because holding a read lock on an
 	 * extent buffer of the subvolume's b+tree will make lockdep unhappy
-	 * when we call fiemap_fill_next_extent(), because that may cause a page
-	 * fault when filling the user space buffer with fiemap data.
+	 * when we check if extents are shared, as backref walking may need to
+	 * lock the same leaf we are processing.
 	 */
 	clone = btrfs_clone_extent_buffer(path->nodes[0]);
 	if (!clone)
@@ -2734,34 +2873,16 @@ static int fiemap_process_hole(struct btrfs_inode *inode,
 	 * it beyond i_size.
 	 */
 	while (cur_offset < end && cur_offset < i_size) {
-		struct extent_state *cached_state = NULL;
 		u64 delalloc_start;
 		u64 delalloc_end;
 		u64 prealloc_start;
-		u64 lockstart;
-		u64 lockend;
 		u64 prealloc_len = 0;
 		bool delalloc;
 
-		lockstart = round_down(cur_offset, inode->root->fs_info->sectorsize);
-		lockend = round_up(end, inode->root->fs_info->sectorsize);
-
-		/*
-		 * We are only locking for the delalloc range because that's the
-		 * only thing that can change here.  With fiemap we have a lock
-		 * on the inode, so no buffered or direct writes can happen.
-		 *
-		 * However mmaps and normal page writeback will cause this to
-		 * change arbitrarily.  We have to lock the extent lock here to
-		 * make sure that nobody messes with the tree while we're doing
-		 * btrfs_find_delalloc_in_range.
-		 */
-		lock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
 		delalloc = btrfs_find_delalloc_in_range(inode, cur_offset, end,
 							delalloc_cached_state,
 							&delalloc_start,
 							&delalloc_end);
-		unlock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
 		if (!delalloc)
 			break;
 
@@ -2929,6 +3050,7 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
 		  u64 start, u64 len)
 {
 	const u64 ino = btrfs_ino(inode);
+	struct extent_state *cached_state = NULL;
 	struct extent_state *delalloc_cached_state = NULL;
 	struct btrfs_path *path;
 	struct fiemap_cache cache = { 0 };
@@ -2941,18 +3063,23 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
 	bool stopped = false;
 	int ret;
 
+	cache.entries_size = PAGE_SIZE / sizeof(struct btrfs_fiemap_entry);
+	cache.entries = kmalloc_array(cache.entries_size,
+				      sizeof(struct btrfs_fiemap_entry),
+				      GFP_KERNEL);
 	backref_ctx = btrfs_alloc_backref_share_check_ctx();
 	path = btrfs_alloc_path();
-	if (!backref_ctx || !path) {
+	if (!cache.entries || !backref_ctx || !path) {
 		ret = -ENOMEM;
 		goto out;
 	}
 
+restart:
 	range_start = round_down(start, sectorsize);
 	range_end = round_up(start + len, sectorsize);
 	prev_extent_end = range_start;
 
-	btrfs_inode_lock(inode, BTRFS_ILOCK_SHARED);
+	lock_extent(&inode->io_tree, range_start, range_end, &cached_state);
 
 	ret = fiemap_find_last_extent_offset(inode, path, &last_extent_end);
 	if (ret < 0)
@@ -3078,7 +3205,7 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
 		if (ret < 0) {
 			goto out_unlock;
 		} else if (ret > 0) {
-			/* fiemap_fill_next_extent() told us to stop. */
+			/* emit_fiemap_extent() told us to stop. */
 			stopped = true;
 			break;
 		}
@@ -3101,16 +3228,6 @@ next_item:
 	}
 
 check_eof_delalloc:
-	/*
-	 * Release (and free) the path before emitting any final entries to
-	 * fiemap_fill_next_extent() to keep lockdep happy. This is because
-	 * once we find no more file extent items exist, we may have a
-	 * non-cloned leaf, and fiemap_fill_next_extent() can trigger page
-	 * faults when copying data to the user space buffer.
-	 */
-	btrfs_free_path(path);
-	path = NULL;
-
 	if (!stopped && prev_extent_end < range_end) {
 		ret = fiemap_process_hole(inode, fieinfo, &cache,
 					  &delalloc_cached_state, backref_ctx,
@@ -3124,28 +3241,16 @@ check_eof_delalloc:
 		const u64 i_size = i_size_read(&inode->vfs_inode);
 
 		if (prev_extent_end < i_size) {
-			struct extent_state *cached_state = NULL;
 			u64 delalloc_start;
 			u64 delalloc_end;
-			u64 lockstart;
-			u64 lockend;
 			bool delalloc;
 
-			lockstart = round_down(prev_extent_end, sectorsize);
-			lockend = round_up(i_size, sectorsize);
-
-			/*
-			 * See the comment in fiemap_process_hole as to why
-			 * we're doing the locking here.
-			 */
-			lock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
 			delalloc = btrfs_find_delalloc_in_range(inode,
 								prev_extent_end,
 								i_size - 1,
 								&delalloc_cached_state,
 								&delalloc_start,
 								&delalloc_end);
-			unlock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
 			if (!delalloc)
 				cache.flags |= FIEMAP_EXTENT_LAST;
 		} else {
@@ -3153,12 +3258,39 @@ check_eof_delalloc:
 		}
 	}
 
-	ret = emit_last_fiemap_cache(fieinfo, &cache);
-
 out_unlock:
-	btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
+	unlock_extent(&inode->io_tree, range_start, range_end, &cached_state);
+
+	if (ret == BTRFS_FIEMAP_FLUSH_CACHE) {
+		btrfs_release_path(path);
+		ret = flush_fiemap_cache(fieinfo, &cache);
+		if (ret)
+			goto out;
+		len -= cache.next_search_offset - start;
+		start = cache.next_search_offset;
+		goto restart;
+	} else if (ret < 0) {
+		goto out;
+	}
+
+	/*
+	 * Must free the path before emitting to the fiemap buffer because we
+	 * may have a non-cloned leaf and if the fiemap buffer is memory mapped
+	 * to a file, a write into it (through btrfs_page_mkwrite()) may trigger
+	 * waiting for an ordered extent that in order to complete needs to
+	 * modify that leaf, therefore leading to a deadlock.
+	 */
+	btrfs_free_path(path);
+	path = NULL;
+
+	ret = flush_fiemap_cache(fieinfo, &cache);
+	if (ret)
+		goto out;
+
+	ret = emit_last_fiemap_cache(fieinfo, &cache);
 out:
 	free_extent_state(delalloc_cached_state);
+	kfree(cache.entries);
 	btrfs_free_backref_share_ctx(backref_ctx);
 	btrfs_free_path(path);
 	return ret;
@@ -3175,14 +3307,14 @@ static int extent_buffer_under_io(const struct extent_buffer *eb)
 		test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
 }
 
-static bool page_range_has_eb(struct btrfs_fs_info *fs_info, struct page *page)
+static bool folio_range_has_eb(struct btrfs_fs_info *fs_info, struct folio *folio)
 {
 	struct btrfs_subpage *subpage;
 
-	lockdep_assert_held(&page->mapping->private_lock);
+	lockdep_assert_held(&folio->mapping->i_private_lock);
 
-	if (PagePrivate(page)) {
-		subpage = (struct btrfs_subpage *)page->private;
+	if (folio_test_private(folio)) {
+		subpage = folio_get_private(folio);
 		if (atomic_read(&subpage->eb_refs))
 			return true;
 		/*
@@ -3195,21 +3327,21 @@ static bool page_range_has_eb(struct btrfs_fs_info *fs_info, struct page *page)
 	return false;
 }
 
-static void detach_extent_buffer_page(struct extent_buffer *eb, struct page *page)
+static void detach_extent_buffer_folio(struct extent_buffer *eb, struct folio *folio)
 {
 	struct btrfs_fs_info *fs_info = eb->fs_info;
 	const bool mapped = !test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags);
 
 	/*
-	 * For mapped eb, we're going to change the page private, which should
-	 * be done under the private_lock.
+	 * For mapped eb, we're going to change the folio private, which should
+	 * be done under the i_private_lock.
 	 */
 	if (mapped)
-		spin_lock(&page->mapping->private_lock);
+		spin_lock(&folio->mapping->i_private_lock);
 
-	if (!PagePrivate(page)) {
+	if (!folio_test_private(folio)) {
 		if (mapped)
-			spin_unlock(&page->mapping->private_lock);
+			spin_unlock(&folio->mapping->i_private_lock);
 		return;
 	}
 
@@ -3218,66 +3350,58 @@ static void detach_extent_buffer_page(struct extent_buffer *eb, struct page *pag
 		 * We do this since we'll remove the pages after we've
 		 * removed the eb from the radix tree, so we could race
 		 * and have this page now attached to the new eb.  So
-		 * only clear page_private if it's still connected to
+		 * only clear folio if it's still connected to
 		 * this eb.
 		 */
-		if (PagePrivate(page) &&
-		    page->private == (unsigned long)eb) {
+		if (folio_test_private(folio) && folio_get_private(folio) == eb) {
 			BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
-			BUG_ON(PageDirty(page));
-			BUG_ON(PageWriteback(page));
-			/*
-			 * We need to make sure we haven't be attached
-			 * to a new eb.
-			 */
-			detach_page_private(page);
+			BUG_ON(folio_test_dirty(folio));
+			BUG_ON(folio_test_writeback(folio));
+			/* We need to make sure we haven't be attached to a new eb. */
+			folio_detach_private(folio);
 		}
 		if (mapped)
-			spin_unlock(&page->mapping->private_lock);
+			spin_unlock(&folio->mapping->i_private_lock);
 		return;
 	}
 
 	/*
-	 * For subpage, we can have dummy eb with page private.  In this case,
-	 * we can directly detach the private as such page is only attached to
-	 * one dummy eb, no sharing.
+	 * For subpage, we can have dummy eb with folio private attached.  In
+	 * this case, we can directly detach the private as such folio is only
+	 * attached to one dummy eb, no sharing.
 	 */
 	if (!mapped) {
-		btrfs_detach_subpage(fs_info, page);
+		btrfs_detach_subpage(fs_info, folio);
 		return;
 	}
 
-	btrfs_page_dec_eb_refs(fs_info, page);
+	btrfs_folio_dec_eb_refs(fs_info, folio);
 
 	/*
-	 * We can only detach the page private if there are no other ebs in the
+	 * We can only detach the folio private if there are no other ebs in the
 	 * page range and no unfinished IO.
 	 */
-	if (!page_range_has_eb(fs_info, page))
-		btrfs_detach_subpage(fs_info, page);
+	if (!folio_range_has_eb(fs_info, folio))
+		btrfs_detach_subpage(fs_info, folio);
 
-	spin_unlock(&page->mapping->private_lock);
+	spin_unlock(&folio->mapping->i_private_lock);
 }
 
 /* Release all pages attached to the extent buffer */
 static void btrfs_release_extent_buffer_pages(struct extent_buffer *eb)
 {
-	int i;
-	int num_pages;
-
 	ASSERT(!extent_buffer_under_io(eb));
 
-	num_pages = num_extent_pages(eb);
-	for (i = 0; i < num_pages; i++) {
-		struct page *page = eb->pages[i];
+	for (int i = 0; i < INLINE_EXTENT_BUFFER_PAGES; i++) {
+		struct folio *folio = eb->folios[i];
 
-		if (!page)
+		if (!folio)
 			continue;
 
-		detach_extent_buffer_page(eb, page);
+		detach_extent_buffer_folio(eb, folio);
 
-		/* One for when we allocated the page */
-		put_page(page);
+		/* One for when we allocated the folio. */
+		folio_put(folio);
 	}
 }
 
@@ -3315,9 +3439,8 @@ __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
 
 struct extent_buffer *btrfs_clone_extent_buffer(const struct extent_buffer *src)
 {
-	int i;
 	struct extent_buffer *new;
-	int num_pages = num_extent_pages(src);
+	int num_folios = num_extent_folios(src);
 	int ret;
 
 	new = __alloc_extent_buffer(src->fs_info, src->start, src->len);
@@ -3331,22 +3454,22 @@ struct extent_buffer *btrfs_clone_extent_buffer(const struct extent_buffer *src)
 	 */
 	set_bit(EXTENT_BUFFER_UNMAPPED, &new->bflags);
 
-	ret = btrfs_alloc_page_array(num_pages, new->pages);
+	ret = alloc_eb_folio_array(new, 0);
 	if (ret) {
 		btrfs_release_extent_buffer(new);
 		return NULL;
 	}
 
-	for (i = 0; i < num_pages; i++) {
+	for (int i = 0; i < num_folios; i++) {
+		struct folio *folio = new->folios[i];
 		int ret;
-		struct page *p = new->pages[i];
 
-		ret = attach_extent_buffer_page(new, p, NULL);
+		ret = attach_extent_buffer_folio(new, folio, NULL);
 		if (ret < 0) {
 			btrfs_release_extent_buffer(new);
 			return NULL;
 		}
-		WARN_ON(PageDirty(p));
+		WARN_ON(folio_test_dirty(folio));
 	}
 	copy_extent_buffer_full(new, src);
 	set_extent_buffer_uptodate(new);
@@ -3358,23 +3481,20 @@ struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
 						  u64 start, unsigned long len)
 {
 	struct extent_buffer *eb;
-	int num_pages;
-	int i;
+	int num_folios = 0;
 	int ret;
 
 	eb = __alloc_extent_buffer(fs_info, start, len);
 	if (!eb)
 		return NULL;
 
-	num_pages = num_extent_pages(eb);
-	ret = btrfs_alloc_page_array(num_pages, eb->pages);
+	ret = alloc_eb_folio_array(eb, 0);
 	if (ret)
 		goto err;
 
-	for (i = 0; i < num_pages; i++) {
-		struct page *p = eb->pages[i];
-
-		ret = attach_extent_buffer_page(eb, p, NULL);
+	num_folios = num_extent_folios(eb);
+	for (int i = 0; i < num_folios; i++) {
+		ret = attach_extent_buffer_folio(eb, eb->folios[i], NULL);
 		if (ret < 0)
 			goto err;
 	}
@@ -3385,10 +3505,10 @@ struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
 
 	return eb;
 err:
-	for (i = 0; i < num_pages; i++) {
-		if (eb->pages[i]) {
-			detach_extent_buffer_page(eb, eb->pages[i]);
-			__free_page(eb->pages[i]);
+	for (int i = 0; i < num_folios; i++) {
+		if (eb->folios[i]) {
+			detach_extent_buffer_folio(eb, eb->folios[i]);
+			__folio_put(eb->folios[i]);
 		}
 	}
 	__free_extent_buffer(eb);
@@ -3437,20 +3557,14 @@ static void check_buffer_tree_ref(struct extent_buffer *eb)
 	spin_unlock(&eb->refs_lock);
 }
 
-static void mark_extent_buffer_accessed(struct extent_buffer *eb,
-		struct page *accessed)
+static void mark_extent_buffer_accessed(struct extent_buffer *eb)
 {
-	int num_pages, i;
+	int num_folios= num_extent_folios(eb);
 
 	check_buffer_tree_ref(eb);
 
-	num_pages = num_extent_pages(eb);
-	for (i = 0; i < num_pages; i++) {
-		struct page *p = eb->pages[i];
-
-		if (p != accessed)
-			mark_page_accessed(p);
-	}
+	for (int i = 0; i < num_folios; i++)
+		folio_mark_accessed(eb->folios[i]);
 }
 
 struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
@@ -3478,7 +3592,7 @@ struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
 		spin_lock(&eb->refs_lock);
 		spin_unlock(&eb->refs_lock);
 	}
-	mark_extent_buffer_accessed(eb, NULL);
+	mark_extent_buffer_accessed(eb);
 	return eb;
 }
 
@@ -3527,6 +3641,7 @@ free_eb:
 static struct extent_buffer *grab_extent_buffer(
 		struct btrfs_fs_info *fs_info, struct page *page)
 {
+	struct folio *folio = page_folio(page);
 	struct extent_buffer *exists;
 
 	/*
@@ -3538,21 +3653,21 @@ static struct extent_buffer *grab_extent_buffer(
 		return NULL;
 
 	/* Page not yet attached to an extent buffer */
-	if (!PagePrivate(page))
+	if (!folio_test_private(folio))
 		return NULL;
 
 	/*
 	 * We could have already allocated an eb for this page and attached one
 	 * so lets see if we can get a ref on the existing eb, and if we can we
 	 * know it's good and we can just return that one, else we know we can
-	 * just overwrite page->private.
+	 * just overwrite folio private.
 	 */
-	exists = (struct extent_buffer *)page->private;
+	exists = folio_get_private(folio);
 	if (atomic_inc_not_zero(&exists->refs))
 		return exists;
 
 	WARN_ON(PageDirty(page));
-	detach_page_private(page);
+	folio_detach_private(folio);
 	return NULL;
 }
 
@@ -3586,19 +3701,88 @@ static int check_eb_alignment(struct btrfs_fs_info *fs_info, u64 start)
 	return 0;
 }
 
+
+/*
+ * Return 0 if eb->folios[i] is attached to btree inode successfully.
+ * Return >0 if there is already another extent buffer for the range,
+ * and @found_eb_ret would be updated.
+ * Return -EAGAIN if the filemap has an existing folio but with different size
+ * than @eb.
+ * The caller needs to free the existing folios and retry using the same order.
+ */
+static int attach_eb_folio_to_filemap(struct extent_buffer *eb, int i,
+				      struct extent_buffer **found_eb_ret)
+{
+
+	struct btrfs_fs_info *fs_info = eb->fs_info;
+	struct address_space *mapping = fs_info->btree_inode->i_mapping;
+	const unsigned long index = eb->start >> PAGE_SHIFT;
+	struct folio *existing_folio;
+	int ret;
+
+	ASSERT(found_eb_ret);
+
+	/* Caller should ensure the folio exists. */
+	ASSERT(eb->folios[i]);
+
+retry:
+	ret = filemap_add_folio(mapping, eb->folios[i], index + i,
+				GFP_NOFS | __GFP_NOFAIL);
+	if (!ret)
+		return 0;
+
+	existing_folio = filemap_lock_folio(mapping, index + i);
+	/* The page cache only exists for a very short time, just retry. */
+	if (IS_ERR(existing_folio))
+		goto retry;
+
+	/* For now, we should only have single-page folios for btree inode. */
+	ASSERT(folio_nr_pages(existing_folio) == 1);
+
+	if (folio_size(existing_folio) != folio_size(eb->folios[0])) {
+		folio_unlock(existing_folio);
+		folio_put(existing_folio);
+		return -EAGAIN;
+	}
+
+	if (fs_info->nodesize < PAGE_SIZE) {
+		/*
+		 * We're going to reuse the existing page, can drop our page
+		 * and subpage structure now.
+		 */
+		__free_page(folio_page(eb->folios[i], 0));
+		eb->folios[i] = existing_folio;
+	} else {
+		struct extent_buffer *existing_eb;
+
+		existing_eb = grab_extent_buffer(fs_info,
+						 folio_page(existing_folio, 0));
+		if (existing_eb) {
+			/* The extent buffer still exists, we can use it directly. */
+			*found_eb_ret = existing_eb;
+			folio_unlock(existing_folio);
+			folio_put(existing_folio);
+			return 1;
+		}
+		/* The extent buffer no longer exists, we can reuse the folio. */
+		__free_page(folio_page(eb->folios[i], 0));
+		eb->folios[i] = existing_folio;
+	}
+	return 0;
+}
+
 struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
 					  u64 start, u64 owner_root, int level)
 {
 	unsigned long len = fs_info->nodesize;
-	int num_pages;
-	int i;
-	unsigned long index = start >> PAGE_SHIFT;
+	int num_folios;
+	int attached = 0;
 	struct extent_buffer *eb;
-	struct extent_buffer *exists = NULL;
-	struct page *p;
+	struct extent_buffer *existing_eb = NULL;
 	struct address_space *mapping = fs_info->btree_inode->i_mapping;
 	struct btrfs_subpage *prealloc = NULL;
 	u64 lockdep_owner = owner_root;
+	bool page_contig = true;
 	int uptodate = 1;
 	int ret;
 
@@ -3633,11 +3817,9 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
 
 	btrfs_set_buffer_lockdep_class(lockdep_owner, eb, level);
 
-	num_pages = num_extent_pages(eb);
-
 	/*
-	 * Preallocate page->private for subpage case, so that we won't
-	 * allocate memory with private_lock nor page lock hold.
+	 * Preallocate folio private for subpage case, so that we won't
+	 * allocate memory with i_private_lock nor page lock hold.
 	 *
 	 * The memory will be freed by attach_extent_buffer_page() or freed
 	 * manually if we exit earlier.
@@ -3645,47 +3827,89 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
 	if (fs_info->nodesize < PAGE_SIZE) {
 		prealloc = btrfs_alloc_subpage(fs_info, BTRFS_SUBPAGE_METADATA);
 		if (IS_ERR(prealloc)) {
-			exists = ERR_CAST(prealloc);
-			goto free_eb;
+			ret = PTR_ERR(prealloc);
+			goto out;
 		}
 	}
 
-	for (i = 0; i < num_pages; i++, index++) {
-		p = find_or_create_page(mapping, index, GFP_NOFS|__GFP_NOFAIL);
-		if (!p) {
-			exists = ERR_PTR(-ENOMEM);
-			btrfs_free_subpage(prealloc);
-			goto free_eb;
+reallocate:
+	/* Allocate all pages first. */
+	ret = alloc_eb_folio_array(eb, __GFP_NOFAIL);
+	if (ret < 0) {
+		btrfs_free_subpage(prealloc);
+		goto out;
+	}
+
+	num_folios = num_extent_folios(eb);
+	/* Attach all pages to the filemap. */
+	for (int i = 0; i < num_folios; i++) {
+		struct folio *folio;
+
+		ret = attach_eb_folio_to_filemap(eb, i, &existing_eb);
+		if (ret > 0) {
+			ASSERT(existing_eb);
+			goto out;
 		}
 
-		spin_lock(&mapping->private_lock);
-		exists = grab_extent_buffer(fs_info, p);
-		if (exists) {
-			spin_unlock(&mapping->private_lock);
-			unlock_page(p);
-			put_page(p);
-			mark_extent_buffer_accessed(exists, p);
-			btrfs_free_subpage(prealloc);
-			goto free_eb;
+		/*
+		 * TODO: Special handling for a corner case where the order of
+		 * folios mismatch between the new eb and filemap.
+		 *
+		 * This happens when:
+		 *
+		 * - the new eb is using higher order folio
+		 *
+		 * - the filemap is still using 0-order folios for the range
+		 *   This can happen at the previous eb allocation, and we don't
+		 *   have higher order folio for the call.
+		 *
+		 * - the existing eb has already been freed
+		 *
+		 * In this case, we have to free the existing folios first, and
+		 * re-allocate using the same order.
+		 * Thankfully this is not going to happen yet, as we're still
+		 * using 0-order folios.
+		 */
+		if (unlikely(ret == -EAGAIN)) {
+			ASSERT(0);
+			goto reallocate;
 		}
+		attached++;
+
+		/*
+		 * Only after attach_eb_folio_to_filemap(), eb->folios[] is
+		 * reliable, as we may choose to reuse the existing page cache
+		 * and free the allocated page.
+		 */
+		folio = eb->folios[i];
+		spin_lock(&mapping->i_private_lock);
 		/* Should not fail, as we have preallocated the memory */
-		ret = attach_extent_buffer_page(eb, p, prealloc);
+		ret = attach_extent_buffer_folio(eb, folio, prealloc);
 		ASSERT(!ret);
 		/*
 		 * To inform we have extra eb under allocation, so that
-		 * detach_extent_buffer_page() won't release the page private
+		 * detach_extent_buffer_page() won't release the folio private
 		 * when the eb hasn't yet been inserted into radix tree.
 		 *
 		 * The ref will be decreased when the eb released the page, in
 		 * detach_extent_buffer_page().
 		 * Thus needs no special handling in error path.
 		 */
-		btrfs_page_inc_eb_refs(fs_info, p);
-		spin_unlock(&mapping->private_lock);
+		btrfs_folio_inc_eb_refs(fs_info, folio);
+		spin_unlock(&mapping->i_private_lock);
+
+		WARN_ON(btrfs_folio_test_dirty(fs_info, folio, eb->start, eb->len));
+
+		/*
+		 * Check if the current page is physically contiguous with previous eb
+		 * page.
+		 * At this stage, either we allocated a large folio, thus @i
+		 * would only be 0, or we fall back to per-page allocation.
+		 */
+		if (i && folio_page(eb->folios[i - 1], 0) + 1 != folio_page(folio, 0))
+			page_contig = false;
 
-		WARN_ON(btrfs_page_test_dirty(fs_info, p, eb->start, eb->len));
-		eb->pages[i] = p;
-		if (!btrfs_page_test_uptodate(fs_info, p, eb->start, eb->len))
+		if (!btrfs_folio_test_uptodate(fs_info, folio, eb->start, eb->len))
 			uptodate = 0;
 
 		/*
@@ -3698,12 +3922,13 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
 	}
 	if (uptodate)
 		set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
+	/* All pages are physically contiguous, can skip cross page handling. */
+	if (page_contig)
+		eb->addr = folio_address(eb->folios[0]) + offset_in_page(eb->start);
 again:
 	ret = radix_tree_preload(GFP_NOFS);
-	if (ret) {
-		exists = ERR_PTR(ret);
-		goto free_eb;
-	}
+	if (ret)
+		goto out;
 
 	spin_lock(&fs_info->buffer_lock);
 	ret = radix_tree_insert(&fs_info->buffer_radix,
@@ -3711,9 +3936,10 @@ again:
 	spin_unlock(&fs_info->buffer_lock);
 	radix_tree_preload_end();
 	if (ret == -EEXIST) {
-		exists = find_extent_buffer(fs_info, start);
-		if (exists)
-			goto free_eb;
+		ret = 0;
+		existing_eb = find_extent_buffer(fs_info, start);
+		if (existing_eb)
+			goto out;
 		else
 			goto again;
 	}
@@ -3726,19 +3952,46 @@ again:
 	 * btree_release_folio will correctly detect that a page belongs to a
 	 * live buffer and won't free them prematurely.
 	 */
-	for (i = 0; i < num_pages; i++)
-		unlock_page(eb->pages[i]);
+	for (int i = 0; i < num_folios; i++)
+		unlock_page(folio_page(eb->folios[i], 0));
 	return eb;
 
-free_eb:
+out:
 	WARN_ON(!atomic_dec_and_test(&eb->refs));
-	for (i = 0; i < num_pages; i++) {
-		if (eb->pages[i])
-			unlock_page(eb->pages[i]);
+
+	/*
+	 * Any attached folios need to be detached before we unlock them.  This
+	 * is because when we're inserting our new folios into the mapping, and
+	 * then attaching our eb to that folio.  If we fail to insert our folio
+	 * we'll lookup the folio for that index, and grab that EB.  We do not
+	 * want that to grab this eb, as we're getting ready to free it.  So we
+	 * have to detach it first and then unlock it.
+	 *
+	 * We have to drop our reference and NULL it out here because in the
+	 * subpage case detaching does a btrfs_folio_dec_eb_refs() for our eb.
+	 * Below when we call btrfs_release_extent_buffer() we will call
+	 * detach_extent_buffer_folio() on our remaining pages in the !subpage
+	 * case.  If we left eb->folios[i] populated in the subpage case we'd
+	 * double put our reference and be super sad.
+	 */
+	for (int i = 0; i < attached; i++) {
+		ASSERT(eb->folios[i]);
+		detach_extent_buffer_folio(eb, eb->folios[i]);
+		unlock_page(folio_page(eb->folios[i], 0));
+		folio_put(eb->folios[i]);
+		eb->folios[i] = NULL;
 	}
+	/*
+	 * Now all pages of that extent buffer is unmapped, set UNMAPPED flag,
+	 * so it can be cleaned up without utlizing page->mapping.
+	 */
+	set_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags);
 
 	btrfs_release_extent_buffer(eb);
-	return exists;
+	if (ret < 0)
+		return ERR_PTR(ret);
+	ASSERT(existing_eb);
+	return existing_eb;
 }
 
 static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
@@ -3830,31 +4083,30 @@ void free_extent_buffer_stale(struct extent_buffer *eb)
 	release_extent_buffer(eb);
 }
 
-static void btree_clear_page_dirty(struct page *page)
+static void btree_clear_folio_dirty(struct folio *folio)
 {
-	ASSERT(PageDirty(page));
-	ASSERT(PageLocked(page));
-	clear_page_dirty_for_io(page);
-	xa_lock_irq(&page->mapping->i_pages);
-	if (!PageDirty(page))
-		__xa_clear_mark(&page->mapping->i_pages,
-				page_index(page), PAGECACHE_TAG_DIRTY);
-	xa_unlock_irq(&page->mapping->i_pages);
+	ASSERT(folio_test_dirty(folio));
+	ASSERT(folio_test_locked(folio));
+	folio_clear_dirty_for_io(folio);
+	xa_lock_irq(&folio->mapping->i_pages);
+	if (!folio_test_dirty(folio))
+		__xa_clear_mark(&folio->mapping->i_pages,
+				folio_index(folio), PAGECACHE_TAG_DIRTY);
+	xa_unlock_irq(&folio->mapping->i_pages);
 }
 
 static void clear_subpage_extent_buffer_dirty(const struct extent_buffer *eb)
 {
 	struct btrfs_fs_info *fs_info = eb->fs_info;
-	struct page *page = eb->pages[0];
+	struct folio *folio = eb->folios[0];
 	bool last;
 
-	/* btree_clear_page_dirty() needs page locked */
-	lock_page(page);
-	last = btrfs_subpage_clear_and_test_dirty(fs_info, page, eb->start,
-						  eb->len);
+	/* btree_clear_folio_dirty() needs page locked. */
+	folio_lock(folio);
+	last = btrfs_subpage_clear_and_test_dirty(fs_info, folio, eb->start, eb->len);
 	if (last)
-		btree_clear_page_dirty(page);
-	unlock_page(page);
+		btree_clear_folio_dirty(folio);
+	folio_unlock(folio);
 	WARN_ON(atomic_read(&eb->refs) == 0);
 }
 
@@ -3862,15 +4114,27 @@ void btrfs_clear_buffer_dirty(struct btrfs_trans_handle *trans,
 			      struct extent_buffer *eb)
 {
 	struct btrfs_fs_info *fs_info = eb->fs_info;
-	int i;
-	int num_pages;
-	struct page *page;
+	int num_folios;
 
 	btrfs_assert_tree_write_locked(eb);
 
 	if (trans && btrfs_header_generation(eb) != trans->transid)
 		return;
 
+	/*
+	 * Instead of clearing the dirty flag off of the buffer, mark it as
+	 * EXTENT_BUFFER_ZONED_ZEROOUT. This allows us to preserve
+	 * write-ordering in zoned mode, without the need to later re-dirty
+	 * the extent_buffer.
+	 *
+	 * The actual zeroout of the buffer will happen later in
+	 * btree_csum_one_bio.
+	 */
+	if (btrfs_is_zoned(fs_info) && test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
+		set_bit(EXTENT_BUFFER_ZONED_ZEROOUT, &eb->bflags);
+		return;
+	}
+
 	if (!test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags))
 		return;
 
@@ -3880,30 +4144,29 @@ void btrfs_clear_buffer_dirty(struct btrfs_trans_handle *trans,
 	if (eb->fs_info->nodesize < PAGE_SIZE)
 		return clear_subpage_extent_buffer_dirty(eb);
 
-	num_pages = num_extent_pages(eb);
+	num_folios = num_extent_folios(eb);
+	for (int i = 0; i < num_folios; i++) {
+		struct folio *folio = eb->folios[i];
 
-	for (i = 0; i < num_pages; i++) {
-		page = eb->pages[i];
-		if (!PageDirty(page))
+		if (!folio_test_dirty(folio))
 			continue;
-		lock_page(page);
-		btree_clear_page_dirty(page);
-		unlock_page(page);
+		folio_lock(folio);
+		btree_clear_folio_dirty(folio);
+		folio_unlock(folio);
 	}
 	WARN_ON(atomic_read(&eb->refs) == 0);
 }
 
 void set_extent_buffer_dirty(struct extent_buffer *eb)
 {
-	int i;
-	int num_pages;
+	int num_folios;
 	bool was_dirty;
 
 	check_buffer_tree_ref(eb);
 
 	was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
 
-	num_pages = num_extent_pages(eb);
+	num_folios = num_extent_folios(eb);
 	WARN_ON(atomic_read(&eb->refs) == 0);
 	WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
 
@@ -3922,34 +4185,32 @@ void set_extent_buffer_dirty(struct extent_buffer *eb)
 		 * the above race.
 		 */
 		if (subpage)
-			lock_page(eb->pages[0]);
-		for (i = 0; i < num_pages; i++)
-			btrfs_page_set_dirty(eb->fs_info, eb->pages[i],
-					     eb->start, eb->len);
+			lock_page(folio_page(eb->folios[0], 0));
+		for (int i = 0; i < num_folios; i++)
+			btrfs_folio_set_dirty(eb->fs_info, eb->folios[i],
+					      eb->start, eb->len);
 		if (subpage)
-			unlock_page(eb->pages[0]);
+			unlock_page(folio_page(eb->folios[0], 0));
 		percpu_counter_add_batch(&eb->fs_info->dirty_metadata_bytes,
 					 eb->len,
 					 eb->fs_info->dirty_metadata_batch);
 	}
 #ifdef CONFIG_BTRFS_DEBUG
-	for (i = 0; i < num_pages; i++)
-		ASSERT(PageDirty(eb->pages[i]));
+	for (int i = 0; i < num_folios; i++)
+		ASSERT(folio_test_dirty(eb->folios[i]));
 #endif
 }
 
 void clear_extent_buffer_uptodate(struct extent_buffer *eb)
 {
 	struct btrfs_fs_info *fs_info = eb->fs_info;
-	struct page *page;
-	int num_pages;
-	int i;
+	int num_folios = num_extent_folios(eb);
 
 	clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
-	num_pages = num_extent_pages(eb);
-	for (i = 0; i < num_pages; i++) {
-		page = eb->pages[i];
-		if (!page)
+	for (int i = 0; i < num_folios; i++) {
+		struct folio *folio = eb->folios[i];
+
+		if (!folio)
 			continue;
 
 		/*
@@ -3957,44 +4218,40 @@ void clear_extent_buffer_uptodate(struct extent_buffer *eb)
 		 * btrfs_is_subpage() can not handle cloned/dummy metadata.
 		 */
 		if (fs_info->nodesize >= PAGE_SIZE)
-			ClearPageUptodate(page);
+			folio_clear_uptodate(folio);
 		else
-			btrfs_subpage_clear_uptodate(fs_info, page, eb->start,
-						     eb->len);
+			btrfs_subpage_clear_uptodate(fs_info, folio,
+						     eb->start, eb->len);
 	}
 }
 
 void set_extent_buffer_uptodate(struct extent_buffer *eb)
 {
 	struct btrfs_fs_info *fs_info = eb->fs_info;
-	struct page *page;
-	int num_pages;
-	int i;
+	int num_folios = num_extent_folios(eb);
 
 	set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
-	num_pages = num_extent_pages(eb);
-	for (i = 0; i < num_pages; i++) {
-		page = eb->pages[i];
+	for (int i = 0; i < num_folios; i++) {
+		struct folio *folio = eb->folios[i];
 
 		/*
 		 * This is special handling for metadata subpage, as regular
 		 * btrfs_is_subpage() can not handle cloned/dummy metadata.
 		 */
 		if (fs_info->nodesize >= PAGE_SIZE)
-			SetPageUptodate(page);
+			folio_mark_uptodate(folio);
 		else
-			btrfs_subpage_set_uptodate(fs_info, page, eb->start,
-						   eb->len);
+			btrfs_subpage_set_uptodate(fs_info, folio,
+						   eb->start, eb->len);
 	}
 }
 
-static void extent_buffer_read_end_io(struct btrfs_bio *bbio)
+static void end_bbio_meta_read(struct btrfs_bio *bbio)
 {
 	struct extent_buffer *eb = bbio->private;
 	struct btrfs_fs_info *fs_info = eb->fs_info;
 	bool uptodate = !bbio->bio.bi_status;
-	struct bvec_iter_all iter_all;
-	struct bio_vec *bvec;
+	struct folio_iter fi;
 	u32 bio_offset = 0;
 
 	eb->read_mirror = bbio->mirror_num;
@@ -4010,15 +4267,15 @@ static void extent_buffer_read_end_io(struct btrfs_bio *bbio)
 		set_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
 	}
 
-	bio_for_each_segment_all(bvec, &bbio->bio, iter_all) {
+	bio_for_each_folio_all(fi, &bbio->bio) {
+		struct folio *folio = fi.folio;
 		u64 start = eb->start + bio_offset;
-		struct page *page = bvec->bv_page;
-		u32 len = bvec->bv_len;
+		u32 len = fi.length;
 
 		if (uptodate)
-			btrfs_page_set_uptodate(fs_info, page, start, len);
+			btrfs_folio_set_uptodate(fs_info, folio, start, len);
 		else
-			btrfs_page_clear_uptodate(fs_info, page, start, len);
+			btrfs_folio_clear_uptodate(fs_info, folio, start, len);
 
 		bio_offset += len;
 	}
@@ -4034,8 +4291,8 @@ static void extent_buffer_read_end_io(struct btrfs_bio *bbio)
 int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num,
 			     struct btrfs_tree_parent_check *check)
 {
-	int num_pages = num_extent_pages(eb), i;
 	struct btrfs_bio *bbio;
+	bool ret;
 
 	if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
 		return 0;
@@ -4072,17 +4329,24 @@ int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num,
 
 	bbio = btrfs_bio_alloc(INLINE_EXTENT_BUFFER_PAGES,
 			       REQ_OP_READ | REQ_META, eb->fs_info,
-			       extent_buffer_read_end_io, eb);
+			       end_bbio_meta_read, eb);
 	bbio->bio.bi_iter.bi_sector = eb->start >> SECTOR_SHIFT;
 	bbio->inode = BTRFS_I(eb->fs_info->btree_inode);
 	bbio->file_offset = eb->start;
 	memcpy(&bbio->parent_check, check, sizeof(*check));
 	if (eb->fs_info->nodesize < PAGE_SIZE) {
-		__bio_add_page(&bbio->bio, eb->pages[0], eb->len,
-			       eb->start - page_offset(eb->pages[0]));
+		ret = bio_add_folio(&bbio->bio, eb->folios[0], eb->len,
+				    eb->start - folio_pos(eb->folios[0]));
+		ASSERT(ret);
 	} else {
-		for (i = 0; i < num_pages; i++)
-			__bio_add_page(&bbio->bio, eb->pages[i], PAGE_SIZE, 0);
+		int num_folios = num_extent_folios(eb);
+
+		for (int i = 0; i < num_folios; i++) {
+			struct folio *folio = eb->folios[i];
+
+			ret = bio_add_folio(&bbio->bio, folio, folio_size(folio), 0);
+			ASSERT(ret);
+		}
 	}
 	btrfs_submit_bio(bbio, mirror_num);
 
@@ -4129,29 +4393,33 @@ static inline int check_eb_range(const struct extent_buffer *eb,
 void read_extent_buffer(const struct extent_buffer *eb, void *dstv,
 			unsigned long start, unsigned long len)
 {
+	const int unit_size = folio_size(eb->folios[0]);
 	size_t cur;
 	size_t offset;
-	struct page *page;
-	char *kaddr;
 	char *dst = (char *)dstv;
-	unsigned long i = get_eb_page_index(start);
+	unsigned long i = get_eb_folio_index(eb, start);
 
 	if (check_eb_range(eb, start, len)) {
 		/*
 		 * Invalid range hit, reset the memory, so callers won't get
-		 * some random garbage for their uninitialzed memory.
+		 * some random garbage for their uninitialized memory.
 		 */
 		memset(dstv, 0, len);
 		return;
 	}
 
-	offset = get_eb_offset_in_page(eb, start);
+	if (eb->addr) {
+		memcpy(dstv, eb->addr + start, len);
+		return;
+	}
+
+	offset = get_eb_offset_in_folio(eb, start);
 
 	while (len > 0) {
-		page = eb->pages[i];
+		char *kaddr;
 
-		cur = min(len, (PAGE_SIZE - offset));
-		kaddr = page_address(page);
+		cur = min(len, unit_size - offset);
+		kaddr = folio_address(eb->folios[i]);
 		memcpy(dst, kaddr + offset, cur);
 
 		dst += cur;
@@ -4165,24 +4433,29 @@ int read_extent_buffer_to_user_nofault(const struct extent_buffer *eb,
 				       void __user *dstv,
 				       unsigned long start, unsigned long len)
 {
+	const int unit_size = folio_size(eb->folios[0]);
 	size_t cur;
 	size_t offset;
-	struct page *page;
-	char *kaddr;
 	char __user *dst = (char __user *)dstv;
-	unsigned long i = get_eb_page_index(start);
+	unsigned long i = get_eb_folio_index(eb, start);
 	int ret = 0;
 
 	WARN_ON(start > eb->len);
 	WARN_ON(start + len > eb->start + eb->len);
 
-	offset = get_eb_offset_in_page(eb, start);
+	if (eb->addr) {
+		if (copy_to_user_nofault(dstv, eb->addr + start, len))
+			ret = -EFAULT;
+		return ret;
+	}
+
+	offset = get_eb_offset_in_folio(eb, start);
 
 	while (len > 0) {
-		page = eb->pages[i];
+		char *kaddr;
 
-		cur = min(len, (PAGE_SIZE - offset));
-		kaddr = page_address(page);
+		cur = min(len, unit_size - offset);
+		kaddr = folio_address(eb->folios[i]);
 		if (copy_to_user_nofault(dst, kaddr + offset, cur)) {
 			ret = -EFAULT;
 			break;
@@ -4200,25 +4473,25 @@ int read_extent_buffer_to_user_nofault(const struct extent_buffer *eb,
 int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
 			 unsigned long start, unsigned long len)
 {
+	const int unit_size = folio_size(eb->folios[0]);
 	size_t cur;
 	size_t offset;
-	struct page *page;
 	char *kaddr;
 	char *ptr = (char *)ptrv;
-	unsigned long i = get_eb_page_index(start);
+	unsigned long i = get_eb_folio_index(eb, start);
 	int ret = 0;
 
 	if (check_eb_range(eb, start, len))
 		return -EINVAL;
 
-	offset = get_eb_offset_in_page(eb, start);
-
-	while (len > 0) {
-		page = eb->pages[i];
+	if (eb->addr)
+		return memcmp(ptrv, eb->addr + start, len);
 
-		cur = min(len, (PAGE_SIZE - offset));
+	offset = get_eb_offset_in_folio(eb, start);
 
-		kaddr = page_address(page);
+	while (len > 0) {
+		cur = min(len, unit_size - offset);
+		kaddr = folio_address(eb->folios[i]);
 		ret = memcmp(ptr, kaddr + offset, cur);
 		if (ret)
 			break;
@@ -4237,10 +4510,12 @@ int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
  * For regular sector size == PAGE_SIZE case, check if @page is uptodate.
  * For subpage case, check if the range covered by the eb has EXTENT_UPTODATE.
  */
-static void assert_eb_page_uptodate(const struct extent_buffer *eb,
-				    struct page *page)
+static void assert_eb_folio_uptodate(const struct extent_buffer *eb, int i)
 {
 	struct btrfs_fs_info *fs_info = eb->fs_info;
+	struct folio *folio = eb->folios[i];
+
+	ASSERT(folio);
 
 	/*
 	 * If we are using the commit root we could potentially clear a page
@@ -4254,11 +4529,14 @@ static void assert_eb_page_uptodate(const struct extent_buffer *eb,
 		return;
 
 	if (fs_info->nodesize < PAGE_SIZE) {
-		if (WARN_ON(!btrfs_subpage_test_uptodate(fs_info, page,
+		struct folio *folio = eb->folios[0];
+
+		ASSERT(i == 0);
+		if (WARN_ON(!btrfs_subpage_test_uptodate(fs_info, folio,
 							 eb->start, eb->len)))
-			btrfs_subpage_dump_bitmap(fs_info, page, eb->start, eb->len);
+			btrfs_subpage_dump_bitmap(fs_info, folio, eb->start, eb->len);
 	} else {
-		WARN_ON(!PageUptodate(page));
+		WARN_ON(!folio_test_uptodate(folio));
 	}
 }
 
@@ -4266,29 +4544,34 @@ static void __write_extent_buffer(const struct extent_buffer *eb,
 				  const void *srcv, unsigned long start,
 				  unsigned long len, bool use_memmove)
 {
+	const int unit_size = folio_size(eb->folios[0]);
 	size_t cur;
 	size_t offset;
-	struct page *page;
 	char *kaddr;
 	char *src = (char *)srcv;
-	unsigned long i = get_eb_page_index(start);
+	unsigned long i = get_eb_folio_index(eb, start);
 	/* For unmapped (dummy) ebs, no need to check their uptodate status. */
 	const bool check_uptodate = !test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags);
 
-	WARN_ON(test_bit(EXTENT_BUFFER_NO_CHECK, &eb->bflags));
-
 	if (check_eb_range(eb, start, len))
 		return;
 
-	offset = get_eb_offset_in_page(eb, start);
+	if (eb->addr) {
+		if (use_memmove)
+			memmove(eb->addr + start, srcv, len);
+		else
+			memcpy(eb->addr + start, srcv, len);
+		return;
+	}
+
+	offset = get_eb_offset_in_folio(eb, start);
 
 	while (len > 0) {
-		page = eb->pages[i];
 		if (check_uptodate)
-			assert_eb_page_uptodate(eb, page);
+			assert_eb_folio_uptodate(eb, i);
 
-		cur = min(len, PAGE_SIZE - offset);
-		kaddr = page_address(page);
+		cur = min(len, unit_size - offset);
+		kaddr = folio_address(eb->folios[i]);
 		if (use_memmove)
 			memmove(kaddr + offset, src, cur);
 		else
@@ -4310,16 +4593,21 @@ void write_extent_buffer(const struct extent_buffer *eb, const void *srcv,
 static void memset_extent_buffer(const struct extent_buffer *eb, int c,
 				 unsigned long start, unsigned long len)
 {
+	const int unit_size = folio_size(eb->folios[0]);
 	unsigned long cur = start;
 
+	if (eb->addr) {
+		memset(eb->addr + start, c, len);
+		return;
+	}
+
 	while (cur < start + len) {
-		unsigned long index = get_eb_page_index(cur);
-		unsigned int offset = get_eb_offset_in_page(eb, cur);
-		unsigned int cur_len = min(start + len - cur, PAGE_SIZE - offset);
-		struct page *page = eb->pages[index];
+		unsigned long index = get_eb_folio_index(eb, cur);
+		unsigned int offset = get_eb_offset_in_folio(eb, cur);
+		unsigned int cur_len = min(start + len - cur, unit_size - offset);
 
-		assert_eb_page_uptodate(eb, page);
-		memset(page_address(page) + offset, c, cur_len);
+		assert_eb_folio_uptodate(eb, index);
+		memset(folio_address(eb->folios[index]) + offset, c, cur_len);
 
 		cur += cur_len;
 	}
@@ -4336,15 +4624,16 @@ void memzero_extent_buffer(const struct extent_buffer *eb, unsigned long start,
 void copy_extent_buffer_full(const struct extent_buffer *dst,
 			     const struct extent_buffer *src)
 {
+	const int unit_size = folio_size(src->folios[0]);
 	unsigned long cur = 0;
 
 	ASSERT(dst->len == src->len);
 
 	while (cur < src->len) {
-		unsigned long index = get_eb_page_index(cur);
-		unsigned long offset = get_eb_offset_in_page(src, cur);
-		unsigned long cur_len = min(src->len, PAGE_SIZE - offset);
-		void *addr = page_address(src->pages[index]) + offset;
+		unsigned long index = get_eb_folio_index(src, cur);
+		unsigned long offset = get_eb_offset_in_folio(src, cur);
+		unsigned long cur_len = min(src->len, unit_size - offset);
+		void *addr = folio_address(src->folios[index]) + offset;
 
 		write_extent_buffer(dst, addr, cur, cur_len);
 
@@ -4357,12 +4646,12 @@ void copy_extent_buffer(const struct extent_buffer *dst,
 			unsigned long dst_offset, unsigned long src_offset,
 			unsigned long len)
 {
+	const int unit_size = folio_size(dst->folios[0]);
 	u64 dst_len = dst->len;
 	size_t cur;
 	size_t offset;
-	struct page *page;
 	char *kaddr;
-	unsigned long i = get_eb_page_index(dst_offset);
+	unsigned long i = get_eb_folio_index(dst, dst_offset);
 
 	if (check_eb_range(dst, dst_offset, len) ||
 	    check_eb_range(src, src_offset, len))
@@ -4370,15 +4659,14 @@ void copy_extent_buffer(const struct extent_buffer *dst,
 
 	WARN_ON(src->len != dst_len);
 
-	offset = get_eb_offset_in_page(dst, dst_offset);
+	offset = get_eb_offset_in_folio(dst, dst_offset);
 
 	while (len > 0) {
-		page = dst->pages[i];
-		assert_eb_page_uptodate(dst, page);
+		assert_eb_folio_uptodate(dst, i);
 
-		cur = min(len, (unsigned long)(PAGE_SIZE - offset));
+		cur = min(len, (unsigned long)(unit_size - offset));
 
-		kaddr = page_address(page);
+		kaddr = folio_address(dst->folios[i]);
 		read_extent_buffer(src, kaddr + offset, src_offset, cur);
 
 		src_offset += cur;
@@ -4389,22 +4677,22 @@ void copy_extent_buffer(const struct extent_buffer *dst,
 }
 
 /*
- * Calculate the page and offset of the byte containing the given bit number.
+ * Calculate the folio and offset of the byte containing the given bit number.
  *
  * @eb:           the extent buffer
  * @start:        offset of the bitmap item in the extent buffer
  * @nr:           bit number
- * @page_index:   return index of the page in the extent buffer that contains
+ * @folio_index:  return index of the folio in the extent buffer that contains
  *                the given bit number
- * @page_offset:  return offset into the page given by page_index
+ * @folio_offset: return offset into the folio given by folio_index
  *
  * This helper hides the ugliness of finding the byte in an extent buffer which
  * contains a given bit.
  */
 static inline void eb_bitmap_offset(const struct extent_buffer *eb,
 				    unsigned long start, unsigned long nr,
-				    unsigned long *page_index,
-				    size_t *page_offset)
+				    unsigned long *folio_index,
+				    size_t *folio_offset)
 {
 	size_t byte_offset = BIT_BYTE(nr);
 	size_t offset;
@@ -4414,10 +4702,10 @@ static inline void eb_bitmap_offset(const struct extent_buffer *eb,
 	 * the bitmap item in the extent buffer + the offset of the byte in the
 	 * bitmap item.
 	 */
-	offset = start + offset_in_page(eb->start) + byte_offset;
+	offset = start + offset_in_folio(eb->folios[0], eb->start) + byte_offset;
 
-	*page_index = offset >> PAGE_SHIFT;
-	*page_offset = offset_in_page(offset);
+	*folio_index = offset >> folio_shift(eb->folios[0]);
+	*folio_offset = offset_in_folio(eb->folios[0], offset);
 }
 
 /*
@@ -4430,25 +4718,23 @@ static inline void eb_bitmap_offset(const struct extent_buffer *eb,
 int extent_buffer_test_bit(const struct extent_buffer *eb, unsigned long start,
 			   unsigned long nr)
 {
-	u8 *kaddr;
-	struct page *page;
 	unsigned long i;
 	size_t offset;
+	u8 *kaddr;
 
 	eb_bitmap_offset(eb, start, nr, &i, &offset);
-	page = eb->pages[i];
-	assert_eb_page_uptodate(eb, page);
-	kaddr = page_address(page);
+	assert_eb_folio_uptodate(eb, i);
+	kaddr = folio_address(eb->folios[i]);
 	return 1U & (kaddr[offset] >> (nr & (BITS_PER_BYTE - 1)));
 }
 
 static u8 *extent_buffer_get_byte(const struct extent_buffer *eb, unsigned long bytenr)
 {
-	unsigned long index = get_eb_page_index(bytenr);
+	unsigned long index = get_eb_folio_index(eb, bytenr);
 
 	if (check_eb_range(eb, bytenr, 1))
 		return NULL;
-	return page_address(eb->pages[index]) + get_eb_offset_in_page(eb, bytenr);
+	return folio_address(eb->folios[index]) + get_eb_offset_in_folio(eb, bytenr);
 }
 
 /*
@@ -4533,19 +4819,30 @@ void memcpy_extent_buffer(const struct extent_buffer *dst,
 			  unsigned long dst_offset, unsigned long src_offset,
 			  unsigned long len)
 {
+	const int unit_size = folio_size(dst->folios[0]);
 	unsigned long cur_off = 0;
 
 	if (check_eb_range(dst, dst_offset, len) ||
 	    check_eb_range(dst, src_offset, len))
 		return;
 
+	if (dst->addr) {
+		const bool use_memmove = areas_overlap(src_offset, dst_offset, len);
+
+		if (use_memmove)
+			memmove(dst->addr + dst_offset, dst->addr + src_offset, len);
+		else
+			memcpy(dst->addr + dst_offset, dst->addr + src_offset, len);
+		return;
+	}
+
 	while (cur_off < len) {
 		unsigned long cur_src = cur_off + src_offset;
-		unsigned long pg_index = get_eb_page_index(cur_src);
-		unsigned long pg_off = get_eb_offset_in_page(dst, cur_src);
+		unsigned long folio_index = get_eb_folio_index(dst, cur_src);
+		unsigned long folio_off = get_eb_offset_in_folio(dst, cur_src);
 		unsigned long cur_len = min(src_offset + len - cur_src,
-					    PAGE_SIZE - pg_off);
-		void *src_addr = page_address(dst->pages[pg_index]) + pg_off;
+					    unit_size - folio_off);
+		void *src_addr = folio_address(dst->folios[folio_index]) + folio_off;
 		const bool use_memmove = areas_overlap(src_offset + cur_off,
 						       dst_offset + cur_off, cur_len);
 
@@ -4571,24 +4868,29 @@ void memmove_extent_buffer(const struct extent_buffer *dst,
 		return;
 	}
 
+	if (dst->addr) {
+		memmove(dst->addr + dst_offset, dst->addr + src_offset, len);
+		return;
+	}
+
 	while (len > 0) {
 		unsigned long src_i;
 		size_t cur;
-		size_t dst_off_in_page;
-		size_t src_off_in_page;
+		size_t dst_off_in_folio;
+		size_t src_off_in_folio;
 		void *src_addr;
 		bool use_memmove;
 
-		src_i = get_eb_page_index(src_end);
+		src_i = get_eb_folio_index(dst, src_end);
 
-		dst_off_in_page = get_eb_offset_in_page(dst, dst_end);
-		src_off_in_page = get_eb_offset_in_page(dst, src_end);
+		dst_off_in_folio = get_eb_offset_in_folio(dst, dst_end);
+		src_off_in_folio = get_eb_offset_in_folio(dst, src_end);
 
-		cur = min_t(unsigned long, len, src_off_in_page + 1);
-		cur = min(cur, dst_off_in_page + 1);
+		cur = min_t(unsigned long, len, src_off_in_folio + 1);
+		cur = min(cur, dst_off_in_folio + 1);
 
-		src_addr = page_address(dst->pages[src_i]) + src_off_in_page -
-					cur + 1;
+		src_addr = folio_address(dst->folios[src_i]) + src_off_in_folio -
+					 cur + 1;
 		use_memmove = areas_overlap(src_end - cur + 1, dst_end - cur + 1,
 					    cur);
 
@@ -4641,7 +4943,7 @@ out:
 
 static int try_release_subpage_extent_buffer(struct page *page)
 {
-	struct btrfs_fs_info *fs_info = btrfs_sb(page->mapping->host->i_sb);
+	struct btrfs_fs_info *fs_info = page_to_fs_info(page);
 	u64 cur = page_offset(page);
 	const u64 end = page_offset(page) + PAGE_SIZE;
 	int ret;
@@ -4650,7 +4952,7 @@ static int try_release_subpage_extent_buffer(struct page *page)
 		struct extent_buffer *eb = NULL;
 
 		/*
-		 * Unlike try_release_extent_buffer() which uses page->private
+		 * Unlike try_release_extent_buffer() which uses folio private
 		 * to grab buffer, for subpage case we rely on radix tree, thus
 		 * we need to ensure radix tree consistency.
 		 *
@@ -4690,43 +4992,44 @@ static int try_release_subpage_extent_buffer(struct page *page)
 
 		/*
 		 * Here we don't care about the return value, we will always
-		 * check the page private at the end.  And
+		 * check the folio private at the end.  And
 		 * release_extent_buffer() will release the refs_lock.
 		 */
 		release_extent_buffer(eb);
 	}
 	/*
-	 * Finally to check if we have cleared page private, as if we have
-	 * released all ebs in the page, the page private should be cleared now.
+	 * Finally to check if we have cleared folio private, as if we have
+	 * released all ebs in the page, the folio private should be cleared now.
 	 */
-	spin_lock(&page->mapping->private_lock);
-	if (!PagePrivate(page))
+	spin_lock(&page->mapping->i_private_lock);
+	if (!folio_test_private(page_folio(page)))
 		ret = 1;
 	else
 		ret = 0;
-	spin_unlock(&page->mapping->private_lock);
+	spin_unlock(&page->mapping->i_private_lock);
 	return ret;
 
 }
 
 int try_release_extent_buffer(struct page *page)
 {
+	struct folio *folio = page_folio(page);
 	struct extent_buffer *eb;
 
-	if (btrfs_sb(page->mapping->host->i_sb)->nodesize < PAGE_SIZE)
+	if (page_to_fs_info(page)->nodesize < PAGE_SIZE)
 		return try_release_subpage_extent_buffer(page);
 
 	/*
-	 * We need to make sure nobody is changing page->private, as we rely on
-	 * page->private as the pointer to extent buffer.
+	 * We need to make sure nobody is changing folio private, as we rely on
+	 * folio private as the pointer to extent buffer.
 	 */
-	spin_lock(&page->mapping->private_lock);
-	if (!PagePrivate(page)) {
-		spin_unlock(&page->mapping->private_lock);
+	spin_lock(&page->mapping->i_private_lock);
+	if (!folio_test_private(folio)) {
+		spin_unlock(&page->mapping->i_private_lock);
 		return 1;
 	}
 
-	eb = (struct extent_buffer *)page->private;
+	eb = folio_get_private(folio);
 	BUG_ON(!eb);
 
 	/*
@@ -4737,10 +5040,10 @@ int try_release_extent_buffer(struct page *page)
 	spin_lock(&eb->refs_lock);
 	if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
 		spin_unlock(&eb->refs_lock);
-		spin_unlock(&page->mapping->private_lock);
+		spin_unlock(&page->mapping->i_private_lock);
 		return 0;
 	}
-	spin_unlock(&page->mapping->private_lock);
+	spin_unlock(&page->mapping->i_private_lock);
 
 	/*
 	 * If tree ref isn't set then we know the ref on this eb is a real ref,