Merge tag 'for-6.8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs updates from David Sterba:
 "There are no exciting changes for users, it's been mostly API
  conversions and some fixes or refactoring.

  The mount API conversion is a base for future improvements that would
  come with VFS. Metadata processing has been converted to folios, not
  yet enabling the large folios but it's one patch away once everything
  gets tested enough.

  Core changes:

   - convert extent buffers to folios:
      - direct API conversion where possible
      - performance can drop by a few percent on metadata heavy
        workloads, the folio sizes are not constant and the calculations
        add up in the item helpers
      - both regular and subpage modes
      - data cannot be converted yet, we need to port that to iomap and
        there are some other generic changes required

   - convert mount to the new API, should not be user visible:
      - options deprecated long time ago have been removed: inode_cache,
        recovery
      - the new logic that splits mount to two phases slightly changes
        timing of device scanning for multi-device filesystems
      - LSM options will now work (like for selinux)

   - convert delayed nodes radix tree to xarray, preserving the
     preload-like logic that still allows to allocate with GFP_NOFS

   - more validation of sysfs value of scrub_speed_max

   - refactor chunk map structure, reduce size and improve performance

   - extent map refactoring, smaller data structures, improved
     performance

   - reduce size of struct extent_io_tree, embedded in several
     structures

   - temporary pages used for compression are cached and attached to a
     shrinker, this may slightly improve performance

   - in zoned mode, remove redirty extent buffer tracking, zeros are
     written in case an out-of-order is detected and proper data are
     written to the actual write pointer

   - cleanups, refactoring, error message improvements, updated tests

   - verify and update branch name or tag

   - remove unwanted text"

* tag 'for-6.8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (89 commits)
  btrfs: pass btrfs_io_geometry into btrfs_max_io_len
  btrfs: pass struct btrfs_io_geometry to set_io_stripe
  btrfs: open code set_io_stripe for RAID56
  btrfs: change block mapping to switch/case in btrfs_map_block
  btrfs: factor out block mapping for single profiles
  btrfs: factor out block mapping for RAID5/6
  btrfs: reduce scope of data_stripes in btrfs_map_block
  btrfs: factor out block mapping for RAID10
  btrfs: factor out block mapping for DUP profiles
  btrfs: factor out RAID1 block mapping
  btrfs: factor out block-mapping for RAID0
  btrfs: re-introduce struct btrfs_io_geometry
  btrfs: factor out helper for single device IO check
  btrfs: migrate btrfs_repair_io_failure() to folio interfaces
  btrfs: migrate eb_bitmap_offset() to folio interfaces
  btrfs: migrate various end io functions to folios
  btrfs: migrate subpage code to folio interfaces
  btrfs: migrate get_eb_page_index() and get_eb_offset_in_page() to folios
  btrfs: don't double put our subpage reference in alloc_extent_buffer
  btrfs: cleanup metadata page pointer usage
  ...

1 files changed, 633 insertions, 418 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index b6ff6f320198..cfd2967f04a2 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -184,22 +184,23 @@ 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,
@@ -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;
 			}
 
@@ -432,60 +434,65 @@ 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 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);
 
@@ -672,19 +683,22 @@ 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)
 {
 	unsigned int allocated;
 
 	for (allocated = 0; allocated < nr_pages;) {
 		unsigned int last = allocated;
 
-		allocated = alloc_pages_bulk_array(GFP_NOFS, nr_pages, page_array);
+		allocated = alloc_pages_bulk_array(GFP_NOFS | extra_gfp,
+						   nr_pages, page_array);
 
 		if (allocated == nr_pages)
 			return 0;
@@ -707,6 +721,26 @@ int btrfs_alloc_page_array(unsigned int nr_pages, struct page **page_array)
 	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)
@@ -861,9 +895,9 @@ 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 +908,66 @@ 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->i_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)
 {
+	struct folio *folio = page_folio(page);
 	struct btrfs_fs_info *fs_info;
 
 	ASSERT(page->mapping);
 
-	if (PagePrivate(page))
+	if (folio_test_private(folio))
 		return 0;
 
 	fs_info = btrfs_sb(page->mapping->host->i_sb);
 
-	if (btrfs_is_subpage(fs_info, page))
-		return btrfs_attach_subpage(fs_info, page, BTRFS_SUBPAGE_DATA);
+	if (btrfs_is_subpage(fs_info, page->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);
+	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 *
@@ -1001,7 +1036,7 @@ 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 +1062,7 @@ 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 +1071,7 @@ 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 +1108,7 @@ 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;
@@ -1240,7 +1274,8 @@ 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 +1287,7 @@ 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 +1340,7 @@ 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 +1360,7 @@ 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 +1387,7 @@ 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 +1412,7 @@ 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 +1420,7 @@ 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 +1642,23 @@ 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 +1707,44 @@ 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);
@@ -1725,6 +1767,7 @@ 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 folio *folio = page_folio(page);
 	int submitted = 0;
 	u64 page_start = page_offset(page);
 	int bit_start = 0;
@@ -1732,7 +1775,7 @@ 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;
@@ -1742,7 +1785,7 @@ static int submit_eb_subpage(struct page *page, struct writeback_control *wbc)
 		 * in the meantime.
 		 */
 		spin_lock(&page->mapping->i_private_lock);
-		if (!PagePrivate(page)) {
+		if (!folio_test_private(folio)) {
 			spin_unlock(&page->mapping->i_private_lock);
 			break;
 		}
@@ -1807,22 +1850,23 @@ 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)
 		return submit_eb_subpage(page, wbc);
 
 	spin_lock(&mapping->i_private_lock);
-	if (!PagePrivate(page)) {
+	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
@@ -2201,7 +2245,7 @@ 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:
@@ -2352,7 +2396,7 @@ 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 +2413,7 @@ 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
@@ -3058,14 +3102,14 @@ 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->i_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;
 		/*
@@ -3078,21 +3122,21 @@ 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
+	 * 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->i_private_lock);
+		spin_lock(&folio->mapping->i_private_lock);
 
-	if (!PagePrivate(page)) {
+	if (!folio_test_private(folio)) {
 		if (mapped)
-			spin_unlock(&page->mapping->i_private_lock);
+			spin_unlock(&folio->mapping->i_private_lock);
 		return;
 	}
 
@@ -3101,66 +3145,58 @@ 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->i_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->i_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);
 	}
 }
 
@@ -3198,9 +3234,8 @@ __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);
@@ -3214,22 +3249,22 @@ 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);
@@ -3241,23 +3276,20 @@ 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;
 	}
@@ -3268,10 +3300,10 @@ 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);
@@ -3320,20 +3352,14 @@ 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,
@@ -3361,7 +3387,7 @@ 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;
 }
 
@@ -3410,6 +3436,7 @@ 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;
 
 	/*
@@ -3421,21 +3448,21 @@ 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;
 }
 
@@ -3469,19 +3496,88 @@ 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;
 
@@ -3516,10 +3612,8 @@ 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
+	 * 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
@@ -3528,47 +3622,89 @@ 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->i_private_lock);
-		exists = grab_extent_buffer(fs_info, p);
-		if (exists) {
-			spin_unlock(&mapping->i_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);
+		btrfs_folio_inc_eb_refs(fs_info, folio);
 		spin_unlock(&mapping->i_private_lock);
 
-		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))
+		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;
+
+		if (!btrfs_folio_test_uptodate(fs_info, folio, eb->start, eb->len))
 			uptodate = 0;
 
 		/*
@@ -3581,12 +3717,13 @@ 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,
@@ -3594,9 +3731,10 @@ 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;
 	}
@@ -3609,19 +3747,46 @@ 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)
@@ -3713,31 +3878,30 @@ 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);
 }
 
@@ -3745,15 +3909,27 @@ 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)) {
+		set_bit(EXTENT_BUFFER_ZONED_ZEROOUT, &eb->bflags);
+		return;
+	}
+
 	if (!test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags))
 		return;
 
@@ -3763,30 +3939,29 @@ 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));
 
@@ -3805,34 +3980,32 @@ 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;
 
 		/*
@@ -3840,44 +4013,40 @@ 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;
@@ -3893,15 +4062,15 @@ 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;
 	}
@@ -3917,8 +4086,8 @@ 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;
@@ -3942,17 +4111,24 @@ 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);
 
@@ -3999,29 +4175,33 @@ 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;
@@ -4035,24 +4215,29 @@ 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;
@@ -4070,25 +4255,25 @@ 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);
+	if (eb->addr)
+		return memcmp(ptrv, eb->addr + start, len);
 
-	while (len > 0) {
-		page = eb->pages[i];
+	offset = get_eb_offset_in_folio(eb, start);
 
-		cur = min(len, (PAGE_SIZE - offset));
-
-		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;
@@ -4107,10 +4292,12 @@ 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
@@ -4124,11 +4311,14 @@ 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));
 	}
 }
 
@@ -4136,29 +4326,34 @@ 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
@@ -4180,16 +4375,21 @@ 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;
 	}
@@ -4206,15 +4406,16 @@ 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);
 
@@ -4227,12 +4428,12 @@ 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))
@@ -4240,15 +4441,14 @@ 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;
@@ -4259,22 +4459,22 @@ 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;
@@ -4284,10 +4484,10 @@ 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);
 }
 
 /*
@@ -4300,25 +4500,23 @@ 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);
 }
 
 /*
@@ -4403,19 +4601,30 @@ 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);
 
@@ -4441,24 +4650,29 @@ 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);
 
@@ -4520,7 +4734,7 @@ 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.
 		 *
@@ -4560,17 +4774,17 @@ 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->i_private_lock);
-	if (!PagePrivate(page))
+	if (!folio_test_private(page_folio(page)))
 		ret = 1;
 	else
 		ret = 0;
@@ -4581,22 +4795,23 @@ static int try_release_subpage_extent_buffer(struct page *page)
 
 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)
 		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->i_private_lock);
-	if (!PagePrivate(page)) {
+	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);
 
 	/*