btrfs: migrate subpage code to folio interfaces

Although subpage itself is conflicting with higher folio, since subpage
(sectorsize < PAGE_SIZE and nodesize < PAGE_SIZE) means we will never
need higher order folio, there is a hidden pitfall:

- btrfs_page_*() helpers

Those helpers are an abstraction to handle both subpage and non-subpage
cases, which means we're going to pass pages pointers to those helpers.

And since those helpers are shared between data and metadata paths, it's
unavoidable to let them to handle folios, including higher order
folios).

Meanwhile for true subpage case, we should only have a single page
backed folios anyway, thus add a new ASSERT() for btrfs_subpage_assert()
to ensure that.

Also since those helpers are shared between both data and metadata, add
some extra ASSERT()s for data path to make sure we only get single page
backed folio for now.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 36 insertions, 38 deletions

diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h
index facd5c808e6f..793c2b314a58 100644
--- a/fs/btrfs/subpage.h
+++ b/fs/btrfs/subpage.h
@@ -77,9 +77,8 @@ bool btrfs_is_subpage(const struct btrfs_fs_info *fs_info, struct address_space
 
 void btrfs_init_subpage_info(struct btrfs_subpage_info *subpage_info, u32 sectorsize);
 int btrfs_attach_subpage(const struct btrfs_fs_info *fs_info,
-			 struct page *page, enum btrfs_subpage_type type);
-void btrfs_detach_subpage(const struct btrfs_fs_info *fs_info,
-			  struct page *page);
+			 struct folio *folio, enum btrfs_subpage_type type);
+void btrfs_detach_subpage(const struct btrfs_fs_info *fs_info, struct folio *folio);
 
 /* Allocate additional data where page represents more than one sector */
 struct btrfs_subpage *btrfs_alloc_subpage(const struct btrfs_fs_info *fs_info,
@@ -90,52 +89,52 @@ void btrfs_folio_inc_eb_refs(const struct btrfs_fs_info *fs_info, struct folio *
 void btrfs_folio_dec_eb_refs(const struct btrfs_fs_info *fs_info, struct folio *folio);
 
 void btrfs_subpage_start_reader(const struct btrfs_fs_info *fs_info,
-		struct page *page, u64 start, u32 len);
+				struct folio *folio, u64 start, u32 len);
 void btrfs_subpage_end_reader(const struct btrfs_fs_info *fs_info,
-		struct page *page, u64 start, u32 len);
+			      struct folio *folio, u64 start, u32 len);
 
 void btrfs_subpage_start_writer(const struct btrfs_fs_info *fs_info,
-		struct page *page, u64 start, u32 len);
+				struct folio *folio, u64 start, u32 len);
 bool btrfs_subpage_end_and_test_writer(const struct btrfs_fs_info *fs_info,
-		struct page *page, u64 start, u32 len);
-int btrfs_page_start_writer_lock(const struct btrfs_fs_info *fs_info,
-		struct page *page, u64 start, u32 len);
-void btrfs_page_end_writer_lock(const struct btrfs_fs_info *fs_info,
-		struct page *page, u64 start, u32 len);
+				       struct folio *folio, u64 start, u32 len);
+int btrfs_folio_start_writer_lock(const struct btrfs_fs_info *fs_info,
+				  struct folio *folio, u64 start, u32 len);
+void btrfs_folio_end_writer_lock(const struct btrfs_fs_info *fs_info,
+				 struct folio *folio, u64 start, u32 len);
 
 /*
  * Template for subpage related operations.
  *
- * btrfs_subpage_*() are for call sites where the page has subpage attached and
- * the range is ensured to be inside the page.
+ * btrfs_subpage_*() are for call sites where the folio has subpage attached and
+ * the range is ensured to be inside the folio's single page.
  *
- * btrfs_page_*() are for call sites where the page can either be subpage
- * specific or regular page. The function will handle both cases.
- * But the range still needs to be inside the page.
+ * btrfs_folio_*() are for call sites where the page can either be subpage
+ * specific or regular folios. The function will handle both cases.
+ * But the range still needs to be inside one single page.
  *
- * btrfs_page_clamp_*() are similar to btrfs_page_*(), except the range doesn't
+ * btrfs_folio_clamp_*() are similar to btrfs_folio_*(), except the range doesn't
  * need to be inside the page. Those functions will truncate the range
  * automatically.
  */
 #define DECLARE_BTRFS_SUBPAGE_OPS(name)					\
 void btrfs_subpage_set_##name(const struct btrfs_fs_info *fs_info,	\
-		struct page *page, u64 start, u32 len);			\
+		struct folio *folio, u64 start, u32 len);			\
 void btrfs_subpage_clear_##name(const struct btrfs_fs_info *fs_info,	\
-		struct page *page, u64 start, u32 len);			\
+		struct folio *folio, u64 start, u32 len);			\
 bool btrfs_subpage_test_##name(const struct btrfs_fs_info *fs_info,	\
-		struct page *page, u64 start, u32 len);			\
-void btrfs_page_set_##name(const struct btrfs_fs_info *fs_info,		\
-		struct page *page, u64 start, u32 len);			\
-void btrfs_page_clear_##name(const struct btrfs_fs_info *fs_info,	\
-		struct page *page, u64 start, u32 len);			\
-bool btrfs_page_test_##name(const struct btrfs_fs_info *fs_info,	\
-		struct page *page, u64 start, u32 len);			\
-void btrfs_page_clamp_set_##name(const struct btrfs_fs_info *fs_info,	\
-		struct page *page, u64 start, u32 len);			\
-void btrfs_page_clamp_clear_##name(const struct btrfs_fs_info *fs_info,	\
-		struct page *page, u64 start, u32 len);			\
-bool btrfs_page_clamp_test_##name(const struct btrfs_fs_info *fs_info,	\
-		struct page *page, u64 start, u32 len);
+		struct folio *folio, u64 start, u32 len);			\
+void btrfs_folio_set_##name(const struct btrfs_fs_info *fs_info,	\
+		struct folio *folio, u64 start, u32 len);			\
+void btrfs_folio_clear_##name(const struct btrfs_fs_info *fs_info,	\
+		struct folio *folio, u64 start, u32 len);			\
+bool btrfs_folio_test_##name(const struct btrfs_fs_info *fs_info,	\
+		struct folio *folio, u64 start, u32 len);			\
+void btrfs_folio_clamp_set_##name(const struct btrfs_fs_info *fs_info,	\
+		struct folio *folio, u64 start, u32 len);			\
+void btrfs_folio_clamp_clear_##name(const struct btrfs_fs_info *fs_info,	\
+		struct folio *folio, u64 start, u32 len);			\
+bool btrfs_folio_clamp_test_##name(const struct btrfs_fs_info *fs_info,	\
+		struct folio *folio, u64 start, u32 len);
 
 DECLARE_BTRFS_SUBPAGE_OPS(uptodate);
 DECLARE_BTRFS_SUBPAGE_OPS(dirty);
@@ -144,13 +143,12 @@ DECLARE_BTRFS_SUBPAGE_OPS(ordered);
 DECLARE_BTRFS_SUBPAGE_OPS(checked);
 
 bool btrfs_subpage_clear_and_test_dirty(const struct btrfs_fs_info *fs_info,
-		struct page *page, u64 start, u32 len);
+					struct folio *folio, u64 start, u32 len);
 
-void btrfs_page_assert_not_dirty(const struct btrfs_fs_info *fs_info,
-				 struct page *page);
-void btrfs_page_unlock_writer(struct btrfs_fs_info *fs_info, struct page *page,
-			      u64 start, u32 len);
+void btrfs_folio_assert_not_dirty(const struct btrfs_fs_info *fs_info, struct folio *folio);
+void btrfs_folio_unlock_writer(struct btrfs_fs_info *fs_info,
+			       struct folio *folio, u64 start, u32 len);
 void __cold btrfs_subpage_dump_bitmap(const struct btrfs_fs_info *fs_info,
-				      struct page *page, u64 start, u32 len);
+				      struct folio *folio, u64 start, u32 len);
 
 #endif