btrfs: use metadata specific helpers to simplify extent buffer helpers

The following functions are doing metadata specific checks:

- set_extent_buffer_uptodate()
- clear_extent_buffer_uptodate()

The reason why we do not use btrfs_folio_*() helpers for those helpers
is, btrfs_is_subpage() cannot handle dummy extent buffer if nodesize >=
PAGE_SIZE but block size < PAGE_SIZE.

In that case, we do not need to attach extra bitmaps to the extent
buffer folio. But since dummy extent buffer folios are not attached to
btree inode, btrfs_is_subpage() will return true, causing problems.

And the following are using btrfs_folio_*() helpers for metadata, but
in theory we should use metadata specific checks:

- set_extent_buffer_dirty()

This is not causing problems because a dummy extent buffer should never
be marked dirty.

To make code simpler, introduce btrfs_meta_folio_*() helpers, to do
the metadata specific handling, so that we do not to open-code such
checks in above involved functions.

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

1 files changed, 14 insertions, 1 deletions

diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h
index 4de61ee93859..ee118bb2c22f 100644
--- a/fs/btrfs/subpage.h
+++ b/fs/btrfs/subpage.h
@@ -128,6 +128,13 @@ void btrfs_folio_end_lock_bitmap(const struct btrfs_fs_info *fs_info,
  * 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.
+ *
+ * Both btrfs_folio_*() and btrfs_folio_clamp_*() are for data folios.
+ *
+ * For metadata, one should use btrfs_meta_folio_*() helpers instead, and there
+ * is no clamp version for metadata helpers, as we either go subpage
+ * (nodesize < PAGE_SIZE) or go regular folio helpers (nodesize >= PAGE_SIZE,
+ * and our folio is never larger than nodesize).
  */
 #define DECLARE_BTRFS_SUBPAGE_OPS(name)					\
 void btrfs_subpage_set_##name(const struct btrfs_fs_info *fs_info,	\
@@ -147,7 +154,13 @@ void btrfs_folio_clamp_set_##name(const struct btrfs_fs_info *fs_info,	\
 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);
+		struct folio *folio, u64 start, u32 len);		\
+void btrfs_meta_folio_set_##name(const struct btrfs_fs_info *fs_info,	\
+		struct folio *folio, u64 start, u32 len);		\
+void btrfs_meta_folio_clear_##name(const struct btrfs_fs_info *fs_info,	\
+		struct folio *folio, u64 start, u32 len);		\
+bool btrfs_meta_folio_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);