1 files changed, 35 insertions, 24 deletions

diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h
index 3042c5ea840a..ee0710eb13fd 100644
--- a/fs/btrfs/subpage.h
+++ b/fs/btrfs/subpage.h
@@ -32,9 +32,31 @@ struct folio;
 enum {
 	btrfs_bitmap_nr_uptodate = 0,
 	btrfs_bitmap_nr_dirty,
+
+	/*
+	 * This can be changed to atomic eventually.  But this change will rely
+	 * on the async delalloc range rework for locked bitmap.  As async
+	 * delalloc can unlock its range and mark blocks writeback at random
+	 * timing.
+	 */
 	btrfs_bitmap_nr_writeback,
+
+	/*
+	 * The ordered and checked flags are for COW fixup, already marked
+	 * deprecated, and will be removed eventually.
+	 */
 	btrfs_bitmap_nr_ordered,
 	btrfs_bitmap_nr_checked,
+
+	/*
+	 * The locked bit is for async delalloc range (compression), currently
+	 * async extent is queued with the range locked, until the compression
+	 * is done.
+	 * So an async extent can unlock the range at any random timing.
+	 *
+	 * This will need a rework on the async extent lifespan (mark writeback
+	 * and do compression) before deprecating this flag.
+	 */
 	btrfs_bitmap_nr_locked,
 	btrfs_bitmap_nr_max
 };
@@ -43,7 +65,7 @@ enum {
  * Structure to trace status of each sector inside a page, attached to
  * page::private for both data and metadata inodes.
  */
-struct btrfs_subpage {
+struct btrfs_folio_state {
 	/* Common members for both data and metadata pages */
 	spinlock_t lock;
 	union {
@@ -51,7 +73,7 @@ struct btrfs_subpage {
 		 * Structures only used by metadata
 		 *
 		 * @eb_refs should only be operated under private_lock, as it
-		 * manages whether the subpage can be detached.
+		 * manages whether the btrfs_folio_state can be detached.
 		 */
 		atomic_t eb_refs;
 
@@ -65,12 +87,11 @@ struct btrfs_subpage {
 	unsigned long bitmaps[];
 };
 
-enum btrfs_subpage_type {
+enum btrfs_folio_type {
 	BTRFS_SUBPAGE_METADATA,
 	BTRFS_SUBPAGE_DATA,
 };
 
-#if PAGE_SIZE > BTRFS_MIN_BLOCKSIZE
 /*
  * Subpage support for metadata is more complex, as we can have dummy extent
  * buffers, where folios have no mapping to determine the owning inode.
@@ -91,29 +112,19 @@ static inline bool btrfs_is_subpage(const struct btrfs_fs_info *fs_info,
 		ASSERT(is_data_inode(BTRFS_I(folio->mapping->host)));
 	return fs_info->sectorsize < folio_size(folio);
 }
-#else
-static inline bool btrfs_meta_is_subpage(const struct btrfs_fs_info *fs_info)
-{
-	return false;
-}
-static inline bool btrfs_is_subpage(const struct btrfs_fs_info *fs_info,
-				    struct folio *folio)
-{
-	if (folio->mapping && folio->mapping->host)
-		ASSERT(is_data_inode(BTRFS_I(folio->mapping->host)));
-	return false;
-}
-#endif
 
-int btrfs_attach_subpage(const struct btrfs_fs_info *fs_info,
-			 struct folio *folio, enum btrfs_subpage_type type);
-void btrfs_detach_subpage(const struct btrfs_fs_info *fs_info, struct folio *folio,
-			  enum btrfs_subpage_type type);
+int btrfs_attach_folio_state(const struct btrfs_fs_info *fs_info,
+			     struct folio *folio, enum btrfs_folio_type type);
+void btrfs_detach_folio_state(const struct btrfs_fs_info *fs_info, struct folio *folio,
+			      enum btrfs_folio_type type);
 
 /* Allocate additional data where page represents more than one sector */
-struct btrfs_subpage *btrfs_alloc_subpage(const struct btrfs_fs_info *fs_info,
-				size_t fsize, enum btrfs_subpage_type type);
-void btrfs_free_subpage(struct btrfs_subpage *subpage);
+struct btrfs_folio_state *btrfs_alloc_folio_state(const struct btrfs_fs_info *fs_info,
+						  size_t fsize, enum btrfs_folio_type type);
+static inline void btrfs_free_folio_state(struct btrfs_folio_state *bfs)
+{
+	kfree(bfs);
+}
 
 void btrfs_folio_inc_eb_refs(const struct btrfs_fs_info *fs_info, struct folio *folio);
 void btrfs_folio_dec_eb_refs(const struct btrfs_fs_info *fs_info, struct folio *folio);