fs: Switch inode_has_buffers() to take mapping_metadata_bhs

As part of a move towards placing mapping_metadata_bhs in fs-private
inode part, switch inode_has_buffers() to take mapping_metadata_bhs
and rename the function to mmb_has_buffers().

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260326095354.16340-74-jack@suse.cz
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: jankara

fs/buffer.c

@@ -468,7 +468,7 @@ EXPORT_SYMBOL(mark_buffer_async_write);
  * written back and waited upon before fsync() returns.
  *
  * The functions mark_buffer_dirty_inode(), fsync_inode_buffers(),
- * inode_has_buffers() and invalidate_inode_buffers() are provided for the
+ * mmb_has_buffers() and invalidate_inode_buffers() are provided for the
  * management of a list of dependent buffers in mapping_metadata_bhs struct.
  *
  * The locking is a little subtle: The list of buffer heads is protected by
@@ -526,11 +526,11 @@ static void remove_assoc_queue(struct buffer_head *bh)
 	}
 }
 
-int inode_has_buffers(struct inode *inode)
+bool mmb_has_buffers(struct mapping_metadata_bhs *mmb)
 {
-	return !list_empty(&inode->i_data.i_metadata_bhs.list);
+	return !list_empty(&mmb->list);
 }
-EXPORT_SYMBOL_GPL(inode_has_buffers);
+EXPORT_SYMBOL_GPL(mmb_has_buffers);
 
 /**
  * sync_mapping_buffers - write out & wait upon a mapping's "associated" buffers
@@ -561,7 +561,7 @@ int sync_mapping_buffers(struct address_space *mapping)
 	struct blk_plug plug;
 	LIST_HEAD(tmp);
 
-	if (list_empty(&mmb->list))
+	if (!mmb_has_buffers(mmb))
 		return 0;
 
 	blk_start_plug(&plug);
@@ -803,9 +803,9 @@ EXPORT_SYMBOL(block_dirty_folio);
  */
 void invalidate_inode_buffers(struct inode *inode)
 {
-	if (inode_has_buffers(inode)) {
-		struct mapping_metadata_bhs *mmb = &inode->i_data.i_metadata_bhs;
+	struct mapping_metadata_bhs *mmb = &inode->i_data.i_metadata_bhs;
 
+	if (mmb_has_buffers(mmb)) {
 		spin_lock(&mmb->lock);
 		while (!list_empty(&mmb->list))
 			__remove_assoc_queue(mmb, BH_ENTRY(mmb->list.next));

fs/ext4/inode.c

@@ -3436,7 +3436,7 @@ static bool ext4_inode_datasync_dirty(struct inode *inode)
 	}
 
 	/* Any metadata buffers to write? */
-	if (inode_has_buffers(inode))
+	if (mmb_has_buffers(&inode->i_mapping->i_metadata_bhs))
 		return true;
 	return inode_state_read_once(inode) & I_DIRTY_DATASYNC;
 }

include/linux/buffer_head.h

@@ -515,7 +515,7 @@ bool block_dirty_folio(struct address_space *mapping, struct folio *folio);
 
 void buffer_init(void);
 bool try_to_free_buffers(struct folio *folio);
-int inode_has_buffers(struct inode *inode);
+bool mmb_has_buffers(struct mapping_metadata_bhs *mmb);
 void invalidate_inode_buffers(struct inode *inode);
 int sync_mapping_buffers(struct address_space *mapping);
 void invalidate_bh_lrus(void);