nilfs2: replace obvious uses of b_page with b_folio

These places just use b_page to get to the buffer's address_space or the
index of the page the buffer is in.

Link: https://lkml.kernel.org/r/20221215214402.3522366-11-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/nilfs2/btnode.c

@@ -188,7 +188,7 @@ int nilfs_btnode_prepare_change_key(struct address_space *btnc,
 		struct page *opage = obh->b_page;
 		lock_page(opage);
 retry:
-		/* BUG_ON(oldkey != obh->b_page->index); */
+		/* BUG_ON(oldkey != obh->b_folio->index); */
 		if (unlikely(oldkey != opage->index))
 			NILFS_PAGE_BUG(opage,
 				       "invalid oldkey %lld (newkey=%lld)",

fs/nilfs2/btree.c

@@ -398,7 +398,7 @@ int nilfs_btree_broken_node_block(struct buffer_head *bh)
 	if (buffer_nilfs_checked(bh))
 		return 0;
 
-	inode = bh->b_page->mapping->host;
+	inode = bh->b_folio->mapping->host;
 	ret = nilfs_btree_node_broken((struct nilfs_btree_node *)bh->b_data,
 				      bh->b_size, inode, bh->b_blocknr);
 	if (likely(!ret))

fs/nilfs2/gcinode.c

@@ -140,7 +140,7 @@ int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *bh)
 {
 	wait_on_buffer(bh);
 	if (!buffer_uptodate(bh)) {
-		struct inode *inode = bh->b_page->mapping->host;
+		struct inode *inode = bh->b_folio->mapping->host;
 
 		nilfs_err(inode->i_sb,
 			  "I/O error reading %s block for GC (ino=%lu, vblocknr=%llu)",

fs/nilfs2/mdt.c

@@ -563,7 +563,7 @@ int nilfs_mdt_freeze_buffer(struct inode *inode, struct buffer_head *bh)
 	struct page *page;
 	int blkbits = inode->i_blkbits;
 
-	page = grab_cache_page(shadow->inode->i_mapping, bh->b_page->index);
+	page = grab_cache_page(shadow->inode->i_mapping, bh->b_folio->index);
 	if (!page)
 		return -ENOMEM;
 
@@ -595,7 +595,7 @@ nilfs_mdt_get_frozen_buffer(struct inode *inode, struct buffer_head *bh)
 	struct page *page;
 	int n;
 
-	page = find_lock_page(shadow->inode->i_mapping, bh->b_page->index);
+	page = find_lock_page(shadow->inode->i_mapping, bh->b_folio->index);
 	if (page) {
 		if (page_has_buffers(page)) {
 			n = bh_offset(bh) >> inode->i_blkbits;

fs/nilfs2/segment.c

@@ -1581,7 +1581,7 @@ nilfs_segctor_update_payload_blocknr(struct nilfs_sc_info *sci,
 			nblocks = le32_to_cpu(finfo->fi_nblocks);
 			ndatablk = le32_to_cpu(finfo->fi_ndatablk);
 
-			inode = bh->b_page->mapping->host;
+			inode = bh->b_folio->mapping->host;
 
 			if (mode == SC_LSEG_DSYNC)
 				sc_op = &nilfs_sc_dsync_ops;