Ocfs2 devel - Jun 2022 - [PATCH v2 12/19] btrfs: Convert btrfs_migratepage to migrate_folio

Use filemap_migrate_folio() to do the bulk of the work, and then copy
the ordered flag across if needed.

Signed-off-by: Matthew Wilcox (Oracle) <willy at infradead.org>
Reviewed-by: Christoph Hellwig <hch at lst.de>
---
 fs/btrfs/inode.c | 26 +++++++++-----------------
 1 file changed, 9 insertions(+), 17 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 81737eff92f3..5f41d869c648 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8255,30 +8255,24 @@ static bool btrfs_release_folio(struct folio *folio,
gfp_t gfp_flags)
 }
 
 #ifdef CONFIG_MIGRATION
-static int btrfs_migratepage(struct address_space *mapping,
-			     struct page *newpage, struct page *page,
+static int btrfs_migrate_folio(struct address_space *mapping,
+			     struct folio *dst, struct folio *src,
 			     enum migrate_mode mode)
 {
-	int ret;
+	int ret = filemap_migrate_folio(mapping, dst, src, mode);
 
-	ret = migrate_page_move_mapping(mapping, newpage, page, 0);
 	if (ret != MIGRATEPAGE_SUCCESS)
 		return ret;
 
-	if (page_has_private(page))
-		attach_page_private(newpage, detach_page_private(page));
-
-	if (PageOrdered(page)) {
-		ClearPageOrdered(page);
-		SetPageOrdered(newpage);
+	if (folio_test_ordered(src)) {
+		folio_clear_ordered(src);
+		folio_set_ordered(dst);
 	}
 
-	if (mode != MIGRATE_SYNC_NO_COPY)
-		migrate_page_copy(newpage, page);
-	else
-		migrate_page_states(newpage, page);
 	return MIGRATEPAGE_SUCCESS;
 }
+#else
+#define btrfs_migrate_folio NULL
 #endif
 
 static void btrfs_invalidate_folio(struct folio *folio, size_t offset,
@@ -11422,9 +11416,7 @@ static const struct address_space_operations btrfs_aops
= {
 	.direct_IO	= noop_direct_IO,
 	.invalidate_folio = btrfs_invalidate_folio,
 	.release_folio	= btrfs_release_folio,
-#ifdef CONFIG_MIGRATION
-	.migratepage	= btrfs_migratepage,
-#endif
+	.migrate_folio	= btrfs_migrate_folio,
 	.dirty_folio	= filemap_dirty_folio,
 	.error_remove_page = generic_error_remove_page,
 	.swap_activate	= btrfs_swap_activate,
-- 
2.35.1

On Wed, Jun 08, 2022 at 04:02:42PM +0100, Matthew Wilcox (Oracle)
wrote:
> Use filemap_migrate_folio() to do the bulk of the work, and then copy
> the ordered flag across if needed.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy at infradead.org>
> Reviewed-by: Christoph Hellwig <hch at lst.de>
Acked-by: David Sterba <dsterba at suse.com>
> +static int btrfs_migrate_folio(struct address_space *mapping,
> +			     struct folio *dst, struct folio *src,
>  			     enum migrate_mode mode)
>  {
> -	int ret;
> +	int ret = filemap_migrate_folio(mapping, dst, src, mode);
>  
> -	ret = migrate_page_move_mapping(mapping, newpage, page, 0);
>  	if (ret != MIGRATEPAGE_SUCCESS)
>  		return ret;
>  
> -	if (page_has_private(page))
> -		attach_page_private(newpage, detach_page_private(page));
If I'm reading it correctly, the private pointer does not need to be set
like that anymore because it's done somewhere during the
filemap_migrate_folio() call.
> -
> -	if (PageOrdered(page)) {
> -		ClearPageOrdered(page);
> -		SetPageOrdered(newpage);
> +	if (folio_test_ordered(src)) {
> +		folio_clear_ordered(src);
> +		folio_set_ordered(dst);
>  	}