Unverified Commit 7ee36472 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Christian Brauner
Browse files

migrate: Remove call to ->writepage 



The writepage callback is going away; filesystems must implement
migrate_folio or else dirty folios will not be migratable.

Signed-off-by: default avatar"Matthew Wilcox (Oracle)" <willy@infradead.org>
Link: https://lore.kernel.org/r/20250402150005.2309458-4-willy@infradead.org


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent e300830f

mm/migrate.c

+7 −53
Original line number Diff line number Diff line
@@ -944,67 +944,21 @@ int filemap_migrate_folio(struct address_space *mapping, 
}

EXPORT_SYMBOL_GPL(filemap_migrate_folio);



/*

 * Writeback a folio to clean the dirty state

 */

static int writeout(struct address_space *mapping, struct folio *folio)

{

	struct writeback_control wbc = {

		.sync_mode = WB_SYNC_NONE,

		.nr_to_write = 1,

		.range_start = 0,

		.range_end = LLONG_MAX,

		.for_reclaim = 1

	};

	int rc;



	if (!mapping->a_ops->writepage)

		/* No write method for the address space */

		return -EINVAL;



	if (!folio_clear_dirty_for_io(folio))

		/* Someone else already triggered a write */

		return -EAGAIN;



	/*

	 * A dirty folio may imply that the underlying filesystem has

	 * the folio on some queue. So the folio must be clean for

	 * migration. Writeout may mean we lose the lock and the

	 * folio state is no longer what we checked for earlier.

	 * At this point we know that the migration attempt cannot

	 * be successful.

	 */

	remove_migration_ptes(folio, folio, 0);



	rc = mapping->a_ops->writepage(&folio->page, &wbc);



	if (rc != AOP_WRITEPAGE_ACTIVATE)

		/* unlocked. Relock */

		folio_lock(folio);



	return (rc < 0) ? -EIO : -EAGAIN;

}



/*

 * Default handling if a filesystem does not provide a migration function.

 */

static int fallback_migrate_folio(struct address_space *mapping,

		struct folio *dst, struct folio *src, enum migrate_mode mode)

{

	if (folio_test_dirty(src)) {

		/* Only writeback folios in full synchronous migration */

		switch (mode) {

		case MIGRATE_SYNC:

			break;

		default:

	WARN_ONCE(mapping->a_ops->writepages,

			"%ps does not implement migrate_folio\n",

			mapping->a_ops);

	if (folio_test_dirty(src))

		return -EBUSY;

		}

		return writeout(mapping, src);

	}



	/*

	 * Buffers may be managed in a filesystem specific way.

	 * We must have no buffers or drop them.

	 * Filesystem may have private data at folio->private that we

	 * can't migrate automatically.

	 */

	if (!filemap_release_folio(src, GFP_KERNEL))

		return mode == MIGRATE_SYNC ? -EAGAIN : -EBUSY;