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migrate: Remove call to ->writepage

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

Signed-off-by: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Link: https://lore.kernel.org/r/20250402150005.2309458-4-willy@infradead.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2025-04-02 15:59:57 +01:00 committed by Christian Brauner
parent e300830fcc
commit 7ee3647243
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1 changed files with 7 additions and 53 deletions
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60
mm/migrate.c
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@ -944,67 +944,21 @@ int filemap_migrate_folio(struct address_space *mapping,
} }
EXPORT_SYMBOL_GPL(filemap_migrate_folio); 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. * Default handling if a filesystem does not provide a migration function.
*/ */
static int fallback_migrate_folio(struct address_space *mapping, static int fallback_migrate_folio(struct address_space *mapping,
struct folio *dst, struct folio *src, enum migrate_mode mode) struct folio *dst, struct folio *src, enum migrate_mode mode)
{ {
if (folio_test_dirty(src)) { WARN_ONCE(mapping->a_ops->writepages,
/* Only writeback folios in full synchronous migration */ "%ps does not implement migrate_folio\n",
switch (mode) { mapping->a_ops);
case MIGRATE_SYNC: if (folio_test_dirty(src))
break; return -EBUSY;
default:
return -EBUSY;
}
return writeout(mapping, src);
}
/* /*
* Buffers may be managed in a filesystem specific way. * Filesystem may have private data at folio->private that we
* We must have no buffers or drop them. * can't migrate automatically.
*/ */
if (!filemap_release_folio(src, GFP_KERNEL)) if (!filemap_release_folio(src, GFP_KERNEL))
return mode == MIGRATE_SYNC ? -EAGAIN : -EBUSY; return mode == MIGRATE_SYNC ? -EAGAIN : -EBUSY;