6.12-stable review patch. If anyone has any objections, please let me know.
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From: Matthew Wilcox (Oracle) willy@infradead.org
commit 03ddd7725ed1b39cf9251e1a420559f25dac49b3 upstream.
The migration code used to be able to migrate dirty 9p folios by writing them back using writepage. When the writepage method was removed, we neglected to add a migrate_folio method, which means that dirty 9p folios have been unmovable ever since. This reduced our success at defragmenting memory on machines which use 9p heavily.
Fixes: 80105ed2fd27 (9p: Use netfslib read/write_iter) Cc: stable@vger.kernel.org Cc: David Howells dhowells@redhat.com Cc: v9fs@lists.linux.dev Signed-off-by: "Matthew Wilcox (Oracle)" willy@infradead.org Link: https://lore.kernel.org/r/20250402150005.2309458-2-willy@infradead.org Acked-by: Dominique Martinet asmadeus@codewreck.org Reviewed-by: David Howells dhowells@redhat.com Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/9p/vfs_addr.c | 1 + 1 file changed, 1 insertion(+)
--- a/fs/9p/vfs_addr.c +++ b/fs/9p/vfs_addr.c @@ -160,4 +160,5 @@ const struct address_space_operations v9 .invalidate_folio = netfs_invalidate_folio, .direct_IO = noop_direct_IO, .writepages = netfs_writepages, + .migrate_folio = filemap_migrate_folio, };