[PATCH 20/21] iomap: Support multi-page folios in invalidatepage

Matthew Wilcox (Oracle)
2021-11-01T21:27:42Z

If we're punching a hole in a multi-page folio, we need to remove the
per-folio iomap data as the folio is about to be split and each page will
need its own. If a dirty folio is only partially-uptodate, the iomap
data contains the information about which blocks cannot be written back,
so assert that a dirty folio is fully uptodate.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
fs/iomap/buffered-io.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 3b93fdfedb72..9d7c91f9ec1d 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -470,13 +470,18 @@ void iomap_invalidate_folio(struct folio *folio, size_t offset, size_t len)
trace_iomap_invalidatepage(folio->mapping->host, offset, len);

/*
- * If we're invalidating the entire page, clear the dirty state from it
- * and release it to avoid unnecessary buildup of the LRU.
+ * If we're invalidating the entire folio, clear the dirty state
+ * from it and release it to avoid unnecessary buildup of the LRU.
*/
if (offset == 0 && len == folio_size(folio)) {
WARN_ON_ONCE(folio_test_writeback(folio));
folio_cancel_dirty(folio);
iomap_page_release(folio);
+ } else if (folio_test_multi(folio)) {
+ /* Must release the iop so the page can be split */
+ WARN_ON_ONCE(!folio_test_uptodate(folio) &&
+ folio_test_dirty(folio));
+ iomap_page_release(folio);
}
}
EXPORT_SYMBOL_GPL(iomap_invalidate_folio);
--
2.33.0