From:   "Matthew Wilcox (Oracle)" <willy@infradead.org>
To:     "Darrick J. Wong" <djwong@kernel.org>
Cc:     "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>
Subject: [PATCH v3 24/25] iomap: Support large folios in invalidatepage
Date:   Thu, 16 Dec 2021 21:07:14 +0000
Message-Id: <20211216210715.3801857-25-willy@infradead.org>
In-Reply-To: <20211216210715.3801857-1-willy@infradead.org>
References: <20211216210715.3801857-1-willy@infradead.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

If we're punching a hole in a large 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>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.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 b2f6e5991eb0..36ccb903db92 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -481,13 +481,18 @@ 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_large(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