linux-kernel - [PATCH v5 15/39] iomap: Support large pages in invalidatepage

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Message-Id: <20200529025824.32296-16-willy@infradead.org>
Date:   Thu, 28 May 2020 19:58:00 -0700
From:   Matthew Wilcox <willy@...radead.org>
To:     linux-fsdevel@...r.kernel.org
Cc:     "Matthew Wilcox (Oracle)" <willy@...radead.org>,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: [PATCH v5 15/39] iomap: Support large pages in invalidatepage

From: "Matthew Wilcox (Oracle)" <willy@...radead.org>

If we're punching a hole in a large page, we need to remove the per-page
iomap data, but not clear the dirty bit from the page, so separate the
two conditions.

Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
---
 fs/iomap/buffered-io.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 423ffc9d4a97..23eaaf1de906 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -493,17 +493,21 @@ EXPORT_SYMBOL_GPL(iomap_releasepage);
 void
 iomap_invalidatepage(struct page *page, unsigned int offset, unsigned int len)
 {
+	bool full_page = (offset == 0) && (len == thp_size(page));
 	trace_iomap_invalidatepage(page->mapping->host, offset, len);
 
 	/*
 	 * If we are invalidating the entire page, clear the dirty state from it
 	 * and release it to avoid unnecessary buildup of the LRU.
 	 */
-	if (offset == 0 && len == PAGE_SIZE) {
+	if (full_page) {
 		WARN_ON_ONCE(PageWriteback(page));
 		cancel_dirty_page(page);
-		iomap_page_release(page);
 	}
+
+	/* Punching a hole in a THP requires releasing the iop */
+	if (full_page || thp_order(page) > 0)
+		iomap_page_release(page);
 }
 EXPORT_SYMBOL_GPL(iomap_invalidatepage);
 
-- 
2.26.2