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From:   Matthew Wilcox <willy@infradead.org>
To:     linux-fsdevel@vger.kernel.org
Cc:     "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH v4 18/36] iomap: Handle tail pages in iomap_page_mkwrite
Date:   Fri, 15 May 2020 06:16:38 -0700
Message-Id: <20200515131656.12890-19-willy@infradead.org>
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From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

iomap_page_mkwrite() can be called with a tail page.  If we are,
operate on the head page, since we're treating the entire thing as a
single unit and the whole page is dirtied at the same time.

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

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 782757258a28..c9636d55a4be 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1060,7 +1060,7 @@ iomap_page_mkwrite_actor(struct inode *inode, loff_t pos, loff_t length,
 
 vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops)
 {
-	struct page *page = vmf->page;
+	struct page *page = compound_head(vmf->page);
 	struct inode *inode = file_inode(vmf->vma->vm_file);
 	unsigned long length;
 	loff_t offset;
-- 
2.26.2