linux-kernel - [PATCH v2 1/9] iomap: Fix misplaced page flushing

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Date:   Fri, 11 Sep 2020 00:46:59 +0100
From:   "Matthew Wilcox (Oracle)" <willy@...radead.org>
To:     linux-xfs@...r.kernel.org, linux-fsdevel@...r.kernel.org
Cc:     "Matthew Wilcox (Oracle)" <willy@...radead.org>,
        "Darrick J . Wong" <darrick.wong@...cle.com>,
        Christoph Hellwig <hch@...radead.org>,
        linux-nvdimm@...ts.01.org, linux-kernel@...r.kernel.org,
        Dave Kleikamp <shaggy@...nel.org>,
        jfs-discussion@...ts.sourceforge.net,
        Dave Chinner <dchinner@...hat.com>,
        Christoph Hellwig <hch@....de>
Subject: [PATCH v2 1/9] iomap: Fix misplaced page flushing

If iomap_unshare_actor() unshares to an inline iomap, the page was
not being flushed.  block_write_end() and __iomap_write_end() already
contain flushes, so adding it to iomap_write_end_inline() seems like
the best place.  That means we can remove it from iomap_write_actor().

Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
Reviewed-by: Dave Chinner <dchinner@...hat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@...cle.com>
Reviewed-by: Christoph Hellwig <hch@....de>
---
 fs/iomap/buffered-io.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 897ab9a26a74..d81a9a86c5aa 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -717,6 +717,7 @@ iomap_write_end_inline(struct inode *inode, struct page *page,
 	WARN_ON_ONCE(!PageUptodate(page));
 	BUG_ON(pos + copied > PAGE_SIZE - offset_in_page(iomap->inline_data));
 
+	flush_dcache_page(page);
 	addr = kmap_atomic(page);
 	memcpy(iomap->inline_data + pos, addr + pos, copied);
 	kunmap_atomic(addr);
@@ -810,8 +811,6 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 
 		copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes);
 
-		flush_dcache_page(page);
-
 		status = iomap_write_end(inode, pos, bytes, copied, page, iomap,
 				srcmap);
 		if (unlikely(status < 0))
-- 
2.28.0