linux-kernel - [PATCH v3 2/4] iomap: move iter revert case out of the unwritten branch

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Message-ID: <20250812091538.2004295-3-alexjlzheng@tencent.com>
Date: Tue, 12 Aug 2025 17:15:36 +0800
From: alexjlzheng@...il.com
To: brauner@...nel.org,
	djwong@...nel.org
Cc: linux-xfs@...r.kernel.org,
	linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	yi.zhang@...wei.com,
	Jinliang Zheng <alexjlzheng@...cent.com>
Subject: [PATCH v3 2/4] iomap: move iter revert case out of the unwritten branch

From: Jinliang Zheng <alexjlzheng@...cent.com>

The commit e1f453d4336d ("iomap: do some small logical cleanup in
buffered write") merged iomap_write_failed() and iov_iter_revert()
into the branch with written == 0. Because, at the time,
iomap_write_end() could never return a partial write length.

In the subsequent patch, iomap_write_end() will be modified to allow
to return block-aligned partial write length (partial write length
here is relative to the folio-sized write), which violated the above
patch's assumption.

This patch moves it back out to prepare for the subsequent patches.

Signed-off-by: Jinliang Zheng <alexjlzheng@...cent.com>
---
 fs/iomap/buffered-io.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 0c38333933c6..109c3bad6ccf 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1019,6 +1019,11 @@ static int iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i,
 
 		if (old_size < pos)
 			pagecache_isize_extended(iter->inode, old_size, pos);
+		if (written < bytes)
+			iomap_write_failed(iter->inode, pos + written,
+					   bytes - written);
+		if (unlikely(copied != written))
+			iov_iter_revert(i, copied - written);
 
 		cond_resched();
 		if (unlikely(written == 0)) {
@@ -1028,9 +1033,6 @@ static int iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i,
 			 * halfway through, might be a race with munmap,
 			 * might be severe memory pressure.
 			 */
-			iomap_write_failed(iter->inode, pos, bytes);
-			iov_iter_revert(i, copied);
-
 			if (chunk > PAGE_SIZE)
 				chunk /= 2;
 			if (copied) {
-- 
2.49.0