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From:   Dominique Martinet <asmadeus@codewreck.org>
Date:   Wed, 03 May 2023 16:49:25 +0900
Subject: [PATCH v2 1/5] 9p: fix ignored return value in v9fs_dir_release
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Message-Id: <20230427-scan-build-v2-1-bb96a6e6a33b@codewreck.org>
References: <20230427-scan-build-v2-0-bb96a6e6a33b@codewreck.org>
In-Reply-To: <20230427-scan-build-v2-0-bb96a6e6a33b@codewreck.org>
To:     Eric Van Hensbergen <ericvh@gmail.com>,
        Latchesar Ionkov <lucho@ionkov.net>,
        Christian Schoenebeck <linux_oss@crudebyte.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
Cc:     Simon Horman <simon.horman@corigine.com>, v9fs@lists.linux.dev,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        Dominique Martinet <asmadeus@codewreck.org>
Precedence: bulk

retval from filemap_fdatawrite was immediately overwritten by the
following p9_fid_put: preserve any error in fdatawrite if there
was any first.

This fixes the following scan-build warning:
fs/9p/vfs_dir.c:220:4: warning: Value stored to 'retval' is never read [deadcode.DeadStores]
                        retval = filemap_fdatawrite(inode->i_mapping);
                        ^        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fixes: d9bc0d11e33b ("fs/9p: Consolidate file operations and add readahead and writeback")
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
---
 fs/9p/vfs_dir.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/9p/vfs_dir.c b/fs/9p/vfs_dir.c
index 289b58cb896e..54bb99f12390 100644
--- a/fs/9p/vfs_dir.c
+++ b/fs/9p/vfs_dir.c
@@ -209,7 +209,7 @@ int v9fs_dir_release(struct inode *inode, struct file *filp)
 	struct p9_fid *fid;
 	__le32 version;
 	loff_t i_size;
-	int retval = 0;
+	int retval = 0, put_err;
 
 	fid = filp->private_data;
 	p9_debug(P9_DEBUG_VFS, "inode: %p filp: %p fid: %d\n",
@@ -222,7 +222,8 @@ int v9fs_dir_release(struct inode *inode, struct file *filp)
 		spin_lock(&inode->i_lock);
 		hlist_del(&fid->ilist);
 		spin_unlock(&inode->i_lock);
-		retval = p9_fid_put(fid);
+		put_err = p9_fid_put(fid);
+		retval = retval < 0 ? retval : put_err;
 	}
 
 	if ((filp->f_mode & FMODE_WRITE)) {

-- 
2.39.2