linux-kernel - [PATCH 01/11] fs: call file_{start,end}_write from __kernel

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Message-Id: <20200508092222.2097-2-hch@lst.de>
Date:   Fri,  8 May 2020 11:22:12 +0200
From:   Christoph Hellwig <hch@....de>
To:     Al Viro <viro@...iv.linux.org.uk>
Cc:     linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-security-module@...r.kernel.org
Subject: [PATCH 01/11] fs: call file_{start,end}_write from __kernel_write

We always need to take a reference on the file system we are writing
to.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 fs/read_write.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/read_write.c b/fs/read_write.c
index bbfa9b12b15eb..d5aaf3a4198b9 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -508,6 +508,7 @@ ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t
 	if (!(file->f_mode & FMODE_CAN_WRITE))
 		return -EINVAL;
 
+	file_start_write(file);
 	old_fs = get_fs();
 	set_fs(KERNEL_DS);
 	p = (__force const char __user *)buf;
@@ -520,6 +521,7 @@ ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t
 		add_wchar(current, ret);
 	}
 	inc_syscw(current);
+	file_end_write(file);
 	return ret;
 }
 EXPORT_SYMBOL(__kernel_write);
-- 
2.26.2