From: Bart Van Assche <bvanassche@acm.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Joel Becker <jlbec@evilplan.org>,
linux-kernel@vger.kernel.org,
Bodo Stroesser <bostroesser@gmail.com>,
"Martin K . Petersen" <martin.petersen@oracle.com>,
Yanko Kaneti <yaneti@declera.com>,
Brendan Higgins <brendanhiggins@google.com>,
Bart Van Assche <bvanassche@acm.org>
Subject: [PATCH 2/4] configfs: Fix writing at a non-zero offset
Date: Fri, 23 Jul 2021 14:23:51 -0700 [thread overview]
Message-ID: <20210723212353.896343-3-bvanassche@acm.org> (raw)
In-Reply-To: <20210723212353.896343-1-bvanassche@acm.org>
Store data at the right offset when writing with a non-zero offset. I think
this patch fixes behavior introduced in the initial configfs commit. From a
source code comment in the initial configfs commit: "There is no easy way
for us to know if userspace is only doing a partial write, so we don't
support them."
Cc: Bodo Stroesser <bostroesser@gmail.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Yanko Kaneti <yaneti@declera.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
fs/configfs/file.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/fs/configfs/file.c b/fs/configfs/file.c
index 8121bb1b2121..3b2ddc2e5d42 100644
--- a/fs/configfs/file.c
+++ b/fs/configfs/file.c
@@ -226,14 +226,16 @@ static ssize_t configfs_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct configfs_buffer *buffer = file->private_data;
- ssize_t len;
+ int len, written = 0;
mutex_lock(&buffer->mutex);
len = fill_write_buffer(buffer, iocb->ki_pos, from);
if (len > 0)
- len = flush_write_buffer(file, buffer, len);
- if (len > 0)
- iocb->ki_pos += len;
+ written = flush_write_buffer(file, buffer, iocb->ki_pos + len);
+ if (written > 0) {
+ len = max_t(int, 0, written - iocb->ki_pos);
+ iocb->ki_pos = written;
+ }
mutex_unlock(&buffer->mutex);
return len;
}
next prev parent reply other threads:[~2021-07-23 21:24 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-23 21:23 [PATCH 0/4] Improve the configfs read and write iterators further Bart Van Assche
2021-07-23 21:23 ` [PATCH 1/4] configfs: Rework the overflow check in fill_write_buffer() Bart Van Assche
2021-07-23 21:23 ` Bart Van Assche [this message]
2021-07-26 14:58 ` [PATCH 2/4] configfs: Fix writing at a non-zero offset Bodo Stroesser
2021-07-26 16:26 ` Bart Van Assche
2021-07-26 21:13 ` Bodo Stroesser
2021-07-26 21:52 ` Bart Van Assche
2021-07-27 0:54 ` Bodo Stroesser
2021-07-27 3:17 ` Bart Van Assche
2021-07-27 7:27 ` Bodo Stroesser
2021-07-27 16:47 ` Bart Van Assche
2021-07-28 17:14 ` Bodo Stroesser
2021-07-28 17:55 ` Bart Van Assche
2021-07-23 21:23 ` [PATCH 3/4] kunit: Add support for suite initialization and cleanup Bart Van Assche
2021-07-27 21:26 ` Brendan Higgins
2021-07-29 3:33 ` Bart Van Assche
2021-07-23 21:23 ` [PATCH 4/4] configfs: Add unit tests Bart Van Assche
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