From: Marc Dionne <marc.dionne@auristor.com>
Date: Mon, 29 Jan 2024 09:49:18 +0000 (+0000)
Subject: netfs: Fix i_dio_count leak on DIO read past i_size
X-Git-Tag: v6.8-rc6~31^2~5
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=2147caaac7349698f2a392c5e2911a6861a09650;p=linux-2.6-block.git

netfs: Fix i_dio_count leak on DIO read past i_size

If netfs_begin_read gets a NETFS_DIO_READ request that begins
past i_size, it won't perform any i/o and just return 0.  This
will leak an increment to i_dio_count that is done at the top
of the function.

This can cause subsequent buffered read requests to block
indefinitely, waiting for a non existing dio operation to complete.

Add a inode_dio_end() for the NETFS_DIO_READ case, before returning.

Signed-off-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20240129094924.1221977-2-dhowells@redhat.com
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Jeff Layton <jlayton@kernel.org>
cc:  <linux-afs@lists.infradead.org>
cc:  <netfs@lists.linux.dev>
cc:  <linux-fsdevel@vger.kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---

diff --git a/fs/netfs/io.c b/fs/netfs/io.c
index e8ff1e61ce79..4261ad6c55b6 100644
--- a/fs/netfs/io.c
+++ b/fs/netfs/io.c
@@ -748,6 +748,8 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync)
 
 	if (!rreq->submitted) {
 		netfs_put_request(rreq, false, netfs_rreq_trace_put_no_submit);
+		if (rreq->origin == NETFS_DIO_READ)
+			inode_dio_end(rreq->inode);
 		ret = 0;
 		goto out;
 	}