[PATCH] nfs: fix refcount leak in nfs_direct_read_schedule_iovec()

[WenTao Liang <vulab@iscas.ac.cn>]

When nfs_direct_read_schedule_iovec() encounters an error after
get_dreq(dreq) increments the io_count but fails to start any I/O
(requested_bytes == 0), it falls through to the error path. That
path calls nfs_direct_req_release() to drop the I/O path’s kref,
but it never calls put_dreq() to balance the io_count. This leaves
the request’s io_count permanently elevated, a reference counting
violation that corrupts the teardown logic once the object is
freed via the remaining kref.

Fix the leak by calling put_dreq(dreq) before
nfs_direct_req_release() in the zero-bytes error path, so the
io_count is properly balanced.

Cc: stable@vger.kernel.org
Fixes: 65caafd0d214 ("SUNRPC reverting d03727b248d0 ("NFSv4 fix CLOSE not waiting for direct IO compeletion")")
Signed-off-by: WenTao Liang <vulab@iscas.ac.cn>
---
 fs/nfs/direct.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 48d89716193a..41a6cabb0592 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -400,6 +400,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
 	 */
 	if (requested_bytes == 0) {
 		inode_dio_end(inode);
+		put_dreq(dreq);
 		nfs_direct_req_release(dreq);
 		return result < 0 ? result : -EIO;
 	}
-- 
2.50.1 (Apple Git-155)