From d32ddfeb559342e89a4d06b1df4e7e5e96df3762 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Mon, 27 Oct 2025 13:52:28 -0400 Subject: [PATCH] nfs/localio: Ensure DIO WRITE's IO on stable storage upon completion LOCALIO's misaligned DIO WRITE support requires synchronous IO for any misaligned head and/or tail that are issued using buffered IO. In addition, it is important that the O_DIRECT middle be on stable storage upon its completion via AIO. Otherwise, a misaligned DIO WRITE could mix buffered IO for the head/tail and direct IO for the DIO-aligned middle -- which could lead to problems associated with deferred writes to stable storage (such as out of order partial completions causing incorrect advancement of the file's offset, etc). Fixes: c817248fc831 ("nfs/localio: add proper O_DIRECT support for READ and WRITE") Signed-off-by: Mike Snitzer Signed-off-by: Anna Schumaker --- fs/nfs/localio.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/fs/nfs/localio.c b/fs/nfs/localio.c index 9c205f8b5e59c..839dbda0b3704 100644 --- a/fs/nfs/localio.c +++ b/fs/nfs/localio.c @@ -485,8 +485,12 @@ nfs_local_iters_init(struct nfs_local_kiocb *iocb, int rw) struct nfs_local_dio local_dio; if (nfs_is_local_dio_possible(iocb, rw, len, &local_dio) && - nfs_local_iters_setup_dio(iocb, rw, v, len, &local_dio) != 0) + nfs_local_iters_setup_dio(iocb, rw, v, len, &local_dio) != 0) { + /* Ensure DIO WRITE's IO on stable storage upon completion */ + if (rw == ITER_SOURCE) + iocb->kiocb.ki_flags |= IOCB_DSYNC|IOCB_SYNC; return; /* is DIO-aligned */ + } } /* Use buffered IO */ -- 2.47.3