[PATCH 4.14 107/195] NFS: commit direct writes even if they fail partially

From: Greg Kroah-Hartman
Date: Thu Feb 15 2018 - 10:34:29 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: J. Bruce Fields <bfields@xxxxxxxxxx>

commit 1b8d97b0a837beaf48a8449955b52c650a7114b4 upstream.

If some of the WRITE calls making up an O_DIRECT write syscall fail,
we neglect to commit, even if some of the WRITEs succeed.

We also depend on the commit code to free the reference count on the
nfs_page taken in the "if (request_commit)" case at the end of
nfs_direct_write_completion(). The problem was originally noticed
because ENOSPC's encountered partway through a write would result in a
closed file being sillyrenamed when it should have been unlinked.

Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/nfs/direct.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -775,10 +775,8 @@ static void nfs_direct_write_completion(

spin_lock(&dreq->lock);

- if (test_bit(NFS_IOHDR_ERROR, &hdr->flags)) {
- dreq->flags = 0;
+ if (test_bit(NFS_IOHDR_ERROR, &hdr->flags))
dreq->error = hdr->error;
- }
if (dreq->error == 0) {
nfs_direct_good_bytes(dreq, hdr);
if (nfs_write_need_commit(hdr)) {