From: Chuck Lever chuck.lever@oracle.com
[ Upstream commit 644c9f40cf71969f29add32f32349e71d4995c0b ]
If a write delegation isn't available, the Linux NFS client uses a zero-stateid when performing a SETATTR.
NFSv4.0 provides no mechanism for an NFS server to match such a request to a particular client. It recalls all delegations for that file, even delegations held by the client issuing the request. If that client happens to hold a read delegation, the server will recall it immediately, resulting in an NFS4ERR_DELAY/CB_RECALL/ DELEGRETURN sequence.
Optimize out this pipeline bubble by having the client return any delegations it may hold on a file before it issues a SETATTR(zero-stateid) on that file.
Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfs/nfs4proc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 7f337188a2829..08b1fb0a9225a 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -3272,8 +3272,10 @@ static int _nfs4_do_setattr(struct inode *inode,
/* Servers should only apply open mode checks for file size changes */ truncate = (arg->iap->ia_valid & ATTR_SIZE) ? true : false; - if (!truncate) + if (!truncate) { + nfs4_inode_make_writeable(inode); goto zero_stateid; + }
if (nfs4_copy_delegation_stateid(inode, FMODE_WRITE, &arg->stateid, &delegation_cred)) { /* Use that stateid */