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authorChuck Lever <chuck.lever@oracle.com>2020-09-04 17:39:12 -0400
committerTrond Myklebust <trond.myklebust@hammerspace.com>2020-09-05 10:39:41 -0400
commit644c9f40cf71969f29add32f32349e71d4995c0b (patch)
treeb4055becff17fe31230bf1a6be2e20e5759eb6fb /fs/nfs
parent3d7a9520f0c3e6a68b6de8c5812fc8b6d7a52626 (diff)
NFS: Zero-stateid SETATTR should first return delegation
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>
Diffstat (limited to 'fs/nfs')
-rw-r--r--fs/nfs/nfs4proc.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 4a6cfb497103..3e824110b470 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -3293,8 +3293,10 @@ 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 */