git: 56b64e28e11c - main - nfscl: Do not flush when a write delegation is held

The branch main has been updated by rmacklem:

URL: https://cgit.FreeBSD.org/src/commit/?id=56b64e28e11ce4f474b5d352ae3c0e218c345948

commit 56b64e28e11ce4f474b5d352ae3c0e218c345948
Author:     Rick Macklem <rmacklem@FreeBSD.org>
AuthorDate: 2022-06-02 19:11:55 +0000
Commit:     Rick Macklem <rmacklem@FreeBSD.org>
CommitDate: 2022-06-02 19:11:55 +0000

    nfscl: Do not flush when a write delegation is held
    
    When a NFSv4 byte range write lock is unlocked, all
    data modifications need to be flushed to the server
    to satisfy the coherency requirements for byte range
    locking.  However, if a write delegation for the
    file is held by the client, flushing is not required,
    since no other NFSv4 client can have the file NFSv4
    Opened.
    
    Found by inspection as suggested by a similar change
    that was done to the Linux NFSv4 client.
---
 sys/fs/nfsclient/nfs_clstate.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/sys/fs/nfsclient/nfs_clstate.c b/sys/fs/nfsclient/nfs_clstate.c
index 3b65828d5958..7a0d323a788a 100644
--- a/sys/fs/nfsclient/nfs_clstate.c
+++ b/sys/fs/nfsclient/nfs_clstate.c
@@ -1468,6 +1468,12 @@ nfscl_checkwritelocked(vnode_t vp, struct flock *fl,
 	 */
 	dp = nfscl_finddeleg(clp, np->n_fhp->nfh_fh, np->n_fhp->nfh_len);
 	if (dp != NULL) {
+		/* No need to flush if it is a write delegation. */
+		if ((dp->nfsdl_flags & NFSCLDL_WRITE) != 0) {
+			nfscl_clrelease(clp);
+			NFSUNLOCKCLSTATE();
+			return (0);
+		}
 		LIST_FOREACH(lp, &dp->nfsdl_lock, nfsl_list) {
 			if (!NFSBCMP(lp->nfsl_owner, own,
 			    NFSV4CL_LOCKNAMELEN))