fusefs: Handle ENOSYS for all remaining opcodes

For many FUSE opcodes, an error of ENOSYS has special meaning.  fusefs
already handled some of those; this commit adds handling for the remainder:

* FUSE_FSYNC, FUSE_FSYNCDIR: ENOSYS means "success, and automatically return
  success without calling the daemon from now on"
* All extattr operations: ENOSYS means "fail EOPNOTSUPP, and automatically
  do it without calling the daemon from now on"

PR:		236557
Sponsored by:	The FreeBSD Foundation

1 files changed, 10 insertions, 0 deletions

diff --git a/sys/fs/fuse/fuse_internal.c b/sys/fs/fuse/fuse_internal.c
index f30e8fe17681..935d049f3ba3 100644
--- a/sys/fs/fuse/fuse_internal.c
+++ b/sys/fs/fuse/fuse_internal.c
@@ -259,6 +259,7 @@ fuse_internal_fsync(struct vnode *vp,
 	struct fuse_dispatcher fdi;
 	struct fuse_filehandle *fufh;
 	struct fuse_vnode_data *fvdat = VTOFUD(vp);
+	struct mount *mp = vnode_mount(vp);
 	int op = FUSE_FSYNC;
 	int err = 0;
 
@@ -269,6 +270,9 @@ fuse_internal_fsync(struct vnode *vp,
 	if (vnode_isdir(vp))
 		op = FUSE_FSYNCDIR;
 
+	if (!fsess_isimpl(mp, op))
+		return 0;
+
 	fdisp_init(&fdi, sizeof(*ffsi));
 	/*
 	 * fsync every open file handle for this file, because we can't be sure
@@ -293,6 +297,12 @@ fuse_internal_fsync(struct vnode *vp,
 				fuse_internal_fsync_callback);
 			fuse_insert_message(fdi.tick);
 		}
+		if (err == ENOSYS) {
+			/* ENOSYS means "success, and don't call again" */
+			fsess_set_notimpl(mp, op);
+			err = 0;
+			break;
+		}
 	}
 	fdisp_destroy(&fdi);