[PATCHES] Issue fsync for SMB2 FLUSH asynchronously

[Christof Schmitt]

From 38b49fd2527c161980afbecd80820debafda8f46 Mon Sep 17 00:00:00 2001
From: Christof Schmitt <cs at samba.org>
Date: Wed, 11 Nov 2015 13:28:09 -0700
Subject: [PATCH 1/2] selftest: Use strict sync = yes

This enables the codepaths calling fsync for FLUSH requests during
selftest.

Signed-off-by: Christof Schmitt <cs at samba.org>
---
 selftest/target/Samba3.pm |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/selftest/target/Samba3.pm b/selftest/target/Samba3.pm
index 4b7882b..1c54dae 100755
--- a/selftest/target/Samba3.pm
+++ b/selftest/target/Samba3.pm
@@ -1331,6 +1331,7 @@ sub provision($$$$$$$$)
 	create mask = 755
 	dos filemode = yes
 	strict rename = yes
+	strict sync = yes
 	vfs objects = acl_xattr fake_acls xattr_tdb streams_depot
 
 	printing = vlp
-- 
1.7.1


From 4762b67740770f1ba43e78349c8d1f48857b55dd Mon Sep 17 00:00:00 2001
From: Christof Schmitt <cs at samba.org>
Date: Wed, 11 Nov 2015 13:31:15 -0700
Subject: [PATCH 2/2] smbd: Issue fsync for SMB2 FLUSH asynchronously

SMB2 FLUSH mainly calls fsync and there is already code in place to
handle fsync asynchronously, so use the asynchronous code path for SMB2
FLUSH. This avoids a SMB2 FLUSH stalling other requests processing.

Signed-off-by: Christof Schmitt <cs at samba.org>
---
 source3/smbd/smb2_flush.c |   39 +++++++++++++++++++++++++++++++--------
 1 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/source3/smbd/smb2_flush.c b/source3/smbd/smb2_flush.c
index 04a8710..7af6aab 100644
--- a/source3/smbd/smb2_flush.c
+++ b/source3/smbd/smb2_flush.c
@@ -110,14 +110,15 @@ struct smbd_smb2_flush_state {
 	struct smbd_smb2_request *smb2req;
 };
 
+static void smbd_smb2_flush_done(struct tevent_req *subreq);
+
 static struct tevent_req *smbd_smb2_flush_send(TALLOC_CTX *mem_ctx,
 					       struct tevent_context *ev,
 					       struct smbd_smb2_request *smb2req,
 					       struct files_struct *fsp)
 {
-	struct tevent_req *req;
+	struct tevent_req *req, *subreq;
 	struct smbd_smb2_flush_state *state;
-	NTSTATUS status;
 	struct smb_request *smbreq;
 
 	req = tevent_req_create(mem_ctx, &state,
@@ -145,18 +146,40 @@ static struct tevent_req *smbd_smb2_flush_send(TALLOC_CTX *mem_ctx,
 		return tevent_req_post(req, ev);
 	}
 
-	status = sync_file(smbreq->conn, fsp, true);
-	if (!NT_STATUS_IS_OK(status)) {
-		DEBUG(5,("smbd_smb2_flush: sync_file for %s returned %s\n",
-			 fsp_str_dbg(fsp), nt_errstr(status)));
-		tevent_req_nterror(req, status);
-		return tevent_req_post(req, ev);
+	if (lp_strict_sync(SNUM(smbreq->conn))) {
+		int ret = flush_write_cache(fsp, SAMBA_SYNC_FLUSH);
+		if (ret == -1) {
+			tevent_req_nterror(req,  map_nt_error_from_unix(errno));
+			return tevent_req_post(req, ev);
+		}
+
+		subreq = SMB_VFS_FSYNC_SEND(state, ev, fsp);
+		if (tevent_req_nomem(subreq, req)) {
+			return tevent_req_post(req, ev);
+		}
+
+		tevent_req_set_callback(subreq, smbd_smb2_flush_done, req);
 	}
 
 	tevent_req_done(req);
 	return tevent_req_post(req, ev);
 }
 
+static void smbd_smb2_flush_done(struct tevent_req *subreq)
+{
+	struct tevent_req *req = tevent_req_callback_data(
+		subreq, struct tevent_req);
+	int ret, err;
+
+	ret = SMB_VFS_FSYNC_RECV(subreq, &err);
+	TALLOC_FREE(subreq);
+	if (ret == -1) {
+		tevent_req_error(req, err);
+		return;
+	}
+	tevent_req_done(req);
+}
+
 static NTSTATUS smbd_smb2_flush_recv(struct tevent_req *req)
 {
 	NTSTATUS status;
-- 
1.7.1