From 30913f26b675803940d8cca424f1f49b93822930 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rn=20Friedrich=20Dreyer?= <jfd@butonic.de>
Date: Wed, 21 Oct 2020 13:33:27 +0200
Subject: [PATCH] fix etag propagation in ocis driver
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Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Jörn Friedrich Dreyer <jfd@butonic.de>
---
 .../unreleased/ocis-fix-etag-propagation.md   |  5 +++
 pkg/storage/fs/ocis/tree.go                   | 35 +++++++++++--------
 2 files changed, 25 insertions(+), 15 deletions(-)
 create mode 100644 changelog/unreleased/ocis-fix-etag-propagation.md

diff --git a/changelog/unreleased/ocis-fix-etag-propagation.md b/changelog/unreleased/ocis-fix-etag-propagation.md
new file mode 100644
index 00000000000..e95f886d1fc
--- /dev/null
+++ b/changelog/unreleased/ocis-fix-etag-propagation.md
@@ -0,0 +1,5 @@
+Bugfix: Fix etag propagation in ocis driver
+
+We now use a new synctime timestamp instead of trying to read the mtime to avoid race conditions when the stat request happens too quickly.
+
+https://github.com/cs3org/reva/pull/1264
\ No newline at end of file
diff --git a/pkg/storage/fs/ocis/tree.go b/pkg/storage/fs/ocis/tree.go
index dd49c044cb4..1d1e56a7845 100644
--- a/pkg/storage/fs/ocis/tree.go
+++ b/pkg/storage/fs/ocis/tree.go
@@ -316,8 +316,6 @@ func (t *Tree) Propagate(ctx context.Context, n *Node) (err error) {
 	}
 	log := appctx.GetLogger(ctx)
 
-	nodePath := t.lu.toInternalPath(n.ID)
-
 	// is propagation enabled for the parent node?
 
 	var root *Node
@@ -325,12 +323,8 @@ func (t *Tree) Propagate(ctx context.Context, n *Node) (err error) {
 		return
 	}
 
-	var fi os.FileInfo
-	if fi, err = os.Stat(nodePath); err != nil {
-		return err
-	}
-
-	var b []byte
+	// use a sync time and don't rely on the mtime of the current node, as the stat might not change when a rename happened too quickly
+	sTime := time.Now().UTC()
 
 	for err == nil && n.ID != root.ID {
 		log.Debug().Interface("node", n).Msg("propagating")
@@ -355,22 +349,33 @@ func (t *Tree) Propagate(ctx context.Context, n *Node) (err error) {
 			switch {
 			case err != nil:
 				// missing attribute, or invalid format, overwrite
-				log.Error().Err(err).Interface("node", n).Msg("could not read tmtime attribute, overwriting")
+				log.Error().Err(err).
+					Interface("node", n).
+					Msg("could not read tmtime attribute, overwriting")
 				updateSyncTime = true
-			case tmTime.Before(fi.ModTime()):
-				log.Debug().Interface("node", n).Str("tmtime", string(b)).Str("mtime", fi.ModTime().UTC().Format(time.RFC3339Nano)).Msg("parent tmtime is older than node mtime, updating")
+			case tmTime.Before(sTime):
+				log.Debug().
+					Interface("node", n).
+					Time("tmtime", tmTime).
+					Time("stime", sTime).
+					Msg("parent tmtime is older than node mtime, updating")
 				updateSyncTime = true
 			default:
-				log.Debug().Interface("node", n).Str("tmtime", string(b)).Str("mtime", fi.ModTime().UTC().Format(time.RFC3339Nano)).Msg("parent tmtime is younger than node mtime, not updating")
+				log.Debug().
+					Interface("node", n).
+					Time("tmtime", tmTime).
+					Time("stime", sTime).
+					Dur("delta", sTime.Sub(tmTime)).
+					Msg("parent tmtime is younger than node mtime, not updating")
 			}
 
 			if updateSyncTime {
 				// update the tree time of the parent node
-				if err = n.SetTMTime(fi.ModTime()); err != nil {
-					log.Error().Err(err).Interface("node", n).Time("tmtime", fi.ModTime().UTC()).Msg("could not update tmtime of parent node")
+				if err = n.SetTMTime(sTime); err != nil {
+					log.Error().Err(err).Interface("node", n).Time("tmtime", sTime).Msg("could not update tmtime of parent node")
 					return
 				}
-				log.Debug().Interface("node", n).Time("tmtime", fi.ModTime().UTC()).Msg("updated tmtime of parent node")
+				log.Debug().Interface("node", n).Time("tmtime", sTime).Msg("updated tmtime of parent node")
 			}
 
 			if err := n.UnsetTempEtag(); err != nil {