From 161a039f8088bf8ce7000d8175e3793219525179 Mon Sep 17 00:00:00 2001
From: Kotresh HR <[email protected]>
Date: Thu, 28 Mar 2019 07:17:16 -0400
Subject: [PATCH 50/52] geo-rep: Fix syncing multiple rename of symlink

Problem:
Geo-rep fails to sync rename of symlink if it's
renamed multiple times if creation and rename
happened successively

Worker crash at slave:
Traceback (most recent call last):
  File "/usr/libexec/glusterfs/python/syncdaemon/repce.py",  in worker
    res = getattr(self.obj, rmeth)(*in_data[2:])
  File "/usr/libexec/glusterfs/python/syncdaemon/resource.py", in entry_ops
    [ESTALE, EINVAL, EBUSY])
  File "/usr/libexec/glusterfs/python/syncdaemon/syncdutils.py", in errno_wrap
    return call(*arg)
  File "/usr/libexec/glusterfs/python/syncdaemon/libcxattr.py", in lsetxattr
    cls.raise_oserr()
  File "/usr/libexec/glusterfs/python/syncdaemon/libcxattr.py", in raise_oserr
    raise OSError(errn, os.strerror(errn))
OSError: [Errno 12] Cannot allocate memory

Geo-rep Behaviour:
1. SYMLINK doesn't record target path in changelog.
   So while syncing SYMLINK, readlink is done on
   master to get target path.

2. Geo-rep will create destination if source is not
   present while syncing RENAME. Hence while syncing
   RENAME of SYMLINK, target path is collected from
   destination.

Cause:
If symlink is created and renamed multiple times, creation of
symlink is ignored, as it's no longer present on master at
that path. While symlink is renamed multiple times at master,
when syncing first RENAME of SYMLINK, both source and destination
is not present, hence target path is not known.  In this case,
while creating destination directly at slave,  regular file
attributes were encoded into blob instead of symlink,
causing failure in gfid-access translator while decoding
blob.

Solution:
While syncing of RENAME of SYMLINK, when target is not known
and when src and destination is not present on the master,
don't create destination. Ignore the rename. It's ok to ignore.
If it's unliked, it's fine.  If it's renamed to something else,
it will be synced then.

Backport of:
> Patch: https://review.gluster.org/22438
> Change-Id: Ibdfa495513b7c05b5370ab0b89c69a6802338d87
> BUG: 1693648
> Signed-off-by: Kotresh HR <[email protected]>

Change-Id: Ibdfa495513b7c05b5370ab0b89c69a6802338d87
fixes: bz#1670429
Signed-off-by: Kotresh HR <[email protected]>
Reviewed-on: https://code.engineering.redhat.com/gerrit/167122
Tested-by: RHGS Build Bot <[email protected]>
Reviewed-by: Sunil Kumar Heggodu Gopala Acharya <[email protected]>
---
 geo-replication/syncdaemon/resource.py   | 23 ++++++++++++++---------
 tests/00-geo-rep/georep-basic-dr-rsync.t |  1 +
 tests/geo-rep.rc                         | 12 ++++++++++++
 3 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/geo-replication/syncdaemon/resource.py b/geo-replication/syncdaemon/resource.py
index a2d0b16..c290d86 100644
--- a/geo-replication/syncdaemon/resource.py
+++ b/geo-replication/syncdaemon/resource.py
@@ -625,15 +625,20 @@ class Server(object):
                 # exist with different gfid.
                 if not matching_disk_gfid(gfid, entry):
                     if e['stat'] and not stat.S_ISDIR(e['stat']['mode']):
-                        if stat.S_ISLNK(e['stat']['mode']) and \
-                           e['link'] is not None:
-                            st1 = lstat(en)
-                            if isinstance(st1, int):
-                                (pg, bname) = entry2pb(en)
-                                blob = entry_pack_symlink(cls, gfid, bname,
-                                                          e['link'], e['stat'])
-                            elif not matching_disk_gfid(gfid, en):
-                                collect_failure(e, EEXIST, uid, gid, True)
+                        if stat.S_ISLNK(e['stat']['mode']):
+                            # src is not present, so don't sync symlink as
+                            # we don't know target. It's ok to ignore. If
+                            # it's unliked, it's fine. If it's renamed to
+                            # something else, it will be synced then.
+                            if e['link'] is not None:
+                                st1 = lstat(en)
+                                if isinstance(st1, int):
+                                    (pg, bname) = entry2pb(en)
+                                    blob = entry_pack_symlink(cls, gfid, bname,
+                                                              e['link'],
+                                                              e['stat'])
+                                elif not matching_disk_gfid(gfid, en):
+                                    collect_failure(e, EEXIST, uid, gid, True)
                         else:
                             slink = os.path.join(pfx, gfid)
                             st = lstat(slink)
diff --git a/tests/00-geo-rep/georep-basic-dr-rsync.t b/tests/00-geo-rep/georep-basic-dr-rsync.t
index 4a03930..8b64370 100644
--- a/tests/00-geo-rep/georep-basic-dr-rsync.t
+++ b/tests/00-geo-rep/georep-basic-dr-rsync.t
@@ -110,6 +110,7 @@ EXPECT_WITHIN $GEO_REP_TIMEOUT 0 chown_file_ok ${slave_mnt}/hybrid_chown_f1
 #Check History Crawl.
 TEST $GEOREP_CLI $master $slave stop
 TEST create_data "history"
+TEST create_rename_symlink_case
 TEST $GEOREP_CLI $master $slave start
 EXPECT_WITHIN $GEO_REP_TIMEOUT  2 check_status_num_rows "Active"
 EXPECT_WITHIN $GEO_REP_TIMEOUT  2 check_status_num_rows "Passive"
diff --git a/tests/geo-rep.rc b/tests/geo-rep.rc
index 396b4c4..d723129 100644
--- a/tests/geo-rep.rc
+++ b/tests/geo-rep.rc
@@ -19,6 +19,18 @@ function check_common_secret_file()
     echo $?
 }
 
+function create_rename_symlink_case()
+{
+    mkdir ${mastermnt}/MUL_REN_SYMLINK
+    cd ${mastermnt}/MUL_REN_SYMLINK
+    mkdir sym_dir1
+    ln -s "sym_dir1" sym1
+    mv sym1 sym2
+    mv sym2 sym3
+    mv sym3 sym4
+    cd -
+}
+
 function create_data()
 {
     prefix=$1
-- 
1.8.3.1