tier/ctr: Correcting rename logic

Problem: When a file with old_file_name and GFID_1 is renamed with a new_file_name
which already exists and with GFID_2, this is what happens in linux internaly.
   a. "new_file_name" is unlinked for GFID_2
   b. a hardlink "new_file_name" is created to GFID_1
   c. "old_file_name" hardlink is unlinked for GFID_2.
Well this is all internal to linux, and gluster just issues a rename system call
at POSIX layer. But CTR Xlator doesn't delete the entries corresponding to the
"new_file_name" and GFID_2. Thus leaving the stale entry in the DB.
The following are the implications.
a. Promotion are tried on these stale entries which will fail and show
false results in the status of migration,
b. GFID_2 Files with 2 hardlinks, which will have only one hardlink
after the rename will not be promoted or demoted as the DB shows 2 entries.

Solution: Delete the older database entry for the replaced hardlink

Backport of http://review.gluster.org/12711

> Change-Id: I4eafa0872253e29ff1f0bec4283bcfc579ecf0e2
> BUG: 1284090
> Signed-off-by: Joseph Fernandes <josferna@redhat.com>
> Reviewed-on: http://review.gluster.org/12711
> Tested-by: NetBSD Build System <jenkins@build.gluster.org>
> Tested-by: Gluster Build System <jenkins@build.gluster.com>
> Reviewed-by: Dan Lambright <dlambrig@redhat.com>
> Tested-by: Dan Lambright <dlambrig@redhat.com>
Signed-off-by: Joseph Fernandes <josferna@redhat.com>

Change-Id: Ic35348303ec21f9bd19f20a48f3141449349668b
BUG: 1285688
Reviewed-on: http://review.gluster.org/12762
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Dan Lambright <dlambrig@redhat.com>
Tested-by: Dan Lambright <dlambrig@redhat.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/tests/basic/tier/ctr-rename-overwrite.t b/tests/basic/tier/ctr-rename-overwrite.t
new file mode 100755
index 00000000000..a1d5af03a39
--- /dev/null
+++ b/tests/basic/tier/ctr-rename-overwrite.t
@@ -0,0 +1,49 @@
+#!/bin/bash
+
+. $(dirname $0)/../../include.rc
+. $(dirname $0)/../../volume.rc
+. $(dirname $0)/../../tier.rc
+
+LAST_BRICK=1
+CACHE_BRICK_FIRST=4
+CACHE_BRICK_LAST=5
+
+DEMOTE_FREQ=5
+PROMOTE_FREQ=5
+
+cleanup
+
+# Start glusterd
+TEST glusterd
+TEST pidof glusterd
+
+# Set-up tier cluster
+TEST $CLI volume create $V0 replica 2 $H0:$B0/${V0}{0..$LAST_BRICK}
+TEST $CLI volume start $V0
+TEST $CLI volume attach-tier $V0 replica 2 $H0:$B0/${V0}$CACHE_BRICK_FIRST $H0:$B0/${V0}$CACHE_BRICK_LAST
+
+TEST $CLI volume set $V0 cluster.tier-demote-frequency $DEMOTE_FREQ
+TEST $CLI volume set $V0 cluster.tier-promote-frequency $PROMOTE_FREQ
+
+# Start and mount the volume after enabling CTR
+TEST $CLI volume set $V0 features.ctr-enabled on
+TEST $GFS --volfile-id=/$V0 --volfile-server=$H0 $M0;
+
+# create two files
+echo "hello world" > $M0/file1
+echo "hello world" > $M0/file2
+
+# db in hot brick shows 4 record. 2 for file1 and 2 for file2
+ENTRY_COUNT=$(echo "select * from gf_file_tb; select * from gf_flink_tb;" | \
+        sqlite3 $B0/${V0}5/.glusterfs/${V0}5.db | wc -l )
+TEST [ $ENTRY_COUNT -eq 4 ]
+
+#overwrite file2 with file1
+mv -f $M0/file1 $M0/file2
+
+# Now the db in hot tier should have only 2 records for file1.
+ENTRY_COUNT=$(echo "select * from gf_file_tb; select * from gf_flink_tb;" | \
+        sqlite3 $B0/${V0}5/.glusterfs/${V0}5.db | wc -l )
+TEST [ $ENTRY_COUNT -eq 2 ]
+
+cleanup