tier:unlink during migration

files deleted during promotion were not deleting as the
files are moving from hashed to non-hashed

On deleting a file that is undergoing promotion,
the unlink call is not sent to the dst file as the
hashed subvol == cached subvol. This causes
the file to reappear once the migration is complete.

This patch also fixes a problem with stale linkfile
deleting.

Backport of>
>Change-Id: I4b02a498218c9d8eeaa4556fa4219e91e7fa71e5
>BUG: 1282390
>Signed-off-by: Mohammed Rafi KC <rkavunga@redhat.com>
>Reviewed-on: http://review.gluster.org/12829
>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>

(cherry picked from commit b5de382afa8c5777e455c7a376fc4f1f01d782d1)

Change-Id: I951adb4d929926bcd646dd7574f7a2d41d57479d
BUG: 1282388
Signed-off-by: Mohammed Rafi KC <rkavunga@redhat.com>
Reviewed-on: http://review.gluster.org/12991
Smoke: Gluster Build System <jenkins@build.gluster.com>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Dan Lambright <dlambrig@redhat.com>

9 files changed, 573 insertions, 133 deletions

diff --git a/libglusterfs/src/glusterfs.h b/libglusterfs/src/glusterfs.h
index d5189917dea..c300bbbdf6d 100644
--- a/libglusterfs/src/glusterfs.h
+++ b/libglusterfs/src/glusterfs.h
@@ -240,6 +240,7 @@
 #define DHT_COMMITHASH_STR "commithash"
 
 #define DHT_SKIP_NON_LINKTO_UNLINK  "unlink-only-if-dht-linkto-file"
+#define TIER_SKIP_NON_LINKTO_UNLINK  "unlink-only-if-tier-linkto-file"
 #define DHT_SKIP_OPEN_FD_UNLINK     "dont-unlink-for-open-fd"
 #define DHT_IATT_IN_XDATA_KEY       "dht-get-iatt-in-xattr"
 
diff --git a/tests/basic/tier/unlink-during-migration.t b/tests/basic/tier/unlink-during-migration.t
new file mode 100755
index 00000000000..78887433ccb
--- /dev/null
+++ b/tests/basic/tier/unlink-during-migration.t
@@ -0,0 +1,91 @@
+#!/bin/bash
+
+. $(dirname $0)/../../include.rc
+. $(dirname $0)/../../volume.rc
+. $(dirname $0)/../../tier.rc
+
+
+DEMOTE_FREQ=5
+PROMOTE_FREQ=5
+
+function create_dist_rep_vol () {
+        mkdir $B0/cold
+        mkdir $B0/hot
+        TEST $CLI volume create $V0 replica 2 $H0:$B0/cold/${V0}{0..3}
+        TEST $CLI volume set $V0 performance.quick-read off
+        TEST $CLI volume set $V0 performance.io-cache off
+        TEST $CLI volume set $V0 features.ctr-enabled on
+        TEST $CLI volume start $V0
+}
+
+function attach_dist_rep_tier () {
+        TEST $CLI volume attach-tier $V0 replica 2 $H0:$B0/hot/${V0}{0..3}
+        TEST $CLI volume set $V0 cluster.tier-demote-frequency $DEMOTE_FREQ
+        TEST $CLI volume set $V0 cluster.tier-promote-frequency $PROMOTE_FREQ
+        TEST $CLI volume set $V0 cluster.read-freq-threshold 0
+        TEST $CLI volume set $V0 cluster.write-freq-threshold 0
+        TEST $CLI volume set $V0 cluster.tier-mode test
+}
+
+cleanup;
+
+#Basic checks
+TEST glusterd
+TEST pidof glusterd
+TEST $CLI volume info
+
+
+#Create and start a volume
+create_dist_rep_vol
+
+# Mount FUSE
+TEST glusterfs -s $H0 --volfile-id $V0 $M0
+
+# Create a large file (320MB), so that rebalance takes time
+TEST dd if=/dev/zero of=$M0/foo bs=64k count=5120
+
+# Get the path of the file on the cold tier
+CPATH=`find $B0/cold/ -name  foo`
+echo "File path on cold tier: "$CPATH
+
+#Now attach the tier
+attach_dist_rep_tier
+
+#Write into the file to promote it
+echo "good morning">>$M0/foo
+
+# Wait for the tier process to promote the file
+EXPECT_WITHIN $REBALANCE_TIMEOUT "yes" is_sticky_set $CPATH
+
+# Get the path of the file on the hot tier
+HPATH=`find $B0/hot/ -name  foo`
+
+echo "File path on hot tier: "$HPATH
+TEST rm -rf $M0/foo
+TEST ! stat $HPATH
+TEST ! stat $CPATH
+
+#unlink during demotion
+HPATH="";
+CPATH="";
+
+# Create a large file (320MB), so that rebalance takes time
+TEST dd if=/dev/zero of=$M0/foo1 bs=64k count=5120
+
+# Get the path of the file on the hot tier
+HPATH=`find $B0/hot/ -name  foo1`
+echo "File path on hot tier : "$HPATH
+
+EXPECT_WITHIN $REBALANCE_TIMEOUT "yes" is_sticky_set $HPATH
+
+# Get the path of the file on the cold tier
+CPATH=`find $B0/cold/ -name  foo1`
+echo "File path on cold tier : "$CPATH
+
+TEST rm -rf $M0/foo1
+
+TEST ! stat $HPATH
+TEST ! stat $CPATH
+
+cleanup;
+
diff --git a/xlators/cluster/dht/src/dht-common.c b/xlators/cluster/dht/src/dht-common.c
index 242e1798753..f80924e818b 100644
--- a/xlators/cluster/dht/src/dht-common.c
+++ b/xlators/cluster/dht/src/dht-common.c
@@ -1167,9 +1167,19 @@ dht_lookup_unlink_stale_linkto_cbk (call_frame_t *frame, void *cookie,
 int
 dht_fill_dict_to_avoid_unlink_of_migrating_file (dict_t *dict) {
 
-        int ret = 0;
+        int                      ret = 0;
+        xlator_t                *this           = NULL;
+        char                    *linktoskip_key = NULL;
+
+        this    = THIS;
+        GF_VALIDATE_OR_GOTO ("dht", this, err);
 
-        ret = dict_set_int32 (dict, DHT_SKIP_NON_LINKTO_UNLINK, 1);
+        if (dht_is_tier_xlator (this))
+                linktoskip_key = TIER_SKIP_NON_LINKTO_UNLINK;
+        else
+                linktoskip_key = DHT_SKIP_NON_LINKTO_UNLINK;
+
+        ret = dict_set_int32 (dict, linktoskip_key, 1);
 
         if (ret)
                 goto err;
@@ -2431,102 +2441,103 @@ err:
         return 0;
 }
 
-
 int
-dht_unlink_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
-                int op_ret, int op_errno, struct iatt *preparent,
-                struct iatt *postparent, dict_t *xdata)
+dht_unlink_linkfile_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
+                         int op_ret, int op_errno, struct iatt *preparent,
+                         struct iatt *postparent, dict_t *xdata)
 {
-        dht_local_t  *local = NULL;
-        call_frame_t *prev  = NULL;
+        dht_local_t     *local          = NULL;
+        call_frame_t    *prev           = NULL;
 
         local = frame->local;
         prev  = cookie;
 
         LOCK (&frame->lock);
         {
-                if (op_ret == -1) {
-                        local->op_ret   = -1;
+                if ((op_ret == -1) && !((op_errno == ENOENT) ||
+                                        (op_errno == ENOTCONN))) {
                         local->op_errno = op_errno;
                         gf_msg_debug (this->name, op_errno,
-                                      "Unlink: subvolume %s returned -1",
-                                       prev->this->name);
+                                      "Unlink link: subvolume %s"
+                                      " returned -1",
+                                      prev->this->name);
                         goto unlock;
                 }
 
                 local->op_ret = 0;
-
-                local->postparent = *postparent;
-                local->preparent = *preparent;
-
-                if (local->loc.parent) {
-                        dht_inode_ctx_time_update (local->loc.parent, this,
-                                                   &local->preparent, 0);
-                        dht_inode_ctx_time_update (local->loc.parent, this,
-                                                   &local->postparent, 1);
-                }
         }
 unlock:
         UNLOCK (&frame->lock);
 
+
         DHT_STACK_UNWIND (unlink, frame, local->op_ret, local->op_errno,
-                          &local->preparent, &local->postparent, NULL);
+                          &local->preparent, &local->postparent, xdata);
 
         return 0;
 }
 
-
 int
-dht_unlink_linkfile_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
-                         int op_ret, int op_errno, struct iatt *preparent,
-                         struct iatt *postparent, dict_t *xdata)
+dht_unlink_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
+                int op_ret, int op_errno, struct iatt *preparent,
+                struct iatt *postparent, dict_t *xdata)
 {
-        dht_local_t  *local = NULL;
-        call_frame_t *prev = NULL;
-
-        xlator_t *cached_subvol = NULL;
+        dht_local_t     *local          = NULL;
+        call_frame_t    *prev           = NULL;
+        xlator_t        *hashed_subvol  = NULL;
 
         local = frame->local;
         prev  = cookie;
 
         LOCK (&frame->lock);
         {
-                if ((op_ret == -1) && !((op_errno == ENOENT) ||
-                                        (op_errno == ENOTCONN))) {
-                        local->op_errno = op_errno;
+                if (op_ret == -1) {
+                        if (op_errno != ENOENT) {
+                                local->op_ret   = -1;
+                                local->op_errno = op_errno;
+                        } else {
+                                local->op_ret = 0;
+                        }
                         gf_msg_debug (this->name, op_errno,
-                                      "Unlink link: subvolume %s"
-                                      " returned -1",
-                                      prev->this->name);
+                                      "Unlink: subvolume %s returned -1",
+                                       prev->this->name);
                         goto unlock;
                 }
 
                 local->op_ret = 0;
+
+                local->postparent = *postparent;
+                local->preparent = *preparent;
+
+                if (local->loc.parent) {
+                        dht_inode_ctx_time_update (local->loc.parent, this,
+                                                   &local->preparent, 0);
+                        dht_inode_ctx_time_update (local->loc.parent, this,
+                                                   &local->postparent, 1);
+                }
         }
 unlock:
         UNLOCK (&frame->lock);
 
-        if (local->op_ret == -1)
-                goto err;
-
-        cached_subvol = dht_subvol_get_cached (this, local->loc.inode);
-        if (!cached_subvol) {
-                gf_msg_debug (this->name, 0,
-                              "no cached subvolume for path=%s",
-                              local->loc.path);
-                local->op_errno = EINVAL;
-                goto err;
+        if (!local->op_ret) {
+                hashed_subvol = dht_subvol_get_hashed (this, &local->loc);
+                if (hashed_subvol &&
+                hashed_subvol != local->cached_subvol) {
+                        /*
+                         * If hashed and cached are different, then we need
+                         * to unlink linkfile from hashed subvol if data
+                         * file is deleted successfully
+                         */
+                        STACK_WIND (frame, dht_unlink_linkfile_cbk,
+                                    hashed_subvol,
+                                    hashed_subvol->fops->unlink, &local->loc,
+                                    local->flags, xdata);
+                        return 0;
+                }
         }
 
-        STACK_WIND (frame, dht_unlink_cbk,
-                    cached_subvol, cached_subvol->fops->unlink,
-                    &local->loc, local->flags, NULL);
-
-        return 0;
+        DHT_STACK_UNWIND (unlink, frame, local->op_ret, local->op_errno,
+                          &local->preparent, &local->postparent, xdata);
 
-err:
-        DHT_STACK_UNWIND (unlink, frame, -1, local->op_errno,
-                          NULL, NULL, NULL);
         return 0;
 }
 
@@ -5625,7 +5636,6 @@ dht_unlink (call_frame_t *frame, xlator_t *this, loc_t *loc, int xflag,
             dict_t *xdata)
 {
         xlator_t    *cached_subvol = NULL;
-        xlator_t    *hashed_subvol = NULL;
         int          op_errno = -1;
         dht_local_t *local = NULL;
 
@@ -5640,15 +5650,6 @@ dht_unlink (call_frame_t *frame, xlator_t *this, loc_t *loc, int xflag,
                 goto err;
         }
 
-        hashed_subvol = dht_subvol_get_hashed (this, loc);
-        /* Dont fail unlink if hashed_subvol is NULL which can be the result
-         * of layout anomaly */
-        if (!hashed_subvol) {
-                gf_msg_debug (this->name, 0,
-                              "no subvolume in layout for path=%s",
-                              loc->path);
-        }
-
         cached_subvol = local->cached_subvol;
         if (!cached_subvol) {
                 gf_msg_debug (this->name, 0,
@@ -5658,15 +5659,9 @@ dht_unlink (call_frame_t *frame, xlator_t *this, loc_t *loc, int xflag,
         }
 
         local->flags = xflag;
-        if (hashed_subvol && hashed_subvol != cached_subvol) {
-                STACK_WIND (frame, dht_unlink_linkfile_cbk,
-                            hashed_subvol, hashed_subvol->fops->unlink, loc,
-                            xflag, xdata);
-        } else {
-                STACK_WIND (frame, dht_unlink_cbk,
-                            cached_subvol, cached_subvol->fops->unlink, loc,
-                            xflag, xdata);
-        }
+        STACK_WIND (frame, dht_unlink_cbk,
+                    cached_subvol, cached_subvol->fops->unlink, loc,
+                    xflag, xdata);
 
         return 0;
 err:
diff --git a/xlators/cluster/dht/src/dht-common.h b/xlators/cluster/dht/src/dht-common.h
index 5fa97a41881..31b8b6804b7 100644
--- a/xlators/cluster/dht/src/dht-common.h
+++ b/xlators/cluster/dht/src/dht-common.h
@@ -1149,6 +1149,9 @@ dht_layout_missing_dirs (dht_layout_t *layout);
 int
 dht_refresh_layout (call_frame_t *frame);
 
+gf_boolean_t
+dht_is_tier_xlator (xlator_t *this);
+
 int
 dht_build_parent_loc (xlator_t *this, loc_t *parent, loc_t *child,
                                                  int32_t *op_errno);
diff --git a/xlators/cluster/dht/src/tier-common.c b/xlators/cluster/dht/src/tier-common.c
index 129932c9ef9..0adf3387fe7 100644
--- a/xlators/cluster/dht/src/tier-common.c
+++ b/xlators/cluster/dht/src/tier-common.c
@@ -22,6 +22,302 @@
 #include "tier.h"
 
 int
+tier_unlink_nonhashed_linkfile_cbk (call_frame_t *frame, void *cookie,
+                                    xlator_t *this, int op_ret, int op_errno,
+                                    struct iatt *preparent,
+                                    struct iatt *postparent, dict_t *xdata)
+{
+        dht_local_t  *local = NULL;
+        call_frame_t *prev = NULL;
+
+        local = frame->local;
+        prev  = cookie;
+
+        LOCK (&frame->lock);
+        {
+                if ((op_ret == -1) && (op_errno != ENOENT)) {
+                        local->op_errno = op_errno;
+                        local->op_ret = op_ret;
+                        gf_msg_debug (this->name, op_errno,
+                                      "Unlink link: subvolume %s"
+                                      " returned -1",
+                                      prev->this->name);
+                        goto unlock;
+                }
+
+                local->op_ret = 0;
+        }
+unlock:
+        UNLOCK (&frame->lock);
+
+        if (local->op_ret == -1)
+                goto err;
+        DHT_STACK_UNWIND (unlink, frame, local->op_ret, local->op_errno,
+                          &local->preparent, &local->postparent, NULL);
+
+
+        return 0;
+
+err:
+        DHT_STACK_UNWIND (unlink, frame, -1, local->op_errno,
+                          NULL, NULL, NULL);
+        return 0;
+}
+
+int
+tier_unlink_lookup_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
+                        int op_ret, int op_errno, inode_t *inode,
+                        struct iatt *preparent, dict_t *xdata,
+                        struct iatt *postparent)
+{
+        dht_local_t             *local             = NULL;
+        call_frame_t            *prev              = NULL;
+        dht_conf_t              *conf              = NULL;
+        xlator_t                *hot_subvol        = NULL;
+
+        local = frame->local;
+        prev  = cookie;
+        conf = this->private;
+        hot_subvol = TIER_UNHASHED_SUBVOL;
+
+        if (!op_ret) {
+                /*
+                 * linkfile present on hot tier. unlinking the linkfile
+                 */
+                STACK_WIND (frame, tier_unlink_nonhashed_linkfile_cbk,
+                            hot_subvol, hot_subvol->fops->unlink,
+                            &local->loc, local->flags, NULL);
+                return 0;
+        }
+
+        LOCK (&frame->lock);
+        {
+                if (op_errno == ENOENT) {
+                        local->op_ret   = 0;
+                        local->op_errno = op_errno;
+                } else {
+                        local->op_ret = op_ret;
+                        local->op_errno = op_errno;
+                }
+                gf_msg_debug (this->name, op_errno,
+                              "Lookup : subvolume %s returned -1",
+                               prev->this->name);
+        }
+
+        UNLOCK (&frame->lock);
+
+        DHT_STACK_UNWIND (unlink, frame, local->op_ret, local->op_errno,
+                          &local->preparent, &local->postparent, xdata);
+
+        return 0;
+}
+
+int
+tier_unlink_linkfile_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
+                         int op_ret, int op_errno, struct iatt *preparent,
+                         struct iatt *postparent, dict_t *xdata)
+{
+        dht_local_t  *local = NULL;
+        call_frame_t *prev = NULL;
+
+        local = frame->local;
+        prev  = cookie;
+
+        LOCK (&frame->lock);
+        {
+                /* Ignore EINVAL for tier to ignore error when the file
+                        does not exist on the other tier  */
+                if ((op_ret == -1) && !((op_errno == ENOENT) ||
+                                        (op_errno == EINVAL))) {
+                        local->op_errno = op_errno;
+                        local->op_ret   = op_ret;
+                        gf_msg_debug (this->name, op_errno,
+                                      "Unlink link: subvolume %s"
+                                      " returned -1",
+                                      prev->this->name);
+                        goto unlock;
+                }
+
+                local->op_ret = 0;
+        }
+unlock:
+        UNLOCK (&frame->lock);
+
+        if (local->op_ret == -1)
+                goto err;
+
+        DHT_STACK_UNWIND (unlink, frame, local->op_ret, local->op_errno,
+                          &local->preparent, &local->postparent, xdata);
+
+        return 0;
+
+err:
+        DHT_STACK_UNWIND (unlink, frame, -1, local->op_errno,
+                          NULL, NULL, NULL);
+        return 0;
+}
+
+int32_t
+tier_unlink_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
+                int op_ret, int op_errno, struct iatt *preparent,
+                struct iatt *postparent, dict_t *xdata)
+{
+        dht_local_t     *local          = NULL;
+        call_frame_t    *prev           = NULL;
+        struct iatt     *stbuf          = NULL;
+        dht_conf_t      *conf           = NULL;
+        int              ret            = -1;
+        xlator_t        *hot_tier       = NULL;
+        xlator_t        *cold_tier      = NULL;
+
+        local = frame->local;
+        prev  = cookie;
+        conf  = this->private;
+
+        cold_tier = TIER_HASHED_SUBVOL;
+        hot_tier = TIER_UNHASHED_SUBVOL;
+
+        LOCK (&frame->lock);
+        {
+                if (op_ret == -1) {
+                        if (op_errno == ENOENT) {
+                                local->op_ret = 0;
+                        } else {
+                                local->op_ret   = -1;
+                                local->op_errno = op_errno;
+                        }
+                        gf_msg_debug (this->name, op_errno,
+                                      "Unlink: subvolume %s returned -1"
+                                      " with errno = %d",
+                                       prev->this->name, op_errno);
+                        goto unlock;
+                }
+
+                local->op_ret = 0;
+
+                local->postparent = *postparent;
+                local->preparent = *preparent;
+
+                if (local->loc.parent) {
+                        dht_inode_ctx_time_update (local->loc.parent, this,
+                                                   &local->preparent, 0);
+                        dht_inode_ctx_time_update (local->loc.parent, this,
+                                                   &local->postparent, 1);
+                }
+        }
+unlock:
+        UNLOCK (&frame->lock);
+
+        if (local->op_ret)
+                goto out;
+
+        if (cold_tier != local->cached_subvol) {
+                /*
+                 * File is present in hot tier, so there will be
+                 * a link file on cold tier, deleting the linkfile
+                 * from cold tier
+                 */
+                STACK_WIND (frame, tier_unlink_linkfile_cbk,
+                            cold_tier,
+                            cold_tier->fops->unlink, &local->loc,
+                            local->flags, xdata);
+                return 0;
+        }
+
+        ret = dict_get_bin (xdata, DHT_IATT_IN_XDATA_KEY, (void **) &stbuf);
+        if (!ret && stbuf && ((IS_DHT_MIGRATION_PHASE2 (stbuf)) ||
+                      IS_DHT_MIGRATION_PHASE1 (stbuf))) {
+                /*
+                 * File is migrating from cold to hot tier.
+                 * Delete the destination linkfile.
+                 */
+                STACK_WIND (frame, tier_unlink_lookup_cbk,
+                            hot_tier,
+                            hot_tier->fops->lookup,
+                            &local->loc, NULL);
+                return 0;
+
+        }
+
+out:
+        DHT_STACK_UNWIND (unlink, frame, local->op_ret, local->op_errno,
+                          &local->preparent, &local->postparent, xdata);
+
+        return 0;
+}
+
+int
+tier_unlink (call_frame_t *frame, xlator_t *this, loc_t *loc, int xflag,
+            dict_t *xdata)
+{
+        xlator_t                *cached_subvol = NULL;
+        xlator_t                *hashed_subvol = NULL;
+        dht_conf_t              *conf          = NULL;
+        int                      op_errno      = -1;
+        dht_local_t             *local         = NULL;
+        int                      ret           = -1;
+
+        VALIDATE_OR_GOTO (frame, err);
+        VALIDATE_OR_GOTO (this, err);
+        VALIDATE_OR_GOTO (loc, err);
+
+        conf = this->private;
+
+        local = dht_local_init (frame, loc, NULL, GF_FOP_UNLINK);
+        if (!local) {
+                op_errno = ENOMEM;
+
+                goto err;
+        }
+
+        hashed_subvol = TIER_HASHED_SUBVOL;
+
+        cached_subvol = local->cached_subvol;
+        if (!cached_subvol) {
+                gf_msg_debug (this->name, 0,
+                              "no cached subvolume for path=%s", loc->path);
+                op_errno = EINVAL;
+                goto err;
+        }
+
+        local->flags = xflag;
+        if (hashed_subvol == cached_subvol) {
+                /*
+                 * File resides in cold tier. We need to stat
+                 * the file to see if it is being promoted.
+                 * If yes we need to delete the destination
+                 * file as well.
+                 */
+                xdata = xdata ? dict_ref (xdata) : dict_new ();
+                if (xdata) {
+                        ret = dict_set_dynstr_with_alloc (xdata,
+                                DHT_IATT_IN_XDATA_KEY, "yes");
+                        if (ret) {
+                                gf_msg_debug (this->name, 0,
+                                        "Failed to set dictionary key %s",
+                                         DHT_IATT_IN_XDATA_KEY);
+                        }
+                }
+        }
+
+        /*
+         * File is on hot tier, delete the data file first, then
+         * linkfile from cold.
+         */
+        STACK_WIND (frame, tier_unlink_cbk,
+                    cached_subvol, cached_subvol->fops->unlink, loc,
+                    xflag, xdata);
+        if (xdata)
+                dict_unref (xdata);
+        return 0;
+err:
+        op_errno = (op_errno == -1) ? errno : op_errno;
+        DHT_STACK_UNWIND (unlink, frame, -1, op_errno, NULL, NULL, NULL);
+
+        return 0;
+}
+
+int
 tier_readdir_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
                  int op_ret, int op_errno, gf_dirent_t *orig_entries,
                  dict_t *xdata)
diff --git a/xlators/cluster/dht/src/tier-common.h b/xlators/cluster/dht/src/tier-common.h
index db5bc8c9226..a9d98eab36d 100644
--- a/xlators/cluster/dht/src/tier-common.h
+++ b/xlators/cluster/dht/src/tier-common.h
@@ -10,6 +10,11 @@
 
 #ifndef _TIER_COMMON_H_
 #define _TIER_COMMON_H_
+/* Function definitions */
+
+int32_t
+tier_unlink (call_frame_t *frame, xlator_t *this,
+             loc_t *loc, int xflag, dict_t *xdata);
 
 #ifndef _CONFIG_H
 #define _CONFIG_H
diff --git a/xlators/cluster/dht/src/tier.c b/xlators/cluster/dht/src/tier.c
index 92b5aa5f999..e883c1cba03 100644
--- a/xlators/cluster/dht/src/tier.c
+++ b/xlators/cluster/dht/src/tier.c
@@ -2348,7 +2348,7 @@ struct xlator_fops fops = {
         .readdirp    = tier_readdirp,
         .fsyncdir    = dht_fsyncdir,
         .symlink     = dht_symlink,
-        .unlink      = dht_unlink,
+        .unlink      = tier_unlink,
         .link        = dht_link,
         .mkdir       = dht_mkdir,
         .rmdir       = dht_rmdir,
diff --git a/xlators/storage/posix/src/posix.c b/xlators/storage/posix/src/posix.c
index bf3f8bd9b0b..473d73994e0 100644
--- a/xlators/storage/posix/src/posix.c
+++ b/xlators/storage/posix/src/posix.c
@@ -1607,6 +1607,66 @@ err:
         return -1;
 }
 
+static
+int32_t posix_set_iatt_in_dict (dict_t *dict, struct iatt *in_stbuf)
+{
+        int ret             = -1;
+        struct iatt *stbuf  = NULL;
+        int32_t len         = sizeof(struct iatt);
+
+        if (!dict || !in_stbuf)
+                return ret;
+
+        stbuf = GF_CALLOC (1, len, gf_common_mt_char);
+        if (!stbuf)
+                return ret;
+
+        memcpy (stbuf, in_stbuf, len);
+
+        ret = dict_set_bin (dict, DHT_IATT_IN_XDATA_KEY, stbuf, len);
+        if (ret)
+                GF_FREE (stbuf);
+
+        return ret;
+}
+
+gf_boolean_t
+posix_skip_non_linkto_unlink (dict_t *xdata, loc_t *loc, char *key,
+                              const char *linkto_xattr, struct iatt *stbuf,
+                              const char *real_path)
+{
+        gf_boolean_t     skip_unlink            = _gf_false;
+        gf_boolean_t     is_dht_linkto_file     = _gf_false;
+        int              unlink_if_linkto       = 0;
+        ssize_t          xattr_size             = -1;
+        int              op_ret                 = -1;
+
+        op_ret = dict_get_int32 (xdata, key,
+                                 &unlink_if_linkto);
+
+        if (!op_ret && unlink_if_linkto) {
+
+                is_dht_linkto_file =  IS_DHT_LINKFILE_MODE (stbuf);
+                if (!is_dht_linkto_file)
+                        return _gf_true;
+
+                LOCK (&loc->inode->lock);
+
+                xattr_size = sys_lgetxattr (real_path, linkto_xattr, NULL, 0);
+
+                if (xattr_size <= 0)
+                        skip_unlink = _gf_true;
+
+                UNLOCK (&loc->inode->lock);
+
+                gf_msg ("posix", GF_LOG_INFO, 0, P_MSG_XATTR_STATUS,
+                        "linkto_xattr status: %"PRIu32" for %s", skip_unlink,
+                        real_path);
+        }
+        return skip_unlink;
+
+}
+
 int32_t
 posix_unlink (call_frame_t *frame, xlator_t *this,
               loc_t *loc, int xflag, dict_t *xdata)
@@ -1617,6 +1677,7 @@ posix_unlink (call_frame_t *frame, xlator_t *this,
         char                   *par_path          = NULL;
         int32_t                fd                 = -1;
         struct iatt            stbuf              = {0,};
+        struct iatt            postbuf            = {0,};
         struct posix_private  *priv               = NULL;
         struct iatt            preparent          = {0,};
         struct iatt            postparent         = {0,};
@@ -1625,6 +1686,7 @@ posix_unlink (call_frame_t *frame, xlator_t *this,
         int32_t                unlink_if_linkto   = 0;
         int32_t                check_open_fd      = 0;
         int32_t                skip_unlink        = 0;
+        int32_t                fdstat_requested   = 0;
         int32_t                ctr_link_req       = 0;
         ssize_t                xattr_size         = -1;
         int32_t                is_dht_linkto_file = 0;
@@ -1678,40 +1740,30 @@ posix_unlink (call_frame_t *frame, xlator_t *this,
                         goto out;
                 }
         }
-
-
-        op_ret = dict_get_int32 (xdata, DHT_SKIP_NON_LINKTO_UNLINK,
-                                 &unlink_if_linkto);
-
-        if (!op_ret && unlink_if_linkto) {
-
-                LOCK (&loc->inode->lock);
-
-                xattr_size = sys_lgetxattr (real_path, LINKTO, NULL, 0);
-
-                if (xattr_size <= 0) {
-                        skip_unlink = 1;
-                } else {
-                       is_dht_linkto_file =  IS_DHT_LINKFILE_MODE (&stbuf);
-                       if (!is_dht_linkto_file)
-                               skip_unlink = 1;
-                }
-
-                UNLOCK (&loc->inode->lock);
-
-                gf_msg (this->name, GF_LOG_INFO, 0, P_MSG_XATTR_STATUS,
-                        "linkto_xattr status: %"PRIu32" for %s", skip_unlink,
-                        real_path);
-
-                if (skip_unlink) {
-                        op_ret = -1;
-                        op_errno = EBUSY;
-                        goto out;
-                }
+        /*
+         * If either of the function return true, skip_unlink.
+         * If first first function itself return true,
+         * we don't need to call second function, skip unlink.
+         */
+        skip_unlink = posix_skip_non_linkto_unlink (xdata, loc,
+                                                    DHT_SKIP_NON_LINKTO_UNLINK,
+                                                    DHT_LINKTO, &stbuf,
+                                                    real_path);
+        skip_unlink = skip_unlink || posix_skip_non_linkto_unlink (xdata, loc,
+                                                    TIER_SKIP_NON_LINKTO_UNLINK,
+                                                    TIER_LINKTO, &stbuf,
+                                                    real_path);
+        if (skip_unlink) {
+                op_ret = -1;
+                op_errno = EBUSY;
+                goto out;
         }
 
+        if (xdata && dict_get (xdata, DHT_IATT_IN_XDATA_KEY)) {
+                fdstat_requested = 1;
+        }
 
-        if (priv->background_unlink) {
+        if (priv->background_unlink || fdstat_requested) {
                 if (IA_ISREG (loc->inode->ia_type)) {
                         fd = open (real_path, O_RDONLY);
                         if (fd == -1) {
@@ -1754,6 +1806,24 @@ posix_unlink (call_frame_t *frame, xlator_t *this,
                 goto out;
         }
 
+        unwind_dict = dict_new ();
+        if (!unwind_dict) {
+                op_errno = -ENOMEM;
+                op_ret = -1;
+                goto out;
+        }
+        if (fdstat_requested) {
+                op_ret = posix_fdstat (this, fd, &postbuf);
+                if (op_ret == -1) {
+                        op_errno = errno;
+                        gf_msg (this->name, GF_LOG_ERROR, errno,
+                                P_MSG_FSTAT_FAILED, "post operation "
+                                "fstat failed on fd=%d", fd);
+                        goto out;
+                }
+                op_ret = posix_set_iatt_in_dict (unwind_dict, &postbuf);
+        }
+
         op_ret = posix_pstat (this, loc->pargfid, par_path, &postparent);
         if (op_ret == -1) {
                 op_errno = errno;
@@ -1763,7 +1833,7 @@ posix_unlink (call_frame_t *frame, xlator_t *this,
                 goto out;
         }
 
-        unwind_dict = posix_dict_set_nlink (xdata, NULL, stbuf.ia_nlink);
+        unwind_dict = posix_dict_set_nlink (xdata, unwind_dict, stbuf.ia_nlink);
         op_ret = 0;
 out:
         SET_TO_OLD_FS_ID ();
@@ -3362,31 +3432,6 @@ map_xattr_flags(int flags)
 }
 #endif
 
-static
-int32_t posix_set_iatt_in_dict (dict_t *dict, struct iatt *in_stbuf)
-{
-        int ret             = -1;
-        struct iatt *stbuf  = NULL;
-        int32_t len         = sizeof(struct iatt);
-
-        if (!dict || !in_stbuf)
-                return ret;
-
-        stbuf = GF_CALLOC (1, len, gf_common_mt_char);
-        if (!stbuf)
-                return ret;
-
-        memcpy (stbuf, in_stbuf, len);
-
-        ret = dict_set_bin (dict, DHT_IATT_IN_XDATA_KEY, stbuf, len);
-        if (ret)
-                GF_FREE (stbuf);
-
-        return ret;
-}
-
-
-
 int32_t
 posix_setxattr (call_frame_t *frame, xlator_t *this,
                 loc_t *loc, dict_t *dict, int flags, dict_t *xdata)
diff --git a/xlators/storage/posix/src/posix.h b/xlators/storage/posix/src/posix.h
index 9ed82fc4bbc..80ddab64b50 100644
--- a/xlators/storage/posix/src/posix.h
+++ b/xlators/storage/posix/src/posix.h
@@ -55,7 +55,11 @@
 
 #define ACL_BUFFER_MAX 4096 /* size of character buffer */
 
-#define LINKTO "trusted.glusterfs.dht.linkto"
+#define DHT_LINKTO "trusted.glusterfs.dht.linkto"
+/*
+ * TIER_MODE need to be changed when we stack tiers
+ */
+#define TIER_LINKTO "trusted.tier.tier-dht.linkto"
 
 #define POSIX_GFID_HANDLE_SIZE(base_path_len) (base_path_len + SLEN("/") \
                                                + SLEN(GF_HIDDEN_PATH) + SLEN("/") \