From c1e17987f2399999707f464b13fcbd316b17af59 Mon Sep 17 00:00:00 2001

From: Krutika Dhananjay <kdhananj@redhat.com>

Date: Thu, 15 Feb 2018 16:12:12 +0530

Subject: [PATCH 170/180] features/shard: Fix shard inode refcount when it's

 part of priv->lru_list.

For as long as a shard's inode is in priv->lru_list, it should have a non-zero

ref-count. This patch achieves it by taking a ref on the inode when it

is added to lru list. When it's time for the inode to be evicted

from the lru list, a corresponding unref is done.

> Upstream: https://review.gluster.org/19608

> BUG: 1468483

> Change-Id: I289ffb41e7be5df7489c989bc1bbf53377433c86

Change-Id: Id540d44643b24a1be2198c48e35e478081368676

BUG: 1493085

Signed-off-by: Krutika Dhananjay <kdhananj@redhat.com>

Reviewed-on: https://code.engineering.redhat.com/gerrit/131736

Tested-by: RHGS Build Bot <nigelb@redhat.com>

Reviewed-by: Atin Mukherjee <amukherj@redhat.com>

---

 tests/bugs/shard/shard-inode-refcount-test.t | 27 +++++++++++++++++++++++++++

 tests/volume.rc                              | 18 ++++++++++++++++++

 xlators/features/shard/src/shard.c           | 26 +++++++++++++++++---------

 3 files changed, 62 insertions(+), 9 deletions(-)

 create mode 100644 tests/bugs/shard/shard-inode-refcount-test.t

diff --git a/tests/bugs/shard/shard-inode-refcount-test.t b/tests/bugs/shard/shard-inode-refcount-test.t

new file mode 100644

index 0000000..6358097

--- /dev/null

+++ b/tests/bugs/shard/shard-inode-refcount-test.t

@@ -0,0 +1,27 @@

+#!/bin/bash

+

+. $(dirname $0)/../../include.rc

+. $(dirname $0)/../../volume.rc

+

+cleanup

+

+TEST glusterd

+TEST pidof glusterd

+TEST $CLI volume create $V0 $H0:$B0/${V0}0

+TEST $CLI volume set $V0 features.shard on

+TEST $CLI volume set $V0 features.shard-block-size 4MB

+TEST $CLI volume start $V0

+

+TEST glusterfs --volfile-id=$V0 --volfile-server=$H0 $M0

+

+TEST dd if=/dev/zero of=$M0/one-plus-five-shards bs=1M count=23

+

+ACTIVE_INODES_BEFORE=$(get_mount_active_size_value $V0)

+TEST rm -f $M0/one-plus-five-shards

+EXPECT `expr $ACTIVE_INODES_BEFORE - 5` get_mount_active_size_value $V0

+

+EXPECT_WITHIN $UMOUNT_TIMEOUT "Y" force_umount $M0

+TEST $CLI volume stop $V0

+TEST $CLI volume delete $V0

+

+cleanup

diff --git a/tests/volume.rc b/tests/volume.rc

index 1ca17ab..a15c8e5 100644

--- a/tests/volume.rc

+++ b/tests/volume.rc

@@ -808,3 +808,21 @@ function get_fd_count {

         rm -f $statedump

         echo $count

 }

+

+function get_mount_active_size_value {

+        local vol=$1

+        local statedump=$(generate_mount_statedump $vol)

+        sleep 1

+        local val=$(grep "active_size" $statedump | cut -f2 -d'=' | tail -1)

+        rm -f $statedump

+        echo $val

+}

+

+function get_mount_lru_size_value {

+        local vol=$1

+        local statedump=$(generate_mount_statedump $vol)

+        sleep 1

+        local val=$(grep "lru_size" $statedump | cut -f2 -d'=' | tail -1)

+        rm -f $statedump

+        echo $val

+}

diff --git a/xlators/features/shard/src/shard.c b/xlators/features/shard/src/shard.c

index 7677a14..49cf04a 100644

--- a/xlators/features/shard/src/shard.c

+++ b/xlators/features/shard/src/shard.c

@@ -502,6 +502,10 @@ __shard_update_shards_inode_list (inode_t *linked_inode, xlator_t *this,

                  * by empty list), and if there is still space in the priv list,

                  * add this ctx to the tail of the list.

                  */

+                        /* For as long as an inode is in lru list, we try to

+                         * keep it alive by holding a ref on it.

+                         */

+                        inode_ref (linked_inode);

                         gf_uuid_copy (ctx->base_gfid, base_inode->gfid);

                         ctx->block_num = block_num;

                         list_add_tail (&ctx->ilist, &priv->ilist_head);

@@ -527,8 +531,16 @@ __shard_update_shards_inode_list (inode_t *linked_inode, xlator_t *this,

                         /* The following unref corresponds to the ref held by

                          * inode_find() above.

                          */

-                        inode_forget (lru_inode, 0);

                         inode_unref (lru_inode);

+                        /* The following unref corresponds to the ref held at

+                         * the time the shard was created or looked up

+                         */

+                        inode_unref (lru_inode);

+                        inode_forget (lru_inode, 0);

+                        /* For as long as an inode is in lru list, we try to

+                         * keep it alive by holding a ref on it.

+                         */

+                        inode_ref (linked_inode);

                         gf_uuid_copy (ctx->base_gfid, base_inode->gfid);

                         ctx->block_num = block_num;

                         list_add_tail (&ctx->ilist, &priv->ilist_head);

@@ -1658,11 +1670,6 @@ shard_link_block_inode (shard_local_t *local, int block_num, inode_t *inode,

                                    buf);

         inode_lookup (linked_inode);

         list_index = block_num - local->first_block;

-

-        /* Defer unref'ing the inodes until write is complete. These inodes are

-         * unref'd in the event of a failure or after successful fop completion

-         * in shard_local_wipe().

-         */

         local->inode_list[list_index] = linked_inode;

         LOCK(&priv->lock);

@@ -2520,10 +2527,11 @@ shard_unlink_block_inode (shard_local_t *local, int shard_block_num)

                 if (!list_empty (&ctx->ilist)) {

                         list_del_init (&ctx->ilist);

                         priv->inode_count--;

+                        GF_ASSERT (priv->inode_count >= 0);

+                        inode_unlink (inode, priv->dot_shard_inode, block_bname);

+                        inode_unref (inode);

+                        inode_forget (inode, 0);

                 }

-                GF_ASSERT (priv->inode_count >= 0);

-                inode_unlink (inode, priv->dot_shard_inode, block_bname);

-                inode_forget (inode, 0);

         }

         UNLOCK(&priv->lock);

-- 

1.8.3.1