From 3ca2971df5aeb8f67a39f5fa2866e68a54fdd9ce Mon Sep 17 00:00:00 2001

From: Dan Lambright <dlambrig@redhat.com>

Date: Thu, 11 Jun 2015 10:50:41 -0400

Subject: [PATCH 54/57] cluster/tier: account for reordered layouts

This is a backport of fix 11092.

> For a tiered volume the cold subvolume is always at a fixed

> position in the graph. DHT's layout array, on the other hand,

> may have the cold subvolume in either the first or second

> index, therefore code cannot make any assumptions. The fix

> searches the layout for the correct position dynamically

> rather than statically.

> The bug manifested itself in NFS, in which a newly attached

> subvolume had not received an existing directory. This case

> is a "stale entry" and marked as such in the layout for

> that directory.  The code did not see this, because it

> looked at the wrong index in the layout array.

> The fix also adds the check for decomissioned bricks, and

> fixes a problem in detach tier related to starting the

> rebalance process: we never received the right defrag

> command and it did not get directed to the tier translator.

> Change-Id: I77cdf9fbb0a777640c98003188565a79be9d0b56

> BUG: 1214289

> Signed-off-by: Dan Lambright <dlambrig@redhat.com>

> Signed-off-by: Dan Lambright <dlambrig@redhat.com>

Change-Id: I402105623c8fe0af416c4b7e22ed77f1b95d9847

BUG: 1228643

Signed-off-by: Dan Lambright <dlambrig@redhat.com>

Reviewed-on: https://code.engineering.redhat.com/gerrit/50560

Tested-by: Joseph Fernandes <josferna@redhat.com>

Reviewed-by: Joseph Fernandes <josferna@redhat.com>

Reviewed-by: Shyam Ranganathan <srangana@redhat.com>

---

 xlators/cluster/dht/src/dht-common.c           |    3 +-

 xlators/cluster/dht/src/tier.c                 |   43 ++++++++++++++++-------

 xlators/mgmt/glusterd/src/glusterd-brick-ops.c |    6 +++-

 3 files changed, 37 insertions(+), 15 deletions(-)

diff --git a/xlators/cluster/dht/src/dht-common.c b/xlators/cluster/dht/src/dht-common.c

index 6d70f82..8870a30 100644

--- a/xlators/cluster/dht/src/dht-common.c

+++ b/xlators/cluster/dht/src/dht-common.c

@@ -7089,7 +7089,8 @@ int32_t dht_migration_needed(xlator_t *this)

         defrag = conf->defrag;

-        if (defrag->cmd != GF_DEFRAG_CMD_START_TIER)

+        if ((defrag->cmd != GF_DEFRAG_CMD_START_TIER) &&

+            (defrag->cmd != GF_DEFRAG_CMD_START_DETACH_TIER))

                 ret = 1;

 out:

diff --git a/xlators/cluster/dht/src/tier.c b/xlators/cluster/dht/src/tier.c

index 0a9c073..cef4f5c 100644

--- a/xlators/cluster/dht/src/tier.c

+++ b/xlators/cluster/dht/src/tier.c

@@ -916,7 +916,8 @@ tier_migration_needed (xlator_t *this)

         defrag = conf->defrag;

-        if (defrag->cmd == GF_DEFRAG_CMD_START_TIER)

+        if ((defrag->cmd == GF_DEFRAG_CMD_START_TIER) ||

+            (defrag->cmd == GF_DEFRAG_CMD_START_DETACH_TIER))

                 ret = 1;

 out:

         return ret;

@@ -958,9 +959,11 @@ tier_search (xlator_t *this, dht_layout_t *layout, const char *name)

 {

         xlator_t                *subvol = NULL;

         void                    *value;

-        int                      search_first_subvol = 0;

+        int                      search_subvol = 0;

         dht_conf_t              *conf   = NULL;

         gf_defrag_info_t        *defrag = NULL;

+        int                      layout_cold = 0;

+        int                      layout_hot = 1;

         GF_VALIDATE_OR_GOTO("tier", this, out);

         GF_VALIDATE_OR_GOTO(this->name, layout, out);

@@ -969,28 +972,42 @@ tier_search (xlator_t *this, dht_layout_t *layout, const char *name)

         conf = this->private;

+        /* The first subvolume in the graph is always cold. */

+        /* Find the position of the cold subvolume in the layout. */

+        layout_cold = 0;

+        layout_hot = 1;

+        if (conf->subvolumes[0] != layout->list[0].xlator) {

+                layout_cold = 1;

+                layout_hot = 0;

+        }

+

+        search_subvol = layout_hot;

+

         defrag = conf->defrag;

         if (defrag && defrag->cmd == GF_DEFRAG_CMD_START_DETACH_TIER)

-                search_first_subvol = 1;

+                search_subvol = layout_cold;

+        /* "decommission_subvols_cnt" can only be non-zero on detach. */

+        /* This will change once brick add/remove is supported for */

+        /* tiered volumes. */

+        else if (conf->decommission_subvols_cnt) {

+                search_subvol = layout_cold;

+        }

         else if (!dict_get_ptr (this->options, "rule", &value) &&

-                 !strcmp(layout->list[0].xlator->name, value)) {

-                search_first_subvol = 1;

+                 !strcmp(layout->list[layout_cold].xlator->name, value)) {

+                search_subvol = layout_cold;

         }

-        if ((layout->list[0].err > 0) && (layout->list[0].err != ENOTCONN))

-                search_first_subvol = 0;

+        if ((layout->list[search_subvol].err > 0) &&

+            (layout->list[search_subvol].err != ENOTCONN))

+                search_subvol = layout_cold;

-        if (search_first_subvol)

-                subvol = layout->list[0].xlator;

-        else

-                subvol = layout->list[1].xlator;

+        subvol = layout->list[search_subvol].xlator;

+ out:

-out:

         return subvol;

 }

-

 dht_methods_t tier_methods = {

         .migration_get_dst_subvol = tier_migration_get_dst,

         .migration_other = tier_start,

diff --git a/xlators/mgmt/glusterd/src/glusterd-brick-ops.c b/xlators/mgmt/glusterd/src/glusterd-brick-ops.c

index 0af86f5..aa3a6c9 100644

--- a/xlators/mgmt/glusterd/src/glusterd-brick-ops.c

+++ b/xlators/mgmt/glusterd/src/glusterd-brick-ops.c

@@ -2039,6 +2039,7 @@ glusterd_op_remove_brick (dict_t *dict, char **op_errstr)

         char                    *brick_tmpstr  = NULL;

         int                      start_remove  = 0;

         uint32_t                 commit_hash   = 0;

+        int                      defrag_cmd    = 0;

         this = THIS;

         GF_ASSERT (this);

@@ -2309,9 +2310,12 @@ glusterd_op_remove_brick (dict_t *dict, char **op_errstr)

                         volinfo->rebal.commit_hash = commit_hash;

                 }

                 /* perform the rebalance operations */

+                defrag_cmd = GF_DEFRAG_CMD_START_FORCE;

+                if (cmd == GF_OP_CMD_DETACH_START)

+                        defrag_cmd = GF_DEFRAG_CMD_START_DETACH_TIER;

                 ret = glusterd_handle_defrag_start

                         (volinfo, err_str, sizeof (err_str),

-                         GF_DEFRAG_CMD_START_FORCE,

+                         defrag_cmd,

                          glusterd_remove_brick_migrate_cbk, GD_OP_REMOVE_BRICK);

                 if (!ret)

-- 

1.7.1