From 0f2adea7ae377ea2efbab388f3af7e2a048f5f68 Mon Sep 17 00:00:00 2001

From: karthik-us <ksubrahm@redhat.com>

Date: Wed, 17 Jan 2018 17:30:06 +0530

Subject: [PATCH 190/201] cluster/afr: Adding option to take full file lock

Problem:

In replica 3 volumes there is a possibilities of ending up in split

brain scenario, when multiple clients writing data on the same file

at non overlapping regions in parallel.

Scenario:

- Initially all the copies are good and all the clients gets the value

  of data readables as all good.

- Client C0 performs write W1 which fails on brick B0 and succeeds on

  other two bricks.

- C1 performs write W2 which fails on B1 and succeeds on other two bricks.

- C2 performs write W3 which fails on B2 and succeeds on other two bricks.

- All the 3 writes above happen in parallel and fall on different ranges

  so afr takes granular locks and all the writes are performed in parallel.

  Since each client had data-readables as good, it does not see

  file going into split-brain in the in_flight_split_brain check, hence

  performs the post-op marking the pending xattrs. Now all the bricks

  are being blamed by each other, ending up in split-brain.

Fix:

Have an option to take either full lock or range lock on files while

doing data transactions, to prevent the possibility of ending up in

split brains. With this change, by default the files will take full

lock while doing IO. If you want to make use of the old range lock

change the value of "cluster.full-lock" to "no".

Upstream patch: https://review.gluster.org/#/c/19218/

> Change-Id: I7893fa33005328ed63daa2f7c35eeed7c5218962

> BUG: 1535438

> Signed-off-by: karthik-us <ksubrahm@redhat.com>

Change-Id: I4d8b1c90bfff8f597cf7f7e49a71f5f6eb19f986

BUG: 1552414

Signed-off-by: karthik-us <ksubrahm@redhat.com>

Reviewed-on: https://code.engineering.redhat.com/gerrit/131966

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

Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>

---

 libglusterfs/src/globals.h                      | 4 +++-

 xlators/cluster/afr/src/afr-transaction.c       | 2 +-

 xlators/cluster/afr/src/afr.c                   | 8 ++++++++

 xlators/cluster/afr/src/afr.h                   | 5 +++--

 xlators/mgmt/glusterd/src/glusterd-volume-set.c | 7 +++++++

 5 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/libglusterfs/src/globals.h b/libglusterfs/src/globals.h

index 6bbe3e6..8fd3318 100644

--- a/libglusterfs/src/globals.h

+++ b/libglusterfs/src/globals.h

@@ -43,7 +43,7 @@

  */

 #define GD_OP_VERSION_MIN  1 /* MIN is the fresh start op-version, mostly

                                 should not change */

-#define GD_OP_VERSION_MAX  GD_OP_VERSION_3_13_1 /* MAX VERSION is the maximum

+#define GD_OP_VERSION_MAX  GD_OP_VERSION_3_13_2 /* MAX VERSION is the maximum

                                                   count in VME table, should

                                                   keep changing with

                                                   introduction of newer

@@ -107,6 +107,8 @@

 #define GD_OP_VERSION_3_13_1   31301 /* Op-version for GlusterFS 3.13.1 */

+#define GD_OP_VERSION_3_13_2   31302 /* Op-version for GlusterFS 3.13.2 */

+

 #include "xlator.h"

 /* THIS */

diff --git a/xlators/cluster/afr/src/afr-transaction.c b/xlators/cluster/afr/src/afr-transaction.c

index 97f9dd4..1c80c6b 100644

--- a/xlators/cluster/afr/src/afr-transaction.c

+++ b/xlators/cluster/afr/src/afr-transaction.c

@@ -1991,7 +1991,7 @@ afr_set_transaction_flock (xlator_t *this, afr_local_t *local)

         inodelk = afr_get_inodelk (int_lock, int_lock->domain);

         priv = this->private;

-        if (priv->arbiter_count &&

+        if ((priv->arbiter_count || priv->full_lock) &&

             local->transaction.type == AFR_DATA_TRANSACTION) {

                 /*Lock entire file to avoid network split brains.*/

                 inodelk->flock.l_len   = 0;

diff --git a/xlators/cluster/afr/src/afr.c b/xlators/cluster/afr/src/afr.c

index d3aee77..9493fbb 100644

--- a/xlators/cluster/afr/src/afr.c

+++ b/xlators/cluster/afr/src/afr.c

@@ -244,6 +244,7 @@ reconfigure (xlator_t *this, dict_t *options)

                           out);

         GF_OPTION_RECONF ("locking-scheme", priv->locking_scheme, options, str,

                           out);

+        GF_OPTION_RECONF ("full-lock", priv->full_lock, options, bool, out);

         GF_OPTION_RECONF ("use-compound-fops", priv->use_compound_fops,

                           options, bool,

                           out);

@@ -534,6 +535,7 @@ init (xlator_t *this)

         GF_OPTION_INIT ("pre-op-compat", priv->pre_op_compat, bool, out);

         GF_OPTION_INIT ("locking-scheme", priv->locking_scheme, str, out);

+        GF_OPTION_INIT ("full-lock", priv->full_lock, bool, out);

         GF_OPTION_INIT ("use-compound-fops", priv->use_compound_fops,

                         bool, out);

         GF_OPTION_INIT ("granular-entry-heal", priv->esh_granular, bool, out);

@@ -1084,6 +1086,12 @@ struct volume_options options[] = {

                          "stop being compatible with afr-v1, which helps afr "

                          "be more granular while self-healing",

         },

+        { .key = {"full-lock"},

+          .type = GF_OPTION_TYPE_BOOL,

+          .default_value = "yes",

+          .description = "If this option is disabled, then the IOs will take "

+                         "range locks same as versions till 3.13.1."

+        },

         { .key = {"granular-entry-heal"},

           .type = GF_OPTION_TYPE_BOOL,

           .default_value = "no",

diff --git a/xlators/cluster/afr/src/afr.h b/xlators/cluster/afr/src/afr.h

index c822221..b6f5388 100644

--- a/xlators/cluster/afr/src/afr.h

+++ b/xlators/cluster/afr/src/afr.h

@@ -178,9 +178,10 @@ typedef struct _afr_private {

 	void                   *pump_private;

 	gf_boolean_t           use_afr_in_pump;

 	char                   *locking_scheme;

-        gf_boolean_t            esh_granular;

+        gf_boolean_t           full_lock;

+        gf_boolean_t           esh_granular;

         gf_boolean_t           consistent_io;

-        gf_boolean_t            use_compound_fops;

+        gf_boolean_t           use_compound_fops;

 } afr_private_t;

diff --git a/xlators/mgmt/glusterd/src/glusterd-volume-set.c b/xlators/mgmt/glusterd/src/glusterd-volume-set.c

index b603c7f..8d3407d 100644

--- a/xlators/mgmt/glusterd/src/glusterd-volume-set.c

+++ b/xlators/mgmt/glusterd/src/glusterd-volume-set.c

@@ -1507,6 +1507,13 @@ struct volopt_map_entry glusterd_volopt_map[] = {

           .flags      = OPT_FLAG_CLIENT_OPT

         },

+        { .key        = "cluster.full-lock",

+          .voltype    = "cluster/replicate",

+          .type       = NO_DOC,

+          .op_version = GD_OP_VERSION_3_13_2,

+          .flags      = OPT_FLAG_CLIENT_OPT

+        },

+

         /* stripe xlator options */

         { .key         = "cluster.stripe-block-size",

           .voltype     = "cluster/stripe",

-- 

1.8.3.1