cluster/afr: Modified split-brain handling

RCA
The bug is observed because the decision to mark
a file in split-brain is taken outside appropriate locks.
Lookup gathers xattrs outside any lock. The xattrs being
in split-brain in lookup should only be taken as a hint.
Appropriate inodelks should be taken before confirming
a split-brain. Self-heal confirms this at the moment.
If data/metadata self-heal is turned off, inspecting of
xattrs could not be performed so split-brain behavior
does not work correctly if the self-heal options are turned off.

Fix
Self-heals are launched to inspect xattrs even when the
data/metadata self-heal options are turned off. The decision
to heal data/metadata after the xattrs are inspected is based
on whether the options are turned on/off. So decision to set/reset
split-brain flag is taken inside appropriate locks.

Testcases:
tests 33-36 in
https://github.com/pranithk/gluster-tests/blob/master/afr/self-heal.sh

Change-Id: Ia8aeab08208b50c06609ad35a9d72f3d553ee343
BUG: 833727
Signed-off-by: Pranith Kumar K <pranithk@gluster.com>
Reviewed-on: http://review.gluster.com/3626
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>

1 files changed, 37 insertions, 26 deletions

diff --git a/xlators/cluster/afr/src/afr-self-heal-data.c b/xlators/cluster/afr/src/afr-self-heal-data.c
index 1672b4f282e..6619c1353c7 100644
--- a/xlators/cluster/afr/src/afr-self-heal-data.c
+++ b/xlators/cluster/afr/src/afr-self-heal-data.c
@@ -688,16 +688,6 @@ afr_sh_data_fxattrop_fstat_done (call_frame_t *frame, xlator_t *this)
         nsources = afr_build_sources (this, sh->xattr, sh->buf, sh->pending_matrix,
                                       sh->sources, sh->success_children,
                                       AFR_DATA_TRANSACTION, NULL, _gf_true);
-        if ((nsources == 0) && !sh->sync_done) {
-                gf_log (this->name, GF_LOG_DEBUG,
-                        "No self-heal needed for %s",
-                        local->loc.path);
-
-                local->govinda_gOvinda = 0;
-                afr_sh_data_finish (frame, this);
-                return 0;
-        }
-
         if ((nsources == -1)
             && (priv->favorite_child != -1)
             && (sh->child_errno[priv->favorite_child] == 0)) {
@@ -720,12 +710,12 @@ afr_sh_data_fxattrop_fstat_done (call_frame_t *frame, xlator_t *this)
                         "split-brain). Please delete the file from all but "
                         "the preferred subvolume.", local->loc.path);
 
-                local->govinda_gOvinda = 1;
+                sh->data_spb = _gf_true;
                 afr_sh_data_fail (frame, this);
                 return 0;
         }
 
-        local->govinda_gOvinda = 0;
+        sh->data_spb = _gf_false;
         ret = afr_sh_inode_set_read_ctx (sh, this);
         if (ret) {
                 gf_log (this->name, GF_LOG_DEBUG,
@@ -738,7 +728,20 @@ afr_sh_data_fxattrop_fstat_done (call_frame_t *frame, xlator_t *this)
         if (sh->sync_done) {
                 afr_sh_data_setattr (frame, this);
         } else {
-                afr_sh_data_fix (frame, this);
+                if (nsources == 0) {
+                        gf_log (this->name, GF_LOG_DEBUG,
+                                "No self-heal needed for %s",
+                                local->loc.path);
+
+                        afr_sh_data_finish (frame, this);
+                        return 0;
+                }
+
+                if (sh->do_data_self_heal &&
+                    afr_data_self_heal_enabled (priv->data_self_heal))
+                        afr_sh_data_fix (frame, this);
+                else
+                        afr_sh_data_finish (frame, this);
         }
         return 0;
 }
@@ -764,11 +767,7 @@ afr_lookup_select_read_child_by_txn_type (xlator_t *this, afr_local_t *local,
         bufs = local->cont.lookup.bufs;
         success_children = local->cont.lookup.success_children;
 
-        pending_matrix = afr_matrix_create (priv->child_count,
-                                            priv->child_count);
-        if (NULL == pending_matrix)
-                goto out;
-
+        pending_matrix = local->cont.lookup.pending_matrix;
         sources = local->cont.lookup.sources;
         memset (sources, 0, sizeof (*sources) * priv->child_count);
 
@@ -780,9 +779,7 @@ afr_lookup_select_read_child_by_txn_type (xlator_t *this, afr_local_t *local,
                         local->loc.path);
                 switch (txn_type) {
                 case AFR_DATA_TRANSACTION:
-                        afr_set_split_brain (this,
-                                             local->cont.lookup.inode,
-                                             _gf_true);
+                        local->cont.lookup.possible_spb = _gf_true;
                         nsources = 1;
                         sources[success_children[0]] = 1;
                         break;
@@ -809,7 +806,6 @@ afr_lookup_select_read_child_by_txn_type (xlator_t *this, afr_local_t *local,
                                                         sources,
                                                         priv->hash_mode, gfid);
 out:
-        afr_matrix_cleanup (pending_matrix, priv->child_count);
         gf_log (this->name, GF_LOG_DEBUG, "returning read_child: %d",
                 read_child);
         return read_child;
@@ -1351,6 +1347,17 @@ afr_sh_non_reg_lock_success (call_frame_t *frame, xlator_t *this)
         return 0;
 }
 
+gf_boolean_t
+afr_can_start_data_self_heal (afr_self_heal_t *sh, afr_private_t *priv)
+{
+        if (sh->force_confirm_spb)
+                return _gf_true;
+        if (sh->do_data_self_heal &&
+            afr_data_self_heal_enabled (priv->data_self_heal))
+                return _gf_true;
+        return _gf_false;
+}
+
 int
 afr_self_heal_data (call_frame_t *frame, xlator_t *this)
 {
@@ -1361,10 +1368,14 @@ afr_self_heal_data (call_frame_t *frame, xlator_t *this)
         local = frame->local;
         sh = &local->self_heal;
 
-        local->govinda_gOvinda = afr_is_split_brain (this, sh->inode);
-
-        if (sh->do_data_self_heal &&
-            afr_data_self_heal_enabled (priv->data_self_heal)) {
+        /* Self-heal completion cbk changes inode split-brain status based on
+         * govinda_gOvinda, mdata_spb, data_spb value.
+         * Initialize data_spb with current split-brain status.
+         * If for some reason self-heal fails(locking phase etc), it makes sure
+         * we retain the split-brain status before this self-heal started.
+         */
+        sh->data_spb = afr_is_split_brain (this, sh->inode);
+        if (afr_can_start_data_self_heal (sh, priv)) {
                 if (IA_ISREG (sh->type)) {
                         afr_sh_data_open (frame, this);
                 } else {