cluster/afr: Avoid setting split-brain outside inode locks

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.

Fix:
Self-heals are launched to inspect xattrs when the
data/metadata self-heal options are turned on.
Decision to set/reset split-brain flag is taken inside
appropriate locks.

Known Issue After fix:
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.
This bug is handled only in upstream.

Change-Id: I59a43d5ce7bf9ca35bff54a51bf4cfa55d717a9e
BUG: 833727
Signed-off-by: Pranith Kumar K <pranithk@gluster.com>
Reviewed-on: http://review.gluster.com/3691
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

5 files changed, 46 insertions, 34 deletions

diff --git a/xlators/cluster/afr/src/afr-common.c b/xlators/cluster/afr/src/afr-common.c
index 7973dfdde04..f416ed921ce 100644
--- a/xlators/cluster/afr/src/afr-common.c
+++ b/xlators/cluster/afr/src/afr-common.c
@@ -1220,7 +1220,7 @@ afr_detect_self_heal_by_lookup_status (afr_local_t *local, xlator_t *this,
         if ((local->success_count > 0) && split_brain &&
             IA_ISREG (local->cont.lookup.inode->ia_type)) {
                 local->self_heal.do_data_self_heal = _gf_true;
-                local->self_heal.do_gfid_self_heal    = _gf_true;
+                local->self_heal.do_metadata_self_heal = _gf_true;
                 gf_log (this->name, GF_LOG_WARNING,
                         "split brain detected during lookup of %s.",
                         local->loc.path);
@@ -1504,6 +1504,7 @@ afr_lookup_set_self_heal_params (afr_local_t *local, xlator_t *this)
         sh = &local->self_heal;
 
         split_brain = afr_is_split_brain (this, local->cont.lookup.inode);
+        split_brain = split_brain || local->cont.lookup.possible_spb;
         afr_detect_self_heal_by_lookup_status (local, this, split_brain);
 
         if (afr_lookup_gfid_missing_count (local, this))
diff --git a/xlators/cluster/afr/src/afr-self-heal-common.c b/xlators/cluster/afr/src/afr-self-heal-common.c
index 9e493092e2a..be8809a5de7 100644
--- a/xlators/cluster/afr/src/afr-self-heal-common.c
+++ b/xlators/cluster/afr/src/afr-self-heal-common.c
@@ -2144,7 +2144,7 @@ afr_self_heal_completion_cbk (call_frame_t *bgsh_frame, xlator_t *this)
         local = bgsh_frame->local;
         sh    = &local->self_heal;
 
-        if (local->govinda_gOvinda)
+        if (local->govinda_gOvinda || sh->mdata_spb || sh->data_spb)
                 split_brain = _gf_true;
 
         afr_set_split_brain (this, sh->inode, split_brain);
diff --git a/xlators/cluster/afr/src/afr-self-heal-data.c b/xlators/cluster/afr/src/afr-self-heal-data.c
index 90a2af18b5a..72bf8d4b917 100644
--- a/xlators/cluster/afr/src/afr-self-heal-data.c
+++ b/xlators/cluster/afr/src/afr-self-heal-data.c
@@ -740,16 +740,6 @@ 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)) {
@@ -772,12 +762,12 @@ 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,
@@ -790,6 +780,15 @@ afr_sh_data_fxattrop_fstat_done (call_frame_t *frame, xlator_t *this)
         if (sh->sync_done) {
                 afr_sh_data_setattr (frame, this);
         } else {
+                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;
+                }
+
                 afr_sh_data_fix (frame, this);
         }
         return 0;
@@ -831,9 +830,7 @@ 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;
@@ -1393,8 +1390,13 @@ 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);
-
+        /* Self-heal completion cbk changes inode split-brain status based on
+         * govinda_gOvinda, mdata_spb, data_spb values. 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 (sh->do_data_self_heal &&
             afr_data_self_heal_enabled (priv->data_self_heal)) {
                 afr_sh_data_open (frame, this);
diff --git a/xlators/cluster/afr/src/afr-self-heal-metadata.c b/xlators/cluster/afr/src/afr-self-heal-metadata.c
index 79718315cbf..6c3989e8490 100644
--- a/xlators/cluster/afr/src/afr-self-heal-metadata.c
+++ b/xlators/cluster/afr/src/afr-self-heal-metadata.c
@@ -50,7 +50,7 @@ afr_sh_metadata_done (call_frame_t *frame, xlator_t *this)
         sh = &local->self_heal;
 
         afr_sh_reset (frame, this);
-        if (local->govinda_gOvinda) {
+        if (sh->mdata_spb) {
                 gf_log (this->name, GF_LOG_INFO,
                         "split-brain detected, aborting selfheal of %s",
                         local->loc.path);
@@ -450,15 +450,6 @@ afr_sh_metadata_fix (call_frame_t *frame, xlator_t *this,
                                       sh->pending_matrix, sh->sources,
                                       sh->success_children,
                                       AFR_METADATA_TRANSACTION, NULL, _gf_false);
-        if (nsources == 0) {
-                gf_log (this->name, GF_LOG_TRACE,
-                        "No self-heal needed for %s",
-                        local->loc.path);
-
-                afr_sh_metadata_finish (frame, this);
-                goto out;
-        }
-
         if ((nsources == -1)
             && (priv->favorite_child != -1)
             && (sh->child_errno[priv->favorite_child] == 0)) {
@@ -480,7 +471,16 @@ afr_sh_metadata_fix (call_frame_t *frame, xlator_t *this,
                         "(possible split-brain). Please fix the file on "
                         "all backend volumes", local->loc.path);
 
-                local->govinda_gOvinda = 1;
+                sh->mdata_spb = _gf_true;
+
+                afr_sh_metadata_finish (frame, this);
+                goto out;
+        }
+        sh->mdata_spb = _gf_false;
+        if (nsources == 0) {
+                gf_log (this->name, GF_LOG_TRACE,
+                        "No self-heal needed for %s",
+                        local->loc.path);
 
                 afr_sh_metadata_finish (frame, this);
                 goto out;
@@ -584,10 +584,19 @@ int
 afr_self_heal_metadata (call_frame_t *frame, xlator_t *this)
 {
         afr_local_t   *local = NULL;
+        afr_self_heal_t *sh = NULL;
         afr_private_t *priv = this->private;
 
-
         local = frame->local;
+        sh = &local->self_heal;
+
+        /* Self-heal completion cbk changes inode split-brain status based on
+         * govinda_gOvinda, mdata_spb, data_spb values. Initialize mdata_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->mdata_spb = afr_is_split_brain (this, sh->inode);
 
         if (local->self_heal.do_metadata_self_heal && priv->metadata_self_heal) {
                 afr_sh_metadata_lock (frame, this);
diff --git a/xlators/cluster/afr/src/afr.h b/xlators/cluster/afr/src/afr.h
index 795db603528..fe0e2b2e6ed 100644
--- a/xlators/cluster/afr/src/afr.h
+++ b/xlators/cluster/afr/src/afr.h
@@ -261,6 +261,8 @@ typedef struct {
         int (*algo_completion_cbk) (call_frame_t *frame, xlator_t *this);
         int (*algo_abort_cbk) (call_frame_t *frame, xlator_t *this);
         void (*gfid_sh_success_cbk) (call_frame_t *sh_frame, xlator_t *this);
+        gf_boolean_t mdata_spb;
+        gf_boolean_t data_spb;
 
         call_frame_t *sh_frame;
 } afr_self_heal_t;
@@ -368,10 +370,7 @@ typedef struct _afr_local {
         unsigned int call_count;
         unsigned int success_count;
         unsigned int enoent_count;
-
-
         unsigned int govinda_gOvinda;
-
         unsigned int read_child_index;
         unsigned char read_child_returned;
         unsigned int first_up_child;
@@ -439,6 +438,7 @@ typedef struct _afr_local {
                         int32_t *sources;
                         int32_t *success_children;
                         gf_boolean_t fresh_lookup;
+                        gf_boolean_t possible_spb;
                 } lookup;
 
                 struct {