cluster/afr: Don't start heal when lookup succeeds on < 2 children

        Backport of http://review.gluster.org/8698

Problem:
When self-heal code doesn't see at least 2 successes on looking up children,
then self-heal can't be done. What is happening now is if all the lookups fail
then the pending changelog is all zeros in xattrs so all the children are
becoming sources and leading to crashes when the code paths further assume that
some data structures are populated properly

Fix:
Don't proceed with self-heals when < 2 children succeed lookups.

BUG: 1145726
Change-Id: I65465843f0e554c8ccdd8fa930ab42ac123ec023
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/8824
Reviewed-by: Krutika Dhananjay <kdhananj@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

6 files changed, 29 insertions, 8 deletions

diff --git a/xlators/cluster/afr/src/afr-self-heal-common.c b/xlators/cluster/afr/src/afr-self-heal-common.c
index 0158948d72..b104e6b786 100644
--- a/xlators/cluster/afr/src/afr-self-heal-common.c
+++ b/xlators/cluster/afr/src/afr-self-heal-common.c
@@ -324,6 +324,12 @@ afr_selfheal_find_direction (xlator_t *this, struct afr_reply *replies,
 	accused = alloca0 (priv->child_count);
 	matrix = ALLOC_MATRIX(priv->child_count, int);
 
+        if (afr_success_count (replies,
+                               priv->child_count) < AFR_SH_MIN_PARTICIPANTS) {
+                /* Treat this just like locks not being acquired */
+                return -ENOTCONN;
+        }
+
 	/* First construct the pending matrix for further analysis */
 	afr_selfheal_extract_xattr (this, replies, type, dirty, matrix);
 
@@ -502,6 +508,17 @@ afr_selfheal_unlocked_discover (call_frame_t *frame, inode_t *inode,
 						  priv->child_up);
 }
 
+unsigned int
+afr_success_count (struct afr_reply *replies, unsigned int count)
+{
+        int     i = 0;
+        unsigned int success = 0;
+
+        for (i = 0; i < count; i++)
+                if (replies[i].valid && replies[i].op_ret == 0)
+                        success++;
+        return success;
+}
 
 int
 afr_selfheal_lock_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
diff --git a/xlators/cluster/afr/src/afr-self-heal-data.c b/xlators/cluster/afr/src/afr-self-heal-data.c
index 455648b756..bee7682a23 100644
--- a/xlators/cluster/afr/src/afr-self-heal-data.c
+++ b/xlators/cluster/afr/src/afr-self-heal-data.c
@@ -508,7 +508,7 @@ __afr_selfheal_data (call_frame_t *frame, xlator_t *this, fd_t *fd,
 	ret = afr_selfheal_inodelk (frame, this, fd->inode, this->name, 0, 0,
 				    data_lock);
 	{
-		if (ret < 2) {
+		if (ret < AFR_SH_MIN_PARTICIPANTS) {
 			ret = -ENOTCONN;
 			goto unlock;
 		}
@@ -611,7 +611,7 @@ afr_selfheal_data (call_frame_t *frame, xlator_t *this, inode_t *inode)
 	ret = afr_selfheal_tryinodelk (frame, this, inode, priv->sh_domain, 0, 0,
 				       locked_on);
 	{
-		if (ret < 2) {
+		if (ret < AFR_SH_MIN_PARTICIPANTS) {
 			/* Either less than two subvols available, or another
 			   selfheal (from another server) is in progress. Skip
 			   for now in any case there isn't anything to do.
diff --git a/xlators/cluster/afr/src/afr-self-heal-entry.c b/xlators/cluster/afr/src/afr-self-heal-entry.c
index 0cf65009c5..45ce881e12 100644
--- a/xlators/cluster/afr/src/afr-self-heal-entry.c
+++ b/xlators/cluster/afr/src/afr-self-heal-entry.c
@@ -283,7 +283,7 @@ afr_selfheal_entry_dirent (call_frame_t *frame, xlator_t *this, fd_t *fd,
 	ret = afr_selfheal_entrylk (frame, this, fd->inode, this->name,
 				    name, locked_on);
 	{
-		if (ret < 2) {
+		if (ret < AFR_SH_MIN_PARTICIPANTS) {
 			ret = -ENOTCONN;
 			goto unlock;
 		}
@@ -491,7 +491,7 @@ __afr_selfheal_entry (call_frame_t *frame, xlator_t *this, fd_t *fd,
 	ret = afr_selfheal_entrylk (frame, this, fd->inode, this->name, NULL,
 				    data_lock);
 	{
-		if (ret < 2) {
+		if (ret < AFR_SH_MIN_PARTICIPANTS) {
 			ret = -ENOTCONN;
 			goto unlock;
 		}
@@ -567,7 +567,7 @@ afr_selfheal_entry (call_frame_t *frame, xlator_t *this, inode_t *inode)
 	ret = afr_selfheal_tryentrylk (frame, this, inode, priv->sh_domain, NULL,
 				       locked_on);
 	{
-		if (ret < 2) {
+		if (ret < AFR_SH_MIN_PARTICIPANTS) {
 			/* Either less than two subvols available, or another
 			   selfheal (from another server) is in progress. Skip
 			   for now in any case there isn't anything to do.
diff --git a/xlators/cluster/afr/src/afr-self-heal-metadata.c b/xlators/cluster/afr/src/afr-self-heal-metadata.c
index e98728ba54..2c5f3fd652 100644
--- a/xlators/cluster/afr/src/afr-self-heal-metadata.c
+++ b/xlators/cluster/afr/src/afr-self-heal-metadata.c
@@ -228,7 +228,7 @@ __afr_selfheal_metadata (call_frame_t *frame, xlator_t *this, inode_t *inode,
 	ret = afr_selfheal_inodelk (frame, this, inode, this->name,
 				    LLONG_MAX - 1, 0, data_lock);
 	{
-		if (ret < 2) {
+		if (ret < AFR_SH_MIN_PARTICIPANTS) {
 			ret = -ENOTCONN;
 			goto unlock;
 		}
@@ -274,7 +274,7 @@ afr_selfheal_metadata (call_frame_t *frame, xlator_t *this, inode_t *inode)
 	ret = afr_selfheal_tryinodelk (frame, this, inode, priv->sh_domain, 0, 0,
 				       locked_on);
 	{
-		if (ret < 2) {
+		if (ret < AFR_SH_MIN_PARTICIPANTS) {
 			/* Either less than two subvols available, or another
 			   selfheal (from another server) is in progress. Skip
 			   for now in any case there isn't anything to do.
diff --git a/xlators/cluster/afr/src/afr-self-heal-name.c b/xlators/cluster/afr/src/afr-self-heal-name.c
index a3020f4e1a..c5d126185c 100644
--- a/xlators/cluster/afr/src/afr-self-heal-name.c
+++ b/xlators/cluster/afr/src/afr-self-heal-name.c
@@ -571,7 +571,7 @@ afr_selfheal_name_do (call_frame_t *frame, xlator_t *this, inode_t *parent,
 	ret = afr_selfheal_entrylk (frame, this, parent, this->name, bname,
 				    locked_on);
 	{
-		if (ret < 2) {
+		if (ret < AFR_SH_MIN_PARTICIPANTS) {
 			ret = -ENOTCONN;
 			goto unlock;
 		}
diff --git a/xlators/cluster/afr/src/afr-self-heal.h b/xlators/cluster/afr/src/afr-self-heal.h
index 31f12a4e74..7936659e5e 100644
--- a/xlators/cluster/afr/src/afr-self-heal.h
+++ b/xlators/cluster/afr/src/afr-self-heal.h
@@ -12,6 +12,7 @@
 #ifndef _AFR_SELFHEAL_H
 #define _AFR_SELFHEAL_H
 
+#define AFR_SH_MIN_PARTICIPANTS 2
 
 /* Perform fop on all UP subvolumes and wait for all callbacks to return */
 
@@ -181,4 +182,7 @@ afr_selfheal_newentry_mark (call_frame_t *frame, xlator_t *this, inode_t *inode,
 
 inode_t*
 afr_inode_link (inode_t *inode, struct iatt *iatt);
+
+unsigned int
+afr_success_count (struct afr_reply *replies, unsigned int count);
 #endif /* !_AFR_SELFHEAL_H */