afr: don't update readables if inode refresh failed on all children

Backport of: https://review.gluster.org/#/c/20029/
3.12 still supports quorum-reads, hence modified afr_inode_refresh_done() to
support that.

If inode refresh failed on all children of afr due to ENOENT (say file
migrated by dht), it resets the readables to zero. Any inflight txn which
then later comes on the inode fails with EIO because no readable
children present for the inode.

Fix:
Don't update readables when inode refresh fails on *all* children of
afr. In that way any inflight txns will either proceed with its own inode
refresh if needed and fail it with the right errno or use the old value
of readables and continue with the txn.

Also, add quorum checks to the beginning of afr_transaction(). Otherwise, we
seem to be winding the lock and checking for quorum only in pre-op pahse.

Note: This should ideally fix BZ 1329505 since the stop gap fix for
it is has been reverted at https://review.gluster.org/#/c/20028.

Change-Id: I82990769f01be918a073fec83fc67ba4b3be24b1
BUG: 1599247
Signed-off-by: Ravishankar N <ravishankar@redhat.com>

1 files changed, 42 insertions, 16 deletions

diff --git a/xlators/cluster/afr/src/afr-common.c b/xlators/cluster/afr/src/afr-common.c
index 2e63030189a..0ffd59d65e2 100644
--- a/xlators/cluster/afr/src/afr-common.c
+++ b/xlators/cluster/afr/src/afr-common.c
@@ -1145,7 +1145,7 @@ afr_inode_refresh_err (call_frame_t *frame, xlator_t *this)
 
 	err = afr_final_errno (local, priv);
 ret:
-	return -err;
+	return err;
 }
 
 gf_boolean_t
@@ -1195,31 +1195,31 @@ afr_txn_refresh_done (call_frame_t *frame, xlator_t *this, int err)
         if (ret == -EIO || (local->is_read_txn && !event_generation)) {
                 /* No readable subvolume even after refresh ==> splitbrain.*/
                 if (!priv->fav_child_policy) {
-                        err = -EIO;
+                        err = EIO;
                         goto refresh_done;
                 }
                 read_subvol = afr_sh_get_fav_by_policy (this, local->replies,
                                                         inode, NULL);
                 if (read_subvol == -1) {
-                        err = -EIO;
+                        err = EIO;
                         goto refresh_done;
                 }
 
                 heal_frame = copy_frame (frame);
                 if (!heal_frame) {
-                        err = -EIO;
+                        err = EIO;
                         goto refresh_done;
                 }
                 heal_frame->root->pid = GF_CLIENT_PID_SELF_HEALD;
                 heal_local = AFR_FRAME_INIT (heal_frame, op_errno);
                 if (!heal_local) {
-                        err = -EIO;
+                        err = EIO;
                         AFR_STACK_DESTROY (heal_frame);
                         goto refresh_done;
                 }
                 heal_local->xdata_req = dict_new();
                 if (!heal_local->xdata_req) {
-                        err = -EIO;
+                        err = EIO;
                         AFR_STACK_DESTROY (heal_frame);
                         goto refresh_done;
                 }
@@ -1239,29 +1239,54 @@ refresh_done:
         return 0;
 }
 
+static void
+afr_fill_success_replies (afr_local_t *local, afr_private_t *priv,
+                          unsigned char *replies)
+{
+        int i = 0;
+
+        for (i = 0; i < priv->child_count; i++) {
+                if (local->replies[i].valid && local->replies[i].op_ret == 0)
+                        replies[i] = 1;
+        }
+}
+
 int
 afr_inode_refresh_done (call_frame_t *frame, xlator_t *this, int error)
 {
 	call_frame_t *heal_frame = NULL;
 	afr_local_t *local = NULL;
+        afr_private_t *priv = NULL;
         gf_boolean_t start_heal = _gf_false;
         afr_local_t *heal_local = NULL;
+        unsigned char *success_replies = NULL;
         int op_errno = ENOMEM;
 	int ret = 0;
-	int err = 0;
 
 	if (error != 0) {
-		err = error;
 		goto refresh_done;
 	}
 
 	local = frame->local;
+        priv = this->private;
+        success_replies = alloca0 (priv->child_count);
+        afr_fill_success_replies (local, priv, success_replies);
+
+        if (local->op == GF_FOP_LOOKUP ||
+            (local->is_read_txn && !priv->quorum_reads))
+                goto interpret;
 
+        if (!afr_has_quorum (success_replies, this)) {
+                error = afr_final_errno (frame->local, this->private);
+                if (!error)
+                        error = afr_quorum_errno(priv);
+                goto refresh_done;
+        }
+
+interpret:
 	ret = afr_replies_interpret (frame, this, local->refreshinode,
                                      &start_heal);
 
-	err = afr_inode_refresh_err (frame, this);
-
 	if (ret && afr_selfheal_enabled (this) && start_heal) {
                 heal_frame = copy_frame (frame);
                 if (!heal_frame)
@@ -1281,7 +1306,7 @@ afr_inode_refresh_done (call_frame_t *frame, xlator_t *this, int error)
         }
 
 refresh_done:
-        afr_txn_refresh_done (frame, this, err);
+        afr_txn_refresh_done (frame, this, error);
 
 	return 0;
 }
@@ -1295,7 +1320,7 @@ afr_inode_refresh_subvol_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
         int call_child = (long) cookie;
         int8_t need_heal = 1;
         int call_count = 0;
-        GF_UNUSED int ret = 0;
+        int ret = 0;
 
         local = frame->local;
         local->replies[call_child].valid = 1;
@@ -1318,7 +1343,8 @@ afr_inode_refresh_subvol_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
         call_count = afr_frame_return (frame);
         if (call_count == 0) {
                 afr_set_need_heal (this, local);
-		afr_inode_refresh_done (frame, this, 0);
+                ret = afr_inode_refresh_err (frame, this);
+		afr_inode_refresh_done (frame, this, ret);
         }
 
 }
@@ -2786,7 +2812,7 @@ afr_discover_done (call_frame_t *frame, xlator_t *this)
 {
         afr_private_t       *priv  = NULL;
         afr_local_t         *local = NULL;
-	int                 i = -1;
+        int                 i = -1;
 	int                 op_errno = 0;
 	int                 spb_choice = -1;
 	int                 read_subvol = -1;
@@ -2904,7 +2930,7 @@ afr_discover_do (call_frame_t *frame, xlator_t *this, int err)
 	priv = this->private;
 
 	if (err) {
-		local->op_errno = -err;
+		local->op_errno = err;
 		ret = -1;
 		goto out;
 	}
@@ -3019,7 +3045,7 @@ afr_lookup_do (call_frame_t *frame, xlator_t *this, int err)
 	priv = this->private;
 
 	if (err < 0) {
-		local->op_errno = -err;
+		local->op_errno = err;
 		ret = -1;
 		goto out;
 	}