summaryrefslogtreecommitdiffstats
path: root/xlators/cluster/afr/src/afr-common.c
diff options
context:
space:
mode:
Diffstat (limited to 'xlators/cluster/afr/src/afr-common.c')
-rw-r--r--xlators/cluster/afr/src/afr-common.c67
1 files changed, 59 insertions, 8 deletions
diff --git a/xlators/cluster/afr/src/afr-common.c b/xlators/cluster/afr/src/afr-common.c
index 300ab92efaf..21a2be3dd6f 100644
--- a/xlators/cluster/afr/src/afr-common.c
+++ b/xlators/cluster/afr/src/afr-common.c
@@ -546,6 +546,10 @@ afr_is_read_child (int32_t *success_children, int32_t *sources,
gf_boolean_t success_child = _gf_false;
gf_boolean_t source = _gf_false;
+ if (child < 0) {
+ return _gf_false;
+ }
+
GF_ASSERT (success_children);
GF_ASSERT (child_count > 0);
@@ -562,13 +566,44 @@ out:
return (success_child && source);
}
+int32_t
+afr_hash_child (int32_t *success_children, int32_t child_count,
+ unsigned int hmode, uuid_t gfid)
+{
+ uuid_t gfid_copy = {0,};
+
+ if (!hmode) {
+ return -1;
+ }
+
+ if (gfid) {
+ uuid_copy(gfid_copy,gfid);
+ }
+ if (hmode > 1) {
+ /*
+ * Why getpid? Because it's one of the cheapest calls
+ * available - faster than gethostname etc. - and returns a
+ * constant-length value that's sure to be shorter than a UUID.
+ * It's still very unlikely to be the same across clients, so
+ * it still provides good mixing. We're not trying for
+ * perfection here. All we need is a low probability that
+ * multiple clients won't converge on the same subvolume.
+ */
+ *((pid_t *)gfid_copy) = getpid();
+ }
+
+ return SuperFastHash((char *)gfid_copy,
+ sizeof(gfid_copy)) % child_count;
+}
+
/* If sources is NULL the xattrs are assumed to be of source for all
* success_children.
*/
int
-afr_select_read_child_from_policy (int32_t *success_children, int32_t child_count,
- int32_t prev_read_child,
- int32_t config_read_child, int32_t *sources)
+afr_select_read_child_from_policy (int32_t *success_children,
+ int32_t child_count, int32_t prev_read_child,
+ int32_t config_read_child, int32_t *sources,
+ unsigned int hmode, uuid_t gfid)
{
int32_t read_child = -1;
int i = 0;
@@ -585,6 +620,13 @@ afr_select_read_child_from_policy (int32_t *success_children, int32_t child_coun
read_child))
goto out;
+ read_child = afr_hash_child (success_children, child_count,
+ hmode, gfid);
+ if (afr_is_read_child (success_children, sources, child_count,
+ read_child)) {
+ goto out;
+ }
+
for (i = 0; i < child_count; i++) {
read_child = success_children[i];
if (read_child < 0)
@@ -604,7 +646,7 @@ out:
void
afr_set_read_ctx_from_policy (xlator_t *this, inode_t *inode,
int32_t *fresh_children, int32_t prev_read_child,
- int32_t config_read_child)
+ int32_t config_read_child, uuid_t gfid)
{
int read_child = -1;
afr_private_t *priv = NULL;
@@ -614,7 +656,8 @@ afr_set_read_ctx_from_policy (xlator_t *this, inode_t *inode,
priv->child_count,
prev_read_child,
config_read_child,
- NULL);
+ NULL,
+ priv->hash_mode, gfid);
if (read_child >= 0)
afr_inode_set_read_ctx (this, inode, read_child,
fresh_children);
@@ -1271,6 +1314,7 @@ afr_lookup_select_read_child (afr_local_t *local, xlator_t *this,
dict_t **xattrs = NULL;
int32_t *success_children = NULL;
afr_transaction_type type = AFR_METADATA_TRANSACTION;
+ uuid_t *gfid = NULL;
GF_ASSERT (local);
GF_ASSERT (this);
@@ -1284,8 +1328,9 @@ afr_lookup_select_read_child (afr_local_t *local, xlator_t *this,
ia_type = local->cont.lookup.bufs[success_children[0]].ia_type;
type = afr_transaction_type_get (ia_type);
xattrs = local->cont.lookup.xattrs;
+ gfid = &local->cont.lookup.buf.ia_gfid;
source = afr_lookup_select_read_child_by_txn_type (this, local, xattrs,
- type);
+ type, *gfid);
if (source < 0) {
gf_log (this->name, GF_LOG_DEBUG, "failed to select source "
"for %s", local->loc.path);
@@ -2131,8 +2176,14 @@ afr_lookup (call_frame_t *frame, xlator_t *this,
} else {
LOCK (&priv->read_child_lock);
{
- local->read_child_index = (++priv->read_child_rr)
- % (priv->child_count);
+ if (priv->hash_mode) {
+ local->read_child_index = -1;
+ }
+ else {
+ local->read_child_index =
+ (++priv->read_child_rr) %
+ (priv->child_count);
+ }
}
UNLOCK (&priv->read_child_lock);
local->cont.lookup.fresh_lookup = _gf_true;