cluster/afr: Set the self-heal "source" as read subvolume even when not doing self-heal.

This patch sets the read-subvolume equal to the self-heal "source"
even if we're not doing self-heal (because some one else is already
doing it).

Signed-off-by: Vikas Gorur <vikas@gluster.com>
Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 320 (Improve self-heal performance)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=320

5 files changed, 117 insertions, 29 deletions

diff --git a/xlators/cluster/afr/src/afr-self-heal-common.c b/xlators/cluster/afr/src/afr-self-heal-common.c
index a8160f4e2..327cab032 100644
--- a/xlators/cluster/afr/src/afr-self-heal-common.c
+++ b/xlators/cluster/afr/src/afr-self-heal-common.c
@@ -364,10 +364,13 @@ afr_sh_mark_if_size_differs (afr_self_heal_t *sh, int child_count)
 
         for (i = 0; i < child_count; i++) {
                 for (j = 0; j < child_count; j++) {
+                        if (!sh->buf)
+                                break;
+
                         if (SIZE_DIFFERS (&sh->buf[i], &sh->buf[j])
                             && (pending_matrix[i][j] == 0)
                             && (pending_matrix[j][i] == 0)) {
-                                
+
                                 pending_matrix[i][j] = 1;
                                 pending_matrix[j][i] = 1;
 
@@ -387,7 +390,7 @@ afr_sh_mark_biggest_fool_as_source (afr_self_heal_t *sh,
 {
         int i = 0;
         int biggest = 0;
-        
+
         for (i = 0; i < child_count; i++) {
                 if (characters[i].type == AFR_NODE_FOOL) {
                         biggest = i;
@@ -398,7 +401,10 @@ afr_sh_mark_biggest_fool_as_source (afr_self_heal_t *sh,
         for (i = 0; i < child_count; i++) {
                 if (characters[i].type != AFR_NODE_FOOL)
                         continue;
-                
+
+                if (!sh->buf)
+                        break;
+
                 if (SIZE_GREATER (&sh->buf[i], &sh->buf[biggest])) {
                         biggest = i;
                 }
@@ -417,6 +423,9 @@ afr_sh_mark_biggest_as_source (afr_self_heal_t *sh, int child_count)
         int i;
 
         for (i = 0; i < child_count; i++) {
+                if (!sh->buf)
+                        break;
+
                 if (SIZE_GREATER (&sh->buf[i], &sh->buf[biggest])) {
                         biggest = i;
                 }
diff --git a/xlators/cluster/afr/src/afr-self-heal-data.c b/xlators/cluster/afr/src/afr-self-heal-data.c
index 66a424902..eb0ee9b20 100644
--- a/xlators/cluster/afr/src/afr-self-heal-data.c
+++ b/xlators/cluster/afr/src/afr-self-heal-data.c
@@ -742,6 +742,38 @@ afr_sh_data_fix (call_frame_t *frame, xlator_t *this)
 
 
 int
+afr_self_heal_get_source (xlator_t *this, afr_local_t *local, dict_t **xattr)
+{
+	afr_self_heal_t *sh   = NULL;
+	afr_private_t   *priv = NULL;
+
+	int              nsources = 0;
+	int              source = 0;
+	int              i = 0;
+
+	sh   = &local->self_heal;
+	priv = this->private;
+
+	sh->pending_matrix = CALLOC (sizeof (int32_t *), priv->child_count);
+	for (i = 0; i < priv->child_count; i++) {
+		sh->pending_matrix[i] = CALLOC (sizeof (int32_t),
+						priv->child_count);
+	}
+	sh->sources      = CALLOC (priv->child_count, sizeof (*sh->sources));
+
+	afr_sh_build_pending_matrix (priv, sh->pending_matrix, xattr,
+				     priv->child_count, AFR_DATA_TRANSACTION);
+
+	nsources = afr_sh_mark_sources (sh, priv->child_count,
+                                        AFR_SELF_HEAL_DATA);
+
+	source = afr_sh_select_source (sh->sources, priv->child_count);
+
+	return source;
+}
+
+
+int
 afr_sh_data_fstat_cbk (call_frame_t *frame, void *cookie,
                        xlator_t *this, int32_t op_ret, int32_t op_errno,
                        struct stat *buf)
diff --git a/xlators/cluster/afr/src/afr-self-heal.h b/xlators/cluster/afr/src/afr-self-heal.h
index 3c8b1333e..1c2743a48 100644
--- a/xlators/cluster/afr/src/afr-self-heal.h
+++ b/xlators/cluster/afr/src/afr-self-heal.h
@@ -46,6 +46,9 @@ int
 afr_self_heal_metadata (call_frame_t *frame, xlator_t *this);
 
 int
+afr_self_heal_get_source (xlator_t *this, afr_local_t *local, dict_t **xattr);
+
+int
 afr_self_heal (call_frame_t *frame, xlator_t *this);
 
 #endif /* __AFR_SELF_HEAL_H__ */
diff --git a/xlators/cluster/afr/src/afr.c b/xlators/cluster/afr/src/afr.c
index 98eaeb6dd..9448dc4e6 100644
--- a/xlators/cluster/afr/src/afr.c
+++ b/xlators/cluster/afr/src/afr.c
@@ -332,8 +332,20 @@ afr_local_cleanup (afr_local_t *local, xlator_t *this)
 	FREE (local->child_up);
 
 	{ /* lookup */
-		if (local->cont.lookup.xattr)
-			dict_unref (local->cont.lookup.xattr);
+                if (local->cont.lookup.xattrs) {
+                        for (i = 0; i < priv->child_count; i++) {
+                                if (local->cont.lookup.xattrs[i]) {
+                                        dict_unref (local->cont.lookup.xattrs[i]);
+                                        local->cont.lookup.xattrs[i] = NULL;
+                                }
+                        }
+                        FREE (local->cont.lookup.xattrs);
+                        local->cont.lookup.xattrs = NULL;
+                }
+
+		if (local->cont.lookup.xattr) {
+                        dict_unref (local->cont.lookup.xattr);
+                }
 	}
 
 	{ /* getxattr */
@@ -559,6 +571,9 @@ afr_lookup_self_heal_check (afr_local_t *local, struct stat *buf,
 static void
 afr_lookup_done (call_frame_t *frame, xlator_t *this, struct stat *lookup_buf)
 {
+        int unwind = 1;
+        int source = -1;
+
         afr_local_t *local = NULL;
 
         local = frame->local;
@@ -597,25 +612,44 @@ afr_lookup_done (call_frame_t *frame, xlator_t *this, struct stat *lookup_buf)
         if ((local->self_heal.need_metadata_self_heal
              || local->self_heal.need_data_self_heal
              || local->self_heal.need_entry_self_heal)
-            && (!local->open_fd_count &&
-                !local->inodelk_count &&
-                !local->entrylk_count)
             && ((!local->cont.lookup.is_revalidate)
                 || (local->op_ret != -1))) {
 
-                if (!local->cont.lookup.inode->st_mode) {
-                        /* fix for RT #602 */
-                        local->cont.lookup.inode->st_mode =
-                                lookup_buf->st_mode;
-                }
+                if (local->open_fd_count
+                    || local->inodelk_count
+                    || local->entrylk_count) {
 
-                local->self_heal.background = _gf_true;
-                local->self_heal.mode       = local->cont.lookup.buf.st_mode;
-                local->self_heal.unwind     = afr_self_heal_lookup_unwind;
+                        /* Someone else is doing self-heal on this file.
+                           So just make a best effort to set the read-subvolume
+                           and return */
 
-                afr_self_heal (frame, this);
+                        if (S_ISREG (local->cont.lookup.inode->st_mode)) {
+                                source = afr_self_heal_get_source (this, local, local->cont.lookup.xattrs);
 
-        } else {
+                                if (source >= 0) {
+                                        afr_set_read_child (this,
+                                                            local->cont.lookup.inode,
+                                                            source);
+                                }
+                        }
+                } else {
+                        if (!local->cont.lookup.inode->st_mode) {
+                                /* fix for RT #602 */
+                                local->cont.lookup.inode->st_mode =
+                                        lookup_buf->st_mode;
+                        }
+
+                        local->self_heal.background = _gf_true;
+                        local->self_heal.mode       = local->cont.lookup.buf.st_mode;
+                        local->self_heal.unwind     = afr_self_heal_lookup_unwind;
+
+                        unwind = 0;
+
+                        afr_self_heal (frame, this);
+                }
+        }
+
+        if (unwind) {
                 AFR_STACK_UNWIND (lookup, frame, local->op_ret,
                                   local->op_errno,
                                   local->cont.lookup.inode, 
@@ -705,9 +739,10 @@ afr_fresh_lookup_cbk (call_frame_t *frame, void *cookie,
                         if (local->op_errno != ESTALE)
                                 local->op_ret = op_ret;
 
-			local->cont.lookup.inode = inode;
-			local->cont.lookup.xattr = dict_ref (xattr);
-                        local->cont.lookup.postparent = *postparent;
+			local->cont.lookup.inode               = inode;
+			local->cont.lookup.xattr               = dict_ref (xattr);
+			local->cont.lookup.xattrs[child_index] = dict_ref (xattr);
+                        local->cont.lookup.postparent          = *postparent;
 
                         *lookup_buf = *buf;
 
@@ -735,9 +770,11 @@ afr_fresh_lookup_cbk (call_frame_t *frame, void *cookie,
                                 if (local->cont.lookup.xattr)
                                         dict_unref (local->cont.lookup.xattr);
 
-                                local->cont.lookup.inode = inode;
                                 local->cont.lookup.xattr = dict_ref (xattr);
-                                local->cont.lookup.postparent = *postparent;
+
+                                local->cont.lookup.inode               = inode;
+                                local->cont.lookup.xattrs[child_index] = dict_ref (xattr);
+                                local->cont.lookup.postparent          = *postparent;
 
                                 *lookup_buf = *buf;
 
@@ -830,9 +867,10 @@ afr_revalidate_lookup_cbk (call_frame_t *frame, void *cookie,
                         if (local->op_errno != ESTALE)
                                 local->op_ret = op_ret;
 
-			local->cont.lookup.inode = inode;
-			local->cont.lookup.xattr = dict_ref (xattr);
-                        local->cont.lookup.postparent = *postparent;
+			local->cont.lookup.inode               = inode;
+			local->cont.lookup.xattr               = dict_ref (xattr);
+			local->cont.lookup.xattrs[child_index] = dict_ref (xattr);
+                        local->cont.lookup.postparent          = *postparent;
 
 			*lookup_buf = *buf;
 
@@ -859,12 +897,14 @@ afr_revalidate_lookup_cbk (call_frame_t *frame, void *cookie,
                                    lookup has succeeded on the read child.
                                    So use its inode number
                                 */
+
                                 if (local->cont.lookup.xattr)
                                         dict_unref (local->cont.lookup.xattr);
 
-                                local->cont.lookup.inode = inode;
-                                local->cont.lookup.xattr = dict_ref (xattr);
-                                local->cont.lookup.postparent = *postparent;
+                                local->cont.lookup.inode               = inode;
+                                local->cont.lookup.xattr               = dict_ref (xattr);
+                                local->cont.lookup.xattrs[child_index] = dict_ref (xattr);
+                                local->cont.lookup.postparent          = *postparent;
 
                                 *lookup_buf = *buf;
 
@@ -950,6 +990,9 @@ afr_lookup (call_frame_t *frame, xlator_t *this,
 
 	local->child_up = memdup (priv->child_up, priv->child_count);
 
+        local->cont.lookup.xattrs = CALLOC (priv->child_count,
+                                            sizeof (*local->cont.lookup.xattr));
+
 	local->call_count = afr_up_children_count (priv->child_count,
                                                    local->child_up);
         call_count = local->call_count;
diff --git a/xlators/cluster/afr/src/afr.h b/xlators/cluster/afr/src/afr.h
index 09f76351a..bf07a89d7 100644
--- a/xlators/cluster/afr/src/afr.h
+++ b/xlators/cluster/afr/src/afr.h
@@ -257,6 +257,7 @@ typedef struct _afr_local {
                         uint64_t gen;
                         ino_t parent_ino;
 			dict_t *xattr;
+			dict_t **xattrs;
                         gf_boolean_t is_revalidate;
 		} lookup;