ext4: start searching for the right extent from the goal group.

With mballoc we search for the best extent using different
criteria. We should always use the goal group when we are
starting with a new criteria.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NMingming Cao <cmm@us.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

fs/ext4/mballoc.c

@@ -1736,10 +1736,6 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
 		ac->ac_g_ex.fe_start = sbi->s_mb_last_start;
 		spin_unlock(&sbi->s_md_lock);
 	}
-
-	/* searching for the right group start from the goal value specified */
-	group = ac->ac_g_ex.fe_group;
-
 	/* Let's just scan groups to find more-less suitable blocks */
 	cr = ac->ac_2order ? 0 : 1;
 	/*
@@ -1749,6 +1745,12 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
 repeat:
 	for (; cr < 4 && ac->ac_status == AC_STATUS_CONTINUE; cr++) {
 		ac->ac_criteria = cr;
+		/*
+		 * searching for the right group start
+		 * from the goal value specified
+		 */
+		group = ac->ac_g_ex.fe_group;
+
 		for (i = 0; i < EXT4_SB(sb)->s_groups_count; group++, i++) {
 			struct ext4_group_info *grp;
 			struct ext4_group_desc *desc;