ocfs2: silence -EEXIST from ocfs2_extent_map_insert/lookup

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c
index 1a5c69071df642afbe99a04ed348b33c955c9861..fcd4475d1f899754bb5ed61fa069b149a5e48c20 100644 (file)
--- a/fs/ocfs2/extent_map.c
+++ b/fs/ocfs2/extent_map.c
@@ -298,7 +298,7 @@ static int ocfs2_extent_map_find_leaf(struct inode *inode,
 
                ret = ocfs2_extent_map_insert(inode, rec,
                                              le16_to_cpu(el->l_tree_depth));
-               if (ret) {
+               if (ret && (ret != -EEXIST)) {
                        mlog_errno(ret);
                        goto out_free;
                }
@@ -427,6 +427,11 @@ static int ocfs2_extent_map_insert_entry(struct ocfs2_extent_map *em,
 /*
  * Simple rule: on any return code other than -EAGAIN, anything left
  * in the insert_context will be freed.
+ *
+ * Simple rule #2: A return code of -EEXIST from this function or
+ * its calls to ocfs2_extent_map_insert_entry() signifies that another
+ * thread beat us to the insert.  It is not an actual error, but it
+ * tells the caller we have no more work to do.
  */
 static int ocfs2_extent_map_try_insert(struct inode *inode,
                                       struct ocfs2_extent_rec *rec,
@@ -448,22 +453,32 @@ static int ocfs2_extent_map_try_insert(struct inode *inode,
                goto out_unlock;
        }
 
+       /* Since insert_entry failed, the map MUST have old_ent */
        old_ent = ocfs2_extent_map_lookup(em, le32_to_cpu(rec->e_cpos),
-                                         le32_to_cpu(rec->e_clusters), NULL,
-                                         NULL);
+                                         le32_to_cpu(rec->e_clusters),
+                                         NULL, NULL);
 
        BUG_ON(!old_ent);
 
-       ret = -EEXIST;
-       if (old_ent->e_tree_depth < tree_depth)
+       if (old_ent->e_tree_depth < tree_depth) {
+               /* Another thread beat us to the lower tree_depth */
+               ret = -EEXIST;
                goto out_unlock;
+       }
 
        if (old_ent->e_tree_depth == tree_depth) {
+               /*
+                * Another thread beat us to this tree_depth.
+                * Let's make sure we agree with that thread (the
+                * extent_rec should be identical).
+                */
                if (!memcmp(rec, &old_ent->e_rec,
                            sizeof(struct ocfs2_extent_rec)))
                        ret = 0;
+               else
+                       /* FIXME: Should this be ESRCH/EBADR??? */
+                       ret = -EEXIST;
 
-               /* FIXME: Should this be ESRCH/EBADR??? */
                goto out_unlock;
        }
 
@@ -599,7 +614,7 @@ static int ocfs2_extent_map_insert(struct inode *inode,
                                                  tree_depth, &ctxt);
        } while (ret == -EAGAIN);
 
-       if (ret < 0)
+       if ((ret < 0) && (ret != -EEXIST))
                mlog_errno(ret);
 
        if (ctxt.left_ent)