btrfs: __add_reloc_root error push-up

This patch pushes kmalloc errors up to the caller and BUGs in the caller.

The BUG_ON for duplicate reloc tree root insertion is replaced with a
panic explaining the issue.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>

1 files changed, 16 insertions, 6 deletions

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index e5996ff8aaa4..974b0dfeffa3 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1221,14 +1221,15 @@ fail:
 /*
  * helper to add 'address of tree root -> reloc tree' mapping
  */
-static int __add_reloc_root(struct btrfs_root *root)
+static int __must_check __add_reloc_root(struct btrfs_root *root)
 {
         struct rb_node *rb_node;
         struct mapping_node *node;
         struct reloc_control *rc = root->fs_info->reloc_ctl;
 
         node = kmalloc(sizeof(*node), GFP_NOFS);
-        BUG_ON(!node);
+        if (!node)
+                return -ENOMEM;
 
         node->bytenr = root->node->start;
         node->data = root;
@@ -1237,7 +1238,12 @@ static int __add_reloc_root(struct btrfs_root *root)
         rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
                               node->bytenr, &node->rb_node);
         spin_unlock(&rc->reloc_root_tree.lock);
-        BUG_ON(rb_node);
+        if (rb_node) {
+                kfree(node);
+                btrfs_panic(root->fs_info, -EEXIST, "Duplicate root found "
+                            "for start=%llu while inserting into relocation "
+                            "tree\n");
+        }
 
         list_add_tail(&root->root_list, &rc->reloc_roots);
         return 0;
@@ -1353,6 +1359,7 @@ int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
         struct btrfs_root *reloc_root;
         struct reloc_control *rc = root->fs_info->reloc_ctl;
         int clear_rsv = 0;
+        int ret;
 
         if (root->reloc_root) {
                 reloc_root = root->reloc_root;
@@ -1372,7 +1379,8 @@ int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
         if (clear_rsv)
                 trans->block_rsv = NULL;
 
-        __add_reloc_root(reloc_root);
+        ret = __add_reloc_root(reloc_root);
+        BUG_ON(ret < 0);
         root->reloc_root = reloc_root;
         return 0;
 }
@@ -4226,7 +4234,8 @@ int btrfs_recover_relocation(struct btrfs_root *root)
                                        reloc_root->root_key.offset);
                 BUG_ON(IS_ERR(fs_root));
 
-                __add_reloc_root(reloc_root);
+                err = __add_reloc_root(reloc_root);
+                BUG_ON(err < 0);
                 fs_root->reloc_root = reloc_root;
         }
 
@@ -4428,7 +4437,8 @@ void btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
         reloc_root = create_reloc_root(trans, root->reloc_root,
                                        new_root->root_key.objectid);
 
-        __add_reloc_root(reloc_root);
+        ret = __add_reloc_root(reloc_root);
+        BUG_ON(ret < 0);
         new_root->reloc_root = reloc_root;
 
         if (rc->create_reloc_tree) {