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>

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index e5996ff..974b0df 100644 (file)
--- 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) {