kmalloc a few large stack objects in the btrfs_ioctl path

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 14 insertions, 6 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 585f279d1112..7f764455f26e 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -80,10 +80,14 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
         int ret = 0;
         int level;
         struct btrfs_key first_key;
-        struct btrfs_root new_root;
+        struct btrfs_root *new_root;
 
-        memcpy(&new_root, root, sizeof(new_root));
-        new_root.root_key.objectid = new_root_objectid;
+        new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
+        if (!new_root)
+                return -ENOMEM;
+
+        memcpy(new_root, root, sizeof(*new_root));
+        new_root->root_key.objectid = new_root_objectid;
 
         WARN_ON(root->ref_cows && trans->transid !=
                 root->fs_info->running_transaction->transid);
@@ -99,12 +103,14 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
         } else {
                 first_key.objectid = 0;
         }
-        cow = __btrfs_alloc_free_block(trans, &new_root, buf->len,
+        cow = __btrfs_alloc_free_block(trans, new_root, buf->len,
                                        new_root_objectid,
                                        trans->transid, first_key.objectid,
                                        level, buf->start, 0);
-        if (IS_ERR(cow))
+        if (IS_ERR(cow)) {
+                kfree(new_root);
                 return PTR_ERR(cow);
+        }
 
         copy_extent_buffer(cow, buf, 0, 0, cow->len);
         btrfs_set_header_bytenr(cow, cow->start);
@@ -112,7 +118,9 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
         btrfs_set_header_owner(cow, new_root_objectid);
 
         WARN_ON(btrfs_header_generation(buf) > trans->transid);
-        ret = btrfs_inc_ref(trans, &new_root, buf);
+        ret = btrfs_inc_ref(trans, new_root, buf);
+        kfree(new_root);
+
         if (ret)
                 return ret;