1 files changed, 76 insertions, 0 deletions

diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c
index 951ef09b82f4..6f0444473594 100644
--- a/fs/btrfs/export.c
+++ b/fs/btrfs/export.c
@@ -232,9 +232,85 @@ fail:
         return ERR_PTR(ret);
 }
 
+static int btrfs_get_name(struct dentry *parent, char *name,
+                          struct dentry *child)
+{
+        struct inode *inode = child->d_inode;
+        struct inode *dir = parent->d_inode;
+        struct btrfs_path *path;
+        struct btrfs_root *root = BTRFS_I(dir)->root;
+        struct btrfs_inode_ref *iref;
+        struct btrfs_root_ref *rref;
+        struct extent_buffer *leaf;
+        unsigned long name_ptr;
+        struct btrfs_key key;
+        int name_len;
+        int ret;
+
+        if (!dir || !inode)
+                return -EINVAL;
+
+        if (!S_ISDIR(dir->i_mode))
+                return -EINVAL;
+
+        path = btrfs_alloc_path();
+        if (!path)
+                return -ENOMEM;
+        path->leave_spinning = 1;
+
+        if (inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) {
+                key.objectid = BTRFS_I(inode)->root->root_key.objectid;
+                key.type = BTRFS_ROOT_BACKREF_KEY;
+                key.offset = (u64)-1;
+                root = root->fs_info->tree_root;
+        } else {
+                key.objectid = inode->i_ino;
+                key.offset = dir->i_ino;
+                key.type = BTRFS_INODE_REF_KEY;
+        }
+
+        ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+        if (ret < 0) {
+                btrfs_free_path(path);
+                return ret;
+        } else if (ret > 0) {
+                if (inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) {
+                        path->slots[0]--;
+                } else {
+                        btrfs_free_path(path);
+                        return -ENOENT;
+                }
+        }
+        leaf = path->nodes[0];
+
+        if (inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) {
+               rref = btrfs_item_ptr(leaf, path->slots[0],
+                                     struct btrfs_root_ref);
+               name_ptr = (unsigned long)(rref + 1);
+               name_len = btrfs_root_ref_name_len(leaf, rref);
+        } else {
+                iref = btrfs_item_ptr(leaf, path->slots[0],
+                                      struct btrfs_inode_ref);
+                name_ptr = (unsigned long)(iref + 1);
+                name_len = btrfs_inode_ref_name_len(leaf, iref);
+        }
+
+        read_extent_buffer(leaf, name, name_ptr, name_len);
+        btrfs_free_path(path);
+
+        /*
+         * have to add the null termination to make sure that reconnect_path
+         * gets the right len for strlen
+         */
+        name[name_len] = '\0';
+
+        return 0;
+}
+
 const struct export_operations btrfs_export_ops = {
         .encode_fh      = btrfs_encode_fh,
         .fh_to_dentry   = btrfs_fh_to_dentry,
         .fh_to_parent   = btrfs_fh_to_parent,
         .get_parent     = btrfs_get_parent,
+        .get_name       = btrfs_get_name,
 };