For every hardlink in btrfs, there is a corresponding inode back reference. All inode back references for hardlinks in a given directory are stored in single b-tree item. The size of b-tree item is limited by the size of b-tree leaf, so we can only create limited number of hardlinks to a given file in a directory.
The original code lacks of the check, it oops if the number of hardlinks goes over the limit. This patch fixes the issue by adding the check to btrfs_link and btrfs_rename. Signed-off-by: Yan Zheng <[email protected]> --- diff -urp 1/fs/btrfs/ctree.c 2/fs/btrfs/ctree.c --- 1/fs/btrfs/ctree.c 2009-07-29 10:03:04.150859426 +0800 +++ 2/fs/btrfs/ctree.c 2009-08-05 14:55:01.850810000 +0800 @@ -2853,6 +2853,12 @@ static noinline int split_leaf(struct bt int split; int num_doubles = 0; + l = path->nodes[0]; + slot = path->slots[0]; + if (extend && data_size + btrfs_item_size_nr(l, slot) + + sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root)) + return -EOVERFLOW; + /* first try to make some room by pushing left and right */ if (data_size && ins_key->type != BTRFS_DIR_ITEM_KEY) { wret = push_leaf_right(trans, root, path, data_size, 0); diff -urp 1/fs/btrfs/inode.c 2/fs/btrfs/inode.c --- 1/fs/btrfs/inode.c 2009-07-29 10:03:04.365858071 +0800 +++ 2/fs/btrfs/inode.c 2009-08-05 16:06:24.220810000 +0800 @@ -3674,7 +3674,7 @@ int btrfs_add_link(struct btrfs_trans_ha struct inode *parent_inode, struct inode *inode, const char *name, int name_len, int add_backref, u64 index) { - int ret; + int ret = 0; struct btrfs_key key; struct btrfs_root *root = BTRFS_I(parent_inode)->root; @@ -3682,18 +3682,18 @@ int btrfs_add_link(struct btrfs_trans_ha btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY); key.offset = 0; - ret = btrfs_insert_dir_item(trans, root, name, name_len, - parent_inode->i_ino, - &key, btrfs_inode_type(inode), - index); + if (add_backref) { + ret = btrfs_insert_inode_ref(trans, root, + name, name_len, inode->i_ino, + parent_inode->i_ino, index); + } + if (ret == 0) { - if (add_backref) { - ret = btrfs_insert_inode_ref(trans, root, - name, name_len, - inode->i_ino, - parent_inode->i_ino, - index); - } + ret = btrfs_insert_dir_item(trans, root, name, name_len, + parent_inode->i_ino, &key, + btrfs_inode_type(inode), index); + BUG_ON(ret); + btrfs_i_size_write(parent_inode, parent_inode->i_size + name_len * 2); parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME; @@ -3877,20 +3877,16 @@ static int btrfs_link(struct dentry *old atomic_inc(&inode->i_count); err = btrfs_add_nondir(trans, dentry, inode, 1, index); - - if (err) - drop_inode = 1; - - dir->i_sb->s_dirt = 1; - btrfs_update_inode_block_group(trans, dir); - err = btrfs_update_inode(trans, root, inode); - if (err) drop_inode = 1; + else { + dir->i_sb->s_dirt = 1; + btrfs_update_inode_block_group(trans, dir); + btrfs_update_inode(trans, root, inode); + btrfs_log_new_name(trans, inode, NULL, dentry->d_parent); + } nr = trans->blocks_used; - - btrfs_log_new_name(trans, inode, NULL, dentry->d_parent); btrfs_end_transaction_throttle(trans, root); fail: if (drop_inode) { @@ -4833,6 +4829,16 @@ static int btrfs_rename(struct inode *ol btrfs_set_trans_block_group(trans, new_dir); + ret = btrfs_set_inode_index(new_dir, &index); + if (ret) + goto out_fail; + + ret = btrfs_insert_inode_ref(trans, root, new_dentry->d_name.name, + new_dentry->d_name.len, old_inode->i_ino, + new_dir->i_ino, index); + if (ret) + goto out_fail; + btrfs_inc_nlink(old_dentry->d_inode); old_dir->i_ctime = old_dir->i_mtime = ctime; new_dir->i_ctime = new_dir->i_mtime = ctime; @@ -4844,8 +4850,7 @@ static int btrfs_rename(struct inode *ol ret = btrfs_unlink_inode(trans, root, old_dir, old_dentry->d_inode, old_dentry->d_name.name, old_dentry->d_name.len); - if (ret) - goto out_fail; + BUG_ON(ret); if (new_inode) { new_inode->i_ctime = CURRENT_TIME; @@ -4853,24 +4858,17 @@ static int btrfs_rename(struct inode *ol new_dentry->d_inode, new_dentry->d_name.name, new_dentry->d_name.len); - if (ret) - goto out_fail; + BUG_ON(ret); if (new_inode->i_nlink == 0) { ret = btrfs_orphan_add(trans, new_dentry->d_inode); - if (ret) - goto out_fail; + BUG_ON(ret); } - } - ret = btrfs_set_inode_index(new_dir, &index); - if (ret) - goto out_fail; ret = btrfs_add_link(trans, new_dentry->d_parent->d_inode, old_inode, new_dentry->d_name.name, - new_dentry->d_name.len, 1, index); - if (ret) - goto out_fail; + new_dentry->d_name.len, 0, index); + BUG_ON(ret); btrfs_log_new_name(trans, old_inode, old_dir, new_dentry->d_parent); diff -urp 1/fs/btrfs/inode-item.c 2/fs/btrfs/inode-item.c --- 1/fs/btrfs/inode-item.c 2009-07-24 09:51:38.372057017 +0800 +++ 2/fs/btrfs/inode-item.c 2009-08-05 15:11:37.141061000 +0800 @@ -149,6 +149,8 @@ int btrfs_insert_inode_ref(struct btrfs_ ptr = (unsigned long)(ref + 1); ret = 0; } else if (ret < 0) { + if (ret == -EOVERFLOW) + ret = -EMLINK; goto out; } else { ref = btrfs_item_ptr(path->nodes[0], path->slots[0], -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
