[kdave-btrfs-devel:for-next-20220401 96/102] fs/btrfs/sysfs.c:830 btrfs_force_chunk_alloc_store() warn: passing zero to 'PTR_ERR'

[Dan Carpenter]

tree:   https://github.com/kdave/btrfs-devel.git for-next-20220401
head:   0c593f04d2f520a720c5c618ba9fe0355d08bba8
commit: 6e115adef2b6a9b9a7cc25414e1b8f4414e02044 [96/102] btrfs: add force_chunk_alloc sysfs entry to force allocation
config: nios2-randconfig-m031-20220403 (https://download.01.org/0day-ci/archive/20220403/202204030841.qWK5rMDU-lkp@xxxxxxxxx/config)
compiler: nios2-linux-gcc (GCC) 11.2.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

New smatch warnings:
fs/btrfs/sysfs.c:830 btrfs_force_chunk_alloc_store() warn: passing zero to 'PTR_ERR'

vim +/PTR_ERR +830 fs/btrfs/sysfs.c

6e115adef2b6a9 Stefan Roesch 2021-12-03  797  static ssize_t btrfs_force_chunk_alloc_store(struct kobject *kobj,
6e115adef2b6a9 Stefan Roesch 2021-12-03  798  					     struct kobj_attribute *a,
6e115adef2b6a9 Stefan Roesch 2021-12-03  799  					     const char *buf, size_t len)
6e115adef2b6a9 Stefan Roesch 2021-12-03  800  {
6e115adef2b6a9 Stefan Roesch 2021-12-03  801  	struct btrfs_space_info *space_info = to_space_info(kobj);
6e115adef2b6a9 Stefan Roesch 2021-12-03  802  	struct btrfs_fs_info *fs_info = to_fs_info(get_btrfs_kobj(kobj));
6e115adef2b6a9 Stefan Roesch 2021-12-03  803  	struct btrfs_trans_handle *trans;
6e115adef2b6a9 Stefan Roesch 2021-12-03  804  	unsigned long val;
6e115adef2b6a9 Stefan Roesch 2021-12-03  805  	int ret;
6e115adef2b6a9 Stefan Roesch 2021-12-03  806  
6e115adef2b6a9 Stefan Roesch 2021-12-03  807  	if (!fs_info) {
6e115adef2b6a9 Stefan Roesch 2021-12-03  808  		pr_err("couldn't get fs_info\n");
6e115adef2b6a9 Stefan Roesch 2021-12-03  809  		return -EPERM;
6e115adef2b6a9 Stefan Roesch 2021-12-03  810  	}
6e115adef2b6a9 Stefan Roesch 2021-12-03  811  
6e115adef2b6a9 Stefan Roesch 2021-12-03  812  	if (!capable(CAP_SYS_ADMIN))
6e115adef2b6a9 Stefan Roesch 2021-12-03  813  		return -EPERM;
6e115adef2b6a9 Stefan Roesch 2021-12-03  814  
6e115adef2b6a9 Stefan Roesch 2021-12-03  815  	if (sb_rdonly(fs_info->sb))
6e115adef2b6a9 Stefan Roesch 2021-12-03  816  		return -EROFS;
6e115adef2b6a9 Stefan Roesch 2021-12-03  817  
6e115adef2b6a9 Stefan Roesch 2021-12-03  818  	ret = kstrtoul(buf, 10, &val);
6e115adef2b6a9 Stefan Roesch 2021-12-03  819  	if (ret)
6e115adef2b6a9 Stefan Roesch 2021-12-03  820  		return ret;
6e115adef2b6a9 Stefan Roesch 2021-12-03  821  
6e115adef2b6a9 Stefan Roesch 2021-12-03  822  	if (val == 0)
6e115adef2b6a9 Stefan Roesch 2021-12-03  823  		return -EINVAL;
6e115adef2b6a9 Stefan Roesch 2021-12-03  824  
6e115adef2b6a9 Stefan Roesch 2021-12-03  825  	/*
6e115adef2b6a9 Stefan Roesch 2021-12-03  826  	 * Allocate new chunk.
6e115adef2b6a9 Stefan Roesch 2021-12-03  827  	 */
6e115adef2b6a9 Stefan Roesch 2021-12-03  828  	trans = btrfs_start_transaction(fs_info->tree_root, 0);
6e115adef2b6a9 Stefan Roesch 2021-12-03  829  	if (!trans)
6e115adef2b6a9 Stefan Roesch 2021-12-03 @830  		return PTR_ERR(trans);

PTR(NULL) is success.

6e115adef2b6a9 Stefan Roesch 2021-12-03  831  	ret = btrfs_force_chunk_alloc(trans, space_info->flags);
6e115adef2b6a9 Stefan Roesch 2021-12-03  832  	btrfs_end_transaction(trans);
6e115adef2b6a9 Stefan Roesch 2021-12-03  833  
6e115adef2b6a9 Stefan Roesch 2021-12-03  834  	if (ret == 1)
6e115adef2b6a9 Stefan Roesch 2021-12-03  835  		return len;
6e115adef2b6a9 Stefan Roesch 2021-12-03  836  
6e115adef2b6a9 Stefan Roesch 2021-12-03  837  	return -ENOSPC;
6e115adef2b6a9 Stefan Roesch 2021-12-03  838  }

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