[bug report] fs/ntfs3: Add attrib operations

[Dan Carpenter <error27@gmail.com>]

Hello Konstantin Komarov,

Commit be71b5cba2e6 ("fs/ntfs3: Add attrib operations") from Aug 13,
2021 (linux-next), leads to the following Smatch static checker
warning:

	fs/ntfs3/attrib.c:176 attr_allocate_clusters()
	error: we previously assumed 'pre_alloc' could be null (see line 167)

fs/ntfs3/attrib.c
    160 int attr_allocate_clusters(struct ntfs_sb_info *sbi, struct runs_tree *run,
    161                            struct runs_tree *run_da, CLST vcn, CLST lcn,
    162                            CLST len, CLST *pre_alloc, enum ALLOCATE_OPT opt,
    163                            CLST *alen, const size_t fr, CLST *new_lcn,
    164                            CLST *new_len)
    165 {
    166         int err;
    167         CLST flen, vcn0 = vcn, pre = pre_alloc ? *pre_alloc : 0;
    168         size_t cnt = run->count;
    169 
    170         for (;;) {
    171                 err = ntfs_look_for_free_space(sbi, lcn, len + pre, &lcn, &flen,
    172                                                opt);
    173 
    174                 if (err == -ENOSPC && pre) {
    175                         pre = 0;
--> 176                         if (*pre_alloc)

I'm not sure why warnings from 2021 are showing up as new warnings but
presumably this should be:

	if (pre_alloc)
		*pre_alloc = 0;

    177                                 *pre_alloc = 0;
    178                         continue;
    179                 }
    180 
    181                 if (err == -ENOSPC && new_len && vcn - vcn0) {
    182                         /* Keep already allocated clusters. */
    183                         *alen = vcn - vcn0;

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regards,
dan carpenter