[bug report] ntfs3: Call ntfs_write_begin() and ntfs_write_end() directly

[bug report] ntfs3: Call ntfs_write_begin() and ntfs_write_end() directly

[Dan Carpenter]

Hello Matthew Wilcox (Oracle),

The patch 477323f1fc2e: "ntfs3: Call ntfs_write_begin() and
ntfs_write_end() directly" from Mar 3, 2022, leads to the following
Smatch static checker warning:

	fs/ntfs3/file.c:168 ntfs_extend_initialized_size()
	error: uninitialized symbol 'fsdata'.

fs/ntfs3/file.c
    115         for (;;) {
    116                 u32 zerofrom, len;
    117                 struct page *page;
    118                 void *fsdata;
    119                 u8 bits;
    120                 CLST vcn, lcn, clen;
    121 
    122                 if (is_sparsed(ni)) {
    123                         bits = sbi->cluster_bits;
    124                         vcn = pos >> bits;
    125 
    126                         err = attr_data_get_block(ni, vcn, 0, &lcn, &clen,
    127                                                   NULL);
    128                         if (err)
    129                                 goto out;
    130 
    131                         if (lcn == SPARSE_LCN) {
    132                                 loff_t vbo = (loff_t)vcn << bits;
    133                                 loff_t to = vbo + ((loff_t)clen << bits);
    134 
    135                                 if (to <= new_valid) {
    136                                         ni->i_valid = to;
    137                                         pos = to;
    138                                         goto next;
    139                                 }
    140 
    141                                 if (vbo < pos) {
    142                                         pos = vbo;
    143                                 } else {
    144                                         to = (new_valid >> bits) << bits;
    145                                         if (pos < to) {
    146                                                 ni->i_valid = to;
    147                                                 pos = to;
    148                                                 goto next;
    149                                         }
    150                                 }
    151                         }
    152                 }
    153 
    154                 zerofrom = pos & (PAGE_SIZE - 1);
    155                 len = PAGE_SIZE - zerofrom;
    156 
    157                 if (pos + len > new_valid)
    158                         len = new_valid - pos;
    159 
    160                 err = ntfs_write_begin(file, mapping, pos, len, &page, &fsdata);
    161                 if (err)
    162                         goto out;
    163 
    164                 zero_user_segment(page, zerofrom, PAGE_SIZE);
    165 
    166                 /* This function in any case puts page. */
    167                 err = ntfs_write_end(file, mapping, pos, len, len, page,
--> 168                                           fsdata);

"fsdata" is never initialized or used.

    169                 if (err < 0)
    170                         goto out;
    171                 pos += len;
    172 

regards,
dan carpenter