/* truncate the file to the specified length */
static int ftruncate_internal(struct filestr_desc *file, file_size_t size,
bool write_now)
{
int rc = 0, rc2 = 1;
file_size_t cursize = *file->sizep;
file_size_t truncsize = MIN(size, cursize);
if (write_now)
{
unsigned long sector = filesize_sectors(truncsize);
struct filestr_cache *const cachep = file->stream.cachep;
if (cachep->flags == (FSC_NEW|FSC_DIRTY) &&
cachep->sector + 1 == sector)
{
/* sector created but may have never been added to the cluster
chain; flush it now or the subsequent may fail */
rc2 = flush_cache(file);
if (rc2 == FAT_RC_ENOSPC)
{
/* no space left on device; further truncation needed */
discard_cache(file);
truncsize = ALIGN_DOWN(truncsize - 1, SECTOR_SIZE);
sector--;
rc = rc2;
}
else if (rc2 < 0)
FILE_ERROR(ERRNO, rc2 * 10 - 1);
}
rc2 = fat_seek(&file->stream.fatstr, sector);
if (rc2 < 0)
FILE_ERROR(EIO, rc2 * 10 - 2);
rc2 = fat_truncate(&file->stream.fatstr);
if (rc2 < 0)
FILE_ERROR(EIO, rc2 * 10 - 3);
}
/* else just change the cached file size */
if (truncsize < cursize)
{
*file->sizep = truncsize;
fileop_ontruncate_internal(&file->stream);
}
/* if truncation was partially successful, it effectively destroyed
everything after the truncation point; still, indicate failure
after adjusting size */
if (rc2 == 0)
FILE_ERROR(EIO, -4);
else if (rc2 < 0)
FILE_ERROR(ERRNO, rc2);
file_error:
return rc;
}
/*
* Truncate a file to 0 length.
*/
static void UMSDOS_truncate (struct inode *inode)
{
Printk (("UMSDOS_truncate\n"));
if (!IS_RDONLY (inode)) {
fat_truncate (inode);
inode->i_ctime = inode->i_mtime = CURRENT_TIME;
mark_inode_dirty(inode);
}
}
