/**
* ntfs_cluster_write - write ntfs clusters
* @vol: volume to write to
* @lcn: starting logical cluster number
* @count: number of clusters to write
* @b: data buffer to write to disk
*
* Write @count ntfs clusters starting at logical cluster number @lcn from
* buffer @b to volume @vol. Return the number of clusters written or -1 on
* error, with errno set to the error code.
*/
s64 ntfs_cluster_write(const ntfs_volume *vol, const s64 lcn,
const s64 count, const void *b)
{
s64 bw;
if (!vol || lcn < 0 || count < 0) {
errno = EINVAL;
return -1;
}
if (vol->nr_clusters < lcn + count) {
errno = ESPIPE;
ntfs_log_perror("Trying to write outside of volume "
"(%lld < %lld)", (long long)vol->nr_clusters,
(long long)lcn + count);
return -1;
}
if (!NVolReadOnly(vol))
bw = ntfs_pwrite(vol->dev, lcn << vol->cluster_size_bits,
count << vol->cluster_size_bits, b);
else
bw = count << vol->cluster_size_bits;
if (bw < 0) {
ntfs_log_perror("Error writing cluster(s)");
return bw;
}
return bw >> vol->cluster_size_bits;
}
/**
* ntfs_mst_pwrite - multi sector transfer (mst) positioned write
* @dev: device to write to
* @pos: position in file descriptor to write to
* @count: number of blocks to write
* @bksize: size of each block that needs mst protecting
* @b: data buffer to write to disk
*
* Multi sector transfer (mst) positioned write. This function will write
* @count blocks of size @bksize bytes each from data buffer @b to the device
* @dev at position @pos.
*
* On success, return the number of successfully written blocks. If this number
* is lower than @count this means that the write has been interrupted or that
* an error was encountered during the write so that the write is partial. 0
* means nothing was written (also return 0 when @count or @bksize are 0).
*
* On error and nothing has been written, return -1 with errno set
* appropriately to the return code of either seek, write, or set
* to EINVAL in case of invalid arguments.
*
* NOTE: We mst protect the data, write it, then mst deprotect it using a quick
* deprotect algorithm (no checking). This saves us from making a copy before
* the write and at the same time causes the usn to be incremented in the
* buffer. This conceptually fits in better with the idea that cached data is
* always deprotected and protection is performed when the data is actually
* going to hit the disk and the cache is immediately deprotected again
* simulating an mst read on the written data. This way cache coherency is
* achieved.
*/
s64 ntfs_mst_pwrite(struct ntfs_device *dev, const s64 pos, s64 count,
const u32 bksize, void *b)
{
s64 written, i;
if (count < 0 || bksize % NTFS_BLOCK_SIZE) {
errno = EINVAL;
return -1;
}
if (!count)
return 0;
/* Prepare data for writing. */
for (i = 0; i < count; ++i) {
int err;
err = ntfs_mst_pre_write_fixup((NTFS_RECORD*)
((u8*)b + i * bksize), bksize);
if (err < 0) {
/* Abort write at this position. */
if (!i)
return err;
count = i;
break;
}
}
/* Write the prepared data. */
written = ntfs_pwrite(dev, pos, count * bksize, b);
/* Quickly deprotect the data again. */
for (i = 0; i < count; ++i)
ntfs_mst_post_write_fixup((NTFS_RECORD*)((u8*)b + i * bksize));
if (written <= 0)
return written;
/* Finally, return the number of complete blocks written. */
return written / bksize;
}
static int ntfs_inner_zero(ntfs_attr *na, runlist_element *rl)
{
ntfs_volume *vol;
char *buf;
runlist_element *zrl;
s64 cofs;
s64 pos;
s64 zeroed;
int err;
err = 0;
vol = na->ni->vol;
buf = (char*)malloc(vol->cluster_size);
if (buf) {
memset(buf, 0, vol->cluster_size);
zrl = rl;
pos = zrl->vcn << vol->cluster_size_bits;
while (zrl->length
&& !err
&& (pos < na->initialized_size)) {
for (cofs=0; cofs<zrl->length && !err; cofs++) {
zeroed = ntfs_pwrite(vol->dev,
(rl->lcn + cofs)
<< vol->cluster_size_bits,
vol->cluster_size, buf);
if (zeroed != vol->cluster_size) {
ntfs_log_error("Failed to zero at "
"offset %lld\n",
(long long)pos);
errno = EIO;
err = -1;
}
pos += vol->cluster_size;
}
zrl++;
pos = zrl->vcn << vol->cluster_size_bits;
}
free(buf);
} else {
ntfs_log_error("Failed to allocate memory\n");
errno = ENOSPC;
err = -1;
}
return (err);
}
static int change_serial(ntfs_volume *vol, u64 sector, le64 serial_number,
NTFS_BOOT_SECTOR *bs, NTFS_BOOT_SECTOR *oldbs)
{
int res;
le64 mask;
BOOL same;
res = -1;
if ((ntfs_pread(vol->dev, sector << vol->sector_size_bits,
vol->sector_size, bs) == vol->sector_size)) {
same = TRUE;
if (!sector)
/* save the real bootsector */
memcpy(oldbs, bs, vol->sector_size);
else
/* backup bootsector must be similar */
same = !memcmp(oldbs, bs, vol->sector_size);
if (same) {
if (opts.new_serial & 2)
bs->volume_serial_number = serial_number;
else {
mask = const_cpu_to_le64(~0x0ffffffffULL);
bs->volume_serial_number
= (serial_number & mask)
| (bs->volume_serial_number & ~mask);
}
if (opts.noaction
|| (ntfs_pwrite(vol->dev,
sector << vol->sector_size_bits,
vol->sector_size, bs) == vol->sector_size)) {
res = 0;
}
} else {
ntfs_log_info("* Warning : the backup boot sector"
" does not match (leaving unchanged)\n");
res = 0;
}
}
return (res);
}
