NTFS: Add an extra parameter @last_vcn to ntfs_get_size_for_mapping_pairs()
and ntfs_mapping_pairs_build() to allow the runlist encoding to be
partial which is desirable when filling holes in sparse attributes.
Update all callers.
Signed-off-by: Anton Altaparmakov <aia21@cantab.net>
diff --git a/fs/ntfs/runlist.c b/fs/ntfs/runlist.c
index 396d767..758855b 100644
--- a/fs/ntfs/runlist.c
+++ b/fs/ntfs/runlist.c
@@ -1048,10 +1048,17 @@
* ntfs_get_size_for_mapping_pairs - get bytes needed for mapping pairs array
* @vol: ntfs volume (needed for the ntfs version)
* @rl: locked runlist to determine the size of the mapping pairs of
- * @start_vcn: vcn at which to start the mapping pairs array
+ * @first_vcn: first vcn which to include in the mapping pairs array
+ * @last_vcn: last vcn which to include in the mapping pairs array
*
* Walk the locked runlist @rl and calculate the size in bytes of the mapping
- * pairs array corresponding to the runlist @rl, starting at vcn @start_vcn.
+ * pairs array corresponding to the runlist @rl, starting at vcn @first_vcn and
+ * finishing with vcn @last_vcn.
+ *
+ * A @last_vcn of -1 means end of runlist and in that case the size of the
+ * mapping pairs array corresponding to the runlist starting at vcn @first_vcn
+ * and finishing at the end of the runlist is determined.
+ *
* This for example allows us to allocate a buffer of the right size when
* building the mapping pairs array.
*
@@ -1067,34 +1074,50 @@
* remains locked throughout, and is left locked upon return.
*/
int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol,
- const runlist_element *rl, const VCN start_vcn)
+ const runlist_element *rl, const VCN first_vcn,
+ const VCN last_vcn)
{
LCN prev_lcn;
int rls;
+ BOOL the_end = FALSE;
- BUG_ON(start_vcn < 0);
+ BUG_ON(first_vcn < 0);
+ BUG_ON(last_vcn < -1);
+ BUG_ON(last_vcn >= 0 && first_vcn > last_vcn);
if (!rl) {
- BUG_ON(start_vcn);
+ BUG_ON(first_vcn);
+ BUG_ON(last_vcn > 0);
return 1;
}
- /* Skip to runlist element containing @start_vcn. */
- while (rl->length && start_vcn >= rl[1].vcn)
+ /* Skip to runlist element containing @first_vcn. */
+ while (rl->length && first_vcn >= rl[1].vcn)
rl++;
- if ((!rl->length && start_vcn > rl->vcn) || start_vcn < rl->vcn)
+ if (unlikely((!rl->length && first_vcn > rl->vcn) ||
+ first_vcn < rl->vcn))
return -EINVAL;
prev_lcn = 0;
/* Always need the termining zero byte. */
rls = 1;
/* Do the first partial run if present. */
- if (start_vcn > rl->vcn) {
- s64 delta;
+ if (first_vcn > rl->vcn) {
+ s64 delta, length = rl->length;
/* We know rl->length != 0 already. */
- if (rl->length < 0 || rl->lcn < LCN_HOLE)
+ if (unlikely(length < 0 || rl->lcn < LCN_HOLE))
goto err_out;
- delta = start_vcn - rl->vcn;
+ /*
+ * If @stop_vcn is given and finishes inside this run, cap the
+ * run length.
+ */
+ if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) {
+ s64 s1 = last_vcn + 1;
+ if (unlikely(rl[1].vcn > s1))
+ length = s1 - rl->vcn;
+ the_end = TRUE;
+ }
+ delta = first_vcn - rl->vcn;
/* Header byte + length. */
- rls += 1 + ntfs_get_nr_significant_bytes(rl->length - delta);
+ rls += 1 + ntfs_get_nr_significant_bytes(length - delta);
/*
* If the logical cluster number (lcn) denotes a hole and we
* are on NTFS 3.0+, we don't store it at all, i.e. we need
@@ -1102,9 +1125,9 @@
* Note: this assumes that on NTFS 1.2-, holes are stored with
* an lcn of -1 and not a delta_lcn of -1 (unless both are -1).
*/
- if (rl->lcn >= 0 || vol->major_ver < 3) {
+ if (likely(rl->lcn >= 0 || vol->major_ver < 3)) {
prev_lcn = rl->lcn;
- if (rl->lcn >= 0)
+ if (likely(rl->lcn >= 0))
prev_lcn += delta;
/* Change in lcn. */
rls += ntfs_get_nr_significant_bytes(prev_lcn);
@@ -1113,11 +1136,23 @@
rl++;
}
/* Do the full runs. */
- for (; rl->length; rl++) {
- if (rl->length < 0 || rl->lcn < LCN_HOLE)
+ for (; rl->length && !the_end; rl++) {
+ s64 length = rl->length;
+
+ if (unlikely(length < 0 || rl->lcn < LCN_HOLE))
goto err_out;
+ /*
+ * If @stop_vcn is given and finishes inside this run, cap the
+ * run length.
+ */
+ if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) {
+ s64 s1 = last_vcn + 1;
+ if (unlikely(rl[1].vcn > s1))
+ length = s1 - rl->vcn;
+ the_end = TRUE;
+ }
/* Header byte + length. */
- rls += 1 + ntfs_get_nr_significant_bytes(rl->length);
+ rls += 1 + ntfs_get_nr_significant_bytes(length);
/*
* If the logical cluster number (lcn) denotes a hole and we
* are on NTFS 3.0+, we don't store it at all, i.e. we need
@@ -1125,7 +1160,7 @@
* Note: this assumes that on NTFS 1.2-, holes are stored with
* an lcn of -1 and not a delta_lcn of -1 (unless both are -1).
*/
- if (rl->lcn >= 0 || vol->major_ver < 3) {
+ if (likely(rl->lcn >= 0 || vol->major_ver < 3)) {
/* Change in lcn. */
rls += ntfs_get_nr_significant_bytes(rl->lcn -
prev_lcn);
@@ -1168,7 +1203,7 @@
i = 0;
do {
- if (dst > dst_max)
+ if (unlikely(dst > dst_max))
goto err_out;
*dst++ = l & 0xffll;
l >>= 8;
@@ -1177,12 +1212,12 @@
j = (n >> 8 * (i - 1)) & 0xff;
/* If the sign bit is wrong, we need an extra byte. */
if (n < 0 && j >= 0) {
- if (dst > dst_max)
+ if (unlikely(dst > dst_max))
goto err_out;
i++;
*dst = (s8)-1;
} else if (n > 0 && j < 0) {
- if (dst > dst_max)
+ if (unlikely(dst > dst_max))
goto err_out;
i++;
*dst = (s8)0;
@@ -1198,13 +1233,18 @@
* @dst: destination buffer to which to write the mapping pairs array
* @dst_len: size of destination buffer @dst in bytes
* @rl: locked runlist for which to build the mapping pairs array
- * @start_vcn: vcn at which to start the mapping pairs array
+ * @first_vcn: first vcn which to include in the mapping pairs array
+ * @last_vcn: last vcn which to include in the mapping pairs array
* @stop_vcn: first vcn outside destination buffer on success or -ENOSPC
*
* Create the mapping pairs array from the locked runlist @rl, starting at vcn
- * @start_vcn and save the array in @dst. @dst_len is the size of @dst in
- * bytes and it should be at least equal to the value obtained by calling
- * ntfs_get_size_for_mapping_pairs().
+ * @first_vcn and finishing with vcn @last_vcn and save the array in @dst.
+ * @dst_len is the size of @dst in bytes and it should be at least equal to the
+ * value obtained by calling ntfs_get_size_for_mapping_pairs().
+ *
+ * A @last_vcn of -1 means end of runlist and in that case the mapping pairs
+ * array corresponding to the runlist starting at vcn @first_vcn and finishing
+ * at the end of the runlist is created.
*
* If @rl is NULL, just write a single terminator byte to @dst.
*
@@ -1213,7 +1253,7 @@
* been filled with all the mapping pairs that will fit, thus it can be treated
* as partial success, in that a new attribute extent needs to be created or
* the next extent has to be used and the mapping pairs build has to be
- * continued with @start_vcn set to *@stop_vcn.
+ * continued with @first_vcn set to *@stop_vcn.
*
* Return 0 on success and -errno on error. The following error codes are
* defined:
@@ -1227,27 +1267,32 @@
*/
int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst,
const int dst_len, const runlist_element *rl,
- const VCN start_vcn, VCN *const stop_vcn)
+ const VCN first_vcn, const VCN last_vcn, VCN *const stop_vcn)
{
LCN prev_lcn;
s8 *dst_max, *dst_next;
int err = -ENOSPC;
+ BOOL the_end = FALSE;
s8 len_len, lcn_len;
- BUG_ON(start_vcn < 0);
+ BUG_ON(first_vcn < 0);
+ BUG_ON(last_vcn < -1);
+ BUG_ON(last_vcn >= 0 && first_vcn > last_vcn);
BUG_ON(dst_len < 1);
if (!rl) {
- BUG_ON(start_vcn);
+ BUG_ON(first_vcn);
+ BUG_ON(last_vcn > 0);
if (stop_vcn)
*stop_vcn = 0;
/* Terminator byte. */
*dst = 0;
return 0;
}
- /* Skip to runlist element containing @start_vcn. */
- while (rl->length && start_vcn >= rl[1].vcn)
+ /* Skip to runlist element containing @first_vcn. */
+ while (rl->length && first_vcn >= rl[1].vcn)
rl++;
- if ((!rl->length && start_vcn > rl->vcn) || start_vcn < rl->vcn)
+ if (unlikely((!rl->length && first_vcn > rl->vcn) ||
+ first_vcn < rl->vcn))
return -EINVAL;
/*
* @dst_max is used for bounds checking in
@@ -1256,17 +1301,27 @@
dst_max = dst + dst_len - 1;
prev_lcn = 0;
/* Do the first partial run if present. */
- if (start_vcn > rl->vcn) {
- s64 delta;
+ if (first_vcn > rl->vcn) {
+ s64 delta, length = rl->length;
/* We know rl->length != 0 already. */
- if (rl->length < 0 || rl->lcn < LCN_HOLE)
+ if (unlikely(length < 0 || rl->lcn < LCN_HOLE))
goto err_out;
- delta = start_vcn - rl->vcn;
+ /*
+ * If @stop_vcn is given and finishes inside this run, cap the
+ * run length.
+ */
+ if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) {
+ s64 s1 = last_vcn + 1;
+ if (unlikely(rl[1].vcn > s1))
+ length = s1 - rl->vcn;
+ the_end = TRUE;
+ }
+ delta = first_vcn - rl->vcn;
/* Write length. */
len_len = ntfs_write_significant_bytes(dst + 1, dst_max,
- rl->length - delta);
- if (len_len < 0)
+ length - delta);
+ if (unlikely(len_len < 0))
goto size_err;
/*
* If the logical cluster number (lcn) denotes a hole and we
@@ -1277,19 +1332,19 @@
* case on NT4. - We assume that we just need to write the lcn
* change until someone tells us otherwise... (AIA)
*/
- if (rl->lcn >= 0 || vol->major_ver < 3) {
+ if (likely(rl->lcn >= 0 || vol->major_ver < 3)) {
prev_lcn = rl->lcn;
- if (rl->lcn >= 0)
+ if (likely(rl->lcn >= 0))
prev_lcn += delta;
/* Write change in lcn. */
lcn_len = ntfs_write_significant_bytes(dst + 1 +
len_len, dst_max, prev_lcn);
- if (lcn_len < 0)
+ if (unlikely(lcn_len < 0))
goto size_err;
} else
lcn_len = 0;
dst_next = dst + len_len + lcn_len + 1;
- if (dst_next > dst_max)
+ if (unlikely(dst_next > dst_max))
goto size_err;
/* Update header byte. */
*dst = lcn_len << 4 | len_len;
@@ -1299,13 +1354,25 @@
rl++;
}
/* Do the full runs. */
- for (; rl->length; rl++) {
- if (rl->length < 0 || rl->lcn < LCN_HOLE)
+ for (; rl->length && !the_end; rl++) {
+ s64 length = rl->length;
+
+ if (unlikely(length < 0 || rl->lcn < LCN_HOLE))
goto err_out;
+ /*
+ * If @stop_vcn is given and finishes inside this run, cap the
+ * run length.
+ */
+ if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) {
+ s64 s1 = last_vcn + 1;
+ if (unlikely(rl[1].vcn > s1))
+ length = s1 - rl->vcn;
+ the_end = TRUE;
+ }
/* Write length. */
len_len = ntfs_write_significant_bytes(dst + 1, dst_max,
- rl->length);
- if (len_len < 0)
+ length);
+ if (unlikely(len_len < 0))
goto size_err;
/*
* If the logical cluster number (lcn) denotes a hole and we
@@ -1316,17 +1383,17 @@
* case on NT4. - We assume that we just need to write the lcn
* change until someone tells us otherwise... (AIA)
*/
- if (rl->lcn >= 0 || vol->major_ver < 3) {
+ if (likely(rl->lcn >= 0 || vol->major_ver < 3)) {
/* Write change in lcn. */
lcn_len = ntfs_write_significant_bytes(dst + 1 +
len_len, dst_max, rl->lcn - prev_lcn);
- if (lcn_len < 0)
+ if (unlikely(lcn_len < 0))
goto size_err;
prev_lcn = rl->lcn;
} else
lcn_len = 0;
dst_next = dst + len_len + lcn_len + 1;
- if (dst_next > dst_max)
+ if (unlikely(dst_next > dst_max))
goto size_err;
/* Update header byte. */
*dst = lcn_len << 4 | len_len;