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>

5 files changed, 132 insertions, 60 deletions

diff --git a/fs/ntfs/ChangeLog b/fs/ntfs/ChangeLog
index aff749db314c..67994c9c248f 100644
--- a/fs/ntfs/ChangeLog
+++ b/fs/ntfs/ChangeLog
@@ -135,6 +135,10 @@ ToDo/Notes:
         - Change the runlist terminator of the newly allocated cluster(s) to
           LCN_ENOENT in ntfs_attr_make_non_resident().  Otherwise the runlist
           code gets confused.
+        - 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.
 
 2.1.22 - Many bug and race fixes and error handling improvements.
 
diff --git a/fs/ntfs/attrib.c b/fs/ntfs/attrib.c
index 34ea405b883d..c6b2bb64d651 100644
--- a/fs/ntfs/attrib.c
+++ b/fs/ntfs/attrib.c
@@ -1317,7 +1317,7 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni)
                 page = NULL;
         }
         /* Determine the size of the mapping pairs array. */
-        mp_size = ntfs_get_size_for_mapping_pairs(vol, rl, 0);
+        mp_size = ntfs_get_size_for_mapping_pairs(vol, rl, 0, -1);
         if (unlikely(mp_size < 0)) {
                 err = mp_size;
                 ntfs_debug("Failed to get size for mapping pairs array, error "
@@ -1416,7 +1416,7 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni)
                         cpu_to_sle64(attr_size);
         /* Generate the mapping pairs array into the attribute record. */
         err = ntfs_mapping_pairs_build(vol, (u8*)a + mp_ofs,
-                        arec_size - mp_ofs, rl, 0, NULL);
+                        arec_size - mp_ofs, rl, 0, -1, NULL);
         if (unlikely(err)) {
                 ntfs_debug("Failed to build mapping pairs, error code %i.",
                                 err);
diff --git a/fs/ntfs/mft.c b/fs/ntfs/mft.c
index 61ce09f1b652..3d0ba8e60adc 100644
--- a/fs/ntfs/mft.c
+++ b/fs/ntfs/mft.c
@@ -1407,7 +1407,7 @@ static int ntfs_mft_bitmap_extend_allocation_nolock(ntfs_volume *vol)
         BUG_ON(ll < rl2->vcn);
         BUG_ON(ll >= rl2->vcn + rl2->length);
         /* Get the size for the new mapping pairs array for this extent. */
-        mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, ll);
+        mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, ll, -1);
         if (unlikely(mp_size <= 0)) {
                 ntfs_error(vol->sb, "Get size for mapping pairs failed for "
                                 "mft bitmap attribute extent.");
@@ -1441,7 +1441,7 @@ static int ntfs_mft_bitmap_extend_allocation_nolock(ntfs_volume *vol)
         /* Generate the mapping pairs array directly into the attr record. */
         ret = ntfs_mapping_pairs_build(vol, (u8*)a +
                         le16_to_cpu(a->data.non_resident.mapping_pairs_offset),
-                        mp_size, rl2, ll, NULL);
+                        mp_size, rl2, ll, -1, NULL);
         if (unlikely(ret)) {
                 ntfs_error(vol->sb, "Failed to build mapping pairs array for "
                                 "mft bitmap attribute.");
@@ -1529,7 +1529,7 @@ undo_alloc:
                                 a->data.non_resident.mapping_pairs_offset),
                                 old_alen - le16_to_cpu(
                                 a->data.non_resident.mapping_pairs_offset),
-                                rl2, ll, NULL)) {
+                                rl2, ll, -1, NULL)) {
                         ntfs_error(vol->sb, "Failed to restore mapping pairs "
                                         "array.%s", es);
                         NVolSetErrors(vol);
@@ -1838,7 +1838,7 @@ static int ntfs_mft_data_extend_allocation_nolock(ntfs_volume *vol)
         BUG_ON(ll < rl2->vcn);
         BUG_ON(ll >= rl2->vcn + rl2->length);
         /* Get the size for the new mapping pairs array for this extent. */
-        mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, ll);
+        mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, ll, -1);
         if (unlikely(mp_size <= 0)) {
                 ntfs_error(vol->sb, "Get size for mapping pairs failed for "
                                 "mft data attribute extent.");
@@ -1877,7 +1877,7 @@ static int ntfs_mft_data_extend_allocation_nolock(ntfs_volume *vol)
         /* Generate the mapping pairs array directly into the attr record. */
         ret = ntfs_mapping_pairs_build(vol, (u8*)a +
                         le16_to_cpu(a->data.non_resident.mapping_pairs_offset),
-                        mp_size, rl2, ll, NULL);
+                        mp_size, rl2, ll, -1, NULL);
         if (unlikely(ret)) {
                 ntfs_error(vol->sb, "Failed to build mapping pairs array of "
                                 "mft data attribute.");
@@ -1959,7 +1959,7 @@ undo_alloc:
                                 a->data.non_resident.mapping_pairs_offset),
                                 old_alen - le16_to_cpu(
                                 a->data.non_resident.mapping_pairs_offset),
-                                rl2, ll, NULL)) {
+                                rl2, ll, -1, NULL)) {
                         ntfs_error(vol->sb, "Failed to restore mapping pairs "
                                         "array.%s", es);
                         NVolSetErrors(vol);
diff --git a/fs/ntfs/runlist.c b/fs/ntfs/runlist.c
index 396d767c2cab..758855b0414e 100644
--- a/fs/ntfs/runlist.c
+++ b/fs/ntfs/runlist.c
@@ -1048,10 +1048,17 @@ static inline int ntfs_get_nr_significant_bytes(const s64 n)
  * 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 @@ static inline int ntfs_get_nr_significant_bytes(const s64 n)
  *          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;