fs/ntfs3: Check possible errors in run_pack in advance

Checking in advance speeds things up in some cases.

Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

diff --git a/fs/ntfs3/run.c b/fs/ntfs3/run.c
index 4168b8a..987a150 100644 (file)
--- a/fs/ntfs3/run.c
+++ b/fs/ntfs3/run.c
@@ -820,26 +820,36 @@ int run_pack(const struct runs_tree *run, CLST svcn, CLST len, u8 *run_buf,
        CLST next_vcn, vcn, lcn;
        CLST prev_lcn = 0;
        CLST evcn1 = svcn + len;
+       const struct ntfs_run *r, *r_end;
        int packed_size = 0;
        size_t i;
-       bool ok;
        s64 dlcn;
        int offset_size, size_size, tmp;
 
-       next_vcn = vcn = svcn;
-
        *packed_vcns = 0;
 
        if (!len)
                goto out;
 
-       ok = run_lookup_entry(run, vcn, &lcn, &len, &i);
+       /* Check all required entries [svcn, encv1) available. */
+       if (!run_lookup(run, svcn, &i))
+               return -ENOENT;
 
-       if (!ok)
-               goto error;
+       r_end = run->runs + run->count;
+       r = run->runs + i;
 
-       if (next_vcn != vcn)
-               goto error;
+       for (next_vcn = r->vcn + r->len; next_vcn < evcn1;
+            next_vcn = r->vcn + r->len) {
+               if (++r >= r_end || r->vcn != next_vcn)
+                       return -ENOENT;
+       }
+
+       /* Repeat cycle above and pack runs. Assume no errors. */
+       r = run->runs + i;
+       len = svcn - r->vcn;
+       vcn = svcn;
+       lcn = r->lcn == SPARSE_LCN ? SPARSE_LCN : (r->lcn + len);
+       len = r->len - len;
 
        for (;;) {
                next_vcn = vcn + len;
@@ -888,12 +898,10 @@ int run_pack(const struct runs_tree *run, CLST svcn, CLST len, u8 *run_buf,
                if (packed_size + 1 >= run_buf_size || next_vcn >= evcn1)
                        goto out;
 
-               ok = run_get_entry(run, ++i, &vcn, &lcn, &len);
-               if (!ok)
-                       goto error;
-
-               if (next_vcn != vcn)
-                       goto error;
+               r += 1;
+               vcn = r->vcn;
+               lcn = r->lcn;
+               len = r->len;
        }
 
 out:
@@ -902,9 +910,6 @@ out:
                run_buf[0] = 0;
 
        return packed_size + 1;
-
-error:
-       return -EOPNOTSUPP;
 }
 
 /*