cluster/ec: add functions for stripe alignment

This patch removes old functions to align offsets and sizes
to stripe size boundaries and adds new ones to offer more
possibilities.

The new functions are:

 * ec_adjust_offset_down()
     Aligns a given offset to a multiple of the stripe size
     equal or smaller than the initial one. It returns the
     size of the gap between the aligned offset and the given
     one.

 * ec_adjust_offset_up()
     Aligns a given offset to a multiple of the stripe size
     equal or greater than the initial one. It returns the
     size of the skipped region between the given offset and
     the aligned one. If an overflow happens, the returned
     valid has negative sign (but correct value) and the
     offset is set to the maximum value (not aligned).

 * ec_adjust_size_down()
     Aligns the given size to a multiple of the stripe size
     equal or smaller than the initial one. It returns the
     size of the missed region between the aligned size and
     the given one.

 * ec_adjust_size_up()
     Aligns the given size to a multiple of the stripe size
     equal or greater than the initial one. It returns the
     size of the gap between the given size and the aligned
     one. If an overflow happens, the returned value has
     negative sign (but correct value) and the size is set
     to the maximum value (not aligned).

These functions have been defined in ec-helpers.h as static
inline since they are very small and compilers can optimize
them (specially the 'scale' argument).

Change-Id: I4c91009ad02f76c73772034dfde27ee1c78a80d7
Signed-off-by: Xavier Hernandez <jahernan@redhat.com>

1 files changed, 8 insertions, 5 deletions

diff --git a/xlators/cluster/ec/src/ec-inode-write.c b/xlators/cluster/ec/src/ec-inode-write.c
index 68bea1ae55b..3ed9b2a1ba4 100644
--- a/xlators/cluster/ec/src/ec-inode-write.c
+++ b/xlators/cluster/ec/src/ec-inode-write.c
@@ -870,8 +870,10 @@ int32_t ec_manager_fallocate(ec_fop_data_t *fop, int32_t state)
                 return EC_STATE_REPORT;
         }
         fop->user_size = fop->offset + fop->size;
-        fop->head = ec_adjust_offset (fop->xl->private, &fop->offset, 1);
-        fop->size = ec_adjust_size (fop->xl->private, fop->head + fop->size, 1);
+        fop->head = ec_adjust_offset_down (fop->xl->private, &fop->offset,
+                                           _gf_true);
+        fop->size += fop->head;
+        ec_adjust_size_up (fop->xl->private, &fop->size, _gf_true);
 
         /* Fall through */
 
@@ -1145,7 +1147,7 @@ int32_t ec_manager_truncate(ec_fop_data_t * fop, int32_t state)
     {
         case EC_STATE_INIT:
             fop->user_size = fop->offset;
-            fop->offset = ec_adjust_size(fop->xl->private, fop->offset, 1);
+            ec_adjust_offset_up(fop->xl->private, &fop->offset, _gf_true);
 
         /* Fall through */
 
@@ -1508,8 +1510,9 @@ ec_writev_prepare_buffers(ec_t *ec, ec_fop_data_t *fop)
     int32_t err;
 
     fop->user_size = iov_length(fop->vector, fop->int32);
-    fop->head = ec_adjust_offset(ec, &fop->offset, 0);
-    fop->size = ec_adjust_size(ec, fop->user_size + fop->head, 0);
+    fop->head = ec_adjust_offset_down(ec, &fop->offset, _gf_false);
+    fop->size = fop->user_size + fop->head;
+    ec_adjust_size_up(ec, &fop->size, _gf_false);
 
     if ((fop->int32 != 1) || (fop->head != 0) ||
         (fop->size > fop->user_size) ||