Convert ceph_calc_file_object_mapping() so it uses 64-bit variables
and divide operators. This is in anticipation of the next patch,
to keep the the changes it incurs more focused.
I made most of the variable names more verbose, and because it now
uses do_div() some of the calculations get done in a different
order. Net result is that the code does what it did before, but it
looks quite a bit different...
Signed-off-by: Alex Elder <elder@xxxxxxxxxxxxx>
---
net/ceph/osdmap.c | 112
+++++++++++++++++++++++++++++++++--------------------
1 files changed, 70 insertions(+), 42 deletions(-)
diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index f5f6e41..26c30e7 100644
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -933,59 +933,87 @@ bad:
/*
- * calculate file layout from given offset, length.
- * fill in correct oid, logical length, and object extent
- * offset, length.
+ * calculate file layout from given offset, length. fill in correct
+ * object number, logical length, and object extent offset and length.
*
- * for now, we write only a single su, until we can
- * pass a stride back to the caller.
+ * for now, we write only a single stripe_unit, until we can pass a
+ * stride back to the caller.
*/
void ceph_calc_file_object_mapping(struct ceph_file_layout *layout,
- u64 off, u64 *plen,
- u64 *ono,
- u64 *oxoff, u64 *oxlen)
+ u64 off,
+ u64 *plen,
+ u64 *object_num,
+ u64 *object_ext_off,
+ u64 *object_ext_len)
{
- u32 osize = (u32) ceph_file_layout_object_size(layout);
- u32 su = (u32) ceph_file_layout_stripe_unit(layout);
- u32 sc = (u32) ceph_file_layout_stripe_count(layout);
- u32 bl, stripeno, stripepos, objsetno;
- u32 su_per_object;
- u64 t, su_offset;
-
- dout("mapping %llu~%llu osize %u fl_su %u\n", off, *plen,
- osize, su);
- su_per_object = osize / su;
- dout("osize %u / su %u = su_per_object %u\n", osize, su,
- su_per_object);
-
- BUG_ON((su & ~PAGE_MASK) != 0);
- /* bl = *off / su; */
- t = off;
- do_div(t, su);
- bl = t;
- dout("off %llu / su %u = bl %u\n", off, su, bl);
-
- stripeno = bl / sc;
- stripepos = bl % sc;
- objsetno = stripeno / su_per_object;
-
- *ono = objsetno * sc + stripepos;
- dout("objset %u * sc %u = ono %u\n", objsetno, sc, (unsigned)*ono);
-
- /* *oxoff = *off % layout->fl_stripe_unit; # offset in su */
- t = off;
- su_offset = do_div(t, su);
- *oxoff = su_offset + (stripeno % su_per_object) * su;
+ u64 object_size = (u64) ceph_file_layout_object_size(layout);
+ u64 stripe_unit = (u64) ceph_file_layout_stripe_unit(layout);
+ u64 stripe_count = (u64) ceph_file_layout_stripe_count(layout);
+ u64 stripe_unit_per_object;
+ u64 stripe_unit_num;
+ u64 stripe_unit_offset;
+ u64 stripe_num;
+ u64 stripe_pos; /* Which object within an object set */
+ u64 obj_set_num;
+ u64 obj_stripe_unit_num; /* Which stripe_unit within object */
+
+ BUG_ON((stripe_unit & ~PAGE_MASK) != 0);
+
+ dout("mapping %llu~%llu object_size %llu fl_stripe_unit %llu\n",
+ off, *plen, object_size, stripe_unit);
+
+ /* stripe_unit_per_object = object_size / stripe_unit; */
+ stripe_unit_per_object = object_size;
+ do_div(stripe_unit_per_object, stripe_unit);
+ dout("object_size %llu / stripe_unit %llu "
+ "= stripe_unit_per_object %llu\n",
+ object_size, stripe_unit, stripe_unit_per_object);
+
+ /*
+ * stripe_unit_num = off / stripe_unit;
+ * stripe_unit_offset = off % stripe_unit;
+ */
+ stripe_unit_num = off;
+ stripe_unit_offset = do_div(stripe_unit_num, stripe_unit);
+ dout("off %llu / stripe_unit %llu = "
+ "stripe_unit_num %llu rem stripe_unit_offset = %llu\n",
+ off, stripe_unit, stripe_unit_num, stripe_unit_offset);
+
+ /*
+ * stripe_num = stripe_unit_num / stripe_count;
+ * stripe_pos = stripe_unit_num % stripe_count;
+ */
+ stripe_num = stripe_unit_num;
+ stripe_pos = do_div(stripe_num, stripe_count);
+ dout("stripe_unit_num %llu / stripe_count %llu = "
+ "stripe_num %llu rem stripe_pos %llu\n",
+ stripe_unit_num, stripe_count, stripe_num, stripe_pos);
+
+ /*
+ * obj_set_num = stripe_num / stripe_unit_per_object;
+ * obj_stripe_unit_num = stripe_num % stripe_unit_per_object;
+ */
+ obj_set_num = stripe_num;
+ obj_stripe_unit_num = do_div(obj_set_num, stripe_unit_per_object);
+
+ *object_num = obj_set_num * stripe_count + stripe_pos;
+ dout("obj_set_num %llu * stripe_count %llu = object_num %llu\n",
+ obj_set_num, stripe_count, *object_num);
+ *object_ext_off = stripe_unit * obj_stripe_unit_num
+ + stripe_unit_offset;
+ dout("obj_stripe_unit_num %llu * stripe_unit %llu = "
+ "object_ext_off %llu\n",
+ obj_stripe_unit_num, stripe_unit, *object_ext_off);
/*
* Calculate the length of the extent being written to the selected
* object. This is the minimum of the full length requested (plen) or
* the remainder of the current stripe being written to.
*/
- *oxlen = min_t(u64, *plen, su - su_offset);
- *plen = *oxlen;
+ *object_ext_len = min_t(u64, *plen, stripe_unit - stripe_unit_offset);
+ *plen = *object_ext_len;
- dout(" obj extent %llu~%llu\n", *oxoff, *oxlen);
+ dout(" obj extent %llu~%llu\n", *object_ext_off, *object_ext_len);
}
EXPORT_SYMBOL(ceph_calc_file_object_mapping);
--
1.7.5.4
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