ceph: fix intra strip unit length calculation
Commit 645a102581b3639836b17d147c35d574fd6e8267 fixes calculation of object
offset for layouts with multiple stripes per object. This updates the
calculation of the length written to take into account multiple stripes per
object.
Signed-off-by: Noah Watkins <noah@noahdesu.com>
Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/osdmap.c b/fs/ceph/osdmap.c
index 5a5520c..d62e111 100644
--- a/fs/ceph/osdmap.c
+++ b/fs/ceph/osdmap.c
@@ -731,7 +731,7 @@
u32 sc = le32_to_cpu(layout->fl_stripe_count);
u32 bl, stripeno, stripepos, objsetno;
u32 su_per_object;
- u64 t;
+ u64 t, su_offset;
dout("mapping %llu~%llu osize %u fl_su %u\n", off, *plen,
osize, su);
@@ -755,10 +755,15 @@
/* *oxoff = *off % layout->fl_stripe_unit; # offset in su */
t = off;
- *oxoff = do_div(t, su);
- *oxoff += (stripeno % su_per_object) * su;
+ su_offset = do_div(t, su);
+ *oxoff = su_offset + (stripeno % su_per_object) * su;
- *oxlen = min_t(u64, *plen, su - *oxoff);
+ /*
+ * 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;
dout(" obj extent %llu~%llu\n", *oxoff, *oxlen);