ceph: fix fallocate division

We need to use do_div to divide by a 64-bit value.

Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

1 files changed, 10 insertions, 6 deletions

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 68af489c2abd..d5e12f580671 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -960,13 +960,17 @@ static int ceph_zero_objects(struct inode *inode, loff_t offset, loff_t length)
 {
         int ret = 0;
         struct ceph_inode_info *ci = ceph_inode(inode);
-        __s32 stripe_unit = ceph_file_layout_su(ci->i_layout);
-        __s32 stripe_count = ceph_file_layout_stripe_count(ci->i_layout);
-        __s32 object_size = ceph_file_layout_object_size(ci->i_layout);
-        loff_t object_set_size = (loff_t)object_size * stripe_count;
+        s32 stripe_unit = ceph_file_layout_su(ci->i_layout);
+        s32 stripe_count = ceph_file_layout_stripe_count(ci->i_layout);
+        s32 object_size = ceph_file_layout_object_size(ci->i_layout);
+        u64 object_set_size = object_size * stripe_count;
+        u64 nearly, t;
+
+        /* round offset up to next period boundary */
+        nearly = offset + object_set_size - 1;
+        t = nearly;
+        nearly -= do_div(t, object_set_size);
 
-        loff_t nearly = (offset + object_set_size - 1)
-                        / object_set_size * object_set_size;
         while (length && offset < nearly) {
                 loff_t size = length;
                 ret = ceph_zero_partial_object(inode, offset, &size);