exofs: Fix groups code when num_devices is not divisible by group_width

There is a bug when num_devices is not divisible by group_width * mirrors.
We would not return to the proper device and offset when looping on to the
next group.

The fix makes code simpler actually.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>

1 files changed, 5 insertions, 17 deletions

diff --git a/fs/exofs/ios.c b/fs/exofs/ios.c
index 5bb47373c7e0..5a1960500c8a 100644
--- a/fs/exofs/ios.c
+++ b/fs/exofs/ios.c
@@ -305,8 +305,6 @@ int exofs_check_io(struct exofs_io_state *ios, u64 *resid)
 struct _striping_info {
         u64 obj_offset;
         u64 group_length;
-        u64 total_group_length;
-        u64 Major;
         unsigned dev;
         unsigned unit_off;
 };
@@ -343,8 +341,6 @@ static void _calc_stripe_info(struct exofs_io_state *ios, u64 file_offset,
                                   (M * group_depth * stripe_unit);
 
         si->group_length = T - H;
-        si->total_group_length = T;
-        si->Major = M;
 }
 
 static int _add_stripe_unit(struct exofs_io_state *ios,  unsigned *cur_pg,
@@ -450,17 +446,15 @@ out:
 static int _prepare_for_striping(struct exofs_io_state *ios)
 {
         u64 length = ios->length;
+        u64 offset = ios->offset;
         struct _striping_info si;
-        unsigned devs_in_group = ios->layout->group_width *
-                                 ios->layout->mirrors_p1;
         int ret = 0;
 
-        _calc_stripe_info(ios, ios->offset, &si);
-
         if (!ios->pages) {
                 if (ios->kern_buff) {
                         struct exofs_per_dev_state *per_dev = &ios->per_dev[0];
 
+                        _calc_stripe_info(ios, ios->offset, &si);
                         per_dev->offset = si.obj_offset;
                         per_dev->dev = si.dev;
 
@@ -474,6 +468,8 @@ static int _prepare_for_striping(struct exofs_io_state *ios)
         }
 
         while (length) {
+                _calc_stripe_info(ios, offset, &si);
+
                 if (length < si.group_length)
                         si.group_length = length;
 
@@ -481,16 +477,8 @@ static int _prepare_for_striping(struct exofs_io_state *ios)
                 if (unlikely(ret))
                         goto out;
 
+                offset += si.group_length;
                 length -= si.group_length;
-
-                si.group_length = si.total_group_length;
-                si.unit_off = 0;
-                ++si.Major;
-                si.obj_offset = si.Major * ios->layout->stripe_unit *
-                                                ios->layout->group_depth;
-
-                si.dev = (si.dev - (si.dev % devs_in_group)) + devs_in_group;
-                si.dev %= ios->layout->s_numdevs;
         }
 
 out: