librbd: make read_iterate iterate over periods

Object sizes no longer make sense since we are iterating over the logical
device image space, and the striping may make that unrelated to the size
of the individual objects.

Signed-off-by: Sage Weil <sage@inktank.com>

diff --git a/src/librbd/internal.cc b/src/librbd/internal.cc
index cb88239ccfe5dc7078d9a46788892301a072b938..7cd077a26665932b2d6c9c00bc28833a0ebec92a 100644 (file)
--- a/src/librbd/internal.cc
+++ b/src/librbd/internal.cc
@@ -2099,16 +2099,14 @@ reprotect_and_return_err:
       return r;
 
     int64_t total_read = 0;
-    uint64_t start_block = get_block_num(ictx->order, off);
-    uint64_t end_block = get_block_num(ictx->order, off + len - 1);
-    uint64_t block_size = get_block_size(ictx->order);
+    uint64_t period = ictx->get_stripe_period();
     uint64_t left = len;
 
     start_time = ceph_clock_now(ictx->cct);
-    for (uint64_t i = start_block; i <= end_block; i++) {
-      uint64_t total_off = off + total_read;
-      uint64_t block_ofs = get_block_ofs(ictx->order, total_off);
-      uint64_t read_len = min(block_size - block_ofs, left);
+    while (left > 0) {
+      uint64_t period_off = off - (off % period);
+      uint64_t read_len = min(period_off + period - off, left);
+
       buffer::ptr bp(read_len);
       bufferlist bl;
       bl.append(bp);
@@ -2120,7 +2118,7 @@ reprotect_and_return_err:
 
       Context *ctx = new C_SafeCond(&mylock, &cond, &done, &ret);
       AioCompletion *c = aio_create_completion_internal(ctx, rbd_ctx_cb);
-      r = aio_read(ictx, total_off, read_len, bl.c_str(), c);
+      r = aio_read(ictx, off, read_len, bl.c_str(), c);
       if (r < 0) {
        c->release();
        delete ctx;
@@ -2142,6 +2140,7 @@ reprotect_and_return_err:
 
       total_read += ret;
       left -= ret;
+      off += ret;
     }
 
     elapsed = ceph_clock_now(ictx->cct) - start_time;