From: Yan, Zheng <zheng.z.yan@intel.com>
Date: Sun, 16 Feb 2014 14:14:50 +0000 (+0800)
Subject: ReplicatedPG: return no data if read size is trimmed to zero
X-Git-Tag: v0.78~170^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=refs%2Fpull%2F1251%2Fhead;p=ceph.git

ReplicatedPG: return no data if read size is trimmed to zero

OSD should return no data if the read size is trimmed to zero by the
truncate_seq/truncate_size check. We can't rely on ObjectStore::read()
to do that because it reads the entire object when the 'len' parameter
is zero.

Fixes: #7371
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
---

diff --git a/src/osd/ReplicatedPG.cc b/src/osd/ReplicatedPG.cc
index 826a7e9d39c..8de7e03249c 100644
--- a/src/osd/ReplicatedPG.cc
+++ b/src/osd/ReplicatedPG.cc
@@ -2829,22 +2829,25 @@ int ReplicatedPG::do_osd_ops(OpContext *ctx, vector<OSDOp>& ops)
     case CEPH_OSD_OP_READ:
       ++ctx->num_read;
       {
+	uint64_t trim = (uint64_t)-1;
 	__u32 seq = oi.truncate_seq;
 	// are we beyond truncate_size?
 	if ( (seq < op.extent.truncate_seq) &&
 	     (op.extent.offset + op.extent.length > op.extent.truncate_size) ) {
 
 	  // truncated portion of the read
-	  unsigned from = MAX(op.extent.offset, op.extent.truncate_size);  // also end of data
-	  unsigned to = op.extent.offset + op.extent.length;
-	  unsigned trim = to-from;
+	  uint64_t from = MAX(op.extent.offset, op.extent.truncate_size);  // also end of data
+	  uint64_t to = op.extent.offset + op.extent.length;
+	  trim = to - from;
 
 	  op.extent.length = op.extent.length - trim;
 	}
 
 	// read into a buffer
 	bufferlist bl;
-	if (pool.info.ec_pool()) {
+	if (trim != (uint64_t)-1 && op.extent.length == 0) {
+	  // read size was trimmed to zero
+	} else if (pool.info.ec_pool()) {
 	  ctx->pending_async_reads.push_back(
 	    make_pair(
 	      make_pair(op.extent.offset, op.extent.length),