ceph: nuke startsync op

startsync is a no-op, has been for years.  Remove it.

Link: http://tracker.ceph.com/issues/20604
Signed-off-by: Yanhu Cao <gmayyyha@gmail.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/addr.c

@@ -752,21 +752,11 @@ static int ceph_writepages_start(struct address_space *mapping,
 	int rc = 0;
 	unsigned int wsize = i_blocksize(inode);
 	struct ceph_osd_request *req = NULL;
-	int do_sync = 0;
 	loff_t snap_size, i_size;
 	u64 truncate_size;
 	u32 truncate_seq;
 
-	/*
-	 * Include a 'sync' in the OSD request if this is a data
-	 * integrity write (e.g., O_SYNC write or fsync()), or if our
-	 * cap is being revoked.
-	 */
-	if ((wbc->sync_mode == WB_SYNC_ALL) ||
-		ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER))
-		do_sync = 1;
-	dout("writepages_start %p dosync=%d (mode=%s)\n",
-	     inode, do_sync,
+	dout("writepages_start %p (mode=%s)\n", inode,
 	     wbc->sync_mode == WB_SYNC_NONE ? "NONE" :
 	     (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD"));
 
@@ -936,7 +926,7 @@ get_more_pages:
 					break;
 				}
 
-				num_ops = 1 + do_sync;
+				num_ops = 1;
 				strip_unit_end = page->index +
 					((len - 1) >> PAGE_SHIFT);
 
@@ -1042,7 +1032,7 @@ new_request:
 		for (i = 0; i < locked_pages; i++) {
 			u64 cur_offset = page_offset(pages[i]);
 			if (offset + len != cur_offset) {
-				if (op_idx + do_sync + 1 == req->r_num_ops)
+				if (op_idx + 1 == req->r_num_ops)
 					break;
 				osd_req_op_extent_dup_last(req, op_idx,
 							   cur_offset - offset);
@@ -1079,17 +1069,12 @@ new_request:
 						 0, !!pool, false);
 		osd_req_op_extent_update(req, op_idx, len);
 
-		if (do_sync) {
-			op_idx++;
-			osd_req_op_init(req, op_idx, CEPH_OSD_OP_STARTSYNC, 0);
-		}
 		BUG_ON(op_idx + 1 != req->r_num_ops);
 
 		pool = NULL;
 		if (i < locked_pages) {
 			BUG_ON(num_ops <= req->r_num_ops);
 			num_ops -= req->r_num_ops;
-			num_ops += do_sync;
 			locked_pages -= i;
 
 			/* allocate new pages array for next request */

fs/ceph/file.c

@@ -800,7 +800,6 @@ static void ceph_aio_retry_work(struct work_struct *work)
 	}
 
 	req->r_ops[0] = orig_req->r_ops[0];
-	osd_req_op_init(req, 1, CEPH_OSD_OP_STARTSYNC, 0);
 
 	req->r_mtime = aio_req->mtime;
 	req->r_data_offset = req->r_ops[0].extent.offset;
@@ -874,8 +873,7 @@ ceph_direct_read_write(struct kiocb *iocb, struct iov_iter *iter,
 		vino = ceph_vino(inode);
 		req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
 					    vino, pos, &size, 0,
-					    /*include a 'startsync' command*/
-					    write ? 2 : 1,
+					    1,
 					    write ? CEPH_OSD_OP_WRITE :
 						    CEPH_OSD_OP_READ,
 					    flags, snapc,
@@ -927,7 +925,6 @@ ceph_direct_read_write(struct kiocb *iocb, struct iov_iter *iter,
 			truncate_inode_pages_range(inode->i_mapping, pos,
 					(pos+len) | (PAGE_SIZE - 1));
 
-			osd_req_op_init(req, 1, CEPH_OSD_OP_STARTSYNC, 0);
 			req->r_mtime = mtime;
 		}
 

include/linux/ceph/rados.h

@@ -230,7 +230,6 @@ extern const char *ceph_osd_state_name(int s);
 									    \
 	/* fancy write */						    \
 	f(APPEND,	__CEPH_OSD_OP(WR, DATA, 6),	"append")	    \
-	f(STARTSYNC,	__CEPH_OSD_OP(WR, DATA, 7),	"startsync")	    \
 	f(SETTRUNC,	__CEPH_OSD_OP(WR, DATA, 8),	"settrunc")	    \
 	f(TRIMTRUNC,	__CEPH_OSD_OP(WR, DATA, 9),	"trimtrunc")	    \
 									    \

net/ceph/osd_client.c

@@ -863,8 +863,6 @@ static u32 osd_req_encode_op(struct ceph_osd_op *dst,
 		dst->cls.method_len = src->cls.method_len;
 		dst->cls.indata_len = cpu_to_le32(src->cls.indata_len);
 		break;
-	case CEPH_OSD_OP_STARTSYNC:
-		break;
 	case CEPH_OSD_OP_WATCH:
 		dst->watch.cookie = cpu_to_le64(src->watch.cookie);
 		dst->watch.ver = cpu_to_le64(0);
@@ -916,9 +914,6 @@ static u32 osd_req_encode_op(struct ceph_osd_op *dst,
  * if the file was recently truncated, we include information about its
  * old and new size so that the object can be updated appropriately.  (we
  * avoid synchronously deleting truncated objects because it's slow.)
- *
- * if @do_sync, include a 'startsync' command so that the osd will flush
- * data quickly.
  */
 struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *osdc,
 					       struct ceph_file_layout *layout,