From 37707cc321e79b46c796b09590e6b384e1b9f3f6 Mon Sep 17 00:00:00 2001
From: Mark Tinguely <tinguely@sgi.com>
Date: Tue, 4 Dec 2012 17:18:04 -0600
Subject: [PATCH] --- yaml --- r: 352910 b: refs/heads/master c:
 820a554f2f83d21f7e9e608377c8c86af70917bd h: refs/heads/master v: v3

---
 [refs]                      |  2 +-
 trunk/fs/xfs/xfs_buf_item.c | 20 +++++++++++++++-----
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/[refs] b/[refs]
index 36d433efb1b2..b3dc47daf394 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b94381737e9c4d014a4003e8ece9ba88670a2dd4
+refs/heads/master: 820a554f2f83d21f7e9e608377c8c86af70917bd
diff --git a/trunk/fs/xfs/xfs_buf_item.c b/trunk/fs/xfs/xfs_buf_item.c
index 1975b3d9007a..c48e60bd857d 100644
--- a/trunk/fs/xfs/xfs_buf_item.c
+++ b/trunk/fs/xfs/xfs_buf_item.c
@@ -287,6 +287,17 @@ xfs_buf_item_format_segment(
 	 */
 	base_size = offsetof(struct xfs_buf_log_format, blf_data_map) +
 			(blfp->blf_map_size * sizeof(blfp->blf_data_map[0]));
+
+	nvecs = 0;
+	first_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size, 0);
+	if (!(bip->bli_flags & XFS_BLI_STALE) && first_bit == -1) {
+		/*
+		 * If the map is not be dirty in the transaction, mark
+		 * the size as zero and do not advance the vector pointer.
+		 */
+		goto out;
+	}
+
 	vecp->i_addr = blfp;
 	vecp->i_len = base_size;
 	vecp->i_type = XLOG_REG_TYPE_BFORMAT;
@@ -301,15 +312,13 @@ xfs_buf_item_format_segment(
 		 */
 		trace_xfs_buf_item_format_stale(bip);
 		ASSERT(blfp->blf_flags & XFS_BLF_CANCEL);
-		blfp->blf_size = nvecs;
-		return vecp;
+		goto out;
 	}
 
 	/*
 	 * Fill in an iovec for each set of contiguous chunks.
 	 */
-	first_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size, 0);
-	ASSERT(first_bit != -1);
+
 	last_bit = first_bit;
 	nbits = 1;
 	for (;;) {
@@ -371,7 +380,8 @@ xfs_buf_item_format_segment(
 			nbits++;
 		}
 	}
-	bip->__bli_format.blf_size = nvecs;
+out:
+	blfp->blf_size = nvecs;
 	return vecp;
 }