From a04c46c9c4289e5b88906b8a44af1419725d2404 Mon Sep 17 00:00:00 2001
From: Josh Durgin <josh.durgin@dreamhost.com>
Date: Tue, 15 Nov 2011 14:49:53 -0800
Subject: [PATCH] --- yaml --- r: 276636 b: refs/heads/master c:
 81e759fbf7715514c32e563789db1d9d47fd55fb h: refs/heads/master v: v3

---
 [refs]                    |  2 +-
 trunk/drivers/block/rbd.c | 11 ++++++++++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 2174045f82dc..73ed5cce26e4 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 2151937d7ce491bfbe269a1ae742c6686904474c
+refs/heads/master: 81e759fbf7715514c32e563789db1d9d47fd55fb
diff --git a/trunk/drivers/block/rbd.c b/trunk/drivers/block/rbd.c
index 65cc424359b0..a828c6a276a8 100644
--- a/trunk/drivers/block/rbd.c
+++ b/trunk/drivers/block/rbd.c
@@ -461,6 +461,10 @@ static int rbd_header_from_disk(struct rbd_image_header *header,
 	u32 snap_count = le32_to_cpu(ondisk->snap_count);
 	int ret = -ENOMEM;
 
+	if (memcmp(ondisk, RBD_HEADER_TEXT, sizeof(RBD_HEADER_TEXT))) {
+		return -ENXIO;
+	}
+
 	init_rwsem(&header->snap_rwsem);
 	header->snap_names_len = le64_to_cpu(ondisk->snap_names_len);
 	header->snapc = kmalloc(sizeof(struct ceph_snap_context) +
@@ -1610,8 +1614,13 @@ static int rbd_read_header(struct rbd_device *rbd_dev,
 			goto out_dh;
 
 		rc = rbd_header_from_disk(header, dh, snap_count, GFP_KERNEL);
-		if (rc < 0)
+		if (rc < 0) {
+			if (rc == -ENXIO) {
+				pr_warning("unrecognized header format"
+					   " for image %s", rbd_dev->obj);
+			}
 			goto out_dh;
+		}
 
 		if (snap_count != header->total_snaps) {
 			snap_count = header->total_snaps;