Patch "dm era: save spacemap metadata root after the pre-commit" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

dm era: save spacemap metadata root after the pre-commit

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
dm-era-save-spacemap-metadata-root-after-the-pre-commit.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Somasundaram Krishnasamy <[email protected]>
Date: Fri, 7 Apr 2017 12:14:55 -0700
Subject: dm era: save spacemap metadata root after the pre-commit

From: Somasundaram Krishnasamy <[email protected]>

commit 117aceb030307dcd431fdcff87ce988d3016c34a upstream.

When committing era metadata to disk, it doesn't always save the latest spacemap metadata root in superblock. Due to this, metadata is getting corrupted sometimes when reopening the device. The correct order of update should be, pre-commit (shadows spacemap root), save the spacemap root (newly shadowed block) to in-core superblock and then the final commit.

---
 drivers/md/dm-era-target.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

@@ -961,15 +961,15 @@ static int metadata_commit(struct era_me
 		}
 	}
 
-	r = save_sm_root(md);
+	r = dm_tm_pre_commit(md->tm);
 	if (r) {
-		DMERR("%s: save_sm_root failed", __func__);
+		DMERR("%s: pre commit failed", __func__);
 		return r;
 	}
 
-	r = dm_tm_pre_commit(md->tm);
+	r = save_sm_root(md);
 	if (r) {
-		DMERR("%s: pre commit failed", __func__);
+		DMERR("%s: save_sm_root failed", __func__);
 		return r;
 	}
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/dm-era-save-spacemap-metadata-root-after-the-pre-commit.patch