Patch "dm cache: the CLEAN_SHUTDOWN flag was not being set" has been added to the 4.2-stable tree

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

dm cache: the CLEAN_SHUTDOWN flag was not being set

to the 4.2-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-cache-the-clean_shutdown-flag-was-not-being-set.patch
and it can be found in the queue-4.2 subdirectory.

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

From: Joe Thornber <[email protected]>
Date: Thu, 22 Oct 2015 18:10:55 +0100
Subject: dm cache: the CLEAN_SHUTDOWN flag was not being set

From: Joe Thornber <[email protected]>

commit 3201ac452e84a8a368197d648c9b7011e061804a upstream.

If the CLEAN_SHUTDOWN flag is not set when a cache is loaded then all cache blocks are marked as dirty and a full writeback occurs.

__commit_transaction() is responsible for setting/clearing CLEAN_SHUTDOWN (based the flags_mutator that is passed in).

Fix this issue, of the cache's on-disk flags being wrong, by making sure __commit_transaction() does not reset the flags after the mutator has altered the flags in preparation for them being serialized to disk.

before:

sb_flags = mutator(le32_to_cpu(disk_super->flags)); disk_super->flags = cpu_to_le32(sb_flags); disk_super->flags = cpu_to_le32(cmd->flags);

after:

disk_super->flags = cpu_to_le32(cmd->flags); sb_flags = mutator(le32_to_cpu(disk_super->flags)); disk_super->flags = cpu_to_le32(sb_flags);

---
 drivers/md/dm-cache-metadata.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -634,10 +634,10 @@ static int __commit_transaction(struct d
 
 	disk_super = dm_block_data(sblock);
 
+	disk_super->flags = cpu_to_le32(cmd->flags);
 	if (mutator)
 		update_flags(disk_super, mutator);
 
-	disk_super->flags = cpu_to_le32(cmd->flags);
 	disk_super->mapping_root = cpu_to_le64(cmd->root);
 	disk_super->hint_root = cpu_to_le64(cmd->hint_root);
 	disk_super->discard_root = cpu_to_le64(cmd->discard_root);

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

queue-4.2/dm-btree-remove-fix-a-bug-when-rebalancing-nodes-after-removal.patch queue-4.2/dm-cache-the-clean_shutdown-flag-was-not-being-set.patch