From: David Sterba <dsterba@suse.cz>
Date: Thu, 26 Jan 2012 20:01:12 +0000 (-0500)
Subject: btrfs: fix structs where bitfields and spinlock/atomic share 8B word
X-Git-Tag: MMI-PSA29.97-13-9~17312^2~17
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=c08782dacd7a098f2b8bca7f4a57a5b402e9e1e5;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git

btrfs: fix structs where bitfields and spinlock/atomic share 8B word

On ia64, powerpc64 and sparc64 the bitfield is modified through a RMW cycle and current
gcc rewrites the adjacent 4B word, which in case of a spinlock or atomic has
disaterous effect.

https://lkml.org/lkml/2012/2/1/220

Signed-off-by: David Sterba <dsterba@suse.cz>
---

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 3c2cbf7b6663..8e4457e0478e 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -886,7 +886,7 @@ struct btrfs_block_rsv {
 	u64 reserved;
 	struct btrfs_space_info *space_info;
 	spinlock_t lock;
-	unsigned int full:1;
+	unsigned int full;
 };
 
 /*
diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
index 33a7890b1f40..1195f09761fe 100644
--- a/fs/btrfs/extent_map.h
+++ b/fs/btrfs/extent_map.h
@@ -26,8 +26,8 @@ struct extent_map {
 	unsigned long flags;
 	struct block_device *bdev;
 	atomic_t refs;
-	unsigned int in_tree:1;
-	unsigned int compress_type:4;
+	unsigned int in_tree;
+	unsigned int compress_type;
 };
 
 struct extent_map_tree {