Hi Josef,

FYI, kernel build failed on

tree:   git://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-next.git extent-history
head:   7759db1867be3d642b2411455902ed22dd6d1381
commit: 7759db1867be3d642b2411455902ed22dd6d1381 [20/20] Btrfs: extent history debugging patch
config: i386-randconfig-k662 (attached as .config)

All related error/warning messages:

In file included from fs/btrfs/transaction.h:22:0,
                 from fs/btrfs/ioctl.c:48:
fs/btrfs/delayed-ref.h:125:21: error: field 'trace' has incomplete type
--
In file included from fs/btrfs/transaction.h:22:0,
                 from fs/btrfs/tree-log.c:22:
fs/btrfs/delayed-ref.h:125:21: error: field 'trace' has incomplete type
--
In file included from fs/btrfs/transaction.h:22:0,
                 from fs/btrfs/free-space-cache.c:26:
fs/btrfs/delayed-ref.h:125:21: error: field 'trace' has incomplete type
--
In file included from fs/btrfs/transaction.h:22:0,
                 from fs/btrfs/compression.c:38:
fs/btrfs/delayed-ref.h:125:21: error: field 'trace' has incomplete type
--
In file included from fs/btrfs/delayed-ref.c:23:0:
fs/btrfs/delayed-ref.h:125:21: error: field 'trace' has incomplete type
--
In file included from fs/btrfs/transaction.h:22:0,
                 from fs/btrfs/relocation.c:27:
fs/btrfs/delayed-ref.h:125:21: error: field 'trace' has incomplete type
--
In file included from fs/btrfs/transaction.h:22:0,
                 from fs/btrfs/delayed-inode.c:23:
fs/btrfs/delayed-ref.h:125:21: error: field 'trace' has incomplete type
--
In file included from fs/btrfs/transaction.h:22:0,
                 from fs/btrfs/scrub.c:25:
fs/btrfs/delayed-ref.h:125:21: error: field 'trace' has incomplete type
--
In file included from fs/btrfs/transaction.h:22:0,
                 from fs/btrfs/reada.c:29:
fs/btrfs/delayed-ref.h:125:21: error: field 'trace' has incomplete type
--
In file included from fs/btrfs/transaction.h:22:0,
                 from fs/btrfs/backref.c:23:
fs/btrfs/delayed-ref.h:125:21: error: field 'trace' has incomplete type
--
In file included from fs/btrfs/transaction.h:22:0,
                 from fs/btrfs/super.c:48:
fs/btrfs/delayed-ref.h:125:21: error: field 'trace' has incomplete type
..

vim +125 fs/btrfs/delayed-ref.h
   122		u64 ref_root;
   123		u64 owner;
   124		int action;
 > 125		struct stack_trace trace;
   126		unsigned long entries[32];
   127		struct list_head list;
   128		struct rb_node node;

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0-DAY kernel build testing backend         Open Source Technology Centre
Fengguang Wu [off-list ref]                     Intel Corporation