Messages in this thread Patch in this message | | | From | Bobby Powers <> | Subject | [PATCH v2] Btrfs, lockdep: get_restripe_target: use lockdep in BUG_ON | Date | Wed, 4 Apr 2012 22:04:12 -0400 |
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spin_is_locked always returns 0 on non-SMP systems, which causes btrfs to fail the mount. There is documentation pending as to why checking for spin_is_locked is a bad idea:
https://lkml.org/lkml/2012/3/27/413
The suggested lockdep_assert_held() is not appropriate in this case, as what get_restripe_target() is checking for is that either volume_mutex is held or balance_lock is held. Luckily lockdep_assert_held() is a simple macro:
WARN_ON(debug_locks && !lockdep_is_held(l))
We can mimic the structure in get_restripe_target(), but we need to make sure lockdep_is_held() is defined for the !LOCKDEP case.
CC: Ilya Dryomov <idryomov@gmail.com> CC: Chris Mason <chris.mason@oracle.com> CC: Andi Kleen <ak@linux.intel.com> CC: Jeff Mahoney <jeffm@suse.de> CC: Ingo Molnar <mingo@redhat.com> CC: linux-kernel@vger.kernel.org Signed-off-by: Bobby Powers <bobbypowers@gmail.com> --- fs/btrfs/extent-tree.c | 5 +++-- include/linux/lockdep.h | 1 + 2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index a844204..4d13eb1 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -24,6 +24,7 @@ #include <linux/kthread.h> #include <linux/slab.h> #include <linux/ratelimit.h> +#include <linux/lockdep.h> #include "compat.h" #include "hash.h" #include "ctree.h" @@ -3158,8 +3159,8 @@ static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags) struct btrfs_balance_control *bctl = fs_info->balance_ctl; u64 target = 0; - BUG_ON(!mutex_is_locked(&fs_info->volume_mutex) && - !spin_is_locked(&fs_info->balance_lock)); + BUG_ON(debug_locks && !lockdep_is_held(&fs_info->volume_mutex) && + !lockdep_is_held(&fs_info->balance_lock)); if (!bctl) return 0; diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index d36619e..94c0edb 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -392,6 +392,7 @@ struct lock_class_key { }; #define lockdep_depth(tsk) (0) +#define lockdep_is_held(l) (0) #define lockdep_assert_held(l) do { } while (0) #define lockdep_recursing(tsk) (0) -- 1.7.10.rc3.3.g19a6c
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