Re: [PATCH RFC 01/10] fs/locks: Add trace_leases_conflict

Jeff Layton
2019-06-09T12:52:27Z

On Wed, 2019-06-05 at 18:45 -0700, ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com>
>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> ---
> fs/locks.c | 20 ++++++++++++++-----
> include/trace/events/filelock.h | 35 +++++++++++++++++++++++++++++++++
> 2 files changed, 50 insertions(+), 5 deletions(-)
>
> diff --git a/fs/locks.c b/fs/locks.c
> index ec1e4a5df629..0cc2b9f30e22 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -1534,11 +1534,21 @@ static void time_out_leases(struct inode *inode, struct list_head *dispose)
>
> static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
> {
> - if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT))
> - return false;
> - if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE))
> - return false;
> - return locks_conflict(breaker, lease);
> + bool rc;
> +
> + if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT)) {
> + rc = false;
> + goto trace;
> + }
> + if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE)) {
> + rc = false;
> + goto trace;
> + }
> +
> + rc = locks_conflict(breaker, lease);
> +trace:
> + trace_leases_conflict(rc, lease, breaker);
> + return rc;
> }
>
> static bool
> diff --git a/include/trace/events/filelock.h b/include/trace/events/filelock.h
> index fad7befa612d..4b735923f2ff 100644
> --- a/include/trace/events/filelock.h
> +++ b/include/trace/events/filelock.h
> @@ -203,6 +203,41 @@ TRACE_EVENT(generic_add_lease,
> show_fl_type(__entry->fl_type))
> );
>
> +TRACE_EVENT(leases_conflict,
> + TP_PROTO(bool conflict, struct file_lock *lease, struct file_lock *breaker),
> +
> + TP_ARGS(conflict, lease, breaker),
> +
> + TP_STRUCT__entry(
> + __field(void *, lease)
> + __field(void *, breaker)
> + __field(unsigned int, l_fl_flags)
> + __field(unsigned int, b_fl_flags)
> + __field(unsigned char, l_fl_type)
> + __field(unsigned char, b_fl_type)
> + __field(bool, conflict)
> + ),
> +
> + TP_fast_assign(
> + __entry->lease = lease;
> + __entry->l_fl_flags = lease->fl_flags;
> + __entry->l_fl_type = lease->fl_type;
> + __entry->breaker = breaker;
> + __entry->b_fl_flags = breaker->fl_flags;
> + __entry->b_fl_type = breaker->fl_type;
> + __entry->conflict = conflict;
> + ),
> +
> + TP_printk("conflict %d: lease=0x%p fl_flags=%s fl_type=%s; breaker=0x%p fl_flags=%s fl_type=%s",
> + __entry->conflict,
> + __entry->lease,
> + show_fl_flags(__entry->l_fl_flags),
> + show_fl_type(__entry->l_fl_type),
> + __entry->breaker,
> + show_fl_flags(__entry->b_fl_flags),
> + show_fl_type(__entry->b_fl_type))
> +);
> +
> #endif /* _TRACE_FILELOCK_H */
>
> /* This part must be outside protection */

This looks useful. I'll plan to merge this one for v5.3 unless there
are objections.

Reviewed-by: Jeff Layton <jlayton@kernel.org>