[PATCH v2 3/6] locks: sprinkle some tracepoints around the file locking code

[Jeff Layton <jlayton@poochiereds.net>]

Add some tracepoints around the POSIX locking code. These were useful
when tracking down problems when handling the race between setlk and
close.

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
---
 fs/locks.c                      | 12 +++++--
 include/trace/events/filelock.h | 77 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 86 insertions(+), 3 deletions(-)

diff --git a/fs/locks.c b/fs/locks.c
index e72077d5a664..0af2387bd91e 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -229,6 +229,7 @@ locks_get_lock_context(struct inode *inode, int type)
 		ctx = smp_load_acquire(&inode->i_flctx);
 	}
 out:
+	trace_locks_get_lock_context(inode, type, ctx);
 	return ctx;
 }
 
@@ -1141,6 +1142,8 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
 	if (new_fl2)
 		locks_free_lock(new_fl2);
 	locks_dispose_list(&dispose);
+	trace_posix_lock_inode(inode, request, error);
+
 	return error;
 }
 
@@ -2164,6 +2167,8 @@ int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
 	if (file_lock == NULL)
 		return -ENOLCK;
 
+	inode = file_inode(filp);
+
 	/*
 	 * This might block, so we do it before checking the inode.
 	 */
@@ -2171,8 +2176,6 @@ int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
 	if (copy_from_user(&flock, l, sizeof(flock)))
 		goto out;
 
-	inode = file_inode(filp);
-
 	/* Don't allow mandatory locks on files that may be memory mapped
 	 * and shared.
 	 */
@@ -2241,6 +2244,7 @@ int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
 		}
 	}
 out:
+	trace_fcntl_setlk(inode, file_lock, error);
 	locks_free_lock(file_lock);
 	return error;
 }
@@ -2397,6 +2401,7 @@ out:
  */
 void locks_remove_posix(struct file *filp, fl_owner_t owner)
 {
+	int error;
 	struct file_lock lock;
 	struct file_lock_context *ctx;
 
@@ -2419,10 +2424,11 @@ void locks_remove_posix(struct file *filp, fl_owner_t owner)
 	lock.fl_ops = NULL;
 	lock.fl_lmops = NULL;
 
-	vfs_lock_file(filp, F_SETLK, &lock, NULL);
+	error = vfs_lock_file(filp, F_SETLK, &lock, NULL);
 
 	if (lock.fl_ops && lock.fl_ops->fl_release_private)
 		lock.fl_ops->fl_release_private(&lock);
+	trace_locks_remove_posix(file_inode(filp), &lock, error);
 }
 
 EXPORT_SYMBOL(locks_remove_posix);
diff --git a/include/trace/events/filelock.h b/include/trace/events/filelock.h
index c72f2dc01d0b..63a7680347cb 100644
--- a/include/trace/events/filelock.h
+++ b/include/trace/events/filelock.h
@@ -34,6 +34,83 @@
 			{ F_WRLCK, "F_WRLCK" },		\
 			{ F_UNLCK, "F_UNLCK" })
 
+TRACE_EVENT(locks_get_lock_context,
+	TP_PROTO(struct inode *inode, int type, struct file_lock_context *ctx),
+
+	TP_ARGS(inode, type, ctx),
+
+	TP_STRUCT__entry(
+		__field(unsigned long, i_ino)
+		__field(dev_t, s_dev)
+		__field(unsigned char, type)
+		__field(struct file_lock_context *, ctx)
+	),
+
+	TP_fast_assign(
+		__entry->s_dev = inode->i_sb->s_dev;
+		__entry->i_ino = inode->i_ino;
+		__entry->type = type;
+		__entry->ctx = ctx;
+	),
+
+	TP_printk("dev=0x%x:0x%x ino=0x%lx type=%s ctx=%p",
+		  MAJOR(__entry->s_dev), MINOR(__entry->s_dev),
+		  __entry->i_ino, show_fl_type(__entry->type), __entry->ctx)
+);
+
+DECLARE_EVENT_CLASS(filelock_lock,
+	TP_PROTO(struct inode *inode, struct file_lock *fl, int ret),
+
+	TP_ARGS(inode, fl, ret),
+
+	TP_STRUCT__entry(
+		__field(struct file_lock *, fl)
+		__field(unsigned long, i_ino)
+		__field(dev_t, s_dev)
+		__field(struct file_lock *, fl_next)
+		__field(fl_owner_t, fl_owner)
+		__field(unsigned int, fl_pid)
+		__field(unsigned int, fl_flags)
+		__field(unsigned char, fl_type)
+		__field(loff_t, fl_start)
+		__field(loff_t, fl_end)
+		__field(int, ret)
+	),
+
+	TP_fast_assign(
+		__entry->fl = fl ? fl : NULL;
+		__entry->s_dev = inode->i_sb->s_dev;
+		__entry->i_ino = inode->i_ino;
+		__entry->fl_next = fl ? fl->fl_next : NULL;
+		__entry->fl_owner = fl ? fl->fl_owner : NULL;
+		__entry->fl_pid = fl ? fl->fl_pid : 0;
+		__entry->fl_flags = fl ? fl->fl_flags : 0;
+		__entry->fl_type = fl ? fl->fl_type : 0;
+		__entry->fl_start = fl ? fl->fl_start : 0;
+		__entry->fl_end = fl ? fl->fl_end : 0;
+		__entry->ret = ret;
+	),
+
+	TP_printk("fl=0x%p dev=0x%x:0x%x ino=0x%lx fl_next=0x%p fl_owner=0x%p fl_pid=%u fl_flags=%s fl_type=%s fl_start=%lld fl_end=%lld ret=%d",
+		__entry->fl, MAJOR(__entry->s_dev), MINOR(__entry->s_dev),
+		__entry->i_ino, __entry->fl_next, __entry->fl_owner,
+		__entry->fl_pid, show_fl_flags(__entry->fl_flags),
+		show_fl_type(__entry->fl_type),
+		__entry->fl_start, __entry->fl_end, __entry->ret)
+);
+
+DEFINE_EVENT(filelock_lock, posix_lock_inode,
+		TP_PROTO(struct inode *inode, struct file_lock *fl, int ret),
+		TP_ARGS(inode, fl, ret));
+
+DEFINE_EVENT(filelock_lock, fcntl_setlk,
+		TP_PROTO(struct inode *inode, struct file_lock *fl, int ret),
+		TP_ARGS(inode, fl, ret));
+
+DEFINE_EVENT(filelock_lock, locks_remove_posix,
+		TP_PROTO(struct inode *inode, struct file_lock *fl, int ret),
+		TP_ARGS(inode, fl, ret));
+
 DECLARE_EVENT_CLASS(filelock_lease,
 
 	TP_PROTO(struct inode *inode, struct file_lock *fl),
-- 
2.5.0