[PATCH] locks: add some tracepoints in the lease handling code

From: Jeff Layton
Date: Mon May 05 2014 - 07:58:11 EST


v2: add a __break_lease tracepoint for non-blocking case

Recently, I needed these to help track down a softlockup when recalling a
delegation, but they might be helpful in other situations as well.

Cc: "J. Bruce Fields" <bfields@xxxxxxxxxxxx>
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
---
fs/locks.c | 10 +++++
include/trace/events/filelock.h | 93 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 103 insertions(+)
create mode 100644 include/trace/events/filelock.h

diff --git a/fs/locks.c b/fs/locks.c
index 6b01d5a1de4a..2367f3118662 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -130,6 +130,9 @@
#include <linux/percpu.h>
#include <linux/lglock.h>

+#define CREATE_TRACE_POINTS
+#include <trace/events/filelock.h>
+
#include <asm/uaccess.h>

#define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
@@ -1386,6 +1389,7 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
}

if (i_have_this_lease || (mode & O_NONBLOCK)) {
+ trace_break_lease_noblock(inode, new_fl);
error = -EWOULDBLOCK;
goto out;
}
@@ -1397,10 +1401,12 @@ restart:
if (break_time == 0)
break_time++;
locks_insert_block(flock, new_fl);
+ trace_break_lease_block(inode, new_fl);
spin_unlock(&inode->i_lock);
error = wait_event_interruptible_timeout(new_fl->fl_wait,
!new_fl->fl_next, break_time);
spin_lock(&inode->i_lock);
+ trace_break_lease_unblock(inode, new_fl);
locks_delete_block(new_fl);
if (error >= 0) {
if (error == 0)
@@ -1522,6 +1528,8 @@ static int generic_add_lease(struct file *filp, long arg, struct file_lock **flp
int error;

lease = *flp;
+ trace_generic_add_lease(inode, lease);
+
/*
* In the delegation case we need mutual exclusion with
* a number of operations that take the i_mutex. We trylock
@@ -1611,6 +1619,8 @@ static int generic_delete_lease(struct file *filp, struct file_lock **flp)
struct dentry *dentry = filp->f_path.dentry;
struct inode *inode = dentry->d_inode;

+ trace_generic_delete_lease(inode, *flp);
+
for (before = &inode->i_flock;
((fl = *before) != NULL) && IS_LEASE(fl);
before = &fl->fl_next) {
diff --git a/include/trace/events/filelock.h b/include/trace/events/filelock.h
new file mode 100644
index 000000000000..d1e9d3eaa8ce
--- /dev/null
+++ b/include/trace/events/filelock.h
@@ -0,0 +1,93 @@
+/*
+ * Events for filesystem locks
+ *
+ * Copyright 2013 Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM filelock
+
+#if !defined(_TRACE_FILELOCK_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_FILELOCK_H
+
+#include <linux/tracepoint.h>
+#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/kdev_t.h>
+
+#define show_fl_flags(val) \
+ __print_flags(val, "|", \
+ { FL_POSIX, "FL_POSIX" }, \
+ { FL_FLOCK, "FL_FLOCK" }, \
+ { FL_DELEG, "FL_DELEG" }, \
+ { FL_ACCESS, "FL_ACCESS" }, \
+ { FL_EXISTS, "FL_EXISTS" }, \
+ { FL_LEASE, "FL_LEASE" }, \
+ { FL_CLOSE, "FL_CLOSE" }, \
+ { FL_SLEEP, "FL_SLEEP" }, \
+ { FL_DOWNGRADE_PENDING, "FL_DOWNGRADE_PENDING" }, \
+ { FL_UNLOCK_PENDING, "FL_UNLOCK_PENDING" }, \
+ { FL_OFDLCK, "FL_OFDLCK" })
+
+#define show_fl_type(val) \
+ __print_symbolic(val, \
+ { F_RDLCK, "F_RDLCK" }, \
+ { F_WRLCK, "F_WRLCK" }, \
+ { F_UNLCK, "F_UNLCK" })
+
+DECLARE_EVENT_CLASS(filelock_lease,
+
+ TP_PROTO(struct inode *inode, struct file_lock *fl),
+
+ TP_ARGS(inode, fl),
+
+ 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_flags)
+ __field(unsigned char, fl_type)
+ __field(unsigned long, fl_break_time)
+ __field(unsigned long, fl_downgrade_time)
+ ),
+
+ TP_fast_assign(
+ __entry->fl = fl;
+ __entry->s_dev = inode->i_sb->s_dev;
+ __entry->i_ino = inode->i_ino;
+ __entry->fl_next = fl->fl_next;
+ __entry->fl_owner = fl->fl_owner;
+ __entry->fl_flags = fl->fl_flags;
+ __entry->fl_type = fl->fl_type;
+ __entry->fl_break_time = fl->fl_break_time;
+ __entry->fl_downgrade_time = fl->fl_downgrade_time;
+ ),
+
+ TP_printk("fl=0x%p dev=0x%x:0x%x ino=0x%lx fl_next=0x%p fl_owner=0x%p fl_flags=%s fl_type=%s fl_break_time=%lu fl_downgrade_time=%lu",
+ __entry->fl, MAJOR(__entry->s_dev), MINOR(__entry->s_dev),
+ __entry->i_ino, __entry->fl_next, __entry->fl_owner,
+ show_fl_flags(__entry->fl_flags),
+ show_fl_type(__entry->fl_type),
+ __entry->fl_break_time, __entry->fl_downgrade_time)
+);
+
+DEFINE_EVENT(filelock_lease, break_lease_noblock, TP_PROTO(struct inode *inode, struct file_lock *fl),
+ TP_ARGS(inode, fl));
+
+DEFINE_EVENT(filelock_lease, break_lease_block, TP_PROTO(struct inode *inode, struct file_lock *fl),
+ TP_ARGS(inode, fl));
+
+DEFINE_EVENT(filelock_lease, break_lease_unblock, TP_PROTO(struct inode *inode, struct file_lock *fl),
+ TP_ARGS(inode, fl));
+
+DEFINE_EVENT(filelock_lease, generic_add_lease, TP_PROTO(struct inode *inode, struct file_lock *fl),
+ TP_ARGS(inode, fl));
+
+DEFINE_EVENT(filelock_lease, generic_delete_lease, TP_PROTO(struct inode *inode, struct file_lock *fl),
+ TP_ARGS(inode, fl));
+
+#endif /* _TRACE_FILELOCK_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
--
1.9.0

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