locks: add some tracepoints in the lease handling code

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@fieldses.org>
Signed-off-by: Jeff Layton <jlayton@poochiereds.net>

1 files changed, 11 insertions, 0 deletions

diff --git a/fs/locks.c b/fs/locks.c
index facf76d9fcb4..da57c9b7e844 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)
@@ -1287,6 +1290,7 @@ static void time_out_leases(struct inode *inode)
 
         before = &inode->i_flock;
         while ((fl = *before) && IS_LEASE(fl) && lease_breaking(fl)) {
+                trace_time_out_leases(inode, fl);
                 if (past_time(fl->fl_downgrade_time))
                         lease_modify(before, F_RDLCK);
                 if (past_time(fl->fl_break_time))
@@ -1374,6 +1378,7 @@ 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;
         }
@@ -1385,10 +1390,12 @@ 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)
@@ -1510,6 +1517,8 @@ 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
@@ -1599,6 +1608,8 @@ 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) {