Commit 56535dc6 authored by Andreas Gruenbacher's avatar Andreas Gruenbacher
Browse files

gfs2: Add flocks to glockfd debugfs file 



Include flock glocks in the "glockfd" debugfs file.  Those are similar to the
iopen glocks; while an open file is holding an flock, it is holding the file's
flock glock.

We cannot take f_fl_mutex in gfs2_glockfd_seq_show_flock() or else dumping the
"glockfd" file would block on flock operations.  Instead, use the file->f_lock
spin lock to protect the f_fl_gh.gh_gl glock pointer.

Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
parent 4480c27c

fs/gfs2/file.c

+20 −2
Original line number Diff line number Diff line
@@ -1444,6 +1444,22 @@ static int gfs2_lock(struct file *file, int cmd, struct file_lock *fl) 
		return dlm_posix_lock(ls->ls_dlm, ip->i_no_addr, file, cmd, fl);

}



static void __flock_holder_uninit(struct file *file, struct gfs2_holder *fl_gh)

{

	struct gfs2_glock *gl = fl_gh->gh_gl;



	/*

	 * Make sure gfs2_glock_put() won't sleep under the file->f_lock

	 * spinlock.

	 */



	gfs2_glock_hold(gl);

	spin_lock(&file->f_lock);

	gfs2_holder_uninit(fl_gh);

	spin_unlock(&file->f_lock);

	gfs2_glock_put(gl);

}



static int do_flock(struct file *file, int cmd, struct file_lock *fl)

{

	struct gfs2_file *fp = file->private_data;
@@ -1475,7 +1491,9 @@ static int do_flock(struct file *file, int cmd, struct file_lock *fl) 
				       &gfs2_flock_glops, CREATE, &gl);

		if (error)

			goto out;

		spin_lock(&file->f_lock);

		gfs2_holder_init(gl, state, flags, fl_gh);

		spin_unlock(&file->f_lock);

		gfs2_glock_put(gl);

	}

	for (sleeptime = 1; sleeptime <= 4; sleeptime <<= 1) {
@@ -1486,7 +1504,7 @@ static int do_flock(struct file *file, int cmd, struct file_lock *fl) 
		msleep(sleeptime);

	}

	if (error) {

		gfs2_holder_uninit(fl_gh);

		__flock_holder_uninit(file, fl_gh);

		if (error == GLR_TRYFAILED)

			error = -EAGAIN;

	} else {
@@ -1508,7 +1526,7 @@ static void do_unflock(struct file *file, struct file_lock *fl) 
	locks_lock_file_wait(file, fl);

	if (gfs2_holder_initialized(fl_gh)) {

		gfs2_glock_dq(fl_gh);

		gfs2_holder_uninit(fl_gh);

		__flock_holder_uninit(file, fl_gh);

	}

	mutex_unlock(&fp->f_fl_mutex);

}

fs/gfs2/glock.c

+23 −0
Original line number Diff line number Diff line
@@ -2846,6 +2846,28 @@ static void gfs2_glockfd_seq_stop(struct seq_file *seq, void *iter_ptr) 
		put_task_struct(i->task);

}



static void gfs2_glockfd_seq_show_flock(struct seq_file *seq,

					struct gfs2_glockfd_iter *i)

{

	struct gfs2_file *fp = i->file->private_data;

	struct gfs2_holder *fl_gh = &fp->f_fl_gh;

	struct lm_lockname gl_name = { .ln_type = LM_TYPE_RESERVED };



	if (!READ_ONCE(fl_gh->gh_gl))

		return;



	spin_lock(&i->file->f_lock);

	if (gfs2_holder_initialized(fl_gh))

		gl_name = fl_gh->gh_gl->gl_name;

	spin_unlock(&i->file->f_lock);



	if (gl_name.ln_type != LM_TYPE_RESERVED) {

		seq_printf(seq, "%d %u %u/%llx\n",

			   i->tgid, i->fd, gl_name.ln_type,

			   (unsigned long long)gl_name.ln_number);

	}

}



static int gfs2_glockfd_seq_show(struct seq_file *seq, void *iter_ptr)

{

	struct gfs2_glockfd_iter *i = seq->private;
@@ -2859,6 +2881,7 @@ static int gfs2_glockfd_seq_show(struct seq_file *seq, void *iter_ptr) 
			   i->tgid, i->fd, gl->gl_name.ln_type,

			   (unsigned long long)gl->gl_name.ln_number);

	}

	gfs2_glockfd_seq_show_flock(seq, i);

	inode_unlock_shared(inode);

	return 0;

}