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: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
---
fs/gfs2/file.c | 22 ++++++++++++++++++++--
fs/gfs2/glock.c | 23 +++++++++++++++++++++++
2 files changed, 43 insertions(+), 2 deletions(-)
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 2cceb193dcd8..25f4080bc973 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -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);
}
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 63dbab6fa242..aa35f5d4eb54 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -2844,6 +2844,28 @@ 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;
@@ -2857,6 +2879,7 @@ 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;
}
--
2.35.1
