[Ocfs2-devel] [PATCH 11/12] ocfs2_dlm: Dumps the workqueue into a debugfs file

[Sunil Mushran]

This patch dumps all the tasks on the workqueue it can fit in one page
into a debugfs file. Useful for debugging.

Signed-off-by: Sunil Mushran <sunil.mushran at oracle.com>
---
 fs/ocfs2/dlm/dlmdebug.c |   85 +++++++++++++++++++++++++++++++++++++++++++++++
 fs/ocfs2/dlm/dlmdebug.h |    1 +
 2 files changed, 86 insertions(+), 0 deletions(-)

diff --git a/fs/ocfs2/dlm/dlmdebug.c b/fs/ocfs2/dlm/dlmdebug.c
index 25334a4..a05077b 100644
--- a/fs/ocfs2/dlm/dlmdebug.c
+++ b/fs/ocfs2/dlm/dlmdebug.c
@@ -794,6 +794,79 @@ static int debug_buffer_release(struct inode *inode, struct file *file)
 
 /* end - util funcs */
 
+/* begin - work queue funcs */
+static int debug_workqueue_print(struct dlm_ctxt *dlm, struct debug_buffer *db)
+{
+	struct dlm_work_item *wi;
+	int out = 0;
+	unsigned long total = 0;
+
+	spin_lock(&dlm->work_lock);
+
+	list_for_each_entry(wi, &dlm->work_list, list) {
+		++total;
+		if (db->len - out < 100)
+			continue;
+		if (wi->func == dlm_request_all_locks_worker) {
+			out += snprintf(db->buf + out, db->len - out,
+					"RequestAllLocks, "
+					"recomaster=%d, deadnode=%d\n",
+					wi->u.ral.reco_master,
+					wi->u.ral.dead_node);
+		} else if (wi->func == dlm_mig_lockres_worker) {
+			out += snprintf(db->buf + out, db->len - out,
+					"MigrateLockres, %.*s, master=%d\n",
+					wi->u.ml.lockres->lockname.len,
+					wi->u.ml.lockres->lockname.name,
+					wi->u.ml.real_master);
+		} else if (wi->func == dlm_assert_master_worker) {
+			out += snprintf(db->buf + out, db->len - out,
+					"AssertMaster, %.*s, "
+					"from=%d, flags=0x%X, ignore=%d\n",
+					wi->u.am.lockres->lockname.len,
+					wi->u.am.lockres->lockname.name,
+					wi->u.am.request_from,
+					wi->u.am.flags,
+					wi->u.am.ignore_higher);
+		} else {
+			out += snprintf(db->buf + out, db->len - out,
+					"Unknown, 0x%p\n", wi->func);
+		}
+	}
+	spin_unlock(&dlm->work_lock);
+
+	out += snprintf(db->buf + out, db->len - out,
+			"Total on list: %ld\n", total);
+
+	return out;
+}
+
+static int debug_workqueue_open(struct inode *inode, struct file *file)
+{
+	struct dlm_ctxt *dlm = inode->i_private;
+	struct debug_buffer *db;
+
+	db = debug_buffer_allocate();
+	if (!db)
+		goto bail;
+
+	db->len = debug_workqueue_print(dlm, db);
+
+	file->private_data = db;
+
+	return 0;
+bail:
+	return -ENOMEM;
+}
+
+static struct file_operations debug_workqueue_fops = {
+	.open =		debug_workqueue_open,
+	.release =	debug_buffer_release,
+	.read =		debug_buffer_read,
+	.llseek =	debug_buffer_llseek,
+};
+/* end - work queue funcs */
+
 /* begin - purge list funcs */
 static int debug_purgelist_print(struct dlm_ctxt *dlm, struct debug_buffer *db)
 {
@@ -1349,6 +1422,16 @@ int dlm_debug_init(struct dlm_ctxt *dlm)
 		goto bail;
 	}
 
+	/* for dumping the dlm work queue */
+	dc->debug_workqueue_dentry =
+			debugfs_create_file("workqueue", S_IFREG|S_IRUSR,
+					    dlm->dlm_debugfs_subroot,
+					    dlm, &debug_workqueue_fops);
+	if (!dc->debug_workqueue_dentry) {
+		mlog_errno(-ENOMEM);
+		goto bail;
+	}
+
 	dlm_debug_get(dc);
 	return 0;
 
@@ -1362,6 +1445,8 @@ void dlm_debug_shutdown(struct dlm_ctxt *dlm)
 	struct dlm_debug_ctxt *dc = dlm->dlm_debug_ctxt;
 
 	if (dc) {
+		if (dc->debug_workqueue_dentry)
+			debugfs_remove(dc->debug_workqueue_dentry);
 		if (dc->debug_purgelist_dentry)
 			debugfs_remove(dc->debug_purgelist_dentry);
 		if (dc->debug_mle_dentry)
diff --git a/fs/ocfs2/dlm/dlmdebug.h b/fs/ocfs2/dlm/dlmdebug.h
index ca7bc32..fcc19c8 100644
--- a/fs/ocfs2/dlm/dlmdebug.h
+++ b/fs/ocfs2/dlm/dlmdebug.h
@@ -31,6 +31,7 @@ struct dlm_debug_ctxt {
 	struct dentry *debug_lockres_dentry;
 	struct dentry *debug_mle_dentry;
 	struct dentry *debug_purgelist_dentry;
+	struct dentry *debug_workqueue_dentry;
 };
 
 struct debug_buffer
-- 
1.5.2.5