ocfs2/dlm: Dump the dlm state in a debugfs file

This patch dumps the dlm state (dlm_ctxt) into a debugfs file.
Useful for debugging.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

1 files changed, 296 insertions, 0 deletions

diff --git a/fs/ocfs2/dlm/dlmdebug.c b/fs/ocfs2/dlm/dlmdebug.c
index 62e2a4cbf60d..e33540380013 100644
--- a/fs/ocfs2/dlm/dlmdebug.c
+++ b/fs/ocfs2/dlm/dlmdebug.c
@@ -274,6 +274,294 @@ EXPORT_SYMBOL_GPL(dlm_errname);
 static struct dentry *dlm_debugfs_root = NULL;
 
 #define DLM_DEBUGFS_DIR                         "o2dlm"
+#define DLM_DEBUGFS_DLM_STATE                   "dlm_state"
+
+/* begin - utils funcs */
+static void dlm_debug_free(struct kref *kref)
+{
+        struct dlm_debug_ctxt *dc;
+
+        dc = container_of(kref, struct dlm_debug_ctxt, debug_refcnt);
+
+        kfree(dc);
+}
+
+void dlm_debug_put(struct dlm_debug_ctxt *dc)
+{
+        if (dc)
+                kref_put(&dc->debug_refcnt, dlm_debug_free);
+}
+
+static void dlm_debug_get(struct dlm_debug_ctxt *dc)
+{
+        kref_get(&dc->debug_refcnt);
+}
+
+static int stringify_nodemap(unsigned long *nodemap, int maxnodes,
+                             char *buf, int len)
+{
+        int out = 0;
+        int i = -1;
+
+        while ((i = find_next_bit(nodemap, maxnodes, i + 1)) < maxnodes)
+                out += snprintf(buf + out, len - out, "%d ", i);
+
+        return out;
+}
+
+static struct debug_buffer *debug_buffer_allocate(void)
+{
+        struct debug_buffer *db = NULL;
+
+        db = kzalloc(sizeof(struct debug_buffer), GFP_KERNEL);
+        if (!db)
+                goto bail;
+
+        db->len = PAGE_SIZE;
+        db->buf = kmalloc(db->len, GFP_KERNEL);
+        if (!db->buf)
+                goto bail;
+
+        return db;
+bail:
+        kfree(db);
+        return NULL;
+}
+
+static ssize_t debug_buffer_read(struct file *file, char __user *buf,
+                                 size_t nbytes, loff_t *ppos)
+{
+        struct debug_buffer *db = file->private_data;
+
+        return simple_read_from_buffer(buf, nbytes, ppos, db->buf, db->len);
+}
+
+static loff_t debug_buffer_llseek(struct file *file, loff_t off, int whence)
+{
+        struct debug_buffer *db = file->private_data;
+        loff_t new = -1;
+
+        switch (whence) {
+        case 0:
+                new = off;
+                break;
+        case 1:
+                new = file->f_pos + off;
+                break;
+        }
+
+        if (new < 0 || new > db->len)
+                return -EINVAL;
+
+        return (file->f_pos = new);
+}
+
+static int debug_buffer_release(struct inode *inode, struct file *file)
+{
+        struct debug_buffer *db = (struct debug_buffer *)file->private_data;
+
+        if (db)
+                kfree(db->buf);
+        kfree(db);
+
+        return 0;
+}
+/* end - util funcs */
+
+/* begin - debug state funcs */
+static int debug_state_print(struct dlm_ctxt *dlm, struct debug_buffer *db)
+{
+        int out = 0;
+        struct dlm_reco_node_data *node;
+        char *state;
+        int lres, rres, ures, tres;
+
+        lres = atomic_read(&dlm->local_resources);
+        rres = atomic_read(&dlm->remote_resources);
+        ures = atomic_read(&dlm->unknown_resources);
+        tres = lres + rres + ures;
+
+        spin_lock(&dlm->spinlock);
+
+        switch (dlm->dlm_state) {
+        case DLM_CTXT_NEW:
+                state = "NEW"; break;
+        case DLM_CTXT_JOINED:
+                state = "JOINED"; break;
+        case DLM_CTXT_IN_SHUTDOWN:
+                state = "SHUTDOWN"; break;
+        case DLM_CTXT_LEAVING:
+                state = "LEAVING"; break;
+        default:
+                state = "UNKNOWN"; break;
+        }
+
+        /* Domain: xxxxxxxxxx  Key: 0xdfbac769 */
+        out += snprintf(db->buf + out, db->len - out,
+                        "Domain: %s  Key: 0x%08x\n", dlm->name, dlm->key);
+
+        /* Thread Pid: xxx  Node: xxx  State: xxxxx */
+        out += snprintf(db->buf + out, db->len - out,
+                        "Thread Pid: %d  Node: %d  State: %s\n",
+                        dlm->dlm_thread_task->pid, dlm->node_num, state);
+
+        /* Number of Joins: xxx  Joining Node: xxx */
+        out += snprintf(db->buf + out, db->len - out,
+                        "Number of Joins: %d  Joining Node: %d\n",
+                        dlm->num_joins, dlm->joining_node);
+
+        /* Domain Map: xx xx xx */
+        out += snprintf(db->buf + out, db->len - out, "Domain Map: ");
+        out += stringify_nodemap(dlm->domain_map, O2NM_MAX_NODES,
+                                 db->buf + out, db->len - out);
+        out += snprintf(db->buf + out, db->len - out, "\n");
+
+        /* Live Map: xx xx xx */
+        out += snprintf(db->buf + out, db->len - out, "Live Map: ");
+        out += stringify_nodemap(dlm->live_nodes_map, O2NM_MAX_NODES,
+                                 db->buf + out, db->len - out);
+        out += snprintf(db->buf + out, db->len - out, "\n");
+
+        /* Mastered Resources Total: xxx  Locally: xxx  Remotely: ... */
+        out += snprintf(db->buf + out, db->len - out,
+                        "Mastered Resources Total: %d  Locally: %d  "
+                        "Remotely: %d  Unknown: %d\n",
+                        tres, lres, rres, ures);
+
+        /* Lists: Dirty=Empty  Purge=InUse  PendingASTs=Empty  ... */
+        out += snprintf(db->buf + out, db->len - out,
+                        "Lists: Dirty=%s  Purge=%s  PendingASTs=%s  "
+                        "PendingBASTs=%s  Master=%s\n",
+                        (list_empty(&dlm->dirty_list) ? "Empty" : "InUse"),
+                        (list_empty(&dlm->purge_list) ? "Empty" : "InUse"),
+                        (list_empty(&dlm->pending_asts) ? "Empty" : "InUse"),
+                        (list_empty(&dlm->pending_basts) ? "Empty" : "InUse"),
+                        (list_empty(&dlm->master_list) ? "Empty" : "InUse"));
+
+        /* Purge Count: xxx  Refs: xxx */
+        out += snprintf(db->buf + out, db->len - out,
+                        "Purge Count: %d  Refs: %d\n", dlm->purge_count,
+                        atomic_read(&dlm->dlm_refs.refcount));
+
+        /* Dead Node: xxx */
+        out += snprintf(db->buf + out, db->len - out,
+                        "Dead Node: %d\n", dlm->reco.dead_node);
+
+        /* What about DLM_RECO_STATE_FINALIZE? */
+        if (dlm->reco.state == DLM_RECO_STATE_ACTIVE)
+                state = "ACTIVE";
+        else
+                state = "INACTIVE";
+
+        /* Recovery Pid: xxxx  Master: xxx  State: xxxx */
+        out += snprintf(db->buf + out, db->len - out,
+                        "Recovery Pid: %d  Master: %d  State: %s\n",
+                        dlm->dlm_reco_thread_task->pid,
+                        dlm->reco.new_master, state);
+
+        /* Recovery Map: xx xx */
+        out += snprintf(db->buf + out, db->len - out, "Recovery Map: ");
+        out += stringify_nodemap(dlm->recovery_map, O2NM_MAX_NODES,
+                                 db->buf + out, db->len - out);
+        out += snprintf(db->buf + out, db->len - out, "\n");
+
+        /* Recovery Node State: */
+        out += snprintf(db->buf + out, db->len - out, "Recovery Node State:\n");
+        list_for_each_entry(node, &dlm->reco.node_data, list) {
+                switch (node->state) {
+                case DLM_RECO_NODE_DATA_INIT:
+                        state = "INIT";
+                        break;
+                case DLM_RECO_NODE_DATA_REQUESTING:
+                        state = "REQUESTING";
+                        break;
+                case DLM_RECO_NODE_DATA_DEAD:
+                        state = "DEAD";
+                        break;
+                case DLM_RECO_NODE_DATA_RECEIVING:
+                        state = "RECEIVING";
+                        break;
+                case DLM_RECO_NODE_DATA_REQUESTED:
+                        state = "REQUESTED";
+                        break;
+                case DLM_RECO_NODE_DATA_DONE:
+                        state = "DONE";
+                        break;
+                case DLM_RECO_NODE_DATA_FINALIZE_SENT:
+                        state = "FINALIZE-SENT";
+                        break;
+                default:
+                        state = "BAD";
+                        break;
+                }
+                out += snprintf(db->buf + out, db->len - out, "\t%u - %s\n",
+                                node->node_num, state);
+        }
+
+        spin_unlock(&dlm->spinlock);
+
+        return out;
+}
+
+static int debug_state_open(struct inode *inode, struct file *file)
+{
+        struct dlm_ctxt *dlm = inode->i_private;
+        struct debug_buffer *db = NULL;
+
+        db = debug_buffer_allocate();
+        if (!db)
+                goto bail;
+
+        db->len = debug_state_print(dlm, db);
+
+        file->private_data = db;
+
+        return 0;
+bail:
+        return -ENOMEM;
+}
+
+static struct file_operations debug_state_fops = {
+        .open =         debug_state_open,
+        .release =      debug_buffer_release,
+        .read =         debug_buffer_read,
+        .llseek =       debug_buffer_llseek,
+};
+/* end  - debug state funcs */
+
+/* files in subroot */
+int dlm_debug_init(struct dlm_ctxt *dlm)
+{
+        struct dlm_debug_ctxt *dc = dlm->dlm_debug_ctxt;
+
+        /* for dumping dlm_ctxt */
+        dc->debug_state_dentry = debugfs_create_file(DLM_DEBUGFS_DLM_STATE,
+                                                     S_IFREG|S_IRUSR,
+                                                     dlm->dlm_debugfs_subroot,
+                                                     dlm, &debug_state_fops);
+        if (!dc->debug_state_dentry) {
+                mlog_errno(-ENOMEM);
+                goto bail;
+        }
+
+        dlm_debug_get(dc);
+        return 0;
+
+bail:
+        dlm_debug_shutdown(dlm);
+        return -ENOMEM;
+}
+
+void dlm_debug_shutdown(struct dlm_ctxt *dlm)
+{
+        struct dlm_debug_ctxt *dc = dlm->dlm_debug_ctxt;
+
+        if (dc) {
+                if (dc->debug_state_dentry)
+                        debugfs_remove(dc->debug_state_dentry);
+                dlm_debug_put(dc);
+        }
+}
 
 /* subroot - domain dir */
 int dlm_create_debugfs_subroot(struct dlm_ctxt *dlm)
@@ -285,6 +573,14 @@ int dlm_create_debugfs_subroot(struct dlm_ctxt *dlm)
                 goto bail;
         }
 
+        dlm->dlm_debug_ctxt = kzalloc(sizeof(struct dlm_debug_ctxt),
+                                      GFP_KERNEL);
+        if (!dlm->dlm_debug_ctxt) {
+                mlog_errno(-ENOMEM);
+                goto bail;
+        }
+        kref_init(&dlm->dlm_debug_ctxt->debug_refcnt);
+
         return 0;
 bail:
         dlm_destroy_debugfs_subroot(dlm);