ocfs2/dlm: Dumps the lockres' into a debugfs file

This patch dumps all the lockres' alongwith all the locks 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>

2 files changed, 255 insertions, 0 deletions

diff --git a/fs/ocfs2/dlm/dlmdebug.c b/fs/ocfs2/dlm/dlmdebug.c
index e33540380013..cccb1ce33723 100644
--- a/fs/ocfs2/dlm/dlmdebug.c
+++ b/fs/ocfs2/dlm/dlmdebug.c
@@ -273,8 +273,35 @@ EXPORT_SYMBOL_GPL(dlm_errname);
 
 static struct dentry *dlm_debugfs_root = NULL;
 
+/* NOTE: This function converts a lockname into a string. It uses knowledge
+ * of the format of the lockname that should be outside the purview of the dlm.
+ * We are adding only to make dlm debugging slightly easier.
+ *
+ * For more on lockname formats, please refer to dlmglue.c and ocfs2_lockid.h.
+ */
+static int stringify_lockname(const char *lockname, int locklen,
+                              char *buf, int len)
+{
+        int out = 0;
+        __be64 inode_blkno_be;
+
+#define OCFS2_DENTRY_LOCK_INO_START     18
+        if (*lockname == 'N') {
+                memcpy((__be64 *)&inode_blkno_be,
+                       (char *)&lockname[OCFS2_DENTRY_LOCK_INO_START],
+                       sizeof(__be64));
+                out += snprintf(buf + out, len - out, "%.*s%08x",
+                                OCFS2_DENTRY_LOCK_INO_START - 1, lockname,
+                                (unsigned int)be64_to_cpu(inode_blkno_be));
+        } else
+                out += snprintf(buf + out, len - out, "%.*s",
+                                locklen, lockname);
+        return out;
+}
+
 #define DLM_DEBUGFS_DIR                         "o2dlm"
 #define DLM_DEBUGFS_DLM_STATE                   "dlm_state"
+#define DLM_DEBUGFS_LOCKING_STATE               "locking_state"
 
 /* begin - utils funcs */
 static void dlm_debug_free(struct kref *kref)
@@ -368,6 +395,213 @@ static int debug_buffer_release(struct inode *inode, struct file *file)
 }
 /* end - util funcs */
 
+/* begin - debug lockres funcs */
+static int dump_lock(struct dlm_lock *lock, int list_type, char *buf, int len)
+{
+        int out;
+
+#define DEBUG_LOCK_VERSION      1
+        spin_lock(&lock->spinlock);
+        out = snprintf(buf, len, "LOCK:%d,%d,%d,%d,%d,%d:%lld,%d,%d,%d,%d,%d,"
+                       "%d,%d,%d,%d\n",
+                       DEBUG_LOCK_VERSION,
+                       list_type, lock->ml.type, lock->ml.convert_type,
+                       lock->ml.node,
+                       dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
+                       dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
+                       !list_empty(&lock->ast_list),
+                       !list_empty(&lock->bast_list),
+                       lock->ast_pending, lock->bast_pending,
+                       lock->convert_pending, lock->lock_pending,
+                       lock->cancel_pending, lock->unlock_pending,
+                       atomic_read(&lock->lock_refs.refcount));
+        spin_unlock(&lock->spinlock);
+
+        return out;
+}
+
+static int dump_lockres(struct dlm_lock_resource *res, char *buf, int len)
+{
+        struct dlm_lock *lock;
+        int i;
+        int out = 0;
+
+        out += snprintf(buf + out, len - out, "NAME:");
+        out += stringify_lockname(res->lockname.name, res->lockname.len,
+                                  buf + out, len - out);
+        out += snprintf(buf + out, len - out, "\n");
+
+#define DEBUG_LRES_VERSION      1
+        out += snprintf(buf + out, len - out,
+                        "LRES:%d,%d,%d,%ld,%d,%d,%d,%d,%d,%d,%d\n",
+                        DEBUG_LRES_VERSION,
+                        res->owner, res->state, res->last_used,
+                        !list_empty(&res->purge),
+                        !list_empty(&res->dirty),
+                        !list_empty(&res->recovering),
+                        res->inflight_locks, res->migration_pending,
+                        atomic_read(&res->asts_reserved),
+                        atomic_read(&res->refs.refcount));
+
+        /* refmap */
+        out += snprintf(buf + out, len - out, "RMAP:");
+        out += stringify_nodemap(res->refmap, O2NM_MAX_NODES,
+                                 buf + out, len - out);
+        out += snprintf(buf + out, len - out, "\n");
+
+        /* lvb */
+        out += snprintf(buf + out, len - out, "LVBX:");
+        for (i = 0; i < DLM_LVB_LEN; i++)
+                out += snprintf(buf + out, len - out,
+                                        "%02x", (unsigned char)res->lvb[i]);
+        out += snprintf(buf + out, len - out, "\n");
+
+        /* granted */
+        list_for_each_entry(lock, &res->granted, list)
+                out += dump_lock(lock, 0, buf + out, len - out);
+
+        /* converting */
+        list_for_each_entry(lock, &res->converting, list)
+                out += dump_lock(lock, 1, buf + out, len - out);
+
+        /* blocked */
+        list_for_each_entry(lock, &res->blocked, list)
+                out += dump_lock(lock, 2, buf + out, len - out);
+
+        out += snprintf(buf + out, len - out, "\n");
+
+        return out;
+}
+
+static void *lockres_seq_start(struct seq_file *m, loff_t *pos)
+{
+        struct debug_lockres *dl = m->private;
+        struct dlm_ctxt *dlm = dl->dl_ctxt;
+        struct dlm_lock_resource *res = NULL;
+
+        spin_lock(&dlm->spinlock);
+
+        if (dl->dl_res) {
+                list_for_each_entry(res, &dl->dl_res->tracking, tracking) {
+                        if (dl->dl_res) {
+                                dlm_lockres_put(dl->dl_res);
+                                dl->dl_res = NULL;
+                        }
+                        if (&res->tracking == &dlm->tracking_list) {
+                                mlog(0, "End of list found, %p\n", res);
+                                dl = NULL;
+                                break;
+                        }
+                        dlm_lockres_get(res);
+                        dl->dl_res = res;
+                        break;
+                }
+        } else {
+                if (!list_empty(&dlm->tracking_list)) {
+                        list_for_each_entry(res, &dlm->tracking_list, tracking)
+                                break;
+                        dlm_lockres_get(res);
+                        dl->dl_res = res;
+                } else
+                        dl = NULL;
+        }
+
+        if (dl) {
+                spin_lock(&dl->dl_res->spinlock);
+                dump_lockres(dl->dl_res, dl->dl_buf, dl->dl_len - 1);
+                spin_unlock(&dl->dl_res->spinlock);
+        }
+
+        spin_unlock(&dlm->spinlock);
+
+        return dl;
+}
+
+static void lockres_seq_stop(struct seq_file *m, void *v)
+{
+}
+
+static void *lockres_seq_next(struct seq_file *m, void *v, loff_t *pos)
+{
+        return NULL;
+}
+
+static int lockres_seq_show(struct seq_file *s, void *v)
+{
+        struct debug_lockres *dl = (struct debug_lockres *)v;
+
+        seq_printf(s, "%s", dl->dl_buf);
+
+        return 0;
+}
+
+static struct seq_operations debug_lockres_ops = {
+        .start =        lockres_seq_start,
+        .stop =         lockres_seq_stop,
+        .next =         lockres_seq_next,
+        .show =         lockres_seq_show,
+};
+
+static int debug_lockres_open(struct inode *inode, struct file *file)
+{
+        struct dlm_ctxt *dlm = inode->i_private;
+        int ret = -ENOMEM;
+        struct seq_file *seq;
+        struct debug_lockres *dl = NULL;
+
+        dl = kzalloc(sizeof(struct debug_lockres), GFP_KERNEL);
+        if (!dl) {
+                mlog_errno(ret);
+                goto bail;
+        }
+
+        dl->dl_len = PAGE_SIZE;
+        dl->dl_buf = kmalloc(dl->dl_len, GFP_KERNEL);
+        if (!dl->dl_buf) {
+                mlog_errno(ret);
+                goto bail;
+        }
+
+        ret = seq_open(file, &debug_lockres_ops);
+        if (ret) {
+                mlog_errno(ret);
+                goto bail;
+        }
+
+        seq = (struct seq_file *) file->private_data;
+        seq->private = dl;
+
+        dlm_grab(dlm);
+        dl->dl_ctxt = dlm;
+
+        return 0;
+bail:
+        if (dl)
+                kfree(dl->dl_buf);
+        kfree(dl);
+        return ret;
+}
+
+static int debug_lockres_release(struct inode *inode, struct file *file)
+{
+        struct seq_file *seq = (struct seq_file *)file->private_data;
+        struct debug_lockres *dl = (struct debug_lockres *)seq->private;
+
+        if (dl->dl_res)
+                dlm_lockres_put(dl->dl_res);
+        dlm_put(dl->dl_ctxt);
+        kfree(dl->dl_buf);
+        return seq_release_private(inode, file);
+}
+
+static struct file_operations debug_lockres_fops = {
+        .open =         debug_lockres_open,
+        .release =      debug_lockres_release,
+        .read =         seq_read,
+        .llseek =       seq_lseek,
+};
+/* end - debug lockres funcs */
+
 /* begin - debug state funcs */
 static int debug_state_print(struct dlm_ctxt *dlm, struct debug_buffer *db)
 {
@@ -544,6 +778,17 @@ int dlm_debug_init(struct dlm_ctxt *dlm)
                 goto bail;
         }
 
+        /* for dumping lockres */
+        dc->debug_lockres_dentry =
+                        debugfs_create_file(DLM_DEBUGFS_LOCKING_STATE,
+                                            S_IFREG|S_IRUSR,
+                                            dlm->dlm_debugfs_subroot,
+                                            dlm, &debug_lockres_fops);
+        if (!dc->debug_lockres_dentry) {
+                mlog_errno(-ENOMEM);
+                goto bail;
+        }
+
         dlm_debug_get(dc);
         return 0;
 
@@ -557,6 +802,8 @@ void dlm_debug_shutdown(struct dlm_ctxt *dlm)
         struct dlm_debug_ctxt *dc = dlm->dlm_debug_ctxt;
 
         if (dc) {
+                if (dc->debug_lockres_dentry)
+                        debugfs_remove(dc->debug_lockres_dentry);
                 if (dc->debug_state_dentry)
                         debugfs_remove(dc->debug_state_dentry);
                 dlm_debug_put(dc);
diff --git a/fs/ocfs2/dlm/dlmdebug.h b/fs/ocfs2/dlm/dlmdebug.h
index 94cc10a4e19c..7c5b2b0a05ed 100644
--- a/fs/ocfs2/dlm/dlmdebug.h
+++ b/fs/ocfs2/dlm/dlmdebug.h
@@ -30,6 +30,7 @@
 struct dlm_debug_ctxt {
         struct kref debug_refcnt;
         struct dentry *debug_state_dentry;
+        struct dentry *debug_lockres_dentry;
 };
 
 struct debug_buffer {
@@ -37,6 +38,13 @@ struct debug_buffer {
         char *buf;
 };
 
+struct debug_lockres {
+        int dl_len;
+        char *dl_buf;
+        struct dlm_ctxt *dl_ctxt;
+        struct dlm_lock_resource *dl_res;
+};
+
 int dlm_debug_init(struct dlm_ctxt *dlm);
 void dlm_debug_shutdown(struct dlm_ctxt *dlm);