drbd: debugfs: add per volume oldest_requests

Show oldest requests
 * pending master bio completion and,
 * if different, local disk bio completion.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

2 files changed, 160 insertions, 14 deletions

diff --git a/drivers/block/drbd/drbd_debugfs.c b/drivers/block/drbd/drbd_debugfs.c
index 230d9e1fc85c..45b52056f88d 100644
--- a/drivers/block/drbd/drbd_debugfs.c
+++ b/drivers/block/drbd/drbd_debugfs.c
@@ -434,12 +434,10 @@ static int drbd_single_open(struct file *file, int (*show)(struct seq_file *, vo
                 goto out;
         /* serialize with d_delete() */
         mutex_lock(&parent->d_inode->i_mutex);
-        if (!debugfs_positive(file->f_dentry))
-                goto out_unlock;
         /* Make sure the object is still alive */
-        if (kref_get_unless_zero(kref))
+        if (debugfs_positive(file->f_dentry)
+        && kref_get_unless_zero(kref))
                 ret = 0;
-out_unlock:
         mutex_unlock(&parent->d_inode->i_mutex);
         if (!ret) {
                 ret = single_open(file, show, data);
@@ -592,6 +590,53 @@ static const struct file_operations connection_callback_history_fops = {
         .release        = callback_history_release,
 };
 
+static int connection_oldest_requests_show(struct seq_file *m, void *ignored)
+{
+        struct drbd_connection *connection = m->private;
+        unsigned long now = jiffies;
+        struct drbd_request *r1, *r2;
+
+        /* BUMP me if you change the file format/content/presentation */
+        seq_printf(m, "v: %u\n\n", 0);
+
+        spin_lock_irq(&connection->resource->req_lock);
+        r1 = connection->req_next;
+        if (r1)
+                seq_print_minor_vnr_req(m, r1, now);
+        r2 = connection->req_ack_pending;
+        if (r2 && r2 != r1) {
+                r1 = r2;
+                seq_print_minor_vnr_req(m, r1, now);
+        }
+        r2 = connection->req_not_net_done;
+        if (r2 && r2 != r1)
+                seq_print_minor_vnr_req(m, r2, now);
+        spin_unlock_irq(&connection->resource->req_lock);
+        return 0;
+}
+
+static int connection_oldest_requests_open(struct inode *inode, struct file *file)
+{
+        struct drbd_connection *connection = inode->i_private;
+        return drbd_single_open(file, connection_oldest_requests_show, connection,
+                                &connection->kref, drbd_destroy_connection);
+}
+
+static int connection_oldest_requests_release(struct inode *inode, struct file *file)
+{
+        struct drbd_connection *connection = inode->i_private;
+        kref_put(&connection->kref, drbd_destroy_connection);
+        return single_release(inode, file);
+}
+
+static const struct file_operations connection_oldest_requests_fops = {
+        .owner          = THIS_MODULE,
+        .open           = connection_oldest_requests_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = connection_oldest_requests_release,
+};
+
 void drbd_debugfs_connection_add(struct drbd_connection *connection)
 {
         struct dentry *conns_dir = connection->resource->debugfs_res_connections;
@@ -627,6 +672,89 @@ void drbd_debugfs_connection_cleanup(struct drbd_connection *connection)
         drbd_debugfs_remove(&connection->debugfs_conn);
 }
 
+static void resync_dump_detail(struct seq_file *m, struct lc_element *e)
+{
+       struct bm_extent *bme = lc_entry(e, struct bm_extent, lce);
+
+       seq_printf(m, "%5d %s %s %s\n", bme->rs_left,
+                  test_bit(BME_NO_WRITES, &bme->flags) ? "NO_WRITES" : "---------",
+                  test_bit(BME_LOCKED, &bme->flags) ? "LOCKED" : "------",
+                  test_bit(BME_PRIORITY, &bme->flags) ? "PRIORITY" : "--------"
+                  );
+}
+
+static int device_resync_extents_show(struct seq_file *m, void *ignored)
+{
+        struct drbd_device *device = m->private;
+        if (get_ldev_if_state(device, D_FAILED)) {
+                lc_seq_printf_stats(m, device->resync);
+                lc_seq_dump_details(m, device->resync, "rs_left flags", resync_dump_detail);
+                put_ldev(device);
+        }
+        return 0;
+}
+
+static int device_act_log_extents_show(struct seq_file *m, void *ignored)
+{
+        struct drbd_device *device = m->private;
+        if (get_ldev_if_state(device, D_FAILED)) {
+                lc_seq_printf_stats(m, device->act_log);
+                lc_seq_dump_details(m, device->act_log, "", NULL);
+                put_ldev(device);
+        }
+        return 0;
+}
+
+static int device_oldest_requests_show(struct seq_file *m, void *ignored)
+{
+        struct drbd_device *device = m->private;
+        struct drbd_resource *resource = device->resource;
+        unsigned long now = jiffies;
+        struct drbd_request *r1, *r2;
+        int i;
+
+        seq_puts(m, RQ_HDR);
+        spin_lock_irq(&resource->req_lock);
+        /* WRITE, then READ */
+        for (i = 1; i >= 0; --i) {
+                r1 = list_first_entry_or_null(&device->pending_master_completion[i],
+                        struct drbd_request, req_pending_master_completion);
+                r2 = list_first_entry_or_null(&device->pending_completion[i],
+                        struct drbd_request, req_pending_local);
+                if (r1)
+                        seq_print_one_request(m, r1, now);
+                if (r2 && r2 != r1)
+                        seq_print_one_request(m, r2, now);
+        }
+        spin_unlock_irq(&resource->req_lock);
+        return 0;
+}
+
+#define drbd_debugfs_device_attr(name)                                          \
+static int device_ ## name ## _open(struct inode *inode, struct file *file)     \
+{                                                                               \
+        struct drbd_device *device = inode->i_private;                          \
+        return drbd_single_open(file, device_ ## name ## _show, device,         \
+                                &device->kref, drbd_destroy_device);            \
+}                                                                               \
+static int device_ ## name ## _release(struct inode *inode, struct file *file)  \
+{                                                                               \
+        struct drbd_device *device = inode->i_private;                          \
+        kref_put(&device->kref, drbd_destroy_device);                           \
+        return single_release(inode, file);                                     \
+}                                                                               \
+static const struct file_operations device_ ## name ## _fops = {                \
+        .owner          = THIS_MODULE,                                          \
+        .open           = device_ ## name ## _open,                             \
+        .read           = seq_read,                                             \
+        .llseek         = seq_lseek,                                            \
+        .release        = device_ ## name ## _release,                          \
+};
+
+drbd_debugfs_device_attr(oldest_requests)
+drbd_debugfs_device_attr(act_log_extents)
+drbd_debugfs_device_attr(resync_extents)
+
 void drbd_debugfs_device_add(struct drbd_device *device)
 {
         struct dentry *vols_dir = device->resource->debugfs_res_volumes;
@@ -650,10 +778,25 @@ void drbd_debugfs_device_add(struct drbd_device *device)
         if (!slink_name)
                 goto fail;
         dentry = debugfs_create_symlink(minor_buf, drbd_debugfs_minors, slink_name);
+        kfree(slink_name);
+        slink_name = NULL;
         if (IS_ERR_OR_NULL(dentry))
                 goto fail;
         device->debugfs_minor = dentry;
-        kfree(slink_name);
+
+#define DCF(name)       do {                                    \
+        dentry = debugfs_create_file(#name, S_IRUSR|S_IRGRP,    \
+                        device->debugfs_vol, device,            \
+                        &device_ ## name ## _fops);             \
+        if (IS_ERR_OR_NULL(dentry))                             \
+                goto fail;                                      \
+        device->debugfs_vol_ ## name = dentry;                  \
+        } while (0)
+
+        DCF(oldest_requests);
+        DCF(act_log_extents);
+        DCF(resync_extents);
+        return;
 
 fail:
         drbd_debugfs_device_cleanup(device);
diff --git a/lib/lru_cache.c b/lib/lru_cache.c
index 6111cd19762d..852c81e3ba9a 100644
--- a/lib/lru_cache.c
+++ b/lib/lru_cache.c
@@ -643,9 +643,10 @@ void lc_set(struct lru_cache *lc, unsigned int enr, int index)
  * lc_dump - Dump a complete LRU cache to seq in textual form.
  * @lc: the lru cache to operate on
  * @seq: the &struct seq_file pointer to seq_printf into
- * @utext: user supplied "heading" or other info
+ * @utext: user supplied additional "heading" or other info
  * @detail: function pointer the user may provide to dump further details
- * of the object the lc_element is embedded in.
+ * of the object the lc_element is embedded in. May be NULL.
+ * Note: a leading space ' ' and trailing newline '\n' is implied.
  */
 void lc_seq_dump_details(struct seq_file *seq, struct lru_cache *lc, char *utext,
              void (*detail) (struct seq_file *, struct lc_element *))
@@ -654,16 +655,18 @@ void lc_seq_dump_details(struct seq_file *seq, struct lru_cache *lc, char *utext
         struct lc_element *e;
         int i;
 
-        seq_printf(seq, "\tnn: lc_number refcnt %s\n ", utext);
+        seq_printf(seq, "\tnn: lc_number (new nr) refcnt %s\n ", utext);
         for (i = 0; i < nr_elements; i++) {
                 e = lc_element_by_index(lc, i);
-                if (e->lc_number == LC_FREE) {
-                        seq_printf(seq, "\t%2d: FREE\n", i);
-                } else {
-                        seq_printf(seq, "\t%2d: %4u %4u    ", i,
-                                   e->lc_number, e->refcnt);
+                if (e->lc_number != e->lc_new_number)
+                        seq_printf(seq, "\t%5d: %6d %8d %6d ",
+                                i, e->lc_number, e->lc_new_number, e->refcnt);
+                else
+                        seq_printf(seq, "\t%5d: %6d %-8s %6d ",
+                                i, e->lc_number, "-\"-", e->refcnt);
+                if (detail)
                         detail(seq, e);
-                }
+                seq_putc(seq, '\n');
         }
 }