Quelle  drbd_debugfs.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
#define pr_fmt(fmt) "drbd debugfs: " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/stat.h>
#include <linux/jiffies.h>
#include <linux/list.h>

#include "drbd_int.h"
#include "drbd_req.h"
#include "drbd_debugfs.h"


/**********************************************************************
 * Whenever you change the file format, remember to bump the version. *
 **********************************************************************/

static struct dentry *drbd_debugfs_root;
static struct dentry *drbd_debugfs_version;
static struct dentry *drbd_debugfs_resources;
static struct dentry *drbd_debugfs_minors;

static void seq_print_age_or_dash(struct seq_file *m, bool valid, unsigned long dt)
{
 if (valid)
  seq_printf(m, "\t%d", jiffies_to_msecs(dt));
 else
  seq_printf(m, "\t-");
}

static void __seq_print_rq_state_bit(struct seq_file *m,
 bool is_set, char *sep, const char *set_name, const char *unset_name)
{
 if (is_set && set_name) {
  seq_putc(m, *sep);
  seq_puts(m, set_name);
  *sep = '|';
 } else if (!is_set && unset_name) {
  seq_putc(m, *sep);
  seq_puts(m, unset_name);
  *sep = '|';
 }
}

static void seq_print_rq_state_bit(struct seq_file *m,
 bool is_set, char *sep, const char *set_name)
{
 __seq_print_rq_state_bit(m, is_set, sep, set_name, NULL);
}

/* pretty print enum drbd_req_state_bits req->rq_state */
static void seq_print_request_state(struct seq_file *m, struct drbd_request *req)
{
 unsigned int s = req->rq_state;
 char sep = ' ';
 seq_printf(m, "\t0x%08x", s);
 seq_printf(m, "\tmaster: %s", req->master_bio ? "pending" : "completed");

 /* RQ_WRITE ignored, already reported */
 seq_puts(m, "\tlocal:");
 seq_print_rq_state_bit(m, s & RQ_IN_ACT_LOG, &sep, "in-AL");
 seq_print_rq_state_bit(m, s & RQ_POSTPONED, &sep, "postponed");
 seq_print_rq_state_bit(m, s & RQ_COMPLETION_SUSP, &sep, "suspended");
 sep = ' ';
 seq_print_rq_state_bit(m, s & RQ_LOCAL_PENDING, &sep, "pending");
 seq_print_rq_state_bit(m, s & RQ_LOCAL_COMPLETED, &sep, "completed");
 seq_print_rq_state_bit(m, s & RQ_LOCAL_ABORTED, &sep, "aborted");
 seq_print_rq_state_bit(m, s & RQ_LOCAL_OK, &sep, "ok");
 if (sep == ' ')
  seq_puts(m, " -");

 /* for_each_connection ... */
 seq_printf(m, "\tnet:");
 sep = ' ';
 seq_print_rq_state_bit(m, s & RQ_NET_PENDING, &sep, "pending");
 seq_print_rq_state_bit(m, s & RQ_NET_QUEUED, &sep, "queued");
 seq_print_rq_state_bit(m, s & RQ_NET_SENT, &sep, "sent");
 seq_print_rq_state_bit(m, s & RQ_NET_DONE, &sep, "done");
 seq_print_rq_state_bit(m, s & RQ_NET_SIS, &sep, "sis");
 seq_print_rq_state_bit(m, s & RQ_NET_OK, &sep, "ok");
 if (sep == ' ')
  seq_puts(m, " -");

 seq_printf(m, " :");
 sep = ' ';
 seq_print_rq_state_bit(m, s & RQ_EXP_RECEIVE_ACK, &sep, "B");
 seq_print_rq_state_bit(m, s & RQ_EXP_WRITE_ACK, &sep, "C");
 seq_print_rq_state_bit(m, s & RQ_EXP_BARR_ACK, &sep, "barr");
 if (sep == ' ')
  seq_puts(m, " -");
 seq_printf(m, "\n");
}

static void seq_print_one_request(struct seq_file *m, struct drbd_request *req, unsigned long now)
{
 /* change anything here, fixup header below! */
 unsigned int s = req->rq_state;

#define RQ_HDR_1 "epoch\tsector\tsize\trw"
 seq_printf(m, "0x%x\t%llu\t%u\t%s",
  req->epoch,
  (unsigned long long)req->i.sector, req->i.size >> 9,
  (s & RQ_WRITE) ? "W" : "R");

#define RQ_HDR_2 "\tstart\tin AL\tsubmit"
 seq_printf(m, "\t%d", jiffies_to_msecs(now - req->start_jif));
 seq_print_age_or_dash(m, s & RQ_IN_ACT_LOG, now - req->in_actlog_jif);
 seq_print_age_or_dash(m, s & RQ_LOCAL_PENDING, now - req->pre_submit_jif);

#define RQ_HDR_3 "\tsent\tacked\tdone"
 seq_print_age_or_dash(m, s & RQ_NET_SENT, now - req->pre_send_jif);
 seq_print_age_or_dash(m, (s & RQ_NET_SENT) && !(s & RQ_NET_PENDING), now - req->acked_jif);
 seq_print_age_or_dash(m, s & RQ_NET_DONE, now - req->net_done_jif);

#define RQ_HDR_4 "\tstate\n"
 seq_print_request_state(m, req);
}
#define RQ_HDR RQ_HDR_1 RQ_HDR_2 RQ_HDR_3 RQ_HDR_4

static void seq_print_minor_vnr_req(struct seq_file *m, struct drbd_request *req, unsigned long now)
{
 seq_printf(m, "%u\t%u\t", req->device->minor, req->device->vnr);
 seq_print_one_request(m, req, now);
}

static void seq_print_resource_pending_meta_io(struct seq_file *m, struct drbd_resource *resource, unsigned long now)
{
 struct drbd_device *device;
 unsigned int i;

 seq_puts(m, "minor\tvnr\tstart\tsubmit\tintent\n");
 rcu_read_lock();
 idr_for_each_entry(&resource->devices, device, i) {
  struct drbd_md_io tmp;
  /* In theory this is racy,
 * in the sense that there could have been a
 * drbd_md_put_buffer(); drbd_md_get_buffer();
 * between accessing these members here.  */
  tmp = device->md_io;
  if (atomic_read(&tmp.in_use)) {
   seq_printf(m, "%u\t%u\t%d\t",
    device->minor, device->vnr,
    jiffies_to_msecs(now - tmp.start_jif));
   if (time_before(tmp.submit_jif, tmp.start_jif))
    seq_puts(m, "-\t");
   else
    seq_printf(m, "%d\t", jiffies_to_msecs(now - tmp.submit_jif));
   seq_printf(m, "%s\n", tmp.current_use);
  }
 }
 rcu_read_unlock();
}

static void seq_print_waiting_for_AL(struct seq_file *m, struct drbd_resource *resource, unsigned long now)
{
 struct drbd_device *device;
 unsigned int i;

 seq_puts(m, "minor\tvnr\tage\t#waiting\n");
 rcu_read_lock();
 idr_for_each_entry(&resource->devices, device, i) {
  unsigned long jif;
  struct drbd_request *req;
  int n = atomic_read(&device->ap_actlog_cnt);
  if (n) {
   spin_lock_irq(&device->resource->req_lock);
   req = list_first_entry_or_null(&device->pending_master_completion[1],
    struct drbd_request, req_pending_master_completion);
   /* if the oldest request does not wait for the activity log
 * it is not interesting for us here */
   if (req && !(req->rq_state & RQ_IN_ACT_LOG))
    jif = req->start_jif;
   else
    req = NULL;
   spin_unlock_irq(&device->resource->req_lock);
  }
  if (n) {
   seq_printf(m, "%u\t%u\t", device->minor, device->vnr);
   if (req)
    seq_printf(m, "%u\t", jiffies_to_msecs(now - jif));
   else
    seq_puts(m, "-\t");
   seq_printf(m, "%u\n", n);
  }
 }
 rcu_read_unlock();
}

static void seq_print_device_bitmap_io(struct seq_file *m, struct drbd_device *device, unsigned long now)
{
 struct drbd_bm_aio_ctx *ctx;
 unsigned long start_jif;
 unsigned int in_flight;
 unsigned int flags;
 spin_lock_irq(&device->resource->req_lock);
 ctx = list_first_entry_or_null(&device->pending_bitmap_io, struct drbd_bm_aio_ctx, list);
 if (ctx && ctx->done)
  ctx = NULL;
 if (ctx) {
  start_jif = ctx->start_jif;
  in_flight = atomic_read(&ctx->in_flight);
  flags = ctx->flags;
 }
 spin_unlock_irq(&device->resource->req_lock);
 if (ctx) {
  seq_printf(m, "%u\t%u\t%c\t%u\t%u\n",
   device->minor, device->vnr,
   (flags & BM_AIO_READ) ? 'R' : 'W',
   jiffies_to_msecs(now - start_jif),
   in_flight);
 }
}

static void seq_print_resource_pending_bitmap_io(struct seq_file *m, struct drbd_resource *resource, unsigned long now)
{
 struct drbd_device *device;
 unsigned int i;

 seq_puts(m, "minor\tvnr\trw\tage\t#in-flight\n");
 rcu_read_lock();
 idr_for_each_entry(&resource->devices, device, i) {
  seq_print_device_bitmap_io(m, device, now);
 }
 rcu_read_unlock();
}

/* pretty print enum peer_req->flags */
static void seq_print_peer_request_flags(struct seq_file *m, struct drbd_peer_request *peer_req)
{
 unsigned long f = peer_req->flags;
 char sep = ' ';

 __seq_print_rq_state_bit(m, f & EE_SUBMITTED, &sep, "submitted", "preparing");
 __seq_print_rq_state_bit(m, f & EE_APPLICATION, &sep, "application", "internal");
 seq_print_rq_state_bit(m, f & EE_CALL_AL_COMPLETE_IO, &sep, "in-AL");
 seq_print_rq_state_bit(m, f & EE_SEND_WRITE_ACK, &sep, "C");
 seq_print_rq_state_bit(m, f & EE_MAY_SET_IN_SYNC, &sep, "set-in-sync");
 seq_print_rq_state_bit(m, f & EE_TRIM, &sep, "trim");
 seq_print_rq_state_bit(m, f & EE_ZEROOUT, &sep, "zero-out");
 seq_print_rq_state_bit(m, f & EE_WRITE_SAME, &sep, "write-same");
 seq_putc(m, '\n');
}

static void seq_print_peer_request(struct seq_file *m,
 struct drbd_device *device, struct list_head *lh,
 unsigned long now)
{
 bool reported_preparing = false;
 struct drbd_peer_request *peer_req;
 list_for_each_entry(peer_req, lh, w.list) {
  if (reported_preparing && !(peer_req->flags & EE_SUBMITTED))
   continue;

  if (device)
   seq_printf(m, "%u\t%u\t", device->minor, device->vnr);

  seq_printf(m, "%llu\t%u\t%c\t%u\t",
   (unsigned long long)peer_req->i.sector, peer_req->i.size >> 9,
   (peer_req->flags & EE_WRITE) ? 'W' : 'R',
   jiffies_to_msecs(now - peer_req->submit_jif));
  seq_print_peer_request_flags(m, peer_req);
  if (peer_req->flags & EE_SUBMITTED)
   break;
  else
   reported_preparing = true;
 }
}

static void seq_print_device_peer_requests(struct seq_file *m,
 struct drbd_device *device, unsigned long now)
{
 seq_puts(m, "minor\tvnr\tsector\tsize\trw\tage\tflags\n");
 spin_lock_irq(&device->resource->req_lock);
 seq_print_peer_request(m, device, &device->active_ee, now);
 seq_print_peer_request(m, device, &device->read_ee, now);
 seq_print_peer_request(m, device, &device->sync_ee, now);
 spin_unlock_irq(&device->resource->req_lock);
 if (test_bit(FLUSH_PENDING, &device->flags)) {
  seq_printf(m, "%u\t%u\t-\t-\tF\t%u\tflush\n",
   device->minor, device->vnr,
   jiffies_to_msecs(now - device->flush_jif));
 }
}

static void seq_print_resource_pending_peer_requests(struct seq_file *m,
 struct drbd_resource *resource, unsigned long now)
{
 struct drbd_device *device;
 unsigned int i;

 rcu_read_lock();
 idr_for_each_entry(&resource->devices, device, i) {
  seq_print_device_peer_requests(m, device, now);
 }
 rcu_read_unlock();
}

static void seq_print_resource_transfer_log_summary(struct seq_file *m,
 struct drbd_resource *resource,
 struct drbd_connection *connection,
 unsigned long now)
{
 struct drbd_request *req;
 unsigned int count = 0;
 unsigned int show_state = 0;

 seq_puts(m, "n\tdevice\tvnr\t" RQ_HDR);
 spin_lock_irq(&resource->req_lock);
 list_for_each_entry(req, &connection->transfer_log, tl_requests) {
  unsigned int tmp = 0;
  unsigned int s;
  ++count;

  /* don't disable irq "forever" */
  if (!(count & 0x1ff)) {
   struct drbd_request *req_next;
   kref_get(&req->kref);
   spin_unlock_irq(&resource->req_lock);
   cond_resched();
   spin_lock_irq(&resource->req_lock);
   req_next = list_next_entry(req, tl_requests);
   if (kref_put(&req->kref, drbd_req_destroy))
    req = req_next;
   if (&req->tl_requests == &connection->transfer_log)
    break;
  }

  s = req->rq_state;

  /* This is meant to summarize timing issues, to be able to tell
 * local disk problems from network problems.
 * Skip requests, if we have shown an even older request with
 * similar aspects already.  */
  if (req->master_bio == NULL)
   tmp |= 1;
  if ((s & RQ_LOCAL_MASK) && (s & RQ_LOCAL_PENDING))
   tmp |= 2;
  if (s & RQ_NET_MASK) {
   if (!(s & RQ_NET_SENT))
    tmp |= 4;
   if (s & RQ_NET_PENDING)
    tmp |= 8;
   if (!(s & RQ_NET_DONE))
    tmp |= 16;
  }
  if ((tmp & show_state) == tmp)
   continue;
  show_state |= tmp;
  seq_printf(m, "%u\t", count);
  seq_print_minor_vnr_req(m, req, now);
  if (show_state == 0x1f)
   break;
 }
 spin_unlock_irq(&resource->req_lock);
}

/* TODO: transfer_log and friends should be moved to resource */
static int in_flight_summary_show(struct seq_file *m, void *pos)
{
 struct drbd_resource *resource = m->private;
 struct drbd_connection *connection;
 unsigned long jif = jiffies;

 connection = first_connection(resource);
 /* This does not happen, actually.
 * But be robust and prepare for future code changes. */
 if (!connection || !kref_get_unless_zero(&connection->kref))
  return -ESTALE;

 /* BUMP me if you change the file format/content/presentation */
 seq_printf(m, "v: %u\n\n", 0);

 seq_puts(m, "oldest bitmap IO\n");
 seq_print_resource_pending_bitmap_io(m, resource, jif);
 seq_putc(m, '\n');

 seq_puts(m, "meta data IO\n");
 seq_print_resource_pending_meta_io(m, resource, jif);
 seq_putc(m, '\n');

 seq_puts(m, "socket buffer stats\n");
 /* for each connection ... once we have more than one */
 rcu_read_lock();
 if (connection->data.socket) {
  /* open coded SIOCINQ, the "relevant" part */
  struct tcp_sock *tp = tcp_sk(connection->data.socket->sk);
  int answ = tp->rcv_nxt - tp->copied_seq;
  seq_printf(m, "unread receive buffer: %u Byte\n", answ);
  /* open coded SIOCOUTQ, the "relevant" part */
  answ = tp->write_seq - tp->snd_una;
  seq_printf(m, "unacked send buffer: %u Byte\n", answ);
 }
 rcu_read_unlock();
 seq_putc(m, '\n');

 seq_puts(m, "oldest peer requests\n");
 seq_print_resource_pending_peer_requests(m, resource, jif);
 seq_putc(m, '\n');

 seq_puts(m, "application requests waiting for activity log\n");
 seq_print_waiting_for_AL(m, resource, jif);
 seq_putc(m, '\n');

 seq_puts(m, "oldest application requests\n");
 seq_print_resource_transfer_log_summary(m, resource, connection, jif);
 seq_putc(m, '\n');

 jif = jiffies - jif;
 if (jif)
  seq_printf(m, "generated in %d ms\n", jiffies_to_msecs(jif));
 kref_put(&connection->kref, drbd_destroy_connection);
 return 0;
}

/* make sure at *open* time that the respective object won't go away. */
static int drbd_single_open(struct file *file, int (*show)(struct seq_file *, void *),
                  void *data, struct kref *kref,
    void (*release)(struct kref *))
{
 struct dentry *parent;
 int ret = -ESTALE;

 /* Are we still linked,
 * or has debugfs_remove() already been called? */
 parent = file->f_path.dentry->d_parent;
 /* serialize with d_delete() */
 inode_lock(d_inode(parent));
 /* Make sure the object is still alive */
 if (simple_positive(file->f_path.dentry)
 && kref_get_unless_zero(kref))
  ret = 0;
 inode_unlock(d_inode(parent));
 if (!ret) {
  ret = single_open(file, show, data);
  if (ret)
   kref_put(kref, release);
 }
 return ret;
}

static int in_flight_summary_open(struct inode *inode, struct file *file)
{
 struct drbd_resource *resource = inode->i_private;
 return drbd_single_open(file, in_flight_summary_show, resource,
    &resource->kref, drbd_destroy_resource);
}

static int in_flight_summary_release(struct inode *inode, struct file *file)
{
 struct drbd_resource *resource = inode->i_private;
 kref_put(&resource->kref, drbd_destroy_resource);
 return single_release(inode, file);
}

static const struct file_operations in_flight_summary_fops = {
 .owner  = THIS_MODULE,
 .open  = in_flight_summary_open,
 .read  = seq_read,
 .llseek  = seq_lseek,
 .release = in_flight_summary_release,
};

void drbd_debugfs_resource_add(struct drbd_resource *resource)
{
 struct dentry *dentry;

 dentry = debugfs_create_dir(resource->name, drbd_debugfs_resources);
 resource->debugfs_res = dentry;

 dentry = debugfs_create_dir("volumes", resource->debugfs_res);
 resource->debugfs_res_volumes = dentry;

 dentry = debugfs_create_dir("connections", resource->debugfs_res);
 resource->debugfs_res_connections = dentry;

 dentry = debugfs_create_file("in_flight_summary", 0440,
         resource->debugfs_res, resource,
         &in_flight_summary_fops);
 resource->debugfs_res_in_flight_summary = dentry;
}

static void drbd_debugfs_remove(struct dentry **dp)
{
 debugfs_remove(*dp);
 *dp = NULL;
}

void drbd_debugfs_resource_cleanup(struct drbd_resource *resource)
{
 /* it is ok to call debugfs_remove(NULL) */
 drbd_debugfs_remove(&resource->debugfs_res_in_flight_summary);
 drbd_debugfs_remove(&resource->debugfs_res_connections);
 drbd_debugfs_remove(&resource->debugfs_res_volumes);
 drbd_debugfs_remove(&resource->debugfs_res);
}

static void seq_print_one_timing_detail(struct seq_file *m,
 const struct drbd_thread_timing_details *tdp,
 unsigned long now)
{
 struct drbd_thread_timing_details td;
 /* No locking...
 * use temporary assignment to get at consistent data. */
 do {
  td = *tdp;
 } while (td.cb_nr != tdp->cb_nr);
 if (!td.cb_addr)
  return;
 seq_printf(m, "%u\t%d\t%s:%u\t%ps\n",
   td.cb_nr,
   jiffies_to_msecs(now - td.start_jif),
   td.caller_fn, td.line,
   td.cb_addr);
}

static void seq_print_timing_details(struct seq_file *m,
  const char *title,
  unsigned int cb_nr, struct drbd_thread_timing_details *tdp, unsigned long now)
{
 unsigned int start_idx;
 unsigned int i;

 seq_printf(m, "%s\n", title);
 /* If not much is going on, this will result in natural ordering.
 * If it is very busy, we will possibly skip events, or even see wrap
 * arounds, which could only be avoided with locking.
 */
 start_idx = cb_nr % DRBD_THREAD_DETAILS_HIST;
 for (i = start_idx; i < DRBD_THREAD_DETAILS_HIST; i++)
  seq_print_one_timing_detail(m, tdp+i, now);
 for (i = 0; i < start_idx; i++)
  seq_print_one_timing_detail(m, tdp+i, now);
}

static int callback_history_show(struct seq_file *m, void *ignored)
{
 struct drbd_connection *connection = m->private;
 unsigned long jif = jiffies;

 /* BUMP me if you change the file format/content/presentation */
 seq_printf(m, "v: %u\n\n", 0);

 seq_puts(m, "n\tage\tcallsite\tfn\n");
 seq_print_timing_details(m, "worker", connection->w_cb_nr, connection->w_timing_details, jif);
 seq_print_timing_details(m, "receiver", connection->r_cb_nr, connection->r_timing_details, jif);
 return 0;
}

static int callback_history_open(struct inode *inode, struct file *file)
{
 struct drbd_connection *connection = inode->i_private;
 return drbd_single_open(file, callback_history_show, connection,
    &connection->kref, drbd_destroy_connection);
}

static int callback_history_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_callback_history_fops = {
 .owner  = THIS_MODULE,
 .open  = callback_history_open,
 .read  = seq_read,
 .llseek  = seq_lseek,
 .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;
 struct dentry *dentry;

 /* Once we enable mutliple peers,
 * these connections will have descriptive names.
 * For now, it is just the one connection to the (only) "peer". */
 dentry = debugfs_create_dir("peer", conns_dir);
 connection->debugfs_conn = dentry;

 dentry = debugfs_create_file("callback_history", 0440,
         connection->debugfs_conn, connection,
         &connection_callback_history_fops);
 connection->debugfs_conn_callback_history = dentry;

 dentry = debugfs_create_file("oldest_requests", 0440,
         connection->debugfs_conn, connection,
         &connection_oldest_requests_fops);
 connection->debugfs_conn_oldest_requests = dentry;
}

void drbd_debugfs_connection_cleanup(struct drbd_connection *connection)
{
 drbd_debugfs_remove(&connection->debugfs_conn_callback_history);
 drbd_debugfs_remove(&connection->debugfs_conn_oldest_requests);
 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", 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;

 /* BUMP me if you change the file format/content/presentation */
 seq_printf(m, "v: %u\n\n", 0);

 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;

 /* BUMP me if you change the file format/content/presentation */
 seq_printf(m, "v: %u\n\n", 0);

 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;

 /* BUMP me if you change the file format/content/presentation */
 seq_printf(m, "v: %u\n\n", 0);

 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;
}

static int device_data_gen_id_show(struct seq_file *m, void *ignored)
{
 struct drbd_device *device = m->private;
 struct drbd_md *md;
 enum drbd_uuid_index idx;

 if (!get_ldev_if_state(device, D_FAILED))
  return -ENODEV;

 md = &device->ldev->md;
 spin_lock_irq(&md->uuid_lock);
 for (idx = UI_CURRENT; idx <= UI_HISTORY_END; idx++) {
  seq_printf(m, "0x%016llX\n", md->uuid[idx]);
 }
 spin_unlock_irq(&md->uuid_lock);
 put_ldev(device);
 return 0;
}

static int device_ed_gen_id_show(struct seq_file *m, void *ignored)
{
 struct drbd_device *device = m->private;
 seq_printf(m, "0x%016llX\n", (unsigned long long)device->ed_uuid);
 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)
drbd_debugfs_device_attr(data_gen_id)
drbd_debugfs_device_attr(ed_gen_id)

void drbd_debugfs_device_add(struct drbd_device *device)
{
 struct dentry *vols_dir = device->resource->debugfs_res_volumes;
 char minor_buf[8]; /* MINORMASK, MINORBITS == 20; */
 char vnr_buf[8];   /* volume number vnr is even 16 bit only; */
 char *slink_name = NULL;

 struct dentry *dentry;
 if (!vols_dir || !drbd_debugfs_minors)
  return;

 snprintf(vnr_buf, sizeof(vnr_buf), "%u", device->vnr);
 dentry = debugfs_create_dir(vnr_buf, vols_dir);
 device->debugfs_vol = dentry;

 snprintf(minor_buf, sizeof(minor_buf), "%u", device->minor);
 slink_name = kasprintf(GFP_KERNEL, "../resources/%s/volumes/%u",
   device->resource->name, device->vnr);
 if (!slink_name)
  goto fail;
 dentry = debugfs_create_symlink(minor_buf, drbd_debugfs_minors, slink_name);
 device->debugfs_minor = dentry;
 kfree(slink_name);
 slink_name = NULL;

#define DCF(name) do {     \
 dentry = debugfs_create_file(#name, 0440, \
   device->debugfs_vol, device,  \
   &device_ ## name ## _fops);  \
 device->debugfs_vol_ ## name = dentry;   \
 } while (0)

 DCF(oldest_requests);
 DCF(act_log_extents);
 DCF(resync_extents);
 DCF(data_gen_id);
 DCF(ed_gen_id);
#undef DCF
 return;

fail:
 drbd_debugfs_device_cleanup(device);
 drbd_err(device, "failed to create debugfs entries\n");
}

void drbd_debugfs_device_cleanup(struct drbd_device *device)
{
 drbd_debugfs_remove(&device->debugfs_minor);
 drbd_debugfs_remove(&device->debugfs_vol_oldest_requests);
 drbd_debugfs_remove(&device->debugfs_vol_act_log_extents);
 drbd_debugfs_remove(&device->debugfs_vol_resync_extents);
 drbd_debugfs_remove(&device->debugfs_vol_data_gen_id);
 drbd_debugfs_remove(&device->debugfs_vol_ed_gen_id);
 drbd_debugfs_remove(&device->debugfs_vol);
}

void drbd_debugfs_peer_device_add(struct drbd_peer_device *peer_device)
{
 struct dentry *conn_dir = peer_device->connection->debugfs_conn;
 struct dentry *dentry;
 char vnr_buf[8];

 snprintf(vnr_buf, sizeof(vnr_buf), "%u", peer_device->device->vnr);
 dentry = debugfs_create_dir(vnr_buf, conn_dir);
 peer_device->debugfs_peer_dev = dentry;
}

void drbd_debugfs_peer_device_cleanup(struct drbd_peer_device *peer_device)
{
 drbd_debugfs_remove(&peer_device->debugfs_peer_dev);
}

static int drbd_version_show(struct seq_file *m, void *ignored)
{
 seq_printf(m, "# %s\n", drbd_buildtag());
 seq_printf(m, "VERSION=%s\n", REL_VERSION);
 seq_printf(m, "API_VERSION=%u\n", GENL_MAGIC_VERSION);
 seq_printf(m, "PRO_VERSION_MIN=%u\n", PRO_VERSION_MIN);
 seq_printf(m, "PRO_VERSION_MAX=%u\n", PRO_VERSION_MAX);
 return 0;
}

static int drbd_version_open(struct inode *inode, struct file *file)
{
 return single_open(file, drbd_version_show, NULL);
}

static const struct file_operations drbd_version_fops = {
 .owner = THIS_MODULE,
 .open = drbd_version_open,
 .llseek = seq_lseek,
 .read = seq_read,
 .release = single_release,
};

/* not __exit, may be indirectly called
 * from the module-load-failure path as well. */
void drbd_debugfs_cleanup(void)
{
 drbd_debugfs_remove(&drbd_debugfs_resources);
 drbd_debugfs_remove(&drbd_debugfs_minors);
 drbd_debugfs_remove(&drbd_debugfs_version);
 drbd_debugfs_remove(&drbd_debugfs_root);
}

void __init drbd_debugfs_init(void)
{
 struct dentry *dentry;

 dentry = debugfs_create_dir("drbd", NULL);
 drbd_debugfs_root = dentry;

 dentry = debugfs_create_file("version", 0444, drbd_debugfs_root, NULL, &drbd_version_fops);
 drbd_debugfs_version = dentry;

 dentry = debugfs_create_dir("resources", drbd_debugfs_root);
 drbd_debugfs_resources = dentry;

 dentry = debugfs_create_dir("minors", drbd_debugfs_root);
 drbd_debugfs_minors = dentry;
}