[DLM] more info through debugfs

Display more information from debugfs, particularly locks waiting for
a master lookup or operations waiting for a remote reply.

Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

3 files changed, 114 insertions, 24 deletions

diff --git a/fs/dlm/debug_fs.c b/fs/dlm/debug_fs.c
index 49deca845dba..5faa747c7ca1 100644
--- a/fs/dlm/debug_fs.c
+++ b/fs/dlm/debug_fs.c
@@ -18,6 +18,9 @@
 
 #include "dlm_internal.h"
 
+#define DLM_DEBUG_BUF_LEN 4096
+static char debug_buf[DLM_DEBUG_BUF_LEN];
+static struct mutex debug_buf_lock;
 
 static struct dentry *dlm_root;
 
@@ -28,6 +31,10 @@ struct rsb_iter {
         struct dlm_rsb *rsb;
 };
 
+/*
+ * dump all rsb's in the lockspace hash table
+ */
+
 static char *print_lockmode(int mode)
 {
         switch (mode) {
@@ -76,7 +83,7 @@ static void print_lock(struct seq_file *s, struct dlm_lkb *lkb,
 static int print_resource(struct dlm_rsb *res, struct seq_file *s)
 {
         struct dlm_lkb *lkb;
-        int i, lvblen = res->res_ls->ls_lvblen;
+        int i, lvblen = res->res_ls->ls_lvblen, recover_list, root_list;
 
         seq_printf(s, "\nResource %p Name (len=%d) \"", res, res->res_length);
         for (i = 0; i < res->res_length; i++) {
@@ -110,6 +117,15 @@ static int print_resource(struct dlm_rsb *res, struct seq_file *s)
                 seq_printf(s, "\n");
         }
 
+        root_list = !list_empty(&res->res_root_list);
+        recover_list = !list_empty(&res->res_recover_list);
+
+        if (root_list || recover_list) {
+                seq_printf(s, "Recovery: root %d recover %d flags %lx "
+                           "count %d\n", root_list, recover_list,
+                           res->flags, res->res_recover_locks_count);
+        }
+
         /* Print the locks attached to this resource */
         seq_printf(s, "Granted Queue\n");
         list_for_each_entry(lkb, &res->res_grantqueue, lkb_statequeue)
@@ -123,6 +139,18 @@ static int print_resource(struct dlm_rsb *res, struct seq_file *s)
         list_for_each_entry(lkb, &res->res_waitqueue, lkb_statequeue)
                 print_lock(s, lkb, res);
 
+        if (list_empty(&res->res_lookup))
+                goto out;
+
+        seq_printf(s, "Lookup Queue\n");
+        list_for_each_entry(lkb, &res->res_lookup, lkb_rsb_lookup) {
+                seq_printf(s, "%08x %s", lkb->lkb_id,
+                           print_lockmode(lkb->lkb_rqmode));
+                if (lkb->lkb_wait_type)
+                        seq_printf(s, " wait_type: %d", lkb->lkb_wait_type);
+                seq_printf(s, "\n");
+        }
+ out:
         return 0;
 }
 
@@ -190,7 +218,7 @@ static struct rsb_iter *rsb_iter_init(struct dlm_ls *ls)
         return ri;
 }
 
-static void *seq_start(struct seq_file *file, loff_t *pos)
+static void *rsb_seq_start(struct seq_file *file, loff_t *pos)
 {
         struct rsb_iter *ri;
         loff_t n = *pos;
@@ -209,7 +237,7 @@ static void *seq_start(struct seq_file *file, loff_t *pos)
         return ri;
 }
 
-static void *seq_next(struct seq_file *file, void *iter_ptr, loff_t *pos)
+static void *rsb_seq_next(struct seq_file *file, void *iter_ptr, loff_t *pos)
 {
         struct rsb_iter *ri = iter_ptr;
 
@@ -223,12 +251,12 @@ static void *seq_next(struct seq_file *file, void *iter_ptr, loff_t *pos)
         return ri;
 }
 
-static void seq_stop(struct seq_file *file, void *iter_ptr)
+static void rsb_seq_stop(struct seq_file *file, void *iter_ptr)
 {
         /* nothing for now */
 }
 
-static int seq_show(struct seq_file *file, void *iter_ptr)
+static int rsb_seq_show(struct seq_file *file, void *iter_ptr)
 {
         struct rsb_iter *ri = iter_ptr;
 
@@ -237,19 +265,19 @@ static int seq_show(struct seq_file *file, void *iter_ptr)
         return 0;
 }
 
-static struct seq_operations dlm_seq_ops = {
-        .start = seq_start,
-        .next  = seq_next,
-        .stop  = seq_stop,
-        .show  = seq_show,
+static struct seq_operations rsb_seq_ops = {
+        .start = rsb_seq_start,
+        .next  = rsb_seq_next,
+        .stop  = rsb_seq_stop,
+        .show  = rsb_seq_show,
 };
 
-static int do_open(struct inode *inode, struct file *file)
+static int rsb_open(struct inode *inode, struct file *file)
 {
         struct seq_file *seq;
         int ret;
 
-        ret = seq_open(file, &dlm_seq_ops);
+        ret = rsb_seq_open(file, &rsb_seq_ops);
         if (ret)
                 return ret;
 
@@ -259,32 +287,92 @@ static int do_open(struct inode *inode, struct file *file)
         return 0;
 }
 
-static struct file_operations dlm_fops = {
+static struct file_operations rsb_fops = {
         .owner   = THIS_MODULE,
-        .open    = do_open,
+        .open    = rsb_open,
         .read    = seq_read,
         .llseek  = seq_lseek,
         .release = seq_release
 };
 
+/*
+ * dump lkb's on the ls_waiters list
+ */
+
+static int waiters_open(struct inode *inode, struct file *file)
+{
+        file->private_data = inode->i_private;
+        return 0;
+}
+
+static ssize_t waiters_read(struct file *file, char __user *userbuf,
+                            size_t count, loff_t *ppos)
+{
+        struct dlm_ls *ls = file->private_data;
+        struct dlm_lkb *lkb;
+        size_t len = DLM_DEBUG_BUF_LEN, pos = 0, rv;
+
+        mutex_lock(&debug_buf_lock);
+        mutex_lock(&ls->ls_waiters_mutex);
+        memset(debug_buf, 0, sizeof(debug_buf));
+
+        list_for_each_entry(lkb, &ls->ls_waiters, lkb_wait_reply) {
+                pos += snprintf(debug_buf + pos, len - pos, "%x %d %d %s\n",
+                                lkb->lkb_id, lkb->lkb_wait_type,
+                                lkb->lkb_nodeid, lkb->lkb_resource->res_name);
+        }
+        mutex_unlock(&ls->ls_waiters_mutex);
+
+        rv = simple_read_from_buffer(userbuf, count, ppos, debug_buf, pos);
+        mutex_unlock(&debug_buf_lock);
+        return rv;
+}
+
+static struct file_operations waiters_fops = {
+        .owner   = THIS_MODULE,
+        .open    = waiters_open,
+        .read    = waiters_read
+};
+
 int dlm_create_debug_file(struct dlm_ls *ls)
 {
-        ls->ls_debug_dentry = debugfs_create_file(ls->ls_name,
-                                                  S_IFREG | S_IRUGO,
-                                                  dlm_root,
-                                                  ls,
-                                                  &dlm_fops);
-        return ls->ls_debug_dentry ? 0 : -ENOMEM;
+        char name[DLM_LOCKSPACE_LEN+8];
+
+        ls->ls_debug_rsb_dentry = debugfs_create_file(ls->ls_name,
+                                                      S_IFREG | S_IRUGO,
+                                                      dlm_root,
+                                                      ls,
+                                                      &rsb_fops);
+        if (!ls->ls_rsb_debug_dentry)
+                return -ENOMEM;
+
+        memset(name, 0, sizeof(name));
+        snprintf(name, DLM_LOCKSPACE_LEN+8, "%s_waiters", ls->ls_name);
+
+        ls->ls_debug_waiters_dentry = debugfs_create_file(name,
+                                                          S_IFREG | S_IRUGO,
+                                                          dlm_root,
+                                                          ls,
+                                                          &waiters_fops);
+        if (!ls->ls_debug_waiters_dentry) {
+                debugfs_remove(ls->ls_debug_rsb_dentry);
+                return -ENOMEM;
+        }
+
+        return 0;
 }
 
 void dlm_delete_debug_file(struct dlm_ls *ls)
 {
-        if (ls->ls_debug_dentry)
-                debugfs_remove(ls->ls_debug_dentry);
+        if (ls->ls_debug_rsb_dentry)
+                debugfs_remove(ls->ls_debug_rsb_dentry);
+        if (ls->ls_debug_waiters_dentry)
+                debugfs_remove(ls->ls_debug_waiters_dentry);
 }
 
 int dlm_register_debugfs(void)
 {
+        mutex_init(&debug_buf_lock);
         dlm_root = debugfs_create_dir("dlm", NULL);
         return dlm_root ? 0 : -ENOMEM;
 }
diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index db080de2a7e9..7c3c2d27c012 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -446,7 +446,8 @@ struct dlm_ls {
         struct dlm_lkb          ls_stub_lkb;    /* for returning errors */
         struct dlm_message      ls_stub_ms;     /* for faking a reply */
 
-        struct dentry           *ls_debug_dentry; /* debugfs */
+        struct dentry           *ls_debug_rsb_dentry; /* debugfs */
+        struct dentry           *ls_debug_waiters_dentry; /* debugfs */
 
         wait_queue_head_t       ls_uevent_wait; /* user part of join/leave */
         int                     ls_uevent_result;
diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c
index 3f6cb422ac4b..31ed0fe16a31 100644
--- a/fs/dlm/lockspace.c
+++ b/fs/dlm/lockspace.c
@@ -446,7 +446,8 @@ static int new_lockspace(char *name, int namelen, void **lockspace,
         memset(&ls->ls_stub_rsb, 0, sizeof(struct dlm_rsb));
         ls->ls_stub_rsb.res_ls = ls;
 
-        ls->ls_debug_dentry = NULL;
+        ls->ls_debug_rsb_dentry = NULL;
+        ls->ls_debug_waiters_dentry = NULL;
 
         init_waitqueue_head(&ls->ls_uevent_wait);
         ls->ls_uevent_result = 0;