[GFS2] lockdump improvements

The patch below consists of the following changes (in code order):

1. I fixed a minor compiler warning regarding the printing of
   a kernel symbol address.
2. I implemented a suggestion from Dave Teigland that moves
   the debugfs information for gfs2 into a subdirectory so
   we can easily expand our use of debugfs in the future.
   The current code keeps the glock information in:
   /debug/gfs2/<fs>
   With the patch, the new code keeps the glock information in:
   /debug/gfs2/<fs>/glock
   That will allow us to create more debugfs files in the future.
3. This fixes a bug whereby a failed mount attempt causes the
   debugfs file to not be deleted.  Failed mount attempts should
   always clean up after themselves, including deleting the
   debugfs file and/or directory.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

3 files changed, 21 insertions, 9 deletions

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index b075f9359c60..7988715b7a07 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -1774,7 +1774,7 @@ static void gfs2_print_symbol(struct glock_iter *gi, const char *fmt,
 
         if (gi) {
                 memset(buffer, 0, sizeof(buffer));
-                sprintf(buffer, "%p", address);
+                sprintf(buffer, "0x%08lx", address);
                 print_dbg(gi, fmt, buffer);
         }
         else
@@ -2146,11 +2146,14 @@ static const struct file_operations gfs2_debug_fops = {
 
 int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
 {
-        sdp->debugfs_dentry = debugfs_create_file(sdp->sd_table_name,
-                                                  S_IFREG | S_IRUGO,
-                                                  gfs2_root, sdp,
-                                                  &gfs2_debug_fops);
-        if (!sdp->debugfs_dentry)
+        sdp->debugfs_dir = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
+        if (!sdp->debugfs_dir)
+                return -ENOMEM;
+        sdp->debugfs_dentry_glocks = debugfs_create_file("glocks",
+                                                         S_IFREG | S_IRUGO,
+                                                         sdp->debugfs_dir, sdp,
+                                                         &gfs2_debug_fops);
+        if (!sdp->debugfs_dentry_glocks)
                 return -ENOMEM;
 
         return 0;
@@ -2158,8 +2161,14 @@ int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
 
 void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
 {
-        if (sdp && sdp->debugfs_dentry)
-                debugfs_remove(sdp->debugfs_dentry);
+        if (sdp && sdp->debugfs_dir) {
+                if (sdp->debugfs_dentry_glocks) {
+                        debugfs_remove(sdp->debugfs_dentry_glocks);
+                        sdp->debugfs_dentry_glocks = NULL;
+                }
+                debugfs_remove(sdp->debugfs_dir);
+                sdp->debugfs_dir = NULL;
+        }
 }
 
 int gfs2_register_debugfs(void)
@@ -2171,4 +2180,5 @@ int gfs2_register_debugfs(void)
 void gfs2_unregister_debugfs(void)
 {
         debugfs_remove(gfs2_root);
+        gfs2_root = NULL;
 }
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index fdf04705906f..d995441373ab 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -609,7 +609,8 @@ struct gfs2_sbd {
 
         unsigned long sd_last_warning;
         struct vfsmount *sd_gfs2mnt;
-        struct dentry *debugfs_dentry; /* for debugfs */
+        struct dentry *debugfs_dir;    /* debugfs directory */
+        struct dentry *debugfs_dentry_glocks; /* for debugfs */
 };
 
 #endif /* __INCORE_DOT_H__ */
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index ecb8b18de0ee..2c5f8e7def0d 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -756,6 +756,7 @@ fail_lm:
 fail_sys:
         gfs2_sys_fs_del(sdp);
 fail:
+        gfs2_delete_debugfs_file(sdp);
         kfree(sdp);
         sb->s_fs_info = NULL;
         return error;