block: get rid of the manual directory counting in blktrace
It can result in a stuck blktrace system, if --kill is used.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/blktrace.c b/block/blktrace.c
index b0a2cae..39cc3bf 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -187,59 +187,12 @@
static struct dentry *blk_tree_root;
static DEFINE_MUTEX(blk_tree_mutex);
-static unsigned int root_users;
-
-static inline void blk_remove_root(void)
-{
- if (blk_tree_root) {
- debugfs_remove(blk_tree_root);
- blk_tree_root = NULL;
- }
-}
-
-static void blk_remove_tree(struct dentry *dir)
-{
- mutex_lock(&blk_tree_mutex);
- debugfs_remove(dir);
- if (--root_users == 0)
- blk_remove_root();
- mutex_unlock(&blk_tree_mutex);
-}
-
-static struct dentry *blk_create_tree(const char *blk_name)
-{
- struct dentry *dir = NULL;
- int created = 0;
-
- mutex_lock(&blk_tree_mutex);
-
- if (!blk_tree_root) {
- blk_tree_root = debugfs_create_dir("block", NULL);
- if (!blk_tree_root)
- goto err;
- created = 1;
- }
-
- dir = debugfs_create_dir(blk_name, blk_tree_root);
- if (dir)
- root_users++;
- else {
- /* Delete root only if we created it */
- if (created)
- blk_remove_root();
- }
-
-err:
- mutex_unlock(&blk_tree_mutex);
- return dir;
-}
static void blk_trace_cleanup(struct blk_trace *bt)
{
- relay_close(bt->rchan);
debugfs_remove(bt->msg_file);
debugfs_remove(bt->dropped_file);
- blk_remove_tree(bt->dir);
+ relay_close(bt->rchan);
free_percpu(bt->sequence);
free_percpu(bt->msg_data);
kfree(bt);
@@ -346,7 +299,18 @@
static int blk_remove_buf_file_callback(struct dentry *dentry)
{
+ struct dentry *parent = dentry->d_parent;
debugfs_remove(dentry);
+
+ /*
+ * this will fail for all but the last file, but that is ok. what we
+ * care about is the top level buts->name directory going away, when
+ * the last trace file is gone. Then we don't have to rmdir() that
+ * manually on trace stop, so it nicely solves the issue with
+ * force killing of running traces.
+ */
+
+ debugfs_remove(parent);
return 0;
}
@@ -404,7 +368,15 @@
goto err;
ret = -ENOENT;
- dir = blk_create_tree(buts->name);
+
+ if (!blk_tree_root) {
+ blk_tree_root = debugfs_create_dir("block", NULL);
+ if (!blk_tree_root)
+ return -ENOMEM;
+ }
+
+ dir = debugfs_create_dir(buts->name, blk_tree_root);
+
if (!dir)
goto err;
@@ -458,8 +430,6 @@
atomic_dec(&blk_probes_ref);
mutex_unlock(&blk_probe_mutex);
err:
- if (dir)
- blk_remove_tree(dir);
if (bt) {
if (bt->msg_file)
debugfs_remove(bt->msg_file);