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Commit f48fc4d3 authored by Jens Axboe's avatar Jens Axboe
Browse files

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: default avatarJens Axboe <jens.axboe@oracle.com>
parent 32231638

block/blktrace.c

+21 −51
Original line number Diff line number Diff line
@@ -187,59 +187,12 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 


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_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, 


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 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 
		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 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 
	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);