Hello, On executing "blktrace -k" on a running trace, the trace hangs. After killing the trace, rerunning it results in "BLKTRACESTOP: invalid argument" messages. This was discussed earlier here: http://www.mail-archive.com/linux-btrace@xxxxxxxxxxxxxxx/msg00229.html But I dont see this fix to have been included as I'm still seeing this error with the the latest kernel. Could someone please indicate why this fix didnt go in? I was able to port the above suggested fix to 2.6.28. diff -Nuarp a/block/blktrace.c b/block/blktrace.c --- a/block/blktrace.c 2008-12-24 17:26:37.000000000 -0600 +++ b/block/blktrace.c 2009-01-02 11:13:11.000000000 -0600 @@ -181,59 +181,12 @@ EXPORT_SYMBOL_GPL(__blk_add_trace); 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); @@ -336,7 +289,18 @@ static int blk_subbuf_start_callback(str 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; } @@ -394,7 +358,15 @@ int do_blk_trace_setup(struct request_qu 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; @@ -437,8 +409,6 @@ int do_blk_trace_setup(struct request_qu return 0; err: - if (dir) - blk_remove_tree(dir); if (bt) { if (bt->msg_file) debugfs_remove(bt->msg_file); Vinay Sridhar, Linux Technology Center, IBM ISTL, Bangalore, India -- To unsubscribe from this list: send the line "unsubscribe linux-btrace" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
