Messages in this thread | | | Date | Sun, 25 Jan 2015 19:59:32 +0000 | From | Al Viro <> | Subject | Re: [PATCH 3/5 v2] tracing: Automatically mount tracefs on debugfs/tracing |
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On Sun, Jan 25, 2015 at 02:38:30PM -0500, Steven Rostedt wrote: > On Sun, 25 Jan 2015 21:22:07 +0800 > Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > > > > If we could do it in a non-racy way, that would be good, otherwise I > > don't see us being able to even take this patch :( > > Is it still racy even if it's only done at boot up? This path only gets > hit the first time it is called. "if (tr->flags &TRACE_ARRAY_FL_GLOBAL)" > is the top level tracing directory ("tracing") and is only called > during boot up (fs_initcall) and never hit again. I could even make > this called directly by that code so we could label it "__init" to make > sure that it is to be never hit. Or is this racy even when done by > fs_initcall? > > Waiting for Al to comment on this, because, I can't add this feature > until debugfs/tracing still containing the tracing information, > otherwise it will break all the tools that interact with the tracing > infrastructure, and we all know how happy Linus feels about such > changes.
Actually, I'm almost done massaging that sucker into adding debugfs_create_automount(). The only remaining question is what arguments do we put it; for now I'm giving it dentry_operations + data (to go into inode->i_private), but it might be better to give it a pointer just to d_automount() callback + data for it...
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