Re: [PATCH 1/2] vfs: make fcheck_files() an exported functions

[Al Viro <viro@ZenIV.linux.org.uk>]

On Sat, Feb 09, 2013 at 11:24:47AM -0800, Tejun Heo wrote:
> (cc'ing Andrew)
> 
> On Wed, Jan 09, 2013 at 09:01:05AM -0800, Tejun Heo wrote:
> > We want to add a trace point to fcheck_files() but macros and inline
> > functions defined in header files can't have tracing points.  Move
> > fcheck_files() to fs/file.c and make it a proper function.
> > 
> > A lot of high-frequency fcheck*() users are inside fs/file.c, and, to
> > reduce the effect of this change, the new exported function is also
> > declared inline.
> > 
> > Signed-off-by: Tejun Heo <tj@kernel.org>
> > Cc: Steven Rostedt <rostedt@goodmis.org>
> > Cc: Al Viro <viro@zeniv.linux.org.uk>
> > ---
> > These two patches add vfs_fcheck tracepoint.  Making fcheck_files() a
> > function isn't optimal but given the tracepoint restriction I can't
> > think of a better way.  The TP is currently in use in google to allow
> > ioblame to track who's accessing which file which in turn is used to
> > approximately associate IOs with files.  I'm working to upstream the
> > rest of ioblame.
> 
> Andrew, can you please pick up these two patches?  They were posted a
> month ago and at least nobody seems violently against them.  The
> original patches are,

Consider *any* tracepoints in that area blanketly NAKed.  Sorry, I thought
I made it clear, but just in case:

As far as I'm concerned, *the* *only* interface stability warranties in VFS
are those for syscalls.  Which means that no tracepoints are going to be
acceptable there.  End of story.