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Commit bb20c18d authored by Nick Piggin's avatar Nick Piggin Committed by Nick Piggin
Browse files

fs: force_reval_path drop rcu-walk before d_invalidate 



d_revalidate can return in rcu-walk mode even when it returns 0.  We can't just
call any old dcache function on rcu-walk dentry (the dentry is unstable, so
even through d_lock can safely be taken, the result may no longer be what we
expect -- careful re-checks would be required). So just drop rcu in this case.

(I missed this conversion when switching to the rcu-walk convention that Linus
suggested)

Signed-off-by: default avatarNick Piggin <npiggin@kernel.dk>
parent a82416da

fs/namei.c

+10 −0
Original line number Diff line number Diff line
@@ -583,6 +583,13 @@ void release_open_intent(struct nameidata *nd) 
		fput(nd->intent.open.file);

}



/*

 * Call d_revalidate and handle filesystems that request rcu-walk

 * to be dropped. This may be called and return in rcu-walk mode,

 * regardless of success or error. If -ECHILD is returned, the caller

 * must return -ECHILD back up the path walk stack so path walk may

 * be restarted in ref-walk mode.

 */

static int d_revalidate(struct dentry *dentry, struct nameidata *nd)

{

	int status;
@@ -673,6 +680,9 @@ force_reval_path(struct path *path, struct nameidata *nd) 
		return 0;



	if (!status) {

		/* Don't d_invalidate in rcu-walk mode */

		if (nameidata_drop_rcu(nd))

			return -ECHILD;

		d_invalidate(dentry);

		status = -ESTALE;

	}