Commit cd156549 authored Apr 10, 2006 by NeilBrown Committed by Linus Torvalds Apr 11, 2006

[PATCH] knfsd: nfsd: oops exporting nonexistent directory



Export a directory that does not exist:
	exportfs -orw,fsid=0,insecure,no_subtree_check client:/home/NFS4

Try to mount from client with nfs4. Mount hangs (I'm not sure why -
that's another issue).

While client is hung, back on server

	mkdir /home/NFS4

The server panics in dput.  I traced the problem back to svc_export_parse()
calling path_release() even though path_lookup() failed (it happens to fill in
the nameidata structure with a negative dentry - so the test after out:
succeeds).

After patching, an recreating the problem, the client mount still takes some
time before finally exiting with a message "couldn't read superblock".

Here is a simple patch to resolve this issue:

Signed-off-by: Frank Filz <ffilzlnx@us.ibm.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent b5872b0d

fs/nfsd/export.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -422,7 +422,7 @@ static int svc_export_parse(struct cache_detail cd, char mesg, int mlen)
		if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
		goto out;
		err = path_lookup(buf, 0, &nd);
		if (err) goto out;
		if (err) goto out_no_path;

		exp.h.flags = 0;
		exp.ex_client = dom;
		@@ -475,6 +475,7 @@ static int svc_export_parse(struct cache_detail cd, char mesg, int mlen)
		out:
		if (nd.dentry)
		path_release(&nd);
		out_no_path:
		if (dom)
		auth_domain_put(dom);
		kfree(buf);

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