From: Al Viro <viro@ZenIV.linux.org.uk>
To: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: linux-fsdevel@vger.kernel.org
Subject: [heads-up] mknod() broken on nfs4
Date: Wed, 22 Jun 2011 00:59:00 +0100 [thread overview]
Message-ID: <20110621235900.GB11521@ZenIV.linux.org.uk> (raw)
Try mknod(path, 0777, 0); with path leading into nfs4. It
leads to call of nfs_open_create(), with nd->intent.open.file being
uninitialized. Note that LOOKUP_CREATE is set and so's LOOKUP_EXCL,
but LOOKUP_OPEN isn't. So nfs_atomic_lookup() falls through to
nfs_lookup(), which sees that we are doing exclusive create and just
does d_instantiate(dentry, NULL) and do nothing else. And then
we hit ->create()...
Results are ugly - random errors (often -EINVAL or -ENOENT)
and possibility of memory corruption if we manage to generate a request
that won't fail on server.
The really interesting question is what should we pass in
NFS_PROTO(dir)->create() in open_flags. I suspect that you are
checking the wrong flag there (LOOKUP_CREATE instead of LOOKUP_OPEN),
but I'm not sure what *should* be passed when LOOKUP_OPEN is not
there...
next reply other threads:[~2011-06-21 23:59 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-21 23:59 Al Viro [this message]
2011-06-22 0:23 ` [heads-up] mknod() broken on nfs4 Al Viro
[not found] ` <20110622002359.GC11521-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2011-06-22 23:00 ` Trond Myklebust
[not found] ` <1308783620.25875.30.camel-SyLVLa/KEI9HwK5hSS5vWB2eb7JE58TQ@public.gmane.org>
2011-06-22 23:19 ` Al Viro
2011-06-23 2:48 ` Al Viro
2011-06-23 5:37 ` Al Viro
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