On Thu, May 18, 2017 at 09:36:44PM +0800, Yan, Zheng wrote: > > > On 17 May 2017, at 19:21, Luis Henriques <lhenriq...@suse.com> wrote: > > > > Converting a file handle to a dentry can be done call after the inode > > unlink. This means that __fh_to_dentry() requires an extra check to > > verify the number of links is not 0. > > > > The issue can be easily reproduced using xfstest generic/426, which does > > something like: > > > > name_to_handle_at(&fh) > > echo 3 > /proc/sys/vm/drop_caches > > unlink() > > open_by_handle_at(&fh) > > > > The call to open_by_handle_at() should fail, as the file doesn't exist > > anymore. > > > > Cc: sta...@vger.kernel.org > > Link: http://tracker.ceph.com/issues/19958 > > Signed-off-by: Luis Henriques <lhenriq...@suse.com> > > --- > > fs/ceph/export.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/fs/ceph/export.c b/fs/ceph/export.c > > index e8f11fa565c5..7df550c13d7f 100644 > > --- a/fs/ceph/export.c > > +++ b/fs/ceph/export.c > > @@ -91,6 +91,10 @@ static struct dentry *__fh_to_dentry(struct super_block > > *sb, u64 ino) > > ceph_mdsc_put_request(req); > > if (!inode) > > return ERR_PTR(-ESTALE); > > + if (inode->i_nlink == 0) { > > + iput(inode); > > + return ERR_PTR(-ESTALE); > > + } > > } > > maybe we should do this check in MDS
Thank you for your review. Are you suggesting to do this check *only* in the MDS? I guess that's probably a good thing to do too, but don't you think it's a good idea to keep it on the client side as well? Cheers, -- Luís
