> On 17 May 2017, at 19:21, Luis Henriques <[email protected]> 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: [email protected] > Link: http://tracker.ceph.com/issues/19958 > Signed-off-by: Luis Henriques <[email protected]> > --- > 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 Regards Yan, Zheng > > return d_obtain_alias(inode);
