> On 19 May 2017, at 00:48, Luis Henriques <lhenriq...@suse.com> wrote: > > 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?
Applied. Thanks Yan, Zheng > > Cheers, > -- > Luís
