Commit afdb63f4 authored by Jeff Layton's avatar Jeff Layton Committed by zhaoxiaoqiang11
Browse files

nfsd: fix handling of readdir in v4root vs. mount upcall timeout 

stable inclusion
from stable-v5.10.163
commit d0c46b55d6d9962f532a0fd8af38272e5ce15927
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7PJ9N

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d0c46b55d6d9962f532a0fd8af38272e5ce15927

----------------------------------------------------

commit cad85337 upstream.

If v4 READDIR operation hits a mountpoint and gets back an error,
then it will include that entry in the reply and set RDATTR_ERROR for it
to the error.

That's fine for "normal" exported filesystems, but on the v4root, we
need to be more careful to only expose the existence of dentries that
lead to exports.

If the mountd upcall times out while checking to see whether a
mountpoint on the v4root is exported, then we have no recourse other
than to fail the whole operation.

Cc: Steve Dickson <steved@redhat.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216777


Reported-by: default avatarJianHong Yin <yin-jianhong@163.com>
Signed-off-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarzhaoxiaoqiang11 <zhaoxiaoqiang11@jd.com>
parent 36637a22

fs/nfsd/nfs4xdr.c

+11 −0
Original line number Diff line number Diff line
@@ -3405,6 +3405,17 @@ nfsd4_encode_dirent(void *ccdv, const char *name, int namlen, 
	case nfserr_noent:

		xdr_truncate_encode(xdr, start_offset);

		goto skip_entry;

	case nfserr_jukebox:

		/*

		 * The pseudoroot should only display dentries that lead to

		 * exports. If we get EJUKEBOX here, then we can't tell whether

		 * this entry should be included. Just fail the whole READDIR

		 * with NFS4ERR_DELAY in that case, and hope that the situation

		 * will resolve itself by the client's next attempt.

		 */

		if (cd->rd_fhp->fh_export->ex_flags & NFSEXP_V4ROOT)

			goto fail;

		fallthrough;

	default:

		/*

		 * If the client requested the RDATTR_ERROR attribute,