ZFS might not return monotonically increasing directory offset cookies,

so turn off UFS-specific hack that assumes so in ZFS case.
Before the change we can miss returning some directory entries to a
NFS client.

I believe that the hack should be moved to ufs_readdir(), but until we find
somebody who will do it, turn it off for ZFS in NFS server code.

Submitted by:	rmacklem
Discussed with:	rmacklem, mckusick
MFC after:	3 days

1 files changed, 10 insertions, 3 deletions

diff --git a/sys/nfsserver/nfs_serv.c b/sys/nfsserver/nfs_serv.c
index 1fd7047..eb14d12 100644
--- a/sys/nfsserver/nfs_serv.c
+++ b/sys/nfsserver/nfs_serv.c
@@ -2737,7 +2737,7 @@ nfsrv_readdir(struct nfsrv_descript *nfsd, struct nfssvc_sock *slp,
 	int v3 = (nfsd->nd_flag & ND_NFSV3);
 	u_quad_t off, toff, verf;
 	u_long *cookies = NULL, *cookiep; /* needs to be int64_t or off_t */
-	int vfslocked;
+	int vfslocked, not_zfs;
 
 	nfsdbprintf(("%s %d\n", __FILE__, __LINE__));
 	vfslocked = 0;
@@ -2801,6 +2801,7 @@ nfsrv_readdir(struct nfsrv_descript *nfsd, struct nfssvc_sock *slp,
 		error = 0;
 		goto nfsmout;
 	}
+	not_zfs = strcmp(vp->v_mount->mnt_vfc->vfc_name, "zfs") != 0;
 	VOP_UNLOCK(vp, 0);
 
 	/*
@@ -2887,10 +2888,12 @@ again:
 	 * skip over the records that precede the requested offset. This
 	 * requires the assumption that file offset cookies monotonically
 	 * increase.
+	 * Since the offset cookies don't monotonically increase for ZFS,
+	 * this is not done when ZFS is the file system.
 	 */
 	while (cpos < cend && ncookies > 0 &&
 		(dp->d_fileno == 0 || dp->d_type == DT_WHT ||
-		 ((u_quad_t)(*cookiep)) <= toff)) {
+		 (not_zfs != 0 && ((u_quad_t)(*cookiep)) <= toff))) {
 		cpos += dp->d_reclen;
 		dp = (struct dirent *)cpos;
 		cookiep++;
@@ -3037,6 +3040,7 @@ nfsrv_readdirplus(struct nfsrv_descript *nfsd, struct nfssvc_sock *slp,
 	int usevget = 1, vfslocked;
 	struct componentname cn;
 	struct mount *mntp = NULL;
+	int not_zfs;
 
 	nfsdbprintf(("%s %d\n", __FILE__, __LINE__));
 	vfslocked = 0;
@@ -3097,6 +3101,7 @@ nfsrv_readdirplus(struct nfsrv_descript *nfsd, struct nfssvc_sock *slp,
 		error = 0;
 		goto nfsmout;
 	}
+	not_zfs = strcmp(vp->v_mount->mnt_vfc->vfc_name, "zfs") != 0;
 	VOP_UNLOCK(vp, 0);
 	vp_locked = 0;
 	rbuf = malloc(siz, M_TEMP, M_WAITOK);
@@ -3176,10 +3181,12 @@ again:
 	 * skip over the records that precede the requested offset. This
 	 * requires the assumption that file offset cookies monotonically
 	 * increase.
+	 * Since the offset cookies don't monotonically increase for ZFS,
+	 * this is not done when ZFS is the file system.
 	 */
 	while (cpos < cend && ncookies > 0 &&
 		(dp->d_fileno == 0 || dp->d_type == DT_WHT ||
-		 ((u_quad_t)(*cookiep)) <= toff)) {
+		 (not_zfs != 0 && ((u_quad_t)(*cookiep)) <= toff))) {
 		cpos += dp->d_reclen;
 		dp = (struct dirent *)cpos;
 		cookiep++;