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Date:      Tue, 1 Jul 2014 20:00:36 +0000 (UTC)
From:      Bryan Drewery <bdrewery@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r268114 - in head/sys: fs/nfsserver nfsserver
Message-ID:  <201407012000.s61K0aCO067439@svn.freebsd.org>

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Author: bdrewery
Date: Tue Jul  1 20:00:35 2014
New Revision: 268114
URL: http://svnweb.freebsd.org/changeset/base/268114

Log:
  Change NFS readdir() to only ignore cookies preceding the given offset for
  UFS rather than for all but ZFS.  This code was assuming that offsets were
  monotonically increasing for all file systems except ZFS and that the
  cookies from a previous call may have been rewound to a block boundary.
  According to mckusick@ only UFS is known to do this, so only requests against
  UFS file systems should remove cookies smaller than the given offset.  This
  fixes serving TMPFS over NFS as it too does not have monotonically increasing
  offsets.  The comment around the code also indicated it was specific to UFS.
  
  Some of the code using 'not_zfs' is specific to ZFS snapshot handling, so
  add a 'is_zfs' variable for those cases.
  
  It's possible that 'is_zfs' check for VFS_VGET() support may not be
  specific to ZFS.  This needs more research and testing.
  
  After this fix TMPFS and other file systems can be served over NFS.
  
  To test I compared the results of syncing a /usr/src tree into a tmpfs and
  serving that over NFS.  Before the fix 3589 files were missing on the remote
  view.  After the fix all files were successfully found.
  
  Reviewed by:	rmacklem
  Discussed with:	mckusick, rmacklem via fs@
  Discussed at:	http://lists.freebsd.org/pipermail/freebsd-fs/2014-April/019264.html
  MFC after:	2 weeks
  Sponsored by:	EMC / Isilon Storage Division

Modified:
  head/sys/fs/nfsserver/nfs_nfsdport.c
  head/sys/nfsserver/nfs_serv.c

Modified: head/sys/fs/nfsserver/nfs_nfsdport.c
==============================================================================
--- head/sys/fs/nfsserver/nfs_nfsdport.c	Tue Jul  1 19:50:47 2014	(r268113)
+++ head/sys/fs/nfsserver/nfs_nfsdport.c	Tue Jul  1 20:00:35 2014	(r268114)
@@ -1551,7 +1551,7 @@ nfsrvd_readdir(struct nfsrv_descript *nd
 	u_long *cookies = NULL, *cookiep;
 	struct uio io;
 	struct iovec iv;
-	int not_zfs;
+	int is_ufs;
 
 	if (nd->nd_repstat) {
 		nfsrv_postopattr(nd, getret, &at);
@@ -1606,7 +1606,7 @@ nfsrvd_readdir(struct nfsrv_descript *nd
 			nfsrv_postopattr(nd, getret, &at);
 		goto out;
 	}
-	not_zfs = strcmp(vp->v_mount->mnt_vfc->vfc_name, "zfs");
+	is_ufs = strcmp(vp->v_mount->mnt_vfc->vfc_name, "ufs") == 0;
 	MALLOC(rbuf, caddr_t, siz, M_TEMP, M_WAITOK);
 again:
 	eofflag = 0;
@@ -1686,12 +1686,10 @@ 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 ||
-	     (not_zfs != 0 && ((u_quad_t)(*cookiep)) <= toff))) {
+	     (is_ufs == 1 && ((u_quad_t)(*cookiep)) <= toff))) {
 		cpos += dp->d_reclen;
 		dp = (struct dirent *)cpos;
 		cookiep++;
@@ -1804,7 +1802,7 @@ nfsrvd_readdirplus(struct nfsrv_descript
 	struct uio io;
 	struct iovec iv;
 	struct componentname cn;
-	int at_root, needs_unbusy, not_zfs, supports_nfsv4acls;
+	int at_root, is_ufs, is_zfs, needs_unbusy, supports_nfsv4acls;
 	struct mount *mp, *new_mp;
 	uint64_t mounted_on_fileno;
 
@@ -1884,7 +1882,8 @@ nfsrvd_readdirplus(struct nfsrv_descript
 			nfsrv_postopattr(nd, getret, &at);
 		goto out;
 	}
-	not_zfs = strcmp(vp->v_mount->mnt_vfc->vfc_name, "zfs");
+	is_ufs = strcmp(vp->v_mount->mnt_vfc->vfc_name, "ufs") == 0;
+	is_zfs = strcmp(vp->v_mount->mnt_vfc->vfc_name, "zfs") == 0;
 
 	MALLOC(rbuf, caddr_t, siz, M_TEMP, M_WAITOK);
 again:
@@ -1957,12 +1956,10 @@ 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 ||
-	   (not_zfs != 0 && ((u_quad_t)(*cookiep)) <= toff) ||
+	   (is_ufs == 1 && ((u_quad_t)(*cookiep)) <= toff) ||
 	   ((nd->nd_flag & ND_NFSV4) &&
 	    ((dp->d_namlen == 1 && dp->d_name[0] == '.') ||
 	     (dp->d_namlen==2 && dp->d_name[0]=='.' && dp->d_name[1]=='.'))))) {
@@ -2004,7 +2001,7 @@ again:
 	 * This needs to be done here for NFSv4, since NFSv4 never does
 	 * a VFS_VGET() for "." or "..".
 	 */
-	if (not_zfs == 0) {
+	if (is_zfs == 1) {
 		r = VFS_VGET(mp, at.na_fileid, LK_SHARED, &nvp);
 		if (r == EOPNOTSUPP) {
 			usevget = 0;
@@ -2153,7 +2150,7 @@ again:
 					if (!r)
 					    r = nfsvno_getattr(nvp, nvap,
 						nd->nd_cred, p, 1);
-					if (r == 0 && not_zfs == 0 &&
+					if (r == 0 && is_zfs == 1 &&
 					    nfsrv_enable_crossmntpt != 0 &&
 					    (nd->nd_flag & ND_NFSV4) != 0 &&
 					    nvp->v_type == VDIR &&

Modified: head/sys/nfsserver/nfs_serv.c
==============================================================================
--- head/sys/nfsserver/nfs_serv.c	Tue Jul  1 19:50:47 2014	(r268113)
+++ head/sys/nfsserver/nfs_serv.c	Tue Jul  1 20:00:35 2014	(r268114)
@@ -2627,7 +2627,7 @@ nfsrv_readdir(struct nfsrv_descript *nfs
 	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 not_zfs;
+	int is_ufs;
 
 	nfsdbprintf(("%s %d\n", __FILE__, __LINE__));
 	fhp = &nfh.fh_generic;
@@ -2690,7 +2690,7 @@ nfsrv_readdir(struct nfsrv_descript *nfs
 		error = 0;
 		goto nfsmout;
 	}
-	not_zfs = strcmp(vp->v_mount->mnt_vfc->vfc_name, "zfs") != 0;
+	is_ufs = strcmp(vp->v_mount->mnt_vfc->vfc_name, "ufs") == 0;
 	VOP_UNLOCK(vp, 0);
 
 	/*
@@ -2777,12 +2777,10 @@ 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 ||
-		 (not_zfs != 0 && ((u_quad_t)(*cookiep)) <= toff))) {
+		 (is_ufs == 1 && ((u_quad_t)(*cookiep)) <= toff))) {
 		cpos += dp->d_reclen;
 		dp = (struct dirent *)cpos;
 		cookiep++;
@@ -2928,7 +2926,7 @@ nfsrv_readdirplus(struct nfsrv_descript 
 	int usevget = 1;
 	struct componentname cn;
 	struct mount *mntp = NULL;
-	int not_zfs;
+	int is_ufs;
 
 	nfsdbprintf(("%s %d\n", __FILE__, __LINE__));
 	vp_locked = 0;
@@ -2988,7 +2986,7 @@ nfsrv_readdirplus(struct nfsrv_descript 
 		error = 0;
 		goto nfsmout;
 	}
-	not_zfs = strcmp(vp->v_mount->mnt_vfc->vfc_name, "zfs") != 0;
+	is_ufs = strcmp(vp->v_mount->mnt_vfc->vfc_name, "ufs") == 0;
 	VOP_UNLOCK(vp, 0);
 	vp_locked = 0;
 	rbuf = malloc(siz, M_TEMP, M_WAITOK);
@@ -3068,12 +3066,10 @@ 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 ||
-		 (not_zfs != 0 && ((u_quad_t)(*cookiep)) <= toff))) {
+		 (is_ufs == 1 && ((u_quad_t)(*cookiep)) <= toff))) {
 		cpos += dp->d_reclen;
 		dp = (struct dirent *)cpos;
 		cookiep++;



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