See Changelog

3 files changed, 60 insertions, 18 deletions

diff --git a/ChangeLog b/ChangeLog
index 59276dd..93d5ab8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2002-01-17   Adrian Drzewiecki <drze@MissionCriticalLinux.com>
+	     NeilBrown <neilb@cse.unsw.edu.au>
+
+	* support/nfs/exports.c: remove NFSEXP_ASYNC as a default
+	flag so that "sync" becomes the default.
+	Check that either "sync" or "async" is given as an option
+	and warn if neither are present
+	* utils/exportfs/exports.man: change documentation for "sync"
+	to be documentation for "async".
+	* utils/exportfs/exportfs.man: note that "sync" is the default
+	rather than "async"
+	
+	
 2002-01-02  Chip Salzenberg  <chip@pobox.com>
 
 	* support/export/nfsctl.c (expsetup): Don't export entries that
diff --git a/support/nfs/exports.c b/support/nfs/exports.c
index 7e0decf..0dce25f 100644
--- a/support/nfs/exports.c
+++ b/support/nfs/exports.c
@@ -29,7 +29,7 @@
 #include "xio.h"
 
 #define EXPORT_DEFAULT_FLAGS	\
-  (NFSEXP_ASYNC|NFSEXP_READONLY|NFSEXP_ROOTSQUASH|NFSEXP_GATHERED_WRITES)
+  (NFSEXP_READONLY|NFSEXP_ROOTSQUASH|NFSEXP_GATHERED_WRITES)
 
 static char	*efname = NULL;
 static XFILE	*efp = NULL;
@@ -117,10 +117,8 @@ getexportent(int fromkernel)
 			return NULL;
 		}
 		*sp = '\0';
-		if (parseopts(opt, &ee) < 0)
-			return NULL;
 	} else {
-	    xlog(L_WARNING, "No options for %s %s: suggest %s() to avoid warning", ee.e_path, exp, exp);
+	    xlog(L_WARNING, "No options for %s %s: suggest %s(sync) to avoid warning", ee.e_path, exp, exp);
 	}
 	if (strlen(exp) >= sizeof(ee.e_hostname)) {
 		syntaxerr("client name too long");
@@ -129,6 +127,9 @@ getexportent(int fromkernel)
 	strncpy(ee.e_hostname, exp, sizeof (ee.e_hostname) - 1);
 	ee.e_hostname[sizeof (ee.e_hostname) - 1] = '\0';
 
+	if (parseopts(opt, &ee) < 0)
+		return NULL;
+
 	/* resolve symlinks */
 	if (realpath(ee.e_path, rpath) != NULL) {
 		rpath[sizeof (rpath) - 1] = '\0';
@@ -266,7 +267,7 @@ mkexportent(char *hname, char *path, char *options)
 	ee.e_path[sizeof (ee.e_path) - 1] = '\0';
 	strncpy (ee.m_path, ee.e_path, sizeof (ee.m_path) - 1);
 	ee.m_path [sizeof (ee.m_path) - 1] = '\0';
-	if (options && parseopts(options, &ee) < 0)
+	if (parseopts(options, &ee) < 0)
 		return NULL;
 	return &ee;
 }
@@ -274,7 +275,7 @@ mkexportent(char *hname, char *path, char *options)
 int
 updateexportent(struct exportent *eep, char *options)
 {
-	if (options && parseopts(options, eep) < 0)
+	if (parseopts(options, eep) < 0)
 		return 0;
 	return 1;
 }
@@ -285,12 +286,17 @@ updateexportent(struct exportent *eep, char *options)
 static int
 parseopts(char *cp, struct exportent *ep)
 {
+	int	had_sync_opt = 0;
 
 	squids = ep->e_squids; nsquids = ep->e_nsquids;
 	sqgids = ep->e_sqgids; nsqgids = ep->e_nsqgids;
 
+	if (!cp)
+		goto out;
+
 	while (isblank(*cp))
 		cp++;
+
 	while (*cp) {
 		char *opt = strdup(cp);
 		char *optstart = cp;
@@ -310,11 +316,13 @@ parseopts(char *cp, struct exportent *ep)
 			ep->e_flags &= ~NFSEXP_INSECURE_PORT;
 		else if (!strcmp(opt, "insecure"))
 			ep->e_flags |= NFSEXP_INSECURE_PORT;
-		else if (!strcmp(opt, "sync"))
+		else if (!strcmp(opt, "sync")) {
+			had_sync_opt = 1;
 			ep->e_flags &= ~NFSEXP_ASYNC;
-		else if (!strcmp(opt, "async"))
+		} else if (!strcmp(opt, "async")) {
+			had_sync_opt = 1;
 			ep->e_flags |= NFSEXP_ASYNC;
-		else if (!strcmp(opt, "nohide"))
+		} else if (!strcmp(opt, "nohide"))
 			ep->e_flags |= NFSEXP_CROSSMNT;
 		else if (!strcmp(opt, "hide"))
 			ep->e_flags &= ~NFSEXP_CROSSMNT;
@@ -383,6 +391,13 @@ parseopts(char *cp, struct exportent *ep)
 	ep->e_nsquids = nsquids;
 	ep->e_nsqgids = nsqgids;
 
+out:
+	if (!had_sync_opt)
+		xlog(L_WARNING, "No 'sync' or 'async' option specified for export \"%s:%s\".\n"
+				"  Assuming default behaviour ('sync').\n"
+		     		"  NOTE: this default has changed from previous versions\n",
+				ep->e_hostname, ep->e_path);
+
 	return 1;
 }
 
diff --git a/utils/exportfs/exports.man b/utils/exportfs/exports.man
index 5dcc809..97264cd 100644
--- a/utils/exportfs/exports.man
+++ b/utils/exportfs/exports.man
@@ -95,17 +95,31 @@ This can also be made explicit by using
 the
 .IR ro " option.
 .TP
-.IR sync
-This option requests that all file writes be committed to disc before
-the write request completes.  This is required for complete safety of
-data in the face of a server crash, but incurs a performance hit.
-The default is to allow the server to write the data out whenever it
-is ready.  This can be explicitly requested with the
-.IR async " option.
+.IR async
+This option allows the NFS server to violate the NFS protocol and
+reply to requests before any changes made by that request have been
+committed to stable storage (e.g. disc drive).
+
+Using this option usually improves performance, but at the cost that
+an unclean server restart (i.e. a crash) can cause data to be lost or
+corrupted.
+
+In releases of nfs-utils upto and including 1.0.0, this option was the
+default.  In this and future releases,
+.I sync
+is the default, and
+.I async
+must be explicit requested if needed.
+To help make system adminstrators aware of this change, 'exportfs'
+will issue a warning if neither
+.I sync
+nor
+.I async
+is specified.
 .TP
 .IR no_wdelay
-This option only has effect if
-.I sync
+This option has no effect if
+.I async
 is also set.  The NFS server will normally delay committing a write request
 to disc slightly if it suspects that another related write request may be in
 progress or may arrive soon.  This allows multiple write requests to