From de8fd61f8e692d5d8207d7c30e8914da05ca122f Mon Sep 17 00:00:00 2001 From: neilbrown Date: Thu, 17 Jan 2002 00:03:48 +0000 Subject: [PATCH] See Changelog --- ChangeLog | 13 +++++++++++++ support/nfs/exports.c | 33 ++++++++++++++++++++++++--------- utils/exportfs/exports.man | 32 +++++++++++++++++++++++--------- 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 + NeilBrown + + * 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 * 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 ⅇ } @@ -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 -- 2.39.2