Hi Adrian,
Since the util-linux mailing list seems to be dead, I wasn't sure where
to send this.
I've been working on an overhaul of the mount_nfs code for autofs. While
working on this, I've fixed the code that makes autofs prefer to mount
via addresses that are on the same subnet as the client machine.
Unfortunately, when we call mount with a hostname, it simply picks the
first address in the list, so even if we select a host on the same
subnet, we might end up mounting across a router anyway. I considered
just having autofs mount using the address, but when looking at a large
list of mounts, that can be harder for humans to read.
So, instead, I've rolled the attached patch for mount. This changes the
behavior of the 'addr=' option to be an address hint. If the address
passed via this option mounts any of the addresses resolved by
gethostbyname(), then we'll mount using that address. If it does not
match, then the current behavior prevails (we use the first address in
the list). I've done some basic testing on x86 and x86_64 and it seems
to work as expected.
I discussed this briefly on the CC'ed mailing lists here, and didn't get
any major objections. This patch is against util-linux-2.12q. Please let
me know if I should submit this for inclusion in util-linux in a
different way.
Thanks,
Jeff
Index: util-linux/mount/nfsmount.c
===================================================================
--- util-linux/mount/nfsmount.c (revision 170)
+++ util-linux/mount/nfsmount.c (working copy)
@@ -195,7 +195,7 @@
static char *prev_bg_host;
char hostdir[1024];
CLIENT *mclient;
- char *hostname, *dirname, *old_opts, *mounthost = NULL;
+ char *hostname, *dirname, *old_opts, *mounthost, *prefaddr_s = NULL;
char new_opts[1024];
struct timeval total_timeout;
enum clnt_stat clnt_stat;
@@ -207,6 +207,7 @@
struct sockaddr_in server_addr;
struct sockaddr_in mount_server_addr;
struct pmap *pm_mnt;
+ struct in_addr prefaddr;
int msock, fsock;
struct timeval retry_timeout;
union {
@@ -214,7 +215,7 @@
struct mountres3 nfsv3;
} status;
struct stat statbuf;
- char *s;
+ char *s = NULL;
int port, mountport, proto, bg, soft, intr;
int posix, nocto, noac, nolock, broken_suid;
int retry, tcp;
@@ -258,43 +259,6 @@
goto fail;
}
- server_addr.sin_family = AF_INET;
-#ifdef HAVE_inet_aton
- if (!inet_aton(hostname, &server_addr.sin_addr))
-#endif
- {
- if ((hp = gethostbyname(hostname)) == NULL) {
- fprintf(stderr, _("mount: can't get address for %s\n"),
- hostname);
- goto fail;
- } else {
- if (hp->h_length > sizeof(struct in_addr)) {
- fprintf(stderr,
- _("mount: got bad hp->h_length\n"));
- hp->h_length = sizeof(struct in_addr);
- }
- memcpy(&server_addr.sin_addr,
- hp->h_addr, hp->h_length);
- }
- }
-
- memcpy (&mount_server_addr, &server_addr, sizeof (mount_server_addr));
-
- /* add IP address to mtab options for use when unmounting */
-
- s = inet_ntoa(server_addr.sin_addr);
- old_opts = *extra_opts;
- if (!old_opts)
- old_opts = "";
- if (strlen(old_opts) + strlen(s) + 10 >= sizeof(new_opts)) {
- fprintf(stderr, _("mount: "
- "excessively long option argument\n"));
- goto fail;
- }
- sprintf(new_opts, "%s%saddr=%s",
- old_opts, *old_opts ? "," : "", s);
- *extra_opts = xstrdup(new_opts);
-
/* Set default options.
* rsize/wsize (and bsize, for ver >= 3) are left 0 in order to
* let the kernel decide.
@@ -328,6 +292,7 @@
nfsvers = 0;
/* parse options */
+ old_opts = xstrdup(*extra_opts);
for (opt = strtok(old_opts, ","); opt; opt = strtok(NULL, ",")) {
if ((opteq = strchr(opt, '='))) {
@@ -388,10 +353,10 @@
#endif
printf(_("Warning: Option namlen is not supported.\n"));
} else if (!strcmp(opt, "addr")) {
- /* ignore */;
+ prefaddr_s = opteq + 1;
} else {
printf(_("unknown nfs mount parameter: "
- "%s=%d\n"), opt, val);
+ "%s=%s\n"), opt, opteq+1);
goto fail;
}
} else {
@@ -477,8 +442,8 @@
data.rsize, data.wsize, data.timeo, data.retrans);
printf("acreg (min, max) = (%d, %d), acdir (min, max) = (%d, %d)\n",
data.acregmin, data.acregmax, data.acdirmin, data.acdirmax);
- printf("port = %d, bg = %d, retry = %d, flags = %.8x\n",
- port, bg, retry, data.flags);
+ printf("port = %d, bg = %d, retry = %d, flags = %.8x, addr = %s\n",
+ port, bg, retry, data.flags, prefaddr_s);
printf("mountprog = %d, mountvers = %d, nfsprog = %d, nfsvers = %d\n",
mountprog, mountvers, nfsprog, nfsvers);
printf("soft = %d, intr = %d, posix = %d, nocto = %d, noac = %d\n",
@@ -511,6 +476,78 @@
return retval;
}
+ s = NULL;
+ server_addr.sin_family = AF_INET;
+#ifdef HAVE_inet_aton
+ if (!inet_aton(hostname, &server_addr.sin_addr))
+#endif
+ {
+ if ((hp = gethostbyname(hostname)) == NULL) {
+ fprintf(stderr, _("mount: can't get address for %s\n"),
+ hostname);
+ goto fail;
+ } else {
+ if (hp->h_length > sizeof(struct in_addr)) {
+ fprintf(stderr,
+ _("mount: got bad hp->h_length\n"));
+ hp->h_length = sizeof(struct in_addr);
+ }
+
+ val = 0;
+ s = NULL;
+
+#ifdef HAVE_inet_aton
+ /* if a preferred address is specified, then make sure
+ * it matches one of the host's addresses before using
+ * it. If it doesn't, just use first host in list.
+ */
+ if (prefaddr_s) {
+ inet_aton(prefaddr_s,&prefaddr);
+ while(hp->h_addr_list[val]) {
+ if (prefaddr.s_addr == *(in_addr_t *)
+ (hp->h_addr_list[val])) {
+ s = hp->h_addr_list[val];
+ break;
+ }
+ ++val;
+ }
+
+ if (!s)
+ fprintf(stderr, _("mount: specified address doesn't match hostname. Ignoring it.\n"));
+ }
+#endif /* HAVE_inet_aton */
+
+ if (s) {
+ memcpy(&server_addr.sin_addr,
+ s, hp->h_length);
+ } else {
+ memcpy(&server_addr.sin_addr,
+ hp->h_addr, hp->h_length);
+ }
+ }
+ }
+
+ memcpy (&mount_server_addr, &server_addr, sizeof (mount_server_addr));
+
+ /* add IP address to mtab options for use when unmounting, if it
+ * wasn't specified or was ignored */
+ if (!s) {
+ s = inet_ntoa(server_addr.sin_addr);
+ old_opts = *extra_opts;
+
+ if (!old_opts)
+ old_opts = "";
+
+ if (strlen(old_opts) + strlen(s) + 10 >= sizeof(new_opts)) {
+ fprintf(stderr, _("mount: "
+ "excessively long option argument\n"));
+ goto fail;
+ }
+ sprintf(new_opts, "%s%saddr=%s",
+ old_opts, *old_opts ? "," : "", s);
+ *extra_opts = xstrdup(new_opts);
+ }
+
/* create mount deamon client */
/* See if the nfs host = mount host. */
if (mounthost) {
Index: util-linux/mount/mount.8
===================================================================
--- util-linux/mount/mount.8 (revision 170)
+++ util-linux/mount/mount.8 (working copy)
@@ -1317,7 +1317,10 @@
.BI namlen= n.
The option
.BI addr= n
-is accepted but ignored.
+acts as an address hint. If the address specified matches any of the addresses
+in the list returned by the gethostbyname() call, then the mount will use that
+address. If not specified or if it does not match, then the first address in
+the list is used (with a warning message if was specified and didn't match).
Also the following Boolean options, possibly preceded by
.B no
are recognized:
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