Rewrite of nfs.c to keep options per host separated. #2790

FransUrbo · 2014-10-11T10:56:30Z

Example: Setting sharenfs to

  "rw=@192.168.69.8,no_subtree_check,no_root_squash,ro=@192.168.69.45,no_subtree_check,root_squash"

will create the option string

  sec=sys,ro,no_subtree_check,no_root_squash,mountpoint,no_subtree_check,no_root_squash,no_subtree_check,root_squash

which is then run on each host!. Part of this is "default" options.

Instead, go through the option string, look for hosts and then make sure options for each host is kept apart by using a linked list (maintained by the ZFS list_* functions).
Also, the default options should only be added to the list of options if setting sharenfs to on.

Closes: #2773

The text was updated successfully, but these errors were encountered:

behlendorf · 2014-10-23T00:12:18Z

Attempting to translate the Solaris syntax is really becoming a pain. While looking at this I noticed that the FreeBSD implementation doesn't even try, they require FreeBSD style options. So in some sense we've already lost the battle since by translating we're going to be at best compatibility with Illumos. We may want to reconsider this policy.

Leaving that matter aside this patch doesn't look quite right to me. It does address the case in #2773 but it appears to break other cases which end users may be depending on. For example, the updated code doesn't appear to allow you to list multiple colon seperated hosts. For example, rw=192.168.1.1:192.168.1.2. Plus it appears to break the duplicate detection code.

FransUrbo · 2014-10-24T13:51:23Z

the updated code doesn't appear to allow you to list multiple colon seperated hosts

Didn't even know you where allowed to do that!

Is there documentation somewhere on how to create a export string? Neither exports(5), exportfs(8), rpc.mountd(8) nor nfs(5) explains how this is setup.

It (exports(5) DOES talk about colons, but only in relation to IPv6 hosts:

EXAMPLE
       /foo            2001:db8:9:e54::/64(rw) 192.0.2.0/24(rw)

Actually, this is on Linux. So this isn't a Linux option then…?

I'm not against ditching Solaris options support, I just feel that we should really, really try.. With this patch, I've at least tried to make it easier… ?=

behlendorf · 2014-10-24T16:42:32Z

The expected Solaris/Illumos syntax can be found in the share(1M) and share_nfs(1M) man pages. If you take a look at example 2 in share(1M) you'll see how ro, rw, and multiple hosts can be specified.

http://www.lehman.cuny.edu/cgi-bin/man-cgi?share+1
http://www.lehman.cuny.edu/cgi-bin/man-cgi?share_nfs+1

The Linux NFS syntax for this is very different. The code does a reasonable job today translating but this is one case it doesn't try to handle. The whole thing is further complicated by the fact that there are illumos nfs options which have no Linux equivalent and visa-versa.

It's very tempting to just leave it as is for now and make plans to just cut over at some point to Linux options. As I mentioned above, this appears to be what FreeBSD did.

so that it can be (re)used in other parts of libshare.

Example: Setting sharenfs to "rw=@192.168.69.8,no_subtree_check,no_root_squash,ro=@192.168.69.45,no_subtree_check,root_squash" will create the option string sec=sys,ro,no_subtree_check,no_root_squash,mountpoint,no_subtree_check,no_root_squash,no_subtree_check,root_squash which is then run on _each host_!. Part of this is "default" options. Instead, go through the option string, look for hosts and then make sure options for each host is kept apart by using a linked list (maintained by the ZFS list_* functions). Also, the default options should only be added to the list of options if setting sharenfs to "on" (and then to the '*' "host"). Closes: openzfs#2773

FransUrbo · 2015-10-19T12:36:44Z

@behlendorf Do you think you can spend an hour or two to look this over? It's now been running in the Debian GNU/Linux packages for almost a year and except for a minor problem in the beginning, I've heard nothing about this so I'm pretty sure it works just fine.

behlendorf

These changes need to be rebased on master so they apply cleanly. The should be easy since there's been very little churn in this file.

Since this change was originally proposed the ZFS Test Suite has been merged and gets run on every PR. In order to get test coverage on these modifications to the share support the zfs share/unshare tests need be enabled in the linux.run file and updated so most or all of them pass. If a few test cases are problematic we can leave them disabled for now. This would still be a huge step in the right direction. We can install whatever packages are needed in to the test VMs to support this.

Once we have automated test coverage and the tests are passing I'll be comfortable merging this change. It with also make it easier to improve this code in the future.

behlendorf · 2016-09-16T23:47:56Z

lib/libshare/nfs.c

 #include <unistd.h>
 #include <libzfs.h>
 #include <libshare.h>
 #include "libshare_impl.h"

+#if !defined(offsetof)
+#define	offsetof(s, m)  ((size_t)(&(((s *)0)->m)))
+#endif


Why was this needed, offsetof is part of stddef.h
http://man7.org/linux/man-pages/man3/offsetof.3.html

behlendorf · 2016-09-16T23:47:56Z

lib/libshare/nfs.c

+/* NOTE: share path is stored elsewhere */
+typedef struct nfs_share_list_s {
+	char	host[255];
+	char	opts[255];


Let's add #define's for these buffer sizes. It may make sense to move those defines and this structure to lib/libshare/nfs.h which would be analogous to lib/libshare/smb.h.

This is a NFS limitation, so I don't see the point in having this as a define..

https://linux.die.net/man/5/nfs

namlen=n The maximum length of a pathname component on this mount. If this option is not specified, the maximum length is negotiated with the server. In most cases, this maximum length is 255 characters.

behlendorf · 2016-09-16T23:47:56Z

lib/libshare/nfs.c

 		*plinux_hostspec = strdup(solaris_hostspec);
-	}


[cstyle] The { } are expected for the else block when need by the if portion.

behlendorf · 2016-09-16T23:47:56Z

lib/libshare/nfs.c


 #ifdef DEBUG
-	fprintf(stderr, "sharing %s with opts %s\n", hostpath, opts);
+	fprintf(stderr, "sharing %s with opts %s\n",
+		hostpath, (opts ? opts : "NULL"));


[cstyle] 4 space indent to continue a line.

behlendorf · 2016-09-16T23:47:56Z

lib/libshare/nfs.c

+	for (i = 0; i < 5; i++)
+		fprintf(stderr, "%s ", argv[i]);
+	fprintf(stderr, "\n");
+#endif


Do we still need these DEBUG blocks. If we really need to preserve this debugging I suggest updating the code to use dprintf(). Then this debugging can be enabled at run time rather than build time like this, ZFS_DEBUG="on" zfs share ....

behlendorf · 2016-09-16T23:47:56Z

lib/libshare/nfs.c

 	if (shareopts == NULL)
 		return (SA_OK);

-	rc = get_linux_shareopts(shareopts, &linux_opts);
+	linux_opts = calloc(sizeof (nfs_share_list_t), 1);


This needs to be checked for a NULL return.

behlendorf · 2016-09-16T23:47:56Z

lib/libshare/nfs.c

+	for (i = 0; i < 3; i++)
+		fprintf(stderr, "%s ", argv[i]);
+	fprintf(stderr, "\n");
+#endif


Drop or convert to dprintf()

behlendorf · 2016-09-16T23:47:56Z

lib/libshare/nfs.c

+
+#ifdef DEBUG
+	fprintf(stderr, "nfs_disable_share: %s\n", impl_share->sharepath);
+#endif


Drop or convert to dprintf()

behlendorf · 2016-09-16T23:47:56Z

lib/libshare/nfs.c

+	if (shareopts == NULL)
+		return (SA_OK);
+
+	linux_opts = calloc(sizeof (nfs_share_list_t), 1);


This needs to be checked for a NULL return.

behlendorf · 2016-09-16T23:47:56Z

lib/libshare/nfs.c

@@ -440,6 +522,8 @@ nfs_validate_shareopts(const char *shareopts)
 	char *linux_opts;
 	int rc;

+	linux_opts = calloc(sizeof (nfs_share_list_t), 1);


This needs to be checked for a NULL return.

behlendorf · 2016-10-01T00:22:03Z

Closing for now to reduce the number of open active PRs. We can absolutely consider merging this functionality once the patch is refreshed against master and we have some share test cases to validate this works.

dipack95 · 2019-07-16T15:38:34Z

@behlendorf @FransUrbo Issue #2773 still plagues us, and I noticed this patch attempts to fix that issue. Is there an ETA on this being merged in the project? I can help if required.

FransUrbo force-pushed the sharenfs_rewrite branch 6 times, most recently from 276b38f to 79dd502 Oct 11, 2014

behlendorf mentioned this pull request Oct 13, 2014

Cannot specify different NFS share options for multiple hosts #2773

Closed

FransUrbo force-pushed the sharenfs_rewrite branch 2 times, most recently from 8af02fe to ce5a839 Oct 26, 2014

behlendorf added the Component: Share label Oct 29, 2014

behlendorf added this to the 0.6.5 milestone Feb 6, 2015

FransUrbo closed this Feb 16, 2015

FransUrbo reopened this Mar 20, 2015

FransUrbo force-pushed the sharenfs_rewrite branch from ce5a839 to 91e9080 Mar 30, 2015

FransUrbo force-pushed the sharenfs_rewrite branch from 91e9080 to cdd67a1 Apr 11, 2015

FransUrbo mentioned this pull request Apr 19, 2015

security issue: sharenfs always gives read access for world #3319

Closed

FransUrbo force-pushed the sharenfs_rewrite branch from cdd67a1 to 0062e39 Apr 20, 2015

behlendorf removed this from the 0.6.5 milestone Jul 16, 2015

Move nfs.c:foreach_nfs_shareopt() to libshare.c:foreach_shareopt()

bcdd954

so that it can be (re)used in other parts of libshare.

FransUrbo force-pushed the sharenfs_rewrite branch from 0062e39 to a9337a1 Sep 8, 2015

FransUrbo mentioned this pull request Sep 8, 2015

Can't set Kerberos options with sharenfs #3738

Closed

FransUrbo force-pushed the sharenfs_rewrite branch 5 times, most recently from f230adb to 08f8958 Sep 8, 2015

FransUrbo force-pushed the sharenfs_rewrite branch from 08f8958 to 7d08880 Sep 11, 2015

FransUrbo mentioned this pull request Oct 5, 2015

sharenfs options not documented properly #3860

Open

behlendorf requested changes Sep 16, 2016

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behlendorf closed this Oct 1, 2016

openzfs / zfs Public

Rewrite of nfs.c to keep options per host separated. #2790

Rewrite of nfs.c to keep options per host separated. #2790

FransUrbo commented Oct 11, 2014

behlendorf commented Oct 23, 2014

FransUrbo commented Oct 24, 2014

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dipack95 commented Jul 16, 2019

openzfs / zfs Public

Rewrite of nfs.c to keep options per host separated. #2790

Rewrite of nfs.c to keep options per host separated. #2790

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