Oops, I did my usual and forgot to attach the patch.
Here it is, rick
----- Original Message -----
> Doug Rabson wrote:
> > You could add a single integer-valued vfsopt which holds the
> > high-order
> > bits of f_flags?
> >
> I have created a patch that does this. It is on
> https://reviews.freebsd.org/D2506
> (I have also attached it here, for those who don't use Phabricator.)
>
> Please review/comment on this. (Feel free to add yourself as a
> reviewer, etc.)
>
> Also, David, if you can test this patch, it would be appreciated.
>
> Thanks for the suggestion Doug, rick
>
> > On 7 May 2015 at 02:10, Rick Macklem <[email protected]> wrote:
> >
> > > David Boyd reported a problem to freebsd-current@ w.r.t. the
> > > MNT_AUTOMOUNTED
> > > flag getting cleared by mountd.
> > > http://docs.FreeBSD.org/cgi/mid.cgi?1429477202.29812.38.camel
> > > I just took a look at this and it's kinda ugly...
> > >
> > > mountd acquires a list of mounts via getmntinfo() and then does
> > > an
> > > nmount() for each of them to get rid of any exports. It uses
> > > f_flags from the statfs returned by getmntinfo() as the 3rd
> > > argument to nmount().
> > > --> Since nmount()s 3rd argument is a "int", it silently drops
> > > any
> > > MNT_xx flag in the high order 32bits of f_flags. At this
> > > time,
> > > it happens that MNT_AUTOMOUNTED is the only one, but...
> > >
> > > I can think of a couple of ways to fix this, but I don't like any
> > > of
> > > them;-)
> > >
> > > 1) I suppose mountd could check for each flag set in f_flags and
> > > generate
> > > a vfsopts string for it, but that means that every time a new
> > > flag
> > > that
> > > can be updated is added to MNT_xx, this mountd.c code would have
> > > to
> > > updated.
> > > --> Ugly!!
> > >
> > > 2) Require that all flags in MNT_UPDATEMASK be in the low order
> > > 32bits.
> > > I wouldn`t mind this except in means that the MNT_xx flags
> > > must
> > > be
> > > redefined
> > > and I don`t think that could get MFC`d.
> > >
> > > 3) Add a new newernmount(2) which has a 64bit flags argument
> > > instead of
> > > int.
> > >
> > > Hopefully someone can think of a nice way to fix this, rick
> > > _______________________________________________
> > > [email protected] mailing list
> > > http://lists.freebsd.org/mailman/listinfo/freebsd-current
> > > To unsubscribe, send any mail to
> > > "[email protected]"
> > >
> > _______________________________________________
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> >
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>
--- kern/vfs_mount.c.savmnt 2015-05-09 19:30:14.000000000 -0400
+++ kern/vfs_mount.c 2015-05-10 08:34:45.000000000 -0400
@@ -537,6 +537,7 @@ vfs_donmount(struct thread *td, uint64_t
struct vfsopt *opt, *tmp_opt;
char *fstype, *fspath, *errmsg;
int error, fstypelen, fspathlen, errmsg_len, errmsg_pos;
+ uint64_t fsflag_high;
errmsg = fspath = NULL;
errmsg_len = fspathlen = 0;
@@ -653,6 +654,20 @@ vfs_donmount(struct thread *td, uint64_t
fsflags |= MNT_AUTOMOUNTED;
vfs_freeopt(optlist, opt);
}
+ else if (strcmp(opt->name, "fsflaghigh") == 0) {
+ /*
+ * This option allows a process doing a mount update
+ * to set all the high order 32bits of mnt_flag with
+ * one option. This is needed, since nmount(2)
+ * accepts an "int" option and, therefore, only takes
+ * the low order 32bits.
+ */
+ if (vfs_copyopt(optlist, "fsflaghigh",
+ &fsflag_high, sizeof(fsflag_high)) == 0 &&
+ (fsflag_high & 0xffffffffULL) == 0)
+ fsflags |= fsflag_high;
+ vfs_freeopt(optlist, opt);
+ }
}
/*
--- usr.sbin/mountd/mountd.c.orig 2015-05-09 22:04:15.000000000 -0400
+++ usr.sbin/mountd/mountd.c 2015-05-09 22:27:06.000000000 -0400
@@ -1649,6 +1649,7 @@ get_exportlist(void)
int iovlen;
int done;
struct nfsex_args eargs;
+ uint64_t fsflag_high;
if (suspend_nfsd != 0)
(void)nfssvc(NFSSVC_SUSPENDNFSD, NULL);
@@ -1706,6 +1707,8 @@ get_exportlist(void)
build_iovec(&iov, &iovlen, "update", NULL, 0);
build_iovec(&iov, &iovlen, "export", &export, sizeof(export));
build_iovec(&iov, &iovlen, "errmsg", errmsg, sizeof(errmsg));
+ build_iovec(&iov, &iovlen, "fsflaghigh", &fsflag_high,
+ sizeof(fsflag_high));
}
for (i = 0; i < num; i++) {
@@ -1736,6 +1739,9 @@ get_exportlist(void)
iov[3].iov_len = strlen(fsp->f_mntonname) + 1;
iov[5].iov_base = fsp->f_mntfromname;
iov[5].iov_len = strlen(fsp->f_mntfromname) + 1;
+ /* Use "fsflaghigh" to set the high order bits of f_flags. */
+ fsflag_high = (fsp->f_flags & 0xffffffff00000000ULL);
+
errmsg[0] = '\0';
/*
@@ -2394,6 +2400,7 @@ do_mount(struct exportlist *ep, struct g
int i, iovlen;
int ret;
struct nfsex_args nfsea;
+ uint64_t fsflag_high;
eap = &nfsea.export;
@@ -2429,6 +2436,12 @@ do_mount(struct exportlist *ep, struct g
build_iovec(&iov, &iovlen, "export", eap,
sizeof (struct export_args));
build_iovec(&iov, &iovlen, "errmsg", errmsg, sizeof(errmsg));
+
+ /* Use "fsflaghigh" to set the high order bits of f_flags. */
+ fsflag_high = (fsb->f_flags & 0xffffffff00000000ULL);
+ if (fsflag_high != 0)
+ build_iovec(&iov, &iovlen, "fsflaghigh", &fsflag_high,
+ sizeof(fsflag_high));
}
while (!done) {
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