Return-Path: linux-nfs-owner@vger.kernel.org Received: from mx1.redhat.com ([209.132.183.28]:28235 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757929Ab3EGQBk (ORCPT ); Tue, 7 May 2013 12:01:40 -0400 Message-ID: <51892562.1050903@RedHat.com> Date: Tue, 07 May 2013 12:01:38 -0400 From: Steve Dickson MIME-Version: 1.0 To: NeilBrown CC: NFS Subject: Re: [PATCH] mountd: Fix is_subdirectory again. References: <20130502170511.646e2717@notabene.brown> In-Reply-To: <20130502170511.646e2717@notabene.brown> Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-nfs-owner@vger.kernel.org List-ID: On 02/05/13 03:05, NeilBrown wrote: > > > Hi Steve, > I just noticed > > commit ebe2826ca571a3959c3b5c8e29686c621f2775cf > Author: Steve Dickson > Date: Sat Mar 23 10:30:17 2013 -0400 > > mountd: regression in crossmounts > > Sorry I missed the email you presumably sent me to let me know > that I had caused a regression. Yes I should have... That was my bad... > > Here is the proper fix. Yes it does work.. thanks! The new is committed! steved. > > Thanks, > NeilBrown > > > Subject: [PATCH] mountd: Fix is_subdirectory again. > > commit ebe2826ca571a (mountd: regression in crossmounts) > said it was: > Reverting the logic of commit 8e2fb3fc until > a better solution can be found for the original > problem. > > here is the "something better". > > The problem was that is_subdirectory() would also succeed if the two > directories were the same. This is needed for path_matches() which > needs to see if the child is same-or-descendant. > > So this patch rearranges path_matches() to do the "are they the same" > test itself and only bother with is_subdirectory() if it they are not > the same. > > So now is_subdirectory() can be strict, and so can be usable for > subexport(), which needs a strong 'in subdirectory - not the same' test. > > Signed-off-by: NeilBrown > > diff --git a/utils/mountd/cache.c b/utils/mountd/cache.c > index 737927c..517aa62 100644 > --- a/utils/mountd/cache.c > +++ b/utils/mountd/cache.c > @@ -347,20 +347,26 @@ static char *next_mnt(void **v, char *p) > > static int is_subdirectory(char *child, char *parent) > { > + /* Check is child is strictly a subdirectory of > + * parent or a more distant descendant. > + */ > size_t l = strlen(parent); > > - if (strcmp(parent, "/") == 0) > + if (strcmp(parent, "/") == 0 && child[1] != 0) > return 1; > > - return strcmp(child, parent) == 0 > - || (strncmp(child, parent, l) == 0 && child[l] == '/'); > + return (strncmp(child, parent, l) == 0 && child[l] == '/'); > } > > static int path_matches(nfs_export *exp, char *path) > { > - if (exp->m_export.e_flags & NFSEXP_CROSSMOUNT) > - return is_subdirectory(path, exp->m_export.e_path); > - return strcmp(path, exp->m_export.e_path) == 0; > + /* Does the path match the export? I.e. is it an > + * exact match, or does the export have CROSSMOUNT, and path > + * is a descendant? > + */ > + return strcmp(path, exp->m_export.e_path) == 0 > + || ((exp->m_export.e_flags & NFSEXP_CROSSMOUNT) > + && is_subdirectory(path, exp->m_export.e_path)); > } > > static int > @@ -369,15 +375,13 @@ export_matches(nfs_export *exp, char *dom, char *path, struct addrinfo *ai) > return path_matches(exp, path) && client_matches(exp, dom, ai); > } > > -/* True iff e1 is a child of e2 and e2 has crossmnt set: */ > +/* True iff e1 is a child of e2 (or descendant) and e2 has crossmnt set: */ > static bool subexport(struct exportent *e1, struct exportent *e2) > { > char *p1 = e1->e_path, *p2 = e2->e_path; > - size_t l2 = strlen(p2); > > return e2->e_flags & NFSEXP_CROSSMOUNT > - && strncmp(p1, p2, l2) == 0 > - && p1[l2] == '/'; > + && is_subdirectory(p1, p2); > } > > struct parsed_fsid { >