From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:37782 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727404AbeJTWqa (ORCPT ); Sat, 20 Oct 2018 18:46:30 -0400 Subject: Re: [PATCH] [nfs-utils] fix issue: mount -osharecache failure but return 'true' To: =?UTF-8?B?5bC55YmR6Jm5?= Cc: "jiyin@redhat.com" , "linux-nfs@vger.kernel.org" References: <20181019080354.26141-1-jiyin@redhat.com> <907dd179-13d7-071e-8c60-eb9915762299@RedHat.com> <17c11e3b.5987.1668f873fb0.Coremail.yin-jianhong@163.com> From: Steve Dickson Message-ID: Date: Sat, 20 Oct 2018 10:35:48 -0400 MIME-Version: 1.0 In-Reply-To: <17c11e3b.5987.1668f873fb0.Coremail.yin-jianhong@163.com> Content-Type: text/plain; charset=utf-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: Hello, On 10/19/18 11:31 PM, 尹剑虹 wrote: > > Hi Steved > > The scenario is: these two mountings use different "context=" and sharecache option, in this case mount(2) return fail with EBUSY. Fair enough.... I did miss the different contexts... But we already have a routine that check mount points is_mountpoint() used my mountd. I would rather use that. I'll resend the patch... Thanks!! steved. > > Jianhong > > > > 尹剑虹 > 邮箱：yin-jianhong@163.com > > > > 签名由 网易邮箱大师 定制 > > On 10/20/2018 01:36, Steve Dickson wrote: > > > On 10/19/18 4:03 AM, jiyin@redhat.com wrote: > > From: "Jianhong.Yin" > > > > see: https://bugzilla.redhat.com/show_bug.cgi?id=1629705 > > mount.nfs4 -o context=system_u:object_r:user_home_dir_t:s0,sharecache $serv:$expdir $nfsmp > > mount.nfs4 -o context=system_u:object_r:xferlog_t:s0,sharecache $serv:$expdir $nfsmp2 > > ^^^ here mount fail, but return true. it confuse user! > Why should it fail? Two different mounts are being used and using -o sharecache > which is the default the way... > > steved. > > > > according: https://patchwork.kernel.org/patch/10602607/#22234047 > > add function is_mounted_already() > > -          if (errno == EBUSY) > > +          if (errno == EBUSY && is_mounted_already(mi->spec, mi->node)) > >                return EX_SUCCESS; > > > > Signed-off-by: Jianhong Yin > > --- > >  utils/mount/stropts.c | 31 ++++++++++++++++++++++++------- > >  1 file changed, 24 insertions(+), 7 deletions(-) > > > > diff --git a/utils/mount/stropts.c b/utils/mount/stropts.c > > index 4d2e37e..4be7e61 100644 > > --- a/utils/mount/stropts.c > > +++ b/utils/mount/stropts.c > > @@ -48,6 +48,7 @@ > >  #include "version.h" > >  #include "parse_dev.h" > >  #include "conffile.h" > > +#include > >   > >  #ifndef NFS_PROGRAM > >  #define NFS_PROGRAM     (100003) > > @@ -1056,6 +1057,27 @@ static int nfs_is_permanent_error(int error) > >       } > >  } > >   > > +static int is_mounted_already(const char *fsname, const char *dir) > > +{ > > +     struct mntent *ent; > > +     FILE *fp; > > +     int ret = 0; > > + > > +     fp = setmntent("/proc/mounts", "r"); > > +     if (fp == NULL) { > > +          perror("[unlikely] setmntent(3) fail"); > > +          exit(1); > > +     } > > +     while (NULL != (ent = getmntent(fp))) { > > +          if (!strcmp(ent->mnt_fsname, fsname) && !strcmp(ent->mnt_dir, dir)) { > > +               ret = 1; > > +               break; > > +          } > > +     } > > +     endmntent(fp); > > +     return ret; > > +} > > + > >  /* > >   * Handle "foreground" NFS mounts. > >   * > > @@ -1078,13 +1100,8 @@ static int nfsmount_fg(struct nfsmount_info *mi) > >            if (nfs_try_mount(mi)) > >                 return EX_SUCCESS; > >   > > -          if (errno == EBUSY) > > -               /* The only cause of EBUSY is if exactly the desired > > -                * filesystem is already mounted.  That can arguably > > -                * be seen as success.  "mount -a" tries to optimise > > -                * out this case but sometimes fails.  Help it out > > -                * by pretending everything is rosy > > -                */ > > +          /* if EBUSY is caused by re-mount, ignore the error */ > > +          if (errno == EBUSY && is_mounted_already(mi->spec, mi->node)) > >                 return EX_SUCCESS; > >   > >            if (nfs_is_permanent_error(errno)) > > >