Re: [Tracker] how to handle this case (nfs share home directory among two PC)

[Rick Ju <Rick Ju Sun COM>]

Hi, Jamie,

For checking remote mounted directory, I wrote a simple prototype 
function. It uses getmntent in mntent.h to parse /etc/mtab.

If it looks OK, I will wrap it up as patch to use the SkipMountPoint option.

The prototype could compile in ubuntu.


-rick






> 2. Don't index remote mounted directories by default. We could also add 
> an option for this.  User could choose whether to index remote file 
> systems by default.
>     
>   
> > >> we would need to detect these - any suggestions? parse fstab/msatb?
> > >> patches welcome





Rick Ju wrote:
> Hi, Jamie,
>
>  >> latest svn now has readonly mode so first run one gets read/write and
>  >> subsequent ones are readonly only
>
> But this still has some conflicts. For example Machine A runs tracker 
> first and gets write access and indexing e.g. /data_machinA and  /etc. 
> And sometime later Machine A shutdown and Machine B gets write access 
> and indexing /data_machineB and /etc.
>
> This means the DB would contains /data_machineA, /data_machineB and 
> /etc. What make it worse is that /etc contains total different data in A 
> and B. So indexing data from different machines would mess up DB.
>
>
> jamie :
>   
> > On Tue, 2007-11-06 at 09:59 +0800, Rick Ju wrote:
> >   
> >     
> > > Hi, Jamie,
> > >
> > > Jerry, Halton and I discussed this several times last weeks. Here are 
> > > some suggestions.
> > >
> > > 1. Shared NFS home directory issue. In this case, 2+ machines runs 
> > > tracker with same DB and conflicts. A resolve is tracker use separate  
> > > preference/DB directory.
> > >
> > >  Such as:     ~/.tracker/machine-uuid-34738-34873/trackerDB
> > >     
> > >       
> > latest svn now has readonly mode so first run one gets read/write and
> > subsequent ones are readonly only
> >
> >   
> >     
> >
> >   
> >     
> > > This could not resolve all of course but it could work around many 
> > > conflict and performance issues.
> > >
> > > -rick
> > >
> > >
> > >
> > > jamie wrote:
> > >     
> > >       
> > > > > On Fri, 2007-10-12 at 21:28 +0800, Jerry Tan wrote:
> > > > >   
> > > > >     
> > > > >         
> > > > >           
> > > > > > I have two PC, both have its own OS,
> > > > > > but one account share the same home directory by nfs share.
> > > > > >
> > > > > > I can run trackerd on one PC,
> > > > > >
> > > > > > but can not start trackerd on another PC, because there is a lock.
> > > > > >
> > > > > >
> > > > > > How can I use tracker  on this PC?
> > > > > >
> > > > > >
> > > > > >     
> > > > > >       
> > > > > >           
> > > > > >             
> > > > > you risk corruption if NFS file locking is broken which is why we
> > > > > disabled it
> > > > >
> > > > > we had an option to move lock file to /tmp rather than $Home to allow
> > > > > multiple sessions from a central NFS home dir to be run - I will
> > > > > reenable it I suppose shortly
> > > > >
> > > > >
> > > > > _______________________________________________
> > > > > tracker-list mailing list
> > > > > tracker-list gnome org
> > > > > http://mail.gnome.org/mailman/listinfo/tracker-list
> > > > >   
> > > > >     
> > > > >         
> > > > >           
> > > > How about this?
> > > >
> > > > when the first trackerd runs from one PC, it own the lock.
> > > >
> > > > if one guy wants to start trackerd from another PC, tracker found the 
> > > > lock is there,
> > > > then it will start with noindex option,    it can still handle user request,
> > > > then tracker-search-tool can work on it also.
> > > > _______________________________________________
> > > > tracker-list mailing list
> > > > tracker-list gnome org
> > > > http://mail.gnome.org/mailman/listinfo/tracker-list
> > > >   
> > > >       
> > > >         
> > >     
> > >       
> > _______________________________________________
> > tracker-list mailing list
> > tracker-list gnome org
> > http://mail.gnome.org/mailman/listinfo/tracker-list
> >   
> >     
>
> _______________________________________________
> tracker-list mailing list
> tracker-list gnome org
> http://mail.gnome.org/mailman/listinfo/tracker-list
>   

#include <stdio.h>
#include <mntent.h>
#include <string.h>

// XXX always little capital ?
// XXX Any other remote fs type ?
const char * g_remote_fs_type_list[] = {"nfs", "smbfs", NULL};
const char * g_mnt_tab = "/etc/mtab";
// const char * g_mnt_tab = "/etc/mnttab"

bool is_remote_fs_type(const char *_fs_type)
{
  for (int i=0; g_remote_fs_type_list[i]; i++)
  {
     if (0 == strcmp(g_remote_fs_type_list[i], _fs_type))
       return true;
  }

  return false;
}

bool is_remote_directory(const char *_dir, const char *_mnt_tab)
{
  if (!_dir || !_mnt_tab)
    return false;

  FILE *file = setmntent(_mnt_tab, "r");
  if (!file)
    return false;

  bool rtn = false;
  struct mntent * ent =  getmntent(file);
  while(ent)
  {
    if (0 == strcmp(_dir, ent->mnt_dir) && is_remote_fs_type(ent->mnt_type))
    {
      rtn = true;
      break;
    }

    ent = getmntent(file);
  }

  endmntent(file);
  return rtn;
}

int main(void)
{
  bool rtn = false;
  FILE *file = setmntent(g_mnt_tab, "r");
  if (!file)
    return false;

  char tmp[256][2048];
  memset(tmp, 2048*256, 0);

  int i = 0;
  struct mntent * ent = getmntent(file);
  while(ent)
  {
    strcpy(tmp[i], ent->mnt_dir);
    i++;
    ent = getmntent(file);
  }
  endmntent(file);

  i = 0;
  while(tmp[i][0])
  {
    bool is_remote = is_remote_directory(tmp[i], g_mnt_tab);
    printf("Checking %s: ......  %s\n", tmp[i], is_remote?"Remote mounted":"Local mounted");
    i++;
  }
  return rtn;
}