#!/usr/bin/perl

use strict;
use Test;

my $g_rootMount   = "/tmp/";

if(@ARGV != 2)
{
  print STDERR "Usage: mount_limit PVFS_CLUSTER NUM_MOUNTS\n";
  print STDERR "\tPVFS_CLUSTER - The mount info. i.e. pvfs2_server:port/fs_name\n";
  print STDERR "\tNUM_MOUNTS   - Number of times to mount the cluster\n";
  exit(1);
}

my $g_pvfsCluster = $ARGV[0];
my $g_numMounts   = $ARGV[1];

&execute_mounts($g_rootMount, 
                $g_pvfsCluster, 
                $g_numMounts);

#-------------------------------------------------------------------------------
# Name           : execute_mounts
# Parameter List : $rootMount   - Prefix to use for all mounts    
#                  $pvfsCluster - PVFS cluster to mount
#                  $numMounts   - Number of mounts to perform
#                  
#                  
# Return Values  : 0 - Success
#                  1 - Failed
# Comment        :
#-------------------------------------------------------------------------------
sub execute_mounts
{
  my @args = @_;
  
  my $rootMount   = $args[0];
  my $pvfsCluster = $args[1];
  my $numMounts   = $args[2];

  my $numMounted = 0;  
  my $dirPrefix  = "mount_limit.".$$; # append the PID to the end for uniqueness
  
  # Loop through and perform the mount of PVFS $nunMounts times
  my $counter;
  my $retVal;
  my $validRet = undef;
  
  print STDERR "*****Starting PVFS Mounts*****\n";
  print STDERR "Parameter List:\n";
  print STDERR "\tRoot Mount Dir   = $rootMount\n";
  print STDERR "\tPVFS Cluster     = $pvfsCluster\n";
  print STDERR "\tDir prefix       = $dirPrefix\n";
  print STDERR "\tNumber of Mounts = $numMounts\n";
  
  # Loop through and mount all the directories
  for($counter=0;$counter<$numMounts;$counter++)
  {
    my $dir;

    # Build the directory
    $dir= $rootMount.$dirPrefix.$counter;
    
    if(&make_dir($dir)) # If we could NOT create the directory
    {
      print STDERR "Unable to perform mkdir on $dir\n";
      # Unmount and remove all mounts that executed previously
      &clean_up($counter, $rootMount, $dirPrefix);
      
      # QUIT
      exit(1);
    }  
    
    if(&mount_dir($dir, $pvfsCluster)) # If we could not mount the directory
    {
      print STDERR "Unable to perform mount #", $counter + 1, " of $pvfsCluster to $dir\n";
      # Unmount and remove all mounts that executed previously
      &clean_up($counter, $rootMount, $dirPrefix);
      
      # QUIT
      exit(1);
    }
    $numMounted++;
    
    if($numMounted % 100 == 0)
    {
      print STDERR "$numMounted mounts completed\n";
    }
  }

  # Loop through and perform an LS on the directories
  # This needs to be done after ALL mounts complete, so that the reference count
  # to the directories doesn't change with each mount. 
  print STDERR "*****Performing ls checks*****\n";
  my $counter_increment = 1;
  if($numMounts > 100)
  {
        $counter_increment = 100;
  }
  for($counter=0;$counter<$numMounts;$counter+=$counter_increment)
  {
    my $dir;
    
    # Build the directory
    $dir= $rootMount.$dirPrefix.$counter;

    # Perform an ls on the directory
    $retVal = `ls -laR $dir`;
    $retVal =~ s/$dir//g;
    
    if(!defined $validRet)
    {
      $validRet = $retVal;
    }
    
    # Check the ls against the first ls
    if($retVal ne $validRet)
    {
      print STDERR "Unable to verify the LS\n";
      print STDERR "Valid   LS = $validRet\n";
      print STDERR "Current LS = $retVal\n";
      
      # Unmount and remove all mounts that executed previously
      # Use numMounted - 1 because this is a true counter, not an index
      &clean_up($numMounted-1, $rootMount, $dirPrefix);
      
      # QUIT
      exit(1);
    }

    if( ($counter+1) % 100 == 0 )
    {
      my $numRemoved = $counter+1;
      print STDERR "$numRemoved ls checks completed\n";
    }
  }  
  
  print STDERR "*****Removing Mounts*****\n";
  # Loop through and remove all mounts and directories
  for($counter=0;$counter<$numMounts;$counter++)
  {
    my $dir;
    
    # Build the directory
    $dir= $rootMount.$dirPrefix.$counter;

    &unmount_dir($dir);
    &delete_dir($dir);

    if( ($counter+1) % 100 == 0 )
    {
      my $numRemoved = $counter+1;
      print STDERR "$numRemoved un-mounted\n";
    }
  }
  
  exit(0);
}

#-------------------------------------------------------------------------------
# Name           : make_dir
# Parameter List : $dir - Directory to create
# Return Values  : 0 - Success
#                  1 - Failed
# Comment        :
#-------------------------------------------------------------------------------
sub make_dir
{
  my @args = @_;
  
  my $dir = $args[0]; 
  
  # Test to see if the directory to use for the mount exists
  if(system("test -d $dir")) # If the directory doesn't exist
  {
    if(system("mkdir -p $dir")) # If the mkdir doesn't work
    {
      # Couldn't create directory, return failed
      return 1; 
    }
  }
  
  return 0;
}

#-------------------------------------------------------------------------------
# Name           : mount_dir
# Parameter List : $dir         - Directory to mount to
#                  $pvfsCluster - PVFS Cluster to mount
# Return Values  : 0 - Success
#                  1 - Failed
# Comment        :
#-------------------------------------------------------------------------------
sub mount_dir
{
  my @args = @_;
  
  my $dir         = $args[0]; 
  my $pvfsCluster = $args[1];
  
  # Test to see if the directory to use for the mount exists
  if(system("mount -t pvfs2 $pvfsCluster $dir")) # If the mount doesn't work
  {
    # Couldn't mount directory, return failed
    return 1; 
  }
  
  return 0;
}

#-------------------------------------------------------------------------------
# Name           : clean_up
# Parameter List : $numMounted - The number of pvfs mounts to clean up
#                  $rootMount  - The root directory for all mounts
#                  $dirPrefix  - The directory prefix for mounts
# Return Values  : 0 - Success
#                  1 - Failed
# Comment        :
#-------------------------------------------------------------------------------
sub clean_up
{
  my @args = @_;

  my $numMounted = $args[0];
  my $rootMount  = $args[1];
  my $dirPrefix  = $args[2];
  
  my $counter;

  # Loop through and unmount and remove the directories we have already done
  for($counter=0;$counter<=$numMounted;$counter++)
  {
    my $dir;
        
    # Build the directory
    $dir= $rootMount.$dirPrefix.$counter;
    
    &unmount_dir($dir);
    &delete_dir($dir);
  }
}

#-------------------------------------------------------------------------------
# Name           : unmount_dir
# Parameter List : $dir - Directory to unmount
# Return Values  : 0 - Success
#                  1 - Failed
# Comment        :
#-------------------------------------------------------------------------------
sub unmount_dir
{
  my @args = @_;
  
  my $dir         = $args[0]; 
  
  # Test to see if the directory to use for the mount exists
  if(system("umount $dir")) # If the mount doesn't work
  {
    # Couldn't mount directory, return failed
    return 1; 
  }
  
  return 0;
}

#-------------------------------------------------------------------------------
# Name           : delete_dir
# Parameter List : $dir - Directory to unmount
# Return Values  : 0 - Success
#                  1 - Failed
# Comment        :
#-------------------------------------------------------------------------------
sub delete_dir
{
  my @args = @_;
  
  my $dir = $args[0];

  # Test to see if the directory to use for the mount exists
  if(system("rmdir $dir")) # If the mount doesn't work
  {
   # Couldn't mount directory, return failed
    return 1; 
  }
  
  return 0;
}